[PATCH v2 11/20] trace-cmd library: Read compression header

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx>]

Trace file version 7 introduced new mandatory compression header,
storing information about the compression algorithm used to compress the
trace file. Added code to read that header and to initialize compression
context according to it.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
 lib/trace-cmd/trace-input.c | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index 41b60649..d4728c86 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -189,6 +189,7 @@ __thread struct tracecmd_input *tracecmd_curr_thread_handle;
 
 #define CHECK_READ_STATE(H, S) ((H)->file_version < FILE_VERSION_SECTIONS && (H)->file_state >= (S))
 #define HAS_SECTIONS(H) ((H)->flags & TRACECMD_FL_SECTIONED)
+#define HAS_COMPRESSION(H) ((H)->flags & TRACECMD_FL_COMPRESSION)
 
 static int read_options_type(struct tracecmd_input *handle);
 
@@ -3797,7 +3798,9 @@ struct tracecmd_input *tracecmd_alloc_fd(int fd, int flags)
 	char test[] = TRACECMD_MAGIC;
 	unsigned int page_size;
 	size_t offset;
-	char *version;
+	char *version = NULL;
+	char *zver = NULL;
+	char *zname = NULL;
 	char buf[BUFSIZ];
 	unsigned long ver;
 
@@ -3835,9 +3838,12 @@ struct tracecmd_input *tracecmd_alloc_fd(int fd, int flags)
 	}
 	handle->file_version = ver;
 	free(version);
+	version = NULL;
 
 	if (handle->file_version >= FILE_VERSION_SECTIONS)
 		handle->flags |= TRACECMD_FL_SECTIONED;
+	if (handle->file_version >= FILE_VERSION_COMPRESSION)
+		handle->flags |= TRACECMD_FL_COMPRESSION;
 
 	if (do_read_check(handle, buf, 1))
 		goto failed_read;
@@ -3867,6 +3873,26 @@ struct tracecmd_input *tracecmd_alloc_fd(int fd, int flags)
 	handle->total_file_size = lseek64(handle->fd, 0, SEEK_END);
 	lseek64(handle->fd, offset, SEEK_SET);
 
+	if (HAS_COMPRESSION(handle)) {
+		zname = read_string(handle);
+		if (!zname)
+			goto failed_read;
+		zver = read_string(handle);
+		if (!zver)
+			goto failed_read;
+		if (strcmp(zname, "none")) {
+			handle->compress = tracecmd_compress_alloc(zname, zver,
+								   handle->fd,
+								   handle->pevent, NULL);
+			if (!handle->compress) {
+				tracecmd_warning("Unsupported file compression %s %s", zname, zver);
+				goto failed_read;
+			}
+		}
+		free(zname);
+		free(zver);
+	}
+
 	if (HAS_SECTIONS(handle)) {
 		if (read8(handle, &(handle->options_start))) {
 			tracecmd_warning("Filed to read the offset of the first option section");
@@ -3879,6 +3905,9 @@ struct tracecmd_input *tracecmd_alloc_fd(int fd, int flags)
 	return handle;
 
  failed_read:
+	free(version);
+	free(zname);
+	free(zver);
 	free(handle);
 
 	return NULL;
@@ -4077,7 +4106,8 @@ void tracecmd_close(struct tracecmd_input *handle)
 	if (handle->flags & TRACECMD_FL_BUFFER_INSTANCE)
 		tracecmd_close(handle->parent);
 	else {
-		/* Only main handle frees plugins and pevent */
+		/* Only main handle frees plugins, pevent and compression context */
+		tracecmd_compress_destroy(handle->compress);
 		tep_unload_plugins(handle->plugin_list, handle->pevent);
 		tep_free(handle->pevent);
 	}
-- 
2.31.1