/***
This file is part of systemd.
Copyright 2010-2012 Lennart Poettering
systemd 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.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
/* When we include libgen.h because we need dirname() we immediately
* undefine basename() since libgen.h defines it as a macro to the
* POSIX version which is really broken. We prefer GNU basename(). */
#include <libgen.h>
#undef basename
#include "alloc-util.h"
#include "extract-word.h"
#include "fs-util.h"
#include "log.h"
#include "macro.h"
#include "missing.h"
#include "path-util.h"
#include "stat-util.h"
#include "string-util.h"
#include "strv.h"
#include "time-util.h"
bool path_is_absolute(const char *p) {
return p[0] == '/';
}
bool is_path(const char *p) {
return !!strchr(p, '/');
}
int path_split_and_make_absolute(const char *p, char ***ret) {
char **l;
int r;
assert(p);
assert(ret);
l = strv_split(p, ":");
if (!l)
return -ENOMEM;
r = path_strv_make_absolute_cwd(l);
if (r < 0) {
strv_free(l);
return r;
}
*ret = l;
return r;
}
char *path_make_absolute(const char *p, const char *prefix) {
assert(p);
/* Makes every item in the list an absolute path by prepending
* the prefix, if specified and necessary */
if (path_is_absolute(p) || !prefix)
return strdup(p);
return strjoin(prefix, "/", p, NULL);
}
int path_make_absolute_cwd(const char *p, char **ret) {
char *c;
assert(p);
assert(ret);
/* Similar to path_make_absolute(), but prefixes with the
* current working directory. */
if (path_is_absolute(p))
c = strdup(p);
else {
_cleanup_free_ char *cwd = NULL;
cwd = get_current_dir_name();
if (!cwd)
return negative_errno();
c = strjoin(cwd, "/", p, NULL);
}
if (!c)
return -ENOMEM;
*ret = c;
return 0;
}
int path_make_relative(const char *from_dir, const char *to_path, char **_r) {
char *r, *p;
unsigned n_parents;
assert(from_dir);
assert(to_path);
assert(_r);
/* Strips the common part, and adds ".." elements as necessary. */
if (!path_is_absolute(from_dir))
return -EINVAL;
if (!path_is_absolute(to_path))
return -EINVAL;
/* Skip the common part. */
for (;;) {
size_t a;
size_t b;
from_dir += strspn(from_dir, "/");
to_path += strspn(to_path, "/");
if (!*from_dir) {
if (!*to_path)
/* from_dir equals to_path. */
r = strdup(".");
else
/* from_dir is a parent directory of to_path. */
r = strdup(to_path);
if (!r)
return -ENOMEM;
path_kill_slashes(r);
*_r = r;
return 0;
}
if (!*to_path)
break;
a = strcspn(from_dir, "/");
b = strcspn(to_path, "/");
if (a != b)
break;
if (memcmp(from_dir, to_path, a) != 0)
break;
from_dir += a;
to_path += b;
}
/* If we're here, then "from_dir" has one or more elements that need to
* be replaced with "..". */
/* Count the number of necessary ".." elements. */
for (n_parents = 0;;) {
from_dir += strspn(from_dir, "/");
if (!*from_dir)
break;
from_dir += strcspn(from_dir, "/");
n_parents++;
}
r = malloc(n_parents * 3 + strlen(to_path) + 1);
if (!r)
