Moved, renamed, and deleted files

The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.

1 files changed, 2452 insertions, 0 deletions

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
new file mode 100644
index 00000000..c0b70c69
--- /dev/null
+++ b/tools/perf/util/header.c
@@ -0,0 +1,2452 @@
+#define _FILE_OFFSET_BITS 64
+
+#include "util.h"
+#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 <linux/bitops.h>
+#include <sys/utsname.h>
+
+#include "evlist.h"
+#include "evsel.h"
+#include "header.h"
+#include "../perf.h"
+#include "trace-event.h"
+#include "session.h"
+#include "symbol.h"
+#include "debug.h"
+#include "cpumap.h"
+
+static bool no_buildid_cache = false;
+
+static int event_count;
+static struct perf_trace_event_type *events;
+
+static u32 header_argc;
+static const char **header_argv;
+
+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;
+}
+
+/*
+ * magic2 = "PERFILE2"
+ * must be a numerical value to let the endianness
+ * determine the memory layout. That way we are able
+ * to detect endianness when reading the perf.data file
+ * back.
+ *
+ * we check for legacy (PERFFILE) format.
+ */
+static const char *__perf_magic1 = "PERFFILE";
+static const u64 __perf_magic2    = 0x32454c4946524550ULL;
+static const u64 __perf_magic2_sw = 0x50455246494c4532ULL;
+
+#define PERF_MAGIC	__perf_magic2
+
+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;
+}
+
+static int do_write_string(int fd, const char *str)
+{
+	u32 len, olen;
+	int ret;
+
+	olen = strlen(str) + 1;
+	len = ALIGN(olen, NAME_ALIGN);
+
+	/* write len, incl. \0 */
+	ret = do_write(fd, &len, sizeof(len));
+	if (ret < 0)
+		return ret;
+
+	return write_padded(fd, str, olen, len);
+}
+
+static char *do_read_string(int fd, struct perf_header *ph)
+{
+	ssize_t sz, ret;
+	u32 len;
+	char *buf;
+
+	sz = read(fd, &len, sizeof(len));
+	if (sz < (ssize_t)sizeof(len))
+		return NULL;
+
+	if (ph->needs_swap)
+		len = bswap_32(len);
+
+	buf = malloc(len);
+	if (!buf)
+		return NULL;
+
+	ret = read(fd, buf, len);
+	if (ret == (ssize_t)len) {
+		/*
+		 * strings are padded by zeroes
+		 * thus the actual strlen of buf
+		 * may be less than len
+		 */
+		return buf;
+	}
+
+	free(buf);
+	return NULL;
+}
+
+int
+perf_header__set_cmdline(int argc, const char **argv)
+{
+	int i;
+
+	header_argc = (u32)argc;
+
+	/* do not include NULL termination */
+	header_argv = calloc(argc, sizeof(char *));
+	if (!header_argv)
+		return -ENOMEM;
+
+	/*
+	 * must copy argv contents because it gets moved
+	 * around during option parsing
+	 */
+	for (i = 0; i < argc ; i++)
+		header_argv[i] = argv[i];
+
+	return 0;
+}
+
+#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 = zalloc(size),
+	     *linkname = zalloc(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 = scnprintf(filename, size, "%s%s%s",
+		       debugdir, is_kallsyms ? "/" : "", realname);
+	if (mkdir_p(filename, 0755))
+		goto out_free;
+
+	snprintf(filename + len, size - 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 = scnprintf(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 = zalloc(size),
+	     *linkname = zalloc(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 - 1) < 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 write_trace_info(int fd, struct perf_header *h __used,
+			    struct perf_evlist *evlist)
+{
+	return read_tracing_data(fd, &evlist->entries);
+}
+
+
+static int write_build_id(int fd, struct perf_header *h,
+			  struct perf_evlist *evlist __used)
+{
+	struct perf_session *session;
+	int err;
+
+	session = container_of(h, struct perf_session, header);
+
+	if (!perf_session__read_build_ids(session, true))
+		return -1;
+
+	err = dsos__write_buildid_table(h, fd);
+	if (err < 0) {
+		pr_debug("failed to write buildid table\n");
+		return err;
+	}
+	if (!no_buildid_cache)
+		perf_session__cache_build_ids(session);
+
+	return 0;
+}
+
+static int write_hostname(int fd, struct perf_header *h __used,
+			  struct perf_evlist *evlist __used)
+{
+	struct utsname uts;
+	int ret;
+
+	ret = uname(&uts);
+	if (ret < 0)
+		return -1;
+
+	return do_write_string(fd, uts.nodename);
+}
+
+static int write_osrelease(int fd, struct perf_header *h __used,
+			   struct perf_evlist *evlist __used)
+{
+	struct utsname uts;
+	int ret;
+
+	ret = uname(&uts);
+	if (ret < 0)
+		return -1;
+
+	return do_write_string(fd, uts.release);
+}
+
