b5ceb1a9de
setuid() sets the effective user ID of the calling process. If the effective UID of the caller is root, the real UID and saved set-user-ID are also set. On success, zero is returned. On error, -1 is returned, and errno is set appropriately. there are cases where setuid() can fail even when the caller is UID 0; it is a grave security error to omit checking for a failure return from setuid(). if an environment limits the number of processes a user can have, setuid() might fail if the target uid already is at the limit. Fix is to check return value of setuid. Change-Id: I7aa5ab5e347603c69dc93188417cc4f4c81ffc75 BUG: 1221490 Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com> Reviewed-on: http://review.gluster.org/10780 Reviewed-by: Prasanna Kumar Kalever Tested-by: Prasanna Kumar Kalever Reviewed-by: Niels de Vos <ndevos@redhat.com> Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Gaurav Kumar Garg <ggarg@redhat.com>
283 lines
9.0 KiB
C
283 lines
9.0 KiB
C
/*
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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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Copyright (c) 2010 Gluster, Inc. <http://www.gluster.com>
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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-gluster-compat.h"
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/*
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* These functions (and gf_fuse_umount() in mount.c)
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* were originally taken from libfuse as of commit 7960e99e
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* (http://fuse.git.sourceforge.net/git/gitweb.cgi?p=fuse/fuse;a=commit;h=7960e99e)
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* almost verbatim. What has been changed upon adoption:
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* - style adopted to that of glusterfs
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* - s/fprintf/gf_log/
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* - s/free/FREE/, s/malloc/MALLOC/
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* - there are some other minor things
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*
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* For changes that were made later and syncs with upstream,
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* see the commit log and per-function comments.
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*/
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#ifdef GF_LINUX_HOST_OS
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/* FUSE: cherry-picked bd99f9cf */
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static int
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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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#else /* GF_LINUX_HOST_OS */
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#define mtab_needs_update(x) 1
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#endif /* GF_LINUX_HOST_OS */
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/* FUSE: called add_mount_legacy(); R.I.P. as of cbd3a2a8 */
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int
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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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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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if (!mtab_needs_update (mnt))
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return 0;
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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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GFFUSE_LOGERR ("%s: sigprocmask: %s",
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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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GFFUSE_LOGERR ("%s: fork: %s", 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 templ[] = "/tmp/fusermountXXXXXX";
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char *tmp;
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sigprocmask (SIG_SETMASK, &oldmask, NULL);
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res = setuid (geteuid ());
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if (res != 0) {
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GFFUSE_LOGERR ("%s: setuid: %s", progname, strerror (errno));
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exit (1);
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}
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/*
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* hide in a directory, where mount isn't able to resolve
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* fsname as a valid path
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*/
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tmp = mkdtemp (templ);
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if (!tmp) {
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GFFUSE_LOGERR ("%s: failed to create temporary directory",
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progname);
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exit (1);
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}
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if (chdir (tmp)) {
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GFFUSE_LOGERR ("%s: failed to chdir to %s: %s",
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progname, tmp, strerror (errno));
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exit (1);
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}
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rmdir (tmp);
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execl (_PATH_MOUNT, _PATH_MOUNT, "-i", "-f", "-t", type,
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"-o", opts, fsname, mnt, NULL);
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GFFUSE_LOGERR ("%s: failed to execute %s: %s",
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progname, _PATH_MOUNT, 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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GFFUSE_LOGERR ("%s: waitpid: %s", progname, strerror (errno));
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res = (res != -1 && status == 0) ? 0 : -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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char *
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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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GFFUSE_LOGERR ("%s: invalid mountpoint '%s'", progname, 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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GFFUSE_LOGERR ("%s: failed to allocate memory", 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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GFFUSE_LOGERR ("%s: bad mount point %s: %s", 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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GFFUSE_LOGERR ("%s: failed to allocate memory", progname);
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return dst;
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}
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/* FUSE: to support some changes that were reverted since
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* then, it was split in two (fuse_mnt_umount() and
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* exec_umount()); however the actual code is same as here
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* since 0197ce40
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*/
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int
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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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int status;
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sigset_t blockmask;
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sigset_t oldmask;
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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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GFFUSE_LOGERR ("%s: failed to unmount %s: %s",
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progname, abs_mnt, strerror (errno));
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return res;
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}
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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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GFFUSE_LOGERR ("%s: sigprocmask: %s", progname,
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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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GFFUSE_LOGERR ("%s: fork: %s", 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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sigprocmask (SIG_SETMASK, &oldmask, NULL);
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res = setuid (geteuid ());
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if (res != 0) {
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GFFUSE_LOGERR ("%s: setuid: %s", progname, strerror (errno));
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exit (1);
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}
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#ifdef GF_LINUX_HOST_OS
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execl ("/bin/umount", "/bin/umount", "-i", rel_mnt,
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lazy ? "-l" : NULL, NULL);
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GFFUSE_LOGERR ("%s: failed to execute /bin/umount: %s",
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progname, strerror (errno));
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#elif __NetBSD__
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/* exitting the filesystem causes the umount */
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exit (0);
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#else
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execl ("/sbin/umount", "/sbin/umount", "-f", rel_mnt, NULL);
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GFFUSE_LOGERR ("%s: failed to execute /sbin/umount: %s",
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progname, strerror (errno));
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#endif /* GF_LINUX_HOST_OS */
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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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GFFUSE_LOGERR ("%s: waitpid: %s", 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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