From: Daiki Ueno <ueno@gnu.org>
Date: Sun, 20 Jul 2025 08:37:11 +0000 (+0900)
Subject: str: make gnutls_buffer resizing behavior configurable at run-time
X-Git-Tag: 3.8.11~30^2~14
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3ef04880a42874612cacdb42cfcbc33afbb2fa36;p=thirdparty%2Fgnutls.git

str: make gnutls_buffer resizing behavior configurable at run-time

Signed-off-by: Daiki Ueno <ueno@gnu.org>
---

diff --git a/lib/global.c b/lib/global.c
index 1f56b86ce8..feda32eb32 100644
--- a/lib/global.c
+++ b/lib/global.c
@@ -281,6 +281,14 @@ static int _gnutls_global_init(unsigned constructor)
 	bindtextdomain(PACKAGE, LOCALEDIR);
 #endif
 
+	e = secure_getenv("GNUTLS_BUFFER_RECLAIM");
+	if (e != NULL) {
+		bool reclaiming = e[0] == '1' && e[1] == '\0';
+		_gnutls_debug_log("Using %s buffer allocator...\n",
+				  reclaiming ? "reclaiming" : "non-reclaiming");
+		_gnutls_buffer_set_reclaiming(reclaiming);
+	}
+
 	res = gnutls_crypto_init();
 	if (res != 0) {
 		gnutls_assert();
diff --git a/lib/str.c b/lib/str.c
index 9865db7315..c6f879685e 100644
--- a/lib/str.c
+++ b/lib/str.c
@@ -128,15 +128,13 @@ int gnutls_buffer_append_data(gnutls_buffer_t dest, const void *data,
 	return 0;
 }
 
-#ifdef AGGRESSIVE_REALLOC
-
 /* Use a simpler logic for reallocation; i.e., always call
  * gnutls_realloc_fast() and do not reclaim the no-longer-used
  * area which has been removed from the beginning of buffer
  * with _gnutls_buffer_pop_datum().  This helps hit more
  * issues when running under valgrind.
  */
-int _gnutls_buffer_resize(gnutls_buffer_st *dest, size_t new_size)
+static int buffer_resize_no_reclaim(gnutls_buffer_st *dest, size_t new_size)
 {
 	size_t unused;
 
@@ -155,8 +153,6 @@ int _gnutls_buffer_resize(gnutls_buffer_st *dest, size_t new_size)
 	return 0;
 }
 
-#else
-
 static void align_allocd_with_data(gnutls_buffer_st *dest)
 {
 	assert(dest->allocd != NULL);
@@ -166,7 +162,7 @@ static void align_allocd_with_data(gnutls_buffer_st *dest)
 	dest->data = dest->allocd;
 }
 
-int _gnutls_buffer_resize(gnutls_buffer_st *dest, size_t new_size)
+static int buffer_resize_reclaim(gnutls_buffer_st *dest, size_t new_size)
 {
 	if (unlikely(dest->data != NULL && dest->allocd == NULL))
 		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
@@ -197,7 +193,14 @@ int _gnutls_buffer_resize(gnutls_buffer_st *dest, size_t new_size)
 	}
 }
 
-#endif
+int (*_gnutls_buffer_resize)(gnutls_buffer_st *,
+			     size_t) = buffer_resize_reclaim;
+
+void _gnutls_buffer_set_reclaiming(bool reclaiming)
+{
+	_gnutls_buffer_resize = reclaiming ? buffer_resize_reclaim :
+					     buffer_resize_no_reclaim;
+}
 
 /* Appends the provided string. The null termination byte is appended
  * but not included in length.
diff --git a/lib/str.h b/lib/str.h
index bc4272ca84..4e305c4200 100644
--- a/lib/str.h
+++ b/lib/str.h
@@ -111,7 +111,9 @@ inline static ATTRIBUTE_NONNULL() gnutls_buffer_st
 	return dst;
 }
 
-int _gnutls_buffer_resize(gnutls_buffer_st *, size_t new_size);
+void _gnutls_buffer_set_reclaiming(bool reclaiming);
+
+extern int (*_gnutls_buffer_resize)(gnutls_buffer_st *, size_t);
 
 int _gnutls_buffer_append_str(gnutls_buffer_st *, const char *str);