diff options
Diffstat (limited to 'libmount/src/utils.c')
-rw-r--r-- | libmount/src/utils.c | 991 |
1 files changed, 991 insertions, 0 deletions
diff --git a/libmount/src/utils.c b/libmount/src/utils.c new file mode 100644 index 0000000..63d1079 --- /dev/null +++ b/libmount/src/utils.c @@ -0,0 +1,991 @@ +/* + * Copyright (C) 2008-2009 Karel Zak <kzak@redhat.com> + * + * This file may be redistributed under the terms of the + * GNU Lesser General Public License. + */ + +/** + * SECTION: utils + * @title: Utils + * @short_description: misc utils. + */ +#include <ctype.h> +#include <fcntl.h> +#include <pwd.h> +#include <grp.h> + +#include "strutils.h" +#include "pathnames.h" +#include "mountP.h" +#include "mangle.h" +#include "canonicalize.h" +#include "env.h" +#include "match.h" + +int endswith(const char *s, const char *sx) +{ + ssize_t off; + + assert(s); + assert(sx); + + off = strlen(s); + if (!off) + return 0; + off -= strlen(sx); + if (off < 0) + return 0; + + return !strcmp(s + off, sx); +} + +int startswith(const char *s, const char *sx) +{ + size_t off; + + assert(s); + assert(sx); + + off = strlen(sx); + if (!off) + return 0; + + return !strncmp(s, sx, off); +} + +int mnt_parse_offset(const char *str, size_t len, uintmax_t *res) +{ + char *p; + int rc = 0; + + if (!str || !*str) + return -EINVAL; + + p = strndup(str, len); + if (!p) + return -errno; + + if (strtosize(p, res)) + rc = -EINVAL; + free(p); + return rc; +} + +/* used as a callback by bsearch in mnt_fstype_is_pseudofs() */ +static int fstype_cmp(const void *v1, const void *v2) +{ + const char *s1 = *(const char **)v1; + const char *s2 = *(const char **)v2; + + return strcmp(s1, s2); +} + +/* returns basename and keeps dirname in the @path, if @path is "/" (root) + * then returns empty string */ +static char *stripoff_last_component(char *path) +{ + char *p = path ? strrchr(path, '/') : NULL; + + if (!p) + return NULL; + *p = '\0'; + return p + 1; +} + +/* + * Note that the @target has to be absolute path (so at least "/"). The + * @filename returns allocated buffer with last path component, for example: + * + * mnt_chdir_to_parent("/mnt/test", &buf) ==> chdir("/mnt"), buf="test" + */ +int mnt_chdir_to_parent(const char *target, char **filename) +{ + char *buf, *parent, *last = NULL; + char cwd[PATH_MAX]; + int rc = -EINVAL; + + if (!target || *target != '/') + return -EINVAL; + + DBG(UTILS, mnt_debug("moving to %s parent", target)); + + buf = strdup(target); + if (!buf) + return -ENOMEM; + + if (*(buf + 1) != '\0') { + last = stripoff_last_component(buf); + if (!last) + goto err; + } + + parent = buf && *buf ? buf : "/"; + + if (chdir(parent) == -1) { + DBG(UTILS, mnt_debug("failed to chdir to %s: %m", parent)); + rc = -errno; + goto err; + } + if (!getcwd(cwd, sizeof(cwd))) { + DBG(UTILS, mnt_debug("failed to obtain current directory: %m")); + rc = -errno; + goto err; + } + if (strcmp(cwd, parent) != 0) { + DBG(UTILS, mnt_debug( + "unexpected chdir (expected=%s, cwd=%s)", parent, cwd)); + goto err; + } + + DBG(CXT, mnt_debug( + "current directory moved to %s [last_component='%s']", + parent, last)); + + *filename = buf; + + if (!last || !