libmount: support /{proc,etc}/filesystems

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

7 files changed, 241 insertions, 39 deletions

diff --git a/shlibs/mount/src/context.c b/shlibs/mount/src/context.c
index b4662d89e..3863629ca 100644
--- a/shlibs/mount/src/context.c
+++ b/shlibs/mount/src/context.c
@@ -33,6 +33,9 @@ mnt_context *mnt_new_context()
 	ruid = getuid();
 	euid = geteuid();
 
+	cxt->syscall_status = 1;	/* not called yet */
+	cxt->helper_exec_status = 1;
+
 	/* if we're really root and aren't running setuid */
 	cxt->restricted = (uid_t) 0 == ruid && ruid == euid ? 0 : 1;
 
@@ -115,13 +118,15 @@ int mnt_reset_context(mnt_context *cxt)
 
 	cxt->fs = NULL;
 	cxt->mtab = NULL;
+	cxt->ambi = 0;
 	cxt->helper = NULL;
 	cxt->orig_user = NULL;
 	cxt->mountflags = 0;
 	cxt->user_mountflags = 0;
 	cxt->mountdata = NULL;
 	cxt->flags = MNT_FL_DEFAULT;
-	cxt->syscall_errno = 0;
+	cxt->syscall_status = 1;
+	cxt->helper_exec_status = 1;
 	cxt->helper_status = 0;
 
 	/* restore non-resetable flags */
@@ -418,6 +423,8 @@ int mnt_context_set_target(mnt_context *cxt, const char *target)
  */
 int mnt_context_set_fstype(mnt_context *cxt, const char *fstype)
 {
+	if (fstype && strchr(fstype, ','))
+		return -EINVAL;
 	return mnt_fs_set_fstype(mnt_context_get_fs(cxt), fstype);
 }
 
@@ -909,6 +916,9 @@ int mnt_context_guess_fstype(mnt_context *cxt)
 		goto done;
 	if (cxt->flags & MS_REMOUNT)
 		goto none;
+	if (cxt->fstype_pattern)
+		goto done;
+
 	dev = mnt_fs_get_srcpath(cxt->fs);
 	if (!dev)
 		goto err;
@@ -931,7 +941,7 @@ int mnt_context_guess_fstype(mnt_context *cxt)
 	if (rc)
 		goto err;
 done:
-	DBG(CXT, mnt_debug_h(cxt, "detected FS type: %s",
+	DBG(CXT, mnt_debug_h(cxt, "FS type: %s",
 				mnt_fs_get_fstype(cxt->fs)));
 	return 0;
 none:
@@ -1159,6 +1169,15 @@ static int apply_tab(mnt_context *cxt, mnt_tab *tb, int direction)
 	return rc;
 }
 
+/**
+ * mnt_context_apply_fstab:
+ * @cxt: mount context
+ *
+ * This function is optional if mnt_context_do_mount() is used. See also
+ * mnt_context_set_optsmode().
+ *
+ * Returns: 0 on success, negative number in case of error.
+ */
 int mnt_context_apply_fstab(mnt_context *cxt)
 {
 	int rc;
@@ -1209,13 +1228,23 @@ int mnt_context_apply_fstab(mnt_context *cxt)
 			goto err;
 	}
 	return 0;
-
 err:
 	DBG(CXT, mnt_debug_h(cxt, "failed to found entry in fstab/mtab"));
 	return rc;
 }
 
 /**
+ * mnt_context_get_status:
+ * @cxt: mount context
+ *
+ * Returns: 1 if mount.<type> or mount(2) syscall was successfull or 0.
+ */
+int mnt_context_get_status(mnt_context *cxt)
+{
+	return cxt && (!cxt->syscall_status || !cxt->helper_exec_status);
+}
+
+/**
  * mnt_context_strerror
  * @cxt: context
  * @buf: buffer
diff --git a/shlibs/mount/src/context_mount.c b/shlibs/mount/src/context_mount.c
index de6557df4..070d72f10 100644
--- a/shlibs/mount/src/context_mount.c
+++ b/shlibs/mount/src/context_mount.c
@@ -257,8 +257,8 @@ static int exec_helper(mnt_context *cxt)
 
 		type = mnt_fs_get_fstype(cxt->fs);
 
