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v2.40
libmount/src/utils.c
1 601 строка
35 KB
Karel Zak
libmount: don't assume errno after failed asprintf()
08 янв 2024, 12:32
08 янв 2024, 12:32
a002df0
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/* 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" #include "namespace.h" /* * 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("ID", tagname) == 0 || 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); } /* This very simplified stat() alternative uses cached VFS data and does not * directly ask the filesystem for details. It requires a kernel that supports * statx(). It's usable only for file type, rdev and ino! */ static int safe_stat(const char *target, struct stat *st, int nofollow) { assert(target); assert(st); memset(st, 0, sizeof(struct stat)); #if defined(HAVE_STATX) && defined(HAVE_STRUCT_STATX) && defined(AT_STATX_DONT_SYNC) { int rc; struct statx stx = { 0 }; rc = statx(AT_FDCWD, target, /* flags */ AT_STATX_DONT_SYNC | AT_NO_AUTOMOUNT | (nofollow ? AT_SYMLINK_NOFOLLOW : 0), /* mask */ STATX_TYPE | STATX_MODE | STATX_INO, &stx); if (rc == 0) { st->st_ino = stx.stx_ino; st->st_dev = makedev(stx.stx_dev_major, stx.stx_dev_minor); st->st_rdev = makedev(stx.stx_rdev_major, stx.stx_rdev_minor); st->st_mode = stx.stx_mode; } if (rc == 0 || (errno != EOPNOTSUPP && errno != ENOSYS && errno != EINVAL)) return rc; } #endif #ifdef AT_NO_AUTOMOUNT return fstatat(AT_FDCWD, target, st, AT_NO_AUTOMOUNT | (nofollow ? AT_SYMLINK_NOFOLLOW : 0)); #endif return nofollow ? lstat(target, st) : stat(target, st); } int mnt_safe_stat(const char *target, struct stat *st) { return safe_stat(target, st, 0); } int mnt_safe_lstat(const char *target, struct stat *st) { return safe_stat(target, st, 1); } /* Don't use access() or stat() here, we need a way how to check the path * without trigger an automount or hangs on NFS, etc. */ int mnt_is_path(const char *target) { struct stat st; return safe_stat(target, &st, 0) == 0; } /* * 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", "apparmorfs", "autofs", "bdev", "binder", "binfmt_misc", "bpf", "cgroup", "cgroup2", "configfs", "cpuset", "debugfs", "devfs", "devpts", "devtmpfs", "dlmfs", "dmabuf", "drm", "efivarfs", "fuse", /* Fallback name of fuse used by many poorly written drivers. */ "fuse.archivemount", /* Not a true pseudofs (has source), but source is not reported. */ "fuse.avfsd", /* Not a true pseudofs (has source), but source is not reported. */ "fuse.dumpfs", /* In fact, it is a netfs, but source is not reported. */ "fuse.encfs", /* Not a true pseudofs (has source), but source is not reported. */ "fuse.gvfs-fuse-daemon", /* Old name, not used by gvfs any more. */ "fuse.gvfsd-fuse", "fuse.lxcfs", "fuse.rofiles-fuse", "fuse.vmware-vmblock", "fuse.xwmfs", "fusectl", "hugetlbfs", "ipathfs", "mqueue", "nfsd", "none", "nsfs", "overlay", "pipefs", "proc", "pstore", "ramfs", "resctrl", "rootfs", "rpc_pipefs", "securityfs", "selinuxfs", "smackfs", "sockfs", "spufs", "sysfs", "tmpfs", "tracefs", "vboxsf", "virtiofs" }; 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, "smb3") == 0 || strcmp(type, "smbfs") == 0 || strncmp(type,"nfs", 3) == 0 || strcmp(type, "afs") == 0 || strcmp(type, "ncpfs") == 0 || strcmp(type, "glusterfs") == 0 || strcmp(type, "fuse.curlftpfs") == 0 || strcmp(type, "fuse.sshfs") == 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 = reallocarray(*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)); if (errno == 0) errno = EINVAL; rc = -errno;; } 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)); if (errno == 0) errno = EINVAL; rc = -errno;; } free(buf); return rc; } static int parse_uid_numeric(const char *value, uid_t *uid) { uint64_t num; int rc; assert(value); assert(uid); rc = ul_strtou64(value, &num, 10); if (rc != 0) goto fail; if (num > ULONG_MAX || (uid_t) num != num) { rc = -(errno = ERANGE); goto fail; } *uid = (uid_t) num; return 0; fail: DBG(UTILS, ul_debug("failed to convert '%s' to number [rc=%d, errno=%d]", value, rc, errno)); return rc; } /* Parse user_len-sized user; returns <0 on error, or 0 on success */ int mnt_parse_uid(const char *user, size_t user_len, uid_t *uid) { char *user_tofree = NULL; int rc; assert(user); assert(user_len); assert(uid); if (user[user_len] != '\0') { user = user_tofree = strndup(user, user_len); if (!user) return -ENOMEM; } rc = mnt_get_uid(user, uid); if (rc != 0 && isdigit(*user)) rc = parse_uid_numeric(user, uid); free(user_tofree); return rc; } static int parse_gid_numeric(const char *value, gid_t *gid) { uint64_t num; int rc; assert(value); assert(gid); rc = ul_strtou64(value, &num, 10); if (rc != 0) goto fail; if (num > ULONG_MAX || (gid_t) num != num) { rc = -(errno = ERANGE); goto fail; } *gid = (gid_t) num; return 0; fail: DBG(UTILS, ul_debug("failed to convert '%s' to number [rc=%d, errno=%d]", value, rc, errno)); return rc; } /* POSIX-parse group_len-sized group; -1 and errno set, or 0 on success */ int mnt_parse_gid(const char *group, size_t group_len, gid_t *gid) { char *group_tofree = NULL; int rc; assert(group); assert(group_len); assert(gid); if (group[group_len] != '\0') { group = group_tofree = strndup(group, group_len); if (!group) return -ENOMEM; } rc = mnt_get_gid(group, gid); if (rc != 0 && isdigit(*group)) rc = parse_gid_numeric(group, gid); free(group_tofree); return rc; } int mnt_parse_mode(const char *mode, size_t mode_len, mode_t *uid) { char buf[sizeof(stringify_value(UINT32_MAX))]; uint32_t num; int rc; assert(mode); assert(mode_len); assert(uid); if (mode_len > sizeof(buf) - 1) { rc = -(errno = ERANGE); goto fail; } mem2strcpy(buf, mode, mode_len, sizeof(buf)); rc = ul_strtou32(buf, &num, 8); if (rc != 0) goto fail; if (num > 07777) { rc = -(errno = ERANGE); goto fail; } *uid = (mode_t) num; return 0; fail: DBG(UTILS, ul_debug("failed to convert '%.*s' to mode [rc=%d, errno=%d]", (int) mode_len, mode, rc, errno)); 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; } if (errno != ENOENT) { DBG(UTILS, ul_debug(" access FAILED")); return -errno; } 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; } #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 NULL * @writable: returns 0 * * Returns: 0 * * Deprecated: libmount does not use /etc/mtab at all since v2.39. */ int mnt_has_regular_mtab(const char **mtab, int *writable) { if (writable) *writable = 0; if (mtab) *mtab = NULL; 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. * * * Returns: path to /etc/mtab or $LIBMOUNT_MTAB. * * Deprecated: libmount uses /proc/self/mountinfo only. * */ 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 $LIBMOUNT_UTAB. */ const char *mnt_get_utab_path(void) { const char *p = safe_getenv("LIBMOUNT_UTAB"); return p ? : MNT_PATH_UTAB; } /* 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 -ENOMEM; /* 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 = mkstemp_cloexec(n); 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 may 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_safe_stat(mnt, &st)) goto err; base = st.st_dev; do { char *p = stripoff_last_component(mnt); if (!p) break; if (mnt_safe_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, 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; if (!name || !name[0]) return NULL; #ifdef TEST_PROGRAM path = getenv("LIBMOUNT_KERNEL_CMDLINE"); if (!path) path = _PATH_PROC_CMDLINE; #else 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; } /** * mnt_guess_system_root: * @devno: device number or zero * @cache: paths cache or NULL * @path: returns allocated path * * 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 * * Since: 2.34 */ 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 __attribute__((unused)), int