*last) + memcpy(*filename, ".", 2); + else + memcpy(*filename, last, strlen(last) + 1); + return 0; +err: + free(buf); + return rc; +} + +/* + * Check if @path is on read-only filesystem independently on file permissions. + */ +int mnt_is_readonly(const char *path) +{ + if (access(path, W_OK) == 0) + return 0; + if (errno == EROFS) + return 1; + if (errno != EACCES) + return 0; + +#ifdef HAVE_FUTIMENS + /* + * access(2) returns EACCES on read-only FS: + * + * - for set-uid application if one component of the path is not + * accessible for the current rUID. (Note that euidaccess(2) does not + * check for EROFS at all). + * + * - for read-write filesystem with read-only VFS node (aka -o remount,ro,bind) + */ + { + struct timespec times[2]; + + times[0].tv_nsec = UTIME_NOW; /* atime */ + times[1].tv_nsec = UTIME_OMIT; /* mtime */ + + if (utimensat(AT_FDCWD, path, times, 0) == -1) + return errno == EROFS; + } +#endif + return 0; +} + +/** + * mnt_mangle: + * @str: string + * + * Encode @str to be compatible with fstab/mtab + * + * Returns: new allocated string or NULL in case of error. + */ +char *mnt_mangle(const char *str) +{ + return mangle(str); +} + +/** + * mnt_unmangle: + * @str: string + * + * Decode @str from fstab/mtab + * + * Returns: new allocated string or NULL in case of error. + */ +char *mnt_unmangle(const char *str) +{ + return unmangle(str, NULL); +} + +/** + * mnt_fstype_is_pseudofs: + * @type: filesystem name + * + * Returns: 1 for filesystems like proc, sysfs, ... or 0. + */ +int mnt_fstype_is_pseudofs(const char *type) +{ + /* This array must remain sorted when adding new fstypes */ + static const char *pseudofs[] = { + "anon_inodefs", + "autofs", + "bdev", + "binfmt_misc", + "cgroup", + "configfs", + "cpuset", + "debugfs", + "devfs", + "devpts", + "devtmpfs", + "dlmfs", + "fuse.gvfs-fuse-daemon", + "fusectl", + "hugetlbfs", + "mqueue", + "nfsd", + "none", + "pipefs", + "proc", + "pstore", + "ramfs", + "rootfs", + "rpc_pipefs", + "securityfs", + "sockfs", + "spufs", + "sysfs", + "tmpfs" + }; + + return !(bsearch(&type, pseudofs, ARRAY_SIZE(pseudofs), + sizeof(char*), fstype_cmp) == NULL); +} + +/** + * mnt_fstype_is_netfs: + * @type: filesystem name + * + * Returns: 1 for filesystems like cifs, nfs, ... or 0. + */ +int mnt_fstype_is_netfs(const char *type) +{ + if (!type) + return 0; + if (strcmp(type, "cifs") == 0 || + strcmp(type, "smbfs") == 0 || + strncmp(type,"nfs", 3) == 0 || + strcmp(type, "afs") == 0 || + strcmp(type, "ncpfs") == 0 || + strncmp(type,"9p", 2) == 0) + return 1; + return 0; +} + +/** + * mnt_match_fstype: + * @type: filesystem type + * @pattern: filesystem name or comma delimited list of names + * + * The @pattern list of filesystem can be prefixed with a global + * "no" prefix to invert matching of the whole list. The "no" could + * also be used for individual items in the @pattern list. So, + * "nofoo,bar" has the same meaning as "nofoo,nobar". + * + * "bar" : "nofoo,bar" -> False (global "no" prefix) + * + * "bar" : "foo,bar" -> True + * + * "bar" : "foo,nobar" -> False + * + * Returns: 1 if type is matching, else 0. This function also returns + * 0 if @pattern is NULL and @type is non-NULL. + */ +int mnt_match_fstype(const char *type, const char *pattern) +{ + return match_fstype(type, pattern); +} + + +/* Returns 1 if needle found or noneedle not found in haystack + * Otherwise returns 0 + */ +static int check_option(const char *haystack, size_t len, + const char *needle, size_t needle_len) +{ + const char *p; + int no = 0; + + if (needle_len >= 1 && *needle == '+') { + needle++; + needle_len--; + } else if (needle_len >= 2 && !strncmp(needle, "no", 2)) { + no = 1; + needle += 