libmount: allows to swap source and target

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

3 files changed, 149 insertions, 164 deletions

diff --git a/shlibs/mount/src/context.c b/shlibs/mount/src/context.c
index 07a72c2d3..1d3c76a75 100644
--- a/shlibs/mount/src/context.c
+++ b/shlibs/mount/src/context.c
@@ -57,7 +57,6 @@ void mnt_free_context(mnt_context *cxt)
 
 	free(cxt->fstype_pattern);
 	free(cxt->optstr_pattern);
-	free(cxt->spec);
 	free(cxt->helper);
 	free(cxt->orig_user);
 
@@ -113,11 +112,9 @@ int mnt_reset_context(mnt_context *cxt)
 	cxt->fs = NULL;
 	cxt->mtab = NULL;
 
-	free(cxt->spec);
 	free(cxt->helper);
 	free(cxt->orig_user);
 
-	cxt->spec = NULL;
 	cxt->helper = NULL;
 
 	cxt->mountflags = 0;
@@ -333,27 +330,6 @@ int mnt_context_enable_loopdel(mnt_context *cxt, int enable)
 }
 
 /**
- * mnt_context_set_spec:
- * @cxt: mount context
- * @spec: unresolved source (device, label, uuid, ...) or target (mountpoint)
- *
- * Returns: 0 on success, negative number in case of error.
- */
-int mnt_context_set_spec(mnt_context *cxt, const char *spec)
-{
-	char *p;
-
-	if (!cxt)
-		return -EINVAL;
-	p = strdup(spec);
-	if (!p)
-		return -ENOMEM;
-	free(cxt->spec);
-	cxt->spec = p;
-	return 0;
-}
-
-/**
  * mnt_context_set_fs:
  * @cxt: mount context
  * @fs: filesystem description
@@ -960,3 +936,147 @@ int mnt_context_prepare_update(mnt_context *cxt, int act)
 	return rc;
 }
 
+static int is_remount(mnt_context *cxt)
+{
+	unsigned long fl = 0;
+
+	if (cxt->mountflags & MS_REMOUNT)
+		return 1;
+	if (!mnt_context_get_mountflags(cxt, &fl) && (fl & MS_REMOUNT))
+		return 1;
+	return 0;
+}
+
+static int apply_tab(mnt_context *cxt, mnt_tab *tb)
+{
+	mnt_fs *fs = NULL;
+	const char *src = NULL, *tgt = NULL;
+	int rc;
+
+	if (!cxt->fs)
+		return -EINVAL;
+
+	src = mnt_fs_get_source(cxt->fs);
+	tgt = mnt_fs_get_target(cxt->fs);
+
+	if (tgt && src)
+		;	/* TODO: search pair for MNT_OPTSMODE_FORCE */
+	else {
+		if (src)
+			fs = mnt_tab_find_source(tb, src, MNT_ITER_FORWARD);
+		else if (tgt)
+			fs = mnt_tab_find_target(tb, tgt, MNT_ITER_FORWARD);
+
+		if (!fs) {
+			/* swap source and target (if @src is not LABEL/UUID),
+			 * for example in
+			 *
+			 *	mount /foo/bar
+			 *
+			 * the path could be a mountpoint as well as source (for
+			 * example bind mount, symlink to device, ...).
+			 */
+			if (src && !mnt_fs_get_tag(cxt->fs, NULL, NULL))
+				fs = mnt_tab_find_target(tb, src,
+							MNT_ITER_FORWARD);
+			if (!fs && tgt)
+				fs = mnt_tab_find_source(tb, tgt,
+							MNT_ITER_FORWARD);
+		}
+	}
+
+	if (!fs)
+		return -EINVAL;
+
+	DBG(CXT, mnt_debug_h(cxt, "apply entry:"));
+	DBG(CXT, mnt_fs_print_debug(fs, stderr));
+
+	/* copy from fstab to our FS description
+	 */
+	rc = mnt_fs_set_source(cxt->fs, mnt_fs_get_source(fs));
+	if (!rc)
+		rc = mnt_fs_set_target(cxt->fs, mnt_fs_get_target(fs));
+
+	if (!rc && !mnt_fs_get_fstype(cxt->fs))
+		rc = mnt_fs_set_fstype(cxt->fs, mnt_fs_get_fstype(fs));
+
+	if (!rc && cxt->optsmode != MNT_OPTSMODE_IGNORE)
+		rc = mnt_fs_prepend_optstr(cxt->fs, mnt_fs_get_optstr(fs));
+
+	if (!rc)
+		cxt->flags |= MNT_FL_FSTAB_APPLIED;
+
+	return rc;
+}
+
+int mnt_context_apply_fstab(mnt_context *cxt)
+{
+	int rc;
+	mnt_cache *cache;
+	const char *src = NULL, *tgt = NULL;
+
+	if (!cxt || !cxt->fs)
+		return -EINVAL;
+
+	if (cxt->flags & MNT_FL_FSTAB_APPLIED)
+		return 0;
+
+	if (cxt->fs) {
+		src = mnt_fs_get_source(cxt->fs);
+		tgt = mnt_fs_get_target(cxt->fs);
+	}
+
+	/* fstab is not required if source and target are specified */
+	if (src && tgt && !(cxt->optsmode == MNT_OPTSMODE_FORCE ||
+			    cxt->optsmode == MNT_OPTSMODE_MTABFORCE))
+		return 0;
+
+	DBG(CXT, mnt_debug_h(cxt,
+		"trying to apply fstab (src=%s, target=%s)", src, tgt));
+
+	/* initialize fstab */
+	if (!cxt->fstab) {
+		cxt->fstab = mnt_new_tab();
+		if (!cxt->fstab)
+			goto errnomem;
+		cxt->flags &= ~MNT_FL_EXTERN_FSTAB;
+		rc = mnt_tab_parse_fstab(cxt->fstab);
+		if (rc)
+			goto err;
+	}
+
+	cache = mnt_context_get_cache(cxt);	/* NULL if MNT_FL_NOCANONICALIZE is enabled */
+
+	/*  never touch an external fstab */
+	if (!(cxt->flags & MNT_FL_EXTERN_FSTAB))
+		mnt_tab_set_cache(cxt->fstab, cache);
+
+	/* let's initialize cxt->fs */
+	mnt_context_get_fs(cxt);
+
+	/* try fstab */
+	rc = apply_tab(cxt, cxt->fstab);
+
+	/* try mtab */
+	if (rc || (cxt->optsmode == MNT_OPTSMODE_MTABFORCE && is_remount(cxt))) {
+
+		cxt->mtab = mnt_new_tab();
+		if (!cxt->mtab)
+			goto errnomem;
+		rc = mnt_tab_parse_mtab(cxt->mtab);
+		if (rc)
+			goto err;
+
+		mnt_tab_set_cache(cxt->mtab, cache);
+		rc = apply_tab(cxt, cxt->mtab);
+		if (rc)
+			goto err;
+	}
+	return 0;
+
+errnomem:
+	rc = ENOMEM;
+err:
+	DBG(CXT, mnt_debug_h(cxt, "failed to found entry in fstab/mtab"));
+	return rc;
+}
diff --git a/shlibs/mount/src/context_mount.c b/shlibs/mount/src/context_mount.c
index d5f361a83..77f9497da 100644
--- a/shlibs/mount/src/context_mount.c
+++ b/shlibs/mount/src/context_mount.c
@@ -24,140 +24,6 @@
 #include "c.h"
 #include "mountP.h"
 
