Documentation/filesystems

/*
 * builtin-annotate.c
 *
 * Builtin annotate command: Analyze the perf.data input file,
 * look up and read DSOs and symbol information and display
 * a histogram of results, along various sorting keys.
 */
#include "builtin.h"

#include "util/util.h"

#include "util/color.h"
#include <linux/list.h>
#include "util/cache.h"
#include <linux/rbtree.h>
#include "util/symbol.h"
#include "util/string.h"

#include "perf.h"
#include "util/debug.h"

#include "util/parse-options.h"
#include "util/parse-events.h"
#include "util/thread.h"
#include "util/sort.h"
#include "util/hist.h"
#include "util/process_events.h"

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

static int		force;
static int		input;

static int		full_paths;

static int		print_line;

static unsigned long	page_size;
static unsigned long	mmap_window = 32;

struct sym_hist {
	u64		sum;
	u64		ip[0];
};

struct sym_ext {
	struct rb_node	node;
	double		percent;
	char		*path;
};

struct sym_priv {
	struct sym_hist	*hist;
	struct sym_ext	*ext;
};

static struct symbol_conf symbol_conf = {
	.priv_size	  = sizeof(struct sym_priv),
	.try_vmlinux_path = true,
};

static const char *sym_hist_filter;

static int symbol_filter(struct map *map __used, struct symbol *sym)
{
	if (sym_hist_filter == NULL ||
	    strcmp(sym->name, sym_hist_filter) == 0) {
		struct sym_priv *priv = symbol__priv(sym);
		const int size = (sizeof(*priv->hist) +
				  (sym->end - sym->start) * sizeof(u64));

		priv->hist = malloc(size);
		if (priv->hist)
			memset(priv->hist, 0, size);
		return 0;
	}
	/*
	 * FIXME: We should really filter it out, as we don't want to go thru symbols
	 * we're not interested, and if a DSO ends up with no symbols, delete it too,
	 * but right now the kernel loading routines in symbol.c bail out if no symbols
	 * are found, fix it later.
	 */
	return 0;
}

/*
 * collect histogram counts
 */
static void hist_hit(struct hist_entry *he, u64 ip)
{
	unsigned int sym_size, offset;
	struct symbol *sym = he->sym;
	struct sym_priv *priv;
	struct sym_hist *h;

	he->count++;

	if (!sym || !he->map)
		return;

	priv = symbol__priv(sym);
	if (!priv->hist)
		return;

	sym_size = sym->end - sym->start;
	offset = ip - sym->start;

	if (verbose)
		fprintf(stderr, "%s: ip=%Lx\n", __func__,
			he->map->unmap_ip(he->map, ip));

	if (offset >= sym_size)
		return;

	h = priv->hist;
	h->sum++;
	h->ip[offset]++;

	if (verbose >= 3)
		printf("%p %s: count++ [ip: %p, %08Lx] => %Ld\n",
			(void *)(unsigned long)he->sym->start,
			he->sym->name,
			(void *)(unsigned long)ip, ip - he->sym->start,
			h->ip[offset]);
}

static int hist_entry__add(struct thread *thread, struct map *map,
			   struct symbol *sym, u64 ip, u64 count, char level)
{
	bool hit;
	struct hist_entry *he = __hist_entry__add(thread, map, sym, NULL, ip,
						  count, level, &hit);
	if (he == NULL)
		return -ENOMEM;
	hist_hit(he, ip);
	return 0;
}

static int
process_sample_event(event_t *event, unsigned long offset, unsigned long head)
{
	char level;
	u64 ip = event->ip.ip;
	struct map *map = NULL;
	struct symbol *sym = NULL;
	struct thread *thread = threads__findnew(event->ip.pid);

	dump_printf("%p [%p]: PERF_EVENT (IP, %d): %d: %p\n",
		(void *)(offset + head),
		(void *)(long)(event->header.size),
		event->header.misc,
		event->ip.pid,
		(void *)(long)ip);

	if (thread == NULL) {
		fprintf(stderr, "problem processing %d event, skipping it.\n",
			event->header.type);
		return -1;
	}

