libc/unistd/usershell.c

   1 /* setusershell(), getusershell(), endusershell() for uClibc.
   2  *
   3  * Copyright (C) 2010 Bernhard Reutner-Fischer <uclibc@uclibc.org>
   4  *
   5  * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in
   6  * this tarball.
   7  */
   8 /* My manpage reads:
   9  * The  getusershell() function returns the next line from the file
  10  * /etc/shells, opening the file if necessary. The line should contain
  11  * the pathname of a valid user shell.  If /etc/shells does not exist
  12  * or is unreadable, getusershell() behaves as if /bin/sh and /bin/csh
  13  * were listed in the file.
  14  * The getusershell() function returns a NULL pointer on end-of-file.
  15  */
  16 #include <unistd.h>
  17 #include <stdlib.h>
  18 #include <paths.h>
  19 #include <string.h>
  20 #include "internal/parse_config.h"
  21
  22 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_UNIX98)
  23
  24 static const char * const defaultsh[] = { _PATH_BSHELL, _PATH_CSHELL, NULL};
  25 static char *shellb, **shells;
  26 static parser_t *shellp;
  27
  28 void endusershell(void)
  29 {
  30         if (shellp) {
  31                 shells = (char**) shellb;
  32                 while (shells && *shells) {
  33                         char*xxx = *shells++;
  34                         free(xxx);
  35                 }
  36                 config_close(shellp);
  37                 shellp = NULL;
  38         }
  39         free(shellb);
  40         shellb = NULL;
  41         shells = NULL;
  42 }
  43 libc_hidden_def(endusershell)
  44
  45 void setusershell(void)
  46 {
  47         endusershell();
  48         shellp = config_open(_PATH_SHELLS);
  49         if (shellp == NULL)
  50                 shells = (char **)defaultsh;
  51         else {
  52                 char **shell = NULL;
  53                 int pos = 0;
  54
  55                 while (config_read(shellp, &shell, 1, 1, "# \t", PARSE_NORMAL))
  56                 {
  57                         shellb = realloc(shellb, (pos + 2) * sizeof(char*));
  58                         shells = (char**) shellb + pos++;
  59                         *shells++ = strdup(*shell);
  60                         *shells = NULL;
  61
  62                 }
  63                 shells = (char **)shellb;
  64         }
  65 }
  66 libc_hidden_def(setusershell)
  67
  68 char *getusershell(void)
  69 {
  70         char *sh;
  71         if (shells == NULL)
  72                 setusershell();
  73         sh = *shells;
  74         if (sh)
  75                 shells++;
  76         return sh;
  77 }
  78 #endif