argc, char *argv[]) { if (argc != 3) return -1; 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 __attribute__((unused)), int argc, char *argv[]) { if (argc != 3) return -1; 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 __attribute__((unused)), int argc, char *argv[]) { if (argc != 3) return -1; 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 __attribute__((unused)), int argc, char *argv[]) { if (argc != 3) return -1; char *optstr = argv[1]; char *pattern = argv[2]; printf("%s\n", endswith(optstr, pattern) ? "YES" : "NOT"); return 0; } static int test_mountpoint(struct libmnt_test *ts __attribute__((unused)), int argc, char *argv[]) { if (argc != 2) return -1; 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 __attribute__((unused)), int argc, char *argv[]) { char **filesystems = NULL; int rc; if (argc != 1 && argc != 2) return -1; rc = mnt_get_filesystems(&filesystems, argc == 2 ? argv[1] : NULL); if (!rc && filesystems) { 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 __attribute__((unused)), int argc, char *argv[]) { if (argc != 2) return -1; 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 __attribute__((unused)), int argc, char *argv[]) { if (argc != 2) return -1; 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 __attribute__((unused)), 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 __attribute__((unused)), int argc, char *argv[]) { int rc; if (argc != 2) return -1; rc = ul_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 __attribute__((unused)), int argc, char *argv[]) { struct statfs vfs; int rc; if (argc != 2) return -1; 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; } static int tests_parse_uid(struct libmnt_test *ts __attribute__((unused)), int argc, char *argv[]) { if (argc != 2) return -1; char *str = argv[1]; uid_t uid = (uid_t) -1; int rc; rc = mnt_parse_uid(str, strlen(str), &uid); if (rc != 0) printf("failed: rc=%d: %m\n", rc); else printf("'%s' --> %lu\n", str, (unsigned long) uid); return rc; } static int tests_parse_gid(struct libmnt_test *ts __attribute__((unused)), int argc, char *argv[]) { if (argc != 2) return -1; char *str = argv[1]; gid_t gid = (gid_t) -1; int rc; rc = mnt_parse_gid(str, strlen(str), &gid); if (rc != 0) printf("failed: rc=%d: %m\n", rc); else printf("'%s' --> %lu\n", str, (unsigned long) gid); return rc; } static int tests_parse_mode(struct libmnt_test *ts __attribute__((unused)), int argc, char *argv[]) { if (argc != 2) return -1; char *str = argv[1]; mode_t mod = (mode_t) -1; int rc; rc = mnt_parse_mode(str, strlen(str), &mod); if (rc != 0) printf("failed: rc=%d: %m\n", rc); else { char modstr[11]; xstrmode(mod, modstr); printf("'%s' --> %04o [%s]\n", str, (unsigned int) mod, modstr); } return rc; } static int tests_stat(struct libmnt_test *ts __attribute__((unused)), int argc, char *argv[]) { if (argc != 2) return -1; char *path = argv[1]; struct stat st; int rc; if (strcmp(argv[0], "--lstat") == 0) rc = mnt_safe_lstat(path, &st); else rc = mnt_safe_stat(path, &st); if (rc) printf("%s: failed: rc=%d: %m\n", path, rc); else { printf("%s: \n", path); printf(" S_ISDIR: %s\n", S_ISDIR(st.st_mode) ? "y" : "n"); printf(" S_ISREG: %s\n", S_ISREG(st.st_mode) ? "y" : "n"); printf(" S_IFLNK: %s\n", S_ISLNK(st.st_mode) ? "y" : "n"); printf(" devno: %lu (%d:%d)\n", (unsigned long) st.st_dev, major(st.st_dev), minor(st.st_dev)); printf(" ino: %lu\n", (unsigned long) st.st_ino); } 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>" }, { "--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>" }, { "--parse-uid", tests_parse_uid, "<username|uid>" }, { "--parse-gid", tests_parse_gid, "<groupname|gid>" }, { "--parse-mode", tests_parse_mode, "<number>" }, { "--stat", tests_stat, "<path>" }, { "--lstat", tests_stat, "<path>" }, { NULL } }; return mnt_run_test(tss, argc, argv); } #endif /* TEST_PROGRAM */