[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 <linux/compat.h>
#include <asm/ptrace.h>
#include <asm/syscall.h>

#include "ltt-events.h"

#ifndef CONFIG_COMPAT
static inline int is_compat_task(void)
{
	return 0;
}
#endif

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
#define TP_MODULE_OVERRIDE
#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers

/* Hijack probe callback for system calls */
#define TP_PROBE_CB(_template)		&syscall_entry_probe
#include "instrumentation/syscalls/headers/syscalls_integers.h"
#include "instrumentation/syscalls/headers/syscalls_pointers.h"
#undef TP_PROBE_CB

#include "instrumentation/syscalls/headers/syscalls_unknown.h"

#undef TP_MODULE_OVERRIDE
#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"
};

#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);
}

/*
 * Currently, given that the kernel syscall metadata extraction only
 * considers native system calls (not 32-bit compability ones), we
 * fall-back on the "unknown" system call tracing for 32-bit compat.
 */
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(is_compat_task() || 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;
		}
	}

	if (!chan->sc_exit) {
		struct lttng_kernel_event ev;
		const struct lttng_event_desc *desc =
			&__event_desc___exit_syscall;

		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_exit = ltt_event_create(chan, &ev, filter,
						 desc);
		if (!chan->sc_exit) {
			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->sc_exit);
	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->sc_exit);
	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>
6333ace3	13	#include <linux/compat.h>
259b6cb3 MD	14	#include <asm/ptrace.h>
	15	#include <asm/syscall.h>
	16
	17	#include "ltt-events.h"
	18
6333ace3 MD	19	#ifndef CONFIG_COMPAT
	20	static inline int is_compat_task(void)
	21	{
	22	return 0;
	23	}
	24	#endif
	25
259b6cb3 MD	26	static void syscall_entry_probe(void __data, struct pt_regs regs, long id);
259b6cb3 MD	27
f7bdf4db MD	28	/*
	29	* Take care of NOARGS not supported by mainline.
	30	*/
	31	#define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print)
	32	#define DEFINE_EVENT_NOARGS(template, name)
	33	#define TRACE_EVENT_NOARGS(name, struct, assign, print)
	34
259b6cb3 MD	35	/*
	36	* Create LTTng tracepoint probes.
	37	*/
	38	#define LTTNG_PACKAGE_BUILD
	39	#define CREATE_TRACE_POINTS
2f804c0a MD	40	#define TP_MODULE_OVERRIDE
2f804c0a MD	41	#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
259b6cb3 MD	42
	43	/* Hijack probe callback for system calls */
	44	#define TP_PROBE_CB(_template) &syscall_entry_probe
177b3692 MD	45	#include "instrumentation/syscalls/headers/syscalls_integers.h"
177b3692 MD	46	#include "instrumentation/syscalls/headers/syscalls_pointers.h"
2f804c0a MD	47	#undef TP_PROBE_CB
2f804c0a MD	48
63728b02	49	#include "instrumentation/syscalls/headers/syscalls_unknown.h"
259b6cb3 MD	50
259b6cb3 MD	51	#undef TP_MODULE_OVERRIDE
259b6cb3 MD	52	#undef LTTNG_PACKAGE_BUILD
	53	#undef CREATE_TRACE_POINTS
	54
	55	struct trace_syscall_entry {
	56	void *func;
f7bdf4db	57	const struct lttng_event_desc *desc;
259b6cb3 MD	58	const struct lttng_event_field *fields;
	59	unsigned int nrargs;
	60	};
	61
259b6cb3 MD	62	#define CREATE_SYSCALL_TABLE
	63
	64	#undef TRACE_SYSCALL_TABLE
f7bdf4db	65	#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \
259b6cb3	66	[ _nr ] = { \
f7bdf4db	67	.func = __event_probe__##_template, \
259b6cb3	68	.nrargs = (_nrargs), \
f7bdf4db MD	69	.fields = __event_fields___##_template, \
f7bdf4db MD	70	.desc = &__event_desc___##_name, \
