From 8e8d94a3e08d4cfa9cb817ae36fd4181edea84d2 Mon Sep 17 00:00:00 2001
From: Niels Provos <provos@gmail.com>
Date: Thu, 24 Sep 2009 22:18:19 +0000
Subject: [PATCH] Do not drop data from evbuffer when out of memory; reported
 by Jacek Masiulaniec

svn:r1436
---
 ChangeLog             |  1 +
 buffer.c              |  1 -
 test/regress_buffer.c | 31 +++++++++++++++++++++++++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index d005b214..ff45f1a5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -22,6 +22,7 @@ Changes in 2.0.3-alpha:
  o Do not allocate the maximum event queue for the epoll backend at startup.  Instead, start out accepting 32 events at a time, and double the queue's size when it seems that the OS is generating events faster than we're requesting them.  Saves up to 374K per epoll-based event_base.  Resolves bug 2839240.
  o Treat an event with a negative fd as valid but untriggerable by Libevent.  This is useful for applications that want to manually activate events.
  o Fix compilation on Android, which forgot to define fd_mask in its sys/select.h
+ o Do not drop data from evbuffer when out of memory; reported by Jacek Masiulaniec
  
 
 Changes in 2.0.2-alpha:
diff --git a/buffer.c b/buffer.c
index 370823e2..979bc7d0 100644
--- a/buffer.c
+++ b/buffer.c
@@ -1172,7 +1172,6 @@ evbuffer_readln(struct evbuffer *buffer, size_t *n_read_out,
 
 	if ((line = mm_malloc(n_to_copy+1)) == NULL) {
 		event_warn("%s: out of memory\n", __func__);
-		evbuffer_drain(buffer, n_to_copy + extra_drain);
 		goto done;
 	}
 
diff --git a/test/regress_buffer.c b/test/regress_buffer.c
index a6031a02..ff0b9722 100644
--- a/test/regress_buffer.c
+++ b/test/regress_buffer.c
@@ -403,6 +403,12 @@ test_evbuffer_add_file(void *ptr)
 }
 #endif
 
+static void *
+failing_malloc(size_t how_much)
+{
+	return NULL;
+}
+
 static void
 test_evbuffer_readln(void *ptr)
 {
@@ -586,6 +592,31 @@ test_evbuffer_readln(void *ptr)
 	evbuffer_validate(evb);
 	tt_assert(evbuffer_get_length(evb) == 0);
 
+	/* Test memory problem*/
+	s = "one line\ntwo line\nblue line";
+	evbuffer_add(evb_tmp, s, strlen(s));
+	evbuffer_validate(evb);
+	evbuffer_add_buffer(evb, evb_tmp);
+	evbuffer_validate(evb);
+
+	cp = evbuffer_readln(evb, &sz, EVBUFFER_EOL_LF);
+	tt_line_eq("one line");
+	free(cp); cp = NULL;
+	evbuffer_validate(evb);
+
+	/* the next call to readline should fail */
+	event_set_mem_functions(failing_malloc, realloc, free);
+	cp = evbuffer_readln(evb, &sz, EVBUFFER_EOL_LF);
+	tt_assert(cp == NULL);
+	evbuffer_validate(evb);
+
+	/* now we should get the next line back */
+	event_set_mem_functions(malloc, realloc, free);
+	cp = evbuffer_readln(evb, &sz, EVBUFFER_EOL_LF);
+	tt_line_eq("two line");
+	free(cp); cp = NULL;
+	evbuffer_validate(evb);
+
 	test_ok = 1;
  end:
 	evbuffer_free(evb);