From 4fdfa3177ecd4853e0e32adfa6c107e3a66e91e2 Mon Sep 17 00:00:00 2001
From: George Koehler <kernigh@gmail.com>
Date: Mon, 12 Nov 2018 22:46:26 -0500
Subject: [PATCH] Fix em_led -u name when memory allocator moves ALLOMODL.

Option -u was passing an offset from modulptr(0) in ALLOMODL to the
string in argv.  If entername() would move ALLOMODL to make room in
ALLOGCHR, then the offset would become invalid, so the string would
get lost.  This fix copies the string into ALLOMODL.

This was often not a problem because the initial size of ALLOGCHR in
mach.h is probably large enough for -u.  This became a problem when I
caused the initial allocations to fail, and then only because the B
runtime uses -u.
---
 util/led/main.c | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/util/led/main.c b/util/led/main.c
index 7e7ce6d54..24bff403f 100644
--- a/util/led/main.c
+++ b/util/led/main.c
@@ -15,6 +15,7 @@ static char rcsid[] = "$Id$";
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdbool.h>
+#include <string.h>
 #include <out.h>
 #include "const.h"
 #include "debug.h"
@@ -36,7 +37,7 @@ static			first_pass();
 static uint32_t		number(const char *);
 static void		setlign(int, uint32_t);
 static void		setbase(int, uint32_t);
-static struct outname	*makename();
+static void		enterundef(const char *, int);
 static			pass1();
 static			evaluate();
 static void		norm_commons();
@@ -129,8 +130,6 @@ first_pass(argv)
 	register char		*argp;
 	int			sectno;
 	int			h;
-	extern int		atoi();
-	extern char		*strchr();
 	extern int		hash();
 	extern struct outname	*searchname();
 
@@ -235,7 +234,7 @@ first_pass(argv)
 				fatal("-u needs symbol name");
 			h = hash(*argv);
 			if (searchname(*argv, h) == (struct outname *)0)
-				entername(makename(*argv), h);
+				enterundef(*argv, h);
 			break;
 		case 'v':
 			Verbose = 1;
@@ -330,17 +329,34 @@ setbase(int sectno, uint32_t base)
 	sect_base[sectno] = base;
 }
 
-static struct outname *
-makename(string)
-	char	*string;
+/*
+ * Do -u name by entering the undefined name in the symbol table.
+ */
+static void
+enterundef(const char *string, int hashval)
 {
-	static struct outname	namebuf;
+	struct outname	namebuf;
+	size_t		len;
+	char		*buf;
 
-	namebuf.on_foff = string - core_position - mems[ALLOMODL].mem_base;
+	/*
+	 * Copy string to ALLOMODL, because entername() uses
+	 * modulptr(namebuf.on_foff) but may move ALLOMODL to make
+	 * room in ALLOGCHR.  It also needs namebuf.on_foff != 0.
+	 */
+	len = strlen(string) + 1;
+	buf = core_alloc(ALLOMODL, 1 + len);
+	if (buf == NULL)
+		fatal("no space for -u %s", string);
+	memcpy(buf + 1, string, len);
+
+	namebuf.on_foff = buf + 1 - modulptr(0);
 	namebuf.on_type = S_UND + S_EXT;
 	namebuf.on_valu = (long)0;
+	entername(&namebuf, hashval);
 
-	return &namebuf;
+	/* buf might have moved; find it again and free it. */
+	core_free(ALLOMODL, modulptr(namebuf.on_foff) - 1);
 }
 
 /*