return -ENOMEM;
for (p = r; n_parents > 0; n_parents--, p += 3)
memcpy(p, "../", 3);
strcpy(p, to_path);
path_kill_slashes(r);
*_r = r;
return 0;
}
int path_strv_make_absolute_cwd(char **l) {
char **s;
int r;
/* Goes through every item in the string list and makes it
* absolute. This works in place and won't rollback any
* changes on failure. */
STRV_FOREACH(s, l) {
char *t;
r = path_make_absolute_cwd(*s, &t);
if (r < 0)
return r;
free(*s);
*s = t;
}
return 0;
}
char **path_strv_resolve(char **l, const char *prefix) {
char **s;
unsigned k = 0;
bool enomem = false;
if (strv_isempty(l))
return l;
/* Goes through every item in the string list and canonicalize
* the path. This works in place and won't rollback any
* changes on failure. */
STRV_FOREACH(s, l) {
char *t, *u;
_cleanup_free_ char *orig = NULL;
if (!path_is_absolute(*s)) {
free(*s);
continue;
}
if (prefix) {
orig = *s;
t = strappend(prefix, orig);
if (!t) {
enomem = true;
continue;
}
} else
t = *s;
errno = 0;
u = canonicalize_file_name(t);
if (!u) {
if (errno == ENOENT) {
if (prefix) {
u = orig;
orig = NULL;
free(t);
} else
u = t;
} else {
free(t);
if (errno == ENOMEM || errno == 0)
enomem = true;
continue;
}
} else if (prefix) {
char *x;
free(t);
x = path_startswith(u, prefix);
if (x) {
/* restore the slash if it was lost */
if (!startswith(x, "/"))
*(--x) = '/';
t = strdup(x);
free(u);
if (!t) {
enomem = true;
continue;
}
u = t;
} else {
/* canonicalized path goes outside of
* prefix, keep the original path instead */
free(u);
u = orig;
orig = NULL;
}
} else
free(t);
l[k++] = u;
}
l[k] = NULL;
if (enomem)
return NULL;
return l;
}
char **path_strv_resolve_uniq(char **l, const char *prefix) {
if (strv_isempty(l))
return l;
if (!path_strv_resolve(l, prefix))
return NULL;
return strv_uniq(l);
}
char *path_kill_slashes(char *path) {
char *f, *t;
bool slash = false;
/* Removes redundant inner and trailing slashes. Modifies the
* passed string in-place.
*
* ///foo///bar/ becomes /foo/bar
*/
for (f = path, t = path; *f; f++) {
if (*f == '/') {
slash = true;
continue;
}
if (slash) {
slash = false;
*(t++) = '/';
}
*(t++) = *f;
}
/* Special rule, if we are talking of the root directory, a
trailing slash is good */
if (t == path && slash)
*(t++) = '/';
*t = 0;
return path;
}
char* path_startswith(const char *path, const char *prefix) {
assert(path);
assert(prefix);
if ((path[0] == '/') != (prefix[0] == '/'))
return NULL;
for (;;) {
size_t a, b;
path += strspn(path, "/");
prefix += strspn(prefix, "/");
if (*prefix == 0)
return (char*) path;
if (*path == 0)
return NULL;
a = strcspn(path, "/");
b = strcspn(prefix, "/");
if (a != b)
return NULL;
if (memcmp(path, prefix, a) != 0)
return NULL;
path += a;
prefix += b;
}
}
int path_compare(const char *a, const char *b) {
int d;
assert(a);
assert(b);
/* A relative path and an abolute path must not compare as equal.
* Which one is sorted before the other does not really matter.
