build-sys: use top-level directory for libmount rather than shlibs/mount

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

1 files changed, 667 insertions, 0 deletions

diff --git a/libmount/src/cache.c b/libmount/src/cache.c
new file mode 100644
index 000000000..4775069c0
--- /dev/null
+++ b/libmount/src/cache.c
@@ -0,0 +1,667 @@
+/*
+ * Copyright (C) 2009 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+
+/**
+ * SECTION: cache
+ * @title: Cache
+ * @short_description: paths and tags (UUID/LABEL) caching
+ *
+ * The cache is a very simple API for work with tags (LABEL, UUID, ...) and
+ * paths. The cache uses libblkid as a backend from TAGs resolution.
+ *
+ * All returned paths are always canonicalized.
+ */
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <limits.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 & tags 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 libmnt_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;
+	blkid_probe		pr;
+
+	char			*filename;
+};
+
+/**
+ * mnt_new_cache:
+ *
+ * Returns: new struct libmnt_cache instance or NULL in case of ENOMEM error.
+ */
+struct libmnt_cache *mnt_new_cache(void)
+{
+	struct libmnt_cache *cache = calloc(1, sizeof(*cache));
+	if (!cache)
+		return NULL;
+	DBG(CACHE, mnt_debug_h(cache, "alloc"));
+	return cache;
+}
+
+/**
+ * mnt_free_cache:
+ * @cache: pointer to struct libmnt_cache instance
+ *
+ * Deallocates the cache.
+ */
+void mnt_free_cache(struct libmnt_cache *cache)
+{
+	int i;
+
+	if (!cache)
+		return;
+
+	DBG(CACHE, mnt_debug_h(cache, "free"));
+
+	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);
+	free(cache->filename);
+	if (cache->bc)
+		blkid_put_cache(cache->bc);
+	blkid_free_probe(cache->pr);
+	free(cache);
+}
+
+/* note that the @native could be tha same pointer as @real */
+static int mnt_cache_add_entry(struct libmnt_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 -ENOMEM;
+		cache->ents = e;
+		cache->nallocs = sz;
+	}
+
+	e = &cache->ents[cache->nents];
+	e->native = native;
+	e->real = real;
+	e->flag = flag;
+	cache->nents++;
+
+	DBG(CACHE, mnt_debug_h(cache, "add entry [%2zd] (%s): %s: %s",
+			cache->nents,
+			(flag & MNT_CACHE_ISPATH) ? "path" : "tag",
+			real, native));
+	return 0;
+}
+
+/* add tag to the cache, @real has to be allocated string */
+static int mnt_cache_add_tag(struct libmnt_cache *cache, const char *token,
+				const char *value, char *real, int flag)
+{
+	size_t tksz, vlsz;
+	char *native;
+	int rc;
+
+	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)
+		return -ENOMEM;
+
+	memcpy(native, token, tksz + 1);	   /* include '\0' */
+	memcpy(native + tksz + 1, value, vlsz + 1);
+
+	rc = mnt_cache_add_entry(cache, native, real, flag | MNT_CACHE_ISTAG);
+	if (!rc)
+		return 0;
+
+	free(native);
+	return rc;
+}
+
+
+/*
+ * Returns cached canonicalized path or NULL.
+ */
+static const char *mnt_cache_find_path(struct libmnt_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;
+}
+
+/*
+ * Returns cached path or NULL.
