From faa7d863fcdfe380a173cf7a005f481066bef703 Mon Sep 17 00:00:00 2001
From: Eric Andersen
Date: Wed, 21 Apr 2004 00:56:22 +0000
Subject: So I'm building a linux from scratch system, using a working script
 to do this that the _only_ change to is that gnu sed has been replaced with
 busybox sed. And ncurses' install phase hangs.  I trace it down, and it's
 trying to run gawk.  (Insert obligatory doubletake, but this is FSF code
 we're talking about, so...)

It turns out gawk shells out to sed, ala "sed -f /tmp/blah file.h".  The
/tmp/blah file is basically empty (it contains one character, a newline).  So
basically, gawk is using sed as "cat".  With gnu sed, it works like cat,
anyway.

With busybox sed, it tests if its command list is empty after parsing the
command line, and if the list is empty it takes the first file argument as a
sed command string, and if that leaves the file list empty it tries to read
the data to operate on from stdin.  (Hence the hang, since nothing's coming
in on stdin...)

It _should_ be testing whether there were any instances of -f or -e, not
whether it actually got any commands.  Using sed as cat may be kind of
stupid, but it's valid and gawk relies on this behavior.

Here's a patch to fix it, turning a couple of ints into chars in hopes of
saving a bit of the space this adds.  Comments?

Rob
---
 editors/sed.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/editors/sed.c b/editors/sed.c
index 4b13925..968d0d2 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -1096,7 +1096,7 @@ static void add_cmd_block(char *cmdstr)
 
 extern int sed_main(int argc, char **argv)
 {
-	int opt, status = EXIT_SUCCESS;
+	char opt, getpat=1, status = EXIT_SUCCESS;
 
 #ifdef CONFIG_FEATURE_CLEAN_UP
 	/* destroy command strings on exit */
@@ -1124,6 +1124,7 @@ extern int sed_main(int argc, char **argv)
 			break;
 		case 'e':
 			add_cmd_block(optarg);
+			getpat=0;
 			break;
 		case 'f':
 		{
@@ -1135,6 +1136,7 @@ extern int sed_main(int argc, char **argv)
 			while ((line = bb_get_chomped_line_from_file(cmdfile))
 				 != NULL) {
 				add_cmd(line);
+				getpat=0;
 				free(line);
 			}
 			bb_xprint_and_close_file(cmdfile);
@@ -1148,7 +1150,7 @@ extern int sed_main(int argc, char **argv)
 
 	/* if we didn't get a pattern from a -e and no command file was specified,
 	 * argv[optind] should be the pattern. no pattern, no worky */
-	if (sed_cmd_head.next == NULL) {
+	if(getpat) {
 		if (argv[optind] == NULL)
 			bb_show_usage();
 		else
-- 
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