gen/common/execvp.c

	execvp.c revision 5d54f3d8999eac1762fe0a8c7177d20f1f201fae
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984 AT&T */
/*        All Rights Reserved   */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*LINTLIBRARY*/
/*
 *  execlp(name, arg,...,0) (like execl, but does path search)
 *  execvp(name, argv)  (like execv, but does path search)
 */
#include <errno.h>
#include <sys/param.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

static char *execat(char *, char *, char *);
static char *shell = "/bin/sh";

int
execlp(char *name, ...)
{
    va_list args;
    int r;

    va_start(args, name);
    r = execvp(name, (char **)args);
    va_end(args);

    return (r);
}

int
execvp(char *name, char **argv)
{
    char    *pathstr;
    char    fname[MAXPATHLEN];
    char    *newargs[256];
    int i;
    char    *cp;
    unsigned etxtbsy = 1;
    int eacces = 0;

    if ((pathstr = getenv("PATH")) == NULL)
        pathstr = ":/usr/ucb:/bin:/usr/bin";
    cp = strchr(name, '/') ? "": pathstr;

    do {
        cp = execat(cp, name, fname);
    retry:
        (void) execv(fname, argv);
        switch (errno) {
        case ENOEXEC:
            newargs[0] = "sh";
            newargs[1] = fname;
            for (i = 1; (newargs[i+1] = argv[i]) != NULL; ++i) {
                if (i >= 254) {
                    errno = E2BIG;
                    return(-1);
                }
            }
            (void) execv(shell, newargs);
            return (-1);
        case ETXTBSY:
            if (++etxtbsy > 5)
                return (-1);
            (void) sleep(etxtbsy);
            goto retry;
        case EACCES:
            ++eacces;
            break;
        case ENOMEM:
        case E2BIG:
        case EFAULT:
            return (-1);
        }
    } while (cp);
    if (eacces)
        errno = EACCES;
    return (-1);
}

static char *
execat(char *s1, char *s2, char *si)
{
    char    *s;
    char    *end;

    s = si;
    end = s + MAXPATHLEN;
    while (*s1 && *s1 != ':' && s < end)
        *s++ = *s1++;
    if (si != s && s < end)
        *s++ = '/';
    while (*s2 && s < end)
        *s++ = *s2++;
    *s = '\0';
    return (*s1 ? ++s1: 0);
}