| /* |
| * linux/kernel/printk.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * Modified to make sys_syslog() more flexible: added commands to |
| * return the last 4k of kernel messages, regardless of whether |
| * they've been read or not. Added option to suppress kernel printk's |
| * to the console. Added hook for sending the console messages |
| * elsewhere, in preparation for a serial line console (someday). |
| * Ted Ts'o, 2/11/93. |
| * Modified for sysctl support, 1/8/97, Chris Horn. |
| * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
| * manfred@colorfullife.com |
| * Rewrote bits to get rid of console_lock |
| * 01Mar01 Andrew Morton |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/tty.h> |
| #include <linux/tty_driver.h> |
| #include <linux/console.h> |
| #include <linux/init.h> |
| #include <linux/jiffies.h> |
| #include <linux/nmi.h> |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/interrupt.h> /* For in_interrupt() */ |
| #include <linux/delay.h> |
| #include <linux/smp.h> |
| #include <linux/security.h> |
| #include <linux/bootmem.h> |
| #include <linux/memblock.h> |
| #include <linux/aio.h> |
| #include <linux/syscalls.h> |
| #include <linux/kexec.h> |
| #include <linux/kdb.h> |
| #include <linux/ratelimit.h> |
| #include <linux/kmsg_dump.h> |
| #include <linux/syslog.h> |
| #include <linux/cpu.h> |
| #include <linux/notifier.h> |
| #include <linux/rculist.h> |
| #include <linux/poll.h> |
| #include <linux/irq_work.h> |
| #include <linux/utsname.h> |
| |
| #include <asm/uaccess.h> |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/printk.h> |
| |
| /* printk's without a loglevel use this.. */ |
| #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL |
| |
| /* We show everything that is MORE important than this.. */ |
| #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ |
| #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ |
| |
| int console_printk[4] = { |
| DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ |
| DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ |
| MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ |
| DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ |
| }; |
| |
| /* |
| * Low level drivers may need that to know if they can schedule in |
| * their unblank() callback or not. So let's export it. |
| */ |
| int oops_in_progress; |
| EXPORT_SYMBOL(oops_in_progress); |
| |
| /* |
| * console_sem protects the console_drivers list, and also |
| * provides serialisation for access to the entire console |
| * driver system. |
| */ |
| static DEFINE_SEMAPHORE(console_sem); |
| struct console *console_drivers; |
| EXPORT_SYMBOL_GPL(console_drivers); |
| |
| #ifdef CONFIG_LOCKDEP |
| static struct lockdep_map console_lock_dep_map = { |
| .name = "console_lock" |
| }; |
| #endif |
| |
| /* |
| * This is used for debugging the mess that is the VT code by |
| * keeping track if we have the console semaphore held. It's |
| * definitely not the perfect debug tool (we don't know if _WE_ |
| * hold it are racing, but it helps tracking those weird code |
| * path in the console code where we end up in places I want |
| * locked without the console sempahore held |
| */ |
| static int console_locked, console_suspended; |
| |
| /* |
| * If exclusive_console is non-NULL then only this console is to be printed to. |
| */ |
| static struct console *exclusive_console; |
| |
| /* |
| * Array of consoles built from command line options (console=) |
| */ |
| struct console_cmdline |
| { |
| char name[8]; /* Name of the driver */ |
| int index; /* Minor dev. to use */ |
| char *options; /* Options for the driver */ |
| #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| char *brl_options; /* Options for braille driver */ |
| #endif |
| }; |
| |
| #define MAX_CMDLINECONSOLES 8 |
| |
| static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; |
| static int selected_console = -1; |
| static int preferred_console = -1; |
| int console_set_on_cmdline; |
| EXPORT_SYMBOL(console_set_on_cmdline); |
| |
| /* Flag: console code may call schedule() */ |
| static int console_may_schedule; |
| |
| /* |
| * The printk log buffer consists of a chain of concatenated variable |
| * length records. Every record starts with a record header, containing |
| * the overall length of the record. |
| * |
| * The heads to the first and last entry in the buffer, as well as the |
| * sequence numbers of these both entries are maintained when messages |
| * are stored.. |
| * |
| * If the heads indicate available messages, the length in the header |
| * tells the start next message. A length == 0 for the next message |
| * indicates a wrap-around to the beginning of the buffer. |
| * |
| * Every record carries the monotonic timestamp in microseconds, as well as |
| * the standard userspace syslog level and syslog facility. The usual |
| * kernel messages use LOG_KERN; userspace-injected messages always carry |
| * a matching syslog facility, by default LOG_USER. The origin of every |
| * message can be reliably determined that way. |
| * |
| * The human readable log message directly follows the message header. The |
| * length of the message text is stored in the header, the stored message |
| * is not terminated. |
| * |
| * Optionally, a message can carry a dictionary of properties (key/value pairs), |
| * to provide userspace with a machine-readable message context. |
| * |
| * Examples for well-defined, commonly used property names are: |
| * DEVICE=b12:8 device identifier |
| * b12:8 block dev_t |
| * c127:3 char dev_t |
| * n8 netdev ifindex |
| * +sound:card0 subsystem:devname |
| * SUBSYSTEM=pci driver-core subsystem name |
| * |
| * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value |
| * follows directly after a '=' character. Every property is terminated by |
| * a '\0' character. The last property is not terminated. |
| * |
| * Example of a message structure: |
| * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec |
| * 0008 34 00 record is 52 bytes long |
| * 000a 0b 00 text is 11 bytes long |
| * 000c 1f 00 dictionary is 23 bytes long |
| * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) |
| * 0010 69 74 27 73 20 61 20 6c "it's a l" |
| * 69 6e 65 "ine" |
| * 001b 44 45 56 49 43 "DEVIC" |
| * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" |
| * 52 49 56 45 52 3d 62 75 "RIVER=bu" |
| * 67 "g" |
| * 0032 00 00 00 padding to next message header |
| * |
| * The 'struct log' buffer header must never be directly exported to |
| * userspace, it is a kernel-private implementation detail that might |
| * need to be changed in the future, when the requirements change. |
| * |
| * /dev/kmsg exports the structured data in the following line format: |
| * "level,sequnum,timestamp;<message text>\n" |
| * |
| * The optional key/value pairs are attached as continuation lines starting |
| * with a space character and terminated by a newline. All possible |
| * non-prinatable characters are escaped in the "\xff" notation. |
| * |
| * Users of the export format should ignore possible additional values |
| * separated by ',', and find the message after the ';' character. |
| */ |
| |
| enum log_flags { |
| LOG_NOCONS = 1, /* already flushed, do not print to console */ |
| LOG_NEWLINE = 2, /* text ended with a newline */ |
| LOG_PREFIX = 4, /* text started with a prefix */ |
| LOG_CONT = 8, /* text is a fragment of a continuation line */ |
| }; |
| |
| struct log { |
| u64 ts_nsec; /* timestamp in nanoseconds */ |
| u16 len; /* length of entire record */ |
| u16 text_len; /* length of text buffer */ |
| u16 dict_len; /* length of dictionary buffer */ |
| u8 facility; /* syslog facility */ |
| u8 flags:5; /* internal record flags */ |
| u8 level:3; /* syslog level */ |
| }; |
| |
| /* |
| * The logbuf_lock protects kmsg buffer, indices, counters. It is also |
| * used in interesting ways to provide interlocking in console_unlock(); |
| */ |
| static DEFINE_RAW_SPINLOCK(logbuf_lock); |
| |
| #ifdef CONFIG_PRINTK |
| DECLARE_WAIT_QUEUE_HEAD(log_wait); |
| /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
| static u64 syslog_seq; |
| static u32 syslog_idx; |
| static enum log_flags syslog_prev; |
| static size_t syslog_partial; |
| |
| /* index and sequence number of the first record stored in the buffer */ |
| static u64 log_first_seq; |
| static u32 log_first_idx; |
| |
| /* index and sequence number of the next record to store in the buffer */ |
| static u64 log_next_seq; |
| static u32 log_next_idx; |
| |
| /* the next printk record to write to the console */ |
| static u64 console_seq; |
| static u32 console_idx; |
| static enum log_flags console_prev; |
| |
| /* the next printk record to read after the last 'clear' command */ |
| static u64 clear_seq; |
| static u32 clear_idx; |
| |
| #define PREFIX_MAX 32 |
| #define LOG_LINE_MAX 1024 - PREFIX_MAX |
| |
| /* record buffer */ |
| #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) |
| #define LOG_ALIGN 4 |
| #else |
| #define LOG_ALIGN __alignof__(struct log) |
| #endif |
| #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
| static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
| static char *log_buf = __log_buf; |
| static u32 log_buf_len = __LOG_BUF_LEN; |
| |
| /* cpu currently holding logbuf_lock */ |
| static volatile unsigned int logbuf_cpu = UINT_MAX; |
| |
| /* human readable text of the record */ |
| static char *log_text(const struct log *msg) |
| { |
| return (char *)msg + sizeof(struct log); |
| } |
| |
| /* optional key/value pair dictionary attached to the record */ |
| static char *log_dict(const struct log *msg) |
| { |
| return (char *)msg + sizeof(struct log) + msg->text_len; |
| } |
| |
| /* get record by index; idx must point to valid msg */ |
| static struct log *log_from_idx(u32 idx) |
| { |
| struct log *msg = (struct log *)(log_buf + idx); |
| |
| /* |
| * A length == 0 record is the end of buffer marker. Wrap around and |
| * read the message at the start of the buffer. |
| */ |
| if (!msg->len) |
| return (struct log *)log_buf; |
| return msg; |
| } |
| |
