improve setting command path in MacOS

src/process_iterator_apple.c

@@ -93,22 +93,48 @@ int init_process_iterator(struct process_iterator *it, struct process_filter *fi
     return 0;
 }
 
-static void pti2proc(struct proc_taskallinfo *ti, struct process *process)
+static int get_process_path(int pid, char *pathbuf, size_t buf_size)
 {
-    process->pid = ti->pbsd.pbi_pid;
-    process->ppid = ti->pbsd.pbi_ppid;
-    process->cputime = ti->ptinfo.pti_total_user / 1e6 + ti->ptinfo.pti_total_system / 1e6;
-    if (ti->pbsd.pbi_name[0] != '\0')
+    int mib[3] = {CTL_KERN, KERN_ARGMAX, pid};
+    size_t len;
+    char **argv;
+
+    if (sysctl(mib, 3, &len, &len, NULL, 0) == -1)
+    {
+        perror("sysctl");
+        return -1;
+    }
+
+    argv = (char **)malloc(len);
+    if (argv == NULL)
     {
-        process->max_cmd_len = MIN(sizeof(process->command), sizeof(ti->pbsd.pbi_name)) - 1;
-        strncpy(process->command, ti->pbsd.pbi_name, process->max_cmd_len);
+        perror("malloc");
+        return -1;
     }
-    else
+
+    mib[1] = KERN_PROCARGS2;
+
+    if (sysctl(mib, 3, argv, &len, NULL, 0) == -1)
     {
-        process->max_cmd_len = MIN(sizeof(process->command), sizeof(ti->pbsd.pbi_comm)) - 1;
-        strncpy(process->command, ti->pbsd.pbi_comm, process->max_cmd_len);
+        perror("sysctl");
+        free(argv);
+        return -1;
     }
-    process->command[process->max_cmd_len] = '\0';
+
+    strcpy(pathbuf, argv[0]);
+
+    free(argv);
+
+    return 0;
+}
+
+static void pti2proc(struct proc_taskallinfo *ti, struct process *process)
+{
+    process->pid = ti->pbsd.pbi_pid;
+    process->ppid = ti->pbsd.pbi_ppid;
+    process->cputime = ti->ptinfo.pti_total_user / 1e6 + ti->ptinfo.pti_total_system / 1e6;
+    get_process_path(ti->pbsd.pbi_pid, process->command, sizeof(process->command));
+    process->max_cmd_len = sizeof(process->command) - 1;
 }
 
 static int get_process_pti(pid_t pid, struct proc_taskallinfo *ti)