blob: 708da2e008b594161147046c97dfb9c58383a50b [file] [log] [blame]
/* 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 <poll.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",
"bpf",
"cgroup",
"cgroup2",
"configfs",
"cpuset",
"debugfs",
"devfs",
"devpts",
"devtmpfs",
"dlmfs",
"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",
"mqueue",
"nfsd",
"none",
"nsfs",
"overlay",
"pipefs",
"proc",
"pstore",
"ramfs",
"rootfs",
"rpc_pipefs",
"securityfs",
"selinuxfs",
"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 ||
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;
}
int is_procfs_fd(int fd)
{
struct statfs sfs;
return fstatfs(fd, &sfs) == 0 && sfs.f_type == STATFS_PROC_MAGIC;
}
/**
* 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 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_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;
}
/**
* 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;
}
#if defined(HAVE_FMEMOPEN) || defined(TEST_PROGRAM)
/*
* This function tries to minimize possible races when we read
* /proc/#/{mountinfo,mount} files.
*
* The idea is to minimize number of read()s and check by poll() that during
* the read the mount table has not been modified. If yes, than re-read it
* (with some limitations to avoid never ending loop).
*
* Returns: <0 error, 0 success, 1 too many attempts
*/
static int read_procfs_file(int fd, char **buf, size_t *bufsiz)
{
size_t bufmax = 0;
int rc = 0, tries = 0, ninters = 0;
char *bufptr = NULL;
assert(buf);
assert(bufsiz);
*bufsiz = 0;
*buf = NULL;
do {
ssize_t ret;
if (!bufptr || bufmax == *bufsiz) {
char *tmp;
bufmax = bufmax ? bufmax * 2 : (16 * 1024);
tmp = realloc(*buf, bufmax);
if (!tmp)
break;
*buf = tmp;
bufptr = tmp + *bufsiz;
}
errno = 0;
ret = read(fd, bufptr, bufmax - *bufsiz);
if (ret < 0) {
/* error */
if ((errno == EAGAIN || errno == EINTR) && (ninters++ < 5)) {
xusleep(200000);
continue;
}
break;
} else if (ret > 0) {
/* success -- verify no event during read */
struct pollfd fds[] = {
{ .fd = fd, .events = POLLPRI }
};
rc = poll(fds, 1, 0);
if (rc < 0)
break; /* poll() error */
if (rc > 0) {
/* event -- read all again */
if (lseek(fd, 0, SEEK_SET) != 0)
break;
*bufsiz = 0;
bufptr = *buf;
tries++;
if (tries > 10)
/* busy system? -- wait */
xusleep(10000);
continue;
}
/* successful read() without active poll() */
(*bufsiz) += (size_t) ret;
bufptr += ret;
tries = ninters = 0;
} else {
/* end-of-file */
goto success;
}
} while (tries <= 100);
rc = errno ? -errno : 1;
free(*buf);
return rc;
success:
return 0;
}
/*
* Create FILE stream for data from read_procfs_file()
*/
FILE *mnt_get_procfs_memstream(int fd, char **membuf)
{
size_t sz = 0;
off_t cur;
*membuf = NULL;
/* in case of error, rewind to the original position */
cur = lseek(fd, 0, SEEK_CUR);
if (read_procfs_file(fd, membuf, &sz) == 0 && sz > 0) {
FILE *memf = fmemopen(*membuf, sz, "r");
if (memf)
return memf; /* success */
free(*membuf);
*membuf = NULL;
}
/* error */
if (cur != (off_t) -1)
lseek(fd, cur, SEEK_SET);
return NULL;
}
#else
FILE *mnt_get_procfs_memstream(int fd __attribute((__unused__)),
char **membuf __attribute((__unused__)))
{
return NULL;
}
#endif /* HAVE_FMEMOPEN */
#ifdef TEST_PROGRAM
static int test_proc_read(struct libmnt_test *ts, int argc, char *argv[])
{
char *buf = NULL;
char *filename = argv[1];
size_t bufsiz = 0;
int rc = 0, fd = open(filename, O_RDONLY);
if (fd <= 0) {
warn("%s: cannot open", filename);
return -errno;
}
rc = read_procfs_file(fd, &buf, &bufsiz);
close(fd);
switch (rc) {
case 0:
fwrite(buf, 1, bufsiz, stdout);
free(buf);
break;
case 1:
warnx("too many attempts");
break;
default:
warn("%s: cannot read", filename);
break;
}
return rc;
}
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>" },
{ "--read-procfs", test_proc_read, "<path>" },
{ NULL }
};
return mnt_run_test(tss, argc, argv);
}
#endif /* TEST_PROGRAM */