hush: implement `type`

Implement support for the POSIX `type` command.  Only POSIX stuff is
supported here, no bash extensions like -p or -P.

In the process, split the $PATH searching code out of builtin_source() and
into its own find_in_path() function so we don't duplicate it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

diff --git a/shell/hush.c b/shell/hush.c
index 7167de701f53a6bec875e4a52503559b77c231d4..efa93c1a6c22d94e1b39f70f542cea3d25707aec 100644 (file)
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -539,6 +539,7 @@ static int builtin_shift(char **argv);
 static int builtin_source(char **argv);
 static int builtin_test(char **argv);
 static int builtin_trap(char **argv);
+static int builtin_type(char **argv);
 static int builtin_true(char **argv);
 static int builtin_umask(char **argv);
 static int builtin_unset(char **argv);
@@ -610,6 +611,7 @@ static const struct built_in_command bltins[] = {
        BLTIN("shift"   , builtin_shift   , "Shift positional parameters"),
        BLTIN("test"    , builtin_test    , "Test condition"),
        BLTIN("trap"    , builtin_trap    , "Trap signals"),
+       BLTIN("type"    , builtin_type    , "Write a description of command type"),
 //     BLTIN("ulimit"  , builtin_return  , "Control resource limits"),
        BLTIN("umask"   , builtin_umask   , "Set file creation mask"),
        BLTIN("unset"   , builtin_unset   , "Unset environment variable"),
@@ -2865,6 +2867,39 @@ static struct pipe *parse_stream(char **pstring,
 static void parse_and_run_string(const char *s);
 
 
+static char *find_in_path(const char *arg)
+{
+       char *ret = NULL;
+       const char *PATH = get_local_var_value("PATH");
+
+       if (!PATH)
+               return NULL;
+
+       while (1) {
+               const char *end = strchrnul(PATH, ':');
+               int sz = end - PATH; /* must be int! */
+
+               free(ret);
+               if (sz != 0) {
+                       ret = xasprintf("%.*s/%s", sz, PATH, arg);
+               } else {
+                       /* We have xxx::yyyy in $PATH,
+                        * it means "use current dir" */
+                       ret = xstrdup(arg);
+               }
+               if (access(ret, F_OK) == 0)
+                       break;
+
+               if (*end == '\0') {
+                       free(ret);
+                       return NULL;
+               }
+               PATH = end + 1;
+       }
+
+       return ret;
+}
+
 static const struct built_in_command* find_builtin(const char *name)
 {
        const struct built_in_command *x;
@@ -6728,6 +6763,43 @@ static int builtin_trap(char **argv)
        goto process_sig_list;
 }
 
+/* http://www.opengroup.org/onlinepubs/9699919799/utilities/type.html */
+static int builtin_type(char **argv)
+{
+       int i, ret = EXIT_SUCCESS;
+
+       for (i = 1; argv[i]; ++i) {
+               void *path;
+               const void *find_ret;
+               const char *type;
+
+               type = path = NULL;
+
+               if (0) {} /* make conditional compile easier below */
+               /*else if ((find_ret = find_alias(argv[i])))
+                       type = "an alias";*/
+#if ENABLE_HUSH_FUNCTIONS
+               else if ((find_ret = find_function(argv[i])))
+                       type = "a function";
+#endif
+               else if ((find_ret = find_builtin(argv[i])))
+                       type = "a shell builtin";
+               else if ((find_ret = path = find_in_path(argv[i])))
+                       type = find_ret;
+
+               if (!type) {
+                       bb_error_msg("type: %s: not found", argv[i]);
+                       ret = EXIT_FAILURE;
+               } else
+                       printf("%s is %s\n", argv[i], type);
+
+               if (path)
+                       free(path);
+       }
+
+       return ret;
+}
+
 #if ENABLE_HUSH_JOB
 /* built-in 'fg' and 'bg' handler */
 static int builtin_fg_bg(char **argv)
@@ -6986,7 +7058,7 @@ static int builtin_shift(char **argv)
 
 static int builtin_source(char **argv)
 {
-       const char *PATH;
+       char *arg_path;
        FILE *input;
        save_arg_t sv;
 #if ENABLE_HUSH_FUNCTIONS
@@ -6996,36 +7068,15 @@ static int builtin_source(char **argv)
        if (*++argv == NULL)
                return EXIT_FAILURE;
 
-       if (strchr(*argv, '/') == NULL
-        && (PATH = get_local_var_value("PATH")) != NULL
-       ) {
-               /* Search through $PATH */
-               while (1) {
-                       const char *end = strchrnul(PATH, ':');
-                       int sz = end - PATH; /* must be int! */
-
-                       if (sz != 0) {
-                               char *tmp = xasprintf("%.*s/%s", sz, PATH, *argv);
-                               input = fopen_for_read(tmp);
-                               free(tmp);
-                       } else {
-                               /* We have xxx::yyyy in $PATH,
-                                * it means "use current dir" */
-                               input = fopen_for_read(*argv);
-                       }
-                       if (input)
-                               goto opened_ok;
-                       if (*end == '\0')
-                               break;
-                       PATH = end + 1;
-               }
-       }
-       input = fopen_or_warn(*argv, "r");
+       if (strchr(*argv, '/') == NULL && (arg_path = find_in_path(*argv)) != NULL) {
+               input = fopen_for_read(arg_path);
+               free(arg_path);
+       } else
+               input = fopen_or_warn(*argv, "r");
        if (!input) {
                /* bb_perror_msg("%s", *argv); - done by fopen_or_warn */
                return EXIT_FAILURE;
        }
- opened_ok:
        close_on_exec_on(fileno(input));
 
 #if ENABLE_HUSH_FUNCTIONS