linux/tools/perf/util/header.c
Arnaldo Carvalho de Melo ec80fde746 perf symbols: Handle /proc/sys/kernel/kptr_restrict
Perf uses /proc/modules to figure out where kernel modules are loaded.

With the advent of kptr_restrict, non root users get zeroes for all module
start addresses.

So check if kptr_restrict is non zero and don't generate the syntethic
PERF_RECORD_MMAP events for them.

Warn the user about it in perf record and in perf report.

In perf report the reference relocation symbol being zero means that
kptr_restrict was set, thus /proc/kallsyms has only zeroed addresses, so don't
use it to fixup symbol addresses when using a valid kallsyms (in the buildid
cache) or vmlinux (in the vmlinux path) build-id located automatically or
specified by the user.

Provide an explanation about it in 'perf report' if kernel samples were taken,
checking if a suitable vmlinux or kallsyms was found/specified.

Restricted /proc/kallsyms don't go to the buildid cache anymore.

Example:

 [acme@emilia ~]$ perf record -F 100000 sleep 1

 WARNING: Kernel address maps (/proc/{kallsyms,modules}) are restricted, check
 /proc/sys/kernel/kptr_restrict.

 Samples in kernel functions may not be resolved if a suitable vmlinux file is
 not found in the buildid cache or in the vmlinux path.

 Samples in kernel modules won't be resolved at all.

 If some relocation was applied (e.g. kexec) symbols may be misresolved even
 with a suitable vmlinux or kallsyms file.

 [ perf record: Woken up 1 times to write data ]
 [ perf record: Captured and wrote 0.005 MB perf.data (~231 samples) ]
 [acme@emilia ~]$

 [acme@emilia ~]$ perf report --stdio
 Kernel address maps (/proc/{kallsyms,modules}) were restricted,
 check /proc/sys/kernel/kptr_restrict before running 'perf record'.

 If some relocation was applied (e.g. kexec) symbols may be misresolved.

 Samples in kernel modules can't be resolved as well.

 # Events: 13  cycles
 #
 # Overhead  Command      Shared Object                 Symbol
 # ........  .......  .................  .....................
 #
    20.24%    sleep  [kernel.kallsyms]  [k] page_fault
    20.04%    sleep  [kernel.kallsyms]  [k] filemap_fault
    19.78%    sleep  [kernel.kallsyms]  [k] __lru_cache_add
    19.69%    sleep  ld-2.12.so         [.] memcpy
    14.71%    sleep  [kernel.kallsyms]  [k] dput
     4.70%    sleep  [kernel.kallsyms]  [k] flush_signal_handlers
     0.73%    sleep  [kernel.kallsyms]  [k] perf_event_comm
     0.11%    sleep  [kernel.kallsyms]  [k] native_write_msr_safe

 #
 # (For a higher level overview, try: perf report --sort comm,dso)
 #
 [acme@emilia ~]$

This is because it found a suitable vmlinux (build-id checked) in
/lib/modules/2.6.39-rc7+/build/vmlinux (use -v in perf report to see the long
file name).

If we remove that file from the vmlinux path:

 [root@emilia ~]# mv /lib/modules/2.6.39-rc7+/build/vmlinux \
		     /lib/modules/2.6.39-rc7+/build/vmlinux.OFF
 [acme@emilia ~]$ perf report --stdio
 [kernel.kallsyms] with build id 57298cdbe0131f6871667ec0eaab4804dcf6f562
 not found, continuing without symbols

 Kernel address maps (/proc/{kallsyms,modules}) were restricted, check
 /proc/sys/kernel/kptr_restrict before running 'perf record'.

 As no suitable kallsyms nor vmlinux was found, kernel samples can't be
 resolved.

 Samples in kernel modules can't be resolved as well.

 # Events: 13  cycles
 #
 # Overhead  Command      Shared Object  Symbol
 # ........  .......  .................  ......
 #
    80.31%    sleep  [kernel.kallsyms]  [k] 0xffffffff8103425a
    19.69%    sleep  ld-2.12.so         [.] memcpy

 #
 # (For a higher level overview, try: perf report --sort comm,dso)
 #
 [acme@emilia ~]$

Reported-by: Stephane Eranian <eranian@google.com>
Suggested-by: David Miller <davem@davemloft.net>
Cc: Dave Jones <davej@redhat.com>
Cc: David Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Kees Cook <kees.cook@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Link: http://lkml.kernel.org/n/tip-mt512joaxxbhhp1odop04yit@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2011-05-26 11:15:25 -03:00