+static int write_arch(int fd, struct perf_header *h __used,
+		      struct perf_evlist *evlist __used)
+{
+	struct utsname uts;
+	int ret;
+
+	ret = uname(&uts);
+	if (ret < 0)
+		return -1;
+
+	return do_write_string(fd, uts.machine);
+}
+
+static int write_version(int fd, struct perf_header *h __used,
+			 struct perf_evlist *evlist __used)
+{
+	return do_write_string(fd, perf_version_string);
+}
+
+static int write_cpudesc(int fd, struct perf_header *h __used,
+		       struct perf_evlist *evlist __used)
+{
+#ifndef CPUINFO_PROC
+#define CPUINFO_PROC NULL
+#endif
+	FILE *file;
+	char *buf = NULL;
+	char *s, *p;
+	const char *search = CPUINFO_PROC;
+	size_t len = 0;
+	int ret = -1;
+
+	if (!search)
+		return -1;
+
+	file = fopen("/proc/cpuinfo", "r");
+	if (!file)
+		return -1;
+
+	while (getline(&buf, &len, file) > 0) {
+		ret = strncmp(buf, search, strlen(search));
+		if (!ret)
+			break;
+	}
+
+	if (ret)
+		goto done;
+
+	s = buf;
+
+	p = strchr(buf, ':');
+	if (p && *(p+1) == ' ' && *(p+2))
+		s = p + 2;
+	p = strchr(s, '\n');
+	if (p)
+		*p = '\0';
+
+	/* squash extra space characters (branding string) */
+	p = s;
+	while (*p) {
+		if (isspace(*p)) {
+			char *r = p + 1;
+			char *q = r;
+			*p = ' ';
+			while (*q && isspace(*q))
+				q++;
+			if (q != (p+1))
+				while ((*r++ = *q++));
+		}
+		p++;
+	}
+	ret = do_write_string(fd, s);
+done:
+	free(buf);
+	fclose(file);
+	return ret;
+}
+
+static int write_nrcpus(int fd, struct perf_header *h __used,
+			struct perf_evlist *evlist __used)
+{
+	long nr;
+	u32 nrc, nra;
+	int ret;
+
+	nr = sysconf(_SC_NPROCESSORS_CONF);
+	if (nr < 0)
+		return -1;
+
+	nrc = (u32)(nr & UINT_MAX);
+
+	nr = sysconf(_SC_NPROCESSORS_ONLN);
+	if (nr < 0)
+		return -1;
+
+	nra = (u32)(nr & UINT_MAX);
+
+	ret = do_write(fd, &nrc, sizeof(nrc));
+	if (ret < 0)
+		return ret;
+
+	return do_write(fd, &nra, sizeof(nra));
+}
+
+static int write_event_desc(int fd, struct perf_header *h __used,
+			    struct perf_evlist *evlist)
+{
+	struct perf_evsel *attr;
+	u32 nre = 0, nri, sz;
+	int ret;
+
+	list_for_each_entry(attr, &evlist->entries, node)
+		nre++;
+
+	/*
+	 * write number of events
+	 */
+	ret = do_write(fd, &nre, sizeof(nre));
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * size of perf_event_attr struct
+	 */
+	sz = (u32)sizeof(attr->attr);
+	ret = do_write(fd, &sz, sizeof(sz));
+	if (ret < 0)
+		return ret;
+
+	list_for_each_entry(attr, &evlist->entries, node) {
+
+		ret = do_write(fd, &attr->attr, sz);
+		if (ret < 0)
+			return ret;
+		/*
+		 * write number of unique id per event
+		 * there is one id per instance of an event
+		 *
+		 * copy into an nri to be independent of the
+		 * type of ids,
+		 */
+		nri = attr->ids;
+		ret = do_write(fd, &nri, sizeof(nri));
+		if (ret < 0)
+			return ret;
+
+		/*
+		 * write event string as passed on cmdline
+		 */
+		ret = do_write_string(fd, event_name(attr));
+		if (ret < 0)
+			return ret;
+		/*
+		 * write unique ids for this event
+		 */
+		ret = do_write(fd, attr->id, attr->ids * sizeof(u64));
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+static int write_cmdline(int fd, struct perf_header *h __used,
+			 struct perf_evlist *evlist __used)
+{
+	char buf[MAXPATHLEN];
+	char proc[32];
+	u32 i, n;
+	int ret;
+
+	/*
+	 * actual atual path to perf binary
+	 */
+	sprintf(proc, "/proc/%d/exe", getpid());
+	ret = readlink(proc, buf, sizeof(buf));
+	if (ret <= 0)
+		return -1;
+
+	/* readlink() does not add null termination */
+	buf[ret] = '\0';
+
+	/* account for binary path */
+	n = header_argc + 1;
+
+	ret = do_write(fd, &n, sizeof(n));
+	if (ret < 0)
+		return ret;
+
+	ret = do_write_string(fd, buf);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0 ; i < header_argc; i++) {
+		ret = do_write_string(fd, header_argv[i]);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+#define CORE_SIB_FMT \
+	"/sys/devices/system/cpu/cpu%d/topology/core_siblings_list"
+#define THRD_SIB_FMT \
+	"/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list"
+
+struct cpu_topo {
+	u32 core_sib;
+	u32 thread_sib;
+	char **core_siblings;
+	char **thread_siblings;
+};
+
+static int build_cpu_topo(struct cpu_topo *tp, int cpu)
+{
+	FILE *fp;
+	char filename[MAXPATHLEN];
+	char *buf = NULL, *p;
+	size_t len = 0;
+	u32 i = 0;
+	int ret = -1;
+
+	sprintf(filename, CORE_SIB_FMT, cpu);
+	fp = fopen(filename, "r");