2; + needle_len -= 2; + } + + for (p = haystack; p && p < haystack + len; p++) { + char *sep = strchr(p, ','); + size_t plen = sep ? (size_t) (sep - p) : + len - (p - haystack); + + if (plen == needle_len) { + if (!strncmp(p, needle, plen)) + return !no; /* foo or nofoo was found */ + } + p += plen; + } + + return no; /* foo or nofoo was not found */ +} + +/** + * mnt_match_options: + * @optstr: options string + * @pattern: comma delimited list of options + * + * The "no" could used for individual items in the @options list. The "no" + * prefix does not have a global meaning. + * + * Unlike fs type matching, nonetdev,user and nonetdev,nouser have + * DIFFERENT meanings; each option is matched explicitly as specified. + * + * The "no" prefix interpretation could be disable by "+" prefix, for example + * "+noauto" matches if @optstr literally contains "noauto" string. + * + * "xxx,yyy,zzz" : "nozzz" -> False + * + * "xxx,yyy,zzz" : "xxx,noeee" -> True + * + * "bar,zzz" : "nofoo" -> True + * + * "nofoo,bar" : "+nofoo" -> True + * + * "bar,zzz" : "+nofoo" -> False + * + * + * Returns: 1 if pattern is matching, else 0. This function also returns 0 + * if @pattern is NULL and @optstr is non-NULL. + */ +int mnt_match_options(const char *optstr, const char *pattern) +{ + const char *p; + size_t len, optstr_len = 0; + + if (!pattern && !optstr) + return 1; + if (!pattern) + return 0; + + len = strlen(pattern); + if (optstr) + optstr_len = strlen(optstr); + + for (p = pattern; p < pattern + len; p++) { + char *sep = strchr(p, ','); + size_t plen = sep ? (size_t) (sep - p) : + len - (p - pattern); + + if (!plen) + continue; /* if two ',' appear in a row */ + + if (!check_option(optstr, optstr_len, p, plen)) + return 0; /* any match failure means failure */ + + p += plen; + } + + /* no match failures in list means success */ + return 1; +} + +void mnt_free_filesystems(char **filesystems) +{ + char **p; + + if (!filesystems) + return; + for (p = filesystems; *p; p++) + free(*p); + free(filesystems); +} + +static int add_filesystem(char ***filesystems, char *name) +{ + int n = 0; + + assert(filesystems); + assert(name); + + if (*filesystems) { + char **p; + for (n = 0, p = *filesystems; *p; p++, n++) { + if (strcmp(*p, name) == 0) + return 0; + } + } + + #define MYCHUNK 16 + + if (n == 0 || !((n + 1) % MYCHUNK)) { + size_t items = ((n + 1 + MYCHUNK) / MYCHUNK) * MYCHUNK; + char **x = realloc(*filesystems, items * sizeof(char *)); + + if (!x) + goto err; + *filesystems = x; + } + name = strdup(name); + if (!name) + goto err; + (*filesystems)[n] = name; + (*filesystems)[n + 1] = NULL; + return 0; +err: + mnt_free_filesystems(*filesystems); + return -ENOMEM; +} + +static int get_filesystems(const char *filename, char ***filesystems, const char *pattern) +{ + int rc = 0; + FILE *f; + char line[128]; + + f = fopen(filename, "r"); + if (!f) + return 0; + + while (fgets(line, sizeof(line), f)) { + char name[sizeof(line)]; + + if (*line == '#' || strncmp(line, "nodev", 5) == 0) + continue; + if (sscanf(line, " %128[^\n ]\n", name) != 1) + continue; + if (pattern && !mnt_match_fstype(name, pattern)) + continue; + rc = add_filesystem(filesystems, name); + if (rc) + break; + } + + fclose(f); + return rc; +} + +int mnt_get_filesystems(char ***filesystems, const char *pattern) +{ + int rc; + + if (!filesystems) + return -EINVAL; + *filesystems = NULL; + + rc = get_filesystems(_PATH_FILESYSTEMS, filesystems, pattern); + if (rc) + return rc; + return get_filesystems(_PATH_PROC_FILESYSTEMS, filesystems, pattern); +} + +static size_t get_pw_record_size(void) +{ +#ifdef _SC_GETPW_R_SIZE_MAX + long sz = sysconf(_SC_GETPW_R_SIZE_MAX); + if (sz > 0) + return sz; +#endif + return 16384; +} + +/* + * Returns allocated string with username or NULL. + */ +char *mnt_get_username(const uid_t uid) +{ + struct passwd pwd; + struct passwd *res; + size_t sz = get_pw_record_size(); + char *buf, *username = NULL; + + buf = malloc(sz); + if (!buf) + return NULL; + + if (!getpwuid_r(uid, &pwd, buf, sz, &res) && res) + username = strdup(pwd.pw_name); + + free(buf); + return username; +} + +int mnt_get_uid(const char *username, uid_t *uid) +{ + int rc = -1; + struct passwd pwd; + struct passwd *pw; + size_t sz = get_pw_record_size(); + char *buf; + + if (!username || !uid) + return -EINVAL; + + buf = malloc(sz); + if (!buf) + return -ENOMEM; + + if (!getpwnam_r(username, &pwd, buf, sz, &pw) && pw) { + *uid= pw->pw_uid; + rc = 0; + } else { + DBG(UTILS, mnt_debug( + "cannot convert '%s' username to UID", username)); + rc = errno ? -errno : -EINVAL; + } + + free(buf); + return rc; +} + +int mnt_get_gid(const char *groupname, gid_t *gid) +{ + int rc = -1; + struct group grp; + struct group *gr; + size_t sz = get_pw_record_size(); + char *buf; + + if (!groupname || !gid) + return -EINVAL; + + buf = malloc(sz); + if (!buf) + return -ENOMEM; + + if (!getgrnam_r(groupname, &grp, buf, sz, &gr) && gr) { + *gid= gr->gr_gid; + rc = 0; + } else { + DBG(UTILS, mnt_debug( + "cannot convert '%s' groupname to GID", groupname)); + rc = errno ? -errno : -EINVAL; + } + + free(buf); + return rc; +} + +int mnt_in_group(gid_t gid) +{ + int rc = 0, n, i; + gid_t *grps = NULL; + + if (getgid() == gid) + return 1; + + n = getgroups(0, NULL); + if (n <= 0) + goto done; + + grps = malloc(n * sizeof(*grps)); + if (!grps) + goto done; + + if (getgroups(n, grps) == n) { + for (i = 0; i < n; i++) { + if (grps[i] == gid) { + rc = 1; + break; + } + } + } +done: + free(grps); + return rc; +} + +static int try_write(const char *filename) +{ + int fd; + + if (!filename) + return -EINVAL; + + fd = open(filename, O_RDWR|O_CREAT, S_IWUSR| \ + S_IRUSR|S_IRGRP|S_IROTH); + if (fd >= 0) { + close(fd); + return 0; + } + return -errno; +} + +/** + * mnt_has_regular_mtab: + * @mtab: returns path to mtab + * @writable: returns 1 if the file is writable + * + * If the file does not exist and @writable argument is not NULL then it will + * try to create the file + * + * Returns: 1 if /etc/mtab is a regular file, and 0 in case of error (check + * errno for more details). + */ +int mnt_has_regular_mtab(const char **mtab, int *writable) +{ + struct stat st; + int rc; + const char *filename = mtab && *mtab ? *mtab : mnt_get_mtab_path(); + + if (writable) + *writable = 0; + if (mtab && !*mtab) + *mtab = filename; + + DBG(UTILS, mnt_debug("mtab: %s", filename)); + + rc = lstat(filename, &st); + + if (rc == 0) { + /* file exist */ + if (S_ISREG(st.st_mode)) { + if (writable) + *writable = !try_write(filename); + return 1; + } + goto done; + } + + /* try to create the file */ + if (writable) { + *writable = !try_write(filename); + if (*writable) + return 1; + } + +done: + DBG(UTILS, mnt_debug("%s: irregular/non-writable", filename)); + return 0; +} + +/* + * Don't export this to libmount API -- utab is private library stuff. + * + * If the file does not exist and @writable argument is not NULL then it will + * try to create the directory (e.g. /run/mount) and the file. + * + * Returns: 1 if utab is a regular file, and 0 in case of + * error (check errno for more details). + */ +int mnt_has_regular_utab(const char **utab, int *writable) +{ + struct stat st; + int rc; + const char *filename = utab && *utab ? *utab : mnt_get_utab_path(); + + if (writable) + *writable = 0; + if (utab && !