	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);

	if (event->header.misc & PERF_RECORD_MISC_KERNEL) {
		level = 'k';
		sym = kernel_maps__find_function(ip, &map, symbol_filter);
		dump_printf(" ...... dso: %s\n",
			    map ? map->dso->long_name : "<not found>");
	} else if (event->header.misc & PERF_RECORD_MISC_USER) {
		level = '.';
		map = thread__find_map(thread, ip);
		if (map != NULL) {
got_map:
			ip = map->map_ip(map, ip);
			sym = map__find_function(map, ip, symbol_filter);
		} else {
			/*
			 * If this is outside of all known maps,
			 * and is a negative address, try to look it
			 * up in the kernel dso, as it might be a
			 * vsyscall or vdso (which executes in user-mode).
			 *
			 * XXX This is nasty, we should have a symbol list in
			 * the "[vdso]" dso, but for now lets use the old
			 * trick of looking in the whole kernel symbol list.
			 */
			if ((long long)ip < 0) {
				map = kernel_map__functions;
				goto got_map;
			}
		}
		dump_printf(" ...... dso: %s\n",
			    map ? map->dso->long_name : "<not found>");
	} else {
		level = 'H';
		dump_printf(" ...... dso: [hypervisor]\n");
	}

	if (hist_entry__add(thread, map, sym, ip, 1, level)) {
		fprintf(stderr, "problem incrementing symbol count, "
				"skipping event\n");
		return -1;
	}
	total++;

	return 0;
}

static int
process_comm_event(event_t *event, unsigned long offset, unsigned long head)
{
	struct thread *thread = threads__findnew(event->comm.pid);

	dump_printf("%p [%p]: PERF_RECORD_COMM: %s:%d\n",
		(void *)(offset + head),
		(void *)(long)(event->header.size),
		event->comm.comm, event->comm.pid);

	if (thread == NULL ||
	    thread__set_comm(thread, event->comm.comm)) {
		dump_printf("problem processing PERF_RECORD_COMM, skipping event.\n");
		return -1;
	}
	total_comm++;

	return 0;
}

static int
process_event(event_t *event, unsigned long offset, unsigned long head)
{
	switch (event->header.type) {
	case PERF_RECORD_SAMPLE:
		return process_sample_event(event, offset, head);

	case PERF_RECORD_MMAP:
		return process_mmap_event(event, offset, head);

	case PERF_RECORD_COMM:
		return process_comm_event(event, offset, head);

	case PERF_RECORD_FORK:
		return process_task_event(event, offset, head);
	/*
	 * We dont process them right now but they are fine:
	 */

	case PERF_RECORD_THROTTLE:
	case PERF_RECORD_UNTHROTTLE:
		return 0;

	default:
		return -1;
	}

	return 0;
}

static int parse_line(FILE *file, struct hist_entry *he, u64 len)
{
	struct symbol *sym = he->sym;
	char *line = NULL, *tmp, *tmp2;
	static const char *prev_line;
	static const char *prev_color;
	unsigned int offset;
	size_t line_len;
	u64 start;
	s64 line_ip;
	int ret;
	char *c;

	if (getline(&line, &line_len, file) < 0)
		return -1;
	if (!line)
		return -1;

	c = strchr(line, '\n');
	if (c)
		*c = 0;

	line_ip = -1;
	offset = 0;
	ret = -2;

	/*
	 * Strip leading spaces:
	 */
	tmp = line;
	while (*tmp) {
		if (*tmp != ' ')
			break;
		tmp++;
	}

	if (*tmp) {
		/*
		 * Parse hexa addresses followed by ':'
		 */
		line_ip = strtoull(tmp, &tmp2, 16);
		if (*tmp2 != ':')
			line_ip = -1;
	}

	start = he->map->unmap_ip(he->map, sym->start);

	if (line_ip != -1) {
		const char *path = NULL;
		unsigned int hits = 0;
		double percent = 0.0;
		const char *color;
		struct sym_priv *priv = symbol__priv(sym);
		struct sym_ext *sym_ext = priv->ext;
		struct sym_hist *h = priv->hist;

		offset = line_ip - start;
		if (offset < len)
			hits = h->ip[offset];

		if (offset < len && sym_ext) {
			path = sym_ext[offset].path;
			percent = sym_ext[offset].percent;
		} else if (h->sum)
			percent = 100.0 * hits / h->sum;

		color = get_percent_color(percent);

