/*
* Copyright (C) 2011 Davidlohr Bueso <dave@gnu.org>
*
* procutils.c: General purpose procfs parsing utilities
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library Public License for more details.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <dirent.h>
#include <ctype.h>
#include "procutils.h"
#include "c.h"
/*
* @pid: process ID for which we want to obtain the threads group
*
* Returns: newly allocated tasks structure
*/
struct proc_tasks *proc_open_tasks(pid_t pid)
{
struct proc_tasks *tasks;
char path[PATH_MAX];
sprintf(path, "/proc/%d/task/", pid);
tasks = malloc(sizeof(struct proc_tasks));
if (tasks) {
tasks->dir = opendir(path);
if (tasks->dir)
return tasks;
}
free(tasks);
return NULL;
}
/*
* @tasks: allocated tasks structure
*
* Returns: nothing
*/
void proc_close_tasks(struct proc_tasks *tasks)
{
if (tasks && tasks->dir)
closedir(tasks->dir);
free(tasks);
}
/*
* @tasks: allocated task structure
* @tid: [output] one of the thread IDs belonging to the thread group
* If when an error occurs, it is set to 0.
*
* Returns: 0 on success, 1 on end, -1 on failure or no more threads
*/
int proc_next_tid(struct proc_tasks *tasks, pid_t *tid)
{
struct dirent *d;
char *end;
if (!tasks || !tid)
return -1;
*tid = 0;
errno = 0;
do {
d = readdir(tasks->dir);
if (!d)
return errno ? -1 : 1; /* error or end-of-dir */
if (!isdigit((unsigned char) *d->d_name))
continue;
*tid = (pid_t) strtol(d->d_name, &end, 10);
if (errno || d->d_name == end || (end && *end))
return -1;
} while (!*tid);
return 0;
}
#ifdef TEST_PROGRAM
int main(int argc, char *argv[])
{
pid_t tid, pid;
struct proc_tasks *ts;
if (argc != 2) {
fprintf(stderr, "usage: %s <pid>\n", argv[0]);
return EXIT_FAILURE;
}
pid = strtol(argv[1], (char **) NULL, 10);
printf("PID=%d, TIDs:", pid);
ts = proc_open_tasks(pid);
if (!ts)
err(EXIT_FAILURE, "open list of tasks failed");
while (proc_next_tid(ts, &tid) == 0)
printf(" %d", tid);
printf("\n");
proc_close_tasks(ts);
return EXIT_SUCCESS;
}
#endif /* TEST_PROGRAM */