1183 lines
28 KiB
C

#define _FILE_OFFSET_BITS 64
#include <sys/types.h>
#include <byteswap.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include "evlist.h"
#include "evsel.h"
#include "util.h"
#include "header.h"
#include "../perf.h"
#include "trace-event.h"
#include "session.h"
#include "symbol.h"
#include "debug.h"
static bool no_buildid_cache = false;
static int event_count;
static struct perf_trace_event_type *events;
int perf_header__push_event(u64 id, const char *name)
{
if (strlen(name) > MAX_EVENT_NAME)
pr_warning("Event %s will be truncated\n", name);
if (!events) {
events = malloc(sizeof(struct perf_trace_event_type));
if (events == NULL)
return -ENOMEM;
} else {
struct perf_trace_event_type *nevents;
nevents = realloc(events, (event_count + 1) * sizeof(*events));
if (nevents == NULL)
return -ENOMEM;
events = nevents;
}
memset(&events[event_count], 0, sizeof(struct perf_trace_event_type));
events[event_count].event_id = id;
strncpy(events[event_count].name, name, MAX_EVENT_NAME - 1);
event_count++;
return 0;
}
char *perf_header__find_event(u64 id)
{
int i;
for (i = 0 ; i < event_count; i++) {
if (events[i].event_id == id)
return events[i].name;
}
return NULL;
}
static const char *__perf_magic = "PERFFILE";
#define PERF_MAGIC (*(u64 *)__perf_magic)
struct perf_file_attr {
struct perf_event_attr attr;
struct perf_file_section ids;
};
void perf_header__set_feat(struct perf_header *header, int feat)
{
set_bit(feat, header->adds_features);
}
void perf_header__clear_feat(struct perf_header *header, int feat)
{
clear_bit(feat, header->adds_features);
}
bool perf_header__has_feat(const struct perf_header *header, int feat)
{
return test_bit(feat, header->adds_features);
}
static int do_write(int fd, const void *buf, size_t size)
{
while (size) {
int ret = write(fd, buf, size);
if (ret < 0)
return -errno;
size -= ret;
buf += ret;
}
return 0;
}
#define NAME_ALIGN 64
static int write_padded(int fd, const void *bf, size_t count,
size_t count_aligned)
{
static const char zero_buf[NAME_ALIGN];
int err = do_write(fd, bf, count);
if (!err)
err = do_write(fd, zero_buf, count_aligned - count);
return err;
}
#define dsos__for_each_with_build_id(pos, head) \
list_for_each_entry(pos, head, node) \
if (!pos->has_build_id) \
continue; \
else
static int __dsos__write_buildid_table(struct list_head *head, pid_t pid,
u16 misc, int fd)
{
struct dso *pos;
dsos__for_each_with_build_id(pos, head) {
int err;
struct build_id_event b;
size_t len;
if (!pos->hit)
continue;
len = pos->long_name_len + 1;
len = ALIGN(len, NAME_ALIGN);
memset(&b, 0, sizeof(b));
memcpy(&b.build_id, pos->build_id, sizeof(pos->build_id));
b.pid = pid;
b.header.misc = misc;
b.header.size = sizeof(b) + len;
err = do_write(fd, &b, sizeof(b));
if (err < 0)
return err;
err = write_padded(fd, pos->long_name,
pos->long_name_len + 1, len);
if (err < 0)
return err;
}
return 0;
}
static int machine__write_buildid_table(struct machine *machine, int fd)
{
int err;
u16 kmisc = PERF_RECORD_MISC_KERNEL,
umisc = PERF_RECORD_MISC_USER;
if (!machine__is_host(machine)) {
kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
umisc = PERF_RECORD_MISC_GUEST_USER;
}
err = __dsos__write_buildid_table(&machine->kernel_dsos, machine->pid,
kmisc, fd);
if (err == 0)
err = __dsos__write_buildid_table(&machine->user_dsos,
machine->pid, umisc, fd);
return err;
}
static int dsos__write_buildid_table(struct perf_header *header, int fd)
{
struct perf_session *session = container_of(header,
struct perf_session, header);
struct rb_node *nd;
int err = machine__write_buildid_table(&session->host_machine, fd);
if (err)
return err;
for (nd = rb_first(&session->machines); nd; nd = rb_next(nd)) {
struct machine *pos = rb_entry(nd, struct machine, rb_node);
err = machine__write_buildid_table(pos, fd);
if (err)
break;
}
return err;
}
