/***
This file is part of eudev, forked from 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 .
***/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "macro.h"
#include "util.h"
#include "log.h"
#include "strv.h"
#include "mkdir.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, '/');
}
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_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) {
_cleanup_free_ char *cwd = NULL;
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;
return strjoin(cwd, "/", p, NULL);
}
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 = realpath(t, 0);
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)
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)
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)
return d;
a += j;
b += k;
}
}
bool path_equal(const char *a, const char *b) {
return path_compare(a, b) == 0;
}
int fd_is_mount_point(int fd) {
union file_handle_union h = FILE_HANDLE_INIT;
int mount_id = -1, mount_id_parent = -1;
bool nosupp = false;
struct stat a, b;
int r;
/* 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 */
r = name_to_handle_at(fd, "", &h.handle, &mount_id, AT_EMPTY_PATH);
if (r < 0) {
if (errno == ENOSYS)
/* This kernel does not support name_to_handle_at()
* fall back to the traditional stat() logic. */
goto fallback;
else if (errno == EOPNOTSUPP)
/* This kernel or file system does not support
* name_to_handle_at(), hence let's see if the
* upper fs supports it (in which case it is a
* mount point), otherwise fallback to the
* traditional stat() logic */
nosupp = true;
else if (errno == ENOENT)
return 0;
else
return -errno;
}
h.handle.handle_bytes = MAX_HANDLE_SZ;
r = name_to_handle_at(fd, "..", &h.handle, &mount_id_parent, 0);
if (r < 0) {
if (errno == EOPNOTSUPP) {
if (nosupp)
/* Neither parent nor child do name_to_handle_at()?
We have no choice but to fall back. */
goto fallback;
else
/* 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. */
return 1;
} else
return -errno;
} else
return mount_id != mount_id_parent;
fallback:
r = fstatat(fd, "", &a, AT_EMPTY_PATH);
if (r < 0) {
if (errno == ENOENT)
return 0;
return -errno;
}
r = fstatat(fd, "..", &b, 0);
if (r < 0)
return -errno;
return a.st_dev != b.st_dev;
}
int path_is_mount_point(const char *t, bool allow_symlink) {
_cleanup_close_ int fd = -1;
assert(t);
if (path_equal(t, "/"))
return 1;
fd = openat(AT_FDCWD, t, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|(allow_symlink ? 0 : O_PATH));
if (fd < 0) {
if (errno == ENOENT)
return 0;
return -errno;
}
return fd_is_mount_point(fd);
}
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;
}