* Here a relative path is ordered before an absolute path. */
d = (a[0] == '/') - (b[0] == '/');
if (d != 0)
return d;
for (;;) {
size_t j, k;
a += strspn(a, "/");
b += strspn(b, "/");
if (*a == 0 && *b == 0)
return 0;
/* Order prefixes first: "/foo" before "/foo/bar" */
if (*a == 0)
return -1;
if (*b == 0)
return 1;
j = strcspn(a, "/");
k = strcspn(b, "/");
/* Alphabetical sort: "/foo/aaa" before "/foo/b" */
d = memcmp(a, b, MIN(j, k));
if (d != 0)
return (d > 0) - (d < 0); /* sign of d */
/* Sort "/foo/a" before "/foo/aaa" */
d = (j > k) - (j < k); /* sign of (j - k) */
if (d != 0)
return d;
a += j;
b += k;
}
}
bool path_equal(const char *a, const char *b) {
return path_compare(a, b) == 0;
}
bool path_equal_or_files_same(const char *a, const char *b) {
return path_equal(a, b) || files_same(a, b) > 0;
}
char* path_join(const char *root, const char *path, const char *rest) {
assert(path);
if (!isempty(root))
return strjoin(root, endswith(root, "/") ? "" : "/",
path[0] == '/' ? path+1 : path,
rest ? (endswith(path, "/") ? "" : "/") : NULL,
rest && rest[0] == '/' ? rest+1 : rest,
NULL);
else
return strjoin(path,
rest ? (endswith(path, "/") ? "" : "/") : NULL,
rest && rest[0] == '/' ? rest+1 : rest,
NULL);
}
int find_binary(const char *name, char **ret) {
int last_error, r;
const char *p;
assert(name);
if (is_path(name)) {
if (access(name, X_OK) < 0)
return -errno;
if (ret) {
r = path_make_absolute_cwd(name, ret);
if (r < 0)
return r;
}
return 0;
}
/**
* Plain getenv, not secure_getenv, because we want
* to actually allow the user to pick the binary.
*/
p = getenv("PATH");
if (!p)
p = DEFAULT_PATH;
last_error = -ENOENT;
for (;;) {
_cleanup_free_ char *j = NULL, *element = NULL;
r = extract_first_word(&p, &element, ":", EXTRACT_RELAX|EXTRACT_DONT_COALESCE_SEPARATORS);
if (r < 0)
return r;
if (r == 0)
break;
if (!path_is_absolute(element))
continue;
j = strjoin(element, "/", name, NULL);
if (!j)
return -ENOMEM;
if (access(j, X_OK) >= 0) {
/* Found it! */
if (ret) {
*ret = path_kill_slashes(j);
j = NULL;
}
return 0;
}
last_error = -errno;
}
return last_error;
}
bool paths_check_timestamp(const char* const* paths, usec_t *timestamp, bool update) {
bool changed = false;
const char* const* i;
assert(timestamp);
if (paths == NULL)
return false;
STRV_FOREACH(i, paths) {
struct stat stats;
usec_t u;
if (stat(*i, &stats) < 0)
continue;
u = timespec_load(&stats.st_mtim);
/* first check */
if (*timestamp >= u)
continue;
log_debug("timestamp of '%s' changed", *i);
/* update timestamp */
if (update) {
*timestamp = u;
changed = true;
} else
return true;
}
return changed;
}
static int binary_is_good(const char *binary) {
_cleanup_free_ char *p = NULL, *d = NULL;
int r;
r = find_binary(binary, &p);
if (r == -ENOENT)
return 0;
if (r < 0)
return r;
/* An fsck that is linked to /bin/true is a non-existent
* fsck */
r = readlink_malloc(p, &d);
if (r == -EINVAL) /* not a symlink */
return 1;
if (r < 0)
return r;
return !path_equal(d, "true") &&
!path_equal(d, "/bin/true") &&
!path_equal(d, "/usr/bin/true") &&
!path_equal(d, "/dev/null");
}
int fsck_exists(const char *fstype) {
const char *checker;
assert(fstype);
if (streq(fstype, "auto"))
return -EINVAL;
checker = strjoina("fsck.", fstype);
return binary_is_good(checker);
}
int mkfs_exists(const char *fstype) {
const char *mkfs;
assert(fstype);
if (streq(fstype, "auto"))
return -EINVAL;
mkfs = strjoina("mkfs.", fstype);
return binary_is_good(mkfs);
}
char *prefix_root(const char *root, const char *path) {
char *n, *p;
size_t l;
/* If root is passed, prefixes path with it. Otherwise returns
* it as is. */
assert(path);
/* First, drop duplicate prefixing slashes from the path */
while (path[0] == '/' && path[1] == '/')
path++;
if (isempty(root) || path_equal(root, "/"))
return strdup(path);
l = strlen(root) + 1 + strlen(path) + 1;
n = new(char, l);
if (!n)
return NULL;
p = stpcpy(n, root);
while (p > n && p[-1] == '/')
p--;
if (path[0] != '/')
*(p++) = '/';
strcpy(p, path);
return n;
}
int parse_path_argument_and_warn(const char *path, bool suppress_root, char **arg) {
char *p;
int r;
/*
* This function is intended to be used in command line
* parsers, to handle paths that are passed in. It makes the
* path absolute, and reduces it to NULL if omitted or
* root (the latter optionally).