*utab) + *utab = filename; + + DBG(UTILS, mnt_debug("utab: %s", filename)); + + rc = lstat(filename, &st); + + if (rc == 0) { + /* file exist */ + if (S_ISREG(st.st_mode)) { + if (writable) + *writable = !try_write(filename); + return 1; + } + goto done; /* it's not regular file */ + } + + if (writable) { + char *dirname = strdup(filename); + + if (!dirname) + goto done; + + stripoff_last_component(dirname); /* remove filename */ + + rc = mkdir(dirname, S_IWUSR| + S_IRUSR|S_IRGRP|S_IROTH| + S_IXUSR|S_IXGRP|S_IXOTH); + free(dirname); + if (rc && errno != EEXIST) + goto done; /* probably EACCES */ + + *writable = !try_write(filename); + if (*writable) + return 1; + } +done: + DBG(UTILS, mnt_debug("%s: irregular/non-writable file", filename)); + return 0; +} + +/** + * mnt_get_swaps_path: + * + * Returns: path to /proc/swaps or $LIBMOUNT_SWAPS. + */ +const char *mnt_get_swaps_path(void) +{ + const char *p = safe_getenv("LIBMOUNT_SWAPS"); + return p ? : _PATH_PROC_SWAPS; +} + +/** + * mnt_get_fstab_path: + * + * Returns: path to /etc/fstab or $LIBMOUNT_FSTAB. + */ +const char *mnt_get_fstab_path(void) +{ + const char *p = safe_getenv("LIBMOUNT_FSTAB"); + return p ? : _PATH_MNTTAB; +} + +/** + * mnt_get_mtab_path: + * + * This function returns *default* location of the mtab file. The result does + * not have to be writable. See also mnt_has_regular_mtab(). + * + * Returns: path to /etc/mtab or $LIBMOUNT_MTAB. + */ +const char *mnt_get_mtab_path(void) +{ + const char *p = safe_getenv("LIBMOUNT_MTAB"); + return p ? : _PATH_MOUNTED; +} + +/* + * Don't export this to libmount API -- utab is private library stuff. + * + * Returns: path to /run/mount/utab (or /dev/.mount/utab) or $LIBMOUNT_UTAB. + */ +const char *mnt_get_utab_path(void) +{ + struct stat st; + const char *p = safe_getenv("LIBMOUNT_UTAB"); + + if (p) + return p; + + if (stat(MNT_RUNTIME_TOPDIR, &st) == 0) + return MNT_PATH_UTAB; + + return MNT_PATH_UTAB_OLD; +} + + +/* returns file descriptor or -errno, @name returns uniques filename + */ +int mnt_open_uniq_filename(const char *filename, char **name) +{ + int rc, fd; + char *n; + + assert(filename); + + if (name) + *name = NULL; + + rc = asprintf(&n, "%s.XXXXXX", filename); + if (rc <= 0) + return -errno; + + fd = mkstemp(n); + if (fd >= 0 && name) + *name = n; + else + free(n); + + return fd < 0 ? -errno : fd; +} + +/** + * mnt_get_mountpoint: + * @path: pathname + * + * This function finds the mountpoint that a given path resides in. @path + * should be canonicalized. The returned pointer should be freed by the caller. + * + * Returns: target of mounted device or NULL on error + */ +char *mnt_get_mountpoint(const char *path) +{ + char *mnt = strdup(path); + struct stat st; + dev_t dir, base; + + if (!mnt) + return NULL; + if (*mnt == '/' && *(mnt + 1) == '\0') + goto done; + + if (stat(mnt, &st)) + goto err; + base = st.st_dev; + + do { + char *p = stripoff_last_component(mnt); + + if (!p) + break; + if (stat(*mnt ? mnt : "/", &st)) + goto err; + dir = st.st_dev; + if (dir != base) { + if (p > mnt) + *(p - 1) = '/'; + goto done; + } + base = dir; + } while (mnt && *(mnt + 1) != '\0'); + + memcpy(mnt, "/", 2); +done: + DBG(UTILS, mnt_debug("%s mountpoint is %s", path, mnt)); + return mnt; +err: + free(mnt); + return NULL; +} + +char *mnt_get_fs_root(const char *path, const char *mnt) +{ + char *m = (char *) mnt, *res; + const char *p; + size_t sz; + + if (!m) + m = mnt_get_mountpoint(path); + if (!m) + return NULL; + + sz = strlen(m); + p = sz > 1 ? path + sz : path; + + if (m != mnt) + free(m); + + res = *p ? strdup(p) : strdup("/"); + DBG(UTILS, mnt_debug("%s fs-root is %s", path, res)); + return res; +} + +#ifdef TEST_PROGRAM +int test_match_fstype(struct libmnt_test *ts, int argc, char *argv[]) +{ + char *type = argv[1]; + char *pattern = argv[2]; + + printf("%s\n", mnt_match_fstype(type, pattern) ? "MATCH" : "NOT-MATCH"); + return 0; +} + +int test_match_options(struct libmnt_test *ts, int argc, char *argv[]) +{ + char *optstr = argv[1]; + char *pattern = argv[2]; + + printf("%s\n", mnt_match_options(optstr, pattern) ? "MATCH" : "NOT-MATCH"); + return 0; +} + +int test_startswith(struct libmnt_test *ts, int argc, char *argv[]) +{ + char *optstr = argv[1]; + char *pattern = argv[2]; + + printf("%s\n", startswith(optstr, pattern) ? "YES" : "NOT"); + return 0; +} + +int test_endswith(struct libmnt_test *ts, int argc, char *argv[]) +{ + char *optstr = argv[1]; + char *pattern = argv[2]; + + printf("%s\n", endswith(optstr, pattern) ? "YES" : "NOT"); + return 0; +} + +int test_mountpoint(struct libmnt_test *ts, int argc, char *argv[]) +{ + char *path = canonicalize_path(argv[1]), + *mnt = path ? mnt_get_mountpoint(path) : NULL; + + printf("%s: %s\n", argv[1], mnt ? : "unknown"); + free(mnt); + free(path); + return 0; +} + +int test_fsroot(struct libmnt_test *ts, int argc, char *argv[]) +{ + char *path = canonicalize_path(argv[1]), + *mnt = path ? mnt_get_fs_root(path, NULL) : NULL; + + printf("%s: %s\n", argv[1], mnt ? : "unknown"); + free(mnt); + free(path); + return 0; +} + +int test_filesystems(struct libmnt_test *ts, int argc, char *argv[]) +{ + char **filesystems = NULL; + int rc; + + rc = mnt_get_filesystems(&filesystems, argc ? argv[1] : NULL); + if (!rc) { + char **p; + for (p = filesystems; *p; p++) + printf("%s\n", *p); + mnt_free_filesystems(filesystems); + } + return rc; +} + +int test_chdir(struct libmnt_test *ts, int argc, char *argv[]) +{ + int rc; + char *path = canonicalize_path(argv[1]), + *last = NULL; + + if (!path) + return -errno; + + rc = mnt_chdir_to_parent(path, &last); + if (!rc) { + printf("path='%s', abs='%s', last='%s'\n", + argv[1], path, last); + } + free(path); + free(last); + return rc; +} + + +int main(int argc, char *argv[]) +{ + struct libmnt_test tss[] = { + { "--match-fstype", test_match_fstype, "<type> <pattern> FS types matching" }, + { "--match-options", test_match_options, "<options> <pattern> options matching" }, + { "--filesystems", test_filesystems, "[<pattern>] list /{etc,proc}/filesystems" }, + { "--starts-with", test_startswith, "<string> <prefix>" }, + { "--ends-with", test_endswith, "<string> <prefix>" }, + { "--mountpoint", test_mountpoint, "<path>" }, + { "--fs-root", test_fsroot, "<path>" }, + { "--cd-parent", test_chdir, "<path>" }, + { NULL } + }; + + return mnt_run_test(tss, argc, argv); +} + +#endif /* TEST_PROGRAM */ |