int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
const char *name, bool is_kallsyms)
{
const size_t size = PATH_MAX;
char *realname, *filename = malloc(size),
*linkname = malloc(size), *targetname;
int len, err = -1;
if (is_kallsyms) {
if (symbol_conf.kptr_restrict) {
pr_debug("Not caching a kptr_restrict'ed /proc/kallsyms\n");
return 0;
}
realname = (char *)name;
} else
realname = realpath(name, NULL);
if (realname == NULL || filename == NULL || linkname == NULL)
goto out_free;
len = snprintf(filename, size, "%s%s%s",
debugdir, is_kallsyms ? "/" : "", realname);
if (mkdir_p(filename, 0755))
goto out_free;
snprintf(filename + len, sizeof(filename) - len, "/%s", sbuild_id);
if (access(filename, F_OK)) {
if (is_kallsyms) {
if (copyfile("/proc/kallsyms", filename))
goto out_free;
} else if (link(realname, filename) && copyfile(name, filename))
goto out_free;
}
len = snprintf(linkname, size, "%s/.build-id/%.2s",
debugdir, sbuild_id);
if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
goto out_free;
snprintf(linkname + len, size - len, "/%s", sbuild_id + 2);
targetname = filename + strlen(debugdir) - 5;
memcpy(targetname, "../..", 5);
if (symlink(targetname, linkname) == 0)
err = 0;
out_free:
if (!is_kallsyms)
free(realname);
free(filename);
free(linkname);
return err;
}
static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
const char *name, const char *debugdir,
bool is_kallsyms)
{
char sbuild_id[BUILD_ID_SIZE * 2 + 1];
build_id__sprintf(build_id, build_id_size, sbuild_id);
return build_id_cache__add_s(sbuild_id, debugdir, name, is_kallsyms);
}
int build_id_cache__remove_s(const char *sbuild_id, const char *debugdir)
{
const size_t size = PATH_MAX;
char *filename = malloc(size),
*linkname = malloc(size);
int err = -1;
if (filename == NULL || linkname == NULL)
goto out_free;
snprintf(linkname, size, "%s/.build-id/%.2s/%s",
debugdir, sbuild_id, sbuild_id + 2);
if (access(linkname, F_OK))
goto out_free;
if (readlink(linkname, filename, size) < 0)
goto out_free;
if (unlink(linkname))
goto out_free;
/*
* Since the link is relative, we must make it absolute:
*/
snprintf(linkname, size, "%s/.build-id/%.2s/%s",
debugdir, sbuild_id, filename);
if (unlink(linkname))
goto out_free;
err = 0;
out_free:
free(filename);
free(linkname);
return err;
}
static int dso__cache_build_id(struct dso *dso, const char *debugdir)
{
bool is_kallsyms = dso->kernel && dso->long_name[0] != '/';
return build_id_cache__add_b(dso->build_id, sizeof(dso->build_id),
dso->long_name, debugdir, is_kallsyms);
}
static int __dsos__cache_build_ids(struct list_head *head, const char *debugdir)
{
struct dso *pos;
int err = 0;
dsos__for_each_with_build_id(pos, head)
if (dso__cache_build_id(pos, debugdir))
err = -1;
return err;
}
static int machine__cache_build_ids(struct machine *machine, const char *debugdir)
{
int ret = __dsos__cache_build_ids(&machine->kernel_dsos, debugdir);
ret |= __dsos__cache_build_ids(&machine->user_dsos, debugdir);
return ret;
}
static int perf_session__cache_build_ids(struct perf_session *session)
{
struct rb_node *nd;
int ret;
char debugdir[PATH_MAX];
snprintf(debugdir, sizeof(debugdir), "%s", buildid_dir);
if (mkdir(debugdir, 0755) != 0 && errno != EEXIST)
return -1;
ret = machine__cache_build_ids(&session->host_machine, debugdir);
for (nd = rb_first(&session->machines); nd; nd = rb_next(nd)) {
struct machine *pos = rb_entry(nd, struct machine, rb_node);
ret |= machine__cache_build_ids(pos, debugdir);
}
return ret ? -1 : 0;
}
static bool machine__read_build_ids(struct machine *machine, bool with_hits)
{
bool ret = __dsos__read_build_ids(&machine->kernel_dsos, with_hits);
ret |= __dsos__read_build_ids(&machine->user_dsos, with_hits);
return ret;
}
static bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
{
struct rb_node *nd;
bool ret = machine__read_build_ids(&session->host_machine, with_hits);
