1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 */
25 /*
26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 */
29
30 #pragma weak fex_get_log = __fex_get_log
31 #pragma weak fex_set_log = __fex_set_log
32 #pragma weak fex_get_log_depth = __fex_get_log_depth
33 #pragma weak fex_set_log_depth = __fex_set_log_depth
34 #pragma weak fex_log_entry = __fex_log_entry
35
36 #include "fenv_synonyms.h"
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <unistd.h>
40 #include <string.h>
41 #include <signal.h>
42 #include <ucontext.h>
43 #include <sys/frame.h>
44 #include <fenv.h>
45 #include <sys/ieeefp.h>
46 #include <thread.h>
47 #include "fex_handler.h"
48
49 #if !defined(PC)
50 #if defined(REG_PC)
51 #define PC REG_PC
52 #else
53 #error Neither PC nor REG_PC is defined!
54 #endif
55 #endif
56
57 static FILE *log_fp = NULL;
58 static mutex_t log_lock = DEFAULTMUTEX;
59 static int log_depth = 100;
60
61 FILE *fex_get_log(void)
62 {
63 FILE *fp;
64
65 mutex_lock(&log_lock);
66 fp = log_fp;
67 mutex_unlock(&log_lock);
68 return fp;
69 }
70
71 int fex_set_log(FILE *fp)
72 {
73 mutex_lock(&log_lock);
74 log_fp = fp;
75 mutex_unlock(&log_lock);
76 __fex_update_te();
77 return 1;
78 }
79
80 int fex_get_log_depth(void)
81 {
82 int d;
83
84 mutex_lock(&log_lock);
85 d = log_depth;
86 mutex_unlock(&log_lock);
87 return d;
88 }
89
90 int fex_set_log_depth(int d)
91 {
92 if (d < 0)
93 return 0;
94 mutex_lock(&log_lock);
95 log_depth = d;
96 mutex_unlock(&log_lock);
97 return 1;
98 }
99
100 static struct exc_list {
101 struct exc_list *next;
102 char *addr;
103 unsigned long code;
104 int nstack;
105 char *stack[1]; /* actual length is max(1,nstack) */
106 } *list = NULL;
107
108 #ifdef __sparcv9
109 #define FRAMEP(X) (struct frame *)((char*)(X)+(((long)(X)&1)?2047:0))
110 #else
111 #define FRAMEP(X) (struct frame *)(X)
112 #endif
113
114 #ifdef _LP64
115 #define PDIG "16"
116 #else
117 #define PDIG "8"
118 #endif
119
120 /* look for a matching exc_list; return 1 if one is found,
121 otherwise add this one to the list and return 0 */
122 static int check_exc_list(char *addr, unsigned long code, char *stk,
123 struct frame *fp)
124 {
125 struct exc_list *l, *ll = NULL;
126 struct frame *f;
127 int i, n;
128
129 if (list) {
130 for (l = list; l; ll = l, l = l->next) {
131 if (l->addr != addr || l->code != code)
132 continue;
133 if (log_depth < 1 || l->nstack < 1)
134 return 1;
135 if (l->stack[0] != stk)
136 continue;
137 n = 1;
138 for (i = 1, f = fp; i < log_depth && i < l->nstack &&
139 f && f->fr_savpc; i++, f = FRAMEP(f->fr_savfp))
140 if (l->stack[i] != (char *)f->fr_savpc) {
141 n = 0;
142 break;
143 }
144 if (n)
145 return 1;
146 }
147 }
148
149 /* create a new exc_list structure and tack it on the list */
150 for (n = 1, f = fp; n < log_depth && f && f->fr_savpc;
151 n++, f = FRAMEP(f->fr_savfp)) ;
152 if ((l = (struct exc_list *)malloc(sizeof(struct exc_list) +
153 (n - 1) * sizeof(char *))) != NULL) {
154 l->next = NULL;
155 l->addr = addr;
156 l->code = code;
157 l->nstack = ((log_depth < 1)? 0 : n);
158 l->stack[0] = stk;
159 for (i = 1; i < n; i++) {