+ */
+static const char *mnt_cache_find_tag(struct libmnt_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;
+}
+
+/*
+ * returns (in @res) blkid prober, the @cache argument is optional
+ */
+static int mnt_cache_get_probe(struct libmnt_cache *cache, const char *devname,
+			   blkid_probe *res)
+{
+	blkid_probe pr = cache ? cache->pr : NULL;
+
+	assert(devname);
+	assert(res);
+
+	if (cache && cache->pr && (!cache->filename ||
+				   strcmp(devname, cache->filename))) {
+		blkid_free_probe(cache->pr);
+		free(cache->filename);
+		cache->filename = NULL;
+		pr = cache->pr = NULL;
+	}
+
+	if (!pr) {
+		pr = blkid_new_probe_from_filename(devname);
+		if (!pr)
+			return -1;
+		if (cache) {
+			cache->pr = pr;
+			cache->filename = strdup(devname);
+			if (!cache->filename)
+				return -ENOMEM;
+		}
+
+	}
+
+	*res = pr;
+	return 0;
+}
+
+/**
+ * mnt_cache_read_tags
+ * @cache: pointer to struct libmnt_cache instance
+ * @devname: path device
+ *
+ * Reads @devname LABEL and UUID to the @cache.
+ *
+ * Returns: 0 if at least one tag was added, 1 if no tag was added or
+ *          negative number in case of error.
+ */
+int mnt_cache_read_tags(struct libmnt_cache *cache, const char *devname)
+{
+	int i, ntags = 0, rc;
+	blkid_probe pr;
+	const char *tags[] = { "LABEL", "UUID", "TYPE" };
+
+	assert(cache);
+	assert(devname);
+
+	if (!cache || !devname)
+		return -EINVAL;
+
+	DBG(CACHE, mnt_debug_h(cache, "tags for %s requested", devname));
+
+	/* 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;
+	}
+
+	rc = mnt_cache_get_probe(cache, devname, &pr);
+	if (rc)
+		return rc;
+
+	blkid_probe_enable_superblocks(cache->pr, 1);
+
+	blkid_probe_set_superblocks_flags(cache->pr,
+			BLKID_SUBLKS_LABEL | BLKID_SUBLKS_UUID |
+			BLKID_SUBLKS_TYPE);
+
+	if (blkid_do_safeprobe(cache->pr))
+		goto error;
+
+	DBG(CACHE, mnt_debug_h(cache, "reading tags for: %s", devname));
+
+	for (i = 0; i < ARRAY_SIZE(tags); i++) {
+		const char *data;
+		char *dev;
+
+		if (blkid_probe_lookup_value(cache->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_TAGREAD)) {
+			free(dev);
+			goto error;
+		}
+		ntags++;
+	}
+
+	return ntags ? 0 : 1;
+error:
+	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(struct libmnt_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_cache_find_tag_value:
+ * @cache: cache for results
+ * @devname: device name
+ * @token: tag name ("LABEL" or "UUID")
+ *
+ * Returns: LABEL or UUID for the @devname or NULL in case of error.
+ */
+char *mnt_cache_find_tag_value(struct libmnt_cache *cache,
+		const char *devname, const char *token)
+{
+	int i;
+
+	if (!cache || !devname || !token)
+		return NULL;
+
+	if (mnt_cache_read_tags(cache, devname) != 0)
+		return NULL;
+
+	for (i = 0; i < cache->nents; i++) {
+		struct mnt_cache_entry *e = &cache->ents[i];
+		if (!(e->flag & MNT_CACHE_ISTAG))
+			continue;
+		if (strcmp(e->real, devname) == 0 &&	/* dev name */
+		    strcmp(token, e->native) == 0)	/* tag name */
+			return e->native + strlen(token) + 1;	/* tag value */
+	}
+
+	return NULL;
+}
+
+/**
+ * mnt_get_fstype:
+ * @devname: device name
+ * @ambi: returns TRUE if probing result is ambivalent (optional argument)
+ * @cache: cache for results or NULL
+ *
+ * Returns: filesystem type or NULL in case of error. The result has to be
+ * deallocated by free() if @cache is NULL.
