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root/cebix/BasiliskII/src/Unix/sigsegv.cpp
Revision: 1.10
Committed: 2002-05-12T11:10:50Z (22 years, 5 months ago) by gbeauche
Branch: MAIN
Changes since 1.9: +257 -2 lines
Log Message:
Implement the "ignoresegv" feature from SheepShaver. This is Unix-specific
so far. Target platform is currently Linux/x86.

File Contents

# User Rev Content
1 gbeauche 1.1 /*
2     * sigsegv.cpp - SIGSEGV signals support
3     *
4     * Derived from Bruno Haible's work on his SIGSEGV library for clisp
5     * <http://clisp.sourceforge.net/>
6     *
7 cebix 1.7 * Basilisk II (C) 1997-2002 Christian Bauer
8 gbeauche 1.1 *
9     * This program is free software; you can redistribute it and/or modify
10     * it under the terms of the GNU General Public License as published by
11     * the Free Software Foundation; either version 2 of the License, or
12     * (at your option) any later version.
13     *
14     * This program is distributed in the hope that it will be useful,
15     * but WITHOUT ANY WARRANTY; without even the implied warranty of
16     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17     * GNU General Public License for more details.
18     *
19     * You should have received a copy of the GNU General Public License
20     * along with this program; if not, write to the Free Software
21     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22     */
23    
24     #ifdef HAVE_UNISTD_H
25     #include <unistd.h>
26     #endif
27    
28     #ifdef HAVE_CONFIG_H
29     #include "config.h"
30     #endif
31    
32     #include <signal.h>
33     #include "sigsegv.h"
34    
35     // Return value type of a signal handler (standard type if not defined)
36     #ifndef RETSIGTYPE
37     #define RETSIGTYPE void
38     #endif
39    
40     // Type of the system signal handler
41     typedef RETSIGTYPE (*signal_handler)(int);
42    
43 gbeauche 1.10 // Is the fault to be ignored?
44     static bool sigsegv_ignore_fault = false;
45    
46 gbeauche 1.1 // User's SIGSEGV handler
47     static sigsegv_handler_t sigsegv_user_handler = 0;
48    
49 gbeauche 1.10 // Function called to dump state if we can't handle the fault
50     static sigsegv_handler_t sigsegv_dump_state = 0;
51    
52 gbeauche 1.1 // Actual SIGSEGV handler installer
53     static bool sigsegv_do_install_handler(int sig);
54    
55    
56     /*
57     * OS-dependant SIGSEGV signals support section
58     */
59    
60     #if HAVE_SIGINFO_T
61     // Generic extended signal handler
62 cebix 1.8 #if defined(__NetBSD__) || defined(__FreeBSD__)
63     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS)
64     #else
65 gbeauche 1.1 #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
66 cebix 1.8 #endif
67 gbeauche 1.5 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, siginfo_t *sip, void *scp
68 gbeauche 1.1 #define SIGSEGV_FAULT_ADDRESS sip->si_addr
69 gbeauche 1.5 #if defined(__linux__)
70 gbeauche 1.6 #if (defined(i386) || defined(__i386__))
71     #include <sys/ucontext.h>
72     #define SIGSEGV_FAULT_INSTRUCTION (((ucontext_t *)scp)->uc_mcontext.gregs[14]) /* should use REG_EIP instead */
73 gbeauche 1.10 #define SIGSEGV_REGISTER_FILE (unsigned long *)(((ucontext_t *)scp)->uc_mcontext.gregs)
74     #define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
75 gbeauche 1.6 #endif
76 gbeauche 1.5 #if (defined(ia64) || defined(__ia64__))
77     #define SIGSEGV_FAULT_INSTRUCTION (((struct sigcontext *)scp)->sc_ip & ~0x3ULL) /* slot number is in bits 0 and 1 */
78     #endif
79 gbeauche 1.9 #if (defined(powerpc) || defined(__powerpc__))
80     #include <sys/ucontext.h>
81     #define SIGSEGV_FAULT_INSTRUCTION (((ucontext_t *)scp)->uc_mcontext.regs->nip)
82     #endif
83 gbeauche 1.5 #endif
84 gbeauche 1.1 #endif
85    
86     #if HAVE_SIGCONTEXT_SUBTERFUGE
87     // Linux kernels prior to 2.4 ?
