Release 4.10 tools/perf/util/probe-event.c

/*
 * probe-event.c : perf-probe definition to probe_events format converter
 *
 * Written by Masami Hiramatsu <mhiramat@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <limits.h>
#include <elf.h>

#include "util.h"
#include "event.h"
#include "strlist.h"
#include "debug.h"
#include "cache.h"
#include "color.h"
#include "symbol.h"
#include "thread.h"
#include <api/fs/fs.h>
#include "trace-event.h"	/* For __maybe_unused */
#include "probe-event.h"
#include "probe-finder.h"
#include "probe-file.h"
#include "session.h"


#define MAX_CMDLEN 256

#define PERFPROBE_GROUP "probe"


bool probe_event_dry_run;	
/* Dry run flag */

struct probe_conf probe_conf;


#define semantic_error(msg ...) pr_err("Semantic error :" msg)



int e_snprintf(char *str, size_t size, const char *format, ...)
{
	int ret;
	va_list ap;
	va_start(ap, format);
	ret = vsnprintf(str, size, format, ap);
	va_end(ap);
	if (ret >= (int)size)
		ret = -E2BIG;
	return ret;
}

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masami hiramatsu
masami hiramatsu
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67
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static struct machine *host_machine;

/* Initialize symbol maps and path of vmlinux/modules */


int init_probe_symbol_maps(bool user_only)
{
	int ret;

	symbol_conf.sort_by_name = true;
	symbol_conf.allow_aliases = true;
	ret = symbol__init(NULL);
	if (ret < 0) {
		pr_debug("Failed to init symbol map.\n");
		goto out;
	}

	if (host_machine || user_only)	/* already initialized */
		return 0;

	if (symbol_conf.vmlinux_name)
		pr_debug("Use vmlinux: %s\n", symbol_conf.vmlinux_name);

	host_machine = machine__new_host();
	if (!host_machine) {
		pr_debug("machine__new_host() failed.\n");
		symbol__exit();
		ret = -1;
	}
out:
	if (ret < 0)
		pr_warning("Failed to init vmlinux path.\n");
	return ret;
}

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masami hiramatsu
masami hiramatsu
97
86.61%
4
44.44%
namhyung kim
namhyung kim
10
8.93%
3
33.33%
arnaldo carvalho de melo
arnaldo carvalho de melo
3
2.68%
1
11.11%
yanmin zhang
yanmin zhang
2
1.79%
1
11.11%
Total
112
100.00%
9
100.00%



void exit_probe_symbol_maps(void)
{
	machine__delete(host_machine);
	host_machine = NULL;
	symbol__exit();
}

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masami hiramatsu
masami hiramatsu
18
94.74%
1
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namhyung kim
namhyung kim
1
5.26%
1
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19
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2
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static struct symbol *__find_kernel_function_by_name(const char *name,
						     struct map **mapp)
{
	return machine__find_kernel_function_by_name(host_machine, name, mapp);
}

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masami hiramatsu
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static struct symbol *__find_kernel_function(u64 addr, struct map **mapp)
{
	return machine__find_kernel_function(host_machine, addr, mapp);
}

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masami hiramatsu
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static struct ref_reloc_sym *kernel_get_ref_reloc_sym(void)
{
	/* kmap->ref_reloc_sym should be set if host_machine is initialized */
	struct kmap *kmap;
	struct map *map = machine__kernel_map(host_machine);

	if (map__load(map) < 0)
		return NULL;

	kmap = map__kmap(map);
	if (!kmap)
		return NULL;
	return kmap->ref_reloc_sym;
}

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masami hiramatsu
masami hiramatsu
38
65.52%
1
33.33%
arnaldo carvalho de melo
arnaldo carvalho de melo
12
20.69%
1
33.33%
wang nan
wang nan
8
13.79%
1
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58
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3
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static int kernel_get_symbol_address_by_name(const char *name, u64 *addr,
					     bool reloc, bool reladdr)
{
	struct ref_reloc_sym *reloc_sym;
	struct symbol *sym;
	struct map *map;

