/*
 * Copyright (c) 1998 - 2001, 2004 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <config.h>

#include <stdarg.h>
#include <stdlib.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <errno.h>

#include "roken.h"

#define EX_NOEXEC       126
#define EX_NOTFOUND     127

/* return values:
   SE_E_UNSPECIFIED   on `unspecified' system errors
   SE_E_FORKFAILED    on fork failures
   SE_E_WAITPIDFAILED on waitpid errors
   SE_E_EXECTIMEOUT   exec timeout
   0-   is return value from subprocess
   SE_E_NOEXEC        if the program couldn't be executed
   SE_E_NOTFOUND      if the program couldn't be found
   128- is 128 + signal that killed subprocess

   possible values `func' can return:
   ((time_t)-2)         exit loop w/o killing child and return
                        `exec timeout'/-4 from simple_exec
   ((time_t)-1)         kill child with SIGTERM and wait for child to exit
   0                    don't timeout again
   n                    seconds to next timeout
   */

static int sig_alarm;

static RETSIGTYPE
sigtimeout(int sig)
{
    sig_alarm = 1;
    SIGRETURN(0);
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
wait_for_process_timed(pid_t pid, time_t (*func)(void *),
                       void *ptr, time_t timeout)
{
    RETSIGTYPE (*old_func)(int sig) = NULL;
    unsigned int oldtime = 0;
    int ret;

    sig_alarm = 0;

    if (func) {
        old_func = signal(SIGALRM, sigtimeout);
        oldtime = alarm(timeout);
    }

    while(1) {
        int status;

        while(waitpid(pid, &status, 0) < 0) {
            if (errno != EINTR) {
                ret = SE_E_WAITPIDFAILED;
                goto out;
            }
            if (func == NULL)
                continue;
            if (sig_alarm == 0)
                continue;
            timeout = (*func)(ptr);
            if (timeout == (time_t)-1) {
                kill(pid, SIGTERM);
                continue;
            } else if (timeout == (time_t)-2) {
                ret = SE_E_EXECTIMEOUT;
                goto out;
            }
            alarm(timeout);
        }
        if(WIFSTOPPED(status))
            continue;
        if(WIFEXITED(status)) {
            ret = WEXITSTATUS(status);
            break;
        }
        if(WIFSIGNALED(status)) {
            ret = WTERMSIG(status) + 128;
            break;
        }
    }
 out:
    if (func) {
        signal(SIGALRM, old_func);
        alarm(oldtime);
    }
    return ret;
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
wait_for_process(pid_t pid)
{
    return wait_for_process_timed(pid, NULL, NULL, 0);
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
pipe_execv(FILE **stdin_fd, FILE **stdout_fd, FILE **stderr_fd,
           const char *file, ...)
{
    int in_fd[2], out_fd[2], err_fd[2];
    pid_t pid;
    va_list ap;
    char **argv;

    if(stdin_fd != NULL)
        pipe(in_fd);
    if(stdout_fd != NULL)
        pipe(out_fd);
    if(stderr_fd != NULL)
        pipe(err_fd);
    pid = fork();
    switch(pid) {
    case 0:
        va_start(ap, file);
        argv = vstrcollect(&ap);
        va_end(ap);
        if(argv == NULL)
            exit(-1);

        /* close pipes we're not interested in */
        if(stdin_fd != NULL)
            close(in_fd[1]);
        if(stdout_fd != NULL)
            close(out_fd[0]);
        if(stderr_fd != NULL)
            close(err_fd[0]);

        /* pipe everything caller doesn't care about to /dev/null */
        if(stdin_fd == NULL)
            in_fd[0] = open(_PATH_DEVNULL, O_RDONLY);
        if(stdout_fd == NULL)
            out_fd[1] = open(_PATH_DEVNULL, O_WRONLY);
        if(stderr_fd == NULL)
            err_fd[1] = open(_PATH_DEVNULL, O_WRONLY);

        /* move to proper descriptors */
        if(in_fd[0] != STDIN_FILENO) {
            dup2(in_fd[0], STDIN_FILENO);
            close(in_fd[0]);
        }
        if(out_fd[1] != STDOUT_FILENO) {
            dup2(out_fd[1], STDOUT_FILENO);
            close(out_fd[1]);
        }
        if(err_fd[1] != STDERR_FILENO) {
            dup2(err_fd[1], STDERR_FILENO);
            close(err_fd[1]);
        }

        closefrom(3);

        execv(file, argv);
        exit((errno == ENOENT) ? EX_NOTFOUND : EX_NOEXEC);
    case -1:
        if(stdin_fd != NULL) {
            close(in_fd[0]);
            close(in_fd[1]);
        }
        if(stdout_fd != NULL) {
            close(out_fd[0]);
            close(out_fd[1]);
        }
        if(stderr_fd != NULL) {
            close(err_fd[0]);
            close(err_fd[1]);
        }
        return SE_E_FORKFAILED;
    default:
        if(stdin_fd != NULL) {
            close(in_fd[0]);
            *stdin_fd = fdopen(in_fd[1], "w");
        }
        if(stdout_fd != NULL) {
            close(out_fd[1]);
            *stdout_fd = fdopen(out_fd[0], "r");
        }
        if(stderr_fd != NULL) {
            close(err_fd[1]);
            *stderr_fd = fdopen(err_fd[0], "r");
        }
    }
    return pid;
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
simple_execvp_timed(const char *file, char *const args[],
                    time_t (*func)(void *), void *ptr, time_t timeout)
{
    pid_t pid = fork();
    switch(pid){
    case -1:
        return SE_E_FORKFAILED;
    case 0:
        execvp(file, args);
        exit((errno == ENOENT) ? EX_NOTFOUND : EX_NOEXEC);
    default:
        return wait_for_process_timed(pid, func, ptr, timeout);
    }
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
simple_execvp(const char *file, char *const args[])
{
    return simple_execvp_timed(file, args, NULL, NULL, 0);
}

/* gee, I'd like a execvpe */
ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
simple_execve_timed(const char *file, char *const args[], char *const envp[],
                    time_t (*func)(void *), void *ptr, time_t timeout)
{
    pid_t pid = fork();
    switch(pid){
    case -1:
        return SE_E_FORKFAILED;
    case 0:
        execve(file, args, envp);
        exit((errno == ENOENT) ? EX_NOTFOUND : EX_NOEXEC);
    default:
        return wait_for_process_timed(pid, func, ptr, timeout);
    }
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
simple_execve(const char *file, char *const args[], char *const envp[])
{
    return simple_execve_timed(file, args, envp, NULL, NULL, 0);
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
simple_execlp(const char *file, ...)
{
    va_list ap;
    char **argv;
    int ret;

    va_start(ap, file);
    argv = vstrcollect(&ap);
    va_end(ap);
    if(argv == NULL)
        return SE_E_UNSPECIFIED;
    ret = simple_execvp(file, argv);
    free(argv);
    return ret;
}

ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
simple_execle(const char *file, ... /* ,char *const envp[] */)
{
    va_list ap;
    char **argv;
    char *const* envp;
    int ret;

    va_start(ap, file);
    argv = vstrcollect(&ap);
    envp = va_arg(ap, char **);
    va_end(ap);
    if(argv == NULL)
        return SE_E_UNSPECIFIED;
    ret = simple_execve(file, argv, envp);
    free(argv);
    return ret;
}