[PATCH 01/10] trace-cmd dump: Add helpers for processing trace file version 7

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

New global variables are added, that hold trace file context:
 - trace file version
 - compression context
Also a few helper functions for reading compressed data.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 tracecmd/trace-dump.c | 88 ++++++++++++++++++++++++++++++++-----------
 1 file changed, 67 insertions(+), 21 deletions(-)

diff --git a/tracecmd/trace-dump.c b/tracecmd/trace-dump.c
index 2334b57e..d0278f7e 100644
--- a/tracecmd/trace-dump.c
+++ b/tracecmd/trace-dump.c
@@ -26,6 +26,9 @@
 static struct tep_handle *tep;
 static unsigned int trace_cpus;
 static int has_clock;
+static unsigned long file_version;
+static bool	read_compress;
+static struct tracecmd_compression *compress;
 
 enum dump_items {
 	SUMMARY		= (1 << 0),
@@ -52,46 +55,69 @@ enum dump_items verbosity;
 			tracecmd_plog(fmt, ##__VA_ARGS__);	\
 	} while (0)
 
-static int read_file_string(int fd, char *dst, int len)
+static int read_fd(int fd, char *dst, int len)
 {
 	size_t size = 0;
 	int r;
 
 	do {
-		r = read(fd, dst+size, 1);
+		r = read(fd, dst+size, len);
 		if (r > 0) {
-			size++;
-			len--;
+			size += r;
+			len -= r;
 		} else
 			break;
-		if (!dst[size - 1])
-			break;
-	} while (r > 0 && len);
+	} while (r > 0);
 
-	if (!size || dst[size - 1])
+	if (len)
 		return -1;
-	return 0;
+	return size;
 }
 
-static int read_file_bytes(int fd, char *dst, int len)
+static int read_compressed(int fd, char *dst, int len)
+{
+
+	if (read_compress)
+		return tracecmd_compress_read(compress, dst, len);
+	return read_fd(fd, dst, len);
+}
+
+static int do_lseek(int fd, int offset, int whence)
+{
+	if (read_compress)
+		return tracecmd_compress_lseek(compress, offset, whence);
+	return lseek64(fd, offset, whence);
+}
+
+static int read_file_string(int fd, char *dst, int len)
 {
 	size_t size = 0;
 	int r;
 
 	do {
-		r = read(fd, dst+size, len);
+		r = read_compressed(fd, dst+size, 1);
 		if (r > 0) {
-			size += r;
-			len -= r;
+			size++;
+			len--;
 		} else
 			break;
-	} while (r > 0);
+		if (!dst[size - 1])
+			break;
+	} while (r > 0 && len);
 
-	if (len)
+	if (!size || dst[size - 1])
 		return -1;
 	return 0;
 }
 
+static int read_file_bytes(int fd, char *dst, int len)
+{
+	int ret;
+
+	ret = read_compressed(fd, dst, len);
+	return ret < 0 ? ret : 0;
+}
+
 static void read_dump_string(int fd, int size, enum dump_items id)
 {
 	char buf[DUMP_SIZE];
@@ -146,7 +172,6 @@ static void dump_initial_format(int fd)
 	char magic[] = TRACECMD_MAGIC;
 	char buf[DUMP_SIZE];
 	int val4;
-	unsigned long ver;
 
 	do_print(SUMMARY, "\t[Initial format]\n");
 
@@ -168,11 +193,11 @@ static void dump_initial_format(int fd)
 		die("no version string");
 
 	do_print(SUMMARY, "\t\t%s\t[Version]\n", buf);
-	ver = strtol(buf, NULL, 10);
-	if (!ver && errno)
+	file_version = strtol(buf, NULL, 10);
+	if (!file_version && errno)
 		die("Invalid file version string %s", buf);
-	if (!tracecmd_is_version_supported(ver))
-		die("Unsupported file version %lu", ver);
+	if (!tracecmd_is_version_supported(file_version))
+		die("Unsupported file version %lu", file_version);
 
 	/* get file endianness*/
 	if (read_file_bytes(fd, buf, 1))
@@ -234,6 +259,27 @@ static void dump_header_event(int fd)
 	read_dump_string(fd, size, HEAD_EVENT);
 }
 
+static void uncompress_reset(void)
+{
+	if (compress && file_version >= FILE_VERSION_COMPRESSION) {
+		read_compress = false;
+		tracecmd_compress_reset(compress);
+	}
+}
+
+static int uncompress_block(void)
+{
+	int ret = 0;
+
+	if (compress && file_version >= FILE_VERSION_COMPRESSION) {
+		ret = tracecmd_uncompress_block(compress);
+		if (!ret)
+			read_compress = true;
+
+	}
+	return ret;
+}
+
 static void dump_ftrace_events_format(int fd)
 {
 	unsigned long long size;
@@ -578,7 +624,7 @@ static void dump_options(int fd)
 		default:
 			do_print(OPTIONS, " %d %d\t[Unknown option, size - skipping]\n",
 				 option, size);
-			lseek64(fd, size, SEEK_CUR);
+			do_lseek(fd, size, SEEK_CUR);
 			break;
 		}
 	}
-- 
2.31.1