probe-file.c 22.5 KB
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/*
 * probe-file.c : operate ftrace k/uprobe events files
 *
 * Written by Masami Hiramatsu <masami.hiramatsu.pt@hitachi.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.
 *
 */
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/stat.h>
#include <sys/types.h>
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#include <sys/uio.h>
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#include <unistd.h>
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#include "util.h"
#include "event.h"
#include "strlist.h"
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#include "strfilter.h"
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#include "debug.h"
#include "cache.h"
#include "color.h"
#include "symbol.h"
#include "thread.h"
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#include <api/fs/tracing_path.h>
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#include "probe-event.h"
#include "probe-file.h"
#include "session.h"
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#include "perf_regs.h"
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#include "string2.h"
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R
Ravi Bangoria 已提交
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/* 4096 - 2 ('\n' + '\0') */
#define MAX_CMDLEN 4094
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static void print_open_warning(int err, bool uprobe)
{
	char sbuf[STRERR_BUFSIZE];

	if (err == -ENOENT) {
		const char *config;

		if (uprobe)
			config = "CONFIG_UPROBE_EVENTS";
		else
			config = "CONFIG_KPROBE_EVENTS";

		pr_warning("%cprobe_events file does not exist"
			   " - please rebuild kernel with %s.\n",
			   uprobe ? 'u' : 'k', config);
	} else if (err == -ENOTSUP)
		pr_warning("Tracefs or debugfs is not mounted.\n");
	else
		pr_warning("Failed to open %cprobe_events: %s\n",
			   uprobe ? 'u' : 'k',
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			   str_error_r(-err, sbuf, sizeof(sbuf)));
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}

static void print_both_open_warning(int kerr, int uerr)
{
	/* Both kprobes and uprobes are disabled, warn it. */
	if (kerr == -ENOTSUP && uerr == -ENOTSUP)
		pr_warning("Tracefs or debugfs is not mounted.\n");
	else if (kerr == -ENOENT && uerr == -ENOENT)
		pr_warning("Please rebuild kernel with CONFIG_KPROBE_EVENTS "
			   "or/and CONFIG_UPROBE_EVENTS.\n");
	else {
		char sbuf[STRERR_BUFSIZE];
		pr_warning("Failed to open kprobe events: %s.\n",
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			   str_error_r(-kerr, sbuf, sizeof(sbuf)));
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		pr_warning("Failed to open uprobe events: %s.\n",
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			   str_error_r(-uerr, sbuf, sizeof(sbuf)));
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	}
}

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int open_trace_file(const char *trace_file, bool readwrite)
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{
	char buf[PATH_MAX];
	int ret;

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	ret = e_snprintf(buf, PATH_MAX, "%s/%s",
			 tracing_path, trace_file);
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	if (ret >= 0) {
		pr_debug("Opening %s write=%d\n", buf, readwrite);
		if (readwrite && !probe_event_dry_run)
			ret = open(buf, O_RDWR | O_APPEND, 0);
		else
			ret = open(buf, O_RDONLY, 0);

		if (ret < 0)
			ret = -errno;
	}
	return ret;
}

static int open_kprobe_events(bool readwrite)
{
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	return open_trace_file("kprobe_events", readwrite);
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}

static int open_uprobe_events(bool readwrite)
{
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	return open_trace_file("uprobe_events", readwrite);
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}

int probe_file__open(int flag)
{
	int fd;

	if (flag & PF_FL_UPROBE)
		fd = open_uprobe_events(flag & PF_FL_RW);
	else
		fd = open_kprobe_events(flag & PF_FL_RW);
	if (fd < 0)
		print_open_warning(fd, flag & PF_FL_UPROBE);

	return fd;
}

int probe_file__open_both(int *kfd, int *ufd, int flag)
{
	if (!kfd || !ufd)
		return -EINVAL;

	*kfd = open_kprobe_events(flag & PF_FL_RW);
	*ufd = open_uprobe_events(flag & PF_FL_RW);
	if (*kfd < 0 && *ufd < 0) {
		print_both_open_warning(*kfd, *ufd);
		return *kfd;
	}

	return 0;
}

/* Get raw string list of current kprobe_events  or uprobe_events */
struct strlist *probe_file__get_rawlist(int fd)
{
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	int ret, idx, fddup;
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	FILE *fp;
	char buf[MAX_CMDLEN];
	char *p;
	struct strlist *sl;

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	if (fd < 0)
		return NULL;

