From: Pierre-Marc Fournier <pierre-marc.fournier@polymtl.ca>
Date: Fri, 12 Feb 2010 00:21:04 +0000 (-0500)
Subject: fix support for trace format 2.5
X-Git-Tag: v0.2~21
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=02af3e607f471e9fcfe7ea6902cab56efb4c4516;p=ust.git

fix support for trace format 2.5
---

diff --git a/libust/buffers.c b/libust/buffers.c
index 33c9589..a36453d 100644
--- a/libust/buffers.c
+++ b/libust/buffers.c
@@ -307,7 +307,9 @@ static void ltt_buffer_begin(struct ust_buffer *buf,
 				subbuf_idx * buf->chan->subbuf_size);
 
 	header->cycle_count_begin = tsc;
-	header->data_size = 0xFFFFFFFF; /* for debugging */
+	header->data_size = 0xFFFFFFFF; /* for recognizing crashed buffers */
+	header->sb_size = 0xFFFFFFFF; /* for recognizing crashed buffers */
+	/* FIXME: add memory barrier? */
 	ltt_write_trace_header(channel->trace, header);
 }
 
diff --git a/ustd/lowlevel.c b/ustd/lowlevel.c
index bce1d20..d8d4cfa 100644
--- a/ustd/lowlevel.c
+++ b/ustd/lowlevel.c
@@ -16,6 +16,7 @@
  */
 
 #include <assert.h>
+#include <byteswap.h>
 
 #include "buffers.h"
 #include "tracer.h"
@@ -26,6 +27,40 @@
 #define USTD_BUFFER_TRUNC(offset, bufinfo) \
 	((offset) & (~(((bufinfo)->subbuf_size*(bufinfo)->n_subbufs)-1)))
 
+#define LTT_MAGIC_NUMBER 0x00D6B7ED
+#define LTT_REV_MAGIC_NUMBER 0xEDB7D600
+
+/* Returns the size of a subbuffer size. This is the size that
+ * will need to be written to disk.
+ *
+ * @subbuffer: pointer to the beginning of the subbuffer (the
+ *             beginning of its header)
+ */
+
+size_t subbuffer_data_size(void *subbuf)
+{
+	struct ltt_subbuffer_header *header = subbuf;
+	int reverse;
+	u32 data_size;
+
+	if(header->magic_number == LTT_MAGIC_NUMBER) {
+		reverse = 0;
+	}
+	else if(header->magic_number == LTT_REV_MAGIC_NUMBER) {
+		reverse = 1;
+	}
+	else {
+		return -1;
+	}
+
+	data_size = header->sb_size;
+	if(reverse)
+		data_size = bswap_32(data_size);
+
+	return data_size;
+}
+
+
 void finish_consuming_dead_subbuffer(struct buffer_info *buf)
 {
 	struct ust_buffer *ustbuf = buf->bufstruct_mem;
@@ -68,6 +103,8 @@ void finish_consuming_dead_subbuffer(struct buffer_info *buf)
 
 		struct ltt_subbuffer_header *header = (struct ltt_subbuffer_header *)((char *)buf->mem+i_subbuf*buf->subbuf_size);
 
+		int pad_size;
+
 		if((commit_seq & commit_seq_mask) == 0) {
 			/* There is nothing to do. */
 			/* FIXME: is this needed? */
@@ -76,8 +113,8 @@ void finish_consuming_dead_subbuffer(struct buffer_info *buf)
 
 		/* Check if subbuf was fully written. This is from Mathieu's algorithm/paper. */
 		if (((commit_seq - buf->subbuf_size) & commit_seq_mask)
-		    - (USTD_BUFFER_TRUNC(consumed_offset, buf) >> n_subbufs_order)
-		    == 0) {
+		    - (USTD_BUFFER_TRUNC(consumed_offset, buf) >> n_subbufs_order) == 0
+                    && header->data_size != 0xffffffff && header->sb_size != 0xffffffff) {
 			/* If it was, we only check the data_size. This is the amount of valid data at
 			 * the beginning of the subbuffer. */
 			valid_length = header->data_size;
@@ -90,6 +127,7 @@ void finish_consuming_dead_subbuffer(struct buffer_info *buf)
 
 			valid_length = commit_seq & (buf->subbuf_size-1);
 			header->data_size = valid_length;
+			header->sb_size = PAGE_ALIGN(valid_length);
 			assert(i_subbuf == (last_subbuf % buf->n_subbufs));
 		}
 
@@ -97,10 +135,13 @@ void finish_consuming_dead_subbuffer(struct buffer_info *buf)
 		patient_write(buf->file_fd, buf->mem + i_subbuf * buf->subbuf_size, valid_length);
 
 		/* pad with empty bytes */
-		tmp = malloc(buf->subbuf_size-valid_length);
-		memset(tmp, 0, buf->subbuf_size-valid_length);
-		patient_write(buf->file_fd, tmp, buf->subbuf_size-valid_length);
-		free(tmp);
+		pad_size = PAGE_ALIGN(valid_length)-valid_length;
+		if(pad_size) {
+			tmp = malloc(pad_size);
+			memset(tmp, 0, pad_size);
+			patient_write(buf->file_fd, tmp, pad_size);
+			free(tmp);
+		}
 
 		if(i_subbuf == last_subbuf % buf->n_subbufs)
 			break;
diff --git a/ustd/ustd.c b/ustd/ustd.c
index 969c192..21da4eb 100644
--- a/ustd/ustd.c
+++ b/ustd/ustd.c
@@ -359,6 +359,24 @@ struct buffer_info *connect_buffer(pid_t pid, const char *bufname)
 	return buf;
 }
 
+int write_current_subbuffer(struct buffer_info *buf)
+{
+	int result;
+
+	void *subbuf_mem = buf->mem + (buf->consumed_old & (buf->n_subbufs * buf->subbuf_size-1));
+
+	size_t cur_sb_size = subbuffer_data_size(subbuf_mem);
+
+	result = patient_write(buf->file_fd, subbuf_mem, cur_sb_size);
+	if(result == -1) {
+		PERROR("write");
+		/* FIXME: maybe drop this trace */
+		return 0;
+	}
+
+	return 0;
+}
+
 int consumer_loop(struct buffer_info *buf)
 {
 	int result;
@@ -382,11 +400,8 @@ int consumer_loop(struct buffer_info *buf)
 		}
 
 		/* write data to file */
-		result = patient_write(buf->file_fd, buf->mem + (buf->consumed_old & (buf->n_subbufs * buf->subbuf_size-1)), buf->subbuf_size);
-		if(result == -1) {
-			PERROR("write");
-			/* FIXME: maybe drop this trace */
-		}
+		write_current_subbuffer(buf);
+		/* FIXME: handle return value? */
 
 		/* put the subbuffer */
 		/* FIXME: we actually should unput the buffer before consuming... */
diff --git a/ustd/ustd.h b/ustd/ustd.h
index 8d5becd..5be186a 100644
--- a/ustd/ustd.h
+++ b/ustd/ustd.h
@@ -33,5 +33,6 @@ struct buffer_info {
 };
 
 void finish_consuming_dead_subbuffer(struct buffer_info *buf);
+size_t subbuffer_data_size(void *subbuf);
 
 #endif /* USTD_H */