[lttng-modules.git] / lttng-syscalls.c

/*
 * lttng-syscalls.c
 *
 * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * LTTng sched probes.
 *
 * Dual LGPL v2.1/GPL v2 license.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <asm/ptrace.h>
#include <asm/syscall.h>

#include "ltt-events.h"

static void syscall_entry_probe(void *__data, struct pt_regs *regs, long id);

/*
 * Take care of NOARGS not supported by mainline.
 */
#define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print)
#define DEFINE_EVENT_NOARGS(template, name)
#define TRACE_EVENT_NOARGS(name, struct, assign, print)

/*
 * Create LTTng tracepoint probes.
 */
#define LTTNG_PACKAGE_BUILD
#define CREATE_TRACE_POINTS

/* Hijack probe callback for system calls */
#define TP_PROBE_CB(_template)		&syscall_entry_probe
#define TP_MODULE_OVERRIDE

#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
#include "instrumentation/syscalls/headers/syscalls_integers.h"
#include "instrumentation/syscalls/headers/syscalls_pointers.h"
#include "instrumentation/syscalls/headers/syscalls_unknown.h"

#undef TP_MODULE_OVERRIDE
#undef TP_PROBE_CB
#undef LTTNG_PACKAGE_BUILD
#undef CREATE_TRACE_POINTS

struct trace_syscall_entry {
	void *func;
	const struct lttng_event_desc *desc;
	const struct lttng_event_field *fields;
	unsigned int nrargs;
};

#define CREATE_SYSCALL_TABLE

#undef TRACE_SYSCALL_TABLE
#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs)	\
	[ _nr ] = {						\
		.func = __event_probe__##_template,		\
		.nrargs = (_nrargs),				\
		.fields = __event_fields___##_template,		\
		.desc = &__event_desc___##_name,		\
	},

static struct trace_syscall_entry sc_table[] = {
#include "instrumentation/syscalls/headers/syscalls_integers.h"
#include "instrumentation/syscalls/headers/syscalls_pointers.h"
};

static int sc_table_filled;

#undef CREATE_SYSCALL_TABLE

static void syscall_entry_unknown(struct ltt_channel *chan,
	struct pt_regs *regs, unsigned int id)
{
	unsigned long args[UNKNOWN_SYSCALL_NRARGS];
	struct ltt_event *event;

	event = chan->sc_unknown;
	syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args);
	__event_probe__sys_unknown(event, id, args);
}

static void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
{
	struct trace_syscall_entry *entry;
	struct ltt_channel *chan = __data;
	struct ltt_event *event;

	if (unlikely(id >= ARRAY_SIZE(sc_table))) {
		syscall_entry_unknown(chan, regs, id);
		return;
	}
	event = chan->sc_table[id];
	if (unlikely(!event)) {
		syscall_entry_unknown(chan, regs, id);
		return;
	}
	entry = &sc_table[id];
	WARN_ON_ONCE(!entry);

	switch (entry->nrargs) {
	case 0:
	{
		void (*fptr)(void *__data) = entry->func;

		fptr(event);
		break;
	}
	case 1:
	{
		void (*fptr)(void *__data, unsigned long arg0) = entry->func;
		unsigned long args[1];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0]);
		break;
	}
	case 2:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1) = entry->func;
		unsigned long args[2];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1]);
		break;
	}
	case 3:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1,
			unsigned long arg2) = entry->func;
		unsigned long args[3];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1], args[2]);
		break;
	}
	case 4:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1,
			unsigned long arg2,
			unsigned long arg3) = entry->func;
		unsigned long args[4];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1], args[2], args[3]);
		break;
	}
	case 5:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1,
			unsigned long arg2,
			unsigned long arg3,
			unsigned long arg4) = entry->func;
		unsigned long args[5];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1], args[2], args[3], args[4]);
		break;
	}
	case 6:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1,
			unsigned long arg2,
			unsigned long arg3,
			unsigned long arg4,
			unsigned long arg5) = entry->func;
		unsigned long args[6];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1], args[2],
			args[3], args[4], args[5]);
		break;
	}
	default:
		break;
	}
}

int lttng_syscalls_register(struct ltt_channel *chan, void *filter)
{
	unsigned int i;
	int ret;

	wrapper_vmalloc_sync_all();

