[PATCH 20/25] trace-cmd library: Initialize CPU data for reading from version 7 trace files

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

In version 7 trace files, CPU trace data is written in slightly
different way than in version 6 files. Added new CPU data initialization
flow, to handle version 7 files:
 - the top trace instance is saved in the same way as the other trace
   instances.
 - per CPU trace metadata is stored in the buffer option.
 - trace data section has section header.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-input.c | 178 +++++++++++++++++++++++++-----------
 1 file changed, 123 insertions(+), 55 deletions(-)

diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index 5e33efa6..7ba08e5e 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -3203,34 +3203,18 @@ static int read_options_type(struct tracecmd_input *handle)
 	return 0;
 }
 
-static int read_cpu_data(struct tracecmd_input *handle)
+static int init_cpu_data(struct tracecmd_input *handle)
 {
-	struct tep_handle *pevent = handle->pevent;
 	enum kbuffer_long_size long_size;
 	enum kbuffer_endian endian;
-	unsigned long long size;
 	unsigned long long max_size = 0;
 	unsigned long long pages;
-	int cpus;
 	int cpu;
 
-	/*
-	 * Check if this is a latency report or not.
-	 */
-	if (handle->file_state == TRACECMD_FILE_CPU_LATENCY)
-		return 1;
-
 	/* We expect this to be flyrecord */
 	if (handle->file_state != TRACECMD_FILE_CPU_FLYRECORD)
 		return -1;
 
-	cpus = handle->cpus;
-
-	handle->cpu_data = malloc(sizeof(*handle->cpu_data) * handle->cpus);
-	if (!handle->cpu_data)
-		return -1;
-	memset(handle->cpu_data, 0, sizeof(*handle->cpu_data) * handle->cpus);
-
 	if (force_read)
 		handle->read_page = true;
 
@@ -3245,32 +3229,14 @@ static int read_cpu_data(struct tracecmd_input *handle)
 		endian = KBUFFER_ENDIAN_LITTLE;
 
 	for (cpu = 0; cpu < handle->cpus; cpu++) {
-		unsigned long long offset;
-
-		handle->cpu_data[cpu].cpu = cpu;
-
 		handle->cpu_data[cpu].kbuf = kbuffer_alloc(long_size, endian);
 		if (!handle->cpu_data[cpu].kbuf)
 			goto out_free;
-		if (tep_is_old_format(pevent))
+		if (tep_is_old_format(handle->pevent))
 			kbuffer_set_old_format(handle->cpu_data[cpu].kbuf);
 
-		read8(handle, &offset);
-		read8(handle, &size);
-
-		handle->cpu_data[cpu].file_offset = offset;
-		handle->cpu_data[cpu].file_size = size;
-		if (size > max_size)
-			max_size = size;
-
-		if (size && (offset + size > handle->total_file_size)) {
-			/* this happens if the file got truncated */
-			printf("File possibly truncated. "
-				"Need at least %llu, but file size is %zu.\n",
-				offset + size, handle->total_file_size);
-			errno = EINVAL;
-			goto out_free;
-		}
+		if (handle->cpu_data[cpu].file_size > max_size)
+			max_size = handle->cpu_data[cpu].file_size;
 	}
 
 	/* Calculate about a meg of pages for buffering */
@@ -3288,6 +3254,101 @@ static int read_cpu_data(struct tracecmd_input *handle)
 			goto out_free;
 	}
 
