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Diffstat (limited to 'libmount/src/utils.c')
| -rw-r--r-- | libmount/src/utils.c | 1315 |
1 files changed, 1315 insertions, 0 deletions
diff --git a/libmount/src/utils.c b/libmount/src/utils.c new file mode 100644 index 0000000..9d6047f --- /dev/null +++ b/libmount/src/utils.c @@ -0,0 +1,1315 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * This file is part of libmount from util-linux project. + * + * Copyright (C) 2008-2018 Karel Zak <kzak@redhat.com> + * + * libmount is free software; you can redistribute it and/or modify it + * under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or + * (at your option) any later version. + */ + +/** + * SECTION: utils + * @title: Utils + * @short_description: misc utils. + */ +#include <ctype.h> +#include <fcntl.h> +#include <pwd.h> +#include <grp.h> +#include <blkid.h> + +#include "strutils.h" +#include "pathnames.h" +#include "mountP.h" +#include "mangle.h" +#include "canonicalize.h" +#include "env.h" +#include "match.h" +#include "fileutils.h" +#include "statfs_magic.h" +#include "sysfs.h" + +int append_string(char **a, const char *b) +{ + size_t al, bl; + char *tmp; + + assert(a); + + if (!b || !*b) + return 0; + if (!*a) { + *a = strdup(b); + return !*a ? -ENOMEM : 0; + } + + al = strlen(*a); + bl = strlen(b); + + tmp = realloc(*a, al + bl + 1); + if (!tmp) + return -ENOMEM; + *a = tmp; + memcpy((*a) + al, b, bl + 1); + return 0; +} + +/* + * Return 1 if the file is not accessible or empty + */ +int is_file_empty(const char *name) +{ + struct stat st; + assert(name); + + return (stat(name, &st) != 0 || st.st_size == 0); +} + +int mnt_valid_tagname(const char *tagname) +{ + if (tagname && *tagname && ( + strcmp("UUID", tagname) == 0 || + strcmp("LABEL", tagname) == 0 || + strcmp("PARTUUID", tagname) == 0 || + strcmp("PARTLABEL", tagname) == 0)) + return 1; + + return 0; +} + +/** + * mnt_tag_is_valid: + * @tag: NAME=value string + * + * Returns: 1 if the @tag is parsable and tag NAME= is supported by libmount, or 0. + */ +int mnt_tag_is_valid(const char *tag) +{ + char *t = NULL; + int rc = tag && blkid_parse_tag_string(tag, &t, NULL) == 0 + && mnt_valid_tagname(t); + + free(t); + return rc; +} + +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 = *(char * const *)v1; + const char *s2 = *(char * const *)v2; + + return strcmp(s1, s2); +} + +int mnt_stat_mountpoint(const char *target, struct stat *st) +{ +#ifdef AT_NO_AUTOMOUNT + return fstatat(AT_FDCWD, target, st, AT_NO_AUTOMOUNT); +#else + return stat(target, st); +#endif +} + +/* + * Note that the @target has to be an absolute path (so at least "/"). The + * @filename returns an allocated buffer with the 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, ul_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, ul_debug("failed to chdir to %s: %m", parent)); + rc = -errno; + goto err; + } + if (!getcwd(cwd, sizeof(cwd))) { + DBG(UTILS, ul_debug("failed to obtain current directory: %m")); + rc = -errno; + goto err; + } + if (strcmp(cwd, parent) != 0) { + DBG(UTILS, ul_debug( + "unexpected chdir (expected=%s, cwd=%s)", parent, cwd)); + goto err; + } + + DBG(CXT, ul_debug( + "current directory moved to %s [last_component='%s']", + parent, last)); + + if (filename) { + *filename = buf; + + if (!last || !