		/*
		 * Also color the filename and line if needed, with
		 * the same color than the percentage. Don't print it
		 * twice for close colored ip with the same filename:line
		 */
		if (path) {
			if (!prev_line || strcmp(prev_line, path)
				       || color != prev_color) {
				color_fprintf(stdout, color, " %s", path);
				prev_line = path;
				prev_color = color;
			}
		}

		color_fprintf(stdout, color, " %7.2f", percent);
		printf(" :	");
		color_fprintf(stdout, PERF_COLOR_BLUE, "%s\n", line);
	} else {
		if (!*line)
			printf("         :\n");
		else
			printf("         :	%s\n", line);
	}

	return 0;
}

static struct rb_root root_sym_ext;

static void insert_source_line(struct sym_ext *sym_ext)
{
	struct sym_ext *iter;
	struct rb_node **p = &root_sym_ext.rb_node;
	struct rb_node *parent = NULL;

	while (*p != NULL) {
		parent = *p;
		iter = rb_entry(parent, struct sym_ext, node);

		if (sym_ext->percent > iter->percent)
			p = &(*p)->rb_left;
		else
			p = &(*p)->rb_right;
	}

	rb_link_node(&sym_ext->node, parent, p);
	rb_insert_color(&sym_ext->node, &root_sym_ext);
}

static void free_source_line(struct hist_entry *he, int len)
{
	struct sym_priv *priv = symbol__priv(he->sym);
	struct sym_ext *sym_ext = priv->ext;
	int i;

	if (!sym_ext)
		return;

	for (i = 0; i < len; i++)
		free(sym_ext[i].path);
	free(sym_ext);

	priv->ext = NULL;
	root_sym_ext = RB_ROOT;
}

/* Get the filename:line for the colored entries */
static void
get_source_line(struct hist_entry *he, int len, const char *filename)
{
	struct symbol *sym = he->sym;
	u64 start;
	int i;
	char cmd[PATH_MAX * 2];
	struct sym_ext *sym_ext;
	struct sym_priv *priv = symbol__priv(sym);
	struct sym_hist *h = priv->hist;

	if (!h->sum)
		return;

	sym_ext = priv->ext = calloc(len, sizeof(struct sym_ext));
	if (!priv->ext)
		return;

	start = he->map->unmap_ip(he->map, sym->start);

	for (i = 0; i < len; i++) {
		char *path = NULL;
		size_t line_len;
		u64 offset;
		FILE *fp;

		sym_ext[i].percent = 100.0 * h->ip[i] / h->sum;
		if (sym_ext[i].percent <= 0.5)
			continue;

		offset = start + i;
		sprintf(cmd, "addr2line -e %s %016llx", filename, offset);
		fp = popen(cmd, "r");
		if (!fp)
			continue;

		if (getline(&path, &line_len, fp) < 0 || !line_len)
			goto next;

		sym_ext[i].path = malloc(sizeof(char) * line_len + 1);
		if (!sym_ext[i].path)
			goto next;

		strcpy(sym_ext[i].path, path);
		insert_source_line(&sym_ext[i]);

	next:
		pclose(fp);
	}
}

static void print_summary(const char *filename)
{
	struct sym_ext *sym_ext;
	struct rb_node *node;

	printf("\nSorted summary for file %s\n", filename);
	printf("----------------------------------------------\n\n");

	if (RB_EMPTY_ROOT(&root_sym_ext)) {
		printf(" Nothing higher than %1.1f%%\n", MIN_GREEN);
		return;
	}

	node = rb_first(&root_sym_ext);
	while (node) {
		double percent;
		const char *color;
		char *path;

		sym_ext = rb_entry(node, struct sym_ext, node);
		percent = sym_ext->percent;
		color = get_percent_color(percent);
		path = sym_ext->path;

		color_fprintf(stdout, color, " %7.2f %s", percent, path);
		node = rb_next(node);
	}
}

static void annotate_sym(struct hist_entry *he)
{
	struct map *map = he->map;
	struct dso *dso = map->dso;
	struct symbol *sym = he->sym;
	const char *filename = dso->long_name, *d_filename;
	u64 len;
	char command[PATH_MAX*2];
	FILE *file;

	if (!filename)
		return;

	if (verbose)
		fprintf(stderr, "%s: filename=%s, sym=%s, start=%Lx, end=%Lx\n",
			__func__, filename, sym->name,
			map->unmap_ip(map, sym->start),
			map->unmap_ip(map, sym->end));

	if (full_paths)
		d_filename = filename;
	else
		d_filename = basename(filename);

	len = sym->end - sym->start;

