systemd: Cleanup return codes in cgroup_create_scope()

cgroup_create_scope() used a single variable, ret, to handle return
codes from systemd/dbus, system calls, and internal libcgroup functions.
Use a separate return variable for each of these three cases to clearly
delineate errors.

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
(cherry picked from commit 41a2451f4e360de90c5d00c32464da73c016f016)

diff --git a/src/systemd.c b/src/systemd.c
index 8cd108a59ac8c92d39f9e8fb7dcf76c6aa120c30..5f96cb6f1137bb80081bfe4b186cb990d9af8479 100644 (file)
--- a/src/systemd.c
+++ b/src/systemd.c
@@ -88,12 +88,12 @@ int cgroup_create_scope(const char * const scope_name, const char * const slice_
                        const struct cgroup_systemd_scope_opts * const opts)
 {
        sd_bus_message *msg = NULL, *reply = NULL;
+       int ret = 0, sdret = 0, cgret = ECGFAIL;
        sd_bus_error error = SD_BUS_ERROR_NULL;
        const char *job_path = NULL;
        struct timespec start, now;
        sd_bus *bus = NULL;
        pid_t child_pid;
-       int ret = 0;
 
        if (!scope_name || !slice_name || !opts)
                return ECGINVAL;
@@ -141,79 +141,79 @@ int cgroup_create_scope(const char * const scope_name, const char * const slice_
        }
        cgroup_dbg("pid %d will be placed in scope %s\n", child_pid, scope_name);
 
-       ret = sd_bus_default_system(&bus);
-       if (ret < 0) {
+       sdret = sd_bus_default_system(&bus);
+       if (sdret < 0) {
                cgroup_err("failed to open the system bus: %d\n", errno);
                goto out;
        }
 
-       ret = sd_bus_match_signal(bus, NULL, sender, path, interface,
-                                 "JobRemoved", job_removed_callback, &job_path);
-       if (ret < 0) {
+       sdret = sd_bus_match_signal(bus, NULL, sender, path, interface,
+                                   "JobRemoved", job_removed_callback, &job_path);
+       if (sdret < 0) {
                cgroup_err("failed to install match callback: %d\n", errno);
                goto out;
        }
 
-       ret = sd_bus_message_new_method_call(bus, &msg, sender, path, interface,
-                                            "StartTransientUnit");
-       if (ret < 0) {
+       sdret = sd_bus_message_new_method_call(bus, &msg, sender, path, interface,
+                                              "StartTransientUnit");
+       if (sdret < 0) {
                cgroup_err("failed to create the systemd msg: %d\n", errno);
                goto out;
        }
 
-       ret = sd_bus_message_append(msg, "ss", scope_name, modes[opts->mode]);
-       if (ret < 0) {
+       sdret = sd_bus_message_append(msg, "ss", scope_name, modes[opts->mode]);
+       if (sdret < 0) {
                cgroup_err("failed to append the scope name: %d\n", errno);
                goto out;
        }
 
-       ret = sd_bus_message_open_container(msg, 'a', "(sv)");
-       if (ret < 0) {
+       sdret = sd_bus_message_open_container(msg, 'a', "(sv)");
+       if (sdret < 0) {
                cgroup_err("failed to open container: %d\n", errno);
                goto out;
        }
 
-       ret = sd_bus_message_append(msg, "(sv)", "Description", "s",
-                                   "scope created by libcgroup");
-       if (ret < 0) {
+       sdret = sd_bus_message_append(msg, "(sv)", "Description", "s",
+                                     "scope created by libcgroup");
+       if (sdret < 0) {
                cgroup_err("failed to append the description: %d\n", errno);
                goto out;
        }
 
-       ret = sd_bus_message_append(msg, "(sv)", "PIDs", "au", 1, child_pid);
-       if (ret < 0) {
+       sdret = sd_bus_message_append(msg, "(sv)", "PIDs", "au", 1, child_pid);
+       if (sdret < 0) {
                cgroup_err("failed to append the PID: %d\n", errno);
                goto out;
        }
 