	/* ref_reloc_sym is just a label. Need a special fix*/
	reloc_sym = kernel_get_ref_reloc_sym();
	if (reloc_sym && strcmp(name, reloc_sym->name) == 0)
		*addr = (reloc) ? reloc_sym->addr : reloc_sym->unrelocated_addr;
	else {
		sym = __find_kernel_function_by_name(name, &map);
		if (!sym)
			return -ENOENT;
		*addr = map->unmap_ip(map, sym->start) -
			((reloc) ? 0 : map->reloc) -
			((reladdr) ? map->start : 0);
	}
	return 0;
}

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masami hiramatsu
masami hiramatsu
133
98.52%
2
66.67%
he kuang
he kuang
2
1.48%
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135
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static struct map *kernel_get_module_map(const char *module)
{
	struct map_groups *grp = &host_machine->kmaps;
	struct maps *maps = &grp->maps[MAP__FUNCTION];
	struct map *pos;

	/* A file path -- this is an offline module */
	if (module && strchr(module, '/'))
		return dso__new_map(module);

	if (!module)
		module = "kernel";

	for (pos = maps__first(maps); pos; pos = map__next(pos)) {
		/* short_name is "[module]" */
		if (strncmp(pos->dso->short_name + 1, module,
			    pos->dso->short_name_len - 2) == 0 &&
		    module[pos->dso->short_name_len - 2] == '\0') {
			map__get(pos);
			return pos;
		}
	}
	return NULL;
}

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masami hiramatsu
masami hiramatsu
102
72.86%
5
62.50%
arnaldo carvalho de melo
arnaldo carvalho de melo
24
17.14%
2
25.00%
konstantin khlebnikov
konstantin khlebnikov
14
10.00%
1
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140
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8
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struct map *get_target_map(const char *target, bool user)
{
	/* Init maps of given executable or kernel */
	if (user)
		return dso__new_map(target);
	else
		return kernel_get_module_map(target);
}

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static int convert_exec_to_group(const char *exec, char **result)
{
	char *ptr1, *ptr2, *exec_copy;
	char buf[64];
	int ret;

	exec_copy = strdup(exec);
	if (!exec_copy)
		return -ENOMEM;

	ptr1 = basename(exec_copy);
	if (!ptr1) {
		ret = -EINVAL;
		goto out;
	}

	for (ptr2 = ptr1; *ptr2 != '\0'; ptr2++) {
		if (!isalnum(*ptr2) && *ptr2 != '_') {
			*ptr2 = '\0';
			break;
		}
	}

	ret = e_snprintf(buf, 64, "%s_%s", PERFPROBE_GROUP, ptr1);
	if (ret < 0)
		goto out;

	*result = strdup(buf);
	ret = *result ? 0 : -ENOMEM;

out:
	free(exec_copy);
	return ret;
}

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masami hiramatsu
masami hiramatsu
162
99.39%
3
75.00%
colin king
colin king
1
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1
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4
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static void clear_perf_probe_point(struct perf_probe_point *pp)
{
	free(pp->file);
	free(pp->function);
	free(pp->lazy_line);
}

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static void clear_probe_trace_events(struct probe_trace_event *tevs, int ntevs)
{
	int i;

	for (i = 0; i < ntevs; i++)
		clear_probe_trace_event(tevs + i);
}

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masami hiramatsu
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static bool kprobe_blacklist__listed(unsigned long address);


static bool kprobe_warn_out_range(const char *symbol, unsigned long address)
{
	u64 etext_addr = 0;
	int ret;

	/* Get the address of _etext for checking non-probable text symbol */
	ret = kernel_get_symbol_address_by_name("_etext", &etext_addr,
						false, false);

	if (ret == 0 && etext_addr < address)
		pr_warning("%s is out of .text, skip it.\n", symbol);
	else if (kprobe_blacklist__listed(address))
		pr_warning("%s is blacklisted function, skip it.\n", symbol);
	else
		return false;

	return true;
}

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masami hiramatsu
masami hiramatsu
67
87.01%
2
66.67%
he kuang
he kuang
10
12.99%
1
33.33%
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77
100.00%
3
100.00%

