From 926ebb68acc6d24980e2a8e90383d21636657012 Mon Sep 17 00:00:00 2001
From: Robert Spalek <robert@ucw.cz>
Date: Fri, 25 Jun 2004 16:37:50 +0000
Subject: [PATCH] added lizard_realloc() to avoid restoring and reestablishing
 SIGSEGv handler

---
 lib/lizard-safe.c | 19 ++++++++++++++++---
 lib/lizard.h      |  1 +
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/lib/lizard-safe.c b/lib/lizard-safe.c
index 1c46cbdc..4e07036a 100644
--- a/lib/lizard-safe.c
+++ b/lib/lizard-safe.c
@@ -18,16 +18,22 @@
 #include <setjmp.h>
 #include <errno.h>
 
-struct lizard_buffer *
-lizard_alloc(uns max_len)
+static void
+lizard_alloc_internal(struct lizard_buffer *buf, uns max_len)
 {
-  struct lizard_buffer *buf = xmalloc(sizeof(struct lizard_buffer));
   buf->len = ALIGN(max_len + 3, PAGE_SIZE);		// +3 due to the unaligned access
   buf->start = mmap(NULL, buf->len + PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
   if (buf->start == MAP_FAILED)
     die("mmap(anonymous): %m");
   if (mprotect(buf->start + buf->len, PAGE_SIZE, PROT_NONE) < 0)
     die("mprotect: %m");
+}
+
+struct lizard_buffer *
+lizard_alloc(uns max_len)
+{
+  struct lizard_buffer *buf = xmalloc(sizeof(struct lizard_buffer));
+  lizard_alloc_internal(buf, max_len);
   buf->old_sigsegv_handler = xmalloc(sizeof(struct sigaction));
   handle_signal(SIGSEGV, buf->old_sigsegv_handler);
   return buf;
@@ -42,6 +48,13 @@ lizard_free(struct lizard_buffer *buf)
   xfree(buf);
 }
 
+void
+lizard_realloc(struct lizard_buffer *buf, uns max_len)
+{
+  munmap(buf->start, buf->len + PAGE_SIZE);
+  lizard_alloc_internal(buf, max_len);
+}
+
 static jmp_buf safe_decompress_jump;
 static int
 sigsegv_handler(int signal UNUSED)
diff --git a/lib/lizard.h b/lib/lizard.h
index fc3631ac..3f72b96c 100644
--- a/lib/lizard.h
+++ b/lib/lizard.h
@@ -37,4 +37,5 @@ struct lizard_buffer {
 
 struct lizard_buffer *lizard_alloc(uns max_len);
 void lizard_free(struct lizard_buffer *buf);
+void lizard_realloc(struct lizard_buffer *buf, uns max_len);
 int lizard_decompress_safe(byte *in, struct lizard_buffer *buf, uns expected_length);
-- 
2.39.2