-static int is_remount(mnt_context *cxt)
-{
-	unsigned long fl = 0;
-
-	if (cxt->mountflags & MS_REMOUNT)
-		return 1;
-	if (!mnt_context_get_mountflags(cxt, &fl) && (fl & MS_REMOUNT))
-		return 1;
-	return 0;
-}
-
-static int apply_tab(mnt_context *cxt, mnt_tab *tb)
-{
-	mnt_fs *fs = NULL;
-	const char *src = NULL, *tgt = NULL;
-	int rc;
-
-	if (!cxt->fs)
-		return -EINVAL;
-
-	src = mnt_fs_get_source(cxt->fs);
-	tgt = mnt_fs_get_target(cxt->fs);
-
-	if (tgt && src)
-		;	/* TODO: search pair for MNT_OPTSMODE_FORCE */
-	else if (src)
-		fs = mnt_tab_find_source(tb, src, MNT_ITER_FORWARD);
-	else if (tgt)
-		fs = mnt_tab_find_target(tb, tgt, MNT_ITER_FORWARD);
-	else if (cxt->spec) {
-		fs = mnt_tab_find_source(tb, cxt->spec, MNT_ITER_FORWARD);
-
-		if (!fs && (strncmp(cxt->spec, "LABEL=", 6) ||
-			    strncmp(cxt->spec, "UUID=", 5)))
-			fs = mnt_tab_find_target(tb, cxt->spec, MNT_ITER_FORWARD);
-	}
-
-	if (!fs)
-		return -EINVAL;
-
-	DBG(CXT, mnt_debug_h(cxt, "apply entry:"));
-	DBG(CXT, mnt_fs_print_debug(fs, stderr));
-
-	/* copy from fstab to our FS description
-	 */
-	rc = mnt_fs_set_source(cxt->fs, mnt_fs_get_source(fs));
-	if (!rc)
-		rc = mnt_fs_set_target(cxt->fs, mnt_fs_get_target(fs));
-
-	if (!rc && !mnt_fs_get_fstype(cxt->fs))
-		rc = mnt_fs_set_fstype(cxt->fs, mnt_fs_get_fstype(fs));
-
-	if (!rc && cxt->optsmode != MNT_OPTSMODE_IGNORE)
-		rc = mnt_fs_prepend_optstr(cxt->fs, mnt_fs_get_optstr(fs));
-
-	if (!rc)
-		cxt->flags |= MNT_FL_FSTAB_APPLIED;
-
-	return rc;
-}
-
-static int apply_fstab(mnt_context *cxt)
-{
-	int rc;
-	mnt_cache *cache;
-	const char *src = NULL, *tgt = NULL;
-
-	if (!cxt || (!cxt->spec && !cxt->fs))
-		return -EINVAL;
-
-	if (cxt->flags & MNT_FL_FSTAB_APPLIED)
-		return 0;
-
-	if (cxt->fs) {
-		src = mnt_fs_get_source(cxt->fs);
-		tgt = mnt_fs_get_target(cxt->fs);
-	}
-
-	/* fstab is not required if source and target are specified */
-	if (src && tgt && !(cxt->optsmode == MNT_OPTSMODE_FORCE ||
-			    cxt->optsmode == MNT_OPTSMODE_MTABFORCE))
-		return 0;
-
-	DBG(CXT, mnt_debug_h(cxt,
-		"trying to apply fstab (src=%s, target=%s, spec=%s)",
-		src, tgt, cxt->spec));
-
-	/* initialize fstab */
-	if (!cxt->fstab) {
-		cxt->fstab = mnt_new_tab();
-		if (!cxt->fstab)
-			goto errnomem;
-		cxt->flags &= ~MNT_FL_EXTERN_FSTAB;
-		rc = mnt_tab_parse_fstab(cxt->fstab);
-		if (rc)
-			goto err;
-	}
-
-	cache = mnt_context_get_cache(cxt);	/* NULL if MNT_FL_NOCANONICALIZE is enabled */
-
-	/*  never touch an external fstab */
-	if (!(cxt->flags & MNT_FL_EXTERN_FSTAB))
-		mnt_tab_set_cache(cxt->fstab, cache);
-
-	/* let's initialize cxt->fs */
-	mnt_context_get_fs(cxt);
-
-	/* try fstab */
-	rc = apply_tab(cxt, cxt->fstab);
-
-	/* try mtab */
-	if (rc || (cxt->optsmode == MNT_OPTSMODE_MTABFORCE && is_remount(cxt))) {
-
-		cxt->mtab = mnt_new_tab();
-		if (!cxt->mtab)
-			goto errnomem;
-		rc = mnt_tab_parse_mtab(cxt->mtab);
-		if (rc)
-			goto err;
-
-		mnt_tab_set_cache(cxt->mtab, cache);
-		rc = apply_tab(cxt, cxt->mtab);
-		if (rc)
-			goto err;
-	}
-	return 0;
-
-errnomem:
-	rc = ENOMEM;
-err:
-	DBG(CXT, mnt_debug_h(cxt, "failed to found entry in fstab/mtab"));
-	return rc;
-}
-
 /*
  * this has to be called after mnt_context_evaluate_permissions()
  */
@@ -526,11 +392,11 @@ int mnt_context_prepare_mount(mnt_context *cxt)
 	if (!cxt)
 		return -EINVAL;
 