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	sl = strlist__new(NULL, NULL);
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	if (sl == NULL)
		return NULL;
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	fddup = dup(fd);
	if (fddup < 0)
		goto out_free_sl;

	fp = fdopen(fddup, "r");
	if (!fp)
		goto out_close_fddup;

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	while (!feof(fp)) {
		p = fgets(buf, MAX_CMDLEN, fp);
		if (!p)
			break;

		idx = strlen(p) - 1;
		if (p[idx] == '\n')
			p[idx] = '\0';
		ret = strlist__add(sl, buf);
		if (ret < 0) {
			pr_debug("strlist__add failed (%d)\n", ret);
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			goto out_close_fp;
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		}
	}
	fclose(fp);

	return sl;
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out_close_fp:
	fclose(fp);
	goto out_free_sl;
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out_close_fddup:
	close(fddup);
out_free_sl:
	strlist__delete(sl);
	return NULL;
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}

static struct strlist *__probe_file__get_namelist(int fd, bool include_group)
{
	char buf[128];
	struct strlist *sl, *rawlist;
	struct str_node *ent;
	struct probe_trace_event tev;
	int ret = 0;

	memset(&tev, 0, sizeof(tev));
	rawlist = probe_file__get_rawlist(fd);
	if (!rawlist)
		return NULL;
	sl = strlist__new(NULL, NULL);
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	strlist__for_each_entry(ent, rawlist) {
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		ret = parse_probe_trace_command(ent->s, &tev);
		if (ret < 0)
			break;
		if (include_group) {
			ret = e_snprintf(buf, 128, "%s:%s", tev.group,
					tev.event);
			if (ret >= 0)
				ret = strlist__add(sl, buf);
		} else
			ret = strlist__add(sl, tev.event);
		clear_probe_trace_event(&tev);
		if (ret < 0)
			break;
	}
	strlist__delete(rawlist);

	if (ret < 0) {
		strlist__delete(sl);
		return NULL;
	}
	return sl;
}

/* Get current perf-probe event names */
struct strlist *probe_file__get_namelist(int fd)
{
	return __probe_file__get_namelist(fd, false);
}

int probe_file__add_event(int fd, struct probe_trace_event *tev)
{
	int ret = 0;
	char *buf = synthesize_probe_trace_command(tev);
	char sbuf[STRERR_BUFSIZE];

	if (!buf) {
		pr_debug("Failed to synthesize probe trace event.\n");
		return -EINVAL;
	}

	pr_debug("Writing event: %s\n", buf);
	if (!probe_event_dry_run) {
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		if (write(fd, buf, strlen(buf)) < (int)strlen(buf)) {
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			ret = -errno;
			pr_warning("Failed to write event: %s\n",
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				   str_error_r(errno, sbuf, sizeof(sbuf)));
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		}
	}
	free(buf);

	return ret;
}

static int __del_trace_probe_event(int fd, struct str_node *ent)
{
	char *p;
	char buf[128];
	int ret;

	/* Convert from perf-probe event to trace-probe event */
	ret = e_snprintf(buf, 128, "-:%s", ent->s);
	if (ret < 0)
		goto error;

	p = strchr(buf + 2, ':');
	if (!p) {
		pr_debug("Internal error: %s should have ':' but not.\n",
			 ent->s);
		ret = -ENOTSUP;
		goto error;
	}
	*p = '/';

	pr_debug("Writing event: %s\n", buf);
	ret = write(fd, buf, strlen(buf));
	if (ret < 0) {
		ret = -errno;
		goto error;
	}

	return 0;
error:
	pr_warning("Failed to delete event: %s\n",
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		   str_error_r(-ret, buf, sizeof(buf)));
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	return ret;
}

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int probe_file__get_events(int fd, struct strfilter *filter,
			   struct strlist *plist)
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{
	struct strlist *namelist;
	struct str_node *ent;
	const char *p;
	int ret = -ENOENT;

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	if (!plist)
		return -EINVAL;

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	namelist = __probe_file__get_namelist(fd, true);
	if (!namelist)
		return -ENOENT;

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	strlist__for_each_entry(ent, namelist) {
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		p = strchr(ent->s, ':');
		if ((p && strfilter__compare(filter, p + 1)) ||
		    strfilter__compare(filter, ent->s)) {
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			strlist__add(plist, ent->s);
			ret = 0;
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		}
	}
	strlist__delete(namelist);

	return ret;
}
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int probe_file__del_strlist(int fd, struct strlist *namelist)
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{
	int ret = 0;
	struct str_node *ent;

