| /* |
| FUSE: Filesystem in Userspace |
| Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu> |
| |
| Architecture-independent mounting code. |
| |
| This program can be distributed under the terms of the GNU LGPLv2. |
| See the file COPYING.LIB. |
| */ |
| |
| #include "config.h" |
| #include "mount_util.h" |
| #include <stdio.h> |
| #include <unistd.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <signal.h> |
| #include <dirent.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <limits.h> |
| #include <paths.h> |
| #ifndef __NetBSD__ |
| #include <mntent.h> |
| #endif |
| #include <sys/stat.h> |
| #include <sys/wait.h> |
| #include <sys/mount.h> |
| #include <sys/param.h> |
| |
| #ifdef __NetBSD__ |
| #define umount2(mnt, flags) unmount(mnt, (flags == 2) ? MNT_FORCE : 0) |
| #define mtab_needs_update(mnt) 0 |
| #else |
| static int mtab_needs_update(const char *mnt) |
| { |
| int res; |
| struct stat stbuf; |
| |
| /* If mtab is within new mount, don't touch it */ |
| if (strncmp(mnt, _PATH_MOUNTED, strlen(mnt)) == 0 && |
| _PATH_MOUNTED[strlen(mnt)] == '/') |
| return 0; |
| |
| /* |
| * Skip mtab update if /etc/mtab: |
| * |
| * - doesn't exist, |
| * - is a symlink, |
| * - is on a read-only filesystem. |
| */ |
| res = lstat(_PATH_MOUNTED, &stbuf); |
| if (res == -1) { |
| if (errno == ENOENT) |
| return 0; |
| } else { |
| uid_t ruid; |
| int err; |
| |
| if (S_ISLNK(stbuf.st_mode)) |
| return 0; |
| |
| ruid = getuid(); |
| if (ruid != 0) |
| setreuid(0, -1); |
| |
| res = access(_PATH_MOUNTED, W_OK); |
| err = (res == -1) ? errno : 0; |
| if (ruid != 0) |
| setreuid(ruid, -1); |
| |
| if (err == EROFS) |
| return 0; |
| } |
| |
| return 1; |
| } |
| #endif /* __NetBSD__ */ |
| |
| static int add_mount(const char *progname, const char *fsname, |
| const char *mnt, const char *type, const char *opts) |
| { |
| int res; |
| int status; |
| sigset_t blockmask; |
| sigset_t oldmask; |
| |
| sigemptyset(&blockmask); |
| sigaddset(&blockmask, SIGCHLD); |
| res = sigprocmask(SIG_BLOCK, &blockmask, &oldmask); |
| if (res == -1) { |
| fprintf(stderr, "%s: sigprocmask: %s\n", progname, strerror(errno)); |
| return -1; |
| } |
| |
| res = fork(); |
| if (res == -1) { |
| fprintf(stderr, "%s: fork: %s\n", progname, strerror(errno)); |
| goto out_restore; |
| } |
| if (res == 0) { |
| char *env = NULL; |
| |
| sigprocmask(SIG_SETMASK, &oldmask, NULL); |
| |
| if(setuid(geteuid()) == -1) { |
| fprintf(stderr, "%s: setuid: %s\n", progname, strerror(errno)); |
| res = -1; |
| goto out_restore; |
| } |
| |
| execle("/bin/mount", "/bin/mount", "--no-canonicalize", "-i", |
| "-f", "-t", type, "-o", opts, fsname, mnt, NULL, &env); |
| fprintf(stderr, "%s: failed to execute /bin/mount: %s\n", |
| progname, strerror(errno)); |
| exit(1); |
| } |
| res = waitpid(res, &status, 0); |
| if (res == -1) |
| fprintf(stderr, "%s: waitpid: %s\n", progname, strerror(errno)); |
| |
| if (status != 0) |
| res = -1; |
| |
| out_restore: |
| sigprocmask(SIG_SETMASK, &oldmask, NULL); |
| |
| return res; |
| } |
| |
| int fuse_mnt_add_mount(const char *progname, const char *fsname, |
| const char *mnt, const char *type, const char *opts) |
| { |
| if (!mtab_needs_update(mnt)) |
| return 0; |
| |
| return add_mount(progname, fsname, mnt, type, opts); |
| } |
| |
| static int exec_umount(const char *progname, const char *rel_mnt, int lazy) |
| { |
| int res; |
| int status; |
| sigset_t blockmask; |
| sigset_t oldmask; |
| |
| sigemptyset(&blockmask); |
| sigaddset(&blockmask, SIGCHLD); |
| res = sigprocmask(SIG_BLOCK, &blockmask, &oldmask); |
| if (res == -1) { |
| fprintf(stderr, "%s: sigprocmask: %s\n", progname, strerror(errno)); |
| return -1; |
| } |
| |
| res = fork(); |
| if (res == -1) { |
| fprintf(stderr, "%s: fork: %s\n", progname, strerror(errno)); |
| goto out_restore; |
| } |
| if (res == 0) { |
| char *env = NULL; |
| |
| sigprocmask(SIG_SETMASK, &oldmask, NULL); |
| |
| if(setuid(geteuid()) == -1) { |
| fprintf(stderr, "%s: setuid: %s\n", progname, strerror(errno)); |
| res = -1; |
| goto out_restore; |
| } |
| |
| if (lazy) { |
| execle("/bin/umount", "/bin/umount", "-i", rel_mnt, |
| "-l", NULL, &env); |