-		args[i++] = cxt->helper;			/* 1 */
-		args[i++] = mnt_fs_get_srcpath(cxt->fs);	/* 2 */
+		args[i++] = cxt->helper;		/* 1 */
+		args[i++] = mnt_fs_get_srcpath(cxt->fs);/* 2 */
 		args[i++] = mnt_fs_get_target(cxt->fs);	/* 3 */
 
 		if (cxt->flags & MNT_FL_SLOPPY)
@@ -296,12 +296,12 @@ static int exec_helper(mnt_context *cxt)
 
 		DBG(CXT, mnt_debug_h(cxt, "%s executed [status=%d]",
 					cxt->helper, cxt->helper_status));
-		rc = 0;
+		cxt->helper_exec_status = rc = 0;
 		break;
 	}
 
 	case -1:
-		rc = -errno;
+		cxt->helper_exec_status = rc = -errno;
 		DBG(CXT, mnt_debug_h(cxt, "fork() failed"));
 		break;
 	}
@@ -315,7 +315,7 @@ static int exec_helper(mnt_context *cxt)
  */
 static int do_mount(mnt_context *cxt, const char *try_type)
 {
-	int rc;
+	int rc = 0;
 	const char *src, *target, *type;
 	unsigned long flags;
 
@@ -323,6 +323,7 @@ static int do_mount(mnt_context *cxt, const char *try_type)
 	assert(cxt->fs);
 	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
 
+
 	if (try_type && !cxt->helper) {
 		rc = mnt_context_prepare_helper(cxt, "mount", try_type);
 		if (!rc)
@@ -331,8 +332,6 @@ static int do_mount(mnt_context *cxt, const char *try_type)
 	if (cxt->helper)
 		return exec_helper(cxt);
 
-	type = try_type ? : mnt_fs_get_fstype(cxt->fs);
-
 	flags = cxt->mountflags;
 	src = mnt_fs_get_srcpath(cxt->fs);
 	target = mnt_fs_get_target(cxt->fs);
@@ -340,6 +339,8 @@ static int do_mount(mnt_context *cxt, const char *try_type)
 	if (!src || !target)
 		return -EINVAL;
 
+	type = try_type ? : mnt_fs_get_fstype(cxt->fs);
+
 	if (!(flags & MS_MGC_MSK))
 		flags |= MS_MGC_VAL;
 
@@ -352,14 +353,68 @@ static int do_mount(mnt_context *cxt, const char *try_type)
 
 	if (!(cxt->flags & MNT_FL_FAKE)) {
 		if (mount(src, target, type, flags, cxt->mountdata)) {
-			cxt->syscall_errno = errno;
+			cxt->syscall_status = -errno;
 			DBG(CXT, mnt_debug_h(cxt, "mount(2) failed [errno=%d]",
-							cxt->syscall_errno));
-			return -cxt->syscall_errno;
+							-cxt->syscall_status));
+			return cxt->syscall_status;
 		}
 		DBG(CXT, mnt_debug_h(cxt, "mount(2) success"));
+		cxt->syscall_status = 0;
 	}
-	return 0;
+
+	if (try_type && cxt->update) {
+		mnt_fs *fs = mnt_update_get_fs(cxt->update);
+		if (fs)
+			rc = mnt_fs_set_fstype(fs, try_type);
+	}
+	return rc;
+}
+
+static int do_mount_by_pattern(mnt_context *cxt, const char *pattern)
+{
+	int neg = pattern && strncmp(pattern, "no", 2) == 0;
+	int rc = -EINVAL;
+	char **filesystems, **fp;
+
+	assert(cxt);
+
+	if (!neg && pattern) {
+		/*
+		 * try all types from the list
+		 */
+		char *p, *p0;
+
+		p0 = p = strdup(pattern);
+		if (!p)
+			return -ENOMEM;
+		do {
+			char *end = strchr(p, ',');
+			if (end)
+				*end = '\0';
+			rc = do_mount(cxt, p);
+			p = end ? end + 1 : NULL;
+		} while (!mnt_context_get_status(cxt) && p);
+
+		free(p0);
+
+		if (mnt_context_get_status(cxt))
+			return rc;
+	}
+
+	/*
+	 * try /etc/filesystems and /proc/filesystems
+	 */
+	rc = mnt_get_filesystems(&filesystems, neg ? pattern : NULL);
+	if (rc)
+		return rc;
+
+	for (fp = filesystems; *fp; fp++) {
+		rc = do_mount(cxt, *fp);
+		if (mnt_context_get_status(cxt))
+			break;
+	}
+	mnt_free_filesystems(filesystems);
+	return rc;
 }
 