	if (print_line) {
		get_source_line(he, len, filename);
		print_summary(filename);
	}

	printf("\n\n------------------------------------------------\n");
	printf(" Percent |	Source code & Disassembly of %s\n", d_filename);
	printf("------------------------------------------------\n");

	if (verbose >= 2)
		printf("annotating [%p] %30s : [%p] %30s\n",
		       dso, dso->long_name, sym, sym->name);

	sprintf(command, "objdump --start-address=0x%016Lx --stop-address=0x%016Lx -dS %s|grep -v %s",
		map->unmap_ip(map, sym->start), map->unmap_ip(map, sym->end),
		filename, filename);

	if (verbose >= 3)
		printf("doing: %s\n", command);

	file = popen(command, "r");
	if (!file)
		return;

	while (!feof(file)) {
		if (parse_line(file, he, len) < 0)
			break;
	}

	pclose(file);
	if (print_line)
		free_source_line(he, len);
}

static void find_annotations(void)
{
	struct rb_node *nd;

	for (nd = rb_first(&output_hists); nd; nd = rb_next(nd)) {
		struct hist_entry *he = rb_entry(nd, struct hist_entry, rb_node);
		struct sym_priv *priv;

		if (he->sym == NULL)
			continue;

		priv = symbol__priv(he->sym);
		if (priv->hist == NULL)
			continue;

		annotate_sym(he);
		/*
		 * Since we have a hist_entry per IP for the same symbol, free
		 * he->sym->hist to signal we already processed this symbol.
		 */
		free(priv->hist);
		priv->hist = NULL;
	}
}

static int __cmd_annotate(void)
{
	int ret, rc = EXIT_FAILURE;
	unsigned long offset = 0;
	unsigned long head = 0;
	struct stat input_stat;
	event_t *event;
	uint32_t size;
	char *buf;

	register_idle_thread();

	input = open(input_name, O_RDONLY);
	if (input < 0) {
		perror("failed to open file");
		exit(-1);
	}

	ret = fstat(input, &input_stat);
	if (ret < 0) {
		perror("failed to stat file");
		exit(-1);
	}

	if (!force && input_stat.st_uid && (input_stat.st_uid != geteuid())) {
		fprintf(stderr, "file: %s not owned by current user or root\n", input_name);
		exit(-1);
	}

	if (!input_stat.st_size) {
		fprintf(stderr, "zero-sized file, nothing to do!\n");
		exit(0);
	}

remap:
	buf = (char *)mmap(NULL, page_size * mmap_window, PROT_READ,
			   MAP_SHARED, input, offset);
	if (buf == MAP_FAILED) {
		perror("failed to mmap file");
		exit(-1);
	}

more:
	event = (event_t *)(buf + head);

	size = event->header.size;
	if (!size)
		size = 8;

	if (head + event->header.size >= page_size * mmap_window) {
		unsigned long shift = page_size * (head / page_size);
		int munmap_ret;

		munmap_ret = munmap(buf, page_size * mmap_window);
		assert(munmap_ret == 0);

		offset += shift;
		head -= shift;
		goto remap;
	}

	size = event->header.size;

	dump_printf("%p [%p]: event: %d\n",
			(void *)(offset + head),
			(void *)(long)event->header.size,
			event->header.type);

	if (!size || process_event(event, offset, head) < 0) {

		dump_printf("%p [%p]: skipping unknown header type: %d\n",
			(void *)(offset + head),
			(void *)(long)(event->header.size),
			event->header.type);

		total_unknown++;

		/*
		 * assume we lost track of the stream, check alignment, and
		 * increment a single u64 in the hope to catch on again 'soon'.
		 */

		if (unlikely(head & 7))
			head &= ~7ULL;

		size = 8;
	}

	head += size;

	if (offset + head < (unsigned long)input_stat.st_size)
		goto more;

	rc = EXIT_SUCCESS;
	close(input);

	dump_printf("      IP events: %10ld\n", total);
	dump_printf("    mmap events: %10ld\n", total_mmap);
	dump_printf("    comm events: %10ld\n", total_comm);
	dump_printf("    fork events: %10ld\n", total_fork);
	dump_printf(" unknown events: %10ld\n", total_unknown);

	if (dump_trace)
		return 0;

	if (verbose > 3)
		threads__fprintf(stdout);

	if (verbose > 2)
		dsos__fprintf(stdout);