/*
 * @module can be module name of module file path. In case of path,
 * inspect elf and find out what is actual module name.
 * Caller has to free mod_name after using it.
 */


static char *find_module_name(const char *module)
{
	int fd;
	Elf *elf;
	GElf_Ehdr ehdr;
	GElf_Shdr shdr;
	Elf_Data *data;
	Elf_Scn *sec;
	char *mod_name = NULL;
	int name_offset;

	fd = open(module, O_RDONLY);
	if (fd < 0)
		return NULL;

	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
	if (elf == NULL)
		goto elf_err;

	if (gelf_getehdr(elf, &ehdr) == NULL)
		goto ret_err;

	sec = elf_section_by_name(elf, &ehdr, &shdr,
			".gnu.linkonce.this_module", NULL);
	if (!sec)
		goto ret_err;

	data = elf_getdata(sec, NULL);
	if (!data || !data->d_buf)
		goto ret_err;

	/*
         * NOTE:
         * '.gnu.linkonce.this_module' section of kernel module elf directly
         * maps to 'struct module' from linux/module.h. This section contains
         * actual module name which will be used by kernel after loading it.
         * But, we cannot use 'struct module' here since linux/module.h is not
         * exposed to user-space. Offset of 'name' has remained same from long
         * time, so hardcoding it here.
         */
	if (ehdr.e_ident[EI_CLASS] == ELFCLASS32)
		name_offset = 12;
	else	/* expect ELFCLASS64 by default */
		name_offset = 24;

	mod_name = strdup((char *)data->d_buf + name_offset);

ret_err:
	elf_end(elf);
elf_err:
	close(fd);
	return mod_name;
}

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ravi bangoria
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86.73%
1
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masami hiramatsu
masami hiramatsu
26
13.27%
1
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196
100.00%
2
100.00%

#ifdef HAVE_DWARF_SUPPORT



static int kernel_get_module_dso(const char *module, struct dso **pdso)
{
	struct dso *dso;
	struct map *map;
	const char *vmlinux_name;
	int ret = 0;

	if (module) {
		char module_name[128];

		snprintf(module_name, sizeof(module_name), "[%s]", module);
		map = map_groups__find_by_name(&host_machine->kmaps, MAP__FUNCTION, module_name);
		if (map) {
			dso = map->dso;
			goto found;
		}
		pr_debug("Failed to find module %s.\n", module);
		return -ENOENT;
	}

	map = machine__kernel_map(host_machine);
	dso = map->dso;

	vmlinux_name = symbol_conf.vmlinux_name;
	dso->load_errno = 0;
	if (vmlinux_name)
		ret = dso__load_vmlinux(dso, map, vmlinux_name, false);
	else
		ret = dso__load_vmlinux_path(dso, map);
found:
	*pdso = dso;
	return ret;
}

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wang nan
127
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1
33.33%
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arnaldo carvalho de melo
38
23.03%
2
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165
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/*
 * Some binaries like glibc have special symbols which are on the symbol
 * table, but not in the debuginfo. If we can find the address of the
 * symbol from map, we can translate the address back to the probe point.
 */


static int find_alternative_probe_point(struct debuginfo *dinfo,
					struct perf_probe_point *pp,
					struct perf_probe_point *result,
					const char *target, bool uprobes)
{
	struct map *map = NULL;
	struct symbol *sym;
	u64 address = 0;
	int ret = -ENOENT;

	/* This can work only for function-name based one */
	if (!pp->function || pp->file)
		return -ENOTSUP;

	map = get_target_map(target, uprobes);
	if (!map)
		return -EINVAL;

	/* Find the address of given function */
	map__for_each_symbol_by_name(map, pp->function, sym) {
		if (uprobes)
			address = sym->start;
		else
			address = map->unmap_ip(map, sym->start) - map->reloc;
		break;
	}
	if (!address) {
		ret = -ENOENT;
		goto out;
	}
	pr_debug("Symbol %s address found : %" PRIx64 "\n",
			pp->function, address);

	ret = debuginfo__find_probe_point(dinfo, (unsigned long)address,
					  result);
	if (ret <= 0)
		ret = (!ret) ? -ENOENT : ret;
	else {
		result->offset += pp->offset;
		result->line += pp->line;
		result->retprobe = pp->retprobe;
		ret = 0;
	}

out:
	map__put(map);
	return ret;