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	strlist__for_each_entry(ent, namelist) {
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		ret = __del_trace_probe_event(fd, ent);
		if (ret < 0)
			break;
	}
	return ret;
}

int probe_file__del_events(int fd, struct strfilter *filter)
{
	struct strlist *namelist;
	int ret;

	namelist = strlist__new(NULL, NULL);
	if (!namelist)
		return -ENOMEM;

	ret = probe_file__get_events(fd, filter, namelist);
	if (ret < 0)
		return ret;

	ret = probe_file__del_strlist(fd, namelist);
	strlist__delete(namelist);

	return ret;
}
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/* Caller must ensure to remove this entry from list */
static void probe_cache_entry__delete(struct probe_cache_entry *entry)
{
	if (entry) {
		BUG_ON(!list_empty(&entry->node));

		strlist__delete(entry->tevlist);
		clear_perf_probe_event(&entry->pev);
		zfree(&entry->spev);
		free(entry);
	}
}

static struct probe_cache_entry *
probe_cache_entry__new(struct perf_probe_event *pev)
{
	struct probe_cache_entry *entry = zalloc(sizeof(*entry));

	if (entry) {
		INIT_LIST_HEAD(&entry->node);
		entry->tevlist = strlist__new(NULL, NULL);
		if (!entry->tevlist)
			zfree(&entry);
		else if (pev) {
			entry->spev = synthesize_perf_probe_command(pev);
			if (!entry->spev ||
			    perf_probe_event__copy(&entry->pev, pev) < 0) {
				probe_cache_entry__delete(entry);
				return NULL;
			}
		}
	}

	return entry;
}

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int probe_cache_entry__get_event(struct probe_cache_entry *entry,
				 struct probe_trace_event **tevs)
{
	struct probe_trace_event *tev;
	struct str_node *node;
	int ret, i;

	ret = strlist__nr_entries(entry->tevlist);
	if (ret > probe_conf.max_probes)
		return -E2BIG;

	*tevs = zalloc(ret * sizeof(*tev));
	if (!*tevs)
		return -ENOMEM;

	i = 0;
	strlist__for_each_entry(node, entry->tevlist) {
		tev = &(*tevs)[i++];
		ret = parse_probe_trace_command(node->s, tev);
		if (ret < 0)
			break;
	}
	return i;
}

/* For the kernel probe caches, pass target = NULL or DSO__NAME_KALLSYMS */
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static int probe_cache__open(struct probe_cache *pcache, const char *target,
			     struct nsinfo *nsi)
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{
	char cpath[PATH_MAX];
	char sbuildid[SBUILD_ID_SIZE];
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	char *dir_name = NULL;
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	bool is_kallsyms = false;
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	int ret, fd;
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	struct nscookie nsc;
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	if (target && build_id_cache__cached(target)) {
		/* This is a cached buildid */
		strncpy(sbuildid, target, SBUILD_ID_SIZE);
		dir_name = build_id_cache__linkname(sbuildid, NULL, 0);
		goto found;
	}

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	if (!target || !strcmp(target, DSO__NAME_KALLSYMS)) {
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		target = DSO__NAME_KALLSYMS;
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		is_kallsyms = true;
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		ret = sysfs__sprintf_build_id("/", sbuildid);
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	} else {
		nsinfo__mountns_enter(nsi, &nsc);
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		ret = filename__sprintf_build_id(target, sbuildid);
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		nsinfo__mountns_exit(&nsc);
	}
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	if (ret < 0) {
		pr_debug("Failed to get build-id from %s.\n", target);
		return ret;
	}

	/* If we have no buildid cache, make it */
	if (!build_id_cache__cached(sbuildid)) {
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		ret = build_id_cache__add_s(sbuildid, target, nsi,
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					    is_kallsyms, NULL);
		if (ret < 0) {
			pr_debug("Failed to add build-id cache: %s\n", target);
			return ret;
		}
	}