 /**
@@ -370,16 +425,20 @@ static int do_mount(mnt_context *cxt, const char *try_type)
  *
  * See also mnt_context_disable_helpers().
  *
- * Returns: 0 on success, and negative number in case of error.
+ * Returns: 0 on success, and negative number in case of error. WARNING: error
+ *          does not mean that mount(2) syscall or mount.<type> helper wasn't
+ *          sucessfully called. Check mnt_context_get_status() after error!
  */
 int mnt_context_do_mount(mnt_context *cxt)
 {
-	int rc = -EINVAL;
+	int rc = -EINVAL, x;
 	const char *type;
 
 	assert(cxt);
 	assert(cxt->fs);
 	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+	assert(cxt->helper_exec_status == 1);
+	assert(cxt->syscall_status == 1);
 
 	if (!cxt || !cxt->fs || (cxt->fs->flags & MNT_FS_SWAP))
 		return -EINVAL;
@@ -417,21 +476,16 @@ int mnt_context_do_mount(mnt_context *cxt)
 		cxt->mountdata = (char *) mnt_fs_get_fs_optstr(cxt->fs);
 
 	type = mnt_fs_get_fstype(cxt->fs);
-
-	if (type && !strchr(type, ',')) {
+	if (type)
 		rc = do_mount(cxt, NULL);
-		if (rc)
-			return rc;
-	}
-
-	/* TODO: try all filesystems from comma separated list of types */
-
-	/* TODO: try all filesystems from /proc/filesystems and /etc/filesystems */
+	else
+		rc = do_mount_by_pattern(cxt, cxt->fstype_pattern);
 
 	/* TODO: if mtab update is expected then check if the
 	 * target is really mounted read-write to avoid 'ro' in
 	 * mtab and 'rw' in /proc/mounts.
 	 */
-	return mnt_context_update_tabs(cxt);
+	x = mnt_context_update_tabs(cxt);
+	return rc ? rc : x;
 }
 
diff --git a/shlibs/mount/src/context_umount.c b/shlibs/mount/src/context_umount.c
index 476ee515c..87a0bc8ef 100644
--- a/shlibs/mount/src/context_umount.c
+++ b/shlibs/mount/src/context_umount.c
@@ -275,6 +275,7 @@ static int exec_helper(mnt_context *cxt)
 	assert(cxt->fs);
 	assert(cxt->helper);
 	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+	assert(cxt->helper_exec_status == 1);
 
 	DBG_FLUSH;
 
@@ -329,12 +330,12 @@ static int exec_helper(mnt_context *cxt)
 
 		DBG(CXT, mnt_debug_h(cxt, "%s executed [status=%d]",
 					cxt->helper, cxt->helper_status));
-		rc = 0;
+		cxt->helper_exec_status = rc = 0;
 		break;
 	}
 
 	case -1:
-		rc = -errno;
+		cxt->helper_exec_status = rc = -errno;
 		DBG(CXT, mnt_debug_h(cxt, "fork() failed"));
 		break;
 	}
@@ -350,6 +351,7 @@ static int do_umount(mnt_context *cxt)
 	assert(cxt);
 	assert(cxt->fs);
 	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+	assert(cxt->syscall_status == 1);
 
 	if (cxt->helper)
 		return exec_helper(cxt);
@@ -375,38 +377,37 @@ static int do_umount(mnt_context *cxt)
 		rc = umount(target);
 
 	if (rc < 0)
-		cxt->syscall_errno = errno;
-
+		cxt->syscall_status = -errno;
 	/*
 	 * try remount read-only
 	 */
-	if (rc < 0 && cxt->syscall_errno == EBUSY &&
+	if (rc < 0 && cxt->syscall_status == -EBUSY &&
 	    (cxt->flags & MNT_FL_RDONLY_UMOUNT) && src) {
 