	if (!chan->sc_table) {
		/* create syscall table mapping syscall to events */
		chan->sc_table = kzalloc(sizeof(struct ltt_event *)
					* ARRAY_SIZE(sc_table), GFP_KERNEL);
		if (!chan->sc_table)
			return -ENOMEM;
	}

	if (!chan->sc_unknown) {
		struct lttng_kernel_event ev;

		const struct lttng_event_desc *desc =
			&__event_desc___sys_unknown;
		memset(&ev, 0, sizeof(ev));
		strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
		ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
		ev.instrumentation = LTTNG_KERNEL_NOOP;
		chan->sc_unknown = ltt_event_create(chan, &ev, filter,
						    desc);
		if (!chan->sc_unknown) {
			return -EINVAL;
		}
	}

	/* Allocate events for each syscall, insert into table */
	for (i = 0; i < ARRAY_SIZE(sc_table); i++) {
		struct lttng_kernel_event ev;
		const struct lttng_event_desc *desc = sc_table[i].desc;

		if (!desc) {
			/* Unknown syscall */
			continue;
		}
		/*
		 * Skip those already populated by previous failed
		 * register for this channel.
		 */
		if (chan->sc_table[i])
			continue;
		memset(&ev, 0, sizeof(ev));
		strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
		ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
		ev.instrumentation = LTTNG_KERNEL_NOOP;
		chan->sc_table[i] = ltt_event_create(chan, &ev, filter,
						     desc);
		if (!chan->sc_table[i]) {
			/*
			 * If something goes wrong in event registration
			 * after the first one, we have no choice but to
			 * leave the previous events in there, until
			 * deleted by session teardown.
			 */
			return -EINVAL;
		}
	}
	ret = tracepoint_probe_register("sys_enter",
			(void *) syscall_entry_probe, chan);
	if (ret)
		return ret;
	/*
	 * We change the name of sys_exit tracepoint due to namespace
	 * conflict with sys_exit syscall entry.
	 */
	ret = tracepoint_probe_register("sys_exit",
			(void *) __event_probe__exit_syscall, chan);
	if (ret) {
		WARN_ON_ONCE(tracepoint_probe_unregister("sys_enter",
			(void *) syscall_entry_probe, chan));
	}
	return ret;
}

/*
 * Only called at session destruction.
 */
int lttng_syscalls_unregister(struct ltt_channel *chan)
{
	int ret;

