/*
* Copyright (C) 2008 Karel Zak <kzak@redhat.com>
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*
* Note:
* mnt_tab_find_* functions are mount(8) compatible. It means it tries
* to found an entry in more iterations where the first attempt is always
* based on comparison with unmodified (non-canonicalized or un-evaluated)
* paths or tags. For example fstab with two entries:
*
* LABEL=foo /foo auto rw
* /dev/foo /foo auto rw
*
* where both lines are used for the *same* device, then
*
* mnt_tab_find_source(tb, "/dev/foo", &fs);
*
* will returns the second line, and
*
* mnt_tab_find_source(tb, "LABEL=foo", &fs);
*
* will returns the first entry, and
*
* mnt_tab_find_source(tb, "UUID=<anyuuid>", &fs);
*
* will returns the first entry (if UUID matches with the device).
*/
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <blkid/blkid.h>
#include "nls.h"
#include "mountP.h"
/**
* mnt_new_tab:
* @filename: file name or NULL
*
* The tab is a container for mnt_fs entries that usually represents a fstab,
* mtab or mountinfo file from your system.
*
* Note that this function does not parse the file. See also
* mnt_tab_parse_file().
*
* Returns newly allocated tab struct.
*/
mnt_tab *mnt_new_tab(const char *filename)
{
mnt_tab *tb = NULL;
tb = calloc(1, sizeof(struct _mnt_tab));
if (!tb)
goto err;
if (filename) {
tb->filename = strdup(filename);
if (!tb->filename)
goto err;
}
INIT_LIST_HEAD(&tb->ents);
return tb;
err:
free(tb);
return NULL;
}
/**
* mnt_free_tab:
* @tab: tab pointer
*
* Deallocates tab struct and all entries.
*/
void mnt_free_tab(mnt_tab *tb)
{
if (!tb)
return;
free(tb->filename);
while (!list_empty(&tb->ents)) {
mnt_fs *fs = list_entry(tb->ents.next, mnt_fs, ents);
mnt_free_fs(fs);
}
free(tb);
}
/**
* mnt_tab_get_nents:
* @tb: pointer to tab
*
* Returns number of valid entries in tab.
*/
int mnt_tab_get_nents(mnt_tab *tb)
{
assert(tb);
return tb ? tb->nents : 0;
}
/**
* mnt_tab_set_cache:
* @tb: pointer to tab
* @mpc: pointer to mnt_cache instance
*
* Setups a cache for canonicalized paths and evaluated tags (LABEL/UUID). The
* cache is recommended for mnt_tab_find_*() functions.
*
* The cache could be shared between more tabs. Be careful when you share the
* same cache between more threads -- currently the cache does not provide any
* locking method.
*
* See also mnt_new_cache().
*
* Returns 0 on success or -1 in case of error.
*/
int mnt_tab_set_cache(mnt_tab *tb, mnt_cache *mpc)
{
assert(tb);
if (!tb)
return -1;
tb->cache = mpc;
return 0;
}
/**
* mnt_tab_get_cache:
* @tb: pointer to tab
*
* Returns pointer to mnt_cache instance or NULL.
*/
mnt_cache *mnt_tab_get_cache(mnt_tab *tb)
{
assert(tb);
return tb ? tb->cache : NULL;
}
/**
* mnt_tab_get_name:
* @tb: tab pointer
*
* Returns tab filename or NULL.
*/
const char *mnt_tab_get_name(mnt_tab *tb)
{
assert(tb);
return tb ? tb->filename : NULL;
}
/**
* mnt_tab_add_fs:
* @tb: tab pointer
* @fs: new entry
*
* Adds a new entry to tab.
*
* Returns 0 on success or -1 in case of error.
*/
int mnt_tab_add_fs(mnt_tab *tb, mnt_fs *fs)
{
assert(tb);
assert(fs);
if (!tb || !fs)
return -1;
list_add_tail(&fs->ents, &tb->ents);
DBG(DEBUG_TAB, fprintf(stderr,
"libmount: %s: add entry: %s %s\n",
tb->filename, mnt_fs_get_source(fs),
mnt_fs_get_target(fs)));
if (fs->flags & MNT_FS_ERROR)
tb->nerrs++;
else
tb->nents++;
return 0;
}
/**
* mnt_tab_remove_fs:
* @tb: tab pointer
* @fs: new entry
*
* Returns 0 on success or -1 in case of error.