| /* get next record; idx must point to valid msg */ |
| static u32 log_next(u32 idx) |
| { |
| struct log *msg = (struct log *)(log_buf + idx); |
| |
| /* length == 0 indicates the end of the buffer; wrap */ |
| /* |
| * A length == 0 record is the end of buffer marker. Wrap around and |
| * read the message at the start of the buffer as *this* one, and |
| * return the one after that. |
| */ |
| if (!msg->len) { |
| msg = (struct log *)log_buf; |
| return msg->len; |
| } |
| return idx + msg->len; |
| } |
| |
| /* insert record into the buffer, discard old ones, update heads */ |
| static void log_store(int facility, int level, |
| enum log_flags flags, u64 ts_nsec, |
| const char *dict, u16 dict_len, |
| const char *text, u16 text_len) |
| { |
| struct log *msg; |
| u32 size, pad_len; |
| |
| /* number of '\0' padding bytes to next message */ |
| size = sizeof(struct log) + text_len + dict_len; |
| pad_len = (-size) & (LOG_ALIGN - 1); |
| size += pad_len; |
| |
| while (log_first_seq < log_next_seq) { |
| u32 free; |
| |
| if (log_next_idx > log_first_idx) |
| free = max(log_buf_len - log_next_idx, log_first_idx); |
| else |
| free = log_first_idx - log_next_idx; |
| |
| if (free > size + sizeof(struct log)) |
| break; |
| |
| /* drop old messages until we have enough contiuous space */ |
| log_first_idx = log_next(log_first_idx); |
| log_first_seq++; |
| } |
| |
| if (log_next_idx + size + sizeof(struct log) >= log_buf_len) { |
| /* |
| * This message + an additional empty header does not fit |
| * at the end of the buffer. Add an empty header with len == 0 |
| * to signify a wrap around. |
| */ |
| memset(log_buf + log_next_idx, 0, sizeof(struct log)); |
| log_next_idx = 0; |
| } |
| |
| /* fill message */ |
| msg = (struct log *)(log_buf + log_next_idx); |
| memcpy(log_text(msg), text, text_len); |
| msg->text_len = text_len; |
| memcpy(log_dict(msg), dict, dict_len); |
| msg->dict_len = dict_len; |
| msg->facility = facility; |
| msg->level = level & 7; |
| msg->flags = flags & 0x1f; |
| if (ts_nsec > 0) |
| msg->ts_nsec = ts_nsec; |
| else |
| msg->ts_nsec = local_clock(); |
| memset(log_dict(msg) + dict_len, 0, pad_len); |
| msg->len = sizeof(struct log) + text_len + dict_len + pad_len; |
| |
| /* insert message */ |
| log_next_idx += msg->len; |
| log_next_seq++; |
| } |
| |
| #ifdef CONFIG_SECURITY_DMESG_RESTRICT |
| int dmesg_restrict = 1; |
| #else |
| int dmesg_restrict; |
| #endif |
| |
| static int syslog_action_restricted(int type) |
| { |
| if (dmesg_restrict) |
| return 1; |
| /* |
| * Unless restricted, we allow "read all" and "get buffer size" |
| * for everybody. |
| */ |
| return type != SYSLOG_ACTION_READ_ALL && |
| type != SYSLOG_ACTION_SIZE_BUFFER; |
| } |
| |
| static int check_syslog_permissions(int type, bool from_file) |
| { |
| /* |
| * If this is from /proc/kmsg and we've already opened it, then we've |
| * already done the capabilities checks at open time. |
| */ |
| if (from_file && type != SYSLOG_ACTION_OPEN) |
| return 0; |
| |
| if (syslog_action_restricted(type)) { |
| if (capable(CAP_SYSLOG)) |
| return 0; |
| /* |
| * For historical reasons, accept CAP_SYS_ADMIN too, with |
| * a warning. |
| */ |
| if (capable(CAP_SYS_ADMIN)) { |
| pr_warn_once("%s (%d): Attempt to access syslog with " |
| "CAP_SYS_ADMIN but no CAP_SYSLOG " |
| "(deprecated).\n", |
| current->comm, task_pid_nr(current)); |
| return 0; |
| } |
| return -EPERM; |
| } |
| return security_syslog(type); |
| } |
| |
| |
| /* /dev/kmsg - userspace message inject/listen interface */ |
| struct devkmsg_user { |
| u64 seq; |
| u32 idx; |
| enum log_flags prev; |
| struct mutex lock; |
| char buf[8192]; |
| }; |
| |
| static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, |
| unsigned long count, loff_t pos) |
| { |
| char *buf, *line; |
| int i; |
| int level = default_message_loglevel; |
| int facility = 1; /* LOG_USER */ |
| size_t len = iov_length(iv, count); |
| ssize_t ret = len; |
| |
| if (len > LOG_LINE_MAX) |
| return -EINVAL; |
| buf = kmalloc(len+1, GFP_KERNEL); |
| if (buf == NULL) |
| return -ENOMEM; |
| |
| line = buf; |
| for (i = 0; i < count; i++) { |
| if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) { |
| ret = -EFAULT; |
| goto out; |
| } |
| line += iv[i].iov_len; |
| } |
| |
| /* |
| * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace |
| * the decimal value represents 32bit, the lower 3 bit are the log |
| * level, the rest are the log facility. |
| * |
| * If no prefix or no userspace facility is specified, we |
| * enforce LOG_USER, to be able to reliably distinguish |
| * kernel-generated messages from userspace-injected ones. |
| */ |
| line = buf; |
| if (line[0] == '<') { |
| char *endp = NULL; |
| |
| i = simple_strtoul(line+1, &endp, 10); |
| if (endp && endp[0] == '>') { |
| level = i & 7; |
| if (i >> 3) |
| facility = i >> 3; |
| endp++; |
| len -= endp - line; |
| line = endp; |
| } |
| } |
| line[len] = '\0'; |
| |
| printk_emit(facility, level, NULL, 0, "%s", line); |
| out: |
| kfree(buf); |
| return ret; |
| } |
| |
| static ssize_t devkmsg_read(struct file *file, char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| struct devkmsg_user *user = file->private_data; |
| struct log *msg; |
| u64 ts_usec; |
| size_t i; |
| char cont = '-'; |
| size_t len; |
| ssize_t ret; |
| |
| if (!user) |
| return -EBADF; |
| |
| ret = mutex_lock_interruptible(&user->lock); |
| if (ret) |
| return ret; |
| raw_spin_lock_irq(&logbuf_lock); |
| while (user->seq == log_next_seq) { |
| if (file->f_flags & O_NONBLOCK) { |
| ret = -EAGAIN; |
| raw_spin_unlock_irq(&logbuf_lock); |
| goto out; |
| } |
| |
| raw_spin_unlock_irq(&logbuf_lock); |
| ret = wait_event_interruptible(log_wait, |
| user->seq != log_next_seq); |
| if (ret) |
| goto out; |
| raw_spin_lock_irq(&logbuf_lock); |
| } |
| |
| if (user->seq < log_first_seq) { |
| /* our last seen message is gone, return error and reset */ |
| user->idx = log_first_idx; |
| user->seq = log_first_seq; |
| ret = -EPIPE; |
| raw_spin_unlock_irq(&logbuf_lock); |
| goto out; |
| } |
| |
| msg = log_from_idx(user->idx); |
| ts_usec = msg->ts_nsec; |
| do_div(ts_usec, 1000); |
| |
| /* |
| * If we couldn't merge continuation line fragments during the print, |
| * export the stored flags to allow an optional external merge of the |
| * records. Merging the records isn't always neccessarily correct, like |
| * when we hit a race during printing. In most cases though, it produces |
| * better readable output. 'c' in the record flags mark the first |
| * fragment of a line, '+' the following. |
| */ |
| if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT)) |
| cont = 'c'; |
| else if ((msg->flags & LOG_CONT) || |
| ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))) |
| cont = '+'; |
| |
| len = sprintf(user->buf, "%u,%llu,%llu,%c;", |
| (msg->facility << 3) | msg->level, |
| user->seq, ts_usec, cont); |
| user->prev = msg->flags; |
| |
| /* escape non-printable characters */ |
| for (i = 0; i < msg->text_len; i++) { |
| unsigned char c = log_text(msg)[i]; |
| |
| if (c < ' ' || c >= 127 || c == '\\') |
| len += sprintf(user->buf + len, "\\x%02x", c); |
| else |
| user->buf[len++] = c; |
| } |
| user->buf[len++] = '\n'; |
| |
| if (msg->dict_len) { |
| bool line = true; |
| |
| for (i = 0; i < msg->dict_len; i++) { |
| unsigned char c = log_dict(msg)[i]; |
| |
| if (line) { |
| user->buf[len++] = ' '; |
| line = false; |
| } |
| |
| if (c == '\0') { |
| user->buf[len++] = '\n'; |
| line = true; |
| continue; |
| } |
| |
| if (c < ' ' || c >= 127 || c == '\\') { |
| len += sprintf(user->buf + len, "\\x%02x", c); |
| continue; |
| } |
| |
| user->buf[len++] = c; |
| } |
| user->buf[len++] = '\n'; |
| } |
| |
| user->idx = log_next(user->idx); |
| user->seq++; |
| raw_spin_unlock_irq(&logbuf_lock); |
| |
| if (len > count) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (copy_to_user(buf, user->buf, len)) { |
| ret = -EFAULT; |
| goto out; |
| } |
| ret = len; |
| out: |
| mutex_unlock(&user->lock); |
| return ret; |
| } |
| |
| static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) |
| { |
| struct devkmsg_user *user = file->private_data; |
| loff_t ret = 0; |
| |
| if (!user) |
| return -EBADF; |
| if (offset) |
| return -ESPIPE; |
| |
| raw_spin_lock_irq(&logbuf_lock); |
| switch (whence) { |
| case SEEK_SET: |
| /* the first record */ |
| user->idx = log_first_idx; |
| user->seq = log_first_seq; |
| break; |
| case SEEK_DATA: |
| /* |
| * The first record after the last SYSLOG_ACTION_CLEAR, |
| * like issued by 'dmesg -c'. Reading /dev/kmsg itself |
| * changes no global state, and does not clear anything. |
| */ |
| user->idx = clear_idx; |
| user->seq = clear_seq; |
| break; |
| case SEEK_END: |
| /* after the last record */ |
| user->idx = log_next_idx; |
| user->seq = log_next_seq; |
| break; |
| default: |
| ret = -EINVAL; |
| } |
| raw_spin_unlock_irq(&logbuf_lock); |
| return ret; |
| } |
| |
| static unsigned int devkmsg_poll(struct file *file, poll_table *wait) |
| { |
| struct devkmsg_user *user = file->private_data; |
| int ret = 0; |
| |
| if (!user) |
| return POLLERR|POLLNVAL; |
| |
| poll_wait(file, &log_wait, wait); |
| |
| raw_spin_lock_irq(&logbuf_lock); |
| if (user->seq < log_next_seq) { |
| /* return error when data has vanished underneath us */ |
| if (user->seq < log_first_seq) |
| ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; |
| else |
| ret = POLLIN|POLLRDNORM; |
| } |
| raw_spin_unlock_irq(&logbuf_lock); |
| |
| return ret; |
| } |
| |
| static int devkmsg_open(struct inode *inode, struct file *file) |
| { |
| struct devkmsg_user *user; |
| int err; |
| |
| /* write-only does not need any file context */ |
| if ((file->f_flags & O_ACCMODE) == O_WRONLY) |
| return 0; |
| |
| err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, |
| SYSLOG_FROM_READER); |
| if (err) |
| return err; |
| |
| user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); |
| if (!user) |
| return -ENOMEM; |
| |
| mutex_init(&user->lock); |
| |
| raw_spin_lock_irq(&logbuf_lock); |
| user->idx = log_first_idx; |
| user->seq = log_first_seq; |
