/*	$OpenBSD: util.c,v 1.19 2009/10/27 23:59:22 deraadt Exp $	*/
/*	$NetBSD: util.c,v 1.2 1995/03/21 08:19:08 cgd Exp $	*/

/*-
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  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 University 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 REGENTS 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 REGENTS 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 <sys/param.h>
#include <sys/stat.h>
#include <sys/wait.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdarg.h>

#include "extern.h"

static pid_t do_cmd_pid = -1; /* PID of subprocess during do_local_cmd() */

char *
colon(char *cp)
{
	for (; *cp; ++cp) {
		if (*cp == ':')
			return (cp);
		if (*cp == '/')
			return (0);
	}
	return (0);
}

void
verifydir(char *cp)
{
	struct stat stb;

	if (!stat(cp, &stb)) {
		if (S_ISDIR(stb.st_mode))
			return;
		errno = ENOTDIR;
	}
	run_err("%s: %s", cp, strerror(errno));
	exit(1);
}

int
okname(char *cp0)
{
	int c;
	char *cp;

	cp = cp0;
	do {
		c = *cp;
		if (c & 0200)
			goto bad;
		if (!isalpha(c) && !isdigit(c) && c != '_' && c != '-')
			goto bad;
	} while (*++cp);
	return (1);

bad:	warnx("%s: invalid user name", cp0);
	return (0);
}

BUF *
allocbuf(BUF *bp, int fd, int blksize)
{
	struct stat stb;
	size_t size;
	char *p;

	if (fstat(fd, &stb) < 0) {
		run_err("fstat: %s", strerror(errno));
		return (0);
	}
	size = roundup(stb.st_blksize, blksize);
	if (size == 0)
		size = blksize;
	if (bp->cnt >= size)
		return (bp);
	if ((p = realloc(bp->buf, size)) == NULL) {
		free(bp->buf);
		bp->buf = NULL;
		bp->cnt = 0;
		run_err("%s", strerror(errno));
		return (0);
	}
	memset(p, 0, size);
	bp->buf = p;
	bp->cnt = size;
	return (bp);
}

/* ARGSUSED */
void
lostconn(int signo)
{
	extern char *__progname;
	char buf[1024];

	if (!iamremote) {
		strlcpy(buf, __progname, sizeof buf);
		strlcat(buf, ": lost connection\n", sizeof buf);
		write(STDERR_FILENO, buf, strlen(buf));
	}
	_exit(1);
}


static void
killchild(int signo)
{
	if (do_cmd_pid > 1) {
		kill(do_cmd_pid, signo ? signo : SIGTERM);
		waitpid(do_cmd_pid, NULL, 0);
	}

	if (signo)
		_exit(1);
	exit(1);
}

int
do_local_cmd(arglist *a, uid_t userid, gid_t groupid)
{
	int status;
	pid_t pid;

	if (a->num == 0)
		errx(1, "do_local_cmd: no arguments");

	if ((pid = fork()) == -1)
		err(1, "do_local_cmd: fork");

	if (pid == 0) {
		setresgid(groupid, groupid, groupid);
		setgroups(1, &groupid);
		setresuid(userid, userid, userid);
		execvp(a->list[0], a->list);
		perror(a->list[0]);
		exit(1);
	}

	do_cmd_pid = pid;
	signal(SIGTERM, killchild);
	signal(SIGINT, killchild);
	signal(SIGHUP, killchild);

	while (waitpid(pid, &status, 0) == -1)
		if (errno != EINTR)
			err(1, "do_local_cmd: waitpid");

	do_cmd_pid = -1;

	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
		return (-1);

	signal(SIGTERM, SIG_DFL);
	signal(SIGINT, SIG_DFL);
	signal(SIGHUP, SIG_DFL);

	return (0);
}

/* function to assist building execv() arguments */
void
addargs(arglist *args, char *fmt, ...)
{
	va_list ap;
	char *cp;
	u_int nalloc;
	int r;

	va_start(ap, fmt);
	r = vasprintf(&cp, fmt, ap);
	va_end(ap);
	if (r == -1)
		errx(1, "addargs: argument too long");

	nalloc = args->nalloc;
	if (args->list == NULL) {
		nalloc = 32;
		args->num = 0;
	} else if (args->num+2 >= nalloc)
		nalloc *= 2;

	if ((args->list = realloc(args->list, nalloc * sizeof(char *))) == NULL)
		errx(1, "addargs: realloc failed");
	args->nalloc = nalloc;
	args->list[args->num++] = cp;
	args->list[args->num] = NULL;
}

void
freeargs(arglist *args)
{
	u_int i;

	if (args->list != NULL) {
		for (i = 0; i < args->num; i++)
			free(args->list[i]);
		free(args->list);
		args->nalloc = args->num = 0;
		args->list = NULL;
	}
}