88     #if defined(__linux__)
89     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
90     #if (defined(i386) || defined(__i386__))
91     #include <asm/sigcontext.h>
92     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext scs
93     #define SIGSEGV_FAULT_ADDRESS scs.cr2
94     #define SIGSEGV_FAULT_INSTRUCTION scs.eip
95 gbeauche 1.10 #define SIGSEGV_REGISTER_FILE (unsigned long *)(&scs)
96     #define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
97 gbeauche 1.1 #endif
98     #if (defined(sparc) || defined(__sparc__))
99     #include <asm/sigcontext.h>
100 gbeauche 1.5 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp, char *addr
101 gbeauche 1.1 #define SIGSEGV_FAULT_ADDRESS addr
102     #endif
103     #if (defined(powerpc) || defined(__powerpc__))
104     #include <asm/sigcontext.h>
105 gbeauche 1.4 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext *scp
106 gbeauche 1.1 #define SIGSEGV_FAULT_ADDRESS scp->regs->dar
107     #define SIGSEGV_FAULT_INSTRUCTION scp->regs->nip
108     #endif
109 gbeauche 1.4 #if (defined(alpha) || defined(__alpha__))
110     #include <asm/sigcontext.h>
111     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
112     #define SIGSEGV_FAULT_ADDRESS get_fault_address(scp)
113     #define SIGSEGV_FAULT_INSTRUCTION scp->sc_pc
114    
115     // From Boehm's GC 6.0alpha8
116     static sigsegv_address_t get_fault_address(struct sigcontext *scp)
117     {
118     unsigned int instruction = *((unsigned int *)(scp->sc_pc));
119     unsigned long fault_address = scp->sc_regs[(instruction >> 16) & 0x1f];
120     fault_address += (signed long)(signed short)(instruction & 0xffff);
121     return (sigsegv_address_t)fault_address;
122     }
123     #endif
124 gbeauche 1.1 #endif
125    
126     // Irix 5 or 6 on MIPS
127     #if (defined(sgi) || defined(__sgi)) && (defined(SYSTYPE_SVR4) || defined(__SYSTYPE_SVR4))
128     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
129     #define SIGSEGV_FAULT_ADDRESS scp->sc_badvaddr
130     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
131     #endif
132    
133     // OSF/1 on Alpha
134     #if defined(__osf__)
135     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
136     #define SIGSEGV_FAULT_ADDRESS scp->sc_traparg_a0
137     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
138     #endif
139    
140     // AIX
141     #if defined(_AIX)
142     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
143     #define SIGSEGV_FAULT_ADDRESS scp->sc_jmpbuf.jmp_context.o_vaddr
144     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
145     #endif
146    
147     // NetBSD or FreeBSD
148     #if defined(__NetBSD__) || defined(__FreeBSD__)
149     #if (defined(m68k) || defined(__m68k__))
150     #include <m68k/frame.h>
151     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
152     #define SIGSEGV_FAULT_ADDRESS ({ \
153     struct sigstate { \
154     int ss_flags; \
155     struct frame ss_frame; \
156     }; \
157     struct sigstate *state = (struct sigstate *)scp->sc_ap; \
158     char *fault_addr; \
159     switch (state->ss_frame.f_format) { \
160     case 7: /* 68040 access error */ \
161     /* "code" is sometimes unreliable (i.e. contains NULL or a bogus address), reason unknown */ \
162     fault_addr = state->ss_frame.f_fmt7.f_fa; \
163     break; \
164     default: \
165     fault_addr = (char *)code; \
166     break; \