	if (!chan->sc_table)
		return 0;
	ret = tracepoint_probe_unregister("sys_exit",
			(void *) __event_probe__exit_syscall, chan);
	if (ret)
		return ret;
	ret = tracepoint_probe_unregister("sys_enter",
			(void *) syscall_entry_probe, chan);
	if (ret)
		return ret;
	/* ltt_event destroy will be performed by ltt_session_destroy() */
	kfree(chan->sc_table);
	return 0;
}
Commit	Line	Data
259b6cb3 MD	1	/*
	2	* lttng-syscalls.c
	3	*
	4	* Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*
	6	* LTTng sched probes.
	7	*
	8	* Dual LGPL v2.1/GPL v2 license.
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/slab.h>
	13	#include <asm/ptrace.h>
	14	#include <asm/syscall.h>
	15
	16	#include "ltt-events.h"
	17
	18	static void syscall_entry_probe(void __data, struct pt_regs regs, long id);
	19
f7bdf4db MD	20	/*
	21	* Take care of NOARGS not supported by mainline.
	22	*/
	23	#define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print)
	24	#define DEFINE_EVENT_NOARGS(template, name)
	25	#define TRACE_EVENT_NOARGS(name, struct, assign, print)
	26
259b6cb3 MD	27	/*
	28	* Create LTTng tracepoint probes.
	29	*/
	30	#define LTTNG_PACKAGE_BUILD
	31	#define CREATE_TRACE_POINTS
	32
	33	/* Hijack probe callback for system calls */
	34	#define TP_PROBE_CB(_template) &syscall_entry_probe
	35	#define TP_MODULE_OVERRIDE
	36
	37	#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
177b3692 MD	38	#include "instrumentation/syscalls/headers/syscalls_integers.h"
177b3692 MD	39	#include "instrumentation/syscalls/headers/syscalls_pointers.h"
63728b02	40	#include "instrumentation/syscalls/headers/syscalls_unknown.h"
259b6cb3 MD	41
	42	#undef TP_MODULE_OVERRIDE
	43	#undef TP_PROBE_CB
	44	#undef LTTNG_PACKAGE_BUILD
	45	#undef CREATE_TRACE_POINTS
	46
	47	struct trace_syscall_entry {
	48	void *func;
f7bdf4db	49	const struct lttng_event_desc *desc;
259b6cb3 MD	50	const struct lttng_event_field *fields;
	51	unsigned int nrargs;
	52	};
	53
259b6cb3 MD	54	#define CREATE_SYSCALL_TABLE
	55
	56	#undef TRACE_SYSCALL_TABLE
f7bdf4db	57	#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \
259b6cb3	58	[ _nr ] = { \
f7bdf4db	59	.func = __event_probe__##_template, \
259b6cb3	60	.nrargs = (_nrargs), \
f7bdf4db MD	61	.fields = __event_fields___##_template, \
f7bdf4db MD	62	.desc = &__event_desc___##_name, \
259b6cb3 MD	63	},
	64
	65	static struct trace_syscall_entry sc_table[] = {
177b3692 MD	66	#include "instrumentation/syscalls/headers/syscalls_integers.h"
177b3692 MD	67	#include "instrumentation/syscalls/headers/syscalls_pointers.h"
259b6cb3 MD	68	};
259b6cb3 MD	69
63728b02 MD	70	static int sc_table_filled;
63728b02 MD	71
259b6cb3 MD	72	#undef CREATE_SYSCALL_TABLE
259b6cb3 MD	73
f405cfce MD	74	static void syscall_entry_unknown(struct ltt_channel *chan,
	75	struct pt_regs *regs, unsigned int id)
	76	{
	77	unsigned long args[UNKNOWN_SYSCALL_NRARGS];
	78	struct ltt_event *event;
	79
	80	event = chan->sc_unknown;
	81	syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args);
	82	__event_probe__sys_unknown(event, id, args);
	83	}
	84
259b6cb3 MD	85	static void syscall_entry_probe(void __data, struct pt_regs regs, long id)
	86	{
	87	struct trace_syscall_entry *entry;
	88	struct ltt_channel *chan = __data;
	89	struct ltt_event *event;
	90
f405cfce MD	91	if (unlikely(id >= ARRAY_SIZE(sc_table))) {
f405cfce MD	92	syscall_entry_unknown(chan, regs, id);
259b6cb3	93	return;
f405cfce	94	}
259b6cb3	95	event = chan->sc_table[id];
f405cfce MD	96	if (unlikely(!event)) {
	97	syscall_entry_unknown(chan, regs, id);
	98	return;
	99	}
	100	entry = &sc_table[id];
	101	WARN_ON_ONCE(!entry);
259b6cb3 MD	102
	103	switch (entry->nrargs) {
	104	case 0:
	105	{
	106	void (fptr)(void __data) = entry->func;
	107
	108	fptr(event);
	109	break;
	110	}
	111	case 1:
	112	{
	113	void (fptr)(void __data, unsigned long arg0) = entry->func;
	114	unsigned long args[1];
	115
	116	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	117	fptr(event, args[0]);
	118	break;
	119	}
	120	case 2:
	121	{
	122	void (fptr)(void __data,
	123	unsigned long arg0,
	124	unsigned long arg1) = entry->func;
	125	unsigned long args[2];
	126
	127	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	128	fptr(event, args[0], args[1]);
	129	break;
	130	}
	131	case 3:
	132	{
	133	void (fptr)(void __data,
	134	unsigned long arg0,
	135	unsigned long arg1,