259b6cb3 MD	71	},
	72
	73	static struct trace_syscall_entry sc_table[] = {
177b3692 MD	74	#include "instrumentation/syscalls/headers/syscalls_integers.h"
177b3692 MD	75	#include "instrumentation/syscalls/headers/syscalls_pointers.h"
259b6cb3 MD	76	};
	77
	78	#undef CREATE_SYSCALL_TABLE
	79
f405cfce MD	80	static void syscall_entry_unknown(struct ltt_channel *chan,
	81	struct pt_regs *regs, unsigned int id)
	82	{
	83	unsigned long args[UNKNOWN_SYSCALL_NRARGS];
	84	struct ltt_event *event;
	85
	86	event = chan->sc_unknown;
	87	syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args);
	88	__event_probe__sys_unknown(event, id, args);
	89	}
	90
6333ace3 MD	91	/*
	92	* Currently, given that the kernel syscall metadata extraction only
	93	* considers native system calls (not 32-bit compability ones), we
	94	* fall-back on the "unknown" system call tracing for 32-bit compat.
	95	*/
259b6cb3 MD	96	static void syscall_entry_probe(void __data, struct pt_regs regs, long id)
	97	{
	98	struct trace_syscall_entry *entry;
	99	struct ltt_channel *chan = __data;
	100	struct ltt_event *event;
	101
6333ace3	102	if (unlikely(is_compat_task() \|\| id >= ARRAY_SIZE(sc_table))) {
f405cfce	103	syscall_entry_unknown(chan, regs, id);
259b6cb3	104	return;
f405cfce	105	}
259b6cb3	106	event = chan->sc_table[id];
f405cfce MD	107	if (unlikely(!event)) {
	108	syscall_entry_unknown(chan, regs, id);
	109	return;
	110	}
	111	entry = &sc_table[id];
	112	WARN_ON_ONCE(!entry);
259b6cb3 MD	113
	114	switch (entry->nrargs) {
	115	case 0:
	116	{
	117	void (fptr)(void __data) = entry->func;
	118
	119	fptr(event);
	120	break;
	121	}
	122	case 1:
	123	{
	124	void (fptr)(void __data, unsigned long arg0) = entry->func;
	125	unsigned long args[1];
	126
	127	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	128	fptr(event, args[0]);
	129	break;
	130	}
	131	case 2:
	132	{
	133	void (fptr)(void __data,
	134	unsigned long arg0,
	135	unsigned long arg1) = entry->func;
	136	unsigned long args[2];
	137
	138	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	139	fptr(event, args[0], args[1]);
	140	break;
	141	}
	142	case 3:
	143	{
	144	void (fptr)(void __data,
	145	unsigned long arg0,
	146	unsigned long arg1,
	147	unsigned long arg2) = entry->func;
	148	unsigned long args[3];
	149
	150	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	151	fptr(event, args[0], args[1], args[2]);
	152	break;
	153	}
	154	case 4:
	155	{
	156	void (fptr)(void __data,
	157	unsigned long arg0,
	158	unsigned long arg1,
	159	unsigned long arg2,
	160	unsigned long arg3) = entry->func;
	161	unsigned long args[4];
	162
	163	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	164	fptr(event, args[0], args[1], args[2], args[3]);
	165	break;
	166	}
	167	case 5:
	168	{
	169	void (fptr)(void __data,
	170	unsigned long arg0,
	171	unsigned long arg1,
	172	unsigned long arg2,
	173	unsigned long arg3,
	174	unsigned long arg4) = entry->func;
	175	unsigned long args[5];
	176
177	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
178	fptr(event, args[0], args[1], args[2], args[3], args[4]);
179	break;
180	}
181	case 6:
182	{
183	void (fptr)(void __data,
184	unsigned long arg0,
185	unsigned long arg1,
186	unsigned long arg2,
187	unsigned long arg3,
188	unsigned long arg4,
189	unsigned long arg5) = entry->func;
190	unsigned long args[6];
191
192	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
193	fptr(event, args[0], args[1], args[2],
194	args[3], args[4], args[5]);
195	break;
196	}
197	default:
198	break;
199	}
200	}
201
259b6cb3 MD	202	int lttng_syscalls_register(struct ltt_channel chan, void filter)
