path: root/trace-util.c

/*
 * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License (not later!)
 *
 * 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser 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
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <ctype.h>
#include <errno.h>
#include <dlfcn.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "trace-cmd.h"

#define LOCAL_PLUGIN_DIR ".trace-cmd/plugins"
#define DEBUGFS_PATH "/sys/kernel/debug"

int tracecmd_disable_sys_plugins;
int tracecmd_disable_plugins;

#define _STR(x) #x
#define STR(x) _STR(x)

#ifndef MAX_PATH
# define MAX_PATH 1024
#endif

struct plugin_list {
	struct plugin_list	*next;
	char			*name;
	void			*handle;
};

void parse_cmdlines(struct pevent *pevent,
		    char *file, int size __unused)
{
	char *comm;
	char *line;
	char *next = NULL;
	int pid;

	line = strtok_r(file, "\n", &next);
	while (line) {
		sscanf(line, "%d %as", &pid,
		       (float *)(void *)&comm); /* workaround gcc warning */
		pevent_register_comm(pevent, comm, pid);
		free(comm);
		line = strtok_r(NULL, "\n", &next);
	}
}

void parse_proc_kallsyms(struct pevent *pevent,
			 char *file, unsigned int size __unused)
{
	unsigned long long addr;
	char *func;
	char *line;
	char *next = NULL;
	char *addr_str;
	char *mod;
	char ch;
	int ret;

	line = strtok_r(file, "\n", &next);
	while (line) {
		mod = NULL;
		ret = sscanf(line, "%as %c %as\t[%as",
			     (float *)(void *)&addr_str, /* workaround gcc warning */
			     &ch,
			     (float *)(void *)&func,
			     (float *)(void *)&mod);
		addr = strtoull(addr_str, NULL, 16);
		free(addr_str);

		/* truncate the extra ']' */
		if (mod)
			mod[strlen(mod) - 1] = 0;

		pevent_register_function(pevent, func, addr, mod);
		free(func);
		free(mod);

		line = strtok_r(NULL, "\n", &next);
	}
}

void parse_ftrace_printk(struct pevent *pevent,
			 char *file, unsigned int size __unused)
{
	unsigned long long addr;
	char *printk;
	char *line;
	char *next = NULL;
	char *addr_str;
	char *fmt;

	line = strtok_r(file, "\n", &next);
	while (line) {
		addr_str = strtok_r(line, ":", &fmt);
		if (!addr_str) {
			warning("printk format with empty entry");
			break;
		}
		addr = strtoull(addr_str, NULL, 16);
		/* fmt still has a space, skip it */
		printk = strdup(fmt+1);
		line = strtok_r(NULL, "\n", &next);
		pevent_register_print_string(pevent, printk, addr);
	}
}

static void load_plugin(struct pevent *pevent, const char *path,
			const char *file, void *data)
{
	struct plugin_list **plugin_list = data;
	pevent_plugin_load_func func;
	struct plugin_list *list;
	char *plugin;
	void *handle;

	plugin = malloc_or_die(strlen(path) + strlen(file) + 2);

	strcpy(plugin, path);
	strcat(plugin, "/");
	strcat(plugin, file);

	handle = dlopen(plugin, RTLD_NOW | RTLD_GLOBAL);
	if (!handle) {
		warning("cound not load plugin '%s'\n%s\n",
			plugin, dlerror());
		goto out_free;
	}

	func = dlsym(handle, PEVENT_PLUGIN_LOADER_NAME);
	if (!func) {
		warning("cound not find func '%s' in plugin '%s'\n%s\n",
			PEVENT_PLUGIN_LOADER_NAME, plugin, dlerror());
		goto out_free;
	}

	list = malloc_or_die(sizeof(*list));
	list->next = *plugin_list;
	list->handle = handle;
	list->name = plugin;
	*plugin_list = list;

	pr_stat("registering plugin: %s", plugin);
	func(pevent);
	return;

 out_free:
	free(plugin);
}

static int mount_debugfs(void)
{
	struct stat st;
	int ret;