| } else { |
| execle("/bin/umount", "/bin/umount", "-i", rel_mnt, |
| NULL, &env); |
| } |
| fprintf(stderr, "%s: failed to execute /bin/umount: %s\n", |
| progname, strerror(errno)); |
| exit(1); |
| } |
| res = waitpid(res, &status, 0); |
| if (res == -1) |
| fprintf(stderr, "%s: waitpid: %s\n", progname, strerror(errno)); |
| |
| if (status != 0) { |
| res = -1; |
| } |
| |
| out_restore: |
| sigprocmask(SIG_SETMASK, &oldmask, NULL); |
| return res; |
| |
| } |
| |
| int fuse_mnt_umount(const char *progname, const char *abs_mnt, |
| const char *rel_mnt, int lazy) |
| { |
| int res; |
| |
| if (!mtab_needs_update(abs_mnt)) { |
| res = umount2(rel_mnt, lazy ? 2 : 0); |
| if (res == -1) |
| fprintf(stderr, "%s: failed to unmount %s: %s\n", |
| progname, abs_mnt, strerror(errno)); |
| return res; |
| } |
| |
| return exec_umount(progname, rel_mnt, lazy); |
| } |
| |
| static int remove_mount(const char *progname, const char *mnt) |
| { |
| int res; |
| int status; |
| sigset_t blockmask; |
| sigset_t oldmask; |
| |
| sigemptyset(&blockmask); |
| sigaddset(&blockmask, SIGCHLD); |
| res = sigprocmask(SIG_BLOCK, &blockmask, &oldmask); |
| if (res == -1) { |
| fprintf(stderr, "%s: sigprocmask: %s\n", progname, strerror(errno)); |
| return -1; |
| } |
| |
| res = fork(); |
| if (res == -1) { |
| fprintf(stderr, "%s: fork: %s\n", progname, strerror(errno)); |
| goto out_restore; |
| } |
| if (res == 0) { |
| char *env = NULL; |
| |
| sigprocmask(SIG_SETMASK, &oldmask, NULL); |
| |
| if(setuid(geteuid()) == -1) { |
| fprintf(stderr, "%s: setuid: %s\n", progname, strerror(errno)); |
| res = -1; |
| goto out_restore; |
| } |
| |
| execle("/bin/umount", "/bin/umount", "--no-canonicalize", "-i", |
| "--fake", mnt, NULL, &env); |
| fprintf(stderr, "%s: failed to execute /bin/umount: %s\n", |
| progname, strerror(errno)); |
| exit(1); |
| } |
| res = waitpid(res, &status, 0); |
| if (res == -1) |
| fprintf(stderr, "%s: waitpid: %s\n", progname, strerror(errno)); |
| |
| if (status != 0) |
| res = -1; |
| |
| out_restore: |
| sigprocmask(SIG_SETMASK, &oldmask, NULL); |
| return res; |
| } |
| |
| int fuse_mnt_remove_mount(const char *progname, const char *mnt) |
| { |
| if (!mtab_needs_update(mnt)) |
| return 0; |
| |
| return remove_mount(progname, mnt); |
| } |
| |
| char *fuse_mnt_resolve_path(const char *progname, const char *orig) |
| { |
| char buf[PATH_MAX]; |
| char *copy; |
| char *dst; |
| char *end; |
| char *lastcomp; |
| const char *toresolv; |
| |
| if (!orig[0]) { |
| fprintf(stderr, "%s: invalid mountpoint '%s'\n", progname, |
| orig); |
| return NULL; |
| } |
| |
| copy = strdup(orig); |
| if (copy == NULL) { |
| fprintf(stderr, "%s: failed to allocate memory\n", progname); |
| return NULL; |
| } |
| |
| toresolv = copy; |
| lastcomp = NULL; |
| for (end = copy + strlen(copy) - 1; end > copy && *end == '/'; end --); |
| if (end[0] != '/') { |
| char *tmp; |
| end[1] = '\0'; |
| tmp = strrchr(copy, '/'); |
| if (tmp == NULL) { |
| lastcomp = copy; |
| toresolv = "."; |
| } else { |
| lastcomp = tmp + 1; |
| if (tmp == copy) |
| toresolv = "/"; |
| } |
| if (strcmp(lastcomp, ".") == 0 || strcmp(lastcomp, "..") == 0) { |
| lastcomp = NULL; |
| toresolv = copy; |
| } |
| else if (tmp) |
| tmp[0] = '\0'; |
| } |
| if (realpath(toresolv, buf) == NULL) { |
| fprintf(stderr, "%s: bad mount point %s: %s\n", progname, orig, |
| strerror(errno)); |
| free(copy); |
| return NULL; |
| } |
| if (lastcomp == NULL) |
| dst = strdup(buf); |
| else { |
| dst = (char *) malloc(strlen(buf) + 1 + strlen(lastcomp) + 1); |
| if (dst) { |
| unsigned buflen = strlen(buf); |
| if (buflen && buf[buflen-1] == '/') |
| sprintf(dst, "%s%s", buf, lastcomp); |
| else |
| sprintf(dst, "%s/%s", buf, lastcomp); |
| } |
| } |
| free(copy); |
| if (dst == NULL) |
| fprintf(stderr, "%s: failed to allocate memory\n", progname); |
| return dst; |
| } |
| |
| int fuse_mnt_check_fuseblk(void) |
| { |
| char buf[256]; |
| FILE *f = fopen("/proc/filesystems", "r"); |
| if (!f) |
| return 1; |
| |
| while (fgets(buf, sizeof(buf), f)) |
| if (strstr(buf, "fuseblk\n")) { |
| fclose(f); |
| return 1; |
| } |
| |
| fclose(f); |
| return 0; |
| } |