*/
/* This program does the mounting and unmounting of FUSE filesystems */
-/*
- * NOTE: This program should be part of (or be called from) /bin/mount
- *
- * Unless that is done, operations on /etc/mtab are not under lock, and so
- * data in this file may be lost. (I will _not_ reimplement that locking,
- * and anyway that should be done in libc, if possible. But probably it
- * isn't).
- */
-
#include <config.h>
#include <stdio.h>
#include <pwd.h>
#include <mntent.h>
#include <dirent.h>
-#include <sys/param.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/fsuid.h>
#include <sys/socket.h>
-#include <sys/un.h>
#include <sys/utsname.h>
-#include <sys/sysmacros.h>
-
-#ifdef HAVE_SELINUX_SELINUX_H
-#include <selinux/selinux.h>
-#endif
#define FUSE_COMMFD_ENV "_FUSE_COMMFD"
static int do_unmount(const char *mnt, int quiet, int lazy)
{
- int res = umount2(mnt, lazy ? 2 : 0);
- if (res == -1) {
- if (!quiet)
- fprintf(stderr, "%s: failed to unmount %s: %s\n",
- progname, mnt, strerror(errno));
- }
- return res;
-}
-
-#ifndef IGNORE_MTAB
-/* use a lock file so that multiple fusermount processes don't try and
- modify the mtab file at once! */
-static int lock_mtab(void)
-{
- const char *mtab_lock = _PATH_MOUNTED ".fuselock";
- int mtablock;
int res;
- struct stat mtab_stat;
+ int status;
- /* /etc/mtab could be a symlink to /proc/mounts */
- if (!lstat(_PATH_MOUNTED, &mtab_stat)) {
- if (S_ISLNK(mtab_stat.st_mode))
- return -1;
+ (void) quiet;
+ res = fork();
+ if (res == -1) {
+ perror("fork");
+ return -1;
}
-
- mtablock = open(mtab_lock, O_RDWR | O_CREAT, 0600);
- if (mtablock >= 0) {
- res = lockf(mtablock, F_LOCK, 0);
- if (res < 0)
- fprintf(stderr, "%s: error getting lock", progname);
- } else
- fprintf(stderr, "%s: unable to open fuse lock file\n", progname);
-
- return mtablock;
-}
-
-static void unlock_mtab(int mtablock)
-{
- if (mtablock >= 0) {
- lockf(mtablock, F_ULOCK, 0);
- close(mtablock);
+ if (res == 0) {
+ setuid(geteuid());
+ execl("/bin/umount", "/bin/umount", "-i", mnt, lazy ? "-l" : NULL,
+ NULL);
+ perror("execl /bin/umount");
+ exit(1);
}
-}
-
-/* Glibc addmntent() doesn't encode '\n', misencodes '\t' as '\n'
- (version 2.3.2), and encodes '\\' differently as mount(8). So
- let's not allow those characters, they are not all that usual in
- filenames. */
-static int check_name(const char *name)
-{
- const char *s;
- for (s = "\n\t\\"; *s; s++) {
- if (strchr(name, *s)) {
- fprintf(stderr, "%s: illegal character 0x%02x in mount entry\n",
- progname, *s);
- return -1;
- }
+ res = waitpid(res, &status, 0);
+ if (res == -1) {
+ perror("waitpid");
+ return -1;
}
+ if (status != 0)
+ return -1;
+
return 0;
}
+#ifndef IGNORE_MTAB
static int add_mount(const char *fsname, const char *mnt, const char *type,
const char *opts)
{
int res;
- const char *mtab = _PATH_MOUNTED;
- struct mntent ent;
- FILE *fp;
+ int status;
- if (check_name(fsname) == -1 || check_name(mnt) == -1 ||