	/* make sure debugfs exists */
	ret = stat(DEBUGFS_PATH, &st);
	if (ret < 0)
		die("debugfs is not configured on this kernel");

	ret = mount("nodev", DEBUGFS_PATH,
		    "debugfs", 0, NULL);

	return ret;
}

char *tracecmd_find_tracing_dir(void)
{
	char debugfs[MAX_PATH+1];
	char *tracing_dir;
	char type[100];
	FILE *fp;
	
	if ((fp = fopen("/proc/mounts","r")) == NULL) {
		warning("Can't open /proc/mounts for read");
		return NULL;
	}

	while (fscanf(fp, "%*s %"
		      STR(MAX_PATH)
		      "s %99s %*s %*d %*d\n",
		      debugfs, type) == 2) {
		if (strcmp(type, "debugfs") == 0)
			break;
	}
	fclose(fp);

	if (strcmp(type, "debugfs") != 0) {
		/* If debugfs is not mounted, try to mount it */
		if (mount_debugfs() < 0) {
			warning("debugfs not mounted, please mount");
			return NULL;
		}
		strcpy(debugfs, DEBUGFS_PATH);
	}

	tracing_dir = malloc_or_die(strlen(debugfs) + 9);
	if (!tracing_dir)
		return NULL;

	sprintf(tracing_dir, "%s/tracing", debugfs);

	return tracing_dir;
}

static char *append_file(const char *dir, const char *name)
{
	char *file;

	file = malloc_or_die(strlen(dir) + strlen(name) + 2);
	if (!file)
		return NULL;

	sprintf(file, "%s/%s", dir, name);
	return file;
}

char **tracecmd_add_list(char **list, const char *name, int len)
{
	if (!list)
		list = malloc_or_die(sizeof(*list) * 2);
	else {
		list = realloc(list, sizeof(*list) * (len + 2));
		if (!list)
			die("Can not allocate list");
	}

	list[len] = strdup(name);
	if (!list[len])
		die("Can not allocate list");

	list[len + 1] = NULL;

	return list;
}

void tracecmd_free_list(char **list)
{
	int i;

	if (!list)
		return;

	for (i = 0; list[i]; i++)
		free(list[i]);

	free(list);
}

/**
 * tracecmd_event_systems - return list of systems for tracing
 * @tracing_dir: directory holding the "events" directory
 *
 * Returns an allocated list of system names. Both the names and
 * the list must be freed with free().
 * The list returned ends with a "NULL" pointer.
 */
char **tracecmd_event_systems(const char *tracing_dir)
{
	struct dirent *dent;
	char **systems = NULL;
	char *events_dir;
	struct stat st;
	DIR *dir;
	int len = 0;
	int ret;

	if (!tracing_dir)
		return NULL;

	events_dir = append_file(tracing_dir, "events");
	if (!events_dir)
		return NULL;

	/*
	 * Search all the directories in the events directory,
 	 * and collect the ones that have the "enable" file.
	 */
	ret = stat(events_dir, &st);
	if (ret < 0 || !S_ISDIR(st.st_mode))
		goto out_free;

	dir = opendir(events_dir);
	if (!dir)
		goto out_free;

	while ((dent = readdir(dir))) {
		const char *name = dent->d_name;
		char *enable;
		char *sys;

		if (strcmp(name, ".") == 0 ||
		    strcmp(name, "..") == 0)
			continue;

		sys = append_file(events_dir, name);
		ret = stat(sys, &st);
		if (ret < 0 || !S_ISDIR(st.st_mode)) {
			free(sys);
			continue;
		}

		enable = append_file(sys, "enable");

		ret = stat(enable, &st);
		if (ret >= 0)
			systems = tracecmd_add_list(systems, name, len++);

		free(enable);
		free(sys);
	}

	closedir(dir);

 out_free:
	free(events_dir);
	return systems;
}

/**
 * tracecmd_system_events - return list of events for system
 * @tracing_dir: directory holding the "events" directory
 * @system: the system to return the events for
 *
 * Returns an allocated list of event names. Both the names and
 * the list must be freed with free().
 * The list returned ends with a "NULL" pointer.
 */
char **tracecmd_system_events(const char *tracing_dir, const char *system)
{
	struct dirent *dent;
	char **events = NULL;
	char *events_dir;
	char *system_dir;
	struct stat st;
	DIR *dir;
	int len = 0;
	int ret;

	if (!tracing_dir || !system)
		return NULL;

	events_dir = append_file(tracing_dir, "events");
	if (!events_dir)
		return NULL;