160 l->stack[i] = (char *)fp->fr_savpc;
161 fp = FRAMEP(fp->fr_savfp);
162 }
163 if (list)
164 ll->next = l;
165 else
166 list = l;
167 }
168 return 0;
169 }
170
171 /*
172 * Warning: cleverness ahead
173 *
174 * In the following code, the use of sprintf+write rather than fprintf
175 * to send output to the log file is intentional. The reason is that
176 * fprintf is not async-signal-safe. "But," you protest, "SIGFPE is
177 * not an asynchronous signal! It's always handled by the same thread
178 * that executed the fpop that provoked it." That's true, but a prob-
179 * lem arises because (i) base conversion in fprintf can cause a fp
180 * exception and (ii) my signal handler acquires a mutex lock before
181 * sending output to the log file (so that outputs for entries from
182 * different threads aren't interspersed). Therefore, if the code
183 * were to use fprintf, a deadlock could occur as follows:
184 *
185 * Thread A Thread B
186 *
187 * Incurs a fp exception, Calls fprintf,
188 * acquires log_lock acquires file rmutex lock
189 *
190 * Calls fprintf, Incurs a fp exception,
191 * waits for file rmutex lock waits for log_lock
192 *
193 * (I could just verify that fprintf doesn't hold the rmutex lock while
194 * it's doing the base conversion, but since efficiency is of little
195 * concern here, I opted for the safe and dumb route.)
196 */
197
198 static void print_stack(int fd, char *addr, struct frame *fp)
199 {
200 int i;
201 char *name, buf[30];
202
203 for (i = 0; i < log_depth && addr != NULL; i++) {
204 if (__fex_sym(addr, &name) != NULL) {
205 write(fd, buf, sprintf(buf, " 0x%0" PDIG "lx ",
206 (long)addr));
207 write(fd, name, strlen(name));
208 write(fd, "\n", 1);
209 if (!strcmp(name, "main"))
210 break;
211 } else {
212 write(fd, buf, sprintf(buf, " 0x%0" PDIG "lx\n",
213 (long)addr));
214 }
215 if (fp == NULL)
216 break;
217 addr = (char *)fp->fr_savpc;
218 fp = FRAMEP(fp->fr_savfp);
219 }
220 }
221
222 void fex_log_entry(const char *msg)
223 {
224 ucontext_t uc;
225 struct frame *fp;
226 char *stk;
227 int fd;
228
229 /* if logging is disabled, just return */
230 mutex_lock(&log_lock);
231 if (log_fp == NULL) {
232 mutex_unlock(&log_lock);
233 return;
234 }
235
236 /* get the frame pointer from the current context and
237 pop our own frame */
238 getcontext(&uc);
239 #if defined(__sparc) || defined(__amd64)
240 fp = FRAMEP(uc.uc_mcontext.gregs[REG_SP]);
241 #elif defined(__i386) /* !defined(__amd64) */
242 fp = FRAMEP(uc.uc_mcontext.gregs[EBP]);
243 #else
244 #error Unknown architecture
245 #endif
246 if (fp == NULL) {
247 mutex_unlock(&log_lock);
248 return;
249 }
250 stk = (char *)fp->fr_savpc;
251 fp = FRAMEP(fp->fr_savfp);
252
253 /* if we've already logged this message here, don't make an entry */
254 if (check_exc_list(stk, (unsigned long)msg, stk, fp)) {
255 mutex_unlock(&log_lock);
256 return;
257 }
258
259 /* make an entry */
260 fd = fileno(log_fp);
261 write(fd, "fex_log_entry: ", 15);
262 write(fd, msg, strlen(msg));
263 write(fd, "\n", 1);
264 __fex_sym_init();
265 print_stack(fd, stk, fp);
266 mutex_unlock(&log_lock);
267 }
268
269 static const char *exception[FEX_NUM_EXC] = {