+	if (!fp)
+		return -1;
+
+	if (getline(&buf, &len, fp) <= 0)
+		goto done;
+
+	fclose(fp);
+
+	p = strchr(buf, '\n');
+	if (p)
+		*p = '\0';
+
+	for (i = 0; i < tp->core_sib; i++) {
+		if (!strcmp(buf, tp->core_siblings[i]))
+			break;
+	}
+	if (i == tp->core_sib) {
+		tp->core_siblings[i] = buf;
+		tp->core_sib++;
+		buf = NULL;
+		len = 0;
+	}
+
+	sprintf(filename, THRD_SIB_FMT, cpu);
+	fp = fopen(filename, "r");
+	if (!fp)
+		goto done;
+
+	if (getline(&buf, &len, fp) <= 0)
+		goto done;
+
+	p = strchr(buf, '\n');
+	if (p)
+		*p = '\0';
+
+	for (i = 0; i < tp->thread_sib; i++) {
+		if (!strcmp(buf, tp->thread_siblings[i]))
+			break;
+	}
+	if (i == tp->thread_sib) {
+		tp->thread_siblings[i] = buf;
+		tp->thread_sib++;
+		buf = NULL;
+	}
+	ret = 0;
+done:
+	if(fp)
+		fclose(fp);
+	free(buf);
+	return ret;
+}
+
+static void free_cpu_topo(struct cpu_topo *tp)
+{
+	u32 i;
+
+	if (!tp)
+		return;
+
+	for (i = 0 ; i < tp->core_sib; i++)
+		free(tp->core_siblings[i]);
+
+	for (i = 0 ; i < tp->thread_sib; i++)
+		free(tp->thread_siblings[i]);
+
+	free(tp);
+}
+
+static struct cpu_topo *build_cpu_topology(void)
+{
+	struct cpu_topo *tp;
+	void *addr;
+	u32 nr, i;
+	size_t sz;
+	long ncpus;
+	int ret = -1;
+
+	ncpus = sysconf(_SC_NPROCESSORS_CONF);
+	if (ncpus < 0)
+		return NULL;
+
+	nr = (u32)(ncpus & UINT_MAX);
+
+	sz = nr * sizeof(char *);
+
+	addr = calloc(1, sizeof(*tp) + 2 * sz);
+	if (!addr)
+		return NULL;
+
+	tp = addr;
+
+	addr += sizeof(*tp);
+	tp->core_siblings = addr;
+	addr += sz;
+	tp->thread_siblings = addr;
+
+	for (i = 0; i < nr; i++) {
+		ret = build_cpu_topo(tp, i);
+		if (ret < 0)
+			break;
+	}
+	if (ret) {
+		free_cpu_topo(tp);
+		tp = NULL;
+	}
+	return tp;
+}
+
+static int write_cpu_topology(int fd, struct perf_header *h __used,
+			  struct perf_evlist *evlist __used)
+{
+	struct cpu_topo *tp;
+	u32 i;
+	int ret;
+
+	tp = build_cpu_topology();
+	if (!tp)
+		return -1;
+
+	ret = do_write(fd, &tp->core_sib, sizeof(tp->core_sib));
+	if (ret < 0)
+		goto done;
+
+	for (i = 0; i < tp->core_sib; i++) {
+		ret = do_write_string(fd, tp->core_siblings[i]);
+		if (ret < 0)
+			goto done;
+	}
+	ret = do_write(fd, &tp->thread_sib, sizeof(tp->thread_sib));
+	if (ret < 0)
+		goto done;
+
+	for (i = 0; i < tp->thread_sib; i++) {
+		ret = do_write_string(fd, tp->thread_siblings[i]);
+		if (ret < 0)
+			break;
+	}
+done:
+	free_cpu_topo(tp);
+	return ret;
+}
+
+
+
+static int write_total_mem(int fd, struct perf_header *h __used,
+			  struct perf_evlist *evlist __used)
+{
+	char *buf = NULL;
+	FILE *fp;
+	size_t len = 0;
+	int ret = -1, n;
+	uint64_t mem;
+
+	fp = fopen("/proc/meminfo", "r");
+	if (!fp)
+		return -1;
+
+	while (getline(&buf, &len, fp) > 0) {
+		ret = strncmp(buf, "MemTotal:", 9);
+		if (!ret)
+			break;
+	}
+	if (!ret) {
+		n = sscanf(buf, "%*s %"PRIu64, &mem);
+		if (n == 1)
+			ret = do_write(fd, &mem, sizeof(mem));
+	}
+	free(buf);
+	fclose(fp);
+	return ret;
+}
+
+static int write_topo_node(int fd, int node)
+{
+	char str[MAXPATHLEN];
+	char field[32];
+	char *buf = NULL, *p;
+	size_t len = 0;
+	FILE *fp;
+	u64 mem_total, mem_free, mem;
+	int ret = -1;
+
+	sprintf(str, "/sys/devices/system/node/node%d/meminfo", node);
+	fp = fopen(str, "r");
+	if (!fp)
+		return -1;
+
+	while (getline(&buf, &len, fp) > 0) {
+		/* skip over invalid lines */
+		if (!strchr(buf, ':'))
+			continue;
+		if (sscanf(buf, "%*s %*d %s %"PRIu64, field, &mem) != 2)
+			goto done;
+		if (!strcmp(field, "MemTotal:"))
+			mem_total = mem;
+		if (!strcmp(field, "MemFree:"))
+			mem_free = mem;
+	}
+
+	fclose(fp);
+
+	ret = do_write(fd, &mem_total, sizeof(u64));
+	if (ret)
+		goto done;
+
+	ret = do_write(fd, &mem_free, sizeof(u64));
+	if (ret)
+		goto done;
+
+	ret = -1;
+	sprintf(str, "/sys/devices/system/node/node%d/cpulist", node);
+
+	fp = fopen(str, "r");
+	if (!fp)
+		goto done;
+
+	if (getline(&buf, &len, fp) <= 0)
+		goto done;
+
+	p = strchr(buf, '\n');
+	if (p)
+		*p = '\0';
+
+	ret = do_write_string(fd, buf);
+done:
+	free(buf);
+	fclose(fp);
+	return ret;
+}
+
+static int write_numa_topology(int fd, struct perf_header *h __used,
+			  struct perf_evlist *evlist __used)
+{
+	char *buf = NULL;
+	size_t len = 0;
+	FILE *fp;
+	struct cpu_map *node_map = NULL;
+	char *c;
+	u32 nr, i, j;
+	int ret = -1;
+
+	fp = fopen("/sys/devices/system/node/online", "r");
+	if (!fp)
+		return -1;
+