	/*
	 * Search all the directories in the systems directory,
	 * and collect the ones that have the "enable" file.
	 */
	ret = stat(events_dir, &st);
	if (ret < 0 || !S_ISDIR(st.st_mode))
		goto out_free;

	system_dir = append_file(events_dir, system);
	if (!system_dir)
		goto out_free;

	ret = stat(system_dir, &st);
	if (ret < 0 || !S_ISDIR(st.st_mode))
		goto out_free_sys;

	dir = opendir(system_dir);
	if (!dir)
		goto out_free_sys;

	while ((dent = readdir(dir))) {
		const char *name = dent->d_name;
		char *enable;
		char *event;

		if (strcmp(name, ".") == 0 ||
		    strcmp(name, "..") == 0)
			continue;

		event = append_file(system_dir, name);
		ret = stat(event, &st);
		if (ret < 0 || !S_ISDIR(st.st_mode)) {
			free(event);
			continue;
		}

		enable = append_file(event, "enable");

		ret = stat(enable, &st);
		if (ret >= 0)
			events = tracecmd_add_list(events, name, len++);

		free(enable);
		free(event);
	}

	closedir(dir);

 out_free_sys:
	free(system_dir);

 out_free:
	free(events_dir);

	return events;
}

static int read_file(const char *file, char **buffer)
{
	char *buf;
	int len = 0;
	int fd;
	int r;

	fd = open(file, O_RDONLY);
	if (fd < 0)
		return -1;

	buf = malloc_or_die(BUFSIZ + 1);

	while ((r = read(fd, buf + len, BUFSIZ)) > 0) {
		len += r;
		buf = realloc(buf, len + BUFSIZ + 1);
		if (!buf) {
			len = -1;
			goto out;
		}
	}

	*buffer = buf;
	buf[len] = 0;
 out:
	close(fd);

	return len;
}

static void load_events(struct pevent *pevent, const char *system,
			const char *sys_dir)
{
	struct dirent *dent;
	struct stat st;
	DIR *dir;
	int len = 0;
	int ret;

	ret = stat(sys_dir, &st);
	if (ret < 0 || !S_ISDIR(st.st_mode))
		return;

	dir = opendir(sys_dir);
	if (!dir)
		return;

	while ((dent = readdir(dir))) {
		const char *name = dent->d_name;
		char *event;
		char *format;
		char *buf;

		if (strcmp(name, ".") == 0 ||
		    strcmp(name, "..") == 0)
			continue;

		event = append_file(sys_dir, name);
		ret = stat(event, &st);
		if (ret < 0 || !S_ISDIR(st.st_mode))
			goto free_event;

		format = append_file(event, "format");
		ret = stat(format, &st);
		if (ret < 0)
			goto free_format;

		len = read_file(format, &buf);
		if (len < 0)
			goto free_format;

		pevent_parse_event(pevent, buf, len, system);
		free(buf);
 free_format:
		free(format);
 free_event:
		free(event);
	}

	closedir(dir);
}

static int read_header(struct pevent *pevent, const char *events_dir)
{
	struct stat st;
	char *header;
	char *buf;
	int len;
	int ret = -1;

	header = append_file(events_dir, "header_page");

	ret = stat(header, &st);
	if (ret < 0)
		goto out;

	len = read_file(header, &buf);
	if (len < 0)
		goto out;

	pevent_parse_header_page(pevent, buf, len, sizeof(long));

	free(buf);

	ret = 0;
 out:
	free(header);
	return ret;
}

/**
 * tracecmd_local_events - create a pevent from the events on system
 * @tracing_dir: The directory that contains the events.
 *
 * Returns a pevent structure that contains the pevents local to
 * the system.
 */
struct pevent *tracecmd_local_events(const char *tracing_dir)
{
	struct pevent *pevent = NULL;
	struct dirent *dent;
	char *events_dir;
	struct stat st;
	DIR *dir;
	int ret;

	if (!tracing_dir)
		return NULL;

	events_dir = append_file(tracing_dir, "events");
	if (!events_dir)
		return NULL;

	ret = stat(events_dir, &st);
	if (ret < 0 || !S_ISDIR(st.st_mode))
		goto out_free;

	dir = opendir(events_dir);
	if (!dir)
		goto out_free;

	pevent = pevent_alloc();
	if (!pevent)
		goto out_free;

	ret = read_header(pevent, events_dir);
	if (ret < 0) {
		pevent_free(pevent);
		pevent = NULL;
		goto out_free;
	}

	while ((dent = readdir(dir))) {
		const char *name = dent->d_name;
		char *sys;

		if (strcmp(name, ".") == 0 ||
		    strcmp(name, "..") == 0)
			continue;