*/
int mnt_tab_remove_fs(mnt_tab *tb, mnt_fs *fs)
{
assert(tb);
assert(fs);
if (!tb || !fs)
return -1;
list_del(&fs->ents);
if (fs->flags & MNT_FS_ERROR)
tb->nerrs--;
else
tb->nents--;
return 0;
}
/**
* mnt_tab_get_root_fs:
* @tb: mountinfo file (/proc/self/mountinfo)
* @root: returns pointer to the root filesystem (/)
*
* Returns: 0 on success or -1 case of error.
*/
int mnt_tab_get_root_fs(mnt_tab *tb, mnt_fs **root)
{
mnt_iter itr;
mnt_fs *fs;
int root_id = 0;
assert(tb);
assert(root);
if (!tb || !root)
return -1;
mnt_reset_iter(&itr, MNT_ITER_FORWARD);
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
int id = mnt_fs_get_parent_id(fs);
if (!id)
break; /* @tab is not mountinfo file? */
if (!*root || id < root_id) {
*root = fs;
root_id = id;
}
}
return root_id ? 0 : -1;
}
/**
* mnt_tab_next_child_fs:
* @tb: mountinfo file (/proc/self/mountinfo)
* @parent: parental FS
* @chld: returns the next child filesystem
*
* Note that filesystems are returned in the order how was mounted (according to
* IDs in /proc/self/mountinfo).
*
* Returns 0 on success, -1 in case of error or 1 at end of list.
*/
int mnt_tab_next_child_fs(mnt_tab *tb, mnt_iter *itr,
mnt_fs *parent, mnt_fs **chld)
{
mnt_fs *fs;
int parent_id, lastchld_id = 0, chld_id = 0;
if (!tb || !itr || !parent)
return -1;
parent_id = mnt_fs_get_id(parent);
if (!parent_id)
return -1;
/* get ID of the previously returned child */
if (itr->head && itr->p != itr->head) {
MNT_ITER_ITERATE(itr, fs, struct _mnt_fs, ents);
lastchld_id = mnt_fs_get_id(fs);
}
*chld = NULL;
mnt_reset_iter(itr, MNT_ITER_FORWARD);
while(mnt_tab_next_fs(tb, itr, &fs) == 0) {
int id;
if (mnt_fs_get_parent_id(fs) != parent_id)
continue;
id = mnt_fs_get_id(fs);
if ((!lastchld_id || id > lastchld_id) &&
(!*chld || id < chld_id)) {
*chld = fs;
chld_id = id;
}
}
if (!chld_id)
return 1; /* end of iterator */
/* set the iterator to the @chld for the next call */
mnt_tab_set_iter(tb, itr, *chld);
return 0;
}
/**
* mnt_tab_next_fs:
* @tb: tab pointer
* @itr: iterator
* @fs: returns the next tab entry
*
* Returns 0 on success, -1 in case of error or 1 at end of list.
*
* Example (list all mountpoints from fstab in backward order):
*
* mnt_fs *fs;
* mnt_tab *tb = mnt_new_tab("/etc/fstab");
* mnt_iter *itr = mnt_new_iter(MNT_ITER_BACKWARD);
*
* mnt_tab_parse_file(tb);
*
* while(mnt_tab_next_fs(tb, itr, &fs) == 0) {
* const char *dir = mnt_fs_get_target(fs);
* printf("mount point: %s\n", dir);
* }
* mnt_free_tab(fi);
*/
int mnt_tab_next_fs(mnt_tab *tb, mnt_iter *itr, mnt_fs **fs)
{
int rc;
assert(tb);
assert(itr);
assert(fs);
if (!tb || !itr || !fs)
return -1;
again:
rc = 1;
if (!itr->head)
MNT_ITER_INIT(itr, &tb->ents);
if (itr->p != itr->head) {
MNT_ITER_ITERATE(itr, *fs, struct _mnt_fs, ents);
rc = 0;
}
/* ignore broken entries */
if (*fs && ((*fs)->flags & MNT_FS_ERROR))
goto again;
return rc;
}
/**
* mnt_tab_find_next_fs:
* @tb: table
* @itr: iterator
* @match_func: function returns 1 or 0
* @fs: returns pointer to the next matching table entry
*
* This function allows search in @tb.
*
* Returns -1 in case of error, 1 at end of table or 0 o success.
*/
int mnt_tab_find_next_fs(mnt_tab *tb, mnt_iter *itr,
int (*match_func)(mnt_fs *, void *), void *userdata,
mnt_fs **fs)
{
if (!tb || !itr || !fs || !match_func)
return -1;
if (!itr->head)
MNT_ITER_INIT(itr, &tb->ents);
do {
if (itr->p != itr->head)
MNT_ITER_ITERATE(itr, *fs, struct _mnt_fs, ents);
else
break; /* end */
if ((*fs)->flags & MNT_FS_ERROR)
continue;
if (match_func(*fs, userdata))
return 0;
} while(1);
*fs = NULL;
return 1;
}
/**
* mnt_tab_set_iter:
* @tb: tab pointer
* @itr: iterator
* @fs: tab entry
*
* Sets @iter to the position of @fs in the file @tb.