167     } \
168     fault_addr; \
169     })
170     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
171     #else
172     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, void *scp, char *addr
173     #define SIGSEGV_FAULT_ADDRESS addr
174     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS)
175     #endif
176     #endif
177 gbeauche 1.4
178     // MacOS X
179     #if defined(__APPLE__) && defined(__MACH__)
180     #if (defined(ppc) || defined(__ppc__))
181     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
182     #define SIGSEGV_FAULT_ADDRESS get_fault_address(scp)
183     #define SIGSEGV_FAULT_INSTRUCTION scp->sc_ir
184     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS)
185    
186     // From Boehm's GC 6.0alpha8
187     #define EXTRACT_OP1(iw) (((iw) & 0xFC000000) >> 26)
188     #define EXTRACT_OP2(iw) (((iw) & 0x000007FE) >> 1)
189     #define EXTRACT_REGA(iw) (((iw) & 0x001F0000) >> 16)
190     #define EXTRACT_REGB(iw) (((iw) & 0x03E00000) >> 21)
191     #define EXTRACT_REGC(iw) (((iw) & 0x0000F800) >> 11)
192     #define EXTRACT_DISP(iw) ((short *) &(iw))[1]
193    
194     static sigsegv_address_t get_fault_address(struct sigcontext *scp)
195     {
196     unsigned int instr = *((unsigned int *) scp->sc_ir);
197     unsigned int * regs = &((unsigned int *) scp->sc_regs)[2];
198     int disp = 0, tmp;
199     unsigned int baseA = 0, baseB = 0;
200     unsigned int addr, alignmask = 0xFFFFFFFF;
201    
202     switch(EXTRACT_OP1(instr)) {
203     case 38: /* stb */
204     case 39: /* stbu */
205     case 54: /* stfd */
206     case 55: /* stfdu */
207     case 52: /* stfs */
208     case 53: /* stfsu */
209     case 44: /* sth */
210     case 45: /* sthu */
211     case 47: /* stmw */
212     case 36: /* stw */
213     case 37: /* stwu */
214     tmp = EXTRACT_REGA(instr);
215     if(tmp > 0)
216     baseA = regs[tmp];
217     disp = EXTRACT_DISP(instr);
218     break;
219     case 31:
220     switch(EXTRACT_OP2(instr)) {
221     case 86: /* dcbf */
222     case 54: /* dcbst */
223     case 1014: /* dcbz */
224     case 247: /* stbux */
225     case 215: /* stbx */
226     case 759: /* stfdux */
227     case 727: /* stfdx */
228     case 983: /* stfiwx */
229     case 695: /* stfsux */
230     case 663: /* stfsx */
231     case 918: /* sthbrx */
232     case 439: /* sthux */
233     case 407: /* sthx */
234     case 661: /* stswx */
235     case 662: /* stwbrx */
236     case 150: /* stwcx. */
237     case 183: /* stwux */
238     case 151: /* stwx */
239     case 135: /* stvebx */
240     case 167: /* stvehx */
241     case 199: /* stvewx */
242     case 231: /* stvx */
243     case 487: /* stvxl */
244     tmp = EXTRACT_REGA(instr);
245     if(tmp > 0)
246     baseA = regs[tmp];
247     baseB = regs[EXTRACT_REGC(instr)];
248     /* determine Altivec alignment mask */
249     switch(EXTRACT_OP2(instr)) {
250     case 167: /* stvehx */
251     alignmask = 0xFFFFFFFE;
252     break;
253     case 199: /* stvewx */
254     alignmask = 0xFFFFFFFC;
255     break;
256     case 231: /* stvx */
257     alignmask = 0xFFFFFFF0;
258     break;
259     case 487: /* stvxl */
260     alignmask = 0xFFFFFFF0;
261     break;
262     }
263     break;
264     case 725: /* stswi */
265     tmp = EXTRACT_REGA(instr);
266     if(tmp > 0)
267     baseA = regs[tmp];
268     break;
269     default: /* ignore instruction */
