port/gen/getusershell.c

	getusershell.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */


/*
 * Copyright (c) 1985 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#include "synonyms.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <ctype.h>
#include <stdio.h>
#include <limits.h>
#include <stdlib.h>
#include <sys/file.h>
#include "libc.h"
#include <unistd.h>

#define SHELLS "/etc/shells"

/*
 * Do not add local shells here.  They should be added in /etc/shells
 */
const char *okshells[] = {
    "/usr/bin/sh",
    "/usr/bin/csh",
    "/usr/bin/ksh",
    "/usr/bin/jsh",
    "/bin/sh",
    "/bin/csh",
    "/bin/ksh",
    "/bin/jsh",
    "/sbin/sh",
    "/sbin/jsh",
    "/usr/bin/pfsh",
    "/usr/bin/pfcsh",
    "/usr/bin/pfksh",
    "/usr/bin/bash",
    "/usr/bin/tcsh",
    "/usr/bin/zsh",
    "/bin/pfsh",
    "/bin/pfcsh",
    "/bin/pfksh",
    "/bin/bash",
    "/bin/tcsh",
    "/bin/zsh",
    "/usr/xpg4/bin/sh",
    "/sbin/pfsh",
    NULL
};

static char **shells, *strings;
static char **curshell;
static char **initshells(void);

/*
 * Get a list of shells from SHELLS, if it exists.
 */
char *
getusershell(void)
{
    char *ret;

    if (curshell == NULL)
        curshell = initshells();
    ret = *curshell;
    if (ret != NULL)
        curshell++;
    return (ret);
}

void
endusershell(void)
{

    if (shells != NULL)
        (void) free((char *)shells);
    shells = NULL;
    if (strings != NULL)
        (void) free(strings);
    strings = NULL;
    curshell = NULL;
}

void
setusershell(void)
{

    curshell = initshells();
}

static char **
initshells(void)
{
    char **sp, *cp;
    FILE *fp;
    struct stat statb;

    if (shells != NULL)
        (void) free((char *)shells);
    shells = NULL;
    if (strings != NULL)
        (void) free(strings);
    strings = NULL;
    if ((fp = fopen(SHELLS, "r")) == (FILE *)0)
        return ((char **)okshells);
    /*
     * The +1 in the malloc() below is needed to handle the final
     * fgets() NULL terminator.  From fgets(3S):
     *
     * char *fgets(char *s, int n, FILE *stream);
     *
     * The  fgets()  function reads characters from the stream into
     * the array pointed to by s, until n-1 characters are read, or
     * a newline character is read and transferred to s, or an end-
     * of-file condition is encountered.  The string is then termi-
     * nated with a null character.
     */
    if ((fstat(fileno(fp), &statb) == -1) || (statb.st_size > LONG_MAX) ||
        ((strings = malloc((size_t)statb.st_size + 1)) == NULL)) {
        (void) fclose(fp);
        return ((char **)okshells);
    }
    shells = calloc((size_t)statb.st_size / 3, sizeof (char *));
    if (shells == NULL) {
        (void) fclose(fp);
        (void) free(strings);
        strings = NULL;
        return ((char **)okshells);
    }
    sp = shells;
    cp = strings;
    while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
        while (*cp != '#' && *cp != '/' && *cp != '\0')
            cp++;
        if (*cp == '#' || *cp == '\0')
            continue;
        *sp++ = cp;
        while (!isspace(*cp) && *cp != '#' && *cp != '\0')
            cp++;
        *cp++ = '\0';
    }
    *sp = (char *)0;
    (void) fclose(fp);
    return (shells);
}