*
* Returns 0 on success, -1 in case of error.
*/
int mnt_tab_set_iter(mnt_tab *tb, mnt_iter *itr, mnt_fs *fs)
{
assert(tb);
assert(itr);
assert(fs);
if (!tb || !itr || !fs)
return -1;
MNT_ITER_INIT(itr, &tb->ents);
itr->p = &fs->ents;
return 0;
}
/**
* mnt_tab_find_target:
* @tb: tab pointer
* @path: mountpoint directory
* @direction: MNT_ITER_{FORWARD,BACKWARD}
*
* Try to lookup an entry in given tab, possible are three iterations, first
* with @path, second with realpath(@path) and third with realpath(@path)
* against realpath(fs->target). The 2nd and 3rd iterations are not performed
* when @tb cache is not set (see mnt_tab_set_cache()).
*
* Returns a tab entry or NULL.
*/
mnt_fs *mnt_tab_find_target(mnt_tab *tb, const char *path, int direction)
{
mnt_iter itr;
mnt_fs *fs = NULL;
char *cn;
assert(tb);
assert(path);
DBG(DEBUG_TAB, fprintf(stderr,
"libmount: %s: lookup target: %s\n", tb->filename, path));
/* native @target */
mnt_reset_iter(&itr, direction);
while(mnt_tab_next_fs(tb, &itr, &fs) == 0)
if (fs->target && strcmp(fs->target, path) == 0)
return fs;
if (!tb->cache || !(cn = mnt_resolve_path(path, tb->cache)))
return NULL;
/* canonicalized paths in mnt_tab */
mnt_reset_iter(&itr, direction);
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
if (fs->target && strcmp(fs->target, cn) == 0)
return fs;
}
/* non-canonicaled path in mnt_tab */
mnt_reset_iter(&itr, direction);
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
char *p;
if (!fs->target)
continue;
p = mnt_resolve_path(fs->target, tb->cache);
if (strcmp(cn, p) == 0)
return fs;
}
return NULL;
}
/**
* mnt_tab_find_srcpath:
* @tb: tab pointer
* @path: source path (devname or dirname)
* @direction: MNT_ITER_{FORWARD,BACKWARD}
*
* Try to lookup an entry in given tab, possible are four iterations, first
* with @path, second with realpath(@path), third with tags (LABEL, UUID, ..)
* from @path and fourth with realpath(@path) against realpath(entry->srcpath).
*
* The 2nd, 3rd and 4th iterations are not performed when @tb cache is not
* set (see mnt_tab_set_cache()).
*
* Returns a tab entry or NULL.
*/
mnt_fs *mnt_tab_find_srcpath(mnt_tab *tb, const char *path, int direction)
{
mnt_iter itr;
mnt_fs *fs = NULL;
int ntags = 0;
char *cn;
const char *p;
assert(tb);
assert(path);
DBG(DEBUG_TAB, fprintf(stderr,
"libmount: %s: lookup srcpath: %s\n", tb->filename, path));
/* native paths */
mnt_reset_iter(&itr, direction);
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
p = mnt_fs_get_srcpath(fs);
if (p && strcmp(p, path) == 0)
return fs;
if (!p)
/* mnt_fs_get_srcpath() returs nothing, it's TAG */
ntags++;
}
if (!tb->cache || !(cn = mnt_resolve_path(path, tb->cache)))
return NULL;
/* canonicalized paths in mnt_tab */
if (ntags < mnt_tab_get_nents(tb)) {
mnt_reset_iter(&itr, direction);
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
p = mnt_fs_get_srcpath(fs);
if (p && strcmp(p, cn) == 0)
return fs;
}
}
/* evaluated tag */
if (ntags) {
mnt_reset_iter(&itr, direction);
if (mnt_cache_read_tags(tb->cache, cn) > 0) {
/* @path's TAGs are in the cache */
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
const char *t, *v;
if (mnt_fs_get_tag(fs, &t, &v))
continue;
if (mnt_cache_device_has_tag(tb->cache, cn, t, v))
return fs;
}
} else if (errno == EACCES) {
/* @path is unaccessible, try evaluate all TAGs in @tb
* by udev symlinks -- this could be expensive on systems
* with huge fstab/mtab */
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
const char *t, *v, *x;
if (mnt_fs_get_tag(fs, &t, &v))
continue;
x = mnt_resolve_tag(t, v, tb->cache);
if (x && !strcmp(x, cn))
return fs;
}
}
}
/* non-canonicalized paths in mnt_tab */
if (ntags <= mnt_tab_get_nents(tb)) {
mnt_reset_iter(&itr, direction);
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
p = mnt_fs_get_srcpath(fs);
if (p)
p = mnt_resolve_path(p, tb->cache);
if (p && strcmp(cn, p) == 0)
return fs;
}
}
return NULL;
}
/**
* mnt_tab_find_tag:
* @tb: tab pointer
* @tag: tag name (e.g "LABEL", "UUID", ...)