+	if (getline(&buf, &len, fp) <= 0)
+		goto done;
+
+	c = strchr(buf, '\n');
+	if (c)
+		*c = '\0';
+
+	node_map = cpu_map__new(buf);
+	if (!node_map)
+		goto done;
+
+	nr = (u32)node_map->nr;
+
+	ret = do_write(fd, &nr, sizeof(nr));
+	if (ret < 0)
+		goto done;
+
+	for (i = 0; i < nr; i++) {
+		j = (u32)node_map->map[i];
+		ret = do_write(fd, &j, sizeof(j));
+		if (ret < 0)
+			break;
+
+		ret = write_topo_node(fd, i);
+		if (ret < 0)
+			break;
+	}
+done:
+	free(buf);
+	fclose(fp);
+	free(node_map);
+	return ret;
+}
+
+/*
+ * default get_cpuid(): nothing gets recorded
+ * actual implementation must be in arch/$(ARCH)/util/header.c
+ */
+int __attribute__((weak)) get_cpuid(char *buffer __used, size_t sz __used)
+{
+	return -1;
+}
+
+static int write_cpuid(int fd, struct perf_header *h __used,
+		       struct perf_evlist *evlist __used)
+{
+	char buffer[64];
+	int ret;
+
+	ret = get_cpuid(buffer, sizeof(buffer));
+	if (!ret)
+		goto write_it;
+
+	return -1;
+write_it:
+	return do_write_string(fd, buffer);
+}
+
+static int write_branch_stack(int fd __used, struct perf_header *h __used,
+		       struct perf_evlist *evlist __used)
+{
+	return 0;
+}
+
+static void print_hostname(struct perf_header *ph, int fd, FILE *fp)
+{
+	char *str = do_read_string(fd, ph);
+	fprintf(fp, "# hostname : %s\n", str);
+	free(str);
+}
+
+static void print_osrelease(struct perf_header *ph, int fd, FILE *fp)
+{
+	char *str = do_read_string(fd, ph);
+	fprintf(fp, "# os release : %s\n", str);
+	free(str);
+}
+
+static void print_arch(struct perf_header *ph, int fd, FILE *fp)
+{
+	char *str = do_read_string(fd, ph);
+	fprintf(fp, "# arch : %s\n", str);
+	free(str);
+}
+
+static void print_cpudesc(struct perf_header *ph, int fd, FILE *fp)
+{
+	char *str = do_read_string(fd, ph);
+	fprintf(fp, "# cpudesc : %s\n", str);
+	free(str);
+}
+
+static void print_nrcpus(struct perf_header *ph, int fd, FILE *fp)
+{
+	ssize_t ret;
+	u32 nr;
+
+	ret = read(fd, &nr, sizeof(nr));
+	if (ret != (ssize_t)sizeof(nr))
+		nr = -1; /* interpreted as error */
+
+	if (ph->needs_swap)
+		nr = bswap_32(nr);
+
+	fprintf(fp, "# nrcpus online : %u\n", nr);
+
+	ret = read(fd, &nr, sizeof(nr));
+	if (ret != (ssize_t)sizeof(nr))
+		nr = -1; /* interpreted as error */
+
+	if (ph->needs_swap)
+		nr = bswap_32(nr);
+
+	fprintf(fp, "# nrcpus avail : %u\n", nr);
+}
+
+static void print_version(struct perf_header *ph, int fd, FILE *fp)
+{
+	char *str = do_read_string(fd, ph);
+	fprintf(fp, "# perf version : %s\n", str);
+	free(str);
+}
+
+static void print_cmdline(struct perf_header *ph, int fd, FILE *fp)
+{
+	ssize_t ret;
+	char *str;
+	u32 nr, i;
+
+	ret = read(fd, &nr, sizeof(nr));
+	if (ret != (ssize_t)sizeof(nr))
+		return;
+
+	if (ph->needs_swap)
+		nr = bswap_32(nr);
+
+	fprintf(fp, "# cmdline : ");
+
+	for (i = 0; i < nr; i++) {
+		str = do_read_string(fd, ph);
+		fprintf(fp, "%s ", str);
+		free(str);
+	}
+	fputc('\n', fp);
+}
+
+static void print_cpu_topology(struct perf_header *ph, int fd, FILE *fp)
+{
+	ssize_t ret;
+	u32 nr, i;
+	char *str;
+
+	ret = read(fd, &nr, sizeof(nr));
+	if (ret != (ssize_t)sizeof(nr))
+		return;
+
+	if (ph->needs_swap)
+		nr = bswap_32(nr);
+
+	for (i = 0; i < nr; i++) {
+		str = do_read_string(fd, ph);
+		fprintf(fp, "# sibling cores   : %s\n", str);
+		free(str);
+	}
+
+	ret = read(fd, &nr, sizeof(nr));
+	if (ret != (ssize_t)sizeof(nr))
+		return;
+
+	if (ph->needs_swap)
+		nr = bswap_32(nr);
+
+	for (i = 0; i < nr; i++) {
+		str = do_read_string(fd, ph);
+		fprintf(fp, "# sibling threads : %s\n", str);
+		free(str);
+	}
+}
+
+static void print_event_desc(struct perf_header *ph, int fd, FILE *fp)
+{
+	struct perf_event_attr attr;
+	uint64_t id;
+	void *buf = NULL;
+	char *str;
+	u32 nre, sz, nr, i, j;
+	ssize_t ret;
+	size_t msz;
+
+	/* number of events */
+	ret = read(fd, &nre, sizeof(nre));
+	if (ret != (ssize_t)sizeof(nre))
+		goto error;
+
+	if (ph->needs_swap)
+		nre = bswap_32(nre);
+
+	ret = read(fd, &sz, sizeof(sz));
+	if (ret != (ssize_t)sizeof(sz))
+		goto error;
+
+	if (ph->needs_swap)
+		sz = bswap_32(sz);
+
+	memset(&attr, 0, sizeof(attr));
+
+	/* buffer to hold on file attr struct */
+	buf = malloc(sz);
+	if (!buf)
+		goto error;
+
+	msz = sizeof(attr);
+	if (sz < msz)
+		msz = sz;
+
+	for (i = 0 ; i < nre; i++) {
+
+		/*
+		 * must read entire on-file attr struct to
+		 * sync up with layout.
