From: Karel Zak <kzak@redhat.com>
Date: Wed, 22 Dec 2010 12:15:04 +0000 (+0100)
Subject: libmount: better work with mtab options
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f84fa6f7b98dd00ef6f196815b18590ca50c3528;p=util-linux

libmount: better work with mtab options

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/shlibs/mount/src/fs.c b/shlibs/mount/src/fs.c
index 94c35355..21e02f3d 100644
--- a/shlibs/mount/src/fs.c
+++ b/shlibs/mount/src/fs.c
@@ -145,6 +145,60 @@ err:
 	return NULL;
 }
 
+/**
+ * mnt_copy_mtab_fs:
+ * @fs: filesystem
+ *
+ * This function copies all @fs description except information that does not
+ * belong to /etc/mtab (e.g. VFS and userspace mount options with MNT_NOMTAB
+ * mask).
+ *
+ * Returns: copy of @fs.
+ */
+mnt_fs *mnt_copy_mtab_fs(const mnt_fs *fs)
+{
+	mnt_fs *n = mnt_new_fs();
+
+	if (!n)
+		return NULL;
+
+	if (cpy_str_at_offset(n, fs, offsetof(struct _mnt_fs, source)))
+		goto err;
+	if (cpy_str_at_offset(n, fs, offsetof(struct _mnt_fs, target)))
+		goto err;
+	if (cpy_str_at_offset(n, fs, offsetof(struct _mnt_fs, fstype)))
+		goto err;
+
+	if (fs->vfs_optstr) {
+		char *p = NULL;
+		mnt_optstr_get_options(fs->vfs_optstr, &p,
+				mnt_get_builtin_optmap(MNT_LINUX_MAP),
+				MNT_NOMTAB);
+		n->vfs_optstr = p;
+	}
+
+	if (fs->user_optstr) {
+		char *p = NULL;
+		mnt_optstr_get_options(fs->user_optstr, &p,
+				mnt_get_builtin_optmap(MNT_USERSPACE_MAP),
+				MNT_NOMTAB);
+		n->user_optstr = p;
+	}
+
+	if (cpy_str_at_offset(n, fs, offsetof(struct _mnt_fs, fs_optstr)))
+		goto err;
+
+	n->freq       = fs->freq;
+	n->passno     = fs->passno;
+	n->flags      = fs->flags;
+
+	return n;
+err:
+	mnt_free_fs(n);
+	return NULL;
+
+}
+
 /**
  * mnt_fs_get_userdata:
  * @fs: mnt_file instance
diff --git a/shlibs/mount/src/mount.h.in b/shlibs/mount/src/mount.h.in
index e0212fa5..76d66aaa 100644
--- a/shlibs/mount/src/mount.h.in
+++ b/shlibs/mount/src/mount.h.in
@@ -65,7 +65,7 @@ struct mnt_optmap
 {
 	const char	*name;	 /* option name[=%<type>] (e.g. "loop[=%s]") */
 	int		id;	 /* option ID or MS_* flags (e.g MS_RDONLY) */
-	int		mask;	 /* MNT_{MFLAG,MDATA,INVMASK,...} mask */
+	int		mask;	 /* MNT_{NOMTAB,INVERT,...} mask */
 };
 
 /*
@@ -167,6 +167,9 @@ extern int mnt_split_optstr(const char *optstr,
 			    char **user, char **vfs, char **fs,
 			    int ifnore_user, int ignore_vfs);
 
+extern int mnt_optstr_get_options(const char *optstr, char **subset,
+                            const struct mnt_optmap *map, int ignore);
+
 extern int mnt_optstr_get_flags(const char *optstr, unsigned long *flags,
 				const struct mnt_optmap *map);
 extern int mnt_optstr_apply_flags(char **optstr, unsigned long flags,
@@ -204,6 +207,7 @@ extern int mnt_lock_file(mnt_lock *ml);
 extern mnt_fs *mnt_new_fs(void);
 extern void mnt_free_fs(mnt_fs *ent);
 extern mnt_fs *mnt_copy_fs(const mnt_fs *fs);
+extern mnt_fs *mnt_copy_mtab_fs(const mnt_fs *fs);
 extern void *mnt_fs_get_userdata(mnt_fs *fs);
 extern int mnt_fs_set_userdata(mnt_fs *fs, void *data);
 extern const char *mnt_fs_get_source(mnt_fs *ent);
@@ -314,6 +318,7 @@ extern int mnt_update_tab(mnt_update *upd, mnt_lock *lc);
 extern unsigned long mnt_update_get_mountflags(mnt_update *upd);
 extern int mnt_update_force_rdonly(mnt_update *upd, int rdonly);
 extern const char *mnt_update_get_filename(mnt_update *upd);
+extern mnt_fs *mnt_update_get_fs(mnt_update *upd);
 
