nspawn: spawn shell under specified --user

[elogind.git] / src / util.c

diff --git a/src/util.c b/src/util.c
index a0c04e3204f81b259e4f84d0884338c6c30645be..f75df7b5116c68662decce5ac1f27a6a0897f0c6 100644 (file)
--- a/src/util.c
+++ b/src/util.c
@@ -64,6 +64,9 @@
 #include "exit-status.h"
 #include "hashmap.h"
 
+int saved_argc = 0;
+char **saved_argv = NULL;
+
 size_t page_size(void) {
         static __thread size_t pgsz = 0;
         long r;
@@ -3026,6 +3029,20 @@ void rename_process(const char name[8]) {
 
         if (program_invocation_name)
                 strncpy(program_invocation_name, name, strlen(program_invocation_name));
+
+        if (saved_argc > 0) {
+                int i;
+
+                if (saved_argv[0])
+                        strncpy(saved_argv[0], name, strlen(saved_argv[0]));
+
+                for (i = 1; i < saved_argc; i++) {
+                        if (!saved_argv[i])
+                                break;
+
+                        memset(saved_argv[i], 0, strlen(saved_argv[i]));
+                }
+        }
 }
 
 void sigset_add_many(sigset_t *ss, ...) {
@@ -5171,6 +5188,52 @@ int socket_from_display(const char *display, char **path) {
         return 0;
 }
 
+int get_user_creds(const char **username, uid_t *uid, gid_t *gid, const char **home) {
+        struct passwd *p;
+        unsigned long lu;
+
+        assert(username);
+        assert(*username);
+        assert(uid);
+        assert(gid);
+        assert(home);
+
+        /* We enforce some special rules for uid=0: in order to avoid
+         * NSS lookups for root we hardcode its data. */
+
+        if (streq(*username, "root") || streq(*username, "0")) {
+                *username = "root";
+                *uid = 0;
+                *gid = 0;
+                *home = "/root";
+                return 0;
+        }
+
+        if (safe_atolu(*username, &lu) >= 0) {
+                errno = 0;
+                p = getpwuid((uid_t) lu);
+
+                /* If there are multiple users with the same id, make
+                 * sure to leave $USER to the configured value instead
+                 * of the first occurrence in the database. However if
+                 * the uid was configured by a numeric uid, then let's
+                 * pick the real username from /etc/passwd. */
+                if (p)
+                        *username = p->pw_name;
+        } else {
+                errno = 0;
+                p = getpwnam(*username);
+        }
+
+        if (!p)
+                return errno != 0 ? -errno : -ESRCH;
+
+        *uid = p->pw_uid;
+        *gid = p->pw_gid;
+        *home = p->pw_dir;
+        return 0;
+}
+
 static const char *const ioprio_class_table[] = {
         [IOPRIO_CLASS_NONE] = "none",
         [IOPRIO_CLASS_RT] = "realtime",