+		 */
+		ret = read(fd, buf, sz);
+		if (ret != (ssize_t)sz)
+			goto error;
+
+		if (ph->needs_swap)
+			perf_event__attr_swap(buf);
+
+		memcpy(&attr, buf, msz);
+
+		ret = read(fd, &nr, sizeof(nr));
+		if (ret != (ssize_t)sizeof(nr))
+			goto error;
+
+		if (ph->needs_swap)
+			nr = bswap_32(nr);
+
+		str = do_read_string(fd, ph);
+		fprintf(fp, "# event : name = %s, ", str);
+		free(str);
+
+		fprintf(fp, "type = %d, config = 0x%"PRIx64
+			    ", config1 = 0x%"PRIx64", config2 = 0x%"PRIx64,
+				attr.type,
+				(u64)attr.config,
+				(u64)attr.config1,
+				(u64)attr.config2);
+
+		fprintf(fp, ", excl_usr = %d, excl_kern = %d",
+				attr.exclude_user,
+				attr.exclude_kernel);
+
+		if (nr)
+			fprintf(fp, ", id = {");
+
+		for (j = 0 ; j < nr; j++) {
+			ret = read(fd, &id, sizeof(id));
+			if (ret != (ssize_t)sizeof(id))
+				goto error;
+
+			if (ph->needs_swap)
+				id = bswap_64(id);
+
+			if (j)
+				fputc(',', fp);
+
+			fprintf(fp, " %"PRIu64, id);
+		}
+		if (nr && j == nr)
+			fprintf(fp, " }");
+		fputc('\n', fp);
+	}
+	free(buf);
+	return;
+error:
+	fprintf(fp, "# event desc: not available or unable to read\n");
+}
+
+static void print_total_mem(struct perf_header *h __used, int fd, FILE *fp)
+{
+	uint64_t mem;
+	ssize_t ret;
+
+	ret = read(fd, &mem, sizeof(mem));
+	if (ret != sizeof(mem))
+		goto error;
+
+	if (h->needs_swap)
+		mem = bswap_64(mem);
+
+	fprintf(fp, "# total memory : %"PRIu64" kB\n", mem);
+	return;
+error:
+	fprintf(fp, "# total memory : unknown\n");
+}
+
+static void print_numa_topology(struct perf_header *h __used, int fd, FILE *fp)
+{
+	ssize_t ret;
+	u32 nr, c, i;
+	char *str;
+	uint64_t mem_total, mem_free;
+
+	/* nr nodes */
+	ret = read(fd, &nr, sizeof(nr));
+	if (ret != (ssize_t)sizeof(nr))
+		goto error;
+
+	if (h->needs_swap)
+		nr = bswap_32(nr);
+
+	for (i = 0; i < nr; i++) {
+
+		/* node number */
+		ret = read(fd, &c, sizeof(c));
+		if (ret != (ssize_t)sizeof(c))
+			goto error;
+
+		if (h->needs_swap)
+			c = bswap_32(c);
+
+		ret = read(fd, &mem_total, sizeof(u64));
+		if (ret != sizeof(u64))
+			goto error;
+
+		ret = read(fd, &mem_free, sizeof(u64));
+		if (ret != sizeof(u64))
+			goto error;
+
+		if (h->needs_swap) {
+			mem_total = bswap_64(mem_total);
+			mem_free = bswap_64(mem_free);
+		}
+
+		fprintf(fp, "# node%u meminfo  : total = %"PRIu64" kB,"
+			    " free = %"PRIu64" kB\n",
+			c,
+			mem_total,
+			mem_free);
+
+		str = do_read_string(fd, h);
+		fprintf(fp, "# node%u cpu list : %s\n", c, str);
+		free(str);
+	}
+	return;
+error:
+	fprintf(fp, "# numa topology : not available\n");
+}
+
+static void print_cpuid(struct perf_header *ph, int fd, FILE *fp)
+{
+	char *str = do_read_string(fd, ph);
+	fprintf(fp, "# cpuid : %s\n", str);
+	free(str);
+}
+
+static void print_branch_stack(struct perf_header *ph __used, int fd __used,
+			       FILE *fp)
+{
+	fprintf(fp, "# contains samples with branch stack\n");
+}
+
+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;
+
+		/*
+		 * As the pid is the missing value, we need to fill
+		 * it properly. The header.misc value give us nice hint.
