From 5c60a0eab5155043f58fa88909d89e0b06cad2f8 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Tue, 31 May 2011 18:01:36 +0200
Subject: [PATCH] libmount: add mnt_table_is_mounted()
Signed-off-by: Karel Zak <kzak@redhat.com>
---
shlibs/mount/src/libmount.h.in | 3 +
shlibs/mount/src/libmount.sym | 1 +
shlibs/mount/src/tab.c | 210 ++++++++++++++++++++++++++++++++++++++++
shlibs/mount/src/tab_update.c | 2 +-
4 files changed, 215 insertions(+), 1 deletions(-)
diff --git a/shlibs/mount/src/libmount.h.in b/shlibs/mount/src/libmount.h.in
index 3ea2f92..1522208 100644
--- a/shlibs/mount/src/libmount.h.in
+++ b/shlibs/mount/src/libmount.h.in
@@ -308,6 +308,9 @@ extern int mnt_table_find_next_fs(struct libmnt_table *tb,
int (*match_func)(struct libmnt_fs *, void *), void *userdata,
struct libmnt_fs **fs);
+extern int mnt_table_is_fs_mounted(struct libmnt_table *tb, struct libmnt_fs *fstab_fs);
+
+
/* tab_update.c */
extern struct libmnt_update *mnt_new_update(void);
extern void mnt_free_update(struct libmnt_update *upd);
diff --git a/shlibs/mount/src/libmount.sym b/shlibs/mount/src/libmount.sym
index 0b7c560..a498916 100644
--- a/shlibs/mount/src/libmount.sym
+++ b/shlibs/mount/src/libmount.sym
@@ -195,6 +195,7 @@ global:
mnt_update_is_ready;
mnt_update_set_fs;
mnt_update_table;
+ mnt_table_is_fs_mounted;
local:
*;
};
diff --git a/shlibs/mount/src/tab.c b/shlibs/mount/src/tab.c
index 2a6a235..38a5d5b 100644
--- a/shlibs/mount/src/tab.c
+++ b/shlibs/mount/src/tab.c
@@ -712,6 +712,175 @@ struct libmnt_fs *mnt_table_find_pair(struct libmnt_table *tb, const char *sourc
return NULL;
}
+/*
+ * @tb: /proc/self/mountinfo
+ * @fs: filesystem
+ * @mountflags: MS_BIND or 0
+ * @fsroot: fs-root that will be probably used in the mountinfo file
+ * for @fs after mount(2)
+ *
+ * For btrfs subvolumes this function returns NULL, but @fsroot properly set.
+ *
+ * Returns: entry from @tb that will be used as a source for @fs if the @fs is
+ * bindmount.
+ */
+struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
+ struct libmnt_fs *fs,
+ unsigned long mountflags,
+ char **fsroot)
+{
+ char *root = NULL, *mnt = NULL;
+ const char *fstype;
+ struct libmnt_fs *src_fs = NULL;
+
+ assert(tb);
+ assert(fs);
+ assert(fsroot);
+
+ DBG(TAB, mnt_debug("lookup fs-root for %s", mnt_fs_get_source(fs)));
+
+ fstype = mnt_fs_get_fstype(fs);
+
+ if (mountflags & MS_BIND) {
+ const char *src, *src_root;
+
+ DBG(TAB, mnt_debug("fs-root for bind"));
+
+ src = mnt_resolve_spec(mnt_fs_get_source(fs), tb->cache);
+ if (!src)
+ goto err;
+
+ mnt = mnt_get_mountpoint(src);
+ if (!mnt)
+ goto err;
+
+ root = mnt_get_fs_root(src, mnt);
+
+ src_fs = mnt_table_find_target(tb, mnt, MNT_ITER_BACKWARD);
+ if (!src_fs) {
+ DBG(TAB, mnt_debug("not found '%s' in mountinfo -- using default", mnt));
+ goto dflt;
+ }
+
+ /* on btrfs the subvolume is used as fs-root in
+ * /proc/self/mountinfo, so we have to get the original subvolume
+ * name from src_fs and prepend the subvolume name to the
+ * fs-root path
+ */
+ src_root = mnt_fs_get_root(src_fs);
+ if (src_root && !startswith(root, src_root)) {
+ size_t sz = strlen(root) + strlen(src_root) + 1;
+ char *tmp = malloc(sz);
+
+ if (!tmp)
+ goto err;
+ snprintf(tmp, sz, "%s%s", src_root, root);
+ free(root);
+ root = tmp;
+ }
+ }
+
+ /*
+ * btrfs-subvolume mount -- get subvolume name and use it as a root-fs path
+ */
+ else if (fstype && !strcmp(fstype, "btrfs")) {
+ char *vol = NULL, *p;
+ size_t sz, volsz = 0;
+
+ if (mnt_fs_get_option(fs, "subvol", &vol, &volsz))
+ goto dflt;
+
+ DBG(TAB, mnt_debug("setting FS root: btrfs subvol"));
+
+ sz = volsz;
+ if (*vol != '/')
+ sz++;
+ root = malloc(sz + 1);
+ if (!root)
+ goto err;
+ p = root;
+ if (*vol != '/')
+ *p++ = '/';
+ memcpy(p, vol, volsz);
+ *(root + sz) = '\0';
+ }
+dflt:
+ if (!root) {
+ root = strdup("/");
+ if (!root)
+ goto err;
+ }
+ *fsroot = root;
+
+ DBG(TAB, mnt_debug("FS root result: %s", root));
+
+ free(mnt);
+ return src_fs;
+err:
+ free(root);
+ free(mnt);
+ return NULL;
+}
+
+/**
+ * mnt_table_is_mounted:
+ * @tb: /proc/self/mountinfo file
+ * @fstab_fs: /etc/fstab entry
+ *
+ * Checks if the @fstab_fs entry is already in the @tb table. The "swap"
+ * is ignored.