270 "inexact result",
271 "division by zero",
272 "underflow",
273 "overflow",
274 "invalid operation (0/0)",
275 "invalid operation (inf/inf)",
276 "invalid operation (inf-inf)",
277 "invalid operation (0*inf)",
278 "invalid operation (sqrt)",
279 "invalid operation (snan)",
280 "invalid operation (int)",
281 "invalid operation (cmp)"
282 };
283
284 void
285 __fex_mklog(ucontext_t *uap, char *addr, int f, enum fex_exception e,
286 int m, void *p)
287 {
288 struct frame *fp;
289 char *stk, *name, buf[30];
290 int fd;
291
292 /* if logging is disabled, just return */
293 mutex_lock(&log_lock);
294 if (log_fp == NULL) {
295 mutex_unlock(&log_lock);
296 return;
297 }
298
299 /* get stack info */
300 #if defined(__sparc)
301 stk = (char*)uap->uc_mcontext.gregs[REG_PC];
302 fp = FRAMEP(uap->uc_mcontext.gregs[REG_SP]);
303 #elif defined(__amd64)
304 stk = (char*)uap->uc_mcontext.gregs[REG_PC];
305 fp = FRAMEP(uap->uc_mcontext.gregs[REG_RBP]);
306 #elif defined(__i386) /* !defined(__amd64) */
307 stk = (char*)uap->uc_mcontext.gregs[PC];
308 fp = FRAMEP(uap->uc_mcontext.gregs[EBP]);
309 #else
310 #error Unknown architecture
311 #endif
312
313 /* if the handling mode is the default and this exception's
314 flag is already raised, don't make an entry */
315 if (m == FEX_NONSTOP) {
316 switch (e) {
317 case fex_inexact:
318 if (f & FE_INEXACT) {
319 mutex_unlock(&log_lock);
320 return;
321 }
322 break;
323 case fex_underflow:
324 if (f & FE_UNDERFLOW) {
325 mutex_unlock(&log_lock);
326 return;
327 }
328 break;
329 case fex_overflow:
330 if (f & FE_OVERFLOW) {
331 mutex_unlock(&log_lock);
332 return;
333 }
334 break;
335 case fex_division:
336 if (f & FE_DIVBYZERO) {
337 mutex_unlock(&log_lock);
338 return;
339 }
340 break;
341 default:
342 if (f & FE_INVALID) {
343 mutex_unlock(&log_lock);
344 return;
345 }
346 break;
347 }
348 }
349
350 /* if we've already logged this exception at this address,
351 don't make an entry */
352 if (check_exc_list(addr, (unsigned long)e, stk, fp)) {
353 mutex_unlock(&log_lock);
354 return;
355 }
356
357 /* make an entry */
358 fd = fileno(log_fp);
359 write(fd, "Floating point ", 15);
360 write(fd, exception[e], strlen(exception[e]));
361 write(fd, buf, sprintf(buf, " at 0x%0" PDIG "lx", (long)addr));
362 __fex_sym_init();
363 if (__fex_sym(addr, &name) != NULL) {
364 write(fd, " ", 1);
365 write(fd, name, strlen(name));
366 }
367 switch (m) {
368 case FEX_NONSTOP:
369 write(fd, ", nonstop mode\n", 15);
370 break;
371
372 case FEX_ABORT:
373 write(fd, ", abort\n", 8);
374 break;
375
376 case FEX_NOHANDLER:
377 if (p == (void *)SIG_DFL) {
378 write(fd, ", handler: SIG_DFL\n", 19);
379 break;
380 }
381 else if (p == (void *)SIG_IGN) {
382 write(fd, ", handler: SIG_IGN\n", 19);
383 break;
384 }
385 /* fall through*/
386 default:
387 write(fd, ", handler: ", 11);
388 if (__fex_sym((char *)p, &name) != NULL) {
389 write(fd, name, strlen(name));
390 write(fd, "\n", 1);
391 } else {
392 write(fd, buf, sprintf(buf, "0x%0" PDIG "lx\n",
393 (long)p));
394 }
395 break;
396 }
397 print_stack(fd, stk, fp);
398 mutex_unlock(&log_lock);
399 }