270     return 0;
271     break;
272     }
273     break;
274     default: /* ignore instruction */
275     return 0;
276     break;
277     }
278    
279     addr = (baseA + baseB) + disp;
280     addr &= alignmask;
281     return (sigsegv_address_t)addr;
282     }
283     #endif
284     #endif
285 gbeauche 1.1 #endif
286    
287 gbeauche 1.10 #ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION
288     // Decode and skip X86 instruction
289     #if (defined(i386) || defined(__i386__))
290     #if defined(__linux__)
291     enum {
292     X86_REG_EIP = 14,
293     X86_REG_EAX = 11,
294     X86_REG_ECX = 10,
295     X86_REG_EDX = 9,
296     X86_REG_EBX = 8,
297     X86_REG_ESP = 7,
298     X86_REG_EBP = 6,
299     X86_REG_ESI = 5,
300     X86_REG_EDI = 4
301     };
302     #endif
303     // FIXME: this is partly redundant with the instruction decoding phase
304     // to discover transfer type and register number
305     static inline int ix86_step_over_modrm(unsigned char * p)
306     {
307     int mod = (p[0] >> 6) & 3;
308     int rm = p[0] & 7;
309     int offset = 0;
310    
311     // ModR/M Byte
312     switch (mod) {
313     case 0: // [reg]
314     if (rm == 5) return 4; // disp32
315     break;
316     case 1: // disp8[reg]
317     offset = 1;
318     break;
319     case 2: // disp32[reg]
320     offset = 4;
321     break;
322     case 3: // register
323     return 0;
324     }
325    
326     // SIB Byte
327     if (rm == 4) {
328     if (mod == 0 && (p[1] & 7) == 5)
329     offset = 5; // disp32[index]
330     else
331     offset++;
332     }
333    
334     return offset;
335     }
336    
337     static bool ix86_skip_instruction(sigsegv_address_t fault_instruction, unsigned long * regs)
338     {
339     unsigned char * eip = (unsigned char *)fault_instruction;
340    
341     if (eip == 0)
342     return false;
343    
344     // Transfer type
345     enum {
346     TYPE_UNKNOWN,
347     TYPE_LOAD,
348     TYPE_STORE
349     } transfer_type = TYPE_UNKNOWN;
350    
351     // Transfer size
352     enum {
353     SIZE_BYTE,
354     SIZE_WORD,
355     SIZE_LONG
356     } transfer_size = SIZE_LONG;
357    
358     int reg = -1;
359     int len = 0;
360    
361     // Operand size prefix
362     if (*eip == 0x66) {
363     eip++;
364     len++;
365     transfer_size = SIZE_WORD;
366     }
367    
368     // Decode instruction
369     switch (eip[0]) {
370     case 0x8a: // MOV r8, r/m8
371     transfer_size = SIZE_BYTE;
372     case 0x8b: // MOV r32, r/m32 (or 16-bit operation)
373     switch (eip[1] & 0xc0) {
374     case 0x80:
375     reg = (eip[1] >> 3) & 7;
376     transfer_type = TYPE_LOAD;
377     break;
378     case 0x40:
379     reg = (eip[1] >> 3) & 7;
380     transfer_type = TYPE_LOAD;
381     break;
382     case 0x00:
383     reg = (eip[1] >> 3) & 7;
384     transfer_type = TYPE_LOAD;
385     break;
386     }
387     len += 2 + ix86_step_over_modrm(eip + 1);
388     break;
389     case 0x88: // MOV r/m8, r8
390     transfer_size = SIZE_BYTE;
391     case 0x89: // MOV r/m32, r32 (or 16-bit operation)
392     switch (eip[1] & 0xc0) {
393     case 0x80:
394     reg = (eip[1] >> 3) & 7;
395     transfer_type = TYPE_STORE;
396     break;
397     case 0x40:
398     reg = (eip[1] >> 3) & 7;
399     transfer_type = TYPE_STORE;
400     break;
401     case 0x00:
402     reg = (eip[1] >> 3) & 7;
403     transfer_type = TYPE_STORE;
404     break;
