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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "alloc-util.h"
#include "chase-symlinks.h"
#include "dirent-util.h"
#include "env-file.h"
#include "env-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "macro.h"
#include "os-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "stat-util.h"
#include "string-util.h"
#include "strv.h"
#include "utf8.h"
#include "xattr-util.h"
bool image_name_is_valid(const char *s) {
if (!filename_is_valid(s))
return false;
if (string_has_cc(s, NULL))
return false;
if (!utf8_is_valid(s))
return false;
/* Temporary files for atomically creating new files */
if (startswith(s, ".#"))
return false;
return true;
}
int path_is_extension_tree(const char *path, const char *extension) {
int r;
assert(path);
/* Does the path exist at all? If not, generate an error immediately. This is useful so that a missing root dir
* always results in -ENOENT, and we can properly distinguish the case where the whole root doesn't exist from
* the case where just the os-release file is missing. */
if (laccess(path, F_OK) < 0)
return -errno;
/* We use /usr/lib/extension-release.d/extension-release[.NAME] as flag for something being a system extension,
* and {/etc|/usr/lib}/os-release as a flag for something being an OS (when not an extension). */
r = open_extension_release(path, extension, NULL, NULL);
if (r == -ENOENT) /* We got nothing */
return 0;
if (r < 0)
return r;
return 1;
}
int open_extension_release(const char *root, const char *extension, char **ret_path, int *ret_fd) {
_cleanup_free_ char *q = NULL;
int r, fd;
if (extension) {
const char *extension_full_path;
if (!image_name_is_valid(extension))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"The extension name %s is invalid.", extension);
extension_full_path = strjoina("/usr/lib/extension-release.d/extension-release.", extension);
r = chase_symlinks(extension_full_path, root, CHASE_PREFIX_ROOT,
ret_path ? &q : NULL,
ret_fd ? &fd : NULL);
log_full_errno_zerook(LOG_DEBUG, MIN(r, 0), "Checking for %s: %m", extension_full_path);
/* Cannot find the expected extension-release file? The image filename might have been
* mangled on deployment, so fallback to checking for any file in the extension-release.d
* directory, and return the first one with a user.extension-release xattr instead.
* The user.extension-release.strict xattr is checked to ensure the author of the image
* considers it OK if names do not match. */
if (r == -ENOENT) {
_cleanup_free_ char *extension_release_dir_path = NULL;
_cleanup_closedir_ DIR *extension_release_dir = NULL;
r = chase_symlinks_and_opendir("/usr/lib/extension-release.d/", root, CHASE_PREFIX_ROOT,
&extension_release_dir_path, &extension_release_dir);
if (r < 0)
return log_debug_errno(r, "Cannot open %s/usr/lib/extension-release.d/, ignoring: %m", root);
r = -ENOENT;
FOREACH_DIRENT(de, extension_release_dir, return -errno) {
int k;
if (!IN_SET(de->d_type, DT_REG, DT_UNKNOWN))
continue;
const char *image_name = startswith(de->d_name, "extension-release.");
if (!image_name)
continue;
if (!image_name_is_valid(image_name)) {
log_debug("%s/%s is not a valid extension-release file name, ignoring.",
extension_release_dir_path, de->d_name);
continue;
}
/* We already chased the directory, and checked that
* this is a real file, so we shouldn't fail to open it. */
_cleanup_close_ int extension_release_fd = openat(dirfd(extension_release_dir),
de->d_name,
O_PATH|O_CLOEXEC|O_NOFOLLOW);
if (extension_release_fd < 0)
return log_debug_errno(errno,
"Failed to open extension-release file %s/%s: %m",
extension_release_dir_path,
de->d_name);
/* Really ensure it is a regular file after we open it. */
if (fd_verify_regular(extension_release_fd) < 0) {
log_debug("%s/%s is not a regular file, ignoring.", extension_release_dir_path, de->d_name);
continue;
}
/* No xattr or cannot parse it? Then skip this. */
_cleanup_free_ char *extension_release_xattr = NULL;
k = fgetxattr_malloc(extension_release_fd, "user.extension-release.strict", &extension_release_xattr);
if (k < 0 && !ERRNO_IS_NOT_SUPPORTED(k) && k != -ENODATA)
log_debug_errno(k,
"%s/%s: Failed to read 'user.extension-release.strict' extended attribute from file: %m",
extension_release_dir_path, de->d_name);
if (k < 0) {
log_debug("%s/%s does not have user.extension-release.strict xattr, ignoring.", extension_release_dir_path, de->d_name);
continue;
}
/* Explicitly set to request strict matching? Skip it. */
k = parse_boolean(extension_release_xattr);
if (k < 0)
log_debug_errno(k,
"%s/%s: Failed to parse 'user.extension-release.strict' extended attribute from file: %m",
extension_release_dir_path, de->d_name);
else if (k > 0)
log_debug("%s/%s: 'user.extension-release.strict' attribute is true, ignoring file.",
extension_release_dir_path, de->d_name);
if (k != 0)
continue;
log_debug("%s/%s: 'user.extension-release.strict' attribute is false…",
extension_release_dir_path, de->d_name);
/* We already found what we were looking for, but there's another candidate?
