sd-login: add calls that retrieve credentials of peers connected to AF_UNIX peers

This is supposed to be an extension of SO_PEERCRED and SO_PEERSEC,
except for cgroup information.

2 files changed, 93 insertions, 5 deletions

diff --git a/src/login/sd-login.c b/src/login/sd-login.c
index 4ad250eb37..d24b2ed1fd 100644
--- a/src/login/sd-login.c
+++ b/src/login/sd-login.c
@@ -81,8 +81,93 @@ _public_ int sd_pid_get_owner_uid(pid_t pid, uid_t *uid) {
         return cg_pid_get_owner_uid(pid, uid);
 }
 
+_public_ int sd_peer_get_session(int fd, char **session) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EINVAL);
+        assert_return(session, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_session(ucred.pid, session);
+}
+
+_public_ int sd_peer_get_owner_uid(int fd, uid_t *uid) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EINVAL);
+        assert_return(uid, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_owner_uid(ucred.pid, uid);
+}
+
+_public_ int sd_peer_get_unit(int fd, char **unit) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EINVAL);
+        assert_return(unit, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_unit(ucred.pid, unit);
+}
+
+_public_ int sd_peer_get_user_unit(int fd, char **unit) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EINVAL);
+        assert_return(unit, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_user_unit(ucred.pid, unit);
+}
+
+_public_ int sd_peer_get_machine_name(int fd, char **machine) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EINVAL);
+        assert_return(machine, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_machine_name(ucred.pid, machine);
+}
+
+_public_ int sd_peer_get_slice(int fd, char **slice) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EINVAL);
+        assert_return(slice, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_slice(ucred.pid, slice);
+}
+
 _public_ int sd_uid_get_state(uid_t uid, char**state) {
-        char *p, *s = NULL;
+        _cleanup_free_ char *p = NULL;
+        char *s = NULL;
         int r;
 
         assert_return(state, -EINVAL);
@@ -91,16 +176,12 @@ _public_ int sd_uid_get_state(uid_t uid, char**state) {
                 return -ENOMEM;
 
         r = parse_env_file(p, NEWLINE, "STATE", &s, NULL);
-        free(p);
-
         if (r == -ENOENT) {
                 free(s);
                 s = strdup("offline");
                 if (!s)
                         return -ENOMEM;
 
-                *state = s;
-                return 0;
         } else if (r < 0) {
                 free(s);
                 return r;
diff --git a/src/login/test-login.c b/src/login/test-login.c
index d78cea46af..2ab083bb71 100644
--- a/src/login/test-login.c
+++ b/src/login/test-login.c
@@ -28,6 +28,8 @@
 #include "strv.h"
 
 static void test_login(void) {
+        _cleanup_close_pipe_ int pair[2] = { -1, -1 };
+        _cleanup_free_ char *pp = NULL, *qq = NULL;
         int r, k;
         uid_t u, u2;
         char *seat, *type, *class, *display, *remote_user, *remote_host;
@@ -47,6 +49,11 @@ static void test_login(void) {
         assert_se(sd_pid_get_owner_uid(0, &u2) == 0);
         printf("user = %lu\n", (unsigned long) u2);
 
+        assert_se(socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == 0);
+        sd_peer_get_session(pair[0], &pp);
+        sd_peer_get_session(pair[1], &qq);
+        assert_se(streq_ptr(pp, qq));
+
         r = sd_uid_get_sessions(u2, false, &sessions);
         assert_se(r >= 0);
         assert_se(r == (int) strv_length(sessions));