* @val: tag value
* @direction: MNT_ITER_{FORWARD,BACKWARD}
*
* Try to lookup an entry in given tab, first attempt is lookup by @tag and
* @val, for the second attempt the tag is evaluated (converted to the device
* name) and mnt_tab_find_srcpath() is preformed. The second attempt is not
* performed when @tb cache is not set (see mnt_tab_set_cache()).
* Returns a tab entry or NULL.
*/
mnt_fs *mnt_tab_find_tag(mnt_tab *tb, const char *tag,
const char *val, int direction)
{
mnt_iter itr;
mnt_fs *fs = NULL;
assert(tb);
assert(tag);
assert(val);
if (!tb || !tag || !val)
return NULL;
DBG(DEBUG_TAB, fprintf(stderr,
"libmount: %s: lookup by TAG: %s %s\n", tb->filename, tag, val));
/* look up by TAG */
mnt_reset_iter(&itr, direction);
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
if (fs->tagname && fs->tagval &&
strcmp(fs->tagname, tag) == 0 &&
strcmp(fs->tagval, val) == 0)
return fs;
}
if (tb->cache) {
/* look up by device name */
char *cn = mnt_resolve_tag(tag, val, tb->cache);
if (cn)
return mnt_tab_find_srcpath(tb, cn, direction);
}
return NULL;
}
/**
* mnt_tab_find_source:
* @tb: tab pointer
* @source: TAG or path
*
* This is high-level API for mnt_tab_find_{srcpath,tag}. You needn't to care
* about @source format (device, LABEL, UUID, ...). This function parses @source
* and calls mnt_tab_find_tag() or mnt_tab_find_srcpath().
*
* Returns a tab entry or NULL.
*/
mnt_fs *mnt_tab_find_source(mnt_tab *tb, const char *source, int direction)
{
mnt_fs *fs = NULL;
assert(tb);
assert(source);
if (!tb || !source)
return NULL;
DBG(DEBUG_TAB, fprintf(stderr,
"libmount: %s: lookup SOURCE: %s\n", tb->filename, source));
if (strchr(source, '=')) {
char *tag, *val;
if (blkid_parse_tag_string(source, &tag, &val) == 0) {
fs = mnt_tab_find_tag(tb, tag, val, direction);
free(tag);
free(val);
}
} else
fs = mnt_tab_find_srcpath(tb, source, direction);
return fs;
}
/**
* mnt_tab_fprintf:
* @f: FILE
* @fmt: per line printf-like format string (see MNT_MFILE_PRINTFMT)
* @tb: tab pointer
*
* Returns 0 on success, -1 in case of error.
*/
int mnt_tab_fprintf(mnt_tab *tb, FILE *f, const char *fmt)
{
mnt_iter itr;
mnt_fs *fs;
assert(f);
assert(fmt);
assert(tb);
if (!f || !fmt || !tb)
return -1;
mnt_reset_iter(&itr, MNT_ITER_FORWARD);
while(mnt_tab_next_fs(tb, &itr, &fs) == 0) {
if (mnt_fs_fprintf(fs, f, fmt) == -1)
return -1;
}
return 0;
}
/**
* mnt_tab_update_file
* @tb: tab pointer
*
* Writes tab to disk. Don't forget to lock the file (see mnt_lock()).
*
* Returns 0 on success, -1 in case of error.
