4 files changed, 558 insertions, 3 deletions

diff --git a/shlibs/mount/src/Makefile.am b/shlibs/mount/src/Makefile.am
index f9cc68f93..598296316 100644
--- a/shlibs/mount/src/Makefile.am
+++ b/shlibs/mount/src/Makefile.am
@@ -11,7 +11,8 @@ nodist_mountinc_HEADERS = mount.h
 usrlib_exec_LTLIBRARIES = libmount.la
 libmount_la_SOURCES = $(mountinc_HEADERS)
 
-nodist_libmount_la_SOURCES = mount.h version.c utils.c test.c init.c
+nodist_libmount_la_SOURCES = mount.h version.c utils.c test.c init.c cache.c \
+			$(top_srcdir)/lib/canonicalize.c
 
 libmount_la_LIBADD = $(ul_libblkid_la)
 
@@ -20,7 +21,7 @@ libmount_la_DEPENDENCIES = $(libmount_la_LIBADD) mount.sym mount.h.in
 libmount_la_LDFLAGS = -Wl,--version-script=$(ul_libmount_srcdir)/mount.sym \
                       -version-info $(LIBMOUNT_VERSION_INFO)
 
-tests = test_version
+tests = test_version test_cache
 
 EXTRA_DIST = mount.sym mount.h.in
 CLEANFILES = $(tests)
diff --git a/shlibs/mount/src/cache.c b/shlibs/mount/src/cache.c
new file mode 100644
index 000000000..7b9040ff8
--- /dev/null
+++ b/shlibs/mount/src/cache.c
@@ -0,0 +1,533 @@
+/*
+ * Copyright (C) 2009 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <blkid.h>
+
+#include "canonicalize.h"
+#include "mountP.h"
+
+/*
+ * Canonicalized (resolved) paths cache
+ */
+#define MNT_CACHE_CHUNKSZ	128
+
+#define MNT_CACHE_ISTAG	(1 << 1) /* entry is TAG */
+#define MNT_CACHE_ISPATH	(1 << 2) /* entry is path */
+#define MNT_CACHE_TAGREAD	(1 << 3) /* tag read by mnt_cache_read_tags() */
+
+/* path cache entry */
+struct mnt_cache_entry {
+	char			*native;	/* the original path */
+	char			*real;		/* canonicalized path */
+	int			flag;
+};
+
+struct _mnt_cache {
+	struct mnt_cache_entry	*ents;
+	size_t			nents;
+	size_t			nallocs;
+
+	/* blkid_evaluate_tag() works in two ways:
+	 *
+	 * 1/ all tags are evaluated by udev /dev/disk/by-* symlinks,
+	 *    then the blkid_cache is NULL.
+	 *
+	 * 2/ all tags are read from /etc/blkid.tab and verified by /dev
+	 *    scanning, then the blkid_cache is not NULL and then it's
+	 *    better to reuse the blkid_cache.
+	 */
+	blkid_cache		bc;
+};
+
+/**
+ * mnt_new_cache:
+ *
+ * Returns new mnt_cache instance or NULL in case of ENOMEM error.
+ */
+mnt_cache *mnt_new_cache(void)
+{
+	return calloc(1, sizeof(struct _mnt_cache));
+}
+
+/**
+ * mnt_free_cache:
+ * @cache: pointer to mnt_cache instance
+ *
+ * Deallocates mnt_cache.
+ */
+void mnt_free_cache(mnt_cache *cache)
+{
+	int i;
+
+	if (!cache)
+		return;
+	for (i = 0; i < cache->nents; i++) {
+		struct mnt_cache_entry *e = &cache->ents[i];
+		if (e->real != e->native)
+			free(e->real);
+		free(e->native);
+	}
+	free(cache->ents);
+	if (cache->bc)
+		blkid_put_cache(cache->bc);
+	free(cache);
+}
+
+/* note that the @native could be tha same pointer as @real */
+static int mnt_cache_add_entry(mnt_cache *cache, char *native,
+					char *real, int flag)
+{
+	struct mnt_cache_entry *e;
+
+	assert(cache);
+	assert(real);
+	assert(native);
+
+	if (cache->nents == cache->nallocs) {
+		size_t sz = cache->nallocs + MNT_CACHE_CHUNKSZ;
+
+		e = realloc(cache->ents, sz * sizeof(struct mnt_cache_entry));
+		if (!e)
+			return -1;
+		cache->ents = e;
+		cache->nallocs = sz;
+	}
+
+	e = &cache->ents[cache->nents];
+	e->native = native;
+	e->real = real;
+	e->flag = flag;
+	cache->nents++;
+
+	DBG(DEBUG_CACHE,
+		printf("cache: [%zd entry] added %s\n", cache->nents, real));
+
+	return 0;
+}
+
+/* add tag to the cache, @real has to be allocated string */
+static int mnt_cache_add_tag(mnt_cache *cache, const char *token,
+				const char *value, char *real, int flag)
+{
+	size_t tksz, vlsz;
+	char *native;
+
+	assert(cache);
+	assert(real);
+	assert(token);
+	assert(value);
+
+	/* add into cache -- cache format for TAGs is
+	 *	native = "NAME\0VALUE\0"
+	 *	real   = "/dev/foo"
+	 */
+	tksz = strlen(token);
+	vlsz = strlen(value);
+
+	native = malloc(tksz + vlsz + 2);
+	if (!native)
+		goto error;
+
+	memcpy(native, token, tksz + 1);	   /* include '\0' */
+	memcpy(native + tksz + 1, value, vlsz + 1);
