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/****************************************************************************
* bfs *
* Copyright (C) 2017-2019 Tavian Barnes <tavianator@tavianator.com> *
* *
* Permission to use, copy, modify, and/or distribute this software for any *
* purpose with or without fee is hereby granted. *
* *
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF *
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR *
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES *
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN *
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF *
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *
****************************************************************************/
#include "mtab.h"
#include "darray.h"
#include "trie.h"
#include "util.h"
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#if BFS_HAS_SYS_PARAM
# include <sys/param.h>
#endif
#if BFS_HAS_MNTENT
# define BFS_MNTENT 1
#elif BSD
# define BFS_MNTINFO 1
#elif __SVR4
# define BFS_MNTTAB 1
#endif
#if BFS_MNTENT
# include <mntent.h>
# include <paths.h>
# include <stdio.h>
#elif BFS_MNTINFO
# include <sys/mount.h>
# include <sys/ucred.h>
#elif BFS_MNTTAB
# include <stdio.h>
# include <sys/mnttab.h>
#endif
/**
* A mount point in the table.
*/
struct bfs_mtab_entry {
/** The path to the mount point. */
char *path;
/** The filesystem type. */
char *type;
};
struct bfs_mtab {
/** The list of mount points. */
struct bfs_mtab_entry *entries;
/** The basenames of every mount point. */
struct trie names;
/** A map from device ID to fstype (populated lazily). */
struct trie types;
/** Whether the types map has been populated. */
bool types_filled;
};
/**
* Add an entry to the mount table.
*/
static int bfs_mtab_add(struct bfs_mtab *mtab, const char *path, const char *type) {
struct bfs_mtab_entry entry = {
.path = strdup(path),
.type = strdup(type),
};
if (!entry.path || !entry.type) {
goto fail_entry;
}
if (DARRAY_PUSH(&mtab->entries, &entry) != 0) {
goto fail_entry;
}
if (!trie_insert_str(&mtab->names, xbasename(path))) {
goto fail;
}
return 0;
fail_entry:
free(entry.type);
free(entry.path);
fail:
return -1;
}
struct bfs_mtab *parse_bfs_mtab() {
struct bfs_mtab *mtab = malloc(sizeof(*mtab));
if (!mtab) {
return NULL;
}
mtab->entries = NULL;
trie_init(&mtab->names);
trie_init(&mtab->types);
mtab->types_filled = false;
int error = 0;
#if BFS_MNTENT
FILE *file = setmntent(_PATH_MOUNTED, "r");
if (!file) {
// In case we're in a chroot or something with /proc but no /etc/mtab
error = errno;
file = setmntent("/proc/mounts", "r");
}
if (!file) {
goto fail;
}
struct mntent *mnt;
while ((mnt = getmntent(file))) {
if (bfs_mtab_add(mtab, mnt->mnt_dir, mnt->mnt_type) != 0) {
error = errno;
endmntent(file);
goto fail;
}
}
endmntent(file);
#elif BFS_MNTINFO
struct statfs *mntbuf;
int size = getmntinfo(&mntbuf, MNT_WAIT);
if (size < 0) {
error = errno;
goto fail;
}
for (struct statfs *mnt = mntbuf; mnt < mntbuf + size; ++mnt) {
if (bfs_mtab_add(mtab, mnt->f_mntonname, mnt->f_fstypename) != 0) {
error = errno;
goto fail;
}
}
#elif BFS_MNTTAB
FILE *file = fopen(MNTTAB, "r");
if (!file) {
error = errno;
goto fail;
}
struct mnttab mnt;
while (getmntent(file, &mnt) == 0) {
if (bfs_mtab_add(mtab, mnt.mnt_mountp, mnt.mnt_fstype) != 0) {
error = errno;
fclose(file);
goto fail;
}
}
fclose(file);
#else
error = ENOTSUP;
goto fail;
#endif
return mtab;
fail:
free_bfs_mtab(mtab);
errno = error;
return NULL;
}
static void bfs_mtab_fill_types(struct bfs_mtab *mtab) {
for (size_t i = 0; i < darray_length(mtab->entries); ++i) {
struct bfs_mtab_entry *entry = mtab->entries + i;
struct bfs_stat sb;
if (bfs_stat(AT_FDCWD, entry->path, BFS_STAT_NOFOLLOW | BFS_STAT_NOSYNC, &sb) != 0) {
continue;
}
struct trie_leaf *leaf = trie_insert_mem(&mtab->types, &sb.dev, sizeof(sb.dev));
if (leaf) {
leaf->value = entry->type;
}
}
mtab->types_filled = true;
}
const char *bfs_fstype(const struct bfs_mtab *mtab, const struct bfs_stat *statbuf) {
if (!mtab->types_filled) {
bfs_mtab_fill_types((struct bfs_mtab *)mtab);
}
const struct trie_leaf *leaf = trie_find_mem(&mtab->types, &statbuf->dev, sizeof(statbuf->dev));
if (leaf) {
return leaf->value;
} else {
return "unknown";
}
}
bool bfs_maybe_mount(const struct bfs_mtab *mtab, const char *path) {
const char *name = xbasename(path);
return trie_find_str(&mtab->names, name);
}
void free_bfs_mtab(struct bfs_mtab *mtab) {
if (mtab) {
trie_destroy(&mtab->types);
trie_destroy(&mtab->names);
for (size_t i = 0; i < darray_length(mtab->entries); ++i) {
free(mtab->entries[i].type);
free(mtab->entries[i].path);
}
darray_free(mtab->entries);
free(mtab);
}
}
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