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	dir_name = build_id_cache__cachedir(sbuildid, target, nsi, is_kallsyms,
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					    false);
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found:
	if (!dir_name) {
		pr_debug("Failed to get cache from %s\n", target);
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		return -ENOMEM;
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	}
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	snprintf(cpath, PATH_MAX, "%s/probes", dir_name);
	fd = open(cpath, O_CREAT | O_RDWR, 0644);
	if (fd < 0)
		pr_debug("Failed to open cache(%d): %s\n", fd, cpath);
	free(dir_name);
	pcache->fd = fd;

	return fd;
}

static int probe_cache__load(struct probe_cache *pcache)
{
	struct probe_cache_entry *entry = NULL;
	char buf[MAX_CMDLEN], *p;
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	int ret = 0, fddup;
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	FILE *fp;

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	fddup = dup(pcache->fd);
	if (fddup < 0)
		return -errno;
	fp = fdopen(fddup, "r");
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	if (!fp) {
		close(fddup);
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		return -EINVAL;
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	}
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	while (!feof(fp)) {
		if (!fgets(buf, MAX_CMDLEN, fp))
			break;
		p = strchr(buf, '\n');
		if (p)
			*p = '\0';
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		/* #perf_probe_event or %sdt_event */
		if (buf[0] == '#' || buf[0] == '%') {
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			entry = probe_cache_entry__new(NULL);
			if (!entry) {
				ret = -ENOMEM;
				goto out;
			}
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			if (buf[0] == '%')
				entry->sdt = true;
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			entry->spev = strdup(buf + 1);
			if (entry->spev)
				ret = parse_perf_probe_command(buf + 1,
								&entry->pev);
			else
				ret = -ENOMEM;
			if (ret < 0) {
				probe_cache_entry__delete(entry);
				goto out;
			}
			list_add_tail(&entry->node, &pcache->entries);
		} else {	/* trace_probe_event */
			if (!entry) {
				ret = -EINVAL;
				goto out;
			}
			strlist__add(entry->tevlist, buf);
		}
	}
out:
	fclose(fp);
	return ret;
}

static struct probe_cache *probe_cache__alloc(void)
{
	struct probe_cache *pcache = zalloc(sizeof(*pcache));

	if (pcache) {
		INIT_LIST_HEAD(&pcache->entries);
		pcache->fd = -EINVAL;
	}
	return pcache;
}

void probe_cache__purge(struct probe_cache *pcache)
{
	struct probe_cache_entry *entry, *n;

	list_for_each_entry_safe(entry, n, &pcache->entries, node) {
		list_del_init(&entry->node);
		probe_cache_entry__delete(entry);
	}
}

void probe_cache__delete(struct probe_cache *pcache)
{
	if (!pcache)
		return;

	probe_cache__purge(pcache);
	if (pcache->fd > 0)
		close(pcache->fd);
	free(pcache);
}

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struct probe_cache *probe_cache__new(const char *target, struct nsinfo *nsi)
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{
	struct probe_cache *pcache = probe_cache__alloc();
	int ret;

	if (!pcache)
		return NULL;

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	ret = probe_cache__open(pcache, target, nsi);
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	if (ret < 0) {
		pr_debug("Cache open error: %d\n", ret);
		goto out_err;
	}

	ret = probe_cache__load(pcache);
	if (ret < 0) {
		pr_debug("Cache read error: %d\n", ret);
		goto out_err;
	}

	return pcache;

out_err:
	probe_cache__delete(pcache);
	return NULL;
}

static bool streql(const char *a, const char *b)
{
	if (a == b)
		return true;

	if (!a || !b)
		return false;

	return !strcmp(a, b);
}

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struct probe_cache_entry *
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probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
{
	struct probe_cache_entry *entry = NULL;
	char *cmd = synthesize_perf_probe_command(pev);

	if (!cmd)
		return NULL;

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	for_each_probe_cache_entry(entry, pcache) {
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		if (pev->sdt) {
			if (entry->pev.event &&
			    streql(entry->pev.event, pev->event) &&
			    (!pev->group ||
			     streql(entry->pev.group, pev->group)))
				goto found;

			continue;
		}
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		/* Hit if same event name or same command-string */
		if ((pev->event &&
		     (streql(entry->pev.group, pev->group) &&
		      streql(entry->pev.event, pev->event))) ||
		    (!strcmp(entry->spev, cmd)))
			goto found;
	}
	entry = NULL;

found:
	free(cmd);
	return entry;
}

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struct probe_cache_entry *
probe_cache__find_by_name(struct probe_cache *pcache,
			  const char *group, const char *event)
{
	struct probe_cache_entry *entry = NULL;

