| // |
| // C++ Interface: diskio (Unix components [Linux, FreeBSD, Mac OS X]) |
| // |
| // Description: Class to handle low-level disk I/O for GPT fdisk |
| // |
| // |
| // Author: Rod Smith <rodsmith@rodsbooks.com>, (C) 2009 |
| // |
| // Copyright: See COPYING file that comes with this distribution |
| // |
| // |
| // This program is copyright (c) 2009 by Roderick W. Smith. It is distributed |
| // under the terms of the GNU GPL version 2, as detailed in the COPYING file. |
| |
| #define __STDC_LIMIT_MACROS |
| #ifndef __STDC_CONSTANT_MACROS |
| #define __STDC_CONSTANT_MACROS |
| #endif |
| |
| #include <sys/ioctl.h> |
| #include <string.h> |
| #include <string> |
| #include <stdint.h> |
| #include <unistd.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <sys/stat.h> |
| #include <unistd.h> |
| |
| #ifdef __linux__ |
| #include "linux/hdreg.h" |
| #endif |
| |
| #include <iostream> |
| |
| #include "diskio.h" |
| |
| using namespace std; |
| |
| // Returns the official "real" name for a shortened version of same. |
| // Trivial here; more important in Windows |
| void DiskIO::MakeRealName(void) { |
| realFilename = userFilename; |
| } // DiskIO::MakeRealName() |
| |
| // Open the currently on-record file for reading. Returns 1 if the file is |
| // already open or is opened by this call, 0 if opening the file doesn't |
| // work. |
| int DiskIO::OpenForRead(void) { |
| int shouldOpen = 1; |
| struct stat64 st; |
| |
| if (isOpen) { // file is already open |
| if (openForWrite) { |
| Close(); |
| } else { |
| shouldOpen = 0; |
| } // if/else |
| } // if |
| |
| if (shouldOpen) { |
| fd = open(realFilename.c_str(), O_RDONLY); |
| if (fd == -1) { |
| cerr << "Problem opening " << realFilename << " for reading! Error is " << errno << ".\n"; |
| if (errno == EACCES) // User is probably not running as root |
| cerr << "You must run this program as root or use sudo!\n"; |
| if (errno == ENOENT) |
| cerr << "The specified file does not exist!\n"; |
| realFilename = ""; |
| userFilename = ""; |
| isOpen = 0; |
| openForWrite = 0; |
| } else { |
| isOpen = 0; |
| openForWrite = 0; |
| if (fstat64(fd, &st) == 0) { |
| if (S_ISDIR(st.st_mode)) |
| cerr << "The specified path is a directory!\n"; |
| #if !(defined(__FreeBSD__) || defined(__FreeBSD_kernel__)) \ |
| && !defined(__APPLE__) |
| else if (S_ISCHR(st.st_mode)) |
| cerr << "The specified path is a character device!\n"; |
| #endif |
| else if (S_ISFIFO(st.st_mode)) |
| cerr << "The specified path is a FIFO!\n"; |
| else if (S_ISSOCK(st.st_mode)) |
| cerr << "The specified path is a socket!\n"; |
| else |
| isOpen = 1; |
| } // if (fstat64()...) |
| } // if/else |
| } // if |
| |
| return isOpen; |
| } // DiskIO::OpenForRead(void) |
| |
| // An extended file-open function. This includes some system-specific checks. |
| // Returns 1 if the file is open, 0 otherwise.... |
| int DiskIO::OpenForWrite(void) { |
| if ((isOpen) && (openForWrite)) |
| return 1; |
| |
| // Close the disk, in case it's already open for reading only.... |
| Close(); |
| |
| // try to open the device; may fail.... |
| fd = open(realFilename.c_str(), O_WRONLY | O_CREAT, S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH); |
| #ifdef __APPLE__ |
| // MacOS X requires a shared lock under some circumstances.... |
| if (fd < 0) { |
| cerr << "Warning: Devices opened with shared lock will not have their\npartition table automatically reloaded!\n"; |
| fd = open(realFilename.c_str(), O_WRONLY | O_SHLOCK); |
| } // if |
| #endif |
| if (fd >= 0) { |
| isOpen = 1; |
| openForWrite = 1; |
| } else { |
| isOpen = 0; |
| openForWrite = 0; |
| } // if/else |
| return isOpen; |
| } // DiskIO::OpenForWrite(void) |
