diff --git a/src/login/pam_systemd.c b/src/login/pam_systemd.c
index 1e38186e77..5de31a9a27 100644
--- a/src/login/pam_systemd.c
+++ b/src/login/pam_systemd.c
@@ -50,28 +50,30 @@ static int parse_argv(
         assert(argc == 0 || argv);
 
         for (i = 0; i < (unsigned) argc; i++) {
-                if (startswith(argv[i], "class=")) {
+                const char *p;
+
+                if ((p = startswith(argv[i], "class="))) {
                         if (class)
-                                *class = argv[i] + 6;
+                                *class = p;
 
-                } else if (startswith(argv[i], "type=")) {
+                } else if ((p = startswith(argv[i], "type="))) {
                         if (type)
-                                *type = argv[i] + 5;
+                                *type = p;
 
-                } else if (startswith(argv[i], "desktop=")) {
+                } else if ((p = startswith(argv[i], "desktop="))) {
                         if (desktop)
-                                *desktop = argv[i] + 8;
+                                *desktop = p;
 
                 } else if (streq(argv[i], "debug")) {
                         if (debug)
                                 *debug = true;
 
-                } else if (startswith(argv[i], "debug=")) {
+                } else if ((p = startswith(argv[i], "debug="))) {
                         int k;
 
-                        k = parse_boolean(argv[i] + 6);
+                        k = parse_boolean(p);
                         if (k < 0)
-                                pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring.");
+                                pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", p);
                         else if (debug)
                                 *debug = k;
 
@@ -97,7 +99,7 @@ static int get_user_data(
 
         r = pam_get_user(handle, &username, NULL);
         if (r != PAM_SUCCESS) {
-                pam_syslog(handle, LOG_ERR, "Failed to get user name.");
+                pam_syslog(handle, LOG_ERR, "Failed to get user name: %s", pam_strerror(handle, r));
                 return r;
         }
 
@@ -383,7 +385,7 @@ static int update_environment(pam_handle_t *handle, const char *key, const char
 
         r = pam_misc_setenv(handle, key, value, 0);
         if (r != PAM_SUCCESS)
-                pam_syslog(handle, LOG_ERR, "Failed to set environment variable %s.", key);
+                pam_syslog(handle, LOG_ERR, "Failed to set environment variable %s: %s", key, pam_strerror(handle, r));
 
         return r;
 }
@@ -391,6 +393,7 @@ static int update_environment(pam_handle_t *handle, const char *key, const char
 static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
         struct stat st;
 
+        assert(handle);
         assert(path);
 
         /* Just some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually set
@@ -459,10 +462,8 @@ _public_ PAM_EXTERN int pam_sm_open_session(
                 pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing");
 
         r = get_user_data(handle, &username, &pw);
-        if (r != PAM_SUCCESS) {
-                pam_syslog(handle, LOG_ERR, "Failed to get user data.");
+        if (r != PAM_SUCCESS)
                 return r;
-        }
 
         /* Make sure we don't enter a loop by talking to
          * systemd-logind when it is actually waiting for the
@@ -470,7 +471,7 @@ _public_ PAM_EXTERN int pam_sm_open_session(
          * "systemd-user" we simply set XDG_RUNTIME_DIR and
          * leave. */
 
-        pam_get_item(handle, PAM_SERVICE, (const void**) &service);
+        (void) pam_get_item(handle, PAM_SERVICE, (const void**) &service);
         if (streq_ptr(service, "systemd-user")) {
                 char rt[STRLEN("/run/user/") + DECIMAL_STR_MAX(uid_t)];
 
@@ -478,7 +479,7 @@ _public_ PAM_EXTERN int pam_sm_open_session(
                 if (validate_runtime_directory(handle, rt, pw->pw_uid)) {
                         r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
                         if (r != PAM_SUCCESS) {
-                                pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+                                pam_syslog(handle, LOG_ERR, "Failed to set runtime dir: %s", pam_strerror(handle, r));
                                 return r;
                         }
                 }
@@ -492,10 +493,10 @@ _public_ PAM_EXTERN int pam_sm_open_session(
 
         /* Otherwise, we ask logind to create a session for us */
 
-        pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
-        pam_get_item(handle, PAM_TTY, (const void**) &tty);
-        pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
-        pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
+        (void) pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
+        (void) pam_get_item(handle, PAM_TTY, (const void**) &tty);
+        (void) pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
+        (void) pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
 
         seat = getenv_harder(handle, "XDG_SEAT", NULL);
         cvtnr = getenv_harder(handle, "XDG_VTNR", NULL);
@@ -660,7 +661,7 @@ _public_ PAM_EXTERN int pam_sm_open_session(
                         return PAM_SUCCESS;
                 } else {
                         pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r));
-                        return PAM_SYSTEM_ERR;
+                        return PAM_SESSION_ERR;
                 }
         }
 
@@ -737,7 +738,7 @@ _public_ PAM_EXTERN int pam_sm_open_session(
 
         r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
         if (r != PAM_SUCCESS) {
-                pam_syslog(handle, LOG_ERR, "Failed to install existing flag.");
+                pam_syslog(handle, LOG_ERR, "Failed to install existing flag: %s", pam_strerror(handle, r));
                 return r;
         }
 
@@ -750,7 +751,7 @@ _public_ PAM_EXTERN int pam_sm_open_session(
 
                 r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(session_fd), NULL);
                 if (r != PAM_SUCCESS) {
-                        pam_syslog(handle, LOG_ERR, "Failed to install session fd.");
+                        pam_syslog(handle, LOG_ERR, "Failed to install session fd: %s", pam_strerror(handle, r));
                         safe_close(session_fd);
                         return r;
                 }