| raw_spin_unlock_irq(&logbuf_lock); |
| |
| file->private_data = user; |
| return 0; |
| } |
| |
| static int devkmsg_release(struct inode *inode, struct file *file) |
| { |
| struct devkmsg_user *user = file->private_data; |
| |
| if (!user) |
| return 0; |
| |
| mutex_destroy(&user->lock); |
| kfree(user); |
| return 0; |
| } |
| |
| const struct file_operations kmsg_fops = { |
| .open = devkmsg_open, |
| .read = devkmsg_read, |
| .aio_write = devkmsg_writev, |
| .llseek = devkmsg_llseek, |
| .poll = devkmsg_poll, |
| .release = devkmsg_release, |
| }; |
| |
| #ifdef CONFIG_KEXEC |
| /* |
| * This appends the listed symbols to /proc/vmcoreinfo |
| * |
| * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to |
| * obtain access to symbols that are otherwise very difficult to locate. These |
| * symbols are specifically used so that utilities can access and extract the |
| * dmesg log from a vmcore file after a crash. |
| */ |
| void log_buf_kexec_setup(void) |
| { |
| VMCOREINFO_SYMBOL(log_buf); |
| VMCOREINFO_SYMBOL(log_buf_len); |
| VMCOREINFO_SYMBOL(log_first_idx); |
| VMCOREINFO_SYMBOL(log_next_idx); |
| /* |
| * Export struct log size and field offsets. User space tools can |
| * parse it and detect any changes to structure down the line. |
| */ |
| VMCOREINFO_STRUCT_SIZE(log); |
| VMCOREINFO_OFFSET(log, ts_nsec); |
| VMCOREINFO_OFFSET(log, len); |
| VMCOREINFO_OFFSET(log, text_len); |
| VMCOREINFO_OFFSET(log, dict_len); |
| } |
| #endif |
| |
| /* requested log_buf_len from kernel cmdline */ |
| static unsigned long __initdata new_log_buf_len; |
| |
| /* save requested log_buf_len since it's too early to process it */ |
| static int __init log_buf_len_setup(char *str) |
| { |
| unsigned size = memparse(str, &str); |
| |
| if (size) |
| size = roundup_pow_of_two(size); |
| if (size > log_buf_len) |
| new_log_buf_len = size; |
| |
| return 0; |
| } |
| early_param("log_buf_len", log_buf_len_setup); |
| |
| void __init setup_log_buf(int early) |
| { |
| unsigned long flags; |
| char *new_log_buf; |
| int free; |
| |
| if (!new_log_buf_len) |
| return; |
| |
| if (early) { |
| unsigned long mem; |
| |
| mem = memblock_alloc(new_log_buf_len, PAGE_SIZE); |
| if (!mem) |
| return; |
| new_log_buf = __va(mem); |
| } else { |
| new_log_buf = alloc_bootmem_nopanic(new_log_buf_len); |
| } |
| |
| if (unlikely(!new_log_buf)) { |
| pr_err("log_buf_len: %ld bytes not available\n", |
| new_log_buf_len); |
| return; |
| } |
| |
| raw_spin_lock_irqsave(&logbuf_lock, flags); |
| log_buf_len = new_log_buf_len; |
| log_buf = new_log_buf; |
| new_log_buf_len = 0; |
| free = __LOG_BUF_LEN - log_next_idx; |
| memcpy(log_buf, __log_buf, __LOG_BUF_LEN); |
| raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| |
| pr_info("log_buf_len: %d\n", log_buf_len); |
| pr_info("early log buf free: %d(%d%%)\n", |
| free, (free * 100) / __LOG_BUF_LEN); |
| } |
| |
| static bool __read_mostly ignore_loglevel; |
| |
| static int __init ignore_loglevel_setup(char *str) |
| { |
| ignore_loglevel = 1; |
| printk(KERN_INFO "debug: ignoring loglevel setting.\n"); |
| |
| return 0; |
| } |
| |
| early_param("ignore_loglevel", ignore_loglevel_setup); |
| module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to" |
| "print all kernel messages to the console."); |
| |
| #ifdef CONFIG_BOOT_PRINTK_DELAY |
| |
| static int boot_delay; /* msecs delay after each printk during bootup */ |
| static unsigned long long loops_per_msec; /* based on boot_delay */ |
| |
| static int __init boot_delay_setup(char *str) |
| { |
| unsigned long lpj; |
| |
| lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ |
| loops_per_msec = (unsigned long long)lpj / 1000 * HZ; |
| |
| get_option(&str, &boot_delay); |
| if (boot_delay > 10 * 1000) |
| boot_delay = 0; |
| |
| pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
| "HZ: %d, loops_per_msec: %llu\n", |
| boot_delay, preset_lpj, lpj, HZ, loops_per_msec); |
| return 1; |
| } |
| __setup("boot_delay=", boot_delay_setup); |
| |
| static void boot_delay_msec(int level) |
| { |
| unsigned long long k; |
| unsigned long timeout; |
| |
| if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) |
| || (level >= console_loglevel && !ignore_loglevel)) { |
| return; |
| } |
| |
| k = (unsigned long long)loops_per_msec * boot_delay; |
| |
| timeout = jiffies + msecs_to_jiffies(boot_delay); |
| while (k) { |
| k--; |
| cpu_relax(); |
| /* |
| * use (volatile) jiffies to prevent |
| * compiler reduction; loop termination via jiffies |
| * is secondary and may or may not happen. |
| */ |
| if (time_after(jiffies, timeout)) |
| break; |
| touch_nmi_watchdog(); |
| } |
| } |
| #else |
| static inline void boot_delay_msec(int level) |
| { |
| } |
| #endif |
| |
| #if defined(CONFIG_PRINTK_TIME) |
| static bool printk_time = 1; |
| #else |
| static bool printk_time; |
| #endif |
| module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
| |
| static size_t print_time(u64 ts, char *buf) |
| { |
| unsigned long rem_nsec; |
| |
| if (!printk_time) |
| return 0; |
| |
| rem_nsec = do_div(ts, 1000000000); |
| |
| if (!buf) |
| return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); |
| |
| return sprintf(buf, "[%5lu.%06lu] ", |
| (unsigned long)ts, rem_nsec / 1000); |
| } |
| |
| static size_t print_prefix(const struct log *msg, bool syslog, char *buf) |
| { |
| size_t len = 0; |
| unsigned int prefix = (msg->facility << 3) | msg->level; |
| |
| if (syslog) { |
| if (buf) { |
| len += sprintf(buf, "<%u>", prefix); |
| } else { |
| len += 3; |
| if (prefix > 999) |
| len += 3; |
| else if (prefix > 99) |
| len += 2; |
| else if (prefix > 9) |
| len++; |
| } |
| } |
| |
| len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
| return len; |
| } |
| |
| static size_t msg_print_text(const struct log *msg, enum log_flags prev, |
| bool syslog, char *buf, size_t size) |
| { |
| const char *text = log_text(msg); |
| size_t text_size = msg->text_len; |
| bool prefix = true; |
| bool newline = true; |
| size_t len = 0; |
| |
| if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) |
| prefix = false; |
| |
| if (msg->flags & LOG_CONT) { |
| if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) |
| prefix = false; |
| |
| if (!(msg->flags & LOG_NEWLINE)) |
| newline = false; |
| } |
| |
| do { |
| const char *next = memchr(text, '\n', text_size); |
| size_t text_len; |
| |
| if (next) { |
| text_len = next - text; |
| next++; |
| text_size -= next - text; |
| } else { |
| text_len = text_size; |
| } |
| |
| if (buf) { |
| if (print_prefix(msg, syslog, NULL) + |
| text_len + 1 >= size - len) |
| break; |
| |
| if (prefix) |
| len += print_prefix(msg, syslog, buf + len); |
| memcpy(buf + len, text, text_len); |
| len += text_len; |
| if (next || newline) |
| buf[len++] = '\n'; |
| } else { |
| /* SYSLOG_ACTION_* buffer size only calculation */ |
| if (prefix) |
| len += print_prefix(msg, syslog, NULL); |
| len += text_len; |
| if (next || newline) |
| len++; |
| } |
| |
| prefix = true; |
| text = next; |
| } while (text); |
| |
| return len; |
| } |
| |
| static int syslog_print(char __user *buf, int size) |
| { |
| char *text; |
| struct log *msg; |
| int len = 0; |
| |
| text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
| if (!text) |
| return -ENOMEM; |
| |
| while (size > 0) { |
| size_t n; |
| size_t skip; |
| |
| raw_spin_lock_irq(&logbuf_lock); |
| if (syslog_seq < log_first_seq) { |
| /* messages are gone, move to first one */ |
| syslog_seq = log_first_seq; |
| syslog_idx = log_first_idx; |
| syslog_prev = 0; |
| syslog_partial = 0; |
| } |
| if (syslog_seq == log_next_seq) { |
| raw_spin_unlock_irq(&logbuf_lock); |
| break; |
| } |
| |
| skip = syslog_partial; |
| msg = log_from_idx(syslog_idx); |
| n = msg_print_text(msg, syslog_prev, true, text, |
| LOG_LINE_MAX + PREFIX_MAX); |
| if (n - syslog_partial <= size) { |
| /* message fits into buffer, move forward */ |
| syslog_idx = log_next(syslog_idx); |
| syslog_seq++; |
| syslog_prev = msg->flags; |
| n -= syslog_partial; |
| syslog_partial = 0; |
| } else if (!len){ |
| /* partial read(), remember position */ |
| n = size; |
| syslog_partial += n; |
| } else |
| n = 0; |
| raw_spin_unlock_irq(&logbuf_lock); |
| |
| if (!n) |
| break; |
| |
| if (copy_to_user(buf, text + skip, n)) { |
| if (!len) |
| len = -EFAULT; |
| break; |
| } |
| |
| len += n; |
| size -= n; |
| buf += n; |
| } |
| |
| kfree(text); |
| return len; |
| } |
| |
| static int syslog_print_all(char __user *buf, int size, bool clear) |
| { |
| char *text; |
| int len = 0; |
| |
| text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
| if (!text) |
| return -ENOMEM; |
| |
| raw_spin_lock_irq(&logbuf_lock); |
| if (buf) { |
| u64 next_seq; |
| u64 seq; |
| u32 idx; |
| enum log_flags prev; |
| |
| if (clear_seq < log_first_seq) { |
| /* messages are gone, move to first available one */ |
| clear_seq = log_first_seq; |
| clear_idx = log_first_idx; |
| } |
| |
| /* |
| * Find first record that fits, including all following records, |
| * into the user-provided buffer for this dump. |
| */ |
| seq = clear_seq; |
| idx = clear_idx; |
| prev = 0; |
| while (seq < log_next_seq) { |
| struct log *msg = log_from_idx(idx); |
| |
| len += msg_print_text(msg, prev, true, NULL, 0); |
| prev = msg->flags; |
| idx = log_next(idx); |
| seq++; |
| } |
| |
| /* move first record forward until length fits into the buffer */ |
| seq = clear_seq; |
| idx = clear_idx; |
| prev = 0; |
| while (len > size && seq < log_next_seq) { |
| struct log *msg = log_from_idx(idx); |
| |
| len -= msg_print_text(msg, prev, true, NULL, 0); |
| prev = msg->flags; |
| idx = log_next(idx); |
| seq++; |
| } |
| |
| /* last message fitting into this dump */ |
| next_seq = log_next_seq; |
| |
| len = 0; |
| prev = 0; |
| while (len >= 0 && seq < next_seq) { |
| struct log *msg = log_from_idx(idx); |
| int textlen; |
| |
| textlen = msg_print_text(msg, prev, true, text, |
| LOG_LINE_MAX + PREFIX_MAX); |
| if (textlen < 0) { |
| len = textlen; |
| break; |
| } |
| idx = log_next(idx); |
| seq++; |
| prev = msg->flags; |
| |
| raw_spin_unlock_irq(&logbuf_lock); |