+
+	if (mnt_cache_add_entry(cache, native, real, flag))
+		goto error;
+	return 0;
+error:
+	free(native);
+	return -1;
+}
+
+
+/**
+ * mnt_cache_find_path:
+ * @cache: pointer to mnt_cache instance
+ * @path: requested "native" (non-canonicalized) path
+ *
+ * Returns cached canonicalized path or NULL.
+ */
+const char *mnt_cache_find_path(mnt_cache *cache, const char *path)
+{
+	int i;
+
+	assert(cache);
+	assert(path);
+
+	if (!cache || !path)
+		return NULL;
+
+	for (i = 0; i < cache->nents; i++) {
+		struct mnt_cache_entry *e = &cache->ents[i];
+		if (!(e->flag & MNT_CACHE_ISPATH))
+			continue;
+		if (strcmp(path, e->native) == 0)
+			return e->real;
+	}
+	return NULL;
+}
+
+/**
+ * mnt_cache_find_tag:
+ * @cache: pointer to mnt_cache instance
+ * @token: tag name
+ * @value: tag value
+ *
+ * Returns cached path or NULL.
+ */
+const char *mnt_cache_find_tag(mnt_cache *cache,
+			const char *token, const char *value)
+{
+	int i;
+	size_t tksz;
+
+	assert(cache);
+	assert(token);
+	assert(value);
+
+	if (!cache || !token || !value)
+		return NULL;
+
+	tksz = strlen(token);
+
+	for (i = 0; i < cache->nents; i++) {
+		struct mnt_cache_entry *e = &cache->ents[i];
+		if (!(e->flag & MNT_CACHE_ISTAG))
+			continue;
+		if (strcmp(token, e->native) == 0 &&
+		    strcmp(value, e->native + tksz + 1) == 0)
+			return e->real;
+	}
+	return NULL;
+}
+
+/**
+ * mnt_cache_read_tags
+ * @cache: pointer to mnt_cache instance
+ * @devname: path device
+ *
+ * Reads @devname LABEL and UUID to the @cache.
+ *
+ * Returns: 1 if at least on tag was added, 0 no tag was added or
+ *          -1 in case of error.
+ */
+int mnt_cache_read_tags(mnt_cache *cache, const char *devname)
+{
+	int i, ntags = 0;
+	int fd;
+	static blkid_probe pr;
+	const char *tags[] = { "LABEL", "UUID" };
+
+	assert(cache);
+	assert(devname);
+
+	if (!cache || !devname)
+		return -1;
+
+	/* check is device is already cached */
+	for (i = 0; i < cache->nents; i++) {
+		struct mnt_cache_entry *e = &cache->ents[i];
+		if (!(e->flag & MNT_CACHE_TAGREAD))
+			continue;
+		if (strcmp(e->real, devname) == 0)
+			/* tags has been already read */
+			return 0;
+	}
+
+	DBG(DEBUG_CACHE,
+		printf("cache: reading tags for: %s\n", devname));
+
+	fd = mnt_open_device(devname, O_RDONLY);
+	if (fd < 0)
+		return -1;
+	pr = blkid_new_probe();
+	if (!pr)
+		goto error;
+	if (blkid_probe_set_device(pr, fd, 0, 0))
+		goto error;
+
+	blkid_probe_enable_superblocks(pr, 1);
+
+	blkid_probe_set_superblocks_flags(pr,
+			BLKID_SUBLKS_LABEL | BLKID_SUBLKS_UUID);
+
+	if (blkid_do_safeprobe(pr))
+		goto error;
+
+	for (i = 0; i < ARRAY_SIZE(tags); i++) {
+		const char *data;
+		char *dev;
+
+		if (blkid_probe_lookup_value(pr, tags[i], &data, NULL))
+			continue;
+		if (mnt_cache_find_tag(cache, tags[i], data))
+			continue; /* already cached */
+
+		dev = strdup(devname);
+		if (!dev)
+			goto error;
+		if (mnt_cache_add_tag(cache, tags[i], data, dev,
+				(MNT_CACHE_ISTAG | MNT_CACHE_TAGREAD))) {
+			free(dev);
+			goto error;
+		}
+		ntags++;
+	}
+
+	return ntags ? 1 : 0;
+error:
+	blkid_free_probe(pr);
+	close(fd);
+	return -1;
+}
+
+/**
+ * mnt_cache_device_has_tag:
+ * @cache: paths cache
+ * @devname: path to the device
+ * @token: tag name (e.g "LABEL")
+ * @value: tag value
+ *
+ * Look up @cache to check it @tag+@value are associated with @devname.
+ *
+ * Returns: 1 on success or 0.
+ */
+int mnt_cache_device_has_tag(mnt_cache *cache, const char *devname,
+				const char *token, const char *value)
+{
+	const char *path = mnt_cache_find_tag(cache, token, value);
+
+	if (path && strcmp(path, devname) == 0)
+		return 1;
+	return 0;
+}
+
+/**
+ * mnt_resolve_path:
+ * @path: "native" path
+ * @cache: cache for results or NULL
+ *
+ * Returns absolute path or NULL in case of error. The result has to be
+ * deallocated by free() if @cache is NULL.
+ */
+char *mnt_resolve_path(const char *path, mnt_cache *cache)
+{
+	char *p = NULL;
+	char *native = NULL;
+	char *real = NULL;
+
+	assert(path);
+
+	if (!path)
+		return NULL;
+	if (cache)
