core: normalize error handling a bit, in setup_pam()

Assign errno-style errors to a variable called "r" when they happen, the same way we do this in most other calls. It's
bad enough that the error handling part of the function deals with two different error variables (pam_code and r) now,
but before this fix it was even three!

diff --git a/src/core/execute.c b/src/core/execute.c
index d70ba2b..b9de261 100644 (file)
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -814,8 +814,7 @@ static int setup_pam(
         _cleanup_(barrier_destroy) Barrier barrier = BARRIER_NULL;
         pam_handle_t *handle = NULL;
         sigset_t old_ss;
-        int pam_code = PAM_SUCCESS;
-        int err = 0;
+        int pam_code = PAM_SUCCESS, r;
         char **e = NULL;
         bool close_session = false;
         pid_t pam_pid = 0, parent_pid;
@@ -832,8 +831,8 @@ static int setup_pam(
          * daemon. We do things this way to ensure that the main PID
          * of the daemon is the one we initially fork()ed. */
 
-        err = barrier_create(&barrier);
-        if (err < 0)
+        r = barrier_create(&barrier);
+        if (r < 0)
                 goto fail;
 
         if (log_get_max_level() < LOG_DEBUG)
@@ -875,12 +874,13 @@ static int setup_pam(
         parent_pid = getpid();
 
         pam_pid = fork();
-        if (pam_pid < 0)
+        if (pam_pid < 0) {
+                r = -errno;
                 goto fail;
+        }
 
         if (pam_pid == 0) {
-                int sig;
-                int r = EXIT_PAM;
+                int sig, ret = EXIT_PAM;
 
                 /* The child's job is to reset the PAM session on
                  * termination */
@@ -945,11 +945,11 @@ static int setup_pam(
                                 goto child_finish;
                 }
 
-                r = 0;
+                ret = 0;
 
         child_finish:
                 pam_end(handle, pam_code | flags);
-                _exit(r);
+                _exit(ret);
         }
 
         barrier_set_role(&barrier, BARRIER_PARENT);
@@ -978,10 +978,9 @@ static int setup_pam(
 fail:
         if (pam_code != PAM_SUCCESS) {
                 log_error("PAM failed: %s", pam_strerror(handle, pam_code));
-                err = -EPERM;  /* PAM errors do not map to errno */
-        } else {
-                err = log_error_errno(err < 0 ? err : errno, "PAM failed: %m");
-        }
+                r = -EPERM;  /* PAM errors do not map to errno */
+        } else
+                log_error_errno(r, "PAM failed: %m");
 
         if (handle) {
                 if (close_session)
@@ -993,7 +992,7 @@ fail:
         strv_free(e);
         closelog();
 
-        return err;
+        return r;
 }
 #endif