405     }
406     len += 2 + ix86_step_over_modrm(eip + 1);
407     break;
408     }
409    
410     if (transfer_type == TYPE_UNKNOWN) {
411     // Unknown machine code, let it crash. Then patch the decoder
412     return false;
413     }
414    
415     if (transfer_type == TYPE_LOAD && reg != -1) {
416     static const int x86_reg_map[8] = {
417     X86_REG_EAX, X86_REG_ECX, X86_REG_EDX, X86_REG_EBX,
418     X86_REG_ESP, X86_REG_EBP, X86_REG_ESI, X86_REG_EDI
419     };
420    
421     if (reg < 0 || reg >= 8)
422     return false;
423    
424     int rloc = x86_reg_map[reg];
425     switch (transfer_size) {
426     case SIZE_BYTE:
427     regs[rloc] = (regs[rloc] & ~0xff);
428     break;
429     case SIZE_WORD:
430     regs[rloc] = (regs[rloc] & ~0xffff);
431     break;
432     case SIZE_LONG:
433     regs[rloc] = 0;
434     break;
435     }
436     }
437    
438     #if DEBUG
439     printf("%08x: %s %s access", regs[X86_REG_EIP],
440     transfer_size == SIZE_BYTE ? "byte" : transfer_size == SIZE_WORD ? "word" : "long",
441     transfer_type == TYPE_LOAD ? "read" : "write");
442    
443     if (reg != -1) {
444     static const char * x86_reg_str_map[8] = {
445     "eax", "ecx", "edx", "ebx",
446     "esp", "ebp", "esi", "edi"
447     };
448     printf(" %s register %%%s", transfer_type == TYPE_LOAD ? "to" : "from", x86_reg_str_map[reg]);
449     }
450     printf(", %d bytes instruction\n", len);
451     #endif
452    
453     regs[X86_REG_EIP] += len;
454     return true;
455     }
456     #endif
457     #endif
458    
459 gbeauche 1.1 // Fallbacks
460     #ifndef SIGSEGV_FAULT_INSTRUCTION
461     #define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_INVALID_PC
462     #endif
463    
464 gbeauche 1.2 // SIGSEGV recovery supported ?
465     #if defined(SIGSEGV_ALL_SIGNALS) && defined(SIGSEGV_FAULT_HANDLER_ARGLIST) && defined(SIGSEGV_FAULT_ADDRESS)
466     #define HAVE_SIGSEGV_RECOVERY
467     #endif
468    
469 gbeauche 1.1
470     /*
471     * SIGSEGV global handler
472     */
473    
474 gbeauche 1.2 #ifdef HAVE_SIGSEGV_RECOVERY
475 gbeauche 1.1 static void sigsegv_handler(SIGSEGV_FAULT_HANDLER_ARGLIST)
476     {
477 gbeauche 1.10 sigsegv_address_t fault_address = (sigsegv_address_t)SIGSEGV_FAULT_ADDRESS;
478     sigsegv_address_t fault_instruction = (sigsegv_address_t)SIGSEGV_FAULT_INSTRUCTION;
479     bool fault_recovered = false;
480    
481 gbeauche 1.1 // Call user's handler and reinstall the global handler, if required
482 gbeauche 1.10 if (sigsegv_user_handler(fault_address, fault_instruction)) {
483 gbeauche 1.1 #if (defined(HAVE_SIGACTION) ? defined(SIGACTION_NEED_REINSTALL) : defined(SIGNAL_NEED_REINSTALL))
484     sigsegv_do_install_handler(sig);
485     #endif
486 gbeauche 1.10 fault_recovered = true;
487 gbeauche 1.1 }
488 gbeauche 1.10 #if HAVE_SIGSEGV_SKIP_INSTRUCTION
489     else if (sigsegv_ignore_fault) {
490     // Call the instruction skipper with the register file available
491     if (SIGSEGV_SKIP_INSTRUCTION(fault_instruction, SIGSEGV_REGISTER_FILE))
492     fault_recovered = true;
493     }
494     #endif
495    
496     if (!fault_recovered) {
497 gbeauche 1.1 // FAIL: reinstall default handler for "safe" crash
498     #define FAULT_HANDLER(sig) signal(sig, SIG_DFL);
499     SIGSEGV_ALL_SIGNALS
500     #undef FAULT_HANDLER
501 gbeauche 1.10
502     // We can't do anything with the fault_address, dump state?