for (nd = rb_first(&session->machines); nd; nd = rb_next(nd)) {
struct machine *pos = rb_entry(nd, struct machine, rb_node);
ret |= machine__read_build_ids(pos, with_hits);
}
return ret;
}
static int perf_header__adds_write(struct perf_header *header,
struct perf_evlist *evlist, int fd)
{
int nr_sections;
struct perf_session *session;
struct perf_file_section *feat_sec;
int sec_size;
u64 sec_start;
int idx = 0, err;
session = container_of(header, struct perf_session, header);
if (perf_header__has_feat(header, HEADER_BUILD_ID &&
!perf_session__read_build_ids(session, true)))
perf_header__clear_feat(header, HEADER_BUILD_ID);
nr_sections = bitmap_weight(header->adds_features, HEADER_FEAT_BITS);
if (!nr_sections)
return 0;
feat_sec = calloc(sizeof(*feat_sec), nr_sections);
if (feat_sec == NULL)
return -ENOMEM;
sec_size = sizeof(*feat_sec) * nr_sections;
sec_start = header->data_offset + header->data_size;
lseek(fd, sec_start + sec_size, SEEK_SET);
if (perf_header__has_feat(header, HEADER_TRACE_INFO)) {
struct perf_file_section *trace_sec;
trace_sec = &feat_sec[idx++];
/* Write trace info */
trace_sec->offset = lseek(fd, 0, SEEK_CUR);
read_tracing_data(fd, &evlist->entries);
trace_sec->size = lseek(fd, 0, SEEK_CUR) - trace_sec->offset;
}
if (perf_header__has_feat(header, HEADER_BUILD_ID)) {
struct perf_file_section *buildid_sec;
buildid_sec = &feat_sec[idx++];
/* Write build-ids */
buildid_sec->offset = lseek(fd, 0, SEEK_CUR);
err = dsos__write_buildid_table(header, fd);
if (err < 0) {
pr_debug("failed to write buildid table\n");
goto out_free;
}
buildid_sec->size = lseek(fd, 0, SEEK_CUR) -
buildid_sec->offset;
if (!no_buildid_cache)
perf_session__cache_build_ids(session);
}
lseek(fd, sec_start, SEEK_SET);
err = do_write(fd, feat_sec, sec_size);
if (err < 0)
pr_debug("failed to write feature section\n");
out_free:
free(feat_sec);
return err;
}
int perf_header__write_pipe(int fd)
{
struct perf_pipe_file_header f_header;
int err;
f_header = (struct perf_pipe_file_header){
.magic = PERF_MAGIC,
.size = sizeof(f_header),
};
err = do_write(fd, &f_header, sizeof(f_header));
if (err < 0) {
pr_debug("failed to write perf pipe header\n");
return err;
}
return 0;
}
int perf_session__write_header(struct perf_session *session,
struct perf_evlist *evlist,
int fd, bool at_exit)
{
struct perf_file_header f_header;
struct perf_file_attr f_attr;
struct perf_header *header = &session->header;
struct perf_evsel *attr, *pair = NULL;
int err;
lseek(fd, sizeof(f_header), SEEK_SET);
if (session->evlist != evlist)
pair = list_entry(session->evlist->entries.next, struct perf_evsel, node);
list_for_each_entry(attr, &evlist->entries, node) {
attr->id_offset = lseek(fd, 0, SEEK_CUR);
err = do_write(fd, attr->id, attr->ids * sizeof(u64));
if (err < 0) {
out_err_write:
pr_debug("failed to write perf header\n");
return err;
}
if (session->evlist != evlist) {
err = do_write(fd, pair->id, pair->ids * sizeof(u64));
if (err < 0)
goto out_err_write;
attr->ids += pair->ids;
pair = list_entry(pair->node.next, struct perf_evsel, node);
}
}
header->attr_offset = lseek(fd, 0, SEEK_CUR);
list_for_each_entry(attr, &evlist->entries, node) {
f_attr = (struct perf_file_attr){
.attr = attr->attr,
.ids = {
.offset = attr->id_offset,
.size = attr->ids * sizeof(u64),
}
};
err = do_write(fd, &f_attr, sizeof(f_attr));
if (err < 0) {
pr_debug("failed to write perf header attribute\n");
return err;
}
}
header->event_offset = lseek(fd, 0, SEEK_CUR);
header->event_size = event_count * sizeof(struct perf_trace_event_type);
if (events) {
err = do_write(fd, events, header->event_size);
if (err < 0) {
pr_debug("failed to write perf header events\n");
return err;
}
}
header->data_offset = lseek(fd, 0, SEEK_CUR);
if (at_exit) {
err = perf_header__adds_write(header, evlist, fd);
if (err < 0)
return err;
}
f_header = (struct perf_file_header){