* We treat this as an error, as we want to enforce that there are no ambiguities
* in case we are in the fallback path.*/
if (r == 0) {
r = -ENOTUNIQ;
break;
}
r = 0; /* Found it! */
if (ret_fd)
fd = TAKE_FD(extension_release_fd);
if (ret_path) {
q = path_join(extension_release_dir_path, de->d_name);
if (!q)
return -ENOMEM;
}
}
}
} else {
const char *var = secure_getenv("SYSTEMD_OS_RELEASE");
if (var)
r = chase_symlinks(var, root, 0,
ret_path ? &q : NULL,
ret_fd ? &fd : NULL);
else
FOREACH_STRING(path, "/etc/os-release", "/usr/lib/os-release") {
r = chase_symlinks(path, root, CHASE_PREFIX_ROOT,
ret_path ? &q : NULL,
ret_fd ? &fd : NULL);
if (r != -ENOENT)
break;
}
}
if (r < 0)
return r;
if (ret_fd) {
int real_fd;
/* Convert the O_PATH fd into a proper, readable one */
real_fd = fd_reopen(fd, O_RDONLY|O_CLOEXEC|O_NOCTTY);
safe_close(fd);
if (real_fd < 0)
return real_fd;
*ret_fd = real_fd;
}
if (ret_path)
*ret_path = TAKE_PTR(q);
return 0;
}
int fopen_extension_release(const char *root, const char *extension, char **ret_path, FILE **ret_file) {
_cleanup_free_ char *p = NULL;
_cleanup_close_ int fd = -1;
FILE *f;
int r;
if (!ret_file)
return open_extension_release(root, extension, ret_path, NULL);
r = open_extension_release(root, extension, ret_path ? &p : NULL, &fd);
if (r < 0)
return r;
f = take_fdopen(&fd, "r");
if (!f)
return -errno;
if (ret_path)
*ret_path = TAKE_PTR(p);
*ret_file = f;
return 0;
}
static int parse_release_internal(const char *root, const char *extension, va_list ap) {
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ char *p = NULL;
int r;
r = fopen_extension_release(root, extension, &p, &f);
if (r < 0)
return r;
return parse_env_filev(f, p, ap);
}
int _parse_extension_release(const char *root, const char *extension, ...) {
va_list ap;
int r;
va_start(ap, extension);
r = parse_release_internal(root, extension, ap);
va_end(ap);
return r;
}
int _parse_os_release(const char *root, ...) {
va_list ap;
int r;
va_start(ap, root);
r = parse_release_internal(root, NULL, ap);
va_end(ap);
return r;
}
int load_os_release_pairs(const char *root, char ***ret) {
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ char *p = NULL;
int r;
r = fopen_os_release(root, &p, &f);
if (r < 0)
return r;
return load_env_file_pairs(f, p, ret);
}
int load_os_release_pairs_with_prefix(const char *root, const char *prefix, char ***ret) {
_cleanup_strv_free_ char **os_release_pairs = NULL, **os_release_pairs_prefixed = NULL;
int r;
r = load_os_release_pairs(root, &os_release_pairs);
if (r < 0)
return r;
STRV_FOREACH_PAIR(p, q, os_release_pairs) {
char *line;
/* We strictly return only the four main ID fields and ignore the rest */
if (!STR_IN_SET(*p, "ID", "VERSION_ID", "BUILD_ID", "VARIANT_ID"))
continue;
ascii_strlower(*p);
line = strjoin(prefix, *p, "=", *q);
if (!line)
return -ENOMEM;
r = strv_consume(&os_release_pairs_prefixed, line);
if (r < 0)
return r;
}
*ret = TAKE_PTR(os_release_pairs_prefixed);
return 0;
}
int load_extension_release_pairs(const char *root, const char *extension, char ***ret) {
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ char *p = NULL;
int r;
r = fopen_extension_release(root, extension, &p, &f);
if (r < 0)
return r;
return load_env_file_pairs(f, p, ret);
}
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