| |
| // Close the disk device. Note that this does NOT erase the stored filenames, |
| // so the file can be re-opened without specifying the filename. |
| void DiskIO::Close(void) { |
| if (isOpen) |
| if (close(fd) < 0) |
| cerr << "Warning! Problem closing file!\n"; |
| isOpen = 0; |
| openForWrite = 0; |
| } // DiskIO::Close() |
| |
| // Returns block size of device pointed to by fd file descriptor. If the ioctl |
| // returns an error condition, print a warning but return a value of SECTOR_SIZE |
| // (512). If the disk can't be opened at all, return a value of 0. |
| int DiskIO::GetBlockSize(void) { |
| int err = -1, blockSize = 0; |
| #ifdef __sun__ |
| struct dk_minfo minfo; |
| #endif |
| |
| // If disk isn't open, try to open it.... |
| if (!isOpen) { |
| OpenForRead(); |
| } // if |
| |
| if (isOpen) { |
| #ifdef __APPLE__ |
| err = ioctl(fd, DKIOCGETBLOCKSIZE, &blockSize); |
| #endif |
| #ifdef __sun__ |
| err = ioctl(fd, DKIOCGMEDIAINFO, &minfo); |
| if (err == 0) |
| blockSize = minfo.dki_lbsize; |
| #endif |
| #if defined (__FreeBSD__) || defined (__FreeBSD_kernel__) |
| err = ioctl(fd, DIOCGSECTORSIZE, &blockSize); |
| #endif |
| #ifdef __linux__ |
| err = ioctl(fd, BLKSSZGET, &blockSize); |
| #endif |
| |
| if (err == -1) { |
| blockSize = SECTOR_SIZE; |
| // ENOTTY = inappropriate ioctl; probably being called on a disk image |
| // file, so don't display the warning message.... |
| // 32-bit code returns EINVAL, I don't know why. I know I'm treading on |
| // thin ice here, but it should be OK in all but very weird cases.... |
| if ((errno != ENOTTY) && (errno != EINVAL)) { |
| cerr << "\aError " << errno << " when determining sector size! Setting sector size to " |
| << SECTOR_SIZE << "\n"; |
| cout << "Disk device is " << realFilename << "\n"; |
| } // if |
| } // if (err == -1) |
| } // if (isOpen) |
| |
| return (blockSize); |
| } // DiskIO::GetBlockSize() |
| |
| // Returns the number of heads, according to the kernel, or 255 if the |
| // correct value can't be determined. |
| uint32_t DiskIO::GetNumHeads(void) { |
| uint32_t numHeads = 255; |
| |
| #ifdef HDIO_GETGEO |
| struct hd_geometry geometry; |
| |
| // If disk isn't open, try to open it.... |
| if (!isOpen) |
| OpenForRead(); |
| |
| if (!ioctl(fd, HDIO_GETGEO, &geometry)) |
| numHeads = (uint32_t) geometry.heads; |
| #endif |
| return numHeads; |
| } // DiskIO::GetNumHeads(); |
| |
| // Returns the number of sectors per track, according to the kernel, or 63 |
| // if the correct value can't be determined. |
| uint32_t DiskIO::GetNumSecsPerTrack(void) { |
| uint32_t numSecs = 63; |
| |
| #ifdef HDIO_GETGEO |
| struct hd_geometry geometry; |
| |
| // If disk isn't open, try to open it.... |
| if (!isOpen) |
| OpenForRead(); |
| |
| if (!ioctl(fd, HDIO_GETGEO, &geometry)) |
| numSecs = (uint32_t) geometry.sectors; |
| #endif |
| return numSecs; |
| } // DiskIO::GetNumSecsPerTrack() |
| |
| // Resync disk caches so the OS uses the new partition table. This code varies |
| // a lot from one OS to another. |
| // Returns 1 on success, 0 if the kernel continues to use the old partition table. |
| // (Note that for most OSes, the default of 0 is returned because I've not yet |
| // looked into how to test for success in the underlying system calls...) |
| int DiskIO::DiskSync(void) { |
| int i, retval = 0, platformFound = 0; |
| |
| // If disk isn't open, try to open it.... |
| if (!isOpen) { |
| OpenForRead(); |
| } // if |
| |
| if (isOpen) { |
| sync(); |
| #if defined(__APPLE__) || defined(__sun__) |
| cout << "Warning: The kernel may continue to use old or deleted partitions.\n" |
| << "You should reboot or remove the drive.\n"; |
| /* don't know if this helps |