+		p = (char *) mnt_cache_find_path(cache, path);
+
+	if (!p) {
+		p = canonicalize_path(path);
+
+		if (p && cache) {
+			native = strdup(path);
+			real = strcmp(path, p) == 0 ? native : p;
+
+			if (!native || !real)
+				goto error;
+
+			if (mnt_cache_add_entry(cache, native, real,
+							MNT_CACHE_ISPATH))
+				goto error;
+		}
+	}
+
+	DBG(DEBUG_CACHE, printf("cache: %s --> %s\n", path, p));
+	return p;
+error:
+	if (real != native)
+		free(real);
+	free(native);
+	return NULL;
+}
+
+/**
+ * mnt_resolve_tag:
+ * @token: tag name
+ * @value: tag value
+ * @cache: for results or NULL
+ *
+ * Returns device name or NULL in case of error. The result has to be
+ * deallocated by free() if @cache is NULL.
+ */
+char *mnt_resolve_tag(const char *token, const char *value, mnt_cache *cache)
+{
+	char *p = NULL;
+
+	assert(token);
+	assert(value);
+
+	if (!token || !value)
+		return NULL;
+
+	if (cache)
+		p = (char *) mnt_cache_find_tag(cache, token, value);
+
+	if (!p) {
+		/* returns newly allocated string */
+		p = blkid_evaluate_tag(token, value, cache ? &cache->bc : NULL);
+
+		if (p && cache &&
+		    mnt_cache_add_tag(cache, token, value, p, MNT_CACHE_ISTAG))
+				goto error;
+	}
+
+	DBG(DEBUG_CACHE, printf("cache: %s=%s --> %s\n", token, value, p));
+	return p;
+error:
+	free(p);
+	return NULL;
+}
+
+
+
+/**
+ * mnt_resolve_spec:
+ * @spec: path or tag
+ * @cache: paths cache
+ *
+ * Returns canonicalized path or NULL.
+ */
+char *mnt_resolve_spec(const char *spec, mnt_cache *cache)
+{
+	char *cn = NULL;
+
+	if (!spec)
+		return NULL;
+
+	if (strchr(spec, '=')) {
+		char *tag, *val;
+
+		if (!blkid_parse_tag_string(spec, &tag, &val)) {
+			cn = mnt_resolve_tag(tag, val, cache);
+
+			free(tag);
+			free(val);
+		}
+	} else
+		cn = mnt_resolve_path(spec, cache);
+
+	return cn;
+}
+
+
+#ifdef TEST_PROGRAM
+
+int test_resolve_path(struct mtest *ts, int argc, char *argv[])
+{
+	char line[BUFSIZ];
+	mnt_cache *cache;
+
+	cache = mnt_new_cache();
+	if (!cache)
+		return -1;
+
+	while(fgets(line, sizeof(line), stdin)) {
+		size_t sz = strlen(line);
+		char *p;
+
+		if (line[sz - 1] == '\n')
+			line[sz - 1] = '\0';
+
+		p = mnt_resolve_path(line, cache);
+		printf("%s : %s\n", line, p);
+	}
+	mnt_free_cache(cache);
+	return 0;
+}
+
+int test_resolve_spec(struct mtest *ts, int argc, char *argv[])
+{
+	char line[BUFSIZ];
+	mnt_cache *cache;
+
+	cache = mnt_new_cache();
+	if (!cache)
+		return -1;
+
+	while(fgets(line, sizeof(line), stdin)) {
+		size_t sz = strlen(line);
+		char *p;
+
+		if (line[sz - 1] == '\n')
+			line[sz - 1] = '\0';
+
+		p = mnt_resolve_spec(line, cache);
+		printf("%s : %s\n", line, p);
+	}
+	mnt_free_cache(cache);
+	return 0;
+}
+
+int test_read_tags(struct mtest *ts, int argc, char *argv[])
+{
+	char line[BUFSIZ];
+	mnt_cache *cache;
+
+	cache = mnt_new_cache();
+	if (!cache)
+		return -1;
+
+	while(fgets(line, sizeof(line), stdin)) {
+		size_t sz = strlen(line);
+
+		if (line[sz - 1] == '\n')
+			line[sz - 1] = '\0';
+
+		if (*line == '/') {
+			if (mnt_cache_read_tags(cache, line) < 0)
+				fprintf(stderr, "%s: read tags faild\n", line);
+
+		} else if (strchr(line, '=')) {
+			char *tag, *val;
+			const char *cn = NULL;
+
+			if (!blkid_parse_tag_string(line, &tag, &val)) {
+				cn = mnt_cache_find_tag(cache, tag, val);
+
+				free(tag);
+				free(val);
+			}
+			if (cn)
+				printf("%s: %s\n", line, cn);
+			else
+				printf("%s: not cached\n", line);
+		}
+	}
+	mnt_free_cache(cache);
+	return 0;
+
+}
+
+int main(int argc, char *argv[])
+{
+	struct mtest ts[] = {
+		{ "--resolve-path", test_resolve_path, "  resolve paths from stdin" },
+		{ "--resolve-spec", test_resolve_spec, "  evaluate specs from stdin" },
+		{ "--read-tags", test_read_tags,       "  read devname or TAG stdin" },
+		{ NULL }
+	};
+
+	return mnt_run_test(ts, argc, argv);
+}
+#endif
diff --git a/shlibs/mount/src/mount.h.in b/shlibs/mount/src/mount.h.in
index 6990e5ceb..e0f95807e 100644
--- a/shlibs/mount/src/mount.h.in
+++ b/shlibs/mount/src/mount.h.in
@@ -27,6 +27,13 @@ extern "C" {
 
 #define LIBMOUNT_VERSION   "@LIBMOUNT_VERSION@"
 
+/**
+ * mnt_cache
+ *
+ * Stores canonicalized paths and evaluated tags
+ */
+typedef struct _mnt_cache mnt_cache;
+
 /* version.c */
 extern int mnt_parse_version_string(const char *ver_string);
 extern int mnt_get_library_version(const char **ver_string);
@@ -36,6 +43,19 @@ extern int mnt_fstype_is_netfs(const char *type);
 extern int mnt_fstype_is_pseudofs(const char *type);
 extern int mnt_open_device(const char *devname, int flags);
 
+/* cache.c */
+extern mnt_cache *mnt_new_cache(void);
+extern void mnt_free_cache(mnt_cache *cache);
+extern const char *mnt_cache_find_path(mnt_cache *cache, const char *path);
+extern const char *mnt_cache_find_tag(mnt_cache *cache,
+                        const char *token, const char *value);
+extern int mnt_cache_read_tags(mnt_cache *cache, const char *devname);
+extern int mnt_cache_device_has_tag(mnt_cache *cache, const char *devname,
+                                const char *token, const char *value);
+extern char *mnt_resolve_path(const char *path, mnt_cache *cache);
+extern char *mnt_resolve_tag(const char *token, const char *value, mnt_cache *cache);
+extern char *mnt_resolve_spec(const char *spec, mnt_cache *cache);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/shlibs/mount/src/mountP.h b/shlibs/mount/src/mountP.h
index 5ac3b6bc0..21f3e67ed 100644
--- a/shlibs/mount/src/mountP.h
+++ b/shlibs/mount/src/mountP.h
@@ -30,13 +30,14 @@
 #endif
 
 #define DEBUG_INIT	(1 << 1)
+#define DEBUG_CACHE	(1 << 2)
 #define DEBUG_ALL	0xFFFF
 
 #ifdef CONFIG_LIBMOUNT_DEBUG
 #include <stdio.h>
 extern int libmount_debug_mask;
 extern void mnt_init_debug(int mask);
-#define DBG(m,x)	if ((m) & libmount_debug_mask) x;
+#define DBG(m,x)	if ((m) & libmount_debug_mask) x
 #else
 #define DBG(m,x)
 #define mnt_init_debug(x)