aboutsummaryrefslogtreecommitdiff
path: root/sys/cddl/dev/systrace/systrace.c
blob: 90274223c51221854a30b524444c0c799fcc8530 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 * Portions Copyright 2006-2008 John Birrell jb@freebsd.org
 */

/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/cpuvar.h>
#include <sys/dtrace.h>
#include <sys/fcntl.h>
#include <sys/filio.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/kthread.h>
#include <sys/limits.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/selinfo.h>
#include <sys/smp.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/uio.h>
#include <sys/unistd.h>

#include <cddl/dev/dtrace/dtrace_cddl.h>

#include <machine/stdarg.h>

#ifdef LINUX_SYSTRACE
#if defined(__amd64__)
#include <amd64/linux/linux.h>
#include <amd64/linux/linux_proto.h>
#include <amd64/linux/linux_syscalls.c>
#include <amd64/linux/linux_systrace_args.c>
#elif defined(__i386__)
#include <i386/linux/linux.h>
#include <i386/linux/linux_proto.h>
#include <i386/linux/linux_syscalls.c>
#include <i386/linux/linux_systrace_args.c>
#else
#error Only i386 and amd64 are supported.
#endif
#define	MODNAME		"linux"
extern struct sysent linux_sysent[];
#define	MAXSYSCALL	LINUX_SYS_MAXSYSCALL
#define	SYSCALLNAMES	linux_syscallnames
#define	SYSENT		linux_sysent
#elif defined(LINUX32_SYSTRACE)
#if defined(__amd64__)
#include <amd64/linux32/linux.h>
#include <amd64/linux32/linux32_proto.h>
#include <amd64/linux32/linux32_syscalls.c>
#include <amd64/linux32/linux32_systrace_args.c>
#else
#error Only amd64 is supported.
#endif
#define	MODNAME		"linux32"
extern struct sysent linux32_sysent[];
#define	MAXSYSCALL	LINUX32_SYS_MAXSYSCALL
#define	SYSCALLNAMES	linux32_syscallnames
#define	SYSENT		linux32_sysent
#elif defined(FREEBSD32_SYSTRACE)
/*
 * The syscall arguments are processed into a DTrace argument array
 * using a generated function. See sys/kern/makesyscalls.sh.
 */
#include <compat/freebsd32/freebsd32_proto.h>
#include <compat/freebsd32/freebsd32_util.h>
#include <compat/freebsd32/freebsd32_syscall.h>
#include <compat/freebsd32/freebsd32_systrace_args.c>
extern const char *freebsd32_syscallnames[];
#define	MODNAME		"freebsd32"
#define	MAXSYSCALL	FREEBSD32_SYS_MAXSYSCALL
#define	SYSCALLNAMES	freebsd32_syscallnames
#define	SYSENT		freebsd32_sysent
#else
/*
 * The syscall arguments are processed into a DTrace argument array
 * using a generated function. See sys/kern/makesyscalls.sh.
 */
#include <sys/syscall.h>
#include <kern/systrace_args.c>
#define	MODNAME		"freebsd"
#define	MAXSYSCALL	SYS_MAXSYSCALL
#define	SYSCALLNAMES	syscallnames
#define	SYSENT		sysent
#define	NATIVE_ABI
#endif

#define	PROVNAME	"syscall"
#define	DEVNAME	        "dtrace/systrace/" MODNAME

#define	SYSTRACE_ARTIFICIAL_FRAMES	1

#define	SYSTRACE_SHIFT			16
#define	SYSTRACE_ISENTRY(x)		((int)(x) >> SYSTRACE_SHIFT)
#define	SYSTRACE_SYSNUM(x)		((int)(x) & ((1 << SYSTRACE_SHIFT) - 1))
#define	SYSTRACE_ENTRY(id)		((1 << SYSTRACE_SHIFT) | (id))
#define	SYSTRACE_RETURN(id)		(id)

