chsh: cleanup global_shells usage

* global variables are always initialized by NULL
* it seems we need it as global variable due to libreadline, then use it as
  global everywhere in the same .c file.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/login-utils/chsh.c b/login-utils/chsh.c
index 7d67493a46aa92de1c1f1eadcd1c1eb52dcb3b02..3bea971cdc513fd5b3ca860eb24333d31ee754fd 100644 (file)
--- a/login-utils/chsh.c
+++ b/login-utils/chsh.c
@@ -68,7 +68,7 @@ struct sinfo {
 };
 
 /* global due readline completion */
-static char **global_shells = NULL;
+static char **global_shells;
 
 static void __attribute__((__noreturn__)) usage (FILE *fp)
 {
@@ -93,27 +93,34 @@ static void __attribute__((__noreturn__)) usage (FILE *fp)
  */
 static void free_shells(void)
 {
-       char **s;
+       if (global_shells) {
+               char **s;
 
-       for (s = global_shells; *s; s++)
-               free(*s);
-       free(global_shells);
+               for (s = global_shells; *s; s++)
+                       free(*s);
+               free(global_shells);
+       }
 }
 
 /*
- *  init_shells () -- fill shells variable from /etc/shells,
+ *  init_shells () -- reads /etc/shells into global_shells
  */
-static int init_shells(char ***shells)
+static int init_shells(void)
 {
        FILE *fp;
        char *buf = NULL;
        size_t sz = 0, shellsz = 8, n = 0;
        ssize_t len;
 
-       *shells = xmalloc(sizeof(char *) * shellsz);
+       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)
@@ -121,17 +128,20 @@ static int init_shells(char ***shells)
                /* strip the ending newline */
                if (buf[len - 1] == '\n')
                        buf[len - 1] = 0;
-               (*shells)[n++] = buf;
+               global_shells[n++] = buf;
                if (shellsz < n) {
                        shellsz *= 2;
-                       shells = xrealloc(shells, sizeof(char *) * shellsz);
+                       global_shells = xrealloc(global_shells, sizeof(char *) * shellsz);
                }
                buf = NULL;
        }
+
        free(buf);
-       (*shells)[n] = NULL;
+       global_shells[n] = NULL;
+
        fclose(fp);
        atexit(free_shells);
+
        return 0;
 }
 
@@ -139,14 +149,14 @@ static int init_shells(char ***shells)
  *  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 ***shells)
+static int is_known_shell(const char *shell_name)
 {
        char **s;
 
-       if (!shells || !shell_name)
+       if (!global_shells || !shell_name)
                return 0;
 
-       for (s = *shells; *s; s++) {
+       for (s = global_shells; *s; s++) {
                if (strcmp(shell_name, *s) == 0)
                        return 1;
        }
@@ -156,14 +166,14 @@ static int is_known_shell(const char *shell_name, char ***shells)
 /*
  *  print_shells () -- /etc/shells is outputted to stdout.
  */
-static void print_shells(char ***shells)
+static void print_shells(void)
 {
        char **s;
 
-       if (!shells)
+       if (!global_shells)
                return;
 
-       for (s = *shells; *s; s++)
+       for (s = global_shells; *s; s++)
                printf("%s\n", *s);
 }
 
@@ -173,6 +183,9 @@ static char *shell_name_generator(const char *text, int state)
        static size_t len, idx;
        char *s;
 
+       if (!global_shells)
+               return NULL;
+
        if (!state) {
                idx = 0;
                len = strlen(text);
@@ -198,7 +211,7 @@ static char **shell_name_completion(const char *text,
  *     parse the command line arguments, and fill in "pinfo" with any
  *     information from the command line.
  */
-static void parse_argv(int argc, char **argv, struct sinfo *pinfo, char ***shells)
+static void parse_argv(int argc, char **argv, struct sinfo *pinfo)
 {
        static const struct option long_options[] = {
                {"shell",       required_argument, NULL, 's'},
@@ -218,8 +231,8 @@ static void parse_argv(int argc, char **argv, struct sinfo *pinfo, char ***shell
                case 'h':
                        usage(stdout);
                case 'l':
-                       init_shells(shells);
-                       print_shells(shells);
+                       init_shells();
+                       print_shells();
                        exit(EXIT_SUCCESS);
                case 's':
                        if (!optarg)
@@ -272,7 +285,7 @@ static char *ask_new_shell(char *question, char *oldshell)
  *  check_shell () -- if the shell is completely invalid, print
  *     an error and exit.
  */
-static void check_shell(const char *shell, char ***shells)
+static void check_shell(const char *shell)
 {
        if (*shell != '/')
                errx(EXIT_FAILURE, _("shell must be a full path name"));
@@ -282,7 +295,7 @@ static void check_shell(const char *shell, char ***shells)
                errx(EXIT_FAILURE, _("\"%s\" is not executable"), shell);
        if (illegal_passwd_chars(shell))
                errx(EXIT_FAILURE, _("%s: has illegal characters"), shell);
-       if (!is_known_shell(shell, shells)) {
+       if (!is_known_shell(shell)) {
 #ifdef ONLY_LISTED_SHELLS
                if (!getuid())
                        warnx(_("Warning: \"%s\" is not listed in %s."), shell,
@@ -314,7 +327,7 @@ int main(int argc, char **argv)
        textdomain(PACKAGE);
        atexit(close_stdout);
 
-       parse_argv(argc, argv, &info, &global_shells);
+       parse_argv(argc, argv, &info);
        if (!info.username) {
                pw = getpwuid(uid);
                if (!pw)
@@ -373,8 +386,8 @@ int main(int argc, char **argv)
                    _("running UID doesn't match UID of user we're "
                      "altering, shell change denied"));
        }
-       init_shells(&global_shells);
-       if (uid != 0 && !is_known_shell(oldshell, &global_shells)) {
+       init_shells();
+       if (uid != 0 && !is_known_shell(oldshell)) {
                errno = EACCES;
                err(EXIT_FAILURE, _("your shell is not in %s, "
                                    "shell change denied"), _PATH_SHELLS);
@@ -393,7 +406,7 @@ int main(int argc, char **argv)
                        return EXIT_SUCCESS;
        }
 
-       check_shell(info.shell, &global_shells);
+       check_shell(info.shell);
 
        if (!nullshell && strcmp(oldshell, info.shell) == 0)
                errx(EXIT_SUCCESS, _("Shell not changed."));