diff options
Diffstat (limited to 'src/mtab.c')
| -rw-r--r-- | src/mtab.c | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/src/mtab.c b/src/mtab.c new file mode 100644 index 0000000..adc3f58 --- /dev/null +++ b/src/mtab.c @@ -0,0 +1,246 @@ +/**************************************************************************** + * bfs * + * Copyright (C) 2017-2020 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 "stat.h" +#include "trie.h" +#include "util.h" +#include <errno.h> +#include <fcntl.h> +#include <stdbool.h> +#include <stdlib.h> +#include <string.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 *bfs_mtab_parse(void) { + 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 + +#if __NetBSD__ + typedef struct statvfs bfs_statfs; +#else + typedef struct statfs bfs_statfs; +#endif + + bfs_statfs *mntbuf; + int size = getmntinfo(&mntbuf, MNT_WAIT); + if (size < 0) { + error = errno; + goto fail; + } + + for (bfs_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 = xfopen(MNTTAB, O_RDONLY | O_CLOEXEC); + 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: + bfs_mtab_free(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_might_be_mount(const struct bfs_mtab *mtab, const char *path) { + const char *name = xbasename(path); + return trie_find_str(&mtab->names, name); +} + +void bfs_mtab_free(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); + } +} |