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Systemd/src/shared/path-util.c
Lennart Poettering fabe5c0e5f binfmt,tmpfiles,modules-load,sysctl: rework the various early-boot services that work on .d/ directories 
This unifies much of the logic behind them:

- All four will now ofllow the rule that the earlier file and earlier
  assignment in the .d/ directories wins. Before, sysctl was the only
  outlier, where the later setting always won.

- All four now support getopt() and --help on the command line.

- All four can now handle specification of configuration file names on
  the command line to apply. The tools will automatically find them, and
  apply them. Previously only tmpfiles could do that. This is useful for
  %post scripts in RPMs and suchlike.

- This fixes various error path issues in conf_files_list()
2013-02-11 23:54:30 +01:00

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
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 <assert.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <fcntl.h>
#include <dirent.h>
#include <sys/statvfs.h>
#include "macro.h"
#include "util.h"
#include "log.h"
#include "strv.h"
#include "path-util.h"
#include "missing.h"
bool path_is_absolute(const char *p) {
return p[0] == '/';
}
bool is_path(const char *p) {
return !!strchr(p, '/');
}
char *path_get_file_name(const char *p) {
char *r;
assert(p);
if ((r = strrchr(p, '/')))
return r + 1;
return (char*) p;
}
int path_get_parent(const char *path, char **_r) {
const char *e, *a = NULL, *b = NULL, *p;
char *r;
bool slash = false;
assert(path);
assert(_r);
if (!*path)
return -EINVAL;
for (e = path; *e; e++) {
if (!slash && *e == '/') {
a = b;
b = e;
slash = true;
} else if (slash && *e != '/')
slash = false;
}
if (*(e-1) == '/')
p = a;
else
p = b;
if (!p)
return -EINVAL;
if (p == path)
r = strdup("/");
else
r = strndup(path, p-path);
if (!r)
return -ENOMEM;
*_r = r;
return 0;
}
char **path_split_and_make_absolute(const char *p) {
char **l;
assert(p);
if (!(l = strv_split(p, ":")))
return NULL;
if (!path_strv_make_absolute_cwd(l)) {
strv_free(l);
return NULL;
}
return l;
}
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);
}
char *path_make_absolute_cwd(const char *p) {
char *cwd, *r;
assert(p);
/* Similar to path_make_absolute(), but prefixes with the
* current working directory. */
if (path_is_absolute(p))
return strdup(p);
cwd = get_current_dir_name();
if (!cwd)
return NULL;
r = path_make_absolute(p, cwd);
free(cwd);
return r;
}
char **path_strv_make_absolute_cwd(char **l) {
char **s;
/* 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;
if (!(t = path_make_absolute_cwd(*s)))
return NULL;
free(*s);
*s = t;
}
return l;
}
char **path_strv_canonicalize(char **l) {
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;
t = path_make_absolute_cwd(*s);
free(*s);
*s = NULL;
if (!t) {
enomem = true;
continue;
}
errno = 0;
u = canonicalize_file_name(t);
if (!u) {
if (errno == ENOENT)
u = t;
else {
free(t);
if (errno == ENOMEM || !errno)
enomem = true;
continue;
}
} else
free(t);
l[k++] = u;
}
l[k] = NULL;
if (enomem)
return NULL;
return l;
}
char **path_strv_canonicalize_uniq(char **l) {
if (strv_isempty(l))
return l;
if (!path_strv_canonicalize(l))
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;
}
}
bool path_equal(const char *a, const char *b) {
assert(a);
assert(b);
if ((a[0] == '/') != (b[0] == '/'))
return false;
for (;;) {
size_t j, k;
a += strspn(a, "/");
b += strspn(b, "/");
if (*a == 0 && *b == 0)
return true;
if (*a == 0 || *b == 0)
return false;
j = strcspn(a, "/");
k = strcspn(b, "/");
if (j != k)
return false;
if (memcmp(a, b, j) != 0)
return false;
a += j;
b += k;
}
}
int path_is_mount_point(const char *t, bool allow_symlink) {
char *parent;
int r;
struct file_handle *h;
int mount_id, mount_id_parent;
struct stat a, b;
/* We are not actually interested in the file handles, but
* name_to_handle_at() also passes us the mount ID, hence use
* it but throw the handle away */
if (path_equal(t, "/"))
return 1;
h = alloca(MAX_HANDLE_SZ);
h->handle_bytes = MAX_HANDLE_SZ;
r = name_to_handle_at(AT_FDCWD, t, h, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0);
if (r < 0) {
if (errno == ENOSYS || errno == ENOTSUP)
/* This kernel or file system does not support
* name_to_handle_at(), hence fallback to the
* traditional stat() logic */
goto fallback;
if (errno == ENOENT)
return 0;
return -errno;
}
r = path_get_parent(t, &parent);
if (r < 0)
return r;
h->handle_bytes = MAX_HANDLE_SZ;
r = name_to_handle_at(AT_FDCWD, parent, h, &mount_id_parent, 0);
free(parent);
if (r < 0) {
/* The parent can't do name_to_handle_at() but the
* directory we are interested in can? If so, it must
* be a mount point */
if (errno == ENOTSUP)
return 1;
return -errno;
}
return mount_id != mount_id_parent;
fallback:
if (allow_symlink)
r = stat(t, &a);
else
r = lstat(t, &a);
if (r < 0) {
if (errno == ENOENT)
return 0;
return -errno;
}
r = path_get_parent(t, &parent);
if (r < 0)
return r;
r = lstat(parent, &b);
free(parent);
if (r < 0)
return -errno;
return a.st_dev != b.st_dev;
}
int path_is_read_only_fs(const char *path) {
struct statvfs st;
assert(path);
if (statvfs(path, &st) < 0)
return -errno;
return !!(st.f_flag & ST_RDONLY);
}
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