 		cxt->mountflags |= MS_REMOUNT | MS_RDONLY;
 		cxt->flags &= ~MNT_FL_LOOPDEL;
 		DBG(CXT, mnt_debug_h(cxt, "umount(2) failed [errno=%d] -- "
 					"tring remount read-only",
-					cxt->syscall_errno));
+					-cxt->syscall_status));
 
 		rc = mount(src, target, NULL,
 			    MS_MGC_VAL | MS_REMOUNT | MS_RDONLY, NULL);
 		if (rc < 0) {
-			cxt->syscall_errno = errno;
+			cxt->syscall_status = -errno;
 			DBG(CXT, mnt_debug_h(cxt, "read-only re-mount(2) failed "
 					"[errno=%d]",
-					cxt->syscall_errno));
-			return -cxt->syscall_errno;
+					-cxt->syscall_status));
+			return cxt->syscall_status;
 		}
-		cxt->syscall_errno = 0;
+		cxt->syscall_status = 0;
 		DBG(CXT, mnt_debug_h(cxt, "read-only re-mount(2) success"));
 		return 0;
 	}
 
 	if (rc < 0) {
 		DBG(CXT, mnt_debug_h(cxt, "umount(2) failed [errno=%d]",
-					cxt->syscall_errno));
-		return -cxt->syscall_errno;
+					-cxt->syscall_status));
+		return -cxt->syscall_status;
 	}
 	DBG(CXT, mnt_debug_h(cxt, "umount(2) success"));
 	return 0;
diff --git a/shlibs/mount/src/mount.h.in b/shlibs/mount/src/mount.h.in
index 8bb44c7b4..5553921ed 100644
--- a/shlibs/mount/src/mount.h.in
+++ b/shlibs/mount/src/mount.h.in
@@ -135,6 +135,9 @@ extern const char *mnt_get_fstab_path(void);
 extern const char *mnt_get_mtab_path(void);
 extern const char *mnt_get_utab_path(void);
 
+extern int mnt_get_filesystems(char ***filesystems, const char *pattern);
+extern void mnt_free_filesystems(char **filesystems);
+
 extern int mnt_has_regular_mtab(const char **mtab, int *writable);
 extern int mnt_has_regular_utab(const char **utab, int *writable);
 
@@ -345,6 +348,7 @@ extern int mnt_context_set_userspace_mountflags(mnt_context *cxt, unsigned long
 extern int mnt_context_get_userspace_mountflags(mnt_context *cxt, unsigned long *flags);
 extern int mnt_context_set_mountdata(mnt_context *cxt, void *data);
 extern int mnt_context_apply_fstab(mnt_context *cxt);
+extern int mnt_context_get_status(mnt_context *cxt);
 
 /*
  * mount(8) userspace options masks (MNT_MAP_USERSPACE map)
diff --git a/shlibs/mount/src/mountP.h b/shlibs/mount/src/mountP.h
index 0f1395e5a..a277d61eb 100644
--- a/shlibs/mount/src/mountP.h
+++ b/shlibs/mount/src/mountP.h
@@ -236,10 +236,11 @@ struct _mnt_context
 
 	char	*helper;	/* name of the used /sbin/[u]mount.<type> helper */
 	int	helper_status;	/* helper wait(2) status */
+	int	helper_exec_status; /* 1: not called yet, 0: success, <0: -errno */
 
 	char	*orig_user;	/* original (non-fixed) user= option */
 
-	int	syscall_errno;	/* mount(2) or umount(2) error */
+	int	syscall_status;	/* 1: not called yet, 0: success, <0: -errno */
 };
 
 /* flags */
@@ -294,4 +295,7 @@ extern mnt_fs *mnt_context_get_fs(mnt_context *cxt);
 extern int mnt_context_merge_mountflags(mnt_context *cxt);
 extern int mnt_context_update_tabs(mnt_context *cxt);
 
+/* tab_update.c */
+extern mnt_fs *mnt_update_get_fs(mnt_update *upd);
+
 #endif /* _LIBMOUNT_PRIVATE_H */
diff --git a/shlibs/mount/src/tab_update.c b/shlibs/mount/src/tab_update.c
index 99b2a890b..4b4f0addd 100644
--- a/shlibs/mount/src/tab_update.c
+++ b/shlibs/mount/src/tab_update.c
@@ -152,6 +152,13 @@ int mnt_update_set_fs(mnt_update *upd, int mountflags,
 	return 0;
 }
 