| * it definitely will get things on disk though: |
| * http://topiks.org/mac-os-x/0321278542/ch12lev1sec8.html */ |
| #ifdef __sun__ |
| i = ioctl(fd, DKIOCFLUSHWRITECACHE); |
| #else |
| i = ioctl(fd, DKIOCSYNCHRONIZECACHE); |
| #endif |
| platformFound++; |
| #endif |
| #if defined (__FreeBSD__) || defined (__FreeBSD_kernel__) |
| sleep(2); |
| i = ioctl(fd, DIOCGFLUSH); |
| cout << "Warning: The kernel may continue to use old or deleted partitions.\n" |
| << "You should reboot or remove the drive.\n"; |
| platformFound++; |
| #endif |
| #ifdef __linux__ |
| sleep(1); // Theoretically unnecessary, but ioctl() fails sometimes if omitted.... |
| fsync(fd); |
| i = ioctl(fd, BLKRRPART); |
| if (i) { |
| cout << "Warning: The kernel is still using the old partition table.\n" |
| << "The new table will be used at the next reboot or after you\n" |
| << "run partprobe(8) or kpartx(8)\n"; |
| } else { |
| retval = 1; |
| } // if/else |
| platformFound++; |
| #endif |
| if (platformFound == 0) |
| cerr << "Warning: Platform not recognized!\n"; |
| if (platformFound > 1) |
| cerr << "\nWarning: We seem to be running on multiple platforms!\n"; |
| } // if (isOpen) |
| return retval; |
| } // DiskIO::DiskSync() |
| |
| // Seek to the specified sector. Returns 1 on success, 0 on failure. |
| // Note that seeking beyond the end of the file is NOT detected as a failure! |
| int DiskIO::Seek(uint64_t sector) { |
| int retval = 1; |
| off_t seekTo, sought; |
| |
| // If disk isn't open, try to open it.... |
| if (!isOpen) { |
| retval = OpenForRead(); |
| } // if |
| |
| if (isOpen) { |
| seekTo = sector * (uint64_t) GetBlockSize(); |
| sought = lseek64(fd, seekTo, SEEK_SET); |
| if (sought != seekTo) { |
| retval = 0; |
| } // if |
| } // if |
| return retval; |
| } // DiskIO::Seek() |
| |
| // A variant on the standard read() function. Done to work around |
| // limitations in FreeBSD concerning the matching of the sector |
| // size with the number of bytes read. |
| // Returns the number of bytes read into buffer. |
| int DiskIO::Read(void* buffer, int numBytes) { |
| int blockSize, numBlocks, retval = 0; |
| char* tempSpace; |
| |
| // If disk isn't open, try to open it.... |
| if (!isOpen) { |
| OpenForRead(); |
| } // if |
| |
| if (isOpen) { |
| // Compute required space and allocate memory |
| blockSize = GetBlockSize(); |
| if (numBytes <= blockSize) { |
| numBlocks = 1; |
| tempSpace = new char [blockSize]; |
| } else { |
| numBlocks = numBytes / blockSize; |
| if ((numBytes % blockSize) != 0) |
| numBlocks++; |
| tempSpace = new char [numBlocks * blockSize]; |
| } // if/else |
| if (tempSpace == NULL) { |
| cerr << "Unable to allocate memory in DiskIO::Read()! Terminating!\n"; |
| exit(1); |
| } // if |
| |
| // Read the data into temporary space, then copy it to buffer |
| retval = read(fd, tempSpace, numBlocks * blockSize); |
| memcpy(buffer, tempSpace, numBytes); |
| |
| // Adjust the return value, if necessary.... |
| if (((numBlocks * blockSize) != numBytes) && (retval > 0)) |
| retval = numBytes; |
| |
| delete[] tempSpace; |
| } // if (isOpen) |
| return retval; |
| } // DiskIO::Read() |
| |
| // A variant on the standard write() function. Done to work around |
| // limitations in FreeBSD concerning the matching of the sector |
| // size with the number of bytes read. |
| // Returns the number of bytes written. |
| int DiskIO::Write(void* buffer, int numBytes) { |
| int blockSize = 512, i, numBlocks, retval = 0; |
| char* tempSpace; |
| |
| // If disk isn't open, try to open it.... |
| if ((!isOpen) || (!openForWrite)) { |
| OpenForWrite(); |
| } // if |
| |
| if (isOpen) { |
| // Compute required space and allocate memory |