 /* context.c */
 
diff --git a/shlibs/mount/src/mount.sym b/shlibs/mount/src/mount.sym
index 7890a140..3d2475ba 100644
--- a/shlibs/mount/src/mount.sym
+++ b/shlibs/mount/src/mount.sym
@@ -136,7 +136,7 @@ global:
 	mnt_update_get_mountflags;
 	mnt_update_force_rdonly;
 	mnt_update_get_filename;
-
+	mnt_update_get_fs;
 local:
 	*;
 };
diff --git a/shlibs/mount/src/mountP.h b/shlibs/mount/src/mountP.h
index 3403ab70..fe6ea569 100644
--- a/shlibs/mount/src/mountP.h
+++ b/shlibs/mount/src/mountP.h
@@ -84,8 +84,8 @@ mnt_debug_h(void *handler, const char *mesg, ...)
 }
 
 #else /* !CONFIG_LIBMOUNT_DEBUG */
-# define DBG(m,x)
-# define DBG_FLUSH
+# define DBG(m,x) do { ; } while(0)
+# define DBG_FLUSH do { ; } while(0)
 #endif
 
 /* extension for files in the /etc/fstab.d directory */
diff --git a/shlibs/mount/src/optmap.c b/shlibs/mount/src/optmap.c
index d5f64109..38256b09 100644
--- a/shlibs/mount/src/optmap.c
+++ b/shlibs/mount/src/optmap.c
@@ -99,7 +99,7 @@ static const struct mnt_optmap linux_flags_map[] =
    { "async",    MS_SYNCHRONOUS, MNT_INVERT },/* asynchronous I/O */
 
    { "dirsync",  MS_DIRSYNC },                /* synchronous directory modifications */
-   { "remount",  MS_REMOUNT },                /* Alter flags of mounted FS */
+   { "remount",  MS_REMOUNT, MNT_NOMTAB },    /* alter flags of mounted FS */
    { "bind",     MS_BIND },                   /* Remount part of tree elsewhere */
    { "rbind",    MS_BIND | MS_REC },          /* Idem, plus mounted subtrees */
 #ifdef MS_NOSUB
diff --git a/shlibs/mount/src/optstr.c b/shlibs/mount/src/optstr.c
index 62c5701d..7c41f685 100644
--- a/shlibs/mount/src/optstr.c
+++ b/shlibs/mount/src/optstr.c
@@ -147,7 +147,6 @@ static int mnt_optstr_locate_option(char *optstr, const char *name,
 		}
 	} while(1);
 
-	DBG(OPTIONS, mnt_debug("can't found '%s' option", name));
 	return rc;
 }
 
@@ -513,6 +512,59 @@ int mnt_split_optstr(const char *optstr, char **user, char **vfs, char **fs,
 	return 0;
 }
 
