/*
   Copyright (c) 2011-2012 Red Hat, Inc. <http://www.redhat.com>
   This file is part of GlusterFS.

   This file is licensed to you under your choice of the GNU Lesser
   General Public License, version 3 or any later version (LGPLv3 or
   later), or the GNU General Public License, version 2 (GPLv2), in all
   cases as published by the Free Software Foundation.
*/

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <sys/param.h> /* for PATH_MAX */

#include <glusterfs/common-utils.h>
#include <glusterfs/syscall.h>
#include "procdiggy.h"

pid_t
pidinfo(pid_t pid, char **name)
{
    char buf[NAME_MAX * 2] = {
        0,
    };
    FILE *f = NULL;
    char path[PATH_MAX] = {
        0,
    };
    char *p = NULL;
    int ret = 0;

    snprintf(path, sizeof path, PROC "/%d/status", pid);

    f = fopen(path, "r");
    if (!f)
        return -1;

    if (name)
        *name = NULL;
    for (;;) {
        size_t len;
        memset(buf, 0, sizeof(buf));
        if (fgets(buf, sizeof(buf), f) == NULL || (len = strlen(buf)) == 0 ||
            buf[len - 1] != '\n') {
            pid = -1;
            goto out;
        }
        buf[len - 1] = '\0';

        if (name && !*name) {
            p = strtail(buf, "Name:");
            if (p) {
                while (isspace(*++p))
                    ;
                *name = gf_strdup(p);
                if (!*name) {
                    pid = -2;
                    goto out;
                }
                continue;
            }
        }

        p = strtail(buf, "PPid:");
        if (p)
            break;
    }

    while (isspace(*++p))
        ;
    ret = gf_string2int(p, &pid);
    if (ret == -1)
        pid = -1;

out:
    fclose(f);
    if (pid == -1 && name && *name)
        GF_FREE(*name);
    if (pid == -2)
        fprintf(stderr, "out of memory\n");
    return pid;
}

int
prociter(int (*proch)(pid_t pid, pid_t ppid, char *tmpname, void *data),
         void *data)
{
    char *name = NULL;
    DIR *d = NULL;
    struct dirent *de = NULL;
    struct dirent scratch[2] = {
        {
            0,
        },
    };
    pid_t pid = -1;
    pid_t ppid = -1;
    int ret = 0;

    d = sys_opendir(PROC);
    if (!d)
        return -1;

    for (;;) {
        errno = 0;
        de = sys_readdir(d, scratch);
        if (!de || errno != 0)
            break;

        if (gf_string2int(de->d_name, &pid) != -1 && pid >= 0) {
            ppid = pidinfo(pid, &name);
            switch (ppid) {
                case -1:
                    continue;
                case -2:
                    break;
            }
            ret = proch(pid, ppid, name, data);
            GF_FREE(name);
            if (ret)
                break;
        }
    }
    sys_closedir(d);
    if (!de && errno) {
        fprintf(stderr, "failed to traverse " PROC " (%s)\n", strerror(errno));
        ret = -1;
    }

    return ret;
}