| if (copy_to_user(buf + len, text, textlen)) |
| len = -EFAULT; |
| else |
| len += textlen; |
| raw_spin_lock_irq(&logbuf_lock); |
| |
| if (seq < log_first_seq) { |
| /* messages are gone, move to next one */ |
| seq = log_first_seq; |
| idx = log_first_idx; |
| prev = 0; |
| } |
| } |
| } |
| |
| if (clear) { |
| clear_seq = log_next_seq; |
| clear_idx = log_next_idx; |
| } |
| raw_spin_unlock_irq(&logbuf_lock); |
| |
| kfree(text); |
| return len; |
| } |
| |
| int do_syslog(int type, char __user *buf, int len, bool from_file) |
| { |
| bool clear = false; |
| static int saved_console_loglevel = -1; |
| int error; |
| |
| error = check_syslog_permissions(type, from_file); |
| if (error) |
| goto out; |
| |
| error = security_syslog(type); |
| if (error) |
| return error; |
| |
| switch (type) { |
| case SYSLOG_ACTION_CLOSE: /* Close log */ |
| break; |
| case SYSLOG_ACTION_OPEN: /* Open log */ |
| break; |
| case SYSLOG_ACTION_READ: /* Read from log */ |
| error = -EINVAL; |
| if (!buf || len < 0) |
| goto out; |
| error = 0; |
| if (!len) |
| goto out; |
| if (!access_ok(VERIFY_WRITE, buf, len)) { |
| error = -EFAULT; |
| goto out; |
| } |
| error = wait_event_interruptible(log_wait, |
| syslog_seq != log_next_seq); |
| if (error) |
| goto out; |
| error = syslog_print(buf, len); |
| break; |
| /* Read/clear last kernel messages */ |
| case SYSLOG_ACTION_READ_CLEAR: |
| clear = true; |
| /* FALL THRU */ |
| /* Read last kernel messages */ |
| case SYSLOG_ACTION_READ_ALL: |
| error = -EINVAL; |
| if (!buf || len < 0) |
| goto out; |
| error = 0; |
| if (!len) |
| goto out; |
| if (!access_ok(VERIFY_WRITE, buf, len)) { |
| error = -EFAULT; |
| goto out; |
| } |
| error = syslog_print_all(buf, len, clear); |
| break; |
| /* Clear ring buffer */ |
| case SYSLOG_ACTION_CLEAR: |
| syslog_print_all(NULL, 0, true); |
| break; |
| /* Disable logging to console */ |
| case SYSLOG_ACTION_CONSOLE_OFF: |
| if (saved_console_loglevel == -1) |
| saved_console_loglevel = console_loglevel; |
| console_loglevel = minimum_console_loglevel; |
| break; |
| /* Enable logging to console */ |
| case SYSLOG_ACTION_CONSOLE_ON: |
| if (saved_console_loglevel != -1) { |
| console_loglevel = saved_console_loglevel; |
| saved_console_loglevel = -1; |
| } |
| break; |
| /* Set level of messages printed to console */ |
| case SYSLOG_ACTION_CONSOLE_LEVEL: |
| error = -EINVAL; |
| if (len < 1 || len > 8) |
| goto out; |
| if (len < minimum_console_loglevel) |
| len = minimum_console_loglevel; |
| console_loglevel = len; |
| /* Implicitly re-enable logging to console */ |
| saved_console_loglevel = -1; |
| error = 0; |
| break; |
| /* Number of chars in the log buffer */ |
| case SYSLOG_ACTION_SIZE_UNREAD: |
| raw_spin_lock_irq(&logbuf_lock); |
| if (syslog_seq < log_first_seq) { |
| /* messages are gone, move to first one */ |
| syslog_seq = log_first_seq; |
| syslog_idx = log_first_idx; |
| syslog_prev = 0; |
| syslog_partial = 0; |
| } |
| if (from_file) { |
| /* |
| * Short-cut for poll(/"proc/kmsg") which simply checks |
| * for pending data, not the size; return the count of |
| * records, not the length. |
| */ |
| error = log_next_idx - syslog_idx; |
| } else { |
| u64 seq = syslog_seq; |
| u32 idx = syslog_idx; |
| enum log_flags prev = syslog_prev; |
| |
| error = 0; |
| while (seq < log_next_seq) { |
| struct log *msg = log_from_idx(idx); |
| |
| error += msg_print_text(msg, prev, true, NULL, 0); |
| idx = log_next(idx); |
| seq++; |
| prev = msg->flags; |
| } |
| error -= syslog_partial; |
| } |
| raw_spin_unlock_irq(&logbuf_lock); |
| break; |
| /* Size of the log buffer */ |
| case SYSLOG_ACTION_SIZE_BUFFER: |
| error = log_buf_len; |
| break; |
| default: |
| error = -EINVAL; |
| break; |
| } |
| out: |
| return error; |
| } |
| |
| SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
| { |
| return do_syslog(type, buf, len, SYSLOG_FROM_READER); |
| } |
| |
| /* |
| * Call the console drivers, asking them to write out |
| * log_buf[start] to log_buf[end - 1]. |
| * The console_lock must be held. |
| */ |
| static void call_console_drivers(int level, const char *text, size_t len) |
| { |
| struct console *con; |
| |
| trace_console(text, len); |
| |
| if (level >= console_loglevel && !ignore_loglevel) |
| return; |
| if (!console_drivers) |
| return; |
| |
| for_each_console(con) { |
| if (exclusive_console && con != exclusive_console) |
| continue; |
| if (!(con->flags & CON_ENABLED)) |
| continue; |
| if (!con->write) |
| continue; |
| if (!cpu_online(smp_processor_id()) && |
| !(con->flags & CON_ANYTIME)) |
| continue; |
| con->write(con, text, len); |
| } |
| } |
| |
| /* |
| * Zap console related locks when oopsing. Only zap at most once |
| * every 10 seconds, to leave time for slow consoles to print a |
| * full oops. |
| */ |
| static void zap_locks(void) |
| { |
| static unsigned long oops_timestamp; |
| |
| if (time_after_eq(jiffies, oops_timestamp) && |
| !time_after(jiffies, oops_timestamp + 30 * HZ)) |
| return; |
| |
| oops_timestamp = jiffies; |
| |
| debug_locks_off(); |
| /* If a crash is occurring, make sure we can't deadlock */ |
| raw_spin_lock_init(&logbuf_lock); |
| /* And make sure that we print immediately */ |
| sema_init(&console_sem, 1); |
| } |
| |
| /* Check if we have any console registered that can be called early in boot. */ |
| static int have_callable_console(void) |
| { |
| struct console *con; |
| |
| for_each_console(con) |
| if (con->flags & CON_ANYTIME) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* |
| * Can we actually use the console at this time on this cpu? |
| * |
| * Console drivers may assume that per-cpu resources have |
| * been allocated. So unless they're explicitly marked as |
| * being able to cope (CON_ANYTIME) don't call them until |
| * this CPU is officially up. |
| */ |
| static inline int can_use_console(unsigned int cpu) |
| { |
| return cpu_online(cpu) || have_callable_console(); |
| } |
| |
| /* |
| * Try to get console ownership to actually show the kernel |
| * messages from a 'printk'. Return true (and with the |
| * console_lock held, and 'console_locked' set) if it |
| * is successful, false otherwise. |
| * |
| * This gets called with the 'logbuf_lock' spinlock held and |
| * interrupts disabled. It should return with 'lockbuf_lock' |
| * released but interrupts still disabled. |
| */ |
| static int console_trylock_for_printk(unsigned int cpu) |
| __releases(&logbuf_lock) |
| { |
| int retval = 0, wake = 0; |
| |
| if (console_trylock()) { |
| retval = 1; |
| |
| /* |
| * If we can't use the console, we need to release |
| * the console semaphore by hand to avoid flushing |
| * the buffer. We need to hold the console semaphore |
| * in order to do this test safely. |
| */ |
| if (!can_use_console(cpu)) { |
| console_locked = 0; |
| wake = 1; |
| retval = 0; |
| } |
| } |
| logbuf_cpu = UINT_MAX; |
| raw_spin_unlock(&logbuf_lock); |
| if (wake) |
| up(&console_sem); |
| return retval; |
| } |
| |
| int printk_delay_msec __read_mostly; |
| |
| static inline void printk_delay(void) |
| { |
| if (unlikely(printk_delay_msec)) { |
| int m = printk_delay_msec; |
| |
| while (m--) { |
| mdelay(1); |
| touch_nmi_watchdog(); |
| } |
| } |
| } |
| |
| /* |
| * Continuation lines are buffered, and not committed to the record buffer |
| * until the line is complete, or a race forces it. The line fragments |
| * though, are printed immediately to the consoles to ensure everything has |
| * reached the console in case of a kernel crash. |
| */ |
| static struct cont { |
| char buf[LOG_LINE_MAX]; |
| size_t len; /* length == 0 means unused buffer */ |
| size_t cons; /* bytes written to console */ |
| struct task_struct *owner; /* task of first print*/ |
| u64 ts_nsec; /* time of first print */ |
| u8 level; /* log level of first message */ |
| u8 facility; /* log level of first message */ |
| enum log_flags flags; /* prefix, newline flags */ |
| bool flushed:1; /* buffer sealed and committed */ |
| } cont; |
| |
| static void cont_flush(enum log_flags flags) |
| { |
| if (cont.flushed) |
| return; |
| if (cont.len == 0) |
| return; |
| |
| if (cont.cons) { |
| /* |
| * If a fragment of this line was directly flushed to the |
| * console; wait for the console to pick up the rest of the |
| * line. LOG_NOCONS suppresses a duplicated output. |
| */ |
| log_store(cont.facility, cont.level, flags | LOG_NOCONS, |
| cont.ts_nsec, NULL, 0, cont.buf, cont.len); |
| cont.flags = flags; |
| cont.flushed = true; |
| } else { |
| /* |
| * If no fragment of this line ever reached the console, |
| * just submit it to the store and free the buffer. |
| */ |
| log_store(cont.facility, cont.level, flags, 0, |
| NULL, 0, cont.buf, cont.len); |
| cont.len = 0; |
| } |
| } |
| |
| static bool cont_add(int facility, int level, const char *text, size_t len) |
| { |
| if (cont.len && cont.flushed) |
| return false; |
| |
| if (cont.len + len > sizeof(cont.buf)) { |
| /* the line gets too long, split it up in separate records */ |
| cont_flush(LOG_CONT); |
| return false; |
| } |
| |
| if (!cont.len) { |
| cont.facility = facility; |
| cont.level = level; |
| cont.owner = current; |
| cont.ts_nsec = local_clock(); |
| cont.flags = 0; |
| cont.cons = 0; |
| cont.flushed = false; |
| } |
| |
| memcpy(cont.buf + cont.len, text, len); |
| cont.len += len; |
| |
| if (cont.len > (sizeof(cont.buf) * 80) / 100) |
| cont_flush(LOG_CONT); |
| |
| return true; |
| } |
| |
| static size_t cont_print_text(char *text, size_t size) |
| { |
| size_t textlen = 0; |
| size_t len; |
| |
| if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) { |
| textlen += print_time(cont.ts_nsec, text); |
| size -= textlen; |
| } |
| |
| len = cont.len - cont.cons; |
| if (len > 0) { |
| if (len+1 > size) |
| len = size-1; |
| memcpy(text + textlen, cont.buf + cont.cons, len); |
| textlen += len; |
| cont.cons = cont.len; |
| } |
| |
| if (cont.flushed) { |
| if (cont.flags & LOG_NEWLINE) |
| text[textlen++] = '\n'; |
| /* got everything, release buffer */ |
| cont.len = 0; |
| } |
| return textlen; |
| } |
| |