- check_name(type) == -1 || check_name(opts) == -1)
- return -1;
-
- fp = setmntent(mtab, "a");
- if (fp == NULL) {
- fprintf(stderr, "%s: failed to open %s: %s\n", progname, mtab,
- strerror(errno));
- return -1;
- }
-
- ent.mnt_fsname = (char *) fsname;
- ent.mnt_dir = (char *) mnt;
- ent.mnt_type = (char *) type;
- ent.mnt_opts = (char *) opts;
- ent.mnt_freq = 0;
- ent.mnt_passno = 0;
- res = addmntent(fp, &ent);
- if (res != 0) {
- fprintf(stderr, "%s: failed to add entry to %s: %s\n", progname,
- mtab, strerror(errno));
+ res = fork();
+ if (res == -1) {
+ perror("fork");
return -1;
}
-
- endmntent(fp);
- return 0;
-}
-
-static int unmount_rename(const char *mtab, const char *mtab_new)
-{
- int res;
- struct stat sbuf;
-
- if (stat(mtab, &sbuf) == 0)
- chown(mtab_new, sbuf.st_uid, sbuf.st_gid);
-
-#ifdef HAVE_LIBSELINUX
- {
- security_context_t filecon;
-
- if (getfilecon(mtab, &filecon) > 0) {
- setfilecon(mtab_new, filecon);
- if (filecon != NULL)
- freecon(filecon);
- }
+ if (res == 0) {
+ setuid(geteuid());
+ execl("/bin/mount", "/bin/mount", "-i", "-f", "-t", type, "-o", opts,
+ fsname, mnt, NULL);
+ perror("execl /bin/mount");
+ exit(1);
}
-#endif
-
- res = rename(mtab_new, mtab);
+ res = waitpid(res, &status, 0);
if (res == -1) {
- fprintf(stderr, "%s: failed to rename %s to %s: %s\n", progname,
- mtab_new, mtab, strerror(errno));
+ perror("waitpid");
return -1;
}
+ if (status != 0)
+ return -1;
+
return 0;
}
static int unmount_fuse(const char *mnt, int quiet, int lazy)
{
- int res;
- struct mntent *entp;
- FILE *fp;
- FILE *newfp = NULL;
- const char *user = NULL;
- char uidstr[32];
- unsigned uidlen = 0;
- int found;
- int issymlink = 0;
- struct stat stbuf;
- const char *mtab = _PATH_MOUNTED;
- const char *mtab_new = _PATH_MOUNTED "~fuse~";
-
- if (lstat(mtab, &stbuf) != -1 && S_ISLNK(stbuf.st_mode))
- issymlink = 1;
+ if (getuid() != 0) {
+ struct mntent *entp;
+ FILE *fp;
+ const char *user = NULL;
+ char uidstr[32];
+ unsigned uidlen = 0;
+ int found;
+ const char *mtab = _PATH_MOUNTED;
- fp = setmntent(mtab, "r");
- if (fp == NULL) {
- fprintf(stderr, "%s: failed to open %s: %s\n", progname, mtab,
- strerror(errno));
- return -1;
- }
+ user = get_user_name();
+ if (user == NULL)
+ return -1;
- if (!issymlink) {
- newfp = setmntent(mtab_new, "w");
- if (newfp == NULL) {
- fprintf(stderr, "%s: failed to open %s: %s\n", progname, mtab_new,
+ fp = setmntent(mtab, "r");
+ if (fp == NULL) {
+ fprintf(stderr, "%s: failed to open %s: %s\n", progname, mtab,
strerror(errno));
- endmntent(fp);
return -1;
}
- }
-
- if (getuid() != 0) {
- user = get_user_name();
- if (user == NULL)
- goto err_endmntent;
uidlen = sprintf(uidstr, "%u", getuid());
- }
- found = 0;
- while ((entp = getmntent(fp)) != NULL) {
- int removed = 0;
- if (!found && strcmp(entp->mnt_dir, mnt) == 0 &&
- (strcmp(entp->mnt_type, "fuse") == 0 ||
- strcmp(entp->mnt_type, "fuseblk") == 0)) {
- if (user == NULL)
- removed = 1;
- else {
+ found = 0;
+ while ((entp = getmntent(fp)) != NULL) {
+ if (!found && strcmp(entp->mnt_dir, mnt) == 0 &&
+ (strcmp(entp->mnt_type, "fuse") == 0 ||
+ strcmp(entp->mnt_type, "fuseblk") == 0)) {
char *p = strstr(entp->mnt_opts, "user=");
if (p && (p == entp->mnt_opts || *(p-1) == ',') &&
- strcmp(p + 5, user) == 0)
- removed = 1;
+ strcmp(p + 5, user) == 0) {
+ found = 1;
+ break;
+ }
/* /etc/mtab is a link pointing to /proc/mounts: */
else if ((p = strstr(entp->mnt_opts, "user_id=")) &&
(p == entp->mnt_opts || *(p-1) == ',') &&
strncmp(p + 8, uidstr, uidlen) == 0 &&
- (*(p+8+uidlen) == ',' || *(p+8+uidlen) == '\0'))
- removed = 1;
- }
- }
- if (removed)
- found = 1;
- else if (!issymlink) {
- res = addmntent(newfp, entp);
- if (res != 0) {
- fprintf(stderr, "%s: failed to add entry to %s: %s\n",
- progname, mtab_new, strerror(errno));
+ (*(p+8+uidlen) == ',' || *(p+8+uidlen) == '\0')) {
+ found = 1;
+ break;
+ }
}
}
- }
-
- endmntent(fp);
- if (!issymlink)
- endmntent(newfp);
+ endmntent(fp);
- if (!found) {
- if (!quiet)
- fprintf(stderr, "%s: entry for %s not found in %s\n", progname,
- mnt, mtab);
- goto err;
- }
-
- drop_privs();
- res = do_unmount(mnt, quiet, lazy);
- restore_privs();
- if (res == -1)
- goto err;
-
- if (!issymlink) {
- res = unmount_rename(mtab, mtab_new);
- if (res == -1)
- goto err;
+ if (!found) {
+ if (!quiet)
+ fprintf(stderr, "%s: entry for %s not found in %s\n", progname,
+ mnt, mtab);
+ return -1;
+ }
}
- return 0;
- err_endmntent:
- if (!issymlink)
- endmntent(newfp);
- endmntent(fp);
- err:
- if (!issymlink)
- unlink(mtab_new);
- return -1;
+ return do_unmount(mnt, quiet, lazy);
}
static int count_fuse_fs(void)
#else /* IGNORE_MTAB */
-static int lock_mtab()
-{
- return 0;
-}
-
-static void unlock_mtab(int mtablock)
-{
- (void) mtablock;
-}
-
static int count_fuse_fs()
{
return 0;
const char *real_mnt = mnt;
int currdir_fd = -1;
int mountpoint_fd = -1;
- int mtablock = -1;
fd = open_fuse_device(&dev);
if (fd == -1)
return -1;
- if (geteuid() == 0)
- mtablock = lock_mtab();
-
drop_privs();
read_conf();
if (mount_count >= mount_max) {
fprintf(stderr, "%s: too many FUSE filesystems mounted; mount_max=N can be set in /etc/fuse.conf\n", progname);
close(fd);
- unlock_mtab(mtablock);
return -1;
}
}
if (res == -1) {
close(fd);
- unlock_mtab(mtablock);
return -1;
}
if (geteuid() == 0) {
res = add_mount(fsname, mnt, type, mnt_opts);
- unlock_mtab(mtablock);
if (res == -1) {
umount2(mnt, 2); /* lazy umount */
close(fd);
umask(033);
if (unmount) {
- if (geteuid() == 0) {
- int mtablock = lock_mtab();
+ if (geteuid() == 0)
res = unmount_fuse(mnt, quiet, lazy);
- unlock_mtab(mtablock);
- } else
- res = do_unmount(mnt, quiet, lazy);
+ else {
+ res = umount2(mnt, lazy ? 2 : 0);
+ if (res == -1 && !quiet)
+ fprintf(stderr, "%s: failed to unmount %s: %s\n", progname,
+ mnt, strerror(errno));
+ }
if (res == -1)
exit(1);
return 0;
projects / qemu-gpiodev / libfuse.git / commitdiff