.magic = PERF_MAGIC,
.size = sizeof(f_header),
.attr_size = sizeof(f_attr),
.attrs = {
.offset = header->attr_offset,
.size = evlist->nr_entries * sizeof(f_attr),
},
.data = {
.offset = header->data_offset,
.size = header->data_size,
},
.event_types = {
.offset = header->event_offset,
.size = header->event_size,
},
};
memcpy(&f_header.adds_features, &header->adds_features, sizeof(header->adds_features));
lseek(fd, 0, SEEK_SET);
err = do_write(fd, &f_header, sizeof(f_header));
if (err < 0) {
pr_debug("failed to write perf header\n");
return err;
}
lseek(fd, header->data_offset + header->data_size, SEEK_SET);
header->frozen = 1;
return 0;
}
static int perf_header__getbuffer64(struct perf_header *header,
int fd, void *buf, size_t size)
{
if (readn(fd, buf, size) <= 0)
return -1;
if (header->needs_swap)
mem_bswap_64(buf, size);
return 0;
}
int perf_header__process_sections(struct perf_header *header, int fd,
int (*process)(struct perf_file_section *section,
struct perf_header *ph,
int feat, int fd))
{
struct perf_file_section *feat_sec;
int nr_sections;
int sec_size;
int idx = 0;
int err = -1, feat = 1;
nr_sections = bitmap_weight(header->adds_features, HEADER_FEAT_BITS);
if (!nr_sections)
return 0;
feat_sec = calloc(sizeof(*feat_sec), nr_sections);
if (!feat_sec)
return -1;
sec_size = sizeof(*feat_sec) * nr_sections;
lseek(fd, header->data_offset + header->data_size, SEEK_SET);
if (perf_header__getbuffer64(header, fd, feat_sec, sec_size))
goto out_free;
err = 0;
while (idx < nr_sections && feat < HEADER_LAST_FEATURE) {
if (perf_header__has_feat(header, feat)) {
struct perf_file_section *sec = &feat_sec[idx++];
err = process(sec, header, feat, fd);
if (err < 0)
break;
}
++feat;
}
out_free:
free(feat_sec);
return err;
}
int perf_file_header__read(struct perf_file_header *header,
struct perf_header *ph, int fd)
{
lseek(fd, 0, SEEK_SET);
if (readn(fd, header, sizeof(*header)) <= 0 ||
memcmp(&header->magic, __perf_magic, sizeof(header->magic)))
return -1;
if (header->attr_size != sizeof(struct perf_file_attr)) {
u64 attr_size = bswap_64(header->attr_size);
if (attr_size != sizeof(struct perf_file_attr))
return -1;
mem_bswap_64(header, offsetof(struct perf_file_header,
adds_features));
ph->needs_swap = true;
}
if (header->size != sizeof(*header)) {
/* Support the previous format */
if (header->size == offsetof(typeof(*header), adds_features))
bitmap_zero(header->adds_features, HEADER_FEAT_BITS);
else
return -1;
}
memcpy(&ph->adds_features, &header->adds_features,
sizeof(ph->adds_features));
/*
* FIXME: hack that assumes that if we need swap the perf.data file
* may be coming from an arch with a different word-size, ergo different
* DEFINE_BITMAP format, investigate more later, but for now its mostly
* safe to assume that we have a build-id section. Trace files probably
* have several other issues in this realm anyway...
*/
if (ph->needs_swap) {
memset(&ph->adds_features, 0, sizeof(ph->adds_features));
perf_header__set_feat(ph, HEADER_BUILD_ID);
}
ph->event_offset = header->event_types.offset;
ph->event_size = header->event_types.size;
ph->data_offset = header->data.offset;
ph->data_size = header->data.size;
return 0;
}
static int __event_process_build_id(struct build_id_event *bev,
char *filename,
struct perf_session *session)
{
int err = -1;
struct list_head *head;
struct machine *machine;
u16 misc;
struct dso *dso;
enum dso_kernel_type dso_type;
machine = perf_session__findnew_machine(session, bev->pid);
if (!machine)
goto out;
misc = bev->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
switch (misc) {
case PERF_RECORD_MISC_KERNEL:
dso_type = DSO_TYPE_KERNEL;
head = &machine->kernel_dsos;
break;
case PERF_RECORD_MISC_GUEST_KERNEL:
dso_type = DSO_TYPE_GUEST_KERNEL;
head = &machine->kernel_dsos;
break;
case PERF_RECORD_MISC_USER:
case PERF_RECORD_MISC_GUEST_USER:
