[linux-2.6-block.git] / tools / perf / util / vdso.c


#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <linux/kernel.h>

#include "vdso.h"
#include "util.h"
#include "symbol.h"
#include "machine.h"
#include "linux/string.h"
#include "debug.h"

#define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX"

struct vdso_file {
	bool found;
	bool error;
	char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)];
	const char *dso_name;
};

struct vdso_info {
	struct vdso_file vdso;
};

static struct vdso_info *vdso_info__new(void)
{
	static const struct vdso_info vdso_info_init = {
		.vdso    = {
			.temp_file_name = VDSO__TEMP_FILE_NAME,
			.dso_name = DSO__NAME_VDSO,
		},
	};

	return memdup(&vdso_info_init, sizeof(vdso_info_init));
}

static int find_vdso_map(void **start, void **end)
{
	FILE *maps;
	char line[128];
	int found = 0;

	maps = fopen("/proc/self/maps", "r");
	if (!maps) {
		pr_err("vdso: cannot open maps\n");
		return -1;
	}

	while (!found && fgets(line, sizeof(line), maps)) {
		int m = -1;

		/* We care only about private r-x mappings. */
		if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n",
				start, end, &m))
			continue;
		if (m < 0)
			continue;

		if (!strncmp(&line[m], VDSO__MAP_NAME,
			     sizeof(VDSO__MAP_NAME) - 1))
			found = 1;
	}

	fclose(maps);
	return !found;
}

static char *get_file(struct vdso_file *vdso_file)
{
	char *vdso = NULL;
	char *buf = NULL;
	void *start, *end;
	size_t size;
	int fd;

	if (vdso_file->found)
		return vdso_file->temp_file_name;

	if (vdso_file->error || find_vdso_map(&start, &end))
		return NULL;

	size = end - start;

	buf = memdup(start, size);
	if (!buf)
		return NULL;

	fd = mkstemp(vdso_file->temp_file_name);
	if (fd < 0)
		goto out;

	if (size == (size_t) write(fd, buf, size))
		vdso = vdso_file->temp_file_name;

	close(fd);

 out:
	free(buf);

	vdso_file->found = (vdso != NULL);
	vdso_file->error = !vdso_file->found;
	return vdso;
}

void vdso__exit(struct machine *machine)
{
	struct vdso_info *vdso_info = machine->vdso_info;

	if (!vdso_info)
		return;

	if (vdso_info->vdso.found)
		unlink(vdso_info->vdso.temp_file_name);

	zfree(&machine->vdso_info);
}

static struct dso *vdso__new(struct machine *machine, const char *short_name,
			     const char *long_name)
{
	struct dso *dso;

	dso = dso__new(short_name);
	if (dso != NULL) {
		dsos__add(&machine->user_dsos, dso);
		dso__set_long_name(dso, long_name, false);
	}

	return dso;
}

struct dso *vdso__dso_findnew(struct machine *machine,
			      struct thread *thread __maybe_unused)
{
	struct vdso_info *vdso_info;
	struct dso *dso;

	if (!machine->vdso_info)
		machine->vdso_info = vdso_info__new();

	vdso_info = machine->vdso_info;
	if (!vdso_info)
		return NULL;

	dso = dsos__find(&machine->user_dsos, DSO__NAME_VDSO, true);
	if (!dso) {
		char *file;

		file = get_file(&vdso_info->vdso);
		if (!file)
			return NULL;