+ */
+char *mnt_get_fstype(const char *devname, int *ambi, struct libmnt_cache *cache)
+{
+	blkid_probe pr;
+	const char *data;
+	char *type = NULL;
+	int rc;
+
+	DBG(CACHE, mnt_debug_h(cache, "get %s FS type", devname));
+
+	if (cache)
+		return mnt_cache_find_tag_value(cache, devname, "TYPE");
+
+	if (mnt_cache_get_probe(NULL, devname, &pr))
+		return NULL;
+
+	blkid_probe_enable_superblocks(pr, 1);
+
+	blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_TYPE);
+
+	rc = blkid_do_safeprobe(pr);
+
+	if (!rc && !blkid_probe_lookup_value(pr, "TYPE", &data, NULL))
+		type = strdup(data);
+
+	if (ambi)
+		*ambi = rc == -2 ? TRUE : FALSE;
+
+	blkid_free_probe(pr);
+	return type;
+}
+
+/**
+ * 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, struct libmnt_cache *cache)
+{
+	char *p = NULL;
+	char *native = NULL;
+	char *real = NULL;
+
+	assert(path);
+
+	/*DBG(CACHE, mnt_debug_h(cache, "resolving path %s", path));*/
+
+	if (!path)
+		return NULL;
+	if (cache)
+		p = (char *) mnt_cache_find_path(cache, path);
+
+	if (!p) {
+		p = canonicalize_path(path);
+
+		if (p && cache) {
+			real = p;
+			native = strcmp(path, p) == 0 ? real : strdup(path);
+
+			if (!native || !real)
+				goto error;
+
+			if (mnt_cache_add_entry(cache, native, real,
+							MNT_CACHE_ISPATH))
+				goto error;
+		}
+	}
+
+	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,
+		      struct libmnt_cache *cache)
+{
+	char *p = NULL;
+
+	assert(token);
+	assert(value);
+
+	/*DBG(CACHE, mnt_debug_h(cache, "resolving tag token=%s value=%s",
+				token, 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, 0))
+				goto error;
+	}
+
+	return p;
+error:
+	free(p);
+	return NULL;
+}
+
+
+
+/**
+ * mnt_resolve_spec:
+ * @spec: path or tag
+ * @cache: paths cache
+ *
+ * Returns: canonicalized path or NULL. The result has to be
+ * deallocated by free() if @cache is NULL.
+ */
+char *mnt_resolve_spec(const char *spec, struct libmnt_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 libmnt_test *ts, int argc, char *argv[])
+{
+	char line[BUFSIZ];
+	struct libmnt_cache *cache;
+
+	cache = mnt_new_cache();
+	if (!cache)
+		return -ENOMEM;
+
+	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 libmnt_test *ts, int argc, char *argv[])
+{
+	char line[BUFSIZ];
+	struct libmnt_cache *cache;
+
+	cache = mnt_new_cache();
+	if (!cache)
+		return -ENOMEM;
+
+	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 libmnt_test *ts, int argc, char *argv[])
+{
+	char line[BUFSIZ];
+	struct libmnt_cache *cache;
+	int i;
+
+	cache = mnt_new_cache();
+	if (!cache)
+		return -ENOMEM;
+
+	while(fgets(line, sizeof(line), stdin)) {
+		size_t sz = strlen(line);
+
+		if (line[sz - 1] == '\n')
+			line[sz - 1] = '\0';
+
+		if (!strcmp(line, "quit"))
+			break;
+
+		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);
+		}
+	}
+
+	for (i = 0; i < cache->nents; i++) {
+		struct mnt_cache_entry *e = &cache->ents[i];
+		if (!(e->flag & MNT_CACHE_ISTAG))
+			continue;
+
+		printf("%15s : %5s : %s\n", e->real, e->native,
+				e->native + strlen(e->native) + 1);
+	}
+
+	mnt_free_cache(cache);
+	return 0;
+
+}
+
+int main(int argc, char *argv[])
+{
+	struct libmnt_test 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 from stdin (\"quit\" to exit)" },
+		{ NULL }
+	};
+
+	return mnt_run_test(ts, argc, argv);
+}
+#endif