503     if (sigsegv_dump_state != 0)
504     sigsegv_dump_state(fault_address, fault_instruction);
505 gbeauche 1.1 }
506     }
507 gbeauche 1.2 #endif
508 gbeauche 1.1
509    
510     /*
511     * SIGSEGV handler initialization
512     */
513    
514     #if defined(HAVE_SIGINFO_T)
515     static bool sigsegv_do_install_handler(int sig)
516     {
517     // Setup SIGSEGV handler to process writes to frame buffer
518     #ifdef HAVE_SIGACTION
519     struct sigaction vosf_sa;
520     sigemptyset(&vosf_sa.sa_mask);
521     vosf_sa.sa_sigaction = sigsegv_handler;
522     vosf_sa.sa_flags = SA_SIGINFO;
523     return (sigaction(sig, &vosf_sa, 0) == 0);
524     #else
525     return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR);
526     #endif
527     }
528 gbeauche 1.2 #endif
529    
530     #if defined(HAVE_SIGCONTEXT_SUBTERFUGE)
531 gbeauche 1.1 static bool sigsegv_do_install_handler(int sig)
532     {
533     // Setup SIGSEGV handler to process writes to frame buffer
534     #ifdef HAVE_SIGACTION
535     struct sigaction vosf_sa;
536     sigemptyset(&vosf_sa.sa_mask);
537     vosf_sa.sa_handler = (signal_handler)sigsegv_handler;
538     #if !EMULATED_68K && defined(__NetBSD__)
539     sigaddset(&vosf_sa.sa_mask, SIGALRM);
540     vosf_sa.sa_flags = SA_ONSTACK;
541     #else
542     vosf_sa.sa_flags = 0;
543     #endif
544     return (sigaction(sig, &vosf_sa, 0) == 0);
545     #else
546     return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR);
547     #endif
548     }
549     #endif
550    
551     bool sigsegv_install_handler(sigsegv_handler_t handler)
552     {
553 gbeauche 1.2 #ifdef HAVE_SIGSEGV_RECOVERY
554 gbeauche 1.1 sigsegv_user_handler = handler;
555     bool success = true;
556     #define FAULT_HANDLER(sig) success = success && sigsegv_do_install_handler(sig);
557     SIGSEGV_ALL_SIGNALS
558     #undef FAULT_HANDLER
559     return success;
560     #else
561     // FAIL: no siginfo_t nor sigcontext subterfuge is available
562     return false;
563     #endif
564     }
565    
566    
567     /*
568     * SIGSEGV handler deinitialization
569     */
570    
571     void sigsegv_deinstall_handler(void)
572     {
573 gbeauche 1.2 #ifdef HAVE_SIGSEGV_RECOVERY
574 gbeauche 1.1 sigsegv_user_handler = 0;
575     #define FAULT_HANDLER(sig) signal(sig, SIG_DFL);
576     SIGSEGV_ALL_SIGNALS
577     #undef FAULT_HANDLER
578 gbeauche 1.2 #endif
579 gbeauche 1.1 }
580    
581 gbeauche 1.10
582     /*
583     * SIGSEGV ignore state modifier
584     */
585    
586     void sigsegv_set_ignore_state(bool ignore_fault)
587     {
588     sigsegv_ignore_fault = ignore_fault;
589     }
590    
591    
592     /*
593     * Set callback function when we cannot handle the fault
594     */
595    
596     void sigsegv_set_dump_state(sigsegv_handler_t handler)
597     {
598     sigsegv_dump_state = handler;
599     }
600    
601    
602 gbeauche 1.1 /*
603     * Test program used for configure/test
604     */
605    
606 gbeauche 1.4 #ifdef CONFIGURE_TEST_SIGSEGV_RECOVERY
607 gbeauche 1.1 #include <stdio.h>
608     #include <stdlib.h>
609     #include <fcntl.h>
610     #include <sys/mman.h>
611 gbeauche 1.4 #include "vm_alloc.h"
612 gbeauche 1.1
613     static int page_size;
614 gbeauche 1.3 static volatile char * page = 0;
615     static volatile int handler_called = 0;
616 gbeauche 1.1
617     static bool sigsegv_test_handler(sigsegv_address_t fault_address, sigsegv_address_t instruction_address)
618     {
619     handler_called++;
620     if ((fault_address - 123) != page)
621     exit(1);
622 gbeauche 1.4 if (vm_protect((char *)((unsigned long)fault_address & -page_size), page_size, VM_PAGE_READ | VM_PAGE_WRITE) != 0)
623 gbeauche 1.1 exit(1);
624     return true;
625     }
626    
627 gbeauche 1.10 #ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION
628     static bool sigsