During a remount of a cifs filesystem, the mtab file is not properly updated, which
leads to a doubled entry of the same filesystem in the /etc/mtab file. This patch
adds a new function del_mtab() which is called before the add_mtab() in case the fs
is being remounted.
The del_mtab() function will delete from the mtab, the old entry from the filesystem which
is being remounted, and then, calls add_mtab() to add an updated entry to the mtab file.
Signed-off-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
---
mount.cifs.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 102 insertions(+), 0 deletions(-)
diff --git a/mount.cifs.c b/mount.cifs.c
index 147f7fc..d9bf0b9 100644
--- a/mount.cifs.c
+++ b/mount.cifs.c
@@ -42,6 +42,7 @@
#include <fcntl.h>
#include <limits.h>
#include <paths.h>
+#include <libgen.h>
#include <sys/mman.h>
#include <sys/wait.h>
#ifdef HAVE_LIBCAP_NG
@@ -161,6 +162,7 @@
#define OPT_BKUPUID 30
#define OPT_BKUPGID 31
+#define MNT_TMP_FILE "/.mtab.tmp.XXXXXX"
/* struct for holding parsed mount info for use by privleged process */
struct parsed_mount_info {
@@ -1624,6 +1626,101 @@ add_mtab_exit:
return rc;
}
+static int
+del_mtab(char *mountpoint)
+{
+ int fd, tmprc, rc = 0;
+ FILE *mnttmp, *mntmtab;
+ struct mntent *mountent;
+ struct stat statbuf;
+ char *mtabfile, *mtabdir, *tmpfile;
+
+ mtabfile = strdup(MOUNTED);
+ mtabdir = dirname(mtabfile);
+ if (!mtabdir) {
+ fprintf(stderr, "del_mtab: cannot determine current mtab path");
+ rc = EX_FILEIO;
+ goto del_mtab_exit;
+ }
+
+ tmpfile = strcat(mtabdir, MNT_TMP_FILE);
+
+ atexit(unlink(tmpfile));
+ tmpfile = mktemp(tmpfile);
+ if (!tmpfile) {
+ fprintf(stderr, "del_mtab: cannot setup tmp file destination");
+ rc = EX_FILEIO;
+ goto del_mtab_exit;
+ }
+
+ atexit(unlock_mtab);
+ rc = lock_mtab();
+ if (rc) {
+ fprintf(stderr, "del_mtab: cannot lock mtab");
+ rc = EX_FILEIO;
+ goto del_mtab_exit;
+ }
+
+ mntmtab = setmntent(MOUNTED, "r");
+ if (!mntmtab) {
+ fprintf(stderr, "del_mtab: could not update mount table\n");
+ rc = EX_FILEIO;
+ goto del_mtab_exit;
+ }
+
+ mnttmp = setmntent(tmpfile, "w");
+ if (!mnttmp) {
+ fprintf(stderr, "del_mtab: could not update mount table\n");
+ endmntent(mntmtab);
+ rc = EX_FILEIO;
+ goto del_mtab_exit;
+ }
+
+ fd = fileno(mntmtab);
+ if (fd < 0) {
+ fprintf(stderr, "del_mtab: mntent does not appear to be valid\n");
+ endmntent(mntmtab);
+ endmntent(mnttmp);
+ rc = EX_FILEIO;
+ goto del_mtab_exit;
+ }
+
+ while ((mountent = getmntent(mntmtab)) != NULL) {
+ if (!strcmp(mountent->mnt_dir,mountpoint))
+ continue;
+ rc = addmntent(mnttmp, mountent);
+ if (rc) {
+ fprintf(stderr, "del_mtab: unable to add mount entry to mtab\n");
+ ftruncate(fd, statbuf.st_size);
+ rc = EX_FILEIO;
+ break;
+ }
+ }
+
+ rc = fstat(fd, &statbuf);
+ if (rc != 0) {
+ fprintf(stderr, "del_mtab: unable to fstat open mtab\n");
+ endmntent(mntmtab);
+ endmntent(mnttmp);
+ rc = EX_FILEIO;
+ goto del_mtab_exit;
+ }
+
+ tmprc = my_endmntent(mntmtab, statbuf.st_size);
+ if (tmprc) {
+ fprintf(stderr, "del_mtab: error %d detected on close of mtab\n", tmprc);
+ rc = EX_FILEIO;
+ }
+ endmntent(mnttmp);
+
+ rename(tmpfile, MOUNTED);
+ unlink(tmpfile);
+
+del_mtab_exit:
+ unlock_mtab();
+ return rc;
+}
+
/* have the child drop root privileges */
static int
drop_child_privs(void)
@@ -2021,6 +2118,11 @@ mount_retry:
}
do_mtab:
+ if (parsed_info->flags & MS_REMOUNT){
+ rc = del_mtab(mountpoint);
+ if (rc)
+ goto mount_exit;
+ }
if (!parsed_info->nomtab && !mtab_unusable())
rc = add_mtab(orig_dev, mountpoint, parsed_info->flags, fstype);
--
1.7.6.4
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