*last) + memcpy(*filename, ".", 2); + else + memmove(*filename, last, strlen(last) + 1); + } else + free(buf); + return 0; +err: + free(buf); + return rc; +} + +/* + * Check if @path is on a read-only filesystem independently of 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_UTIMENSAT + /* + * 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 a read-write filesystem with a read-only VFS node (aka -o remount,ro,bind) + */ + { + struct timespec times[2]; + + DBG(UTILS, ul_debug(" doing utimensat() based write test")); + + 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: newly 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: newly 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", + "cgroup2", + "configfs", + "cpuset", + "debugfs", + "devfs", + "devpts", + "devtmpfs", + "dlmfs", + "efivarfs", + "fuse.gvfs-fuse-daemon", + "fusectl", + "hugetlbfs", + "mqueue", + "nfsd", + "none", + "nsfs", + "overlay", + "pipefs", + "proc", + "pstore", + "ramfs", + "rootfs", + "rpc_pipefs", + "securityfs", + "sockfs", + "spufs", + "sysfs", + "tmpfs" + }; + + assert(type); + + 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 (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; +} + +const char *mnt_statfs_get_fstype(struct statfs *vfs) +{ + assert(vfs); + + switch (vfs->f_type) { + case STATFS_ADFS_MAGIC: return "adfs"; + case STATFS_AFFS_MAGIC: return "affs"; + case STATFS_AFS_MAGIC: return "afs"; + case STATFS_AUTOFS_MAGIC: return "autofs"; + case STATFS_BDEVFS_MAGIC: return "bdev"; + case STATFS_BEFS_MAGIC: return "befs"; + case STATFS_BFS_MAGIC: return "befs"; + case STATFS_BINFMTFS_MAGIC: return "binfmt_misc"; + case STATFS_BTRFS_MAGIC: return "btrfs"; + case STATFS_CEPH_MAGIC: return "ceph"; + case STATFS_CGROUP_MAGIC: return "cgroup"; + case STATFS_CIFS_MAGIC: return "cifs"; + case STATFS_CODA_MAGIC: return "coda"; + case STATFS_CONFIGFS_MAGIC: return "configfs"; + case STATFS_CRAMFS_MAGIC: return "cramfs"; + case STATFS_DEBUGFS_MAGIC: return "debugfs"; + case STATFS_DEVPTS_MAGIC: return "devpts"; + case STATFS_ECRYPTFS_MAGIC: return "ecryptfs"; + case STATFS_EFIVARFS_MAGIC: return "efivarfs"; + case STATFS_EFS_MAGIC: return "efs"; + case STATFS_EXOFS_MAGIC: return "exofs"; + case STATFS_EXT4_MAGIC: return "ext4"; /* all extN use the same magic */ + case STATFS_F2FS_MAGIC: return "f2fs"; + case STATFS_FUSE_MAGIC: return "fuse"; + case STATFS_FUTEXFS_MAGIC: return "futexfs"; + case STATFS_GFS2_MAGIC: return "gfs2"; + case STATFS_HFSPLUS_MAGIC: return "hfsplus"; + case STATFS_HOSTFS_MAGIC: return "hostfs"; + case STATFS_HPFS_MAGIC: return "hpfs"; + case STATFS_HPPFS_MAGIC: return "hppfs"; + case STATFS_HUGETLBFS_MAGIC: return "hugetlbfs"; + case STATFS_ISOFS_MAGIC: return "iso9660"; + case STATFS_JFFS2_MAGIC: return "jffs2"; + case STATFS_JFS_MAGIC: return "jfs"; + case STATFS_LOGFS_MAGIC: return "logfs"; + case STATFS_MINIX2_MAGIC: + case STATFS_MINIX2_MAGIC2: + case STATFS_MINIX3_MAGIC: + case STATFS_MINIX_MAGIC: + case STATFS_MINIX_MAGIC2: return "minix"; + case STATFS_MQUEUE_MAGIC: return "mqueue"; + case STATFS_MSDOS_MAGIC: return "vfat"; + case STATFS_NCP_MAGIC: return "ncp"; + case STATFS_NFS_MAGIC: return "nfs"; + case STATFS_NILFS_MAGIC: return "nilfs2"; + case STATFS_NTFS_MAGIC: return "ntfs"; + case STATFS_OCFS2_MAGIC: return "ocfs2"; + case STATFS_OMFS_MAGIC: return "omfs"; + case STATFS_OPENPROMFS_MAGIC: return "openpromfs"; + case STATFS_PIPEFS_MAGIC: return "pipefs"; + case STATFS_PROC_MAGIC: return "proc"; + case STATFS_PSTOREFS_MAGIC: return "pstore"; + case STATFS_QNX4_MAGIC: return "qnx4"; + case STATFS_QNX6_MAGIC: return "qnx6"; + case STATFS_RAMFS_MAGIC: return "ramfs"; + case STATFS_REISERFS_MAGIC: return "reiser4"; + case STATFS_ROMFS_MAGIC: return "romfs"; + case STATFS_SECURITYFS_MAGIC: return "securityfs"; + case STATFS_SELINUXFS_MAGIC: return "selinuxfs"; + case STATFS_SMACKFS_MAGIC: return "smackfs"; + case STATFS_SMB_MAGIC: return "smb"; + case STATFS_SOCKFS_MAGIC: return "sockfs"; + case STATFS_SQUASHFS_MAGIC: return "squashfs"; + case STATFS_SYSFS_MAGIC: return "sysfs"; + case STATFS_TMPFS_MAGIC: return "tmpfs"; + case STATFS_UBIFS_MAGIC: return "ubifs"; + case STATFS_UDF_MAGIC: return "udf"; + case STATFS_UFS2_MAGIC: + case STATFS_UFS_MAGIC: return "ufs"; + case STATFS_V9FS_MAGIC: return "9p"; + case STATFS_VXFS_MAGIC: return "vxfs"; + case STATFS_XENFS_MAGIC: return "xenfs"; + case STATFS_XFS_MAGIC: return "xfs"; + default: + break; + } + + return NULL; +} + + +/** + * mnt_match_fstype: + * @type: filesystem type + * @pattern: filesystem name or comma delimited list of names + * + * The @pattern list of filesystems 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); +} + +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); + (*filesystems)[n] = name; + (*filesystems)[n + 1] = NULL; + if (!name) + goto err; + 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[129]; + + f = fopen(filename, "r" UL_CLOEXECSTR); + if (!f) + return 1; + + DBG(UTILS, ul_debug("reading filesystems list from: %s", filename)); + + 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 (strcmp(name, "*") == 0) { + rc = 1; + break; /* end of the /etc/filesystems */ + } + if (pattern && !mnt_match_fstype(name, pattern)) + continue; + rc = add_filesystem(filesystems, name); + if (rc) + break; + } + + fclose(f); + return rc; +} + +/* + * Always check the @filesystems pointer! + * + * man mount: + * + * ...mount will try to read the file /etc/filesystems, or, if that does not + * exist, /proc/filesystems. All of the filesystem types listed there will + * be tried, except for those that are labeled "nodev" (e.g., devpts, + * proc and nfs). If /etc/filesystems ends in a line with a single * only, + * mount will read /proc/filesystems afterwards. + */ +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 != 1) + return rc; + + rc = get_filesystems(_PATH_PROC_FILESYSTEMS, filesystems, pattern); + if (rc == 1 && *filesystems) + rc = 0; /* /proc/filesystems not found */ + + return rc; +} + +/* + * Returns an allocated string with username or NULL. + */ +char *mnt_get_username(const uid_t uid) +{ + struct passwd pwd; + struct passwd *res; + char *buf, *username = NULL; + + buf = malloc(UL_GETPW_BUFSIZ); + if (!buf) + return NULL; + + if (!getpwuid_r(uid, &pwd, buf, UL_GETPW_BUFSIZ, &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; + char *buf; + + if (!username || !uid) + return -EINVAL; + + buf = malloc(UL_GETPW_BUFSIZ); + if (!buf) + return -ENOMEM; + + if (!getpwnam_r(username, &pwd, buf, UL_GETPW_BUFSIZ, &pw) && pw) { + *uid= pw->pw_uid; + rc = 0; + } else { + DBG(UTILS, ul_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; + char *buf; + + if (!groupname || !gid) + return -EINVAL; + + buf = malloc(UL_GETPW_BUFSIZ); + if (!buf) + return -ENOMEM; + + if (!getgrnam_r(groupname, &grp, buf, UL_GETPW_BUFSIZ, &gr) && gr) { + *gid= gr->gr_gid; + rc = 0; + } else { + DBG(UTILS, ul_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, const char *directory) +{ + int rc = 0; + + if (!filename) + return -EINVAL; + + DBG(UTILS, ul_debug("try write %s dir: %s", filename, directory)); + +#ifdef