dso_type = DSO_TYPE_USER;
head = &machine->user_dsos;
break;
default:
goto out;
}
dso = __dsos__findnew(head, filename);
if (dso != NULL) {
char sbuild_id[BUILD_ID_SIZE * 2 + 1];
dso__set_build_id(dso, &bev->build_id);
if (filename[0] == '[')
dso->kernel = dso_type;
build_id__sprintf(dso->build_id, sizeof(dso->build_id),
sbuild_id);
pr_debug("build id event received for %s: %s\n",
dso->long_name, sbuild_id);
}
err = 0;
out:
return err;
}
static int perf_header__read_build_ids_abi_quirk(struct perf_header *header,
int input, u64 offset, u64 size)
{
struct perf_session *session = container_of(header, struct perf_session, header);
struct {
struct perf_event_header header;
u8 build_id[ALIGN(BUILD_ID_SIZE, sizeof(u64))];
char filename[0];
} old_bev;
struct build_id_event bev;
char filename[PATH_MAX];
u64 limit = offset + size;
while (offset < limit) {
ssize_t len;
if (read(input, &old_bev, sizeof(old_bev)) != sizeof(old_bev))
return -1;
if (header->needs_swap)
perf_event_header__bswap(&old_bev.header);
len = old_bev.header.size - sizeof(old_bev);
if (read(input, filename, len) != len)
return -1;
bev.header = old_bev.header;
bev.pid = 0;
memcpy(bev.build_id, old_bev.build_id, sizeof(bev.build_id));
__event_process_build_id(&bev, filename, session);
offset += bev.header.size;
}
return 0;
}
static int perf_header__read_build_ids(struct perf_header *header,
int input, u64 offset, u64 size)
{
struct perf_session *session = container_of(header, struct perf_session, header);
struct build_id_event bev;
char filename[PATH_MAX];
u64 limit = offset + size, orig_offset = offset;
int err = -1;
while (offset < limit) {
ssize_t len;
if (read(input, &bev, sizeof(bev)) != sizeof(bev))
goto out;
if (header->needs_swap)
perf_event_header__bswap(&bev.header);
len = bev.header.size - sizeof(bev);
if (read(input, filename, len) != len)
goto out;
/*
* The a1645ce1 changeset:
*
* "perf: 'perf kvm' tool for monitoring guest performance from host"
*
* Added a field to struct build_id_event that broke the file
* format.
*
* Since the kernel build-id is the first entry, process the
* table using the old format if the well known
* '[kernel.kallsyms]' string for the kernel build-id has the
* first 4 characters chopped off (where the pid_t sits).
*/
if (memcmp(filename, "nel.kallsyms]", 13) == 0) {
if (lseek(input, orig_offset, SEEK_SET) == (off_t)-1)
return -1;
return perf_header__read_build_ids_abi_quirk(header, input, offset, size);
}
__event_process_build_id(&bev, filename, session);
offset += bev.header.size;
}
err = 0;
out:
return err;
}
static int perf_file_section__process(struct perf_file_section *section,
struct perf_header *ph,
int feat, int fd)
{
if (lseek(fd, section->offset, SEEK_SET) == (off_t)-1) {
pr_debug("Failed to lseek to %" PRIu64 " offset for feature "
"%d, continuing...\n", section->offset, feat);
return 0;
}
switch (feat) {
case HEADER_TRACE_INFO:
trace_report(fd, false);
break;
case HEADER_BUILD_ID:
if (perf_header__read_build_ids(ph, fd, section->offset, section->size))
pr_debug("Failed to read buildids, continuing...\n");
break;
default:
pr_debug("unknown feature %d, continuing...\n", feat);
}
return 0;
}
static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
struct perf_header *ph, int fd,
bool repipe)
{
if (readn(fd, header, sizeof(*header)) <= 0 ||
memcmp(&header->magic, __perf_magic, sizeof(header->magic)))
return -1;
if (repipe && do_write(STDOUT_FILENO, header, sizeof(*header)) < 0)
return -1;
if (header->size != sizeof(*header)) {
u64 size = bswap_64(header->size);
if (size != sizeof(*header))
return -1;
ph->needs_swap = true;
}
return 0;
}
static int perf_header__read_pipe(struct perf_session *session, int fd)
{
struct perf_header *header = &session->header;
struct perf_pipe_file_header f_header;
if (perf_file_header__read_pipe(&f_header, header, fd,