-	if (!cxt->spec && !(cxt->fs && (mnt_fs_get_source(cxt->fs) ||
-			                mnt_fs_get_target(cxt->fs))))
+	if (!cxt->fs || (!mnt_fs_get_source(cxt->fs) &&
+			 !mnt_fs_get_target(cxt->fs)))
 		return -EINVAL;
 
-	rc = apply_fstab(cxt);
+	rc = mnt_context_apply_fstab(cxt);
 	if (!rc)
 		rc = merge_mountflags(cxt);
 	if (!rc)
@@ -671,8 +537,8 @@ int test_mount(struct mtest *ts, int argc, char *argv[])
 	}
 
 	if (argc == idx + 1)
-		/* mount <spec> */
-		mnt_context_set_spec(cxt, argv[idx++]);
+		/* mount <mountpont>|<device> */
+		mnt_context_set_target(cxt, argv[idx++]);
 
 	else if (argc == idx + 2) {
 		/* mount <device> <mountpoint> */
diff --git a/shlibs/mount/src/mountP.h b/shlibs/mount/src/mountP.h
index 51230c67b..fba072e31 100644
--- a/shlibs/mount/src/mountP.h
+++ b/shlibs/mount/src/mountP.h
@@ -214,7 +214,6 @@ struct _mnt_context
 	char	*fstype_pattern;	/* for mnt_match_fstype() */
 	char	*optstr_pattern;	/* for mnt_match_options() */
 
-	char	*spec;		/* unresolved source OR target */
 	mnt_fs	*fs;		/* filesystem description (type, mountpopint, device, ...) */
 
 	mnt_tab	*fstab;		/* fstab (or mtab for some remounts) entires */