check_rc_readproc.c

/* Copyright (C) 2009 Trend Micro Inc.
 * All right reserved.
 *
 * This program is a free software; you can redistribute it
 * and/or modify it under the terms of the GNU General Public
 * License (version 2) as published by the FSF - Free Software
 * Foundation
 */

#ifndef WIN32

#include "shared.h"
#include "rootcheck.h"

#define PROC 0
#define PID  1
#define TASK 2

/* Prototypes */
static int read_proc_file(const char *file_name, const char *pid, int position);
static int read_proc_dir(const char *dir_name, const char *pid, int position);

/* Global variables */
static int proc_pid_found;


static int read_proc_file(const char *file_name, const char *pid, int position)
{
    struct stat statbuf;

    if (lstat(file_name, &statbuf) < 0) {
        return (-1);
    }

    /* If directory, read the directory */
    if (S_ISDIR(statbuf.st_mode)) {
        return (read_proc_dir(file_name, pid, position));
    }

    return (0);
}

int read_proc_dir(const char *dir_name, const char *pid, int position)
{
    DIR *dp;
    struct dirent *entry;

    if ((dir_name == NULL) || (strlen(dir_name) > PATH_MAX)) {
        merror("%s: Invalid directory given", ARGV0);
        return (-1);
    }

    /* Open the directory */
    dp = opendir(dir_name);
    if (!dp) {
        return (0);
    }

    while ((entry = readdir(dp)) != NULL) {
        char f_name[PATH_MAX + 2];

        /* Ignore . and ..  */
        if (strcmp(entry->d_name, ".")  == 0 ||
                strcmp(entry->d_name, "..") == 0) {
            continue;
        }

        if (position == PROC) {
            char *tmp_str;

            tmp_str = entry->d_name;
            while (*tmp_str != '\0') {
                if (!isdigit((int)*tmp_str)) {
                    break;
                }
                tmp_str++;
            }

            if (*tmp_str != '\0') {
                continue;
            }

            snprintf(f_name, PATH_MAX + 1, "%s/%s", dir_name, entry->d_name);
            read_proc_file(f_name, pid, position + 1);
        } else if (position == PID) {
            if (strcmp(entry->d_name, "task") == 0) {
                snprintf(f_name, PATH_MAX + 1, "%s/%s", dir_name, entry->d_name);
                read_proc_file(f_name, pid, position + 1);
            }
        } else if (position == TASK) {
            /* Check under proc/pid/task/lwp */
            if (strcmp(entry->d_name, pid) == 0) {
                proc_pid_found = 1;
                break;
            }
        } else {
            break;
        }
    }

    closedir(dp);

    return (0);
}

/*  Read the /proc directory (if present) and check if it can find
 *  the given pid (as a pid or as a thread)
 */
int check_rc_readproc(int pid)
{
    char char_pid[32];

    proc_pid_found = 0;

    /* NL threads */
    snprintf(char_pid, 31, "/proc/.%d", pid);
    if (is_file(char_pid)) {
        return (1);
    }

    snprintf(char_pid, 31, "%d", pid);
    read_proc_dir("/proc", char_pid, PROC);

    return (proc_pid_found);
}

#endif