	collapse__resort();
	output__resort(total);

	find_annotations();

	return rc;
}

static const char * const annotate_usage[] = {
	"perf annotate [<options>] <command>",
	NULL
};

static const struct option options[] = {
	OPT_STRING('i', "input", &input_name, "file",
		    "input file name"),
	OPT_STRING('s', "symbol", &sym_hist_filter, "symbol",
		    "symbol to annotate"),
	OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
	OPT_BOOLEAN('v', "verbose", &verbose,
		    "be more verbose (show symbol address, etc)"),
	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
		    "dump raw trace in ASCII"),
	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
		   "file", "vmlinux pathname"),
	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
		    "load module symbols - WARNING: use only with -k and LIVE kernel"),
	OPT_BOOLEAN('l', "print-line", &print_line,
		    "print matching source lines (may be slow)"),
	OPT_BOOLEAN('P', "full-paths", &full_paths,
		    "Don't shorten the displayed pathnames"),
	OPT_END()
};

static void setup_sorting(void)
{
	char *tmp, *tok, *str = strdup(sort_order);

	for (tok = strtok_r(str, ", ", &tmp);
			tok; tok = strtok_r(NULL, ", ", &tmp)) {
		if (sort_dimension__add(tok) < 0) {
			error("Unknown --sort key: `%s'", tok);
			usage_with_options(annotate_usage, options);
		}
	}

	free(str);
}

int cmd_annotate(int argc, const char **argv, const char *prefix __used)
{
	if (symbol__init(&symbol_conf) < 0)
		return -1;

	page_size = getpagesize();

	argc = parse_options(argc, argv, options, annotate_usage, 0);

	setup_sorting();

	if (argc) {
		/*
		 * Special case: if there's an argument left then assume tha
		 * it's a symbol filter:
		 */
		if (argc > 1)
			usage_with_options(annotate_usage, options);

		sym_hist_filter = argv[0];
	}

	setup_pager();

	if (field_sep && *field_sep == '.') {
		fputs("'.' is the only non valid --field-separator argument\n",
				stderr);
		exit(129);
	}

	return __cmd_annotate();
}
author	Marc Dionne <marc.c.dionne@gmail.com>	2009-04-23 06:21:55 -0400
committer	Linus Torvalds <torvalds@linux-foundation.org>	2009-04-24 16:28:30 -0400
commit	91ac033d8377552d3654501a105ab55bf546940e (patch)
tree	b3757b6b5f2180edb94049971850f76355abaa19 /Documentation/filesystems
parent	e5b89542ea18020961882228c26db3ba87f6e608 (diff)

diff --git a/Documentation/filesystems/caching/cachefiles.txt b/Documentation/filesystems/caching/cachefiles.txt index c78a49b7bba6..748a1ae49e12 100644 --- a/Documentation/filesystems/caching/cachefiles.txt +++ b/Documentation/filesystems/caching/cachefiles.txt
@@ -407,7 +407,7 @@ A NOTE ON SECURITY
407	==================	407	==================
408		408
409	CacheFiles makes use of the split security in the task_struct. It allocates	409	CacheFiles makes use of the split security in the task_struct. It allocates
410	its own task_security structure, and redirects current->act_as to point to it	410	its own task_security structure, and redirects current->cred to point to it
411	when it acts on behalf of another process, in that process's context.	411	when it acts on behalf of another process, in that process's context.
412		412
413	The reason it does this is that it calls vfs_mkdir() and suchlike rather than	413	The reason it does this is that it calls vfs_mkdir() and suchlike rather than
@@ -429,9 +429,9 @@ This means it may lose signals or ptrace events for example, and affects what
429	the process looks like in /proc.	429	the process looks like in /proc.
430		430
431	So CacheFiles makes use of a logical split in the security between the	431	So CacheFiles makes use of a logical split in the security between the
432	objective security (task->sec) and the subjective security (task->act_as). The	432	objective security (task->real_cred) and the subjective security (task->cred).
433	objective security holds the intrinsic security properties of a process and is	433	The objective security holds the intrinsic security properties of a process and
434	never overridden. This is what appears in /proc, and is what is used when a	434	is never overridden. This is what appears in /proc, and is what is used when a
435	process is the target of an operation by some other process (SIGKILL for	435	process is the target of an operation by some other process (SIGKILL for
436	example).	436	example).
437		437