#if ((1 << SYSTRACE_SHIFT) <= MAXSYSCALL)
#error 1 << SYSTRACE_SHIFT must exceed number of system calls
#endif

static int systrace_enabled_count;

static void	systrace_load(void *);
static void	systrace_unload(void *);

static void	systrace_getargdesc(void *, dtrace_id_t, void *,
		    dtrace_argdesc_t *);
static uint64_t	systrace_getargval(void *, dtrace_id_t, void *, int, int);
static void	systrace_provide(void *, dtrace_probedesc_t *);
static void	systrace_destroy(void *, dtrace_id_t, void *);
static void	systrace_enable(void *, dtrace_id_t, void *);
static void	systrace_disable(void *, dtrace_id_t, void *);

static union {
	const char	**p_constnames;
	char		**pp_syscallnames;
} uglyhack = { SYSCALLNAMES };

static dtrace_pattr_t systrace_attr = {
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
};

static dtrace_pops_t systrace_pops = {
	.dtps_provide =		systrace_provide,
	.dtps_provide_module =	NULL,
	.dtps_enable =		systrace_enable,
	.dtps_disable =		systrace_disable,
	.dtps_suspend =		NULL,
	.dtps_resume =		NULL,
	.dtps_getargdesc =	systrace_getargdesc,
	.dtps_getargval =	systrace_getargval,
	.dtps_usermode =	NULL,
	.dtps_destroy =		systrace_destroy
};

static dtrace_provider_id_t	systrace_id;

#ifdef NATIVE_ABI
/*
 * Probe callback function.
 *
 * Note: This function is called for _all_ syscalls, regardless of which sysent
 *       array the syscall comes from. It could be a standard syscall or a
 *       compat syscall from something like Linux.
 */
static void
systrace_probe(struct syscall_args *sa, enum systrace_probe_t type, int retval)
{
	uint64_t uargs[nitems(sa->args)];
	dtrace_id_t id;
	int n_args, sysnum;

	sysnum = sa->code;
	memset(uargs, 0, sizeof(uargs));

	if (type == SYSTRACE_ENTRY) {
		if ((id = sa->callp->sy_entry) == DTRACE_IDNONE)
			return;

		if (sa->callp->sy_systrace_args_func != NULL)
			/*
			 * Convert the syscall parameters using the registered
			 * function.
			 */
			(*sa->callp->sy_systrace_args_func)(sysnum, sa->args,
			    uargs, &n_args);
		else
			/*
			 * Use the built-in system call argument conversion
			 * function to translate the syscall structure fields
			 * into the array of 64-bit values that DTrace expects.
			 */
			systrace_args(sysnum, sa->args, uargs, &n_args);
		/*
		 * Save probe arguments now so that we can retrieve them if
		 * the getargval method is called from further down the stack.
		 */
		curthread->t_dtrace_systrace_args = uargs;
	} else {
		if ((id = sa->callp->sy_return) == DTRACE_IDNONE)
			return;

		curthread->t_dtrace_systrace_args = NULL;
		/* Set arg0 and arg1 as the return value of this syscall. */
		uargs[0] = uargs[1] = retval;
	}

	/* Process the probe using the converted argments. */
	dtrace_probe(id, uargs[0], uargs[1], uargs[2], uargs[3], uargs[4]);
}
#endif

static void
systrace_getargdesc(void *arg, dtrace_id_t id, void *parg,
    dtrace_argdesc_t *desc)
{
	int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);

	if (SYSTRACE_ISENTRY((uintptr_t)parg))
		systrace_entry_setargdesc(sysnum, desc->dtargd_ndx,
		    desc->dtargd_native, sizeof(desc->dtargd_native));
	else
		systrace_return_setargdesc(sysnum, desc->dtargd_ndx,
		    desc->dtargd_native, sizeof(desc->dtargd_native));

	if (desc->dtargd_native[0] == '\0')
		desc->dtargd_ndx = DTRACE_ARGNONE;
}

static uint64_t
systrace_getargval(void *arg __unused, dtrace_id_t id __unused,
    void *parg __unused, int argno, int aframes __unused)
{
	uint64_t *uargs;

	uargs = curthread->t_dtrace_systrace_args;
	if (uargs == NULL)
		/* This is a return probe. */
		return (0);
	if (argno >= nitems(((struct syscall_args *)NULL)->args))
		return (0);
	return (uargs[argno]);
}

static void
systrace_provide(void *arg, dtrace_probedesc_t *desc)
{
	int i;

	if (desc != NULL)
		return;

	for (i = 0; i < MAXSYSCALL; i++) {
		if (dtrace_probe_lookup(systrace_id, MODNAME,
		    uglyhack.pp_syscallnames[i], "entry") != 0)
			continue;