+		 */
+		bev.pid	= HOST_KERNEL_ID;
+		if (bev.header.misc == PERF_RECORD_MISC_GUEST_USER ||
+		    bev.header.misc == PERF_RECORD_MISC_GUEST_KERNEL)
+			bev.pid	= DEFAULT_GUEST_KERNEL_ID;
+
+		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 process_trace_info(struct perf_file_section *section __unused,
+			      struct perf_header *ph __unused,
+			      int feat __unused, int fd)
+{
+	trace_report(fd, false);
+	return 0;
+}
+
+static int process_build_id(struct perf_file_section *section,
+			    struct perf_header *ph,
+			    int feat __unused, int fd)
+{
+	if (perf_header__read_build_ids(ph, fd, section->offset, section->size))
+		pr_debug("Failed to read buildids, continuing...\n");
+	return 0;
+}
+
+struct feature_ops {
+	int (*write)(int fd, struct perf_header *h, struct perf_evlist *evlist);
+	void (*print)(struct perf_header *h, int fd, FILE *fp);
+	int (*process)(struct perf_file_section *section,
+		       struct perf_header *h, int feat, int fd);
+	const char *name;
+	bool full_only;
+};
+
+#define FEAT_OPA(n, func) \
+	[n] = { .name = #n, .write = write_##func, .print = print_##func }
+#define FEAT_OPP(n, func) \
+	[n] = { .name = #n, .write = write_##func, .print = print_##func, \
+		.process = process_##func }
+#define FEAT_OPF(n, func) \
+	[n] = { .name = #n, .write = write_##func, .print = print_##func, \
+		.full_only = true }
+
+/* feature_ops not implemented: */
+#define print_trace_info		NULL
+#define print_build_id			NULL
+
+static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
+	FEAT_OPP(HEADER_TRACE_INFO,	trace_info),
+	FEAT_OPP(HEADER_BUILD_ID,	build_id),
+	FEAT_OPA(HEADER_HOSTNAME,	hostname),
+	FEAT_OPA(HEADER_OSRELEASE,	osrelease),
+	FEAT_OPA(HEADER_VERSION,	version),
+	FEAT_OPA(HEADER_ARCH,		arch),
+	FEAT_OPA(HEADER_NRCPUS,		nrcpus),
+	FEAT_OPA(HEADER_CPUDESC,	cpudesc),
+	FEAT_OPA(HEADER_CPUID,		cpuid),
+	FEAT_OPA(HEADER_TOTAL_MEM,	total_mem),
+	FEAT_OPA(HEADER_EVENT_DESC,	event_desc),
+	FEAT_OPA(HEADER_CMDLINE,	cmdline),
+	FEAT_OPF(HEADER_CPU_TOPOLOGY,	cpu_topology),
+	FEAT_OPF(HEADER_NUMA_TOPOLOGY,	numa_topology),
+	FEAT_OPA(HEADER_BRANCH_STACK,	branch_stack),
+};
+
+struct header_print_data {
+	FILE *fp;
+	bool full; /* extended list of headers */
+};
+
+static int perf_file_section__fprintf_info(struct perf_file_section *section,
+					   struct perf_header *ph,
+					   int feat, int fd, void *data)
+{
+	struct header_print_data *hd = data;
+
+	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;
+	}
+	if (feat >= HEADER_LAST_FEATURE) {
+		pr_warning("unknown feature %d\n", feat);
+		return 0;
+	}
+	if (!feat_ops[feat].print)
+		return 0;
+
+	if (!feat_ops[feat].full_only || hd->full)
+		feat_ops[feat].print(ph, fd, hd->fp);
+	else
+		fprintf(hd->fp, "# %s info available, use -I to display\n",
+			feat_ops[feat].name);
+
+	return 0;
+}
+
+int perf_header__fprintf_info(struct perf_session *session, FILE *fp, bool full)
+{
+	struct header_print_data hd;
+	struct perf_header *header = &session->header;
+	int fd = session->fd;
+	hd.fp = fp;
+	hd.full = full;
+
+	perf_header__process_sections(header, fd, &hd,
+				      perf_file_section__fprintf_info);
+	return 0;
+}
+
+static int do_write_feat(int fd, struct perf_header *h, int type,
+			 struct perf_file_section **p,
+			 struct perf_evlist *evlist)
+{
+	int err;
+	int ret = 0;
+
+	if (perf_header__has_feat(h, type)) {
+		if (!feat_ops[type].write)
+			return -1;
+
+		(*p)->offset = lseek(fd, 0, SEEK_CUR);
+
+		err = feat_ops[type].write(fd, h, evlist);
+		if (err < 0) {
+			pr_debug("failed to write feature %d\n", type);
+
+			/* undo anything written */
+			lseek(fd, (*p)->offset, SEEK_SET);
+
+			return -1;
+		}
+		(*p)->size = lseek(fd, 0, SEEK_CUR) - (*p)->offset;
+		(*p)++;
+	}
+	return ret;
+}
+
+static int perf_header__adds_write(struct perf_header *header,
+				   struct perf_evlist *evlist, int fd)
+{
+	int nr_sections;
+	struct perf_file_section *feat_sec, *p;
+	int sec_size;
+	u64 sec_start;
+	int feat;
+	int err;
+
+	nr_sections = bitmap_weight(header->adds_features, HEADER_FEAT_BITS);
+	if (!nr_sections)
+		return 0;
+
+	feat_sec = p = 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);
+
+	for_each_set_bit(feat, header->adds_features, HEADER_FEAT_BITS) {
+		if (do_write_feat(fd, header, feat, &p, evlist))
+			perf_header__clear_feat(header, feat);
+	}
+
+	lseek(fd, sec_start, SEEK_SET);
+	/*
+	 * may write more than needed due to dropped feature, but
+	 * this is okay, reader will skip the mising entries
+	 */
+	err = do_write(fd, feat_sec, sec_size);
+	if (err < 0)
+		pr_debug("failed to write feature section\n");
+	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,
+				  void *data,
+				  int (*process)(struct perf_file_section *section,
+						 struct perf_header *ph,
+						 int feat, int fd, void *data))
+{
+	struct perf_file_section *feat_sec, *sec;
+	int nr_sections;
+	int sec_size;
+	int feat;
+	int err;
+
+	nr_sections = bitmap_weight(header->adds_features, HEADER_FEAT_BITS);
+	if (!nr_sections)
+		return 0;
+
+	feat_sec = 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);
+
+	err = perf_header__getbuffer64(header, fd, feat_sec, sec_size);
+	if (err < 0)
+		goto out_free;
+
+	for_each_set_bit(feat, header->adds_features, HEADER_LAST_FEATURE) {
+		err = process(sec++, header, feat, fd, data);
+		if (err < 0)
+			goto out_free;
+	}
+	err = 0;
+out_free:
+	free(feat_sec);
+	return err;
+}
+
+static const int attr_file_abi_sizes[] = {
+	[0] = PERF_ATTR_SIZE_VER0,
+	[1] = PERF_ATTR_SIZE_VER1,
+	0,
+};
+
+/*
+ * In the legacy file format, the magic number is not used to encode endianness.
+ * hdr_sz was used to encode endianness. But given that hdr_sz can vary based
+ * on ABI revisions, we need to try all combinations for all endianness to
+ * detect the endianness.