+/*
+ * Returns update filesystem or NULL
+ */
+mnt_fs *mnt_update_get_fs(mnt_update *upd)
+{
+	return upd ? upd->fs : NULL;
+}
 
 /*
  * Allocates (but does not write) utab entry for mount/remount. This function
diff --git a/shlibs/mount/src/utils.c b/shlibs/mount/src/utils.c
index 0f17edfea..6af8d14f4 100644
--- a/shlibs/mount/src/utils.c
+++ b/shlibs/mount/src/utils.c
@@ -305,6 +305,93 @@ int mnt_match_options(const char *optstr, const char *pattern)
 	return 1;
 }
 
+void mnt_free_filesystems(char **filesystems)
+{
+	char **p;
+
+	if (!filesystems)
+		return;
+	for (p = filesystems; *p; p++)
+		free(*p);
+	free(filesystems);
+}
+
+static int add_filesystem(char ***filesystems, char *name)
+{
+	int n = 0;
+
+	assert(filesystems);
+	assert(name);
+
+	if (*filesystems) {
+		char **p;
+		for (n = 0, p = *filesystems; *p; p++, n++) {
+			if (strcmp(*p, name) == 0)
+				return 0;
+		}
+	}
+
+	#define MYCHUNK	16
+
+	if (n == 0 || !((n + 1) % MYCHUNK)) {
+		size_t items = ((n + 1 + MYCHUNK) / MYCHUNK) * MYCHUNK;
+		char **x = realloc(*filesystems, items * sizeof(char *));
+
+		if (!x)
+			goto err;
+		*filesystems = x;
+	}
+	name = strdup(name);
+	if (!name)
+		goto err;
+	(*filesystems)[n] = name;
+	(*filesystems)[n + 1] = NULL;
+	return 0;
+err:
+	mnt_free_filesystems(*filesystems);
+	return -ENOMEM;
+}
+
+static int get_filesystems(const char *filename, char ***filesystems, const char *pattern)
+{
+	FILE *f;
+	char line[128];
+
+	f = fopen(filename, "r");
+	if (!f)
+		return 0;
+
+	while (fgets(line, sizeof(line), f)) {
+		char name[sizeof(line)];
+		int rc;
+
+		if (*line == '#' || strncmp(line, "nodev", 5) == 0)
+			continue;
+		if (sscanf(line, " %128[^\n ]\n", name) != 1)
+			continue;
+		if (pattern && !mnt_match_fstype(name, pattern))
+			continue;
+		rc = add_filesystem(filesystems, name);
+		if (rc)
+			return rc;
+	}
+	return 0;
+}
+
+int mnt_get_filesystems(char ***filesystems, const char *pattern)
+{
+	int rc;
+
+	if (!filesystems)
+		return -EINVAL;
+	*filesystems = NULL;
+
+	rc = get_filesystems(_PATH_FILESYSTEMS, filesystems, pattern);
+	if (rc)
+		return rc;
+	return get_filesystems(_PATH_PROC_FILESYSTEMS, filesystems, pattern);
+}
+
 /*
  * Returns allocated string with username or NULL.
  */
@@ -721,11 +808,27 @@ int test_fsroot(struct mtest *ts, int argc, char *argv[])
 	return 0;
 }
 
+int test_filesystems(struct mtest *ts, int argc, char *argv[])
+{
+	char **filesystems = NULL;
+	int rc;
+
+	rc = mnt_get_filesystems(&filesystems, argc ? argv[1] : NULL);
+	if (!rc) {
+		char **p;
+		for (p = filesystems; *p; p++)
+			printf("%s\n", *p);
+		mnt_free_filesystems(filesystems);
+	}
+	return rc;
+}
+
 int main(int argc, char *argv[])
 {
 	struct mtest tss[] = {
 	{ "--match-fstype",  test_match_fstype,    "<type> <pattern>     FS types matching" },
 	{ "--match-options", test_match_options,   "<options> <pattern>  options matching" },
+	{ "--filesystems",   test_filesystems,	   "[<pattern>] list /{etc,proc}/filesystems" },
 	{ "--starts-with",   test_startswith,      "<string> <prefix>" },
 	{ "--ends-with",     test_endswith,        "<string> <prefix>" },
 	{ "--mountpoint",    test_mountpoint,      "<path>" },