*/
int mnt_tab_update_file(mnt_tab *tb)
{
FILE *f = NULL;
char tmpname[PATH_MAX];
const char *filename;
struct stat st;
int fd;
assert(tb);
if (!tb)
goto error;
filename = mnt_tab_get_name(tb);
if (!filename)
goto error;
if (snprintf(tmpname, sizeof(tmpname), "%s.tmp", filename)
>= sizeof(tmpname))
goto error;
f = fopen(tmpname, "w");
if (!f)
goto error;
if (mnt_tab_fprintf(tb, f, MNT_MFILE_PRINTFMT) != 0)
goto error;
fd = fileno(f);
if (fchmod(fd, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH) < 0)
goto error;
/* Copy uid/gid from the present file before renaming. */
if (stat(filename, &st) == 0) {
if (fchown(fd, st.st_uid, st.st_gid) < 0)
goto error;
}
fclose(f);
f = NULL;
if (rename(tmpname, filename) < 0)
goto error;
return 0;
error:
if (f)
fclose(f);
return -1;
}
#ifdef TEST_PROGRAM
int test_strerr(struct mtest *ts, int argc, char *argv[])
{
char buf[BUFSIZ];
mnt_tab *tb;
int i;
tb = mnt_new_tab("-test-");
if (!tb)
goto err;
for (i = 0; i < 10; i++) {
mnt_fs *fs = mnt_new_fs();
if (!fs)
goto err;
if (i % 2)
fs->flags |= MNT_FS_ERROR; /* mark entry as broken */
fs->lineno = i+1;
mnt_tab_add_fs(tb, fs);
}
printf("\tadded %d valid lines\n", mnt_tab_get_nents(tb));
printf("\tadded %d broken lines\n", mnt_tab_get_nerrs(tb));
if (!mnt_tab_get_nerrs(tb)) /* report broken entries */
goto err;
mnt_tab_strerror(tb, buf, sizeof(buf));
printf("\t%s\n", buf);
mnt_free_tab(tb);
return 0;
err:
return -1;
}
mnt_tab *create_tab(const char *file)
{
mnt_tab *tb;
if (!file)
return NULL;
tb = mnt_new_tab(file);
if (!tb)
goto err;
if (mnt_tab_parse_file(tb) != 0)
goto err;
if (mnt_tab_get_nerrs(tb)) {
char buf[BUFSIZ];
mnt_tab_strerror(tb, buf, sizeof(buf));
fprintf(stderr, "%s\n", buf);
goto err;
}
return tb;
err:
mnt_free_tab(tb);
return NULL;
}
int test_parse(struct mtest *ts, int argc, char *argv[])
{
mnt_tab *tb;
mnt_iter *itr;
mnt_fs *fs;
tb = create_tab(argv[1]);
if (!tb)
return -1;
itr = mnt_new_iter(MNT_ITER_FORWARD);
if (!itr)
goto err;
while(mnt_tab_next_fs(tb, itr, &fs) == 0)
mnt_fs_print_debug(fs, stdout);
err:
mnt_free_iter(itr);
mnt_free_tab(tb);
return 0;
}
int test_find(struct mtest *ts, int argc, char *argv[], int dr)
{
mnt_tab *tb;
mnt_fs *fs = NULL;
mnt_cache *mpc;
const char *file, *find, *what;
if (argc != 4) {
fprintf(stderr, "try --help\n");
goto err;
}
file = argv[1], find = argv[2], what = argv[3];
tb = create_tab(file);
if (!tb)
goto err;
/* create a cache for canonicalized paths */
mpc = mnt_new_cache();
if (!mpc)
goto err;
mnt_tab_set_cache(tb, mpc);
if (strcasecmp(find, "source") == 0)
fs = mnt_tab_find_source(tb, what, dr);
else if (strcasecmp(find, "target") == 0)
fs = mnt_tab_find_target(tb, what, dr);
if (!fs)
fprintf(stderr, "%s: not found %s '%s'\n", file, find, what);
else {
const char *s = mnt_fs_get_srcpath(fs);
if (s)
printf("%s", s);
else {
const char *tag, *val;
mnt_fs_get_tag(fs, &tag, &val);
printf("%s=%s", tag, val);
}
printf("|%s|%s\n", mnt_fs_get_target(fs),
mnt_fs_get_optstr(fs));
}
mnt_free_tab(tb);
mnt_free_cache(mpc);
return 0;
err:
return -1;
}
int test_find_bw(struct mtest *ts, int argc, char *argv[])
{
return test_find(ts, argc, argv, MNT_ITER_BACKWARD);
}
int test_find_fw(struct mtest *ts, int argc, char *argv[])
{
return test_find(ts, argc, argv, MNT_ITER_FORWARD);
}
int main(int argc, char *argv[])
{
struct mtest tss[] = {
{ "--strerror", test_strerr, " test tab error reporting" },
{ "--parse", test_parse, "<file> parse and print tab" },
{ "--find-forward", test_find_fw, "<file> <source|target> <string>" },
{ "--find-backward", test_find_bw, "<file> <source|target> <string>" },
{ NULL }
};
return mnt_run_test(tss, argc, argv);
}
#endif /* TEST_PROGRAM */