| asmlinkage int vprintk_emit(int facility, int level, |
| const char *dict, size_t dictlen, |
| const char *fmt, va_list args) |
| { |
| static int recursion_bug; |
| static char textbuf[LOG_LINE_MAX]; |
| char *text = textbuf; |
| size_t text_len; |
| enum log_flags lflags = 0; |
| unsigned long flags; |
| int this_cpu; |
| int printed_len = 0; |
| |
| boot_delay_msec(level); |
| printk_delay(); |
| |
| /* This stops the holder of console_sem just where we want him */ |
| local_irq_save(flags); |
| this_cpu = smp_processor_id(); |
| |
| /* |
| * Ouch, printk recursed into itself! |
| */ |
| if (unlikely(logbuf_cpu == this_cpu)) { |
| /* |
| * If a crash is occurring during printk() on this CPU, |
| * then try to get the crash message out but make sure |
| * we can't deadlock. Otherwise just return to avoid the |
| * recursion and return - but flag the recursion so that |
| * it can be printed at the next appropriate moment: |
| */ |
| if (!oops_in_progress && !lockdep_recursing(current)) { |
| recursion_bug = 1; |
| goto out_restore_irqs; |
| } |
| zap_locks(); |
| } |
| |
| lockdep_off(); |
| raw_spin_lock(&logbuf_lock); |
| logbuf_cpu = this_cpu; |
| |
| if (recursion_bug) { |
| static const char recursion_msg[] = |
| "BUG: recent printk recursion!"; |
| |
| recursion_bug = 0; |
| printed_len += strlen(recursion_msg); |
| /* emit KERN_CRIT message */ |
| log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
| NULL, 0, recursion_msg, printed_len); |
| } |
| |
| /* |
| * The printf needs to come first; we need the syslog |
| * prefix which might be passed-in as a parameter. |
| */ |
| text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
| |
| /* mark and strip a trailing newline */ |
| if (text_len && text[text_len-1] == '\n') { |
| text_len--; |
| lflags |= LOG_NEWLINE; |
| } |
| |
| /* strip kernel syslog prefix and extract log level or control flags */ |
| if (facility == 0) { |
| int kern_level = printk_get_level(text); |
| |
| if (kern_level) { |
| const char *end_of_header = printk_skip_level(text); |
| switch (kern_level) { |
| case '0' ... '7': |
| if (level == -1) |
| level = kern_level - '0'; |
| case 'd': /* KERN_DEFAULT */ |
| lflags |= LOG_PREFIX; |
| case 'c': /* KERN_CONT */ |
| break; |
| } |
| text_len -= end_of_header - text; |
| text = (char *)end_of_header; |
| } |
| } |
| |
| if (level == -1) |
| level = default_message_loglevel; |
| |
| if (dict) |
| lflags |= LOG_PREFIX|LOG_NEWLINE; |
| |
| if (!(lflags & LOG_NEWLINE)) { |
| /* |
| * Flush the conflicting buffer. An earlier newline was missing, |
| * or another task also prints continuation lines. |
| */ |
| if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) |
| cont_flush(LOG_NEWLINE); |
| |
| /* buffer line if possible, otherwise store it right away */ |
| if (!cont_add(facility, level, text, text_len)) |
| log_store(facility, level, lflags | LOG_CONT, 0, |
| dict, dictlen, text, text_len); |
| } else { |
| bool stored = false; |
| |
| /* |
| * If an earlier newline was missing and it was the same task, |
| * either merge it with the current buffer and flush, or if |
| * there was a race with interrupts (prefix == true) then just |
| * flush it out and store this line separately. |
| */ |
| if (cont.len && cont.owner == current) { |
| if (!(lflags & LOG_PREFIX)) |
| stored = cont_add(facility, level, text, text_len); |
| cont_flush(LOG_NEWLINE); |
| } |
| |
| if (!stored) |
| log_store(facility, level, lflags, 0, |
| dict, dictlen, text, text_len); |
| } |
| printed_len += text_len; |
| |
| /* |
| * Try to acquire and then immediately release the console semaphore. |
| * The release will print out buffers and wake up /dev/kmsg and syslog() |
| * users. |
| * |
| * The console_trylock_for_printk() function will release 'logbuf_lock' |
| * regardless of whether it actually gets the console semaphore or not. |
| */ |
| if (console_trylock_for_printk(this_cpu)) |
| console_unlock(); |
| |
| lockdep_on(); |
| out_restore_irqs: |
| local_irq_restore(flags); |
| |
| return printed_len; |
| } |
| EXPORT_SYMBOL(vprintk_emit); |
| |
| asmlinkage int vprintk(const char *fmt, va_list args) |
| { |
| return vprintk_emit(0, -1, NULL, 0, fmt, args); |
| } |
| EXPORT_SYMBOL(vprintk); |
| |
| asmlinkage int printk_emit(int facility, int level, |
| const char *dict, size_t dictlen, |
| const char *fmt, ...) |
| { |
| va_list args; |
| int r; |
| |
| va_start(args, fmt); |
| r = vprintk_emit(facility, level, dict, dictlen, fmt, args); |
| va_end(args); |
| |
| return r; |
| } |
| EXPORT_SYMBOL(printk_emit); |
| |
| /** |
| * printk - print a kernel message |
| * @fmt: format string |
| * |
| * This is printk(). It can be called from any context. We want it to work. |
| * |
| * We try to grab the console_lock. If we succeed, it's easy - we log the |
| * output and call the console drivers. If we fail to get the semaphore, we |
| * place the output into the log buffer and return. The current holder of |
| * the console_sem will notice the new output in console_unlock(); and will |
| * send it to the consoles before releasing the lock. |
| * |
| * One effect of this deferred printing is that code which calls printk() and |
| * then changes console_loglevel may break. This is because console_loglevel |
| * is inspected when the actual printing occurs. |
| * |
| * See also: |
| * printf(3) |
| * |
| * See the vsnprintf() documentation for format string extensions over C99. |
| */ |
| asmlinkage int printk(const char *fmt, ...) |
| { |
| va_list args; |
| int r; |
| |
| #ifdef CONFIG_KGDB_KDB |
| if (unlikely(kdb_trap_printk)) { |
| va_start(args, fmt); |
| r = vkdb_printf(fmt, args); |
| va_end(args); |
| return r; |
| } |
| #endif |
| va_start(args, fmt); |
| r = vprintk_emit(0, -1, NULL, 0, fmt, args); |
| va_end(args); |
| |
| return r; |
| } |
| EXPORT_SYMBOL(printk); |
| |
| #else /* CONFIG_PRINTK */ |
| |
| #define LOG_LINE_MAX 0 |
| #define PREFIX_MAX 0 |
| #define LOG_LINE_MAX 0 |
| static u64 syslog_seq; |
| static u32 syslog_idx; |
| static u64 console_seq; |
| static u32 console_idx; |
| static enum log_flags syslog_prev; |
| static u64 log_first_seq; |
| static u32 log_first_idx; |
| static u64 log_next_seq; |
| static enum log_flags console_prev; |
| static struct cont { |
| size_t len; |
| size_t cons; |
| u8 level; |
| bool flushed:1; |
| } cont; |
| static struct log *log_from_idx(u32 idx) { return NULL; } |
| static u32 log_next(u32 idx) { return 0; } |
| static void call_console_drivers(int level, const char *text, size_t len) {} |
| static size_t msg_print_text(const struct log *msg, enum log_flags prev, |
| bool syslog, char *buf, size_t size) { return 0; } |
| static size_t cont_print_text(char *text, size_t size) { return 0; } |
| |
| #endif /* CONFIG_PRINTK */ |
| |
| #ifdef CONFIG_EARLY_PRINTK |
| struct console *early_console; |
| |
| void early_vprintk(const char *fmt, va_list ap) |
| { |
| if (early_console) { |
| char buf[512]; |
| int n = vscnprintf(buf, sizeof(buf), fmt, ap); |
| |
| early_console->write(early_console, buf, n); |
| } |
| } |
| |
| asmlinkage void early_printk(const char *fmt, ...) |
| { |
| va_list ap; |
| |
| va_start(ap, fmt); |
| early_vprintk(fmt, ap); |
| va_end(ap); |
| } |
| #endif |
| |
| static int __add_preferred_console(char *name, int idx, char *options, |
| char *brl_options) |
| { |
| struct console_cmdline *c; |
| int i; |
| |
| /* |
| * See if this tty is not yet registered, and |
| * if we have a slot free. |
| */ |
| for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) |
| if (strcmp(console_cmdline[i].name, name) == 0 && |
| console_cmdline[i].index == idx) { |
| if (!brl_options) |
| selected_console = i; |
| return 0; |
| } |
| if (i == MAX_CMDLINECONSOLES) |
| return -E2BIG; |
| if (!brl_options) |
| selected_console = i; |
| c = &console_cmdline[i]; |
| strlcpy(c->name, name, sizeof(c->name)); |
| c->options = options; |
| #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| c->brl_options = brl_options; |
| #endif |
| c->index = idx; |
| return 0; |
| } |
| /* |
| * Set up a list of consoles. Called from init/main.c |
| */ |
| static int __init console_setup(char *str) |
| { |
| char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
| char *s, *options, *brl_options = NULL; |
| int idx; |
| |
| #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| if (!memcmp(str, "brl,", 4)) { |
| brl_options = ""; |
| str += 4; |
| } else if (!memcmp(str, "brl=", 4)) { |
| brl_options = str + 4; |
| str = strchr(brl_options, ','); |
| if (!str) { |
| printk(KERN_ERR "need port name after brl=\n"); |
| return 1; |
| } |
| *(str++) = 0; |
| } |
| #endif |
| |
| /* |
| * Decode str into name, index, options. |
| */ |
| if (str[0] >= '0' && str[0] <= '9') { |
| strcpy(buf, "ttyS"); |
| strncpy(buf + 4, str, sizeof(buf) - 5); |
| } else { |
| strncpy(buf, str, sizeof(buf) - 1); |
| } |
| buf[sizeof(buf) - 1] = 0; |
| if ((options = strchr(str, ',')) != NULL) |
| *(options++) = 0; |
| #ifdef __sparc__ |
| if (!strcmp(str, "ttya")) |
| strcpy(buf, "ttyS0"); |
| if (!strcmp(str, "ttyb")) |
| strcpy(buf, "ttyS1"); |
| #endif |
| for (s = buf; *s; s++) |
| if ((*s >= '0' && *s <= '9') || *s == ',') |
| break; |
| idx = simple_strtoul(s, NULL, 10); |
| *s = 0; |
| |
| __add_preferred_console(buf, idx, options, brl_options); |
| console_set_on_cmdline = 1; |
| return 1; |
| } |
| __setup("console=", console_setup); |
| |
| /** |
| * add_preferred_console - add a device to the list of preferred consoles. |
| * @name: device name |
| * @idx: device index |
| * @options: options for this console |
| * |
| * The last preferred console added will be used for kernel messages |
| * and stdin/out/err for init. Normally this is used by console_setup |
| * above to handle user-supplied console arguments; however it can also |
| * be used by arch-specific code either to override the user or more |
| * commonly to provide a default console (ie from PROM variables) when |
| * the user has not supplied one. |
| */ |
| int add_preferred_console(char *name, int idx, char *options) |
| { |
| return __add_preferred_console(name, idx, options, NULL); |