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	for_each_probe_cache_entry(entry, pcache) {
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		/* Hit if same event name or same command-string */
		if (streql(entry->pev.group, group) &&
		    streql(entry->pev.event, event))
			goto found;
	}
	entry = NULL;

found:
	return entry;
}

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int probe_cache__add_entry(struct probe_cache *pcache,
			   struct perf_probe_event *pev,
			   struct probe_trace_event *tevs, int ntevs)
{
	struct probe_cache_entry *entry = NULL;
	char *command;
	int i, ret = 0;

	if (!pcache || !pev || !tevs || ntevs <= 0) {
		ret = -EINVAL;
		goto out_err;
	}

	/* Remove old cache entry */
	entry = probe_cache__find(pcache, pev);
	if (entry) {
		list_del_init(&entry->node);
		probe_cache_entry__delete(entry);
	}

	ret = -ENOMEM;
	entry = probe_cache_entry__new(pev);
	if (!entry)
		goto out_err;

	for (i = 0; i < ntevs; i++) {
		if (!tevs[i].point.symbol)
			continue;

		command = synthesize_probe_trace_command(&tevs[i]);
		if (!command)
			goto out_err;
		strlist__add(entry->tevlist, command);
		free(command);
	}
	list_add_tail(&entry->node, &pcache->entries);
	pr_debug("Added probe cache: %d\n", ntevs);
	return 0;

out_err:
	pr_debug("Failed to add probe caches\n");
	probe_cache_entry__delete(entry);
	return ret;
}

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#ifdef HAVE_GELF_GETNOTE_SUPPORT
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static unsigned long long sdt_note__get_addr(struct sdt_note *note)
{
	return note->bit32 ? (unsigned long long)note->addr.a32[0]
		 : (unsigned long long)note->addr.a64[0];
}

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static const char * const type_to_suffix[] = {
	":s64", "", "", "", ":s32", "", ":s16", ":s8",
	"", ":u8", ":u16", "", ":u32", "", "", "", ":u64"
};

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/*
 * Isolate the string number and convert it into a decimal value;
 * this will be an index to get suffix of the uprobe name (defining
 * the type)
 */
static int sdt_arg_parse_size(char *n_ptr, const char **suffix)
{
	long type_idx;

	type_idx = strtol(n_ptr, NULL, 10);
	if (type_idx < -8 || type_idx > 8) {
		pr_debug4("Failed to get a valid sdt type\n");
		return -1;
	}

	*suffix = type_to_suffix[type_idx + 8];
	return 0;
}

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static int synthesize_sdt_probe_arg(struct strbuf *buf, int i, const char *arg)
{
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	char *op, *desc = strdup(arg), *new_op = NULL;
	const char *suffix = "";
732 733 734 735 736 737 738 739
	int ret = -1;

	if (desc == NULL) {
		pr_debug4("Allocation error\n");
		return ret;
	}

	/*
740 741 742
	 * Argument is in N@OP format. N is size of the argument and OP is
	 * the actual assembly operand. N can be omitted; in that case
	 * argument is just OP(without @).
743
	 */
744 745 746 747
	op = strchr(desc, '@');
	if (op) {
		op[0] = '\0';
		op++;
748

749 750 751 752
		if (sdt_arg_parse_size(desc, &suffix))
			goto error;
	} else {
		op = desc;
753 754
	}

755
	ret = arch_sdt_arg_parse_op(op, &new_op);
756

757 758
	if (ret < 0)
		goto error;
759

760 761
	if (ret == SDT_ARG_VALID) {
		ret = strbuf_addf(buf, " arg%d=%s%s", i + 1, new_op, suffix);
762 763 764 765 766 767 768
		if (ret < 0)
			goto error;
	}

	ret = 0;
error:
	free(desc);
769
	free(new_op);
770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807
	return ret;
}

static char *synthesize_sdt_probe_command(struct sdt_note *note,
					const char *pathname,
					const char *sdtgrp)
{
	struct strbuf buf;
	char *ret = NULL, **args;
	int i, args_count;

	if (strbuf_init(&buf, 32) < 0)
		return NULL;

	if (strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
				sdtgrp, note->name, pathname,
				sdt_note__get_addr(note)) < 0)
		goto error;

	if (!note->args)
		goto out;

	if (note->args) {
		args = argv_split(note->args, &args_count);

		for (i = 0; i < args_count; ++i) {
			if (synthesize_sdt_probe_arg(&buf, i, args[i]) < 0)
				goto error;
		}
	}

out:
	ret = strbuf_detach(&buf, NULL);
error:
	strbuf_release(&buf);
	return ret;
}