HAVE_EACCESS + /* Try eaccess() first, because open() is overkill, may be monitored by + * audit and we don't want to fill logs by our checks... + */ + if (eaccess(filename, R_OK|W_OK) == 0) { + DBG(UTILS, ul_debug(" access OK")); + return 0; + } else if (errno != ENOENT) { + DBG(UTILS, ul_debug(" access FAILED")); + return -errno; + } else if (directory) { + /* file does not exist; try if directory is writable */ + if (eaccess(directory, R_OK|W_OK) != 0) + rc = -errno; + + DBG(UTILS, ul_debug(" access %s [%s]", rc ? "FAILED" : "OK", directory)); + return rc; + } else +#endif + { + DBG(UTILS, ul_debug(" doing open-write test")); + + int fd = open(filename, O_RDWR|O_CREAT|O_CLOEXEC, + S_IWUSR|S_IRUSR|S_IRGRP|S_IROTH); + if (fd < 0) + rc = -errno; + else + close(fd); + } + return rc; +} + +/** + * 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, ul_debug("mtab: %s", filename)); + + rc = lstat(filename, &st); + + if (rc == 0) { + /* file exists */ + if (S_ISREG(st.st_mode)) { + if (writable) + *writable = !try_write(filename, NULL); + DBG(UTILS, ul_debug("%s: writable", filename)); + return 1; + } + goto done; + } + + /* try to create the file */ + if (writable) { + *writable = !try_write(filename, NULL); + if (*writable) { + DBG(UTILS, ul_debug("%s: writable", filename)); + return 1; + } + } + +done: + DBG(UTILS, ul_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, ul_debug("utab: %s", filename)); + + rc = lstat(filename, &st); + + if (rc == 0) { + /* file exists */ + if (S_ISREG(st.st_mode)) { + if (writable) + *writable = !try_write(filename, NULL); + return 1; + } + goto done; /* it's not a 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); + if (rc && errno != EEXIST) { + free(dirname); + goto done; /* probably EACCES */ + } + + *writable = !try_write(filename, dirname); + free(dirname); + if (*writable) + return 1; + } +done: + DBG(UTILS, ul_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 the *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 a unique filename + */ +int mnt_open_uniq_filename(const char *filename, char **name) +{ + int rc, fd; + char *n; + mode_t oldmode; + + if (!filename) + return -EINVAL; + if (name) + *name = NULL; + + rc = asprintf(&n, "%s.XXXXXX", filename); + if (rc <= 0) + return -errno; + + /* This is for very old glibc and for compatibility with Posix, which says + * nothing about mkstemp() mode. All sane glibc use secure mode (0600). + */ + oldmode = umask(S_IRGRP|S_IWGRP|S_IXGRP| + S_IROTH|S_IWOTH|S_IXOTH); + fd = mkostemp(n, O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC); + if (fd < 0) + fd = -errno; + umask(oldmode); + + if (fd >= 0 && name) + *name = n; + else + free(n); + + return 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. + * + * WARNING: the function compares st_dev of the @path elements. This traditional + * way maybe be insufficient on filesystems like Linux "overlay". See also + * mnt_table_find_target(). + * + * Returns: allocated string with the target of the mounted device or NULL on error + */ +char *mnt_get_mountpoint(const char *path) +{ + char *mnt; + struct stat st; + dev_t dir, base; + + if (!path) + return NULL; + + mnt = strdup(path); + if (!mnt) + return NULL; + if (*mnt == '/' && *(mnt + 1) == '\0') + goto done; + + if (mnt_stat_mountpoint(mnt, &st)) + goto err; + base = st.st_dev; + + do { + char *p = stripoff_last_component(mnt); + + if (!p) + break; + if (mnt_stat_mountpoint(*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, ul_debug("%s