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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "alloc-util.h"
#include "env-file.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "macro.h"
#include "os-util.h"
#include "string-util.h"
#include "strv.h"
int path_is_os_tree(const char *path) {
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 {/etc|/usr/lib}/os-release as flag file if something is an OS */
r = open_os_release(path, NULL, NULL);
if (r == -ENOENT) /* We got nothing */
return 0;
if (r < 0)
return r;
return 1;
}
int open_os_release(const char *root, char **ret_path, int *ret_fd) {
_cleanup_free_ char *q = NULL;
const char *p;
int r, fd;
FOREACH_STRING(p, "/etc/os-release", "/usr/lib/os-release") {
r = chase_symlinks(p, 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_os_release(const char *root, 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_os_release(root, ret_path, NULL);
r = open_os_release(root, ret_path ? &p : NULL, &fd);
if (r < 0)
return r;
f = take_fdopen(&fd, "r");
if (!f)
return -errno;
*ret_file = f;
if (ret_path)
*ret_path = TAKE_PTR(p);
return 0;
}
int parse_os_release(const char *root, ...) {
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ char *p = NULL;
va_list ap;
int r;
r = fopen_os_release(root, &p, &f);
if (r < 0)
return r;
va_start(ap, root);
r = parse_env_filev(f, p, 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;
char **p, **q;
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;
}
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