+	return 0;
+
+ out_free:
+	for ( ; cpu >= 0; cpu--) {
+		free_page(handle, cpu);
+		kbuffer_free(handle->cpu_data[cpu].kbuf);
+		handle->cpu_data[cpu].kbuf = NULL;
+	}
+	return -1;
+}
+
+static int init_buffer_cpu_data(struct tracecmd_input *handle, struct input_buffer_instance *buffer)
+{
+	unsigned long long offset;
+	unsigned long long size;
+	unsigned short id, flags;
+	int cpu;
+
+	if (handle->cpu_data)
+		return -1;
+
+	if (lseek64(handle->fd, buffer->offset, SEEK_SET) == (off_t)-1)
+		return -1;
+	if (read_section_header(handle, &id, &flags, NULL, NULL))
+		return -1;
+
+	handle->file_state = TRACECMD_FILE_CPU_FLYRECORD;
+	handle->cpus = buffer->cpus;
+	if (handle->max_cpu < handle->cpus)
+		handle->max_cpu = handle->cpus;
+
+	handle->cpu_data = calloc(handle->cpus, sizeof(*handle->cpu_data));
+	if (!handle->cpu_data)
+		return -1;
+
+	for (cpu = 0; cpu < handle->cpus; cpu++) {
+		handle->cpu_data[cpu].cpu = buffer->cpu_data[cpu].cpu;
+		offset = buffer->cpu_data[cpu].offset;
+		size = buffer->cpu_data[cpu].size;
+		handle->cpu_data[cpu].file_offset = offset;
+		handle->cpu_data[cpu].file_size = size;
+		if (size && (offset + size > handle->total_file_size)) {
+			/* this happens if the file got truncated */
+			printf("File possibly truncated. "
+				"Need at least %llu, but file size is %zu.\n",
+				offset + size, handle->total_file_size);
+			errno = EINVAL;
+			return -1;
+		}
+	}
+
+	return init_cpu_data(handle);
+}
+
+static int read_cpu_data(struct tracecmd_input *handle)
+{
+	unsigned long long size;
+	int cpus;
+	int cpu;
+
+	/*
+	 * Check if this is a latency report or not.
+	 */
+	if (handle->file_state == TRACECMD_FILE_CPU_LATENCY)
+		return 1;
+
+	/* We expect this to be flyrecord */
+	if (handle->file_state != TRACECMD_FILE_CPU_FLYRECORD)
+		return -1;
+
+	cpus = handle->cpus;
+
+	handle->cpu_data = malloc(sizeof(*handle->cpu_data) * handle->cpus);
+	if (!handle->cpu_data)
+		return -1;
+	memset(handle->cpu_data, 0, sizeof(*handle->cpu_data) * handle->cpus);
+
+	for (cpu = 0; cpu < handle->cpus; cpu++) {
+		unsigned long long offset;
+
+		handle->cpu_data[cpu].cpu = cpu;
+		read8(handle, &offset);
+		read8(handle, &size);
+		handle->cpu_data[cpu].file_offset = offset;
+		handle->cpu_data[cpu].file_size = size;
+		if (size && (offset + size > handle->total_file_size)) {
+			/* this happens if the file got truncated */
+			printf("File possibly truncated. "
+				"Need at least %llu, but file size is %zu.\n",
+				offset + size, handle->total_file_size);
+			errno = EINVAL;
+			return -1;
+		}
+	}
+
 	/*
 	 * It is possible that an option changed the number of CPUs.
 	 * If that happened, then there's "empty" cpu data saved for
@@ -3307,15 +3368,7 @@ static int read_cpu_data(struct tracecmd_input *handle)
 		}
 	}
 
-	return 0;
-
- out_free:
-	for ( ; cpu >= 0; cpu--) {
-		free_page(handle, cpu);
-		kbuffer_free(handle->cpu_data[cpu].kbuf);
-		handle->cpu_data[cpu].kbuf = NULL;
-	}
-	return -1;
+	return init_cpu_data(handle);
 }
 
 static int read_data_and_size(struct tracecmd_input *handle,
@@ -3418,14 +3471,7 @@ static int read_and_parse_trace_clock(struct tracecmd_input *handle,
 	return 0;
 }
 
-/**
- * tracecmd_init_data - prepare reading the data from trace.dat
- * @handle: input handle for the trace.dat file
- *
- * This prepares reading the data from trace.dat. This is called
- * after tracecmd_read_headers() and before tracecmd_read_data().
- */
-int tracecmd_init_data(struct tracecmd_input *handle)
+static int init_data_v6(struct tracecmd_input *handle)
 {
 	struct tep_handle *pevent = handle->pevent;
 	int ret;
@@ -3447,7 +3493,29 @@ int tracecmd_init_data(struct tracecmd_input *handle)
 			tracecmd_parse_trace_clock(handle, clock, 8);
 		}
 	}
+	return ret;
+}
+
+static int init_data_v7(struct tracecmd_input *handle)
+{
+	return init_buffer_cpu_data(handle, &handle->top_buffer);
+}
 
+/**
+ * tracecmd_init_data - prepare reading the data from trace.dat
+ * @handle: input handle for the trace.dat file
+ *
+ * This prepares reading the data from trace.dat. This is called
+ * after tracecmd_read_headers() and before tracecmd_read_data().
+ */
+int tracecmd_init_data(struct tracecmd_input *handle)
+{
+	int ret;
+
+	if (handle->file_version < 7)
+		ret = init_data_v6(handle);
+	else
+		ret = init_data_v7(handle);
 	tracecmd_blk_hack(handle);
 
 	return ret;
-- 
2.31.1