+ */
+static int try_all_file_abis(uint64_t hdr_sz, struct perf_header *ph)
+{
+	uint64_t ref_size, attr_size;
+	int i;
+
+	for (i = 0 ; attr_file_abi_sizes[i]; i++) {
+		ref_size = attr_file_abi_sizes[i]
+			 + sizeof(struct perf_file_section);
+		if (hdr_sz != ref_size) {
+			attr_size = bswap_64(hdr_sz);
+			if (attr_size != ref_size)
+				continue;
+
+			ph->needs_swap = true;
+		}
+		pr_debug("ABI%d perf.data file detected, need_swap=%d\n",
+			 i,
+			 ph->needs_swap);
+		return 0;
+	}
+	/* could not determine endianness */
+	return -1;
+}
+
+#define PERF_PIPE_HDR_VER0	16
+
+static const size_t attr_pipe_abi_sizes[] = {
+	[0] = PERF_PIPE_HDR_VER0,
+	0,
+};
+
+/*
+ * In the legacy pipe format, there is an implicit assumption that endiannesss
+ * between host recording the samples, and host parsing the samples is the
+ * same. This is not always the case given that the pipe output may always be
+ * redirected into a file and analyzed on a different machine with possibly a
+ * different endianness and perf_event ABI revsions in the perf tool itself.
+ */
+static int try_all_pipe_abis(uint64_t hdr_sz, struct perf_header *ph)
+{
+	u64 attr_size;
+	int i;
+
+	for (i = 0 ; attr_pipe_abi_sizes[i]; i++) {
+		if (hdr_sz != attr_pipe_abi_sizes[i]) {
+			attr_size = bswap_64(hdr_sz);
+			if (attr_size != hdr_sz)
+				continue;
+
+			ph->needs_swap = true;
+		}
+		pr_debug("Pipe ABI%d perf.data file detected\n", i);
+		return 0;
+	}
+	return -1;
+}
+
+static int check_magic_endian(u64 magic, uint64_t hdr_sz,
+			      bool is_pipe, struct perf_header *ph)
+{
+	int ret;
+
+	/* check for legacy format */
+	ret = memcmp(&magic, __perf_magic1, sizeof(magic));
+	if (ret == 0) {
+		pr_debug("legacy perf.data format\n");
+		if (is_pipe)
+			return try_all_pipe_abis(hdr_sz, ph);
+
+		return try_all_file_abis(hdr_sz, ph);
+	}
+	/*
+	 * the new magic number serves two purposes:
+	 * - unique number to identify actual perf.data files
+	 * - encode endianness of file
+	 */
+
+	/* check magic number with one endianness */
+	if (magic == __perf_magic2)
+		return 0;
+
+	/* check magic number with opposite endianness */
+	if (magic != __perf_magic2_sw)
+		return -1;
+
+	ph->needs_swap = true;
+
+	return 0;
+}
+
+int perf_file_header__read(struct perf_file_header *header,
+			   struct perf_header *ph, int fd)
+{
+	int ret;
+
+	lseek(fd, 0, SEEK_SET);
+
+	ret = readn(fd, header, sizeof(*header));
+	if (ret <= 0)
+		return -1;
+
+	if (check_magic_endian(header->magic,
+			       header->attr_size, false, ph) < 0) {
+		pr_debug("magic/endian check failed\n");
+		return -1;
+	}
+
+	if (ph->needs_swap) {
+		mem_bswap_64(header, offsetof(struct perf_file_header,
+			     adds_features));
+	}
+
+	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;
+	} else if (ph->needs_swap) {
+		unsigned int i;
+		/*
+		 * feature bitmap is declared as an array of unsigned longs --
+		 * not good since its size can differ between the host that
+		 * generated the data file and the host analyzing the file.
+		 *
+		 * We need to handle endianness, but we don't know the size of
+		 * the unsigned long where the file was generated. Take a best
+		 * guess at determining it: try 64-bit swap first (ie., file
+		 * created on a 64-bit host), and check if the hostname feature
+		 * bit is set (this feature bit is forced on as of fbe96f2).
+		 * If the bit is not, undo the 64-bit swap and try a 32-bit
+		 * swap. If the hostname bit is still not set (e.g., older data
+		 * file), punt and fallback to the original behavior --
+		 * clearing all feature bits and setting buildid.