		dso = vdso__new(machine, DSO__NAME_VDSO, file);
	}

	return dso;
}

bool dso__is_vdso(struct dso *dso)
{
	return !strcmp(dso->short_name, DSO__NAME_VDSO);
}
Commit	Line	Data
7dbf4dcf JO	1
	2	#include <unistd.h>
	3	#include <stdio.h>
	4	#include <string.h>
	5	#include <sys/types.h>
	6	#include <sys/stat.h>
	7	#include <fcntl.h>
	8	#include <stdlib.h>
	9	#include <linux/kernel.h>
	10
	11	#include "vdso.h"
	12	#include "util.h"
	13	#include "symbol.h"
2a03068c	14	#include "machine.h"
7dbf4dcf	15	#include "linux/string.h"
84f5d36f	16	#include "debug.h"
7dbf4dcf	17
30f4f815 AH	18	#define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX"
	19
	20	struct vdso_file {
	21	bool found;
	22	bool error;
	23	char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)];
	24	const char *dso_name;
	25	};
	26
	27	struct vdso_info {
	28	struct vdso_file vdso;
	29	};
	30
d027b640 AH	31	static struct vdso_info *vdso_info__new(void)
	32	{
	33	static const struct vdso_info vdso_info_init = {
	34	.vdso = {
	35	.temp_file_name = VDSO__TEMP_FILE_NAME,
51682dc7	36	.dso_name = DSO__NAME_VDSO,
d027b640 AH	37	},
	38	};
	39
	40	return memdup(&vdso_info_init, sizeof(vdso_info_init));
	41	}
7dbf4dcf JO	42
	43	static int find_vdso_map(void start, void end)
	44	{
	45	FILE *maps;
	46	char line[128];
	47	int found = 0;
	48
	49	maps = fopen("/proc/self/maps", "r");
	50	if (!maps) {
	51	pr_err("vdso: cannot open maps\n");
	52	return -1;
	53	}
	54
	55	while (!found && fgets(line, sizeof(line), maps)) {
	56	int m = -1;
	57
	58	/* We care only about private r-x mappings. */
	59	if (2 != sscanf(line, "%p-%p r-xp %x %x:%x %u %n",
	60	start, end, &m))
	61	continue;
	62	if (m < 0)
	63	continue;
	64
	65	if (!strncmp(&line[m], VDSO__MAP_NAME,
	66	sizeof(VDSO__MAP_NAME) - 1))
	67	found = 1;
	68	}
	69
	70	fclose(maps);
	71	return !found;
	72	}
	73
30f4f815	74	static char get_file(struct vdso_file vdso_file)
7dbf4dcf JO	75	{
	76	char *vdso = NULL;
	77	char *buf = NULL;
	78	void start, end;
	79	size_t size;
	80	int fd;
	81
30f4f815 AH	82	if (vdso_file->found)
30f4f815 AH	83	return vdso_file->temp_file_name;
7dbf4dcf	84
30f4f815	85	if (vdso_file->error \|\| find_vdso_map(&start, &end))
7dbf4dcf JO	86	return NULL;
	87
	88	size = end - start;
	89
	90	buf = memdup(start, size);
	91	if (!buf)
	92	return NULL;
	93
30f4f815	94	fd = mkstemp(vdso_file->temp_file_name);
7dbf4dcf JO	95	if (fd < 0)
	96	goto out;
	97
	98	if (size == (size_t) write(fd, buf, size))
30f4f815	99	vdso = vdso_file->temp_file_name;
7dbf4dcf JO	100
	101	close(fd);
	102
	103	out:
	104	free(buf);
	105
30f4f815 AH	106	vdso_file->found = (vdso != NULL);
30f4f815 AH	107	vdso_file->error = !vdso_file->found;
7dbf4dcf JO	108	return vdso;
	109	}
	110
d027b640	111	void vdso__exit(struct machine *machine)
7dbf4dcf	112	{
d027b640 AH	113	struct vdso_info *vdso_info = machine->vdso_info;
	114
	115	if (!vdso_info)
	116	return;
	117
30f4f815 AH	118	if (vdso_info->vdso.found)
30f4f815 AH	119	unlink(vdso_info->vdso.temp_file_name);
d027b640 AH	120
d027b640 AH	121	zfree(&machine->vdso_info);
7dbf4dcf JO	122	}
7dbf4dcf JO	123
4f71f2a0 AH	124	static struct dso vdso__new(struct machine machine, const char *short_name,
	125	const char *long_name)
	126	{
	127	struct dso *dso;
	128
	129	dso = dso__new(short_name);
	130	if (dso != NULL) {
	131	dsos__add(&machine->user_dsos, dso);
	132	dso__set_long_name(dso, long_name, false);
	133	}
	134
	135	return dso;
	136	}
	137
5835edda AH	138	struct dso vdso__dso_findnew(struct machine machine,
5835edda AH	139	struct thread *thread __maybe_unused)
7dbf4dcf	140	{
d027b640 AH	141	struct vdso_info *vdso_info;
	142	struct dso *dso;
	143
	144	if (!machine->vdso_info)
	145	machine->vdso_info = vdso_info__new();
	146
	147	vdso_info = machine->vdso_info;
	148	if (!vdso_info)
	149	return NULL;
7dbf4dcf	150
51682dc7	151	dso = dsos__find(&machine->user_dsos, DSO__NAME_VDSO, true);
7dbf4dcf JO	152	if (!dso) {
	153	char *file;
	154
30f4f815	155	file = get_file(&vdso_info->vdso);
7dbf4dcf JO	156	if (!file)
	157	return NULL;
	158
51682dc7	159	dso = vdso__new(machine, DSO__NAME_VDSO, file);
7dbf4dcf JO	160	}
	161
	162	return dso;
	163	}
51682dc7 AH	164
	165	bool dso__is_vdso(struct dso *dso)
	166	{
	167	return !strcmp(dso->short_name, DSO__NAME_VDSO);
	168	}