		(void)dtrace_probe_create(systrace_id, MODNAME,
		    uglyhack.pp_syscallnames[i], "entry",
		    SYSTRACE_ARTIFICIAL_FRAMES,
		    (void *)((uintptr_t)SYSTRACE_ENTRY(i)));
		(void)dtrace_probe_create(systrace_id, MODNAME,
		    uglyhack.pp_syscallnames[i], "return",
		    SYSTRACE_ARTIFICIAL_FRAMES,
		    (void *)((uintptr_t)SYSTRACE_RETURN(i)));
	}
}

static void
systrace_destroy(void *arg, dtrace_id_t id, void *parg)
{
#ifdef DEBUG
	int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);

	/*
	 * There's nothing to do here but assert that we have actually been
	 * disabled.
	 */
	if (SYSTRACE_ISENTRY((uintptr_t)parg)) {
		ASSERT(sysent[sysnum].sy_entry == DTRACE_IDNONE);
	} else {
		ASSERT(sysent[sysnum].sy_return == DTRACE_IDNONE);
	}
#endif
}

static void
systrace_enable(void *arg, dtrace_id_t id, void *parg)
{
	int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);

	SYSENT[sysnum].sy_systrace_args_func = systrace_args;

	if (SYSTRACE_ISENTRY((uintptr_t)parg))
		SYSENT[sysnum].sy_entry = id;
	else
		SYSENT[sysnum].sy_return = id;
	systrace_enabled_count++;
	if (systrace_enabled_count == 1)
		systrace_enabled = true;
}

static void
systrace_disable(void *arg, dtrace_id_t id, void *parg)
{
	int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);

	SYSENT[sysnum].sy_systrace_args_func = NULL;
	SYSENT[sysnum].sy_entry = DTRACE_IDNONE;
	SYSENT[sysnum].sy_return = DTRACE_IDNONE;
	systrace_enabled_count--;
	if (systrace_enabled_count == 0)
		systrace_enabled = false;
}

static void
systrace_load(void *dummy __unused)
{

	if (dtrace_register(PROVNAME, &systrace_attr, DTRACE_PRIV_USER, NULL,
	    &systrace_pops, NULL, &systrace_id) != 0)
		return;

#ifdef NATIVE_ABI
	systrace_probe_func = systrace_probe;
#endif
}

static void
systrace_unload(void *dummy __unused)
{

#ifdef NATIVE_ABI
	systrace_probe_func = NULL;
#endif

	if (dtrace_unregister(systrace_id) != 0)
		return;
}

static int
systrace_modevent(module_t mod __unused, int type, void *data __unused)
{
	int error;

	error = 0;
	switch (type) {
	case MOD_LOAD:
		break;

	case MOD_UNLOAD:
		break;

	case MOD_SHUTDOWN:
		break;

	default:
		error = EOPNOTSUPP;
		break;

	}
	return (error);
}

SYSINIT(systrace_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
    systrace_load, NULL);
SYSUNINIT(systrace_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
    systrace_unload, NULL);

#ifdef LINUX_SYSTRACE
DEV_MODULE(systrace_linux, systrace_modevent, NULL);
MODULE_VERSION(systrace_linux, 1);
#ifdef __amd64__
MODULE_DEPEND(systrace_linux, linux64, 1, 1, 1);
#else
MODULE_DEPEND(systrace_linux, linux, 1, 1, 1);
#endif
MODULE_DEPEND(systrace_linux, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace_linux, opensolaris, 1, 1, 1);
#elif defined(LINUX32_SYSTRACE)
DEV_MODULE(systrace_linux32, systrace_modevent, NULL);
MODULE_VERSION(systrace_linux32, 1);
MODULE_DEPEND(systrace_linux32, linux, 1, 1, 1);
MODULE_DEPEND(systrace_linux32, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace_linux32, opensolaris, 1, 1, 1);
#elif defined(FREEBSD32_SYSTRACE)
DEV_MODULE(systrace_freebsd32, systrace_modevent, NULL);
MODULE_VERSION(systrace_freebsd32, 1);
MODULE_DEPEND(systrace_freebsd32, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace_freebsd32, opensolaris, 1, 1, 1);
#else
DEV_MODULE(systrace, systrace_modevent, NULL);
MODULE_VERSION(systrace, 1);
MODULE_DEPEND(systrace, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace, opensolaris, 1, 1, 1);
#endif