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Commit 7a6f205d authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

perf buildid-list: Support showing the build id in an ELF file 

Try first reading the build id, validating that it is an ELF file, etc.
Cheap as libelf will bail out as soon as the magic number check fails.

Useful when investigating debuginfo packaging problems like this one:

[root@emilia ~]# perf buildid-list -i /usr/lib/debug/lib/modules/`uname -r`/vmlinux
77bb4ea591a602d455ace759a377c9adfff1aba3
[root@emilia ~]# perf buildid-list -k
07b0c016a2b30004e86132d0239945b1e88f5d75
[root@emilia ~]#

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-4elot9oxwa0rr0d90dshca3a@git.kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent f2add9cd

tools/perf/Documentation/perf-buildid-list.txt

+2 −1
Original line number Diff line number Diff line
@@ -16,7 +16,8 @@ This command displays the buildids found in a perf.data file, so that other 
tools can be used to fetch packages with matching symbol tables for use by

perf report.



It can also be used to show the build id of the running kernel.

It can also be used to show the build id of the running kernel or in an ELF

file using -i/--input.



OPTIONS

-------

tools/perf/builtin-buildid-list.c

+24 −3
Original line number Diff line number Diff line 
/*

 * builtin-buildid-list.c

 *

 * Builtin buildid-list command: list buildids in perf.data or in the running

 * kernel.

 * Builtin buildid-list command: list buildids in perf.data, in the running

 * kernel and in ELF files.

 *

 * Copyright (C) 2009, Red Hat Inc.

 * Copyright (C) 2009, Arnaldo Carvalho de Melo <acme@redhat.com>
@@ -16,6 +16,8 @@ 
#include "util/session.h"

#include "util/symbol.h"



#include <libelf.h>



static char const *input_name = "perf.data";

static bool force;

static bool show_kernel;
@@ -70,12 +72,31 @@ static int sysfs__fprintf_build_id(FILE *fp) 
	return 0;

}



static int __cmd_buildid_list(void)

static int filename__fprintf_build_id(const char *name, FILE *fp)

{

	u8 build_id[BUILD_ID_SIZE];

	char sbuild_id[BUILD_ID_SIZE * 2 + 1];



	if (filename__read_build_id(name, build_id,

				    sizeof(build_id)) != sizeof(build_id))

		return 0;



	build_id__sprintf(build_id, sizeof(build_id), sbuild_id);

	return fprintf(fp, "%s\n", sbuild_id);

}



static int __cmd_buildid_list(void)

{

	if (show_kernel)

		return sysfs__fprintf_build_id(stdout);



	elf_version(EV_CURRENT);

	/*

 	 * See if this is an ELF file first:

 	 */

	if (filename__fprintf_build_id(input_name, stdout))

		return 0;



	return perf_session__list_build_ids();

}