mountpoint is %s", path, mnt)); + return mnt; +err: + free(mnt); + return NULL; +} + +/* + * Search for @name kernel command parameter. + * + * Returns newly allocated string with a parameter argument if the @name is + * specified as "name=" or returns pointer to @name or returns NULL if not + * found. If it is specified more than once, we grab the last copy. + * + * For example cmdline: "aaa bbb=BBB ccc" + * + * @name is "aaa" --returns--> "aaa" (pointer to @name) + * @name is "bbb=" --returns--> "BBB" (allocated) + * @name is "foo" --returns--> NULL + * + * Note: It is not really feasible to parse the command line exactly the same + * as the kernel does since we don't know which options are valid. We can use + * the -- marker though and not walk past that. + */ +char *mnt_get_kernel_cmdline_option(const char *name) +{ + FILE *f; + size_t len; + int val = 0; + char *p, *res = NULL, *mem = NULL; + char buf[BUFSIZ]; /* see kernel include/asm-generic/setup.h: COMMAND_LINE_SIZE */ + const char *path = _PATH_PROC_CMDLINE; + + if (!name || !name[0]) + return NULL; + +#ifdef TEST_PROGRAM + path = getenv("LIBMOUNT_KERNEL_CMDLINE"); + if (!path) + path = _PATH_PROC_CMDLINE; +#endif + f = fopen(path, "r" UL_CLOEXECSTR); + if (!f) + return NULL; + + p = fgets(buf, sizeof(buf), f); + fclose(f); + + if (!p || !*p || *p == '\n') + return NULL; + + p = strstr(p, " -- "); + if (p) { + /* no more kernel args after this */ + *p = '\0'; + } else { + len = strlen(buf); + buf[len - 1] = '\0'; /* remove last '\n' */ + } + + len = strlen(name); + if (name[len - 1] == '=') + val = 1; + + for (p = buf; p && *p; p++) { + if (!(p = strstr(p, name))) + break; /* not found the option */ + if (p != buf && !isblank(*(p - 1))) + continue; /* no space before the option */ + if (!val && *(p + len) != '\0' && !isblank(*(p + len))) + continue; /* no space after the option */ + if (val) { + char *v = p + len; + int end; + + while (*p && !isblank(*p)) /* jump to the end of the argument */ + p++; + end = (*p == '\0'); + *p = '\0'; + free(mem); + res = mem = strdup(v); + if (end) + break; + } else + res = (char *) name; /* option without '=' */ + /* don't break -- keep scanning for more options */ + } + + return res; +} + +/* + * Converts @devno to the real device name if devno major number is greater + * than zero, otherwise use root= kernel cmdline option to get device name. + * + * The function uses /sys to convert devno to device name. + * + * Returns: 0 = success, 1 = not found, <0 = error + */ +int mnt_guess_system_root(dev_t devno, struct libmnt_cache *cache, char **path) +{ + char buf[PATH_MAX]; + char *dev = NULL, *spec = NULL; + unsigned int x, y; + int allocated = 0; + + assert(path); + + DBG(UTILS, ul_debug("guessing system root [devno %u:%u]", major(devno), minor(devno))); + + /* The pseudo-fs, net-fs or btrfs devno is useless, otherwise it + * usually matches with the source device, let's try to use it. + */ + if (major(devno) > 0) { + dev = sysfs_devno_to_devpath(devno, buf, sizeof(buf)); + if (dev) { + DBG(UTILS, ul_debug(" devno converted to %s", dev)); + goto done; + } + } + + /* Let's try to use root= kernel command line option + */ + spec = mnt_get_kernel_cmdline_option("root="); + if (!spec) + goto done; + + /* maj:min notation */ + if (sscanf(spec, "%u:%u", &x, &y) == 2) { + dev = sysfs_devno_to_devpath(makedev(x, y), buf, sizeof(buf)); + if (dev) { + DBG(UTILS, ul_debug(" root=%s converted to %s", spec, dev)); + goto