1 files changed, 164 insertions, 0 deletions
diff --git a/src/shared/offline-passwd.c b/src/shared/offline-passwd.c
new file mode 100644
index 0000000..b607aac
--- /dev/null
+++ b/src/shared/offline-passwd.c
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "fd-util.h"
+#include "fs-util.h"
+#include "offline-passwd.h"
+#include "path-util.h"
+#include "user-util.h"
+
+DEFINE_PRIVATE_HASH_OPS_WITH_KEY_DESTRUCTOR(uid_gid_hash_ops, char, string_hash_func, string_compare_func, free);
+
+static int open_passwd_file(const char *root, const char *fname, FILE **ret_file) {
+        _cleanup_free_ char *p = NULL;
+        _cleanup_close_ int fd = -1;
+
+        fd = chase_symlinks_and_open(fname, root, CHASE_PREFIX_ROOT, O_RDONLY|O_CLOEXEC, &p);
+        if (fd < 0)
+                return fd;
+
+        FILE *f = fdopen(fd, "r");
+        if (!f)
+                return -errno;
+
+        TAKE_FD(fd);
+
+        log_debug("Reading %s entries from %s...", basename(fname), p);
+
+        *ret_file = f;
+        return 0;
+}
+
+static int populate_uid_cache(const char *root, Hashmap **ret) {
+        _cleanup_(hashmap_freep) Hashmap *cache = NULL;
+        int r;
+
+        cache = hashmap_new(&uid_gid_hash_ops);
+        if (!cache)
+                return -ENOMEM;
+
+        /* The directory list is hardcoded here: /etc is the standard, and rpm-ostree uses /usr/lib. This
+         * could be made configurable, but I don't see the point right now. */
+
+        const char *fname;
+        FOREACH_STRING(fname, "/etc/passwd", "/usr/lib/passwd") {
+                _cleanup_fclose_ FILE *f = NULL;
+
+                r = open_passwd_file(root, fname, &f);
+                if (r == -ENOENT)
+                        continue;
+                if (r < 0)
+                        return r;
+
+                struct passwd *pw;
+                while ((r = fgetpwent_sane(f, &pw)) > 0) {
+                        _cleanup_free_ char *n = NULL;
+
+                        n = strdup(pw->pw_name);
+                        if (!n)
+                                return -ENOMEM;
+
+                        r = hashmap_put(cache, n, UID_TO_PTR(pw->pw_uid));
+                        if (IN_SET(r, 0 -EEXIST))
+                                continue;
+                        if (r < 0)
+                                return r;
+                        TAKE_PTR(n);
+                }
+        }
+
+        *ret = TAKE_PTR(cache);
+        return 0;
+}
+
+static int populate_gid_cache(const char *root, Hashmap **ret) {
+        _cleanup_(hashmap_freep) Hashmap *cache = NULL;
+        int r;
+
+        cache = hashmap_new(&uid_gid_hash_ops);
+        if (!cache)
+                return -ENOMEM;
+
+        const char *fname;
+        FOREACH_STRING(fname, "/etc/group", "/usr/lib/group") {
+                _cleanup_fclose_ FILE *f = NULL;
+
+                r = open_passwd_file(root, fname, &f);
+                if (r == -ENOENT)
+                        continue;
+                if (r < 0)
+                        return r;
+
+                struct group *gr;
+                while ((r = fgetgrent_sane(f, &gr)) > 0) {
+                        _cleanup_free_ char *n = NULL;
+
+                        n = strdup(gr->gr_name);
+                        if (!n)
+                                return -ENOMEM;
+
+                        r = hashmap_put(cache, n, GID_TO_PTR(gr->gr_gid));
+                        if (IN_SET(r, 0, -EEXIST))
+                                continue;
+                        if (r < 0)
+                                return r;
+                        TAKE_PTR(n);
+                }
+        }
+
+        *ret = TAKE_PTR(cache);
+        return 0;
+}
+
+int name_to_uid_offline(
+                const char *root,
+                const char *user,
+                uid_t *ret_uid,
+                Hashmap **cache) {
+
+        void *found;
+        int r;
+
+        assert(user);
+        assert(ret_uid);
+        assert(cache);
+
+        if (!*cache) {
+                r = populate_uid_cache(root, cache);
+                if (r < 0)
+                        return r;
+        }
+
+        found = hashmap_get(*cache, user);
+        if (!found)
+                return -ESRCH;
+
+        *ret_uid = PTR_TO_UID(found);
+        return 0;
+}
+
+int name_to_gid_offline(
+                const char *root,
+                const char *group,
+                gid_t *ret_gid,
+                Hashmap **cache) {
+
+        void *found;
+        int r;
+
+        assert(group);
+        assert(ret_gid);
+        assert(cache);
+
+        if (!*cache) {
+                r = populate_gid_cache(root, cache);
+                if (r < 0)
+                        return r;
+        }
+
+        found = hashmap_get(*cache, group);
+        if (!found)
+                return -ESRCH;
+
+        *ret_gid = PTR_TO_GID(found);
+        return 0;
+}