*
* NOTE THAT THIS WILL FREE THE PREVIOUS ARGUMENT POINTER ON
* SUCCESS! Hence, do not pass in uninitialized pointers.
*/
if (isempty(path)) {
*arg = mfree(*arg);
return 0;
}
r = path_make_absolute_cwd(path, &p);
if (r < 0)
return log_error_errno(r, "Failed to parse path \"%s\" and make it absolute: %m", path);
path_kill_slashes(p);
if (suppress_root && path_equal(p, "/"))
p = mfree(p);
free(*arg);
*arg = p;
return 0;
}
char* dirname_malloc(const char *path) {
char *d, *dir, *dir2;
assert(path);
d = strdup(path);
if (!d)
return NULL;
dir = dirname(d);
assert(dir);
if (dir == d)
return d;
dir2 = strdup(dir);
free(d);
return dir2;
}
bool filename_is_valid(const char *p) {
const char *e;
if (isempty(p))
return false;
if (streq(p, "."))
return false;
if (streq(p, ".."))
return false;
e = strchrnul(p, '/');
if (*e != 0)
return false;
if (e - p > FILENAME_MAX)
return false;
return true;
}
bool path_is_safe(const char *p) {
if (isempty(p))
return false;
if (streq(p, "..") || startswith(p, "../") || endswith(p, "/..") || strstr(p, "/../"))
return false;
if (strlen(p)+1 > PATH_MAX)
return false;
/* The following two checks are not really dangerous, but hey, they still are confusing */
if (streq(p, ".") || startswith(p, "./") || endswith(p, "/.") || strstr(p, "/./"))
return false;
if (strstr(p, "//"))
return false;
return true;
}
char *file_in_same_dir(const char *path, const char *filename) {
char *e, *ret;
size_t k;
assert(path);
assert(filename);
/* This removes the last component of path and appends
* filename, unless the latter is absolute anyway or the
* former isn't */
if (path_is_absolute(filename))
return strdup(filename);
e = strrchr(path, '/');
if (!e)
return strdup(filename);
k = strlen(filename);
ret = new(char, (e + 1 - path) + k + 1);
if (!ret)
return NULL;
memcpy(mempcpy(ret, path, e + 1 - path), filename, k + 1);
return ret;
}
bool hidden_file_allow_backup(const char *filename) {
assert(filename);
return
filename[0] == '.' ||
streq(filename, "lost+found") ||
streq(filename, "aquota.user") ||
streq(filename, "aquota.group") ||
endswith(filename, ".rpmnew") ||
endswith(filename, ".rpmsave") ||
endswith(filename, ".rpmorig") ||
endswith(filename, ".dpkg-old") ||
endswith(filename, ".dpkg-new") ||
endswith(filename, ".dpkg-tmp") ||
endswith(filename, ".dpkg-dist") ||
endswith(filename, ".dpkg-bak") ||
endswith(filename, ".dpkg-backup") ||
endswith(filename, ".dpkg-remove") ||
endswith(filename, ".swp");
}
bool hidden_file(const char *filename) {
assert(filename);
if (endswith(filename, "~"))
return true;
return hidden_file_allow_backup(filename);
}
bool is_device_path(const char *path) {
/* Returns true on paths that refer to a device, either in
* sysfs or in /dev */
return
path_startswith(path, "/dev/") ||
path_startswith(path, "/sys/");
}