chsh: remove local /etc/shells parsing in favour of getusershell(3)

Less code, less bugs.  And if there are bugs at least share them with all
other programs that use getusershell(3) from libc.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/login-utils/chsh.c b/login-utils/chsh.c
index 4721c870e2b32fac217385241de58bc73b0b5f0d..c267c727283fc15e85e1000df6eeb49568d70966 100644 (file)
--- a/login-utils/chsh.c
+++ b/login-utils/chsh.c
@@ -67,9 +67,6 @@ struct sinfo {
        char *shell;
 };
 
-/* global due readline completion */
-static char **global_shells;
-
 static void __attribute__((__noreturn__)) usage(void)
 {
        FILE *fp = stdout;
@@ -89,79 +86,26 @@ static void __attribute__((__noreturn__)) usage(void)
        exit(EXIT_SUCCESS);
 }
 
-/*
- *  free_shells () -- free shells allocations.
- */
-static void free_shells(void)
-{
-       if (global_shells) {
-               char **s;
-
-               for (s = global_shells; *s; s++)
-                       free(*s);
-               free(global_shells);
-       }
-}
-
-/*
- *  init_shells () -- reads /etc/shells into global_shells
- */
-static int init_shells(void)
-{
-       FILE *fp;
-       char *buf = NULL;
-       size_t sz = 0, shellsz = 8, n = 0;
-       ssize_t len;
-
-       if (global_shells)
-               return 0;       /* already initialized */
-
-       fp = fopen(_PATH_SHELLS, "r");
-       if (!fp)
-               return 1;
-
-       global_shells = xmalloc(sizeof(char *) * shellsz);
-
-       while ((len = getline(&buf, &sz, fp)) != -1) {
-               /* ignore comments and blank lines */
-               if (*buf == '#' || len < 2)
-                       continue;
-               /* strip the ending newline */
-               if (buf[len - 1] == '\n')
-                       buf[len - 1] = 0;
-               global_shells[n++] = buf;
-               if (shellsz < n) {
-                       shellsz *= 2;
-                       global_shells = xrealloc(global_shells, sizeof(char *) * shellsz);
-               }
-               buf = NULL;
-       }
-
-       free(buf);
-       global_shells[n] = NULL;
-
-       fclose(fp);
-       atexit(free_shells);
-
-       return 0;
-}
-
 /*
  *  is_known_shell() -- if the given shell appears in /etc/shells,
  *     return true.  if not, return false.
  */
 static int is_known_shell(const char *shell_name)
 {
-       char **s;
+       char *s, ret = 0;
 
-       if (!global_shells || !shell_name)
+       if (!shell_name)
                return 0;
 
-       for (s = global_shells; *s; s++) {
-               if (strcmp(shell_name, *s) == 0)
-                       return 1;
+       setusershell();
+       while ((s = getusershell())) {
+               if (strcmp(shell_name, s) == 0) {
+                       ret = 1;
+                       break;
+               }
        }
-       return 0;
+       endusershell();
+       return ret;
 }
 
 /*
@@ -169,29 +113,25 @@ static int is_known_shell(const char *shell_name)
  */
 static void print_shells(void)
 {
-       char **s;
-
-       if (!global_shells)
-               return;
+       char *s;
 
-       for (s = global_shells; *s; s++)
-               printf("%s\n", *s);
+       while ((s = getusershell()))
+               printf("%s\n", s);
+       endusershell();
 }
 
 #ifdef HAVE_LIBREADLINE
 static char *shell_name_generator(const char *text, int state)
 {
-       static size_t len, idx;
+       static size_t len;
        char *s;
 
-       if (!global_shells)
-               return NULL;
-
        if (!state) {
-               idx = 0;
+               setusershell();
                len = strlen(text);
        }
-       while ((s = global_shells[idx++])) {
+
+       while ((s = getusershell())) {
                if (strncmp(s, text, len) == 0)
                        return xstrdup(s);
        }
@@ -232,7 +172,6 @@ static void parse_argv(int argc, char **argv, struct sinfo *pinfo)
                case 'h':
                        usage();
                case 'l':
-                       init_shells();
                        print_shells();
                        exit(EXIT_SUCCESS);
                case 's':
@@ -386,7 +325,6 @@ int main(int argc, char **argv)
                    _("running UID doesn't match UID of user we're "
                      "altering, shell change denied"));
        }
-       init_shells();
        if (uid != 0 && !is_known_shell(oldshell)) {
                errno = EACCES;
                err(EXIT_FAILURE, _("your shell is not in %s, "