	136	unsigned long arg2) = entry->func;
	137	unsigned long args[3];
	138
	139	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	140	fptr(event, args[0], args[1], args[2]);
	141	break;
	142	}
	143	case 4:
	144	{
	145	void (fptr)(void __data,
	146	unsigned long arg0,
	147	unsigned long arg1,
	148	unsigned long arg2,
	149	unsigned long arg3) = entry->func;
	150	unsigned long args[4];
	151
	152	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	153	fptr(event, args[0], args[1], args[2], args[3]);
	154	break;
	155	}
	156	case 5:
	157	{
	158	void (fptr)(void __data,
	159	unsigned long arg0,
	160	unsigned long arg1,
	161	unsigned long arg2,
	162	unsigned long arg3,
	163	unsigned long arg4) = entry->func;
	164	unsigned long args[5];
	165
166	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
167	fptr(event, args[0], args[1], args[2], args[3], args[4]);
168	break;
169	}
170	case 6:
171	{
172	void (fptr)(void __data,
173	unsigned long arg0,
174	unsigned long arg1,
175	unsigned long arg2,
176	unsigned long arg3,
177	unsigned long arg4,
178	unsigned long arg5) = entry->func;
179	unsigned long args[6];
180
181	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
182	fptr(event, args[0], args[1], args[2],
183	args[3], args[4], args[5]);
184	break;
185	}
186	default:
187	break;
188	}
189	}
190
259b6cb3 MD	191	int lttng_syscalls_register(struct ltt_channel chan, void filter)
	192	{
	193	unsigned int i;
	194	int ret;
	195
	196	wrapper_vmalloc_sync_all();
259b6cb3 MD	197
	198	if (!chan->sc_table) {
	199	/* create syscall table mapping syscall to events */
	200	chan->sc_table = kzalloc(sizeof(struct ltt_event *)
	201	* ARRAY_SIZE(sc_table), GFP_KERNEL);
	202	if (!chan->sc_table)
	203	return -ENOMEM;
	204	}
	205
f405cfce MD	206	if (!chan->sc_unknown) {
	207	struct lttng_kernel_event ev;
	208
	209	const struct lttng_event_desc *desc =
	210	&__event_desc___sys_unknown;
	211	memset(&ev, 0, sizeof(ev));
	212	strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
	213	ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
	214	ev.instrumentation = LTTNG_KERNEL_NOOP;
	215	chan->sc_unknown = ltt_event_create(chan, &ev, filter,
	216	desc);
	217	if (!chan->sc_unknown) {
	218	return -EINVAL;
	219	}
	220	}
	221
259b6cb3 MD	222	/* Allocate events for each syscall, insert into table */
	223	for (i = 0; i < ARRAY_SIZE(sc_table); i++) {
	224	struct lttng_kernel_event ev;
	225	const struct lttng_event_desc *desc = sc_table[i].desc;
	226
f405cfce MD	227	if (!desc) {
	228	/* Unknown syscall */
	229	continue;
	230	}
259b6cb3 MD	231	/*
	232	* Skip those already populated by previous failed
	233	* register for this channel.
	234	*/
	235	if (chan->sc_table[i])
	236	continue;
	237	memset(&ev, 0, sizeof(ev));
	238	strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
	239	ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
	240	ev.instrumentation = LTTNG_KERNEL_NOOP;
	241	chan->sc_table[i] = ltt_event_create(chan, &ev, filter,
	242	desc);
	243	if (!chan->sc_table[i]) {
	244	/*
	245	* If something goes wrong in event registration
	246	* after the first one, we have no choice but to
	247	* leave the previous events in there, until
	248	* deleted by session teardown.
	249	*/
	250	return -EINVAL;
	251	}
	252	}
	253	ret = tracepoint_probe_register("sys_enter",
	254	(void *) syscall_entry_probe, chan);
63728b02 MD	255	if (ret)
	256	return ret;
	257	/*
	258	* We change the name of sys_exit tracepoint due to namespace
	259	* conflict with sys_exit syscall entry.
	260	*/
	261	ret = tracepoint_probe_register("sys_exit",
	262	(void *) __event_probe__exit_syscall, chan);
	263	if (ret) {
	264	WARN_ON_ONCE(tracepoint_probe_unregister("sys_enter",
	265	(void *) syscall_entry_probe, chan));
	266	}
259b6cb3 MD	267	return ret;
	268	}
	269
	270	/*
	271	* Only called at session destruction.
	272	*/
	273	int lttng_syscalls_unregister(struct ltt_channel *chan)
	274	{
	275	int ret;
	276
	277	if (!chan->sc_table)
	278	return 0;
63728b02 MD	279	ret = tracepoint_probe_unregister("sys_exit",
	280	(void *) __event_probe__exit_syscall, chan);
	281	if (ret)
	282	return ret;
259b6cb3 MD	283	ret = tracepoint_probe_unregister("sys_enter",
	284	(void *) syscall_entry_probe, chan);
	285	if (ret)
	286	return ret;
	287	/* ltt_event destroy will be performed by ltt_session_destroy() */
	288	kfree(chan->sc_table);
	289	return 0;
	290	}