}

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masami hiramatsu
masami hiramatsu
217
95.18%
4
66.67%
he kuang
he kuang
8
3.51%
1
16.67%
wang nan
wang nan
3
1.32%
1
16.67%
Total
228
100.00%
6
100.00%



static int get_alternative_probe_event(struct debuginfo *dinfo,
				       struct perf_probe_event *pev,
				       struct perf_probe_point *tmp)
{
	int ret;

	memcpy(tmp, &pev->point, sizeof(*tmp));
	memset(&pev->point, 0, sizeof(pev->point));
	ret = find_alternative_probe_point(dinfo, tmp, &pev->point,
					   pev->target, pev->uprobes);
	if (ret < 0)
		memcpy(&pev->point, tmp, sizeof(*tmp));

	return ret;
}

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masami hiramatsu
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104
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4
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static int get_alternative_line_range(struct debuginfo *dinfo,
				      struct line_range *lr,
				      const char *target, bool user)
{
	struct perf_probe_point pp = { .function = lr->function,
				       .file = lr->file,
				       .line = lr->start };
	struct perf_probe_point result;
	int ret, len = 0;

	memset(&result, 0, sizeof(result));

	if (lr->end != INT_MAX)
		len = lr->end - lr->start;
	ret = find_alternative_probe_point(dinfo, &pp, &result,
					   target, user);
	if (!ret) {
		lr->function = result.function;
		lr->file = result.file;
		lr->start = result.line;
		if (lr->end != INT_MAX)
			lr->end = lr->start + len;
		clear_perf_probe_point(&pp);
	}
	return ret;
}

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masami hiramatsu
masami hiramatsu
141
83.93%
1
50.00%
david ahern
david ahern
27
16.07%
1
50.00%
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168
100.00%
2
100.00%

/* Open new debuginfo of given module */


static struct debuginfo *open_debuginfo(const char *module, bool silent)
{
	const char *path = module;
	char reason[STRERR_BUFSIZE];
	struct debuginfo *ret = NULL;
	struct dso *dso = NULL;
	int err;

	if (!module || !strchr(module, '/')) {
		err = kernel_get_module_dso(module, &dso);
		if (err < 0) {
			if (!dso || dso->load_errno == 0) {
				if (!str_error_r(-err, reason, STRERR_BUFSIZE))
					strcpy(reason, "(unknown)");
			} else
				dso__strerror_load(dso, reason, STRERR_BUFSIZE);
			if (!silent)
				pr_err("Failed to find the path for %s: %s\n",
					module ?: "kernel", reason);
			return NULL;
		}
		path = dso->long_name;
	}
	ret = debuginfo__new(path);
	if (!ret && !silent) {
		pr_warning("The %s file has no debug information.\n", path);
		if (!module || !strtailcmp(path, ".ko"))
			pr_warning("Rebuild with CONFIG_DEBUG_INFO=y, ");
		else
			pr_warning("Rebuild with -g, ");
		pr_warning("or install an appropriate debuginfo package.\n");
	}
	return ret;
}

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masami hiramatsu
masami hiramatsu
203
99.51%
7
87.50%
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arnaldo carvalho de melo
1
0.49%
1
12.50%
Total
204
100.00%
8
100.00%

/* For caching the last debuginfo */

static struct debuginfo *debuginfo_cache;

static char *debuginfo_cache_path;



static struct debuginfo *debuginfo_cache__open(const char *module, bool silent)
{
	const char *path = module;

	/* If the module is NULL, it should be the kernel. */
	if (!module)
		path = "kernel";

	if (debuginfo_cache_path && !strcmp(debuginfo_cache_path, path))
		goto out;

	/* Copy module path */
	free(debuginfo_cache_path);
	debuginfo_cache_path = strdup(path);
	if (!debuginfo_cache_path) {
		debuginfo__delete(debuginfo_cache);
		debuginfo_cache = NULL;
		goto out;
	}

	debuginfo_cache = open_debuginfo(module, silent);
	if (!debuginfo_cache)
		zfree(&debuginfo_cache_path);
out:
	return debuginfo_cache;
}