+/**
+ * mnt_optstr_get_options
+ * @optstr: string with comma separated list of options
+ * @subset: returns newly allocated string with options
+ * @map: options map
+ * @ignore: mask of the options that should be ignored
+ *
+ * Extracts options from @optstr that belongs to the @map, for example:
+ *
+ *	 mnt_split_optstr_by_map(optstr, &p,
+ *			mnt_get_builtin_optmap(MNT_LINUX_MAP),
+ *			MNT_NOMTAB);
+ *
+ * returns all VFS options, the options that does not belong to mtab
+ * are ignored.
+ *
+ * Returns: 0 on success, or negative number in case of error.
+ */
+int mnt_optstr_get_options(const char *optstr, char **subset,
+			    const struct mnt_optmap *map, int ignore)
+{
+	struct mnt_optmap const *maps[1];
+	char *name, *val, *str = (char *) optstr;
+	size_t namesz, valsz;
+
+	if (!optstr || !subset)
+		return -EINVAL;
+
+	maps[0] = map;
+	*subset = NULL;
+
+	while(!mnt_optstr_next_option(&str, &name, &namesz, &val, &valsz)) {
+		int rc = 0;
+		const struct mnt_optmap *ent;
+
+		mnt_optmap_get_entry(maps, 1, name, namesz, &ent);
+
+		if (!ent || !ent->id)
+			continue;	/* ignore undefined options (comments) */
+
+		if (ignore && (ent->mask & ignore))
+			continue;
+		rc = __mnt_optstr_append_option(subset, name, namesz, val, valsz);
+		if (rc) {
+			free(*subset);
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+
 /**
  * mnt_optstr_get_flags:
  * @optstr: string with comma separated list of options
diff --git a/shlibs/mount/src/tab_parse.c b/shlibs/mount/src/tab_parse.c
index a6c14fff..335f703a 100644
--- a/shlibs/mount/src/tab_parse.c
+++ b/shlibs/mount/src/tab_parse.c
@@ -469,7 +469,7 @@ mnt_tab *__mnt_new_tab_from_file(const char *filename, int fmt)
 
 	if (!filename)
 		return NULL;
-	if (stat(filename, &st) || st.st_size == 0)
+	if (stat(filename, &st))
 		return NULL;
 	tb = mnt_new_tab();
 	if (tb) {
diff --git a/shlibs/mount/src/tab_update.c b/shlibs/mount/src/tab_update.c
index 603b6689..986eff8e 100644
--- a/shlibs/mount/src/tab_update.c
+++ b/shlibs/mount/src/tab_update.c
@@ -201,9 +201,10 @@ int mnt_update_set_fs(mnt_update *upd, unsigned long mountflags,
 			if (rc)
 				return rc;
 		} else {
-			upd->fs = mnt_copy_fs(fs);
+			upd->fs = mnt_copy_mtab_fs(fs);
 			if (!upd->fs)
 				return -ENOMEM;
+
 		}
 	}
 
@@ -214,7 +215,10 @@ int mnt_update_set_fs(mnt_update *upd, unsigned long mountflags,
 }
 
 /**
- * Returns update filesystem or NULL
+ * mnt_update_get_fs:
+ * @upd: update
+ *
+ * Returns: update filesystem entry or NULL
  */
 mnt_fs *mnt_update_get_fs(mnt_update *upd)
 {
@@ -283,6 +287,7 @@ static int utab_new_entry(mnt_fs *fs, unsigned long mountflags, mnt_fs **ent)
 {
 	int rc = 0;
 	const char *o = NULL, *a = NULL;
+	char *u = NULL;
 
 	assert(fs);
 	assert(ent);
@@ -297,8 +302,19 @@ static int utab_new_entry(mnt_fs *fs, unsigned long mountflags, mnt_fs **ent)
 	o = mnt_fs_get_userspace_options(fs);
 	a = mnt_fs_get_attributes(fs);
 
-	if (!o && !a)
-		return 1;	/* don't have mount options */
+	if (o) {
+		/* remove non-mtab options */
+		rc = mnt_optstr_get_options(o, &u,
+				mnt_get_builtin_optmap(MNT_USERSPACE_MAP),
+				MNT_NOMTAB);
+		if (rc)
+			goto err;
+	}
+
+	if (!u && !a) {
+		DBG(UPDATE, mnt_debug("utab entry unnecessary (no options)"));
+		return 1;
+	}
 
 	/* allocate the entry */
 	*ent = mnt_copy_fs(fs);
@@ -307,7 +323,7 @@ static int utab_new_entry(mnt_fs *fs, unsigned long mountflags, mnt_fs **ent)
 		goto err;
 	}
 