		sys = append_file(events_dir, name);
		ret = stat(sys, &st);
		if (ret < 0 || !S_ISDIR(st.st_mode)) {
			free(sys);
			continue;
		}

		load_events(pevent, name, sys);

		free(sys);
	}

	closedir(dir);

 out_free:
	free(events_dir);

	return pevent;
}

/**
 * tracecmd_local_plugins - returns an array of available tracer plugins
 * @tracing_dir: The directory that contains the tracing directory
 *
 * Returns an allocate list of plugins. The array ends with NULL.
 * Both the plugin names and array must be freed with free().
 */
char **tracecmd_local_plugins(const char *tracing_dir)
{
	char *available_tracers;
	struct stat st;
	char **plugins = NULL;
	char *buf;
	char *str, *saveptr;
	char *plugin;
	int slen;
	int len;
	int ret;

	if (!tracing_dir)
		return NULL;

	available_tracers = append_file(tracing_dir, "available_tracers");
	if (!available_tracers)
		return NULL;

	ret = stat(available_tracers, &st);
	if (ret < 0)
		goto out_free;

	len = read_file(available_tracers, &buf);
	if (len < 0)
		goto out_free;

	len = 0;
	for (str = buf; ; str = NULL) {
		plugin = strtok_r(str, " ", &saveptr);
		if (!plugin)
			break;
		if (!(slen = strlen(plugin)))
			continue;

		/* chop off any newlines */
		if (plugin[slen - 1] == '\n')
			plugin[slen - 1] = '\0';

		/* Skip the non tracers */
		if (strcmp(plugin, "nop") == 0 ||
		    strcmp(plugin, "none") == 0)
			continue;

		plugins = tracecmd_add_list(plugins, plugin, len++);
	}
	free(buf);

 out_free:
	free(available_tracers);

	return plugins;
}

static void
trace_util_load_plugins_dir(struct pevent *pevent, const char *suffix,
			    const char *path,
			    void (*load_plugin)(struct pevent *pevent,
						const char *path,
						const char *name,
						void *data),
			    void *data)
{
	struct dirent *dent;
	struct stat st;
	DIR *dir;
	int ret;

	ret = stat(path, &st);
	if (ret < 0)
		return;

	if (!S_ISDIR(st.st_mode))
		return;

	dir = opendir(path);
	if (!dir)
		return;

	while ((dent = readdir(dir))) {
		const char *name = dent->d_name;

		if (strcmp(name, ".") == 0 ||
		    strcmp(name, "..") == 0)
			continue;

		/* Only load plugins that end in suffix */
		if (strcmp(name + (strlen(name) - strlen(suffix)), suffix) != 0)
			continue;

		load_plugin(pevent, path, name, data);
	}

	closedir(dir);

	return;
}

void trace_util_load_plugins(struct pevent *pevent, const char *suffix,
			     void (*load_plugin)(struct pevent *pevent,
						 const char *path,
						 const char *name,
						 void *data),
			     void *data)
{
	char *home;
	char *path;

	if (tracecmd_disable_plugins)
		return;

/* If a system plugin directory was defined, check that first */
#ifdef PLUGIN_DIR
	if (!tracecmd_disable_sys_plugins)
		trace_util_load_plugins_dir(pevent, suffix, PLUGIN_DIR,
					    load_plugin, data);
#endif

	/* Now let the home directory override the system defaults */
	home = getenv("HOME");

	if (!home)
		return;

	path = malloc_or_die(strlen(home) + strlen(LOCAL_PLUGIN_DIR) + 2);

	strcpy(path, home);
	strcat(path, "/");
	strcat(path, LOCAL_PLUGIN_DIR);

	trace_util_load_plugins_dir(pevent, suffix, path, load_plugin, data);

	free(path);
}

struct plugin_list *tracecmd_load_plugins(struct pevent *pevent)
{
	struct plugin_list *list = NULL;

	trace_util_load_plugins(pevent, ".so", load_plugin, &list);

	return list;
}

void tracecmd_unload_plugins(struct plugin_list *plugin_list)
{
	pevent_plugin_unload_func func;
	struct plugin_list *list;

	while (plugin_list) {
		list = plugin_list;
		plugin_list = list->next;
		func = dlsym(list->handle, PEVENT_PLUGIN_UNLOADER_NAME);
		if (func)
			func();
		dlclose(list->handle);
		free(list->name);
		free(list);
	}
}