808 809 810 811 812 813 814 815 816 817 818 819
int probe_cache__scan_sdt(struct probe_cache *pcache, const char *pathname)
{
	struct probe_cache_entry *entry = NULL;
	struct list_head sdtlist;
	struct sdt_note *note;
	char *buf;
	char sdtgrp[64];
	int ret;

	INIT_LIST_HEAD(&sdtlist);
	ret = get_sdt_note_list(&sdtlist, pathname);
	if (ret < 0) {
820
		pr_debug4("Failed to get sdt note: %d\n", ret);
821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843
		return ret;
	}
	list_for_each_entry(note, &sdtlist, note_list) {
		ret = snprintf(sdtgrp, 64, "sdt_%s", note->provider);
		if (ret < 0)
			break;
		/* Try to find same-name entry */
		entry = probe_cache__find_by_name(pcache, sdtgrp, note->name);
		if (!entry) {
			entry = probe_cache_entry__new(NULL);
			if (!entry) {
				ret = -ENOMEM;
				break;
			}
			entry->sdt = true;
			ret = asprintf(&entry->spev, "%s:%s=%s", sdtgrp,
					note->name, note->name);
			if (ret < 0)
				break;
			entry->pev.event = strdup(note->name);
			entry->pev.group = strdup(sdtgrp);
			list_add_tail(&entry->node, &pcache->entries);
		}
844 845 846
		buf = synthesize_sdt_probe_command(note, pathname, sdtgrp);
		if (!buf) {
			ret = -ENOMEM;
847
			break;
848 849
		}

850 851 852 853 854 855 856 857 858 859 860
		strlist__add(entry->tevlist, buf);
		free(buf);
		entry = NULL;
	}
	if (entry) {
		list_del_init(&entry->node);
		probe_cache_entry__delete(entry);
	}
	cleanup_sdt_note_list(&sdtlist);
	return ret;
}
861
#endif
862

863 864 865 866 867
static int probe_cache_entry__write(struct probe_cache_entry *entry, int fd)
{
	struct str_node *snode;
	struct stat st;
	struct iovec iov[3];
868
	const char *prefix = entry->sdt ? "%" : "#";
869 870 871 872 873 874
	int ret;
	/* Save stat for rollback */
	ret = fstat(fd, &st);
	if (ret < 0)
		return ret;

875 876
	pr_debug("Writing cache: %s%s\n", prefix, entry->spev);
	iov[0].iov_base = (void *)prefix; iov[0].iov_len = 1;
877 878 879 880 881 882
	iov[1].iov_base = entry->spev; iov[1].iov_len = strlen(entry->spev);
	iov[2].iov_base = (void *)"\n"; iov[2].iov_len = 1;
	ret = writev(fd, iov, 3);
	if (ret < (int)iov[1].iov_len + 2)
		goto rollback;

883
	strlist__for_each_entry(snode, entry->tevlist) {
884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916
		iov[0].iov_base = (void *)snode->s;
		iov[0].iov_len = strlen(snode->s);
		iov[1].iov_base = (void *)"\n"; iov[1].iov_len = 1;
		ret = writev(fd, iov, 2);
		if (ret < (int)iov[0].iov_len + 1)
			goto rollback;
	}
	return 0;

rollback:
	/* Rollback to avoid cache file corruption */
	if (ret > 0)
		ret = -1;
	if (ftruncate(fd, st.st_size) < 0)
		ret = -2;

	return ret;
}

int probe_cache__commit(struct probe_cache *pcache)
{
	struct probe_cache_entry *entry;
	int ret = 0;

	/* TBD: if we do not update existing entries, skip it */
	ret = lseek(pcache->fd, 0, SEEK_SET);
	if (ret < 0)
		goto out;

	ret = ftruncate(pcache->fd, 0);
	if (ret < 0)
		goto out;

917
	for_each_probe_cache_entry(entry, pcache) {
918 919 920 921 922 923 924 925
		ret = probe_cache_entry__write(entry, pcache->fd);
		pr_debug("Cache committed: %d\n", ret);
		if (ret < 0)
			break;
	}
out:
	return ret;
}
926