-       ret = sd_bus_message_append(msg, "(sv)", "Slice", "s", slice_name);
-       if (ret < 0) {
+       sdret = sd_bus_message_append(msg, "(sv)", "Slice", "s", slice_name);
+       if (sdret < 0) {
                cgroup_err("failed to append the slice: %d\n", errno);
                goto out;
        }
 
        if (opts->delegated == 1) {
-               ret = sd_bus_message_append(msg, "(sv)", "Delegate", "b", 1);
-               if (ret < 0) {
+               sdret = sd_bus_message_append(msg, "(sv)", "Delegate", "b", 1);
+               if (sdret < 0) {
                        cgroup_err("failed to append delegate: %d\n", errno);
                        goto out;
                }
        }
 
-       ret = sd_bus_message_close_container(msg);
-       if (ret < 0) {
+       sdret = sd_bus_message_close_container(msg);
+       if (sdret < 0) {
                cgroup_err("failed to close the container: %d\n", errno);
                goto out;
        }
 
-       ret = sd_bus_message_append(msg, "a(sa(sv))", 0);
-       if (ret < 0) {
+       sdret = sd_bus_message_append(msg, "a(sa(sv))", 0);
+       if (sdret < 0) {
                cgroup_err("failed to append aux structure: %d\n", errno);
                goto out;
        }
 
-       ret = sd_bus_call(bus, msg, 0, &error, &reply);
-       if (ret < 0) {
+       sdret = sd_bus_call(bus, msg, 0, &error, &reply);
+       if (sdret < 0) {
                cgroup_err("sd_bus_call() failed: %d\n",
                           sd_bus_message_get_errno(msg));
                cgroup_err("error message: %s\n", error.message);
@@ -221,8 +221,8 @@ int cgroup_create_scope(const char * const scope_name, const char * const slice_
        }
 
        /* Receive the job_path from systemd */
-       ret = sd_bus_message_read(reply, "o", &job_path);
-       if (ret < 0) {
+       sdret = sd_bus_message_read(reply, "o", &job_path);
+       if (sdret < 0) {
                cgroup_err("failed to read reply: %d\n", errno);
                goto out;
        }
@@ -232,25 +232,25 @@ int cgroup_create_scope(const char * const scope_name, const char * const slice_
        ret = clock_gettime(CLOCK_MONOTONIC, &start);
        if (ret < 0) {
                cgroup_err("Failed to get time: %d\n", errno);
-               ret = ECGFAIL;
+               cgret = ECGOTHER;
                goto out;
        }
 
        /* The callback will null out the job_path pointer on completion */
        while(job_path) {
-               ret = sd_bus_process(bus, NULL);
-               if (ret < 0) {
+               sdret = sd_bus_process(bus, NULL);
+               if (sdret < 0) {
                        cgroup_err("failed to process the sd bus: %d\n", errno);
                        goto out;
                }
 
-               if (ret == 0) {
+               if (sdret == 0) {
                        /*
                         * Per the sd_bus_wait() man page, call this function after sd_bus_process
                         * returns zero. The wait time (usec) was somewhat arbitrarily chosen
                         */
-                       ret = sd_bus_wait(bus, 10);
-                       if (ret < 0) {
+                       sdret = sd_bus_wait(bus, 10);
+                       if (sdret < 0) {
                                cgroup_err("failed to wait for sd bus: %d\n", errno);
                                goto out;
                        }
@@ -259,21 +259,20 @@ int cgroup_create_scope(const char * const scope_name, const char * const slice_
                ret = clock_gettime(CLOCK_MONOTONIC, &now);
                if (ret < 0) {
                        cgroup_err("Failed to get time: %d\n", errno);
-                       ret = ECGFAIL;
+                       cgret = ECGOTHER;
                        goto out;
                }
 
                if (elapsed_time(&start, &now) > USEC_PER_SEC) {
                        cgroup_err("The create scope command timed out\n");
-                       ret = ECGFAIL;
                        goto out;
                }
        }
 
-       ret = 0;
+       cgret = 0;
 
 out:
-       if (ret && opts->pid < 0)
+       if (cgret && opts->pid < 0)
                kill(child_pid, SIGTERM);
 
        sd_bus_error_free(&error);
@@ -281,7 +280,7 @@ out:
        sd_bus_message_unref(reply);
        sd_bus_unref(bus);
 
-       return ret;
+       return cgret;
 }
 
 int cgroup_create_scope2(struct cgroup *cgroup, int ignore_ownership,