initctl: refactor pid_cgroup(), return allocated buffer

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/cgutil.c

@@ -121,23 +121,43 @@ char *pid_comm(int pid, char *buf, size_t len)
 	return ptr;
 }
 
-char *pid_cgroup(int pid, char *buf, size_t len)
+char *pid_cgroup(int pid)
 {
-	char *ptr = NULL;
+	char *buf, *ptr = NULL;
+	size_t len;
 	FILE *fp;
 
 	fp = fopenf("r", "/proc/%d/cgroup", pid);
 	if (!fp)
 		return NULL;
 
+	len = flen(fp);
+	if (len == 0) {
+		fclose(fp);
+		return NULL;
+	}
+	len++;
+
+	buf = calloc(1, len);
+	if (!buf) {
+		fclose(fp);
+		return NULL;
+	}
+
 	if (fgets(buf, len, fp))
 		ptr = chomp(buf);
 	fclose(fp);
 
-	if (ptr)
-		ptr = strchr(buf, '/');
+	if (ptr) {
+		ptr = strchr(ptr, '/');
+		if (ptr) {
+			memmove(buf, ptr, strlen(ptr) + 1);
+			return buf;
+		}
+	}
 
-	return ptr;
+	free(buf);
+	return NULL;
 }
 
 static char *cgroup_val(char *path, char *file, char *buf, size_t len)

src/cgutil.h

@@ -56,7 +56,7 @@ int cgroup_avail(void);
 
 char *pid_cmdline (int pid);
 char *pid_comm    (int pid, char *buf, size_t len);
-char *pid_cgroup  (int pid, char *buf, size_t len);
+char *pid_cgroup  (int pid);
 
 uint64_t cgroup_memory(char *group);
 

src/initctl.c

@@ -1135,14 +1135,14 @@ static int show_status(char *arg)
 		printf("   Restarts : %d (%d/%d)\n", svc->restart_tot, svc->restart_cnt, svc->restart_max);
 		printf("  Runlevels : %s\n", runlevel_string(runlevel, svc->runlevels));
 		if (cgrp && svc->pid > 1) {
-			char grbuf[128];
+			const struct cg *cg;
 			char path[256];
-			struct cg *cg;
 			char *group;
 
-			group = pid_cgroup(svc->pid, grbuf, sizeof(grbuf));
+			group = pid_cgroup(svc->pid);
 			if (!group)
 				goto no_cgroup; /* ... or PID doesn't exist (anymore) */
+
 			snprintf(path, sizeof(path), "%s/%s", FINIT_CGPATH, group);
 			cg = cg_conf(path);
 
@@ -1151,6 +1151,8 @@ static int show_status(char *arg)
 			       group, cg->cg_cpu.set, cg->cg_cpu.weight, cg->cg_cpu.max,
 			       cg->cg_mem.min, cg->cg_mem.max);
 			show_cgroup_tree(group, "              ");
+
+			free(group);
 		}
 	no_cgroup:
 		printf("\n");