+		 */
+		for (i = 0; i < BITS_TO_LONGS(HEADER_FEAT_BITS); ++i)
+			header->adds_features[i] = bswap_64(header->adds_features[i]);
+
+		if (!test_bit(HEADER_HOSTNAME, header->adds_features)) {
+			for (i = 0; i < BITS_TO_LONGS(HEADER_FEAT_BITS); ++i) {
+				header->adds_features[i] = bswap_64(header->adds_features[i]);
+				header->adds_features[i] = bswap_32(header->adds_features[i]);
+			}
+		}
+
+		if (!test_bit(HEADER_HOSTNAME, header->adds_features)) {
+			bitmap_zero(header->adds_features, HEADER_FEAT_BITS);
+			set_bit(HEADER_BUILD_ID, header->adds_features);
+		}
+	}
+
+	memcpy(&ph->adds_features, &header->adds_features,
+	       sizeof(ph->adds_features));
+
+	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 perf_file_section__process(struct perf_file_section *section,
+				      struct perf_header *ph,
+				      int feat, int fd, void *data __used)
+{
+	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;
+	}
+
+	if (feat >= HEADER_LAST_FEATURE) {
+		pr_debug("unknown feature %d, continuing...\n", feat);
+		return 0;
+	}
+
+	if (!feat_ops[feat].process)
+		return 0;
+
+	return feat_ops[feat].process(section, ph, feat, fd);
+}
+
+static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
+				       struct perf_header *ph, int fd,
+				       bool repipe)
+{
+	int ret;
+
+	ret = readn(fd, header, sizeof(*header));
+	if (ret <= 0)
+		return -1;
+
+	if (check_magic_endian(header->magic, header->size, true, ph) < 0) {
+		pr_debug("endian/magic failed\n");
+		return -1;
+	}
+
+	if (ph->needs_swap)
+		header->size = bswap_64(header->size);
+
+	if (repipe && do_write(STDOUT_FILENO, header, sizeof(*header)) < 0)
+		return -1;
+
+	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;
+}
+
+static int read_attr(int fd, struct perf_header *ph,
+		     struct perf_file_attr *f_attr)
+{
+	struct perf_event_attr *attr = &f_attr->attr;
+	size_t sz, left;
+	size_t our_sz = sizeof(f_attr->attr);
+	int ret;
+
+	memset(f_attr, 0, sizeof(*f_attr));
+
+	/* read minimal guaranteed structure */
+	ret = readn(fd, attr, PERF_ATTR_SIZE_VER0);
+	if (ret <= 0) {
+		pr_debug("cannot read %d bytes of header attr\n",
+			 PERF_ATTR_SIZE_VER0);
+		return -1;
+	}
+
+	/* on file perf_event_attr size */
+	sz = attr->size;
+
+	if (ph->needs_swap)
+		sz = bswap_32(sz);
+
+	if (sz == 0) {
+		/* assume ABI0 */
+		sz =  PERF_ATTR_SIZE_VER0;
+	} else if (sz > our_sz) {
+		pr_debug("file uses a more recent and unsupported ABI"
+			 " (%zu bytes extra)\n", sz - our_sz);
+		return -1;
+	}
+	/* what we have not yet read and that we know about */
+	left = sz - PERF_ATTR_SIZE_VER0;
+	if (left) {
+		void *ptr = attr;
+		ptr += PERF_ATTR_SIZE_VER0;
+
+		ret = readn(fd, ptr, left);
+	}
+	/* read perf_file_section, ids are read in caller */
+	ret = readn(fd, &f_attr->ids, sizeof(f_attr->ids));
+
+	return ret <= 0 ? -1 : 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)
+		return -EINVAL;
+
+	nr_attrs = f_header.attrs.size / f_header.attr_size;
+	lseek(fd, f_header.attrs.offset, SEEK_SET);
+
+	for (i = 0; i < nr_attrs; i++) {
+		struct perf_evsel *evsel;
+		off_t tmp;
+
+		if (read_attr(fd, header, &f_attr) < 0)
+			goto out_errno;
+
+		if (header->needs_swap)
+			perf_event__attr_swap(&f_attr.attr);
+
+		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);
+	}
+
+	symbol_conf.nr_events = nr_attrs;
+
+	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, NULL,
+				      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_tool *tool,
+				struct perf_event_attr *attr, u16 ids, u64 *id,
+				perf_event__handler_t process)
+{
+	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(tool, ev, NULL, NULL);
+
+	free(ev);
+
+	return err;
+}
+
+int perf_event__synthesize_attrs(struct perf_tool *tool,
+				   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(tool, &attr->attr, attr->ids,
+						  attr->id, process);
+		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_evlist **pevlist)
+{
+	unsigned int i, ids, n_ids;
+	struct perf_evsel *evsel;
+	struct perf_evlist *evlist = *pevlist;
+
+	if (evlist == NULL) {
+		*pevlist = evlist = perf_evlist__new(NULL, NULL);
+		if (evlist == NULL)
+			return -ENOMEM;
+	}
+
+	evsel = perf_evsel__new(&event->attr.attr, evlist->nr_entries);
+	if (evsel == NULL)
+		return -ENOMEM;
+
+	perf_evlist__add(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(evlist, evsel, 0, i, event->attr.id[i]);
+	}
+
+	return 0;
+}
+
+int perf_event__synthesize_event_type(struct perf_tool *tool,
+				      u64 event_id, char *name,
+				      perf_event__handler_t process,
+				      struct machine *machine)
+{
+	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(ev.event_type.event_type.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(tool, &ev, NULL, machine);
+
+	return err;
+}
+
+int perf_event__synthesize_event_types(struct perf_tool *tool,
+				       perf_event__handler_t process,
+				       struct machine *machine)
+{
+	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(tool, type->event_id,
+							type->name, process,
+							machine);
+		if (err) {
+			pr_debug("failed to create perf header event type\n");
+			return err;
+		}
+	}
+
+	return err;
+}
+
+int perf_event__process_event_type(struct perf_tool *tool __unused,
+				   union perf_event *event)
+{
+	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(struct perf_tool *tool, int fd,
+					struct perf_evlist *evlist,
+					perf_event__handler_t process)
+{
+	union perf_event ev;
+	struct tracing_data *tdata;
+	ssize_t size = 0, aligned_size = 0, padding;
+	int err __used = 0;
+
+	/*
+	 * We are going to store the size of the data followed
+	 * by the data contents. Since the fd descriptor is a pipe,
+	 * we cannot seek back to store the size of the data once
+	 * we know it. Instead we:
+	 *
+	 * - write the tracing data to the temp file
+	 * - get/write the data size to pipe
+	 * - write the tracing data from the temp file
+	 *   to the pipe
+	 */
+	tdata = tracing_data_get(&evlist->entries, fd, true);
+	if (!tdata)
+		return -1;
+
+	memset(&ev, 0, sizeof(ev));
+
+	ev.tracing_data.header.type = PERF_RECORD_HEADER_TRACING_DATA;
+	size = tdata->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(tool, &ev, NULL, NULL);
+
+	/*
+	 * The put function will copy all the tracing data
+	 * stored in temp file to the pipe.
+	 */
+	tracing_data_put(tdata);
+
+	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 perf_tool *tool,
+				    struct dso *pos, u16 misc,
+				    perf_event__handler_t process,
+				    struct machine *machine)
+{
+	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(tool, &ev, NULL, machine);
+
+	return err;
+}
+
+int perf_event__process_build_id(struct perf_tool *tool __used,
+				 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;
+}