-	rc = mnt_fs_set_userspace_options(*ent, o);
+	rc = mnt_fs_set_userspace_options(*ent, u);
 	if (rc)
 		goto err;
 	rc = mnt_fs_set_attributes(*ent, a);
@@ -320,10 +336,12 @@ static int utab_new_entry(mnt_fs *fs, unsigned long mountflags, mnt_fs **ent)
 			goto err;
 	}
 
+	free(u);
 	DBG(UPDATE, mnt_debug("utab entry OK"));
 	return 0;
 err:
 	mnt_free_fs(*ent);
+	free(u);
 	*ent = NULL;
 	return rc;
 }
@@ -349,6 +367,8 @@ static int set_fs_root(mnt_fs *result, mnt_fs *fs, unsigned long mountflags)
 		const char *src, *src_root;
 		mnt_fs *src_fs;
 
+		DBG(UPDATE, mnt_debug("setting FS root: bind"));
+
 		src = mnt_fs_get_srcpath(fs);
 		if (src) {
 			rc = mnt_fs_set_bindsrc(result, src);
@@ -363,11 +383,15 @@ static int set_fs_root(mnt_fs *result, mnt_fs *fs, unsigned long mountflags)
 		root = mnt_get_fs_root(src, mnt);
 
 		tb = __mnt_new_tab_from_file(_PATH_PROC_MOUNTINFO, MNT_FMT_MOUNTINFO);
-		if (!tb)
+		if (!tb) {
+			DBG(UPDATE, mnt_debug("failed to parse mountinfo -- using default"));
 			goto dflt;
+		}
 		src_fs = mnt_tab_find_target(tb, mnt, MNT_ITER_BACKWARD);
-		if (!src_fs)
+		if (!src_fs)  {
+			DBG(UPDATE, mnt_debug("not found '%s' in mountinfo -- using default", mnt));
 			goto dflt;
+		}
 
 		/* set device name and fs */
 		src = mnt_fs_get_srcpath(src_fs);
@@ -405,6 +429,8 @@ static int set_fs_root(mnt_fs *result, mnt_fs *fs, unsigned long mountflags)
 		if (mnt_fs_get_option(fs, "subvol", &vol, &volsz))
 			goto dflt;
 
+		DBG(UPDATE, mnt_debug("setting FS root: btrfs subvol"));
+
 		sz = volsz;
 		if (*vol != '/')
 			sz++;
@@ -762,7 +788,9 @@ int mnt_update_tab(mnt_update *upd, mnt_lock *lc)
 		return 0;
 
 	DBG(UPDATE, mnt_debug_h(upd, "%s: update tab", upd->filename));
-	DBG(UPDATE, mnt_fs_print_debug(upd->fs, stderr));
+	if (upd->fs) {
+		DBG(UPDATE, mnt_fs_print_debug(upd->fs, stderr));
+	}
 
 	if (!upd->fs && upd->target)
 		rc = update_remove_entry(upd, lc);	/* umount */
diff --git a/shlibs/mount/src/utils.c b/shlibs/mount/src/utils.c
index 96ce7ddb..ff3c90cd 100644
--- a/shlibs/mount/src/utils.c
+++ b/shlibs/mount/src/utils.c
@@ -722,7 +722,7 @@ char *mnt_get_mountpoint(const char *path)
 
 	memcpy(mnt, "/", 2);
 done:
-	DBG(UTILS, mnt_debug("fs-root for %s is %s", path, mnt));
+	DBG(UTILS, mnt_debug("%s mountpoint is %s", path, mnt));
 	return mnt;
 err:
 	free(mnt);
@@ -731,7 +731,7 @@ err:
 
 char *mnt_get_fs_root(const char *path, const char *mnt)
 {
-	char *m = (char *) mnt;
+	char *m = (char *) mnt, *res;
 	const char *p;
 	size_t sz;
 
@@ -746,7 +746,9 @@ char *mnt_get_fs_root(const char *path, const char *mnt)
 	if (m != mnt)
 		free(m);
 
-	return *p ? strdup(p) : strdup("/");
+	res = *p ? strdup(p) : strdup("/");
+	DBG(UTILS, mnt_debug("%s fs-root is %s", path, res));
+	return res;
 }
 
 #ifdef TEST_PROGRAM