| } |
| |
| int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
| { |
| struct console_cmdline *c; |
| int i; |
| |
| for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) |
| if (strcmp(console_cmdline[i].name, name) == 0 && |
| console_cmdline[i].index == idx) { |
| c = &console_cmdline[i]; |
| strlcpy(c->name, name_new, sizeof(c->name)); |
| c->name[sizeof(c->name) - 1] = 0; |
| c->options = options; |
| c->index = idx_new; |
| return i; |
| } |
| /* not found */ |
| return -1; |
| } |
| |
| bool console_suspend_enabled = 1; |
| EXPORT_SYMBOL(console_suspend_enabled); |
| |
| static int __init console_suspend_disable(char *str) |
| { |
| console_suspend_enabled = 0; |
| return 1; |
| } |
| __setup("no_console_suspend", console_suspend_disable); |
| module_param_named(console_suspend, console_suspend_enabled, |
| bool, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(console_suspend, "suspend console during suspend" |
| " and hibernate operations"); |
| |
| /** |
| * suspend_console - suspend the console subsystem |
| * |
| * This disables printk() while we go into suspend states |
| */ |
| void suspend_console(void) |
| { |
| if (!console_suspend_enabled) |
| return; |
| printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
| console_lock(); |
| console_suspended = 1; |
| up(&console_sem); |
| } |
| |
| void resume_console(void) |
| { |
| if (!console_suspend_enabled) |
| return; |
| down(&console_sem); |
| console_suspended = 0; |
| console_unlock(); |
| } |
| |
| /** |
| * console_cpu_notify - print deferred console messages after CPU hotplug |
| * @self: notifier struct |
| * @action: CPU hotplug event |
| * @hcpu: unused |
| * |
| * If printk() is called from a CPU that is not online yet, the messages |
| * will be spooled but will not show up on the console. This function is |
| * called when a new CPU comes online (or fails to come up), and ensures |
| * that any such output gets printed. |
| */ |
| static int __cpuinit console_cpu_notify(struct notifier_block *self, |
| unsigned long action, void *hcpu) |
| { |
| switch (action) { |
| case CPU_ONLINE: |
| case CPU_DEAD: |
| case CPU_DOWN_FAILED: |
| case CPU_UP_CANCELED: |
| console_lock(); |
| console_unlock(); |
| } |
| return NOTIFY_OK; |
| } |
| |
| /** |
| * console_lock - lock the console system for exclusive use. |
| * |
| * Acquires a lock which guarantees that the caller has |
| * exclusive access to the console system and the console_drivers list. |
| * |
| * Can sleep, returns nothing. |
| */ |
| void console_lock(void) |
| { |
| might_sleep(); |
| |
| down(&console_sem); |
| if (console_suspended) |
| return; |
| console_locked = 1; |
| console_may_schedule = 1; |
| mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_); |
| } |
| EXPORT_SYMBOL(console_lock); |
| |
| /** |
| * console_trylock - try to lock the console system for exclusive use. |
| * |
| * Tried to acquire a lock which guarantees that the caller has |
| * exclusive access to the console system and the console_drivers list. |
| * |
| * returns 1 on success, and 0 on failure to acquire the lock. |
| */ |
| int console_trylock(void) |
| { |
| if (down_trylock(&console_sem)) |
| return 0; |
| if (console_suspended) { |
| up(&console_sem); |
| return 0; |
| } |
| console_locked = 1; |
| console_may_schedule = 0; |
| mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_); |
| return 1; |
| } |
| EXPORT_SYMBOL(console_trylock); |
| |
| int is_console_locked(void) |
| { |
| return console_locked; |
| } |
| |
| static void console_cont_flush(char *text, size_t size) |
| { |
| unsigned long flags; |
| size_t len; |
| |
| raw_spin_lock_irqsave(&logbuf_lock, flags); |
| |
| if (!cont.len) |
| goto out; |
| |
| /* |
| * We still queue earlier records, likely because the console was |
| * busy. The earlier ones need to be printed before this one, we |
| * did not flush any fragment so far, so just let it queue up. |
| */ |
| if (console_seq < log_next_seq && !cont.cons) |
| goto out; |
| |
| len = cont_print_text(text, size); |
| raw_spin_unlock(&logbuf_lock); |
| stop_critical_timings(); |
| call_console_drivers(cont.level, text, len); |
| start_critical_timings(); |
| local_irq_restore(flags); |
| return; |
| out: |
| raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| } |
| |
| /** |
| * console_unlock - unlock the console system |
| * |
| * Releases the console_lock which the caller holds on the console system |
| * and the console driver list. |
| * |
| * While the console_lock was held, console output may have been buffered |
| * by printk(). If this is the case, console_unlock(); emits |
| * the output prior to releasing the lock. |
| * |
| * If there is output waiting, we wake /dev/kmsg and syslog() users. |
| * |
| * console_unlock(); may be called from any context. |
| */ |
| void console_unlock(void) |
| { |
| static char text[LOG_LINE_MAX + PREFIX_MAX]; |
| static u64 seen_seq; |
| unsigned long flags; |
| bool wake_klogd = false; |
| bool retry; |
| |
| if (console_suspended) { |
| up(&console_sem); |
| return; |
| } |
| |
| console_may_schedule = 0; |
| |
| /* flush buffered message fragment immediately to console */ |
| console_cont_flush(text, sizeof(text)); |
| again: |
| for (;;) { |
| struct log *msg; |
| size_t len; |
| int level; |
| |
| raw_spin_lock_irqsave(&logbuf_lock, flags); |
| if (seen_seq != log_next_seq) { |
| wake_klogd = true; |
| seen_seq = log_next_seq; |
| } |
| |
| if (console_seq < log_first_seq) { |
| /* messages are gone, move to first one */ |
| console_seq = log_first_seq; |
| console_idx = log_first_idx; |
| console_prev = 0; |
| } |
| skip: |
| if (console_seq == log_next_seq) |
| break; |
| |
| msg = log_from_idx(console_idx); |
| if (msg->flags & LOG_NOCONS) { |
| /* |
| * Skip record we have buffered and already printed |
| * directly to the console when we received it. |
| */ |
| console_idx = log_next(console_idx); |
| console_seq++; |
| /* |
| * We will get here again when we register a new |
| * CON_PRINTBUFFER console. Clear the flag so we |
| * will properly dump everything later. |
| */ |
| msg->flags &= ~LOG_NOCONS; |
| console_prev = msg->flags; |
| goto skip; |
| } |
| |
| level = msg->level; |
| len = msg_print_text(msg, console_prev, false, |
| text, sizeof(text)); |
| console_idx = log_next(console_idx); |
| console_seq++; |
| console_prev = msg->flags; |
| raw_spin_unlock(&logbuf_lock); |
| |
| stop_critical_timings(); /* don't trace print latency */ |
| call_console_drivers(level, text, len); |
| start_critical_timings(); |
| local_irq_restore(flags); |
| } |
| console_locked = 0; |
| mutex_release(&console_lock_dep_map, 1, _RET_IP_); |
| |
| /* Release the exclusive_console once it is used */ |
| if (unlikely(exclusive_console)) |
| exclusive_console = NULL; |
| |
| raw_spin_unlock(&logbuf_lock); |
| |
| up(&console_sem); |
| |
| /* |
| * Someone could have filled up the buffer again, so re-check if there's |
| * something to flush. In case we cannot trylock the console_sem again, |
| * there's a new owner and the console_unlock() from them will do the |
| * flush, no worries. |
| */ |
| raw_spin_lock(&logbuf_lock); |
| retry = console_seq != log_next_seq; |
| raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| |
| if (retry && console_trylock()) |
| goto again; |
| |
| if (wake_klogd) |
| wake_up_klogd(); |
| } |
| EXPORT_SYMBOL(console_unlock); |
| |
| /** |
| * console_conditional_schedule - yield the CPU if required |
| * |
| * If the console code is currently allowed to sleep, and |
| * if this CPU should yield the CPU to another task, do |
| * so here. |
| * |
| * Must be called within console_lock();. |
| */ |
| void __sched console_conditional_schedule(void) |
| { |
| if (console_may_schedule) |
| cond_resched(); |
| } |
| EXPORT_SYMBOL(console_conditional_schedule); |
| |
| void console_unblank(void) |
| { |
| struct console *c; |
| |
| /* |
| * console_unblank can no longer be called in interrupt context unless |
| * oops_in_progress is set to 1.. |
| */ |
| if (oops_in_progress) { |
| if (down_trylock(&console_sem) != 0) |
| return; |
| } else |
| console_lock(); |
| |
| console_locked = 1; |
| console_may_schedule = 0; |
| for_each_console(c) |
| if ((c->flags & CON_ENABLED) && c->unblank) |
| c->unblank(); |
| console_unlock(); |
| } |
| |
| /* |
| * Return the console tty driver structure and its associated index |
| */ |
| struct tty_driver *console_device(int *index) |
| { |
| struct console *c; |
| struct tty_driver *driver = NULL; |
| |
| console_lock(); |
| for_each_console(c) { |
| if (!c->device) |
| continue; |
| driver = c->device(c, index); |
| if (driver) |
| break; |
| } |
| console_unlock(); |
| return driver; |
| } |
| |
| /* |
| * Prevent further output on the passed console device so that (for example) |
| * serial drivers can disable console output before suspending a port, and can |
| * re-enable output afterwards. |
| */ |
| void console_stop(struct console *console) |
| { |
| console_lock(); |
| console->flags &= ~CON_ENABLED; |
| console_unlock(); |
| } |
| EXPORT_SYMBOL(console_stop); |
| |
| void console_start(struct console *console) |
| { |
| console_lock(); |
| console->flags |= CON_ENABLED; |
| console_unlock(); |
| } |
| EXPORT_SYMBOL(console_start); |
| |
| static int __read_mostly keep_bootcon; |
| |
| static int __init keep_bootcon_setup(char *str) |
| { |
| keep_bootcon = 1; |
| printk(KERN_INFO "debug: skip boot console de-registration.\n"); |
| |
| return 0; |
| } |
| |
| early_param("keep_bootcon", keep_bootcon_setup); |
| |
| /* |
| * The console driver calls this routine during kernel initialization |
| * to register the console printing procedure with printk() and to |
| * print any messages that were printed by the kernel before the |
| * console driver was initialized. |
| * |
| * This can happen pretty early during the boot process (because of |
| * early_printk) - sometimes before setup_arch() completes - be careful |
| * of what kernel features are used - they may not be initialised yet. |
| * |
| * There are two types of consoles - bootconsoles (early_printk) and |