done; + } + + /* hexhex notation */ + } else if (isxdigit_string(spec)) { + char *end = NULL; + uint32_t n; + + errno = 0; + n = strtoul(spec, &end, 16); + + if (errno || spec == end || (end && *end)) + DBG(UTILS, ul_debug(" failed to parse root='%s'", spec)); + else { + /* kernel new_decode_dev() */ + x = (n & 0xfff00) >> 8; + y = (n & 0xff) | ((n >> 12) & 0xfff00); + dev = sysfs_devno_to_devpath(makedev(x, y), buf, sizeof(buf)); + if (dev) { + DBG(UTILS, ul_debug(" root=%s converted to %s", spec, dev)); + goto done; + } + } + + /* devname or PARTUUID= etc. */ + } else { + DBG(UTILS, ul_debug(" converting root='%s'", spec)); + + dev = mnt_resolve_spec(spec, cache); + if (dev && !cache) + allocated = 1; + } +done: + free(spec); + if (dev) { + *path = allocated ? dev : strdup(dev); + if (!*path) + return -ENOMEM; + return 0; + } + + return 1; +} + + +#ifdef TEST_PROGRAM +static 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; +} + +static 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; +} + +static 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; +} + +static 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; +} + +static int test_appendstr(struct libmnt_test *ts, int argc, char *argv[]) +{ + char *str = strdup(argv[1]); + const char *ap = argv[2]; + + append_string(&str, ap); + printf("new string: '%s'\n", str); + + free(str); + return 0; +} + +static 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; +} + +static 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; +} + +static 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; +} + +static int test_kernel_cmdline(struct libmnt_test *ts, int argc, char *argv[]) +{ + char *name = argv[1]; + char *res; + + res = mnt_get_kernel_cmdline_option(name); + if (!res) + printf("'%s' not found\n", name); + else if (res == name) + printf("'%s' found\n", name); + else { + printf("'%s' found, argument: '%s'\n", name, res); + free(res); + } + + return 0; +} + + +static int test_guess_root(struct libmnt_test *ts, int argc, char *argv[]) +{ + int rc; + char *real; + dev_t devno = 0; + + if (argc) { + unsigned int x, y; + + if (sscanf(argv[1], "%u:%u", &x, &y) != 2) + return -EINVAL; + devno = makedev(x, y); + } + + rc = mnt_guess_system_root(devno, NULL, &real); + if (rc < 0) + return rc; + if (rc == 1) + fputs("not found\n", stdout); + else { + printf("%s\n", real); + free(real); + } + return 0; +} + +static int test_mkdir(struct libmnt_test *ts, int argc, char *argv[]) +{ + int rc; + + rc = mkdir_p(argv[1], S_IRWXU | + S_IRGRP | S_IXGRP | + S_IROTH | S_IXOTH); + if (rc) + printf("mkdir %s failed\n", argv[1]); + return rc; +} + +static int test_statfs_type(struct libmnt_test *ts, int argc, char *argv[]) +{ + struct statfs vfs; + int rc; + + rc = statfs(argv[1], &vfs); + if (rc) + printf("%s: statfs failed: %m\n", argv[1]); + else + printf("%-30s: statfs type: %-12s [0x%lx]\n", argv[1], + mnt_statfs_get_fstype(&vfs), + (long) vfs.f_type); + 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>" }, + { "--append-string", test_appendstr, "<string> <appendix>" }, + { "--mountpoint", test_mountpoint, "<path>" }, + { "--cd-parent", test_chdir, "<path>" }, + { "--kernel-cmdline",test_kernel_cmdline, "<option> | <option>=" }, + { "--guess-root", test_guess_root, "[<maj:min>]" }, + { "--mkdir", test_mkdir, "<path>" }, + { "--statfs-type", test_statfs_type, "<path>" }, + + { NULL } + }; + + return mnt_run_test(tss, argc, argv); +} + +#endif /* TEST_PROGRAM */ |