	203	{
	204	unsigned int i;
	205	int ret;
	206
	207	wrapper_vmalloc_sync_all();
259b6cb3 MD	208
	209	if (!chan->sc_table) {
	210	/* create syscall table mapping syscall to events */
	211	chan->sc_table = kzalloc(sizeof(struct ltt_event *)
	212	* ARRAY_SIZE(sc_table), GFP_KERNEL);
	213	if (!chan->sc_table)
	214	return -ENOMEM;
	215	}
	216
f405cfce MD	217	if (!chan->sc_unknown) {
f405cfce MD	218	struct lttng_kernel_event ev;
f405cfce MD	219	const struct lttng_event_desc *desc =
f405cfce MD	220	&__event_desc___sys_unknown;
2f804c0a	221
f405cfce MD	222	memset(&ev, 0, sizeof(ev));
	223	strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
	224	ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
	225	ev.instrumentation = LTTNG_KERNEL_NOOP;
	226	chan->sc_unknown = ltt_event_create(chan, &ev, filter,
	227	desc);
	228	if (!chan->sc_unknown) {
	229	return -EINVAL;
	230	}
	231	}
	232
2f804c0a MD	233	if (!chan->sc_exit) {
	234	struct lttng_kernel_event ev;
	235	const struct lttng_event_desc *desc =
	236	&__event_desc___exit_syscall;
	237
	238	memset(&ev, 0, sizeof(ev));
	239	strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
	240	ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
	241	ev.instrumentation = LTTNG_KERNEL_NOOP;
	242	chan->sc_exit = ltt_event_create(chan, &ev, filter,
	243	desc);
	244	if (!chan->sc_exit) {
	245	return -EINVAL;
	246	}
	247	}
	248
259b6cb3 MD	249	/* Allocate events for each syscall, insert into table */
	250	for (i = 0; i < ARRAY_SIZE(sc_table); i++) {
	251	struct lttng_kernel_event ev;
	252	const struct lttng_event_desc *desc = sc_table[i].desc;
	253
f405cfce MD	254	if (!desc) {
	255	/* Unknown syscall */
	256	continue;
	257	}
259b6cb3 MD	258	/*
	259	* Skip those already populated by previous failed
	260	* register for this channel.
	261	*/
	262	if (chan->sc_table[i])
	263	continue;
	264	memset(&ev, 0, sizeof(ev));
	265	strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
	266	ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
	267	ev.instrumentation = LTTNG_KERNEL_NOOP;
	268	chan->sc_table[i] = ltt_event_create(chan, &ev, filter,
	269	desc);
	270	if (!chan->sc_table[i]) {
	271	/*
	272	* If something goes wrong in event registration
	273	* after the first one, we have no choice but to
	274	* leave the previous events in there, until
	275	* deleted by session teardown.
	276	*/
	277	return -EINVAL;
	278	}
	279	}
	280	ret = tracepoint_probe_register("sys_enter",
	281	(void *) syscall_entry_probe, chan);
63728b02 MD	282	if (ret)
	283	return ret;
	284	/*
	285	* We change the name of sys_exit tracepoint due to namespace
	286	* conflict with sys_exit syscall entry.
	287	*/
	288	ret = tracepoint_probe_register("sys_exit",
2c01ec07	289	(void *) __event_probe__exit_syscall,
2f804c0a	290	chan->sc_exit);
63728b02 MD	291	if (ret) {
	292	WARN_ON_ONCE(tracepoint_probe_unregister("sys_enter",
	293	(void *) syscall_entry_probe, chan));
	294	}
259b6cb3 MD	295	return ret;
	296	}
	297
	298	/*
	299	* Only called at session destruction.
	300	*/
	301	int lttng_syscalls_unregister(struct ltt_channel *chan)
	302	{
	303	int ret;
	304
	305	if (!chan->sc_table)
	306	return 0;
63728b02	307	ret = tracepoint_probe_unregister("sys_exit",
2c01ec07	308	(void *) __event_probe__exit_syscall,
2f804c0a	309	chan->sc_exit);
63728b02 MD	310	if (ret)
63728b02 MD	311	return ret;
259b6cb3 MD	312	ret = tracepoint_probe_unregister("sys_enter",
	313	(void *) syscall_entry_probe, chan);
	314	if (ret)
	315	return ret;
	316	/* ltt_event destroy will be performed by ltt_session_destroy() */
	317	kfree(chan->sc_table);
	318	return 0;
	319	}