| * "real" consoles (everything which is not a bootconsole) which are |
| * handled differently. |
| * - Any number of bootconsoles can be registered at any time. |
| * - As soon as a "real" console is registered, all bootconsoles |
| * will be unregistered automatically. |
| * - Once a "real" console is registered, any attempt to register a |
| * bootconsoles will be rejected |
| */ |
| void register_console(struct console *newcon) |
| { |
| int i; |
| unsigned long flags; |
| struct console *bcon = NULL; |
| |
| /* |
| * before we register a new CON_BOOT console, make sure we don't |
| * already have a valid console |
| */ |
| if (console_drivers && newcon->flags & CON_BOOT) { |
| /* find the last or real console */ |
| for_each_console(bcon) { |
| if (!(bcon->flags & CON_BOOT)) { |
| printk(KERN_INFO "Too late to register bootconsole %s%d\n", |
| newcon->name, newcon->index); |
| return; |
| } |
| } |
| } |
| |
| if (console_drivers && console_drivers->flags & CON_BOOT) |
| bcon = console_drivers; |
| |
| if (preferred_console < 0 || bcon || !console_drivers) |
| preferred_console = selected_console; |
| |
| if (newcon->early_setup) |
| newcon->early_setup(); |
| |
| /* |
| * See if we want to use this console driver. If we |
| * didn't select a console we take the first one |
| * that registers here. |
| */ |
| if (preferred_console < 0) { |
| if (newcon->index < 0) |
| newcon->index = 0; |
| if (newcon->setup == NULL || |
| newcon->setup(newcon, NULL) == 0) { |
| newcon->flags |= CON_ENABLED; |
| if (newcon->device) { |
| newcon->flags |= CON_CONSDEV; |
| preferred_console = 0; |
| } |
| } |
| } |
| |
| /* |
| * See if this console matches one we selected on |
| * the command line. |
| */ |
| for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; |
| i++) { |
| if (strcmp(console_cmdline[i].name, newcon->name) != 0) |
| continue; |
| if (newcon->index >= 0 && |
| newcon->index != console_cmdline[i].index) |
| continue; |
| if (newcon->index < 0) |
| newcon->index = console_cmdline[i].index; |
| #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| if (console_cmdline[i].brl_options) { |
| newcon->flags |= CON_BRL; |
| braille_register_console(newcon, |
| console_cmdline[i].index, |
| console_cmdline[i].options, |
| console_cmdline[i].brl_options); |
| return; |
| } |
| #endif |
| if (newcon->setup && |
| newcon->setup(newcon, console_cmdline[i].options) != 0) |
| break; |
| newcon->flags |= CON_ENABLED; |
| newcon->index = console_cmdline[i].index; |
| if (i == selected_console) { |
| newcon->flags |= CON_CONSDEV; |
| preferred_console = selected_console; |
| } |
| break; |
| } |
| |
| if (!(newcon->flags & CON_ENABLED)) |
| return; |
| |
| /* |
| * If we have a bootconsole, and are switching to a real console, |
| * don't print everything out again, since when the boot console, and |
| * the real console are the same physical device, it's annoying to |
| * see the beginning boot messages twice |
| */ |
| if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) |
| newcon->flags &= ~CON_PRINTBUFFER; |
| |
| /* |
| * Put this console in the list - keep the |
| * preferred driver at the head of the list. |
| */ |
| console_lock(); |
| if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
| newcon->next = console_drivers; |
| console_drivers = newcon; |
| if (newcon->next) |
| newcon->next->flags &= ~CON_CONSDEV; |
| } else { |
| newcon->next = console_drivers->next; |
| console_drivers->next = newcon; |
| } |
| if (newcon->flags & CON_PRINTBUFFER) { |
| /* |
| * console_unlock(); will print out the buffered messages |
| * for us. |
| */ |
| raw_spin_lock_irqsave(&logbuf_lock, flags); |
| console_seq = syslog_seq; |
| console_idx = syslog_idx; |
| console_prev = syslog_prev; |
| raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| /* |
| * We're about to replay the log buffer. Only do this to the |
| * just-registered console to avoid excessive message spam to |
| * the already-registered consoles. |
| */ |
| exclusive_console = newcon; |
| } |
| console_unlock(); |
| console_sysfs_notify(); |
| |
| /* |
| * By unregistering the bootconsoles after we enable the real console |
| * we get the "console xxx enabled" message on all the consoles - |
| * boot consoles, real consoles, etc - this is to ensure that end |
| * users know there might be something in the kernel's log buffer that |
| * went to the bootconsole (that they do not see on the real console) |
| */ |
| if (bcon && |
| ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && |
| !keep_bootcon) { |
| /* we need to iterate through twice, to make sure we print |
| * everything out, before we unregister the console(s) |
| */ |
| printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n", |
| newcon->name, newcon->index); |
| for_each_console(bcon) |
| if (bcon->flags & CON_BOOT) |
| unregister_console(bcon); |
| } else { |
| printk(KERN_INFO "%sconsole [%s%d] enabled\n", |
| (newcon->flags & CON_BOOT) ? "boot" : "" , |
| newcon->name, newcon->index); |
| } |
| } |
| EXPORT_SYMBOL(register_console); |
| |
| int unregister_console(struct console *console) |
| { |
| struct console *a, *b; |
| int res = 1; |
| |
| #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| if (console->flags & CON_BRL) |
| return braille_unregister_console(console); |
| #endif |
| |
| console_lock(); |
| if (console_drivers == console) { |
| console_drivers=console->next; |
| res = 0; |
| } else if (console_drivers) { |
| for (a=console_drivers->next, b=console_drivers ; |
| a; b=a, a=b->next) { |
| if (a == console) { |
| b->next = a->next; |
| res = 0; |
| break; |
| } |
| } |
| } |
| |
| /* |
| * If this isn't the last console and it has CON_CONSDEV set, we |
| * need to set it on the next preferred console. |
| */ |
| if (console_drivers != NULL && console->flags & CON_CONSDEV) |
| console_drivers->flags |= CON_CONSDEV; |
| |
| console_unlock(); |
| console_sysfs_notify(); |
| return res; |
| } |
| EXPORT_SYMBOL(unregister_console); |
| |
| static int __init printk_late_init(void) |
| { |
| struct console *con; |
| |
| for_each_console(con) { |
| if (!keep_bootcon && con->flags & CON_BOOT) { |
| printk(KERN_INFO "turn off boot console %s%d\n", |
| con->name, con->index); |
| unregister_console(con); |
| } |
| } |
| hotcpu_notifier(console_cpu_notify, 0); |
| return 0; |
| } |
| late_initcall(printk_late_init); |
| |
| #if defined CONFIG_PRINTK |
| /* |
| * Delayed printk version, for scheduler-internal messages: |
| */ |
| #define PRINTK_BUF_SIZE 512 |
| |
| #define PRINTK_PENDING_WAKEUP 0x01 |
| #define PRINTK_PENDING_SCHED 0x02 |
| |
| static DEFINE_PER_CPU(int, printk_pending); |
| static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); |
| |
| static void wake_up_klogd_work_func(struct irq_work *irq_work) |
| { |
| int pending = __this_cpu_xchg(printk_pending, 0); |
| |
| if (pending & PRINTK_PENDING_SCHED) { |
| char *buf = __get_cpu_var(printk_sched_buf); |
| printk(KERN_WARNING "[sched_delayed] %s", buf); |
| } |
| |
| if (pending & PRINTK_PENDING_WAKEUP) |
| wake_up_interruptible(&log_wait); |
| } |
| |
| static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { |
| .func = wake_up_klogd_work_func, |
| .flags = IRQ_WORK_LAZY, |
| }; |
| |
| void wake_up_klogd(void) |
| { |
| preempt_disable(); |
| if (waitqueue_active(&log_wait)) { |
| this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); |
| irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); |
| } |
| preempt_enable(); |
| } |
| |
| int printk_deferred(const char *fmt, ...) |
| { |
| unsigned long flags; |
| va_list args; |
| char *buf; |
| int r; |
| |
| local_irq_save(flags); |
| buf = __get_cpu_var(printk_sched_buf); |
| |
| va_start(args, fmt); |
| r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args); |
| va_end(args); |
| |
| __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED); |
| irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); |
| local_irq_restore(flags); |
| |
| return r; |
| } |
| |
| /* |
| * printk rate limiting, lifted from the networking subsystem. |
| * |
| * This enforces a rate limit: not more than 10 kernel messages |
| * every 5s to make a denial-of-service attack impossible. |
| */ |
| DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
| |
| int __printk_ratelimit(const char *func) |
| { |
| return ___ratelimit(&printk_ratelimit_state, func); |
| } |
| EXPORT_SYMBOL(__printk_ratelimit); |
| |
| /** |
| * printk_timed_ratelimit - caller-controlled printk ratelimiting |
| * @caller_jiffies: pointer to caller's state |
| * @interval_msecs: minimum interval between prints |
| * |
| * printk_timed_ratelimit() returns true if more than @interval_msecs |
| * milliseconds have elapsed since the last time printk_timed_ratelimit() |
| * returned true. |
| */ |
| bool printk_timed_ratelimit(unsigned long *caller_jiffies, |
| unsigned int interval_msecs) |
| { |
| if (*caller_jiffies == 0 |
| || !time_in_range(jiffies, *caller_jiffies, |
| *caller_jiffies |
| + msecs_to_jiffies(interval_msecs))) { |
| *caller_jiffies = jiffies; |
| return true; |
| } |
| return false; |
| } |
| EXPORT_SYMBOL(printk_timed_ratelimit); |
| |
| static DEFINE_SPINLOCK(dump_list_lock); |
| static LIST_HEAD(dump_list); |
| |
| /** |
| * kmsg_dump_register - register a kernel log dumper. |
| * @dumper: pointer to the kmsg_dumper structure |
| * |
| * Adds a kernel log dumper to the system. The dump callback in the |
| * structure will be called when the kernel oopses or panics and must be |
| * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. |
| */ |
| int kmsg_dump_register(struct kmsg_dumper *dumper) |
| { |
| unsigned long flags; |
| int err = -EBUSY; |
| |
| /* The dump callback needs to be set */ |
| if (!dumper->dump) |
| return -EINVAL; |
| |
| spin_lock_irqsave(&dump_list_lock, flags); |
| /* Don't allow registering multiple times */ |
| if (!dumper->registered) { |
| dumper->registered = 1; |
| list_add_tail_rcu(&dumper->list, &dump_list); |
| err = 0; |
| } |
| spin_unlock_irqrestore(&dump_list_lock, flags); |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(kmsg_dump_register); |