+ *
+ * TODO: check for loopdev (see mount/mount.c is_fstab_entry_mounted().
+ *
+ * Returns: 0 or 1
+ */
+int mnt_table_is_fs_mounted(struct libmnt_table *tb, struct libmnt_fs *fstab_fs)
+{
+ char *root = NULL;
+ struct libmnt_fs *src_fs;
+ const char *src, *tgt;
+ int flags = 0, rc = 0;
+
+ assert(tb);
+ assert(fstab_fs);
+
+ if (fstab_fs->flags & MNT_FS_SWAP)
+ return 0;
+
+ if (mnt_fs_get_option(fstab_fs, "bind", NULL, NULL) == 0)
+ flags = MS_BIND;
+
+ src_fs = mnt_table_get_fs_root(tb, fstab_fs, flags, &root);
+ if (src_fs)
+ src = mnt_fs_get_srcpath(src_fs);
+ else
+ src = mnt_resolve_spec(mnt_fs_get_source(fstab_fs), tb->cache);
+
+ tgt = mnt_fs_get_target(fstab_fs);
+
+ if (tgt || src || root) {
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs;
+
+ mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ const char *s = mnt_fs_get_srcpath(fs),
+ *t = mnt_fs_get_target(fs),
+ *r = mnt_fs_get_root(fs);
+
+ if (s && t && r && !strcmp(t, tgt) &&
+ !strcmp(s, src) && !strcmp(r, root))
+ break;
+ }
+ if (fs)
+ rc = 1; /* success */
+ }
+
+ free(root);
+ return rc;
+}
+
#ifdef TEST_PROGRAM
static int parser_errcb(struct libmnt_table *tb, const char *filename, int line)
@@ -869,6 +1038,46 @@ done:
return rc;
}
+static int test_is_mounted(struct libmnt_test *ts, int argc, char *argv[])
+{
+ struct libmnt_table *tb = NULL, *fstab = NULL;
+ struct libmnt_fs *fs;
+ struct libmnt_iter *itr = NULL;
+ int rc;
+
+ tb = mnt_new_table_from_file("/proc/self/mountinfo");
+ if (!tb) {
+ fprintf(stderr, "failed to parse mountinfo\n");
+ return -1;
+ }
+
+ fstab = create_table(argv[1]);
+ if (!fstab)
+ goto done;
+
+ itr = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!itr)
+ goto done;
+
+ while(mnt_table_next_fs(fstab, itr, &fs) == 0) {
+ if (mnt_table_is_fs_mounted(tb, fs))
+ printf("%s already mounted on %s\n",
+ mnt_fs_get_source(fs),
+ mnt_fs_get_target(fs));
+ else
+ printf("%s not mounted on %s\n",
+ mnt_fs_get_source(fs),
+ mnt_fs_get_target(fs));
+ }
+
+ rc = 0;
+done:
+ mnt_free_table(tb);
+ mnt_free_table(fstab);
+ mnt_free_iter(itr);
+ return rc;
+}
+
int main(int argc, char *argv[])
{
struct libmnt_test tss[] = {
@@ -877,6 +1086,7 @@ int main(int argc, char *argv[])
{ "--find-backward", test_find_bw, "<file> <source|target> <string>" },
{ "--find-pair", test_find_pair, "<file> <source> <target>" },
{ "--copy-fs", test_copy_fs, "<file> copy root FS from the file" },
+ { "--is-mounted", test_is_mounted, "<fstab> check what from <file> are already mounted" },
{ NULL }
};
diff --git a/shlibs/mount/src/tab_update.c b/shlibs/mount/src/tab_update.c
index 5abb566..9817f20 100644
--- a/shlibs/mount/src/tab_update.c
+++ b/shlibs/mount/src/tab_update.c
@@ -410,7 +410,7 @@ static int set_fs_root(struct libmnt_fs *result, struct libmnt_fs *fs, unsigned
mnt_fs_set_fstype(result, mnt_fs_get_fstype(src_fs));
/* on btrfs the subvolume is used as fs-root in
- * /proc/self/mountinfo, so we have get the original subvolume
+ * /proc/self/mountinfo, so we have to get the original subvolume
* name from src_fs and prepend the subvolume name to the
* fs-root path
*/
--
1.7.5.2