927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953
static bool probe_cache_entry__compare(struct probe_cache_entry *entry,
				       struct strfilter *filter)
{
	char buf[128], *ptr = entry->spev;

	if (entry->pev.event) {
		snprintf(buf, 128, "%s:%s", entry->pev.group, entry->pev.event);
		ptr = buf;
	}
	return strfilter__compare(filter, ptr);
}

int probe_cache__filter_purge(struct probe_cache *pcache,
			      struct strfilter *filter)
{
	struct probe_cache_entry *entry, *tmp;

	list_for_each_entry_safe(entry, tmp, &pcache->entries, node) {
		if (probe_cache_entry__compare(entry, filter)) {
			pr_info("Removed cached event: %s\n", entry->spev);
			list_del_init(&entry->node);
			probe_cache_entry__delete(entry);
		}
	}
	return 0;
}

954 955 956 957 958
static int probe_cache__show_entries(struct probe_cache *pcache,
				     struct strfilter *filter)
{
	struct probe_cache_entry *entry;

959
	for_each_probe_cache_entry(entry, pcache) {
960
		if (probe_cache_entry__compare(entry, filter))
961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976
			printf("%s\n", entry->spev);
	}
	return 0;
}

/* Show all cached probes */
int probe_cache__show_all_caches(struct strfilter *filter)
{
	struct probe_cache *pcache;
	struct strlist *bidlist;
	struct str_node *nd;
	char *buf = strfilter__string(filter);

	pr_debug("list cache with filter: %s\n", buf);
	free(buf);

977
	bidlist = build_id_cache__list_all(true);
978 979 980 981 982
	if (!bidlist) {
		pr_debug("Failed to get buildids: %d\n", errno);
		return -EINVAL;
	}
	strlist__for_each_entry(nd, bidlist) {
983
		pcache = probe_cache__new(nd->s, NULL);
984 985 986 987 988 989 990 991 992 993 994 995 996 997
		if (!pcache)
			continue;
		if (!list_empty(&pcache->entries)) {
			buf = build_id_cache__origname(nd->s);
			printf("%s (%s):\n", buf, nd->s);
			free(buf);
			probe_cache__show_entries(pcache, filter);
		}
		probe_cache__delete(pcache);
	}
	strlist__delete(bidlist);

	return 0;
}
998

999 1000
enum ftrace_readme {
	FTRACE_README_PROBE_TYPE_X = 0,
1001
	FTRACE_README_KRETPROBE_OFFSET,
1002 1003 1004
	FTRACE_README_END,
};

1005 1006
static struct {
	const char *pattern;
1007 1008 1009 1010 1011
	bool avail;
} ftrace_readme_table[] = {
#define DEFINE_TYPE(idx, pat)			\
	[idx] = {.pattern = pat, .avail = false}
	DEFINE_TYPE(FTRACE_README_PROBE_TYPE_X, "*type: * x8/16/32/64,*"),
1012
	DEFINE_TYPE(FTRACE_README_KRETPROBE_OFFSET, "*place (kretprobe): *"),
1013 1014
};

1015
static bool scan_ftrace_readme(enum ftrace_readme type)
1016
{
1017
	int fd;
1018 1019 1020
	FILE *fp;
	char *buf = NULL;
	size_t len = 0;
1021 1022
	bool ret = false;
	static bool scanned = false;
1023

1024 1025
	if (scanned)
		goto result;
1026

1027 1028
	fd = open_trace_file("README", false);
	if (fd < 0)
1029 1030
		return ret;

1031 1032 1033 1034 1035
	fp = fdopen(fd, "r");
	if (!fp) {
		close(fd);
		return ret;
	}
1036

1037 1038 1039 1040 1041 1042
	while (getline(&buf, &len, fp) > 0)
		for (enum ftrace_readme i = 0; i < FTRACE_README_END; i++)
			if (!ftrace_readme_table[i].avail)
				ftrace_readme_table[i].avail =
					strglobmatch(buf, ftrace_readme_table[i].pattern);
	scanned = true;
1043 1044 1045 1046

	fclose(fp);
	free(buf);

1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061
result:
	if (type >= FTRACE_README_END)
		return false;

	return ftrace_readme_table[type].avail;
}

bool probe_type_is_available(enum probe_type type)
{
	if (type >= PROBE_TYPE_END)
		return false;
	else if (type == PROBE_TYPE_X)
		return scan_ftrace_readme(FTRACE_README_PROBE_TYPE_X);

	return true;
1062
}
1063 1064 1065 1066 1067

bool kretprobe_offset_is_supported(void)
{
	return scan_ftrace_readme(FTRACE_README_KRETPROBE_OFFSET);
}