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masami hiramatsu
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105
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static void debuginfo_cache__exit(void)
{
	debuginfo__delete(debuginfo_cache);
	debuginfo_cache = NULL;
	zfree(&debuginfo_cache_path);
}


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23
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static int get_text_start_address(const char *exec, unsigned long *address)
{
	Elf *elf;
	GElf_Ehdr ehdr;
	GElf_Shdr shdr;
	int fd, ret = -ENOENT;

	fd = open(exec, O_RDONLY);
	if (fd < 0)
		return -errno;

	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
	if (elf == NULL) {
		ret = -EINVAL;
		goto out_close;
	}

	if (gelf_getehdr(elf, &ehdr) == NULL)
		goto out;

	if (!elf_section_by_name(elf, &ehdr, &shdr, ".text", NULL))
		goto out;

	*address = shdr.sh_addr - shdr.sh_offset;
	ret = 0;
out:
	elf_end(elf);
out_close:
	close(fd);

	return ret;
}

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masami hiramatsu
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148
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10
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/*
 * Convert trace point to probe point with debuginfo
 */


static int find_perf_probe_point_from_dwarf(struct probe_trace_point *tp,
					    struct perf_probe_point *pp,
					    bool is_kprobe)
{
	struct debuginfo *dinfo = NULL;
	unsigned long stext = 0;
	u64 addr = tp->address;
	int ret = -ENOENT;

	/* convert the address to dwarf address */
	if (!is_kprobe) {
		if (!addr) {
			ret = -EINVAL;
			goto error;
		}
		ret = get_text_start_address(tp->module, &stext);
		if (ret < 0)
			goto error;
		addr += stext;
	} else if (tp->symbol) {
		/* If the module is given, this returns relative address */
		ret = kernel_get_symbol_address_by_name(tp->symbol, &addr,
							false, !!tp->module);
		if (ret != 0)
			goto error;
		addr += tp->offset;
	}

	pr_debug("try to find information at %" PRIx64 " in %s\n", addr,
		 tp->module ? : "kernel");

	dinfo = debuginfo_cache__open(tp->module, verbose == 0);
	if (dinfo)
		ret = debuginfo__find_probe_point(dinfo,
						 (unsigned long)addr, pp);
	else
		ret = -ENOENT;

	if (ret > 0) {
		pp->retprobe = tp->retprobe;
		return 0;
	}
error:
	pr_debug("Failed to find corresponding probes from debuginfo.\n");
	return ret ? : -ENOENT;
}

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masami hiramatsu
masami hiramatsu
218
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wang nan
wang nan
7
3.11%
1
16.67%
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225
100.00%
6
100.00%

/* Adjust symbol name and address */


static int post_process_probe_trace_point(struct probe_trace_point *tp,
					   struct map *map, unsigned long offs)
{
	struct symbol *sym;
	u64 addr = tp->address + tp->offset - offs;

	sym = map__find_symbol(map, addr);
	if (!sym)
		return -ENOENT;

	if (strcmp(sym->name, tp->symbol)) {
		/* If we have no realname, use symbol for it */
		if (!tp->realname)
			tp->realname = tp->symbol;
		else
			free(tp->symbol);
		tp->symbol = strdup(sym->name);
		if (!tp->symbol)
			return -ENOMEM;
	}
	tp->offset = addr - sym->start;
	tp->address -= offs;

	return 0;
}

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masami hiramatsu
masami hiramatsu
136
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1
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Total
136
100.00%
1
100.00%

/*
 * Rename DWARF symbols to ELF symbols -- gcc sometimes optimizes functions
 * and generate new symbols with suffixes such as .constprop.N or .isra.N
 * etc. Since those symbols are not recorded in DWARF, we have to find
 * correct generated symbols from offline ELF binary.
 * For online kernel or uprobes we don't need this because those are
 * rebased on _text, or already a section relative address.
 */

static int

post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
					int ntevs, const char *pathname)
{
	struct map *map;
	unsigned long stext = 0;
	int i, ret = 0;

	/* Prepare a map for offline binary */
	map = dso__new_map(pathname);
	if (