| |
| /** |
| * kmsg_dump_unregister - unregister a kmsg dumper. |
| * @dumper: pointer to the kmsg_dumper structure |
| * |
| * Removes a dump device from the system. Returns zero on success and |
| * %-EINVAL otherwise. |
| */ |
| int kmsg_dump_unregister(struct kmsg_dumper *dumper) |
| { |
| unsigned long flags; |
| int err = -EINVAL; |
| |
| spin_lock_irqsave(&dump_list_lock, flags); |
| if (dumper->registered) { |
| dumper->registered = 0; |
| list_del_rcu(&dumper->list); |
| err = 0; |
| } |
| spin_unlock_irqrestore(&dump_list_lock, flags); |
| synchronize_rcu(); |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(kmsg_dump_unregister); |
| |
| static bool always_kmsg_dump; |
| module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); |
| |
| /** |
| * kmsg_dump - dump kernel log to kernel message dumpers. |
| * @reason: the reason (oops, panic etc) for dumping |
| * |
| * Call each of the registered dumper's dump() callback, which can |
| * retrieve the kmsg records with kmsg_dump_get_line() or |
| * kmsg_dump_get_buffer(). |
| */ |
| void kmsg_dump(enum kmsg_dump_reason reason) |
| { |
| struct kmsg_dumper *dumper; |
| unsigned long flags; |
| |
| if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
| return; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(dumper, &dump_list, list) { |
| if (dumper->max_reason && reason > dumper->max_reason) |
| continue; |
| |
| /* initialize iterator with data about the stored records */ |
| dumper->active = true; |
| |
| raw_spin_lock_irqsave(&logbuf_lock, flags); |
| dumper->cur_seq = clear_seq; |
| dumper->cur_idx = clear_idx; |
| dumper->next_seq = log_next_seq; |
| dumper->next_idx = log_next_idx; |
| raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| |
| /* invoke dumper which will iterate over records */ |
| dumper->dump(dumper, reason); |
| |
| /* reset iterator */ |
| dumper->active = false; |
| } |
| rcu_read_unlock(); |
| } |
| |
| /** |
| * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
| * @dumper: registered kmsg dumper |
| * @syslog: include the "<4>" prefixes |
| * @line: buffer to copy the line to |
| * @size: maximum size of the buffer |
| * @len: length of line placed into buffer |
| * |
| * Start at the beginning of the kmsg buffer, with the oldest kmsg |
| * record, and copy one record into the provided buffer. |
| * |
| * Consecutive calls will return the next available record moving |
| * towards the end of the buffer with the youngest messages. |
| * |
| * A return value of FALSE indicates that there are no more records to |
| * read. |
| * |
| * The function is similar to kmsg_dump_get_line(), but grabs no locks. |
| */ |
| bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
| char *line, size_t size, size_t *len) |
| { |
| struct log *msg; |
| size_t l = 0; |
| bool ret = false; |
| |
| if (!dumper->active) |
| goto out; |
| |
| if (dumper->cur_seq < log_first_seq) { |
| /* messages are gone, move to first available one */ |
| dumper->cur_seq = log_first_seq; |
| dumper->cur_idx = log_first_idx; |
| } |
| |
| /* last entry */ |
| if (dumper->cur_seq >= log_next_seq) |
| goto out; |
| |
| msg = log_from_idx(dumper->cur_idx); |
| l = msg_print_text(msg, 0, syslog, line, size); |
| |
| dumper->cur_idx = log_next(dumper->cur_idx); |
| dumper->cur_seq++; |
| ret = true; |
| out: |
| if (len) |
| *len = l; |
| return ret; |
| } |
| |
| /** |
| * kmsg_dump_get_line - retrieve one kmsg log line |
| * @dumper: registered kmsg dumper |
| * @syslog: include the "<4>" prefixes |
| * @line: buffer to copy the line to |
| * @size: maximum size of the buffer |
| * @len: length of line placed into buffer |
| * |
| * Start at the beginning of the kmsg buffer, with the oldest kmsg |
| * record, and copy one record into the provided buffer. |
| * |
| * Consecutive calls will return the next available record moving |
| * towards the end of the buffer with the youngest messages. |
| * |
| * A return value of FALSE indicates that there are no more records to |
| * read. |
| */ |
| bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, |
| char *line, size_t size, size_t *len) |
| { |
| unsigned long flags; |
| bool ret; |
| |
| raw_spin_lock_irqsave(&logbuf_lock, flags); |
| ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); |
| raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
| |
| /** |
| * kmsg_dump_get_buffer - copy kmsg log lines |
| * @dumper: registered kmsg dumper |
| * @syslog: include the "<4>" prefixes |
| * @buf: buffer to copy the line to |
| * @size: maximum size of the buffer |
| * @len: length of line placed into buffer |
| * |
| * Start at the end of the kmsg buffer and fill the provided buffer |
| * with as many of the the *youngest* kmsg records that fit into it. |
| * If the buffer is large enough, all available kmsg records will be |
| * copied with a single call. |
| * |
| * Consecutive calls will fill the buffer with the next block of |
| * available older records, not including the earlier retrieved ones. |
| * |
| * A return value of FALSE indicates that there are no more records to |
| * read. |
| */ |
| bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, |
| char *buf, size_t size, size_t *len) |
| { |
| unsigned long flags; |
| u64 seq; |
| u32 idx; |
| u64 next_seq; |
| u32 next_idx; |
| enum log_flags prev; |
| size_t l = 0; |
| bool ret = false; |
| |
| if (!dumper->active) |
| goto out; |
| |
| raw_spin_lock_irqsave(&logbuf_lock, flags); |
| if (dumper->cur_seq < log_first_seq) { |
| /* messages are gone, move to first available one */ |
| dumper->cur_seq = log_first_seq; |
| dumper->cur_idx = log_first_idx; |
| } |
| |
| /* last entry */ |
| if (dumper->cur_seq >= dumper->next_seq) { |
| raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| goto out; |
| } |
| |
| /* calculate length of entire buffer */ |
| seq = dumper->cur_seq; |
| idx = dumper->cur_idx; |
| prev = 0; |
| while (seq < dumper->next_seq) { |
| struct log *msg = log_from_idx(idx); |
| |
| l += msg_print_text(msg, prev, true, NULL, 0); |
| idx = log_next(idx); |
| seq++; |
| prev = msg->flags; |
| } |
| |
| /* move first record forward until length fits into the buffer */ |
| seq = dumper->cur_seq; |
| idx = dumper->cur_idx; |
| prev = 0; |
| while (l > size && seq < dumper->next_seq) { |
| struct log *msg = log_from_idx(idx); |
| |
| l -= msg_print_text(msg, prev, true, NULL, 0); |
| idx = log_next(idx); |
| seq++; |
| prev = msg->flags; |
| } |
| |
| /* last message in next interation */ |
| next_seq = seq; |
| next_idx = idx; |
| |
| l = 0; |
| prev = 0; |
| while (seq < dumper->next_seq) { |
| struct log *msg = log_from_idx(idx); |
| |
| l += msg_print_text(msg, prev, syslog, buf + l, size - l); |
| idx = log_next(idx); |
| seq++; |
| prev = msg->flags; |
| } |
| |
| dumper->next_seq = next_seq; |
| dumper->next_idx = next_idx; |
| ret = true; |
| raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| out: |
| if (len) |
| *len = l; |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); |
| |
| /** |
| * kmsg_dump_rewind_nolock - reset the interator (unlocked version) |
| * @dumper: registered kmsg dumper |
| * |
| * Reset the dumper's iterator so that kmsg_dump_get_line() and |
| * kmsg_dump_get_buffer() can be called again and used multiple |
| * times within the same dumper.dump() callback. |
| * |
| * The function is similar to kmsg_dump_rewind(), but grabs no locks. |
| */ |
| void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) |
| { |
| dumper->cur_seq = clear_seq; |
| dumper->cur_idx = clear_idx; |
| dumper->next_seq = log_next_seq; |
| dumper->next_idx = log_next_idx; |
| } |
| |
| /** |
| * kmsg_dump_rewind - reset the interator |
| * @dumper: registered kmsg dumper |
| * |
| * Reset the dumper's iterator so that kmsg_dump_get_line() and |
| * kmsg_dump_get_buffer() can be called again and used multiple |
| * times within the same dumper.dump() callback. |
| */ |
| void kmsg_dump_rewind(struct kmsg_dumper *dumper) |
| { |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&logbuf_lock, flags); |
| kmsg_dump_rewind_nolock(dumper); |
| raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
| |
| static char dump_stack_arch_desc_str[128]; |
| |
| /** |
| * dump_stack_set_arch_desc - set arch-specific str to show with task dumps |
| * @fmt: printf-style format string |
| * @...: arguments for the format string |
| * |
| * The configured string will be printed right after utsname during task |
| * dumps. Usually used to add arch-specific system identifiers. If an |
| * arch wants to make use of such an ID string, it should initialize this |
| * as soon as possible during boot. |
| */ |
| void __init dump_stack_set_arch_desc(const char *fmt, ...) |
| { |
| va_list args; |
| |
| va_start(args, fmt); |
| vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), |
| fmt, args); |
| va_end(args); |
| } |
| |
| /** |
| * dump_stack_print_info - print generic debug info for dump_stack() |
| * @log_lvl: log level |
| * |
| * Arch-specific dump_stack() implementations can use this function to |
| * print out the same debug information as the generic dump_stack(). |
| */ |
| void dump_stack_print_info(const char *log_lvl) |
| { |
| printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", |
| log_lvl, raw_smp_processor_id(), current->pid, current->comm, |
| print_tainted(), init_utsname()->release, |
| (int)strcspn(init_utsname()->version, " "), |
| init_utsname()->version); |
| |
| if (dump_stack_arch_desc_str[0] != '\0') |
| printk("%sHardware name: %s\n", |
| log_lvl, dump_stack_arch_desc_str); |
| |
| print_worker_info(log_lvl, current); |
| } |
| |
| /** |
| * show_regs_print_info - print generic debug info for show_regs() |
| * @log_lvl: log level |
| * |
| * show_regs() implementations can use this function to print out generic |
| * debug information. |
| */ |
| void show_regs_print_info(const char *log_lvl) |
| { |
| dump_stack_print_info(log_lvl); |
| |
| printk("%stask: %p ti: %p task.ti: %p\n", |
| log_lvl, current, current_thread_info(), |
| task_thread_info(current)); |
| } |
| |
| #endif |