| blockSize = GetBlockSize(); |
| if (numBytes <= blockSize) { |
| numBlocks = 1; |
| tempSpace = new char [blockSize]; |
| } else { |
| numBlocks = numBytes / blockSize; |
| if ((numBytes % blockSize) != 0) numBlocks++; |
| tempSpace = new char [numBlocks * blockSize]; |
| } // if/else |
| if (tempSpace == NULL) { |
| cerr << "Unable to allocate memory in DiskIO::Write()! Terminating!\n"; |
| exit(1); |
| } // if |
| |
| // Copy the data to my own buffer, then write it |
| memcpy(tempSpace, buffer, numBytes); |
| for (i = numBytes; i < numBlocks * blockSize; i++) { |
| tempSpace[i] = 0; |
| } // for |
| retval = write(fd, tempSpace, numBlocks * blockSize); |
| |
| // Adjust the return value, if necessary.... |
| if (((numBlocks * blockSize) != numBytes) && (retval > 0)) |
| retval = numBytes; |
| |
| delete[] tempSpace; |
| } // if (isOpen) |
| return retval; |
| } // DiskIO:Write() |
| |
| /************************************************************************************** |
| * * |
| * Below functions are lifted from various sources, as documented in comments before * |
| * each one. * |
| * * |
| **************************************************************************************/ |
| |
| // The disksize function is taken from the Linux fdisk code and modified |
| // greatly since then to enable FreeBSD and MacOS support, as well as to |
| // return correct values for disk image files. |
| uint64_t DiskIO::DiskSize(int *err) { |
| uint64_t sectors = 0; // size in sectors |
| off_t bytes = 0; // size in bytes |
| struct stat64 st; |
| int platformFound = 0; |
| #ifdef __sun__ |
| struct dk_minfo minfo; |
| #endif |
| |
| // If disk isn't open, try to open it.... |
| if (!isOpen) { |
| OpenForRead(); |
| } // if |
| |
| if (isOpen) { |
| // Note to self: I recall testing a simplified version of |
| // this code, similar to what's in the __APPLE__ block, |
| // on Linux, but I had some problems. IIRC, it ran OK on 32-bit |
| // systems but not on 64-bit. Keep this in mind in case of |
| // 32/64-bit issues on MacOS.... |
| #ifdef __APPLE__ |
| *err = ioctl(fd, DKIOCGETBLOCKCOUNT, §ors); |
| platformFound++; |
| #endif |
| #ifdef __sun__ |
| *err = ioctl(fd, DKIOCGMEDIAINFO, &minfo); |
| if (*err == 0) |
| sectors = minfo.dki_capacity; |
| platformFound++; |
| #endif |
| #if defined (__FreeBSD__) || defined (__FreeBSD_kernel__) |
| *err = ioctl(fd, DIOCGMEDIASIZE, &bytes); |
| long long b = GetBlockSize(); |
| sectors = bytes / b; |
| platformFound++; |
| #endif |
| #ifdef __linux__ |
| long sz; |
| long long b; |
| *err = ioctl(fd, BLKGETSIZE, &sz); |
| if (*err) { |
| sectors = sz = 0; |
| } // if |
| if ((!*err) || (errno == EFBIG)) { |
| *err = ioctl(fd, BLKGETSIZE64, &b); |
| if (*err || b == 0 || b == sz) |
| sectors = sz; |
| else |
| sectors = (b >> 9); |
| } // if |
| // Unintuitively, the above returns values in 512-byte blocks, no |
| // matter what the underlying device's block size. Correct for this.... |
| sectors /= (GetBlockSize() / 512); |
| platformFound++; |
| #endif |
| if (platformFound != 1) |
| cerr << "Warning! We seem to be running on no known platform!\n"; |
| |
| // The above methods have failed, so let's assume it's a regular |
| // file (a QEMU image, dd backup, or what have you) and see what |
| // fstat() gives us.... |
| if ((sectors == 0) || (*err == -1)) { |
| if (fstat64(fd, &st) == 0) { |
| bytes = st.st_size; |
| if ((bytes % UINT64_C(512)) != 0) |
| cerr << "Warning: File size is not a multiple of 512 bytes!" |
| << " Misbehavior is likely!\n\a"; |
| sectors = bytes / UINT64_C(512); |
| } // if |
| } // if |
| } // if (isOpen) |
| return sectors; |
| } // DiskIO::DiskSize() |
