From 6d92af64de5e78ded1a7cb27a88d7e10c9f576a8 Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@systemlinux.org>
Date: Sun, 10 Jan 2010 18:40:40 +0100
Subject: [PATCH] stdin: Use buffer pools.

This introduces a memory leak to be fixed in a subsequent patch (the
buffer pool can not be freed in post_select() because there might
still be references to its area).
---
 stdin.c | 33 +++++++++++++++++++++------------
 stdin.h |  1 +
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/stdin.c b/stdin.c
index abe69caf..4329e144 100644
--- a/stdin.c
+++ b/stdin.c
@@ -95,11 +95,11 @@ static void stdin_post_select(struct sched *s, struct task *t)
 		t->error = -E_STDIN_EOF;
 }
 
-#define STDIN_INPUT_BUFFER_SIZE (1024 * 32)
 static void stdin_post_select_btr(struct sched *s, struct task *t)
 {
 	struct stdin_task *sit = container_of(t, struct stdin_task, task);
 	ssize_t ret;
+	size_t sz;
 	char *buf = NULL;
 
 	t->error = 0;
@@ -110,21 +110,29 @@ static void stdin_post_select_btr(struct sched *s, struct task *t)
 		return;
 	if (!FD_ISSET(STDIN_FILENO, &s->rfds))
 		return;
-	buf = para_malloc(STDIN_INPUT_BUFFER_SIZE);
-	ret = read(STDIN_FILENO, buf, STDIN_INPUT_BUFFER_SIZE);
+	sz = btr_pool_get_buffer(sit->btrp, &buf);
+	ret = -E_STDIN_OVERRUN;
+	if (sz == 0)
+		goto err;
+	/*
+	 * Do not use the maximal size to avoid having only a single buffer
+	 * reference for the whole pool. This is bad because if that single
+	 * reference can not be freed, we're stuck.
+	 */
+	sz = PARA_MIN(sz, btr_pool_size(sit->btrp) / 2);
+	ret = read(STDIN_FILENO, buf, sz);
 	//PARA_CRIT_LOG("read ret: %d\n", ret);
-	if (ret <= 0) {
-		if (ret < 0)
-			ret = -ERRNO_TO_PARA_ERROR(errno);
-		else
-			ret = -E_STDIN_EOF;
+	if (ret < 0)
+		ret = -ERRNO_TO_PARA_ERROR(errno);
+	if (ret == 0)
+		ret = -E_STDIN_EOF;
+	if (ret < 0)
 		goto err;
-	}
-	btr_add_output(buf, ret, sit->btrn);
+	btr_add_output_pool(sit->btrp, ret, sit->btrn);
 	return;
 err:
-	free(buf);
 	btr_remove_node(sit->btrn);
+	//btr_pool_free(sit->btrp);
 	t->error = ret;
 }
 
@@ -135,7 +143,7 @@ err:
  *
  * This fills in the pre/post select function pointers of the task structure
  * given by \a sit. Moreover, the stdin file desctiptor is set to nonblocking
- * mode and \a bufsize is initialized to 16 KB (but no buffer is allocated).
+ * mode and \a bufsize is initialized (but no buffer is allocated).
  */
 void stdin_set_defaults(struct stdin_task *sit)
 {
@@ -145,6 +153,7 @@ void stdin_set_defaults(struct stdin_task *sit)
 	if (sit->btrn) {
 		sit->task.pre_select = stdin_pre_select_btr;
 		sit->task.post_select = stdin_post_select_btr;
+		sit->btrp = btr_pool_new("stdin", 64 * 1024);
 	} else {
 		sit->task.pre_select = stdin_pre_select;
 		sit->task.post_select = stdin_post_select;
diff --git a/stdin.h b/stdin.h
index 8e5b3ce5..2b87f760 100644
--- a/stdin.h
+++ b/stdin.h
@@ -22,6 +22,7 @@ struct stdin_task {
 	struct task task;
 	/** Non-null if buffer tree API should be used. */
 	struct btr_node *btrn;
+	struct btr_pool *btrp;
 };
 
 void stdin_set_defaults(struct stdin_task *sit);
-- 
2.39.5