session->repipe) < 0) {
pr_debug("incompatible file format\n");
return -EINVAL;
}
session->fd = fd;
return 0;
}
int perf_session__read_header(struct perf_session *session, int fd)
{
struct perf_header *header = &session->header;
struct perf_file_header f_header;
struct perf_file_attr f_attr;
u64 f_id;
int nr_attrs, nr_ids, i, j;
session->evlist = perf_evlist__new(NULL, NULL);
if (session->evlist == NULL)
return -ENOMEM;
if (session->fd_pipe)
return perf_header__read_pipe(session, fd);
if (perf_file_header__read(&f_header, header, fd) < 0) {
pr_debug("incompatible file format\n");
return -EINVAL;
}
nr_attrs = f_header.attrs.size / sizeof(f_attr);
lseek(fd, f_header.attrs.offset, SEEK_SET);
for (i = 0; i < nr_attrs; i++) {
struct perf_evsel *evsel;
off_t tmp;
if (perf_header__getbuffer64(header, fd, &f_attr, sizeof(f_attr)))
goto out_errno;
tmp = lseek(fd, 0, SEEK_CUR);
evsel = perf_evsel__new(&f_attr.attr, i);
if (evsel == NULL)
goto out_delete_evlist;
/*
* Do it before so that if perf_evsel__alloc_id fails, this
* entry gets purged too at perf_evlist__delete().
*/
perf_evlist__add(session->evlist, evsel);
nr_ids = f_attr.ids.size / sizeof(u64);
/*
* We don't have the cpu and thread maps on the header, so
* for allocating the perf_sample_id table we fake 1 cpu and
* hattr->ids threads.
*/
if (perf_evsel__alloc_id(evsel, 1, nr_ids))
goto out_delete_evlist;
lseek(fd, f_attr.ids.offset, SEEK_SET);
for (j = 0; j < nr_ids; j++) {
if (perf_header__getbuffer64(header, fd, &f_id, sizeof(f_id)))
goto out_errno;
perf_evlist__id_add(session->evlist, evsel, 0, j, f_id);
}
lseek(fd, tmp, SEEK_SET);
}
if (f_header.event_types.size) {
lseek(fd, f_header.event_types.offset, SEEK_SET);
events = malloc(f_header.event_types.size);
if (events == NULL)
return -ENOMEM;
if (perf_header__getbuffer64(header, fd, events,
f_header.event_types.size))
goto out_errno;
event_count = f_header.event_types.size / sizeof(struct perf_trace_event_type);
}
perf_header__process_sections(header, fd, perf_file_section__process);
lseek(fd, header->data_offset, SEEK_SET);
header->frozen = 1;
return 0;
out_errno:
return -errno;
out_delete_evlist:
perf_evlist__delete(session->evlist);
session->evlist = NULL;
return -ENOMEM;
}
int perf_event__synthesize_attr(struct perf_event_attr *attr, u16 ids, u64 *id,
perf_event__handler_t process,
struct perf_session *session)
{
union perf_event *ev;
size_t size;
int err;
size = sizeof(struct perf_event_attr);
size = ALIGN(size, sizeof(u64));
size += sizeof(struct perf_event_header);
size += ids * sizeof(u64);
ev = malloc(size);
if (ev == NULL)
return -ENOMEM;
ev->attr.attr = *attr;
memcpy(ev->attr.id, id, ids * sizeof(u64));
ev->attr.header.type = PERF_RECORD_HEADER_ATTR;
ev->attr.header.size = size;
err = process(ev, NULL, session);
free(ev);
return err;
}
int perf_session__synthesize_attrs(struct perf_session *session,
perf_event__handler_t process)
{
struct perf_evsel *attr;
int err = 0;
list_for_each_entry(attr, &session->evlist->entries, node) {
err = perf_event__synthesize_attr(&attr->attr, attr->ids,
attr->id, process, session);
if (err) {
pr_debug("failed to create perf header attribute\n");
return err;
}
}
return err;
}
int perf_event__process_attr(union perf_event *event,
struct perf_session *session)
{
unsigned int i, ids, n_ids;
struct perf_evsel *evsel;
if (session->evlist == NULL) {
session->evlist = perf_evlist__new(NULL, NULL);
if (session->evlist == NULL)
return -ENOMEM;
}
evsel = perf_evsel__new(&event->attr.attr,
session->evlist->nr_entries);
if (evsel == NULL)
return -ENOMEM;
perf_evlist__add(session->evlist, evsel);
ids = event->header.size;
ids -= (void *)&event->attr.id - (void *)event;
n_ids = ids / sizeof(u64);
/*
* We don't have the cpu and thread maps on the header, so
* for allocating the perf_sample_id table we fake 1 cpu and
* hattr->ids threads.
*/
if (perf_evsel__alloc_id(evsel, 1, n_ids))
return -ENOMEM;
for (i = 0; i < n_ids; i++) {
perf_evlist__id_add(session->evlist, evsel, 0, i,
event->attr.id[i]);
}
perf_session__update_sample_type(session);
return 0;
}
int perf_event__synthesize_event_type(u64 event_id, char *name,
perf_event__handler_t process,
struct perf_session *session)
{
union perf_event ev;
size_t size = 0;
int err = 0;
memset(&ev, 0, sizeof(ev));
ev.event_type.event_type.event_id = event_id;
memset(ev.event_type.event_type.name, 0, MAX_EVENT_NAME);
strncpy(ev.event_type.event_type.name, name, MAX_EVENT_NAME - 1);
ev.event_type.header.type = PERF_RECORD_HEADER_EVENT_TYPE;
size = strlen(name);
size = ALIGN(size, sizeof(u64));
ev.event_type.header.size = sizeof(ev.event_type) -
(sizeof(ev.event_type.event_type.name) - size);
err = process(&ev, NULL, session);
return err;
}
int perf_event__synthesize_event_types(perf_event__handler_t process,
struct perf_session *session)
{
struct perf_trace_event_type *type;
int i, err = 0;
for (i = 0; i < event_count; i++) {
type = &events[i];
err = perf_event__synthesize_event_type(type->event_id,
type->name, process,
session);
if (err) {
pr_debug("failed to create perf header event type\n");
return err;
}
}
return err;
}
int perf_event__process_event_type(union perf_event *event,
struct perf_session *session __unused)
{
if (perf_header__push_event(event->event_type.event_type.event_id,
event->event_type.event_type.name) < 0)
return -ENOMEM;
return 0;
}
int perf_event__synthesize_tracing_data(int fd, struct perf_evlist *evlist,
perf_event__handler_t process,
struct perf_session *session __unused)
{
union perf_event ev;
ssize_t size = 0, aligned_size = 0, padding;
int err __used = 0;
memset(&ev, 0, sizeof(ev));
ev.tracing_data.header.type = PERF_RECORD_HEADER_TRACING_DATA;
size = read_tracing_data_size(fd, &evlist->entries);
if (size <= 0)
return size;
aligned_size = ALIGN(size, sizeof(u64));
padding = aligned_size - size;
ev.tracing_data.header.size = sizeof(ev.tracing_data);
ev.tracing_data.size = aligned_size;
process(&ev, NULL, session);
err = read_tracing_data(fd, &evlist->entries);
write_padded(fd, NULL, 0, padding);
return aligned_size;
}
int perf_event__process_tracing_data(union perf_event *event,
struct perf_session *session)
{
ssize_t size_read, padding, size = event->tracing_data.size;
off_t offset = lseek(session->fd, 0, SEEK_CUR);
char buf[BUFSIZ];
/* setup for reading amidst mmap */
lseek(session->fd, offset + sizeof(struct tracing_data_event),
SEEK_SET);
size_read = trace_report(session->fd, session->repipe);
padding = ALIGN(size_read, sizeof(u64)) - size_read;
if (read(session->fd, buf, padding) < 0)
die("reading input file");
if (session->repipe) {
int retw = write(STDOUT_FILENO, buf, padding);
if (retw <= 0 || retw != padding)
die("repiping tracing data padding");
}
if (size_read + padding != size)
die("tracing data size mismatch");
return size_read + padding;
}
int perf_event__synthesize_build_id(struct dso *pos, u16 misc,
perf_event__handler_t process,
struct machine *machine,
struct perf_session *session)
{
union perf_event ev;
size_t len;
int err = 0;
if (!pos->hit)
return err;
memset(&ev, 0, sizeof(ev));
len = pos->long_name_len + 1;
len = ALIGN(len, NAME_ALIGN);
memcpy(&ev.build_id.build_id, pos->build_id, sizeof(pos->build_id));
ev.build_id.header.type = PERF_RECORD_HEADER_BUILD_ID;
ev.build_id.header.misc = misc;
ev.build_id.pid = machine->pid;
ev.build_id.header.size = sizeof(ev.build_id) + len;
memcpy(&ev.build_id.filename, pos->long_name, pos->long_name_len);
err = process(&ev, NULL, session);
return err;
}
int perf_event__process_build_id(union perf_event *event,
struct perf_session *session)
{
__event_process_build_id(&event->build_id,
event->build_id.filename,
session);
return 0;
}
void disable_buildid_cache(void)
{
no_buildid_cache = true;
}