getusershell.c revision 5d54f3d8999eac1762fe0a8c7177d20f1f201fae
/*
* Copyright (c) 1985 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sys/param.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <ctype.h>
#include <stdio.h>
#include <malloc.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", "/usr/bin/sh", "/usr/bin/csh", 0 };
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)
free((char *)shells);
shells = NULL;
if (strings != NULL)
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)
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 + 1)) == 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);
}