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