/*	$NetBSD: run.c,v 1.14 2009/03/04 18:22:14 christos Exp $	*/

/*
 * Copyright (c) 1991 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator   or   Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the rights
 * to redistribute these changes.
 */
/*  run, runv, runp, runvp --  execute process and wait for it to exit
 *
 *  Usage:
 *	i = run (file, arg1, arg2, ..., argn, 0);
 *	i = runv (file, arglist);
 *	i = runp (file, arg1, arg2, ..., argn, 0);
 *	i = runvp (file, arglist);
 *	i = runio (argv, in, out, err);
 *
 *  Run, runv, runp and runvp have argument lists exactly like the
 *  corresponding routines, execl, execv, execlp, execvp.  The run
 *  routines perform a fork, then:
 *  IN THE NEW PROCESS, an execl[p] or execv[p] is performed with the
 *  specified arguments.  The process returns with a -1 code if the
 *  exec was not successful.
 *  IN THE PARENT PROCESS, the signals SIGQUIT and SIGINT are disabled,
 *  the process waits until the newly forked process exits, the
 *  signals are restored to their original status, and the return
 *  status of the process is analyzed.
 *  All run routines return:  -1 if the exec failed or if the child was
 *  terminated abnormally; otherwise, the exit code of the child is
 *  returned.
 *
 **********************************************************************
 * HISTORY
 * Revision 1.1  89/10/14  19:53:39  rvb
 * Initial revision
 *
 * Revision 1.2  89/08/03  14:36:46  mja
 * 	Update run() and runp() to use <varargs.h>.
 * 	[89/04/19            mja]
 *
 * 23-Sep-86  Glenn Marcy (gm0w) at Carnegie-Mellon University
 *	Merged old runv and runvp modules.
 *
 * 22-Nov-85  Glenn Marcy (gm0w) at Carnegie-Mellon University
 *	Added check and kill if child process was stopped.
 *
 * 30-Apr-85  Steven Shafer (sas) at Carnegie-Mellon University
 *	Adapted for 4.2 BSD UNIX:  Conforms to new signals and wait.
 *
 * 15-July-82 Mike Accetta (mja) and Neal Friedman (naf)
 *				  at Carnegie-Mellon University
 *	Added a return(-1) if vfork fails.  This should only happen
 *	if there are no more processes available.
 *
 * 28-Jan-80  Steven Shafer (sas) at Carnegie-Mellon University
 *	Added setuid and setgid for system programs' use.
 *
 * 21-Jan-80  Steven Shafer (sas) at Carnegie-Mellon University
 *	Changed fork to vfork.
 *
 * 20-Nov-79  Steven Shafer (sas) at Carnegie-Mellon University
 *	Created for VAX.  The proper way to fork-and-execute a system
 *	program is now by "runvp" or "runp", with the program name
 *	(rather than an absolute pathname) as the first argument;
 *	that way, the "PATH" variable in the environment does the right
 *	thing.  Too bad execvp and execlp (hence runvp and runp) don't
 *	accept a pathlist as an explicit argument.
 *
 **********************************************************************
 */

#include <stdio.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/wait.h>

#include "supcdefs.h"
#include "supextern.h"

static int dorun(char *, char **, int);
static char **makearglist(va_list);

static char **
makearglist(va_list ap)
{
	static size_t ns = 0;
	static char **np = NULL;
	char **nnp;
	size_t i = 0;

	do {
		if (i >= ns) {
			nnp = realloc(np, (ns + 20) * sizeof(*np));
			if (nnp == NULL) {
				free(np);
				return NULL;
			}
			np = nnp;
			ns += 20;
		}
		np[i] = va_arg(ap, char *);
	}
	while (np[i++] != NULL);
	return np;
}

int
run(char *name, ...)
{
	int val;
	va_list ap;
	char **argv;

	va_start(ap, name);
	if ((argv = makearglist(ap)) == NULL) {
		va_end(ap);
		return -1;
	}
	val = runv(name, argv);
	va_end(ap);
	return (val);
}

int 
runv(char *name, char **argv)
{
	return (dorun(name, argv, 0));
}

int
runp(char *name, ...)
{
	int val;
	va_list ap;
	char **argv;

	va_start(ap, name);
	if ((argv = makearglist(ap)) == NULL) {
		va_end(ap);
		return -1;
	}
	val = runvp(name, argv);
	va_end(ap);
	return (val);
}

int 
runvp(char *name, char **argv)
{
	return (dorun(name, argv, 1));
}

static int 
dorun(char *name, char **argv, int usepath)
{
	int wpid;
	int pid;
	struct sigaction ignoresig, intsig, quitsig;
	int status;

	if ((pid = vfork()) == -1)
		return (-1);	/* no more processes, so exit with error */

	if (pid == 0) {		/* child process */
		setgid(getgid());
		setuid(getuid());
		if (usepath)
			execvp(name, argv);
		else
			execv(name, argv);
		fprintf(stderr, "run: can't exec %s (%s)\n", name,
		    strerror(errno));
		_exit(0377);
	}
	ignoresig.sa_handler = SIG_IGN;	/* ignore INT and QUIT signals */
	sigemptyset(&ignoresig.sa_mask);
	ignoresig.sa_flags = 0;
	sigaction(SIGINT, &ignoresig, &intsig);
	sigaction(SIGQUIT, &ignoresig, &quitsig);
	do {
		wpid = wait3(&status, WUNTRACED, 0);
		if (WIFSTOPPED(status)) {
			kill(0, SIGTSTP);
			wpid = 0;
		}
	} while (wpid != pid && wpid != -1);
	sigaction(SIGINT, &intsig, 0);	/* restore signals */
	sigaction(SIGQUIT, &quitsig, 0);

	if (WIFSIGNALED(status) || WEXITSTATUS(status) == 0377)
		return (-1);

	return (WEXITSTATUS(status));
}

/*
 * Like system(3), but with an argument list and explicit redirections
 * that does not use the shell
 */
int
runio(char *const * argv, const char *infile, const char *outfile,
      const char *errfile)
{
	int fd;
	pid_t pid;
	int status;

	switch ((pid = fork())) {
	case -1:
		return -1;

	case 0:
		if (infile) {
			(void) close(0);
			if ((fd = open(infile, O_RDONLY)) == -1)
				exit(1);
			if (fd != 0)
				(void) dup2(fd, 0);
		}
		if (outfile) {
			(void) close(1);
			if ((fd = open(outfile, O_RDWR | O_CREAT | O_TRUNC,
				    0666)) == -1)
				exit(1);
			if (fd != 1)
				(void) dup2(fd, 1);
		}
		if (errfile) {
			(void) close(2);
			if ((fd = open(errfile, O_RDWR | O_CREAT | O_TRUNC,
				    0666)) == -1)
				exit(1);
			if (fd != 2)
				(void) dup2(fd, 2);
		}
		execvp(argv[0], argv);
		exit(1);
		/* NOTREACHED */
		return 0;

	default:
		if (waitpid(pid, &status, 0) == -1)
			return -1;
		return status;
	}
}

/*
 * Like runio, but works with filedescriptors instead of filenames
 */
int
runiofd(char *const * argv, const int infile, const int outfile,
	const int errfile)
{
	pid_t pid;
	int status;

	switch ((pid = fork())) {
	case -1:
		return -1;

	case 0:
		if (infile != 0)
			dup2(infile, 0);
		if (outfile != 1)
			dup2(outfile, 1);
		if (errfile != 2)
			dup2(errfile, 2);
		execvp(argv[0], argv);
		exit(1);
		/* NOTREACHED */
		return 0;

	default:
		if (waitpid(pid, &status, 0) == -1)
			return -1;
		return status;
	}
}