BSD 4_3_Net_1 release

[unix-history] / lib / libc / gen / getusershell.c

/*
* Copyright (c) 1985 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley.  The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getusershell.c      5.5 (Berkeley) 7/21/88";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <ctype.h>
#include <stdio.h>

#define SHELLS "/etc/shells"

/*
* Do not add local shells here.  They should be added in /etc/shells
*/
static char *okshells[] =
   { "/bin/sh", "/bin/csh", 0 };

static char **shells, *strings;
static char **curshell = NULL;
extern char **initshells();

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

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

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

setusershell()
{

       curshell = initshells();
}

static char **
initshells()
{
       register char **sp, *cp;
       register FILE *fp;
       struct stat statb;
       extern char *malloc(), *calloc();

       if (shells != NULL)
               free((char *)shells);
       shells = NULL;
       if (strings != NULL)
               free(strings);
       strings = NULL;
       if ((fp = fopen(SHELLS, "r")) == (FILE *)0)
               return(okshells);
       if (fstat(fileno(fp), &statb) == -1) {
               (void)fclose(fp);
               return(okshells);
       }
       if ((strings = malloc((unsigned)statb.st_size)) == NULL) {
               (void)fclose(fp);
               return(okshells);
       }
       shells = (char **)calloc((unsigned)statb.st_size / 3, sizeof (char *));
       if (shells == NULL) {
               (void)fclose(fp);
               free(strings);
               strings = NULL;
               return(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);
}