hush: document better where bad redirect syntax is detected

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 20 insertions, 3 deletions

diff --git a/shell/hush.c b/shell/hush.c
index a8ec54ec0..e2b0a15b8 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -3054,6 +3054,14 @@ static int done_command(struct parse_context *ctx)
         struct pipe *pi = ctx->pipe;
         struct command *command = ctx->command;
 
+#if 0   /* Instead we emit error message at run time */
+        if (ctx->pending_redirect) {
+                /* For example, "cmd >" (no filename to redirect to) */
+                die_if_script("syntax error: %s", "invalid redirect");
+                ctx->pending_redirect = NULL;
+        }
+#endif
+
         if (command) {
                 if (IS_NULL_CMD(command)) {
                         debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
@@ -3576,6 +3584,12 @@ static int parse_redirect(struct parse_context *ctx,
                 debug_printf_parse("duplicating redirect '%d>&%d'\n",
                                 redir->rd_fd, redir->rd_dup);
         } else {
+#if 0           /* Instead we emit error message at run time */
+                if (ctx->pending_redirect) {
+                        /* For example, "cmd > <file" */
+                        die_if_script("syntax error: %s", "invalid redirect");
+                }
+#endif
                 /* Set ctx->pending_redirect, so we know what to do at the
                  * end of the next parsed word. */
                 ctx->pending_redirect = redir;
@@ -6276,9 +6290,12 @@ static int setup_redirects(struct command *prog, int squirrel[])
                         /* "rd_fd<*>file" case (<*> is <,>,>>,<>) */
                         char *p;
                         if (redir->rd_filename == NULL) {
-                                /* Something went wrong in the parse.
-                                 * Pretend it didn't happen */
-                                bb_error_msg("bug in redirect parse");
+                                /*
+                                 * Examples:
+                                 * "cmd >" (no filename)
+                                 * "cmd > <file" (2nd redirect starts too early)
+                                 */
+                                die_if_script("syntax error: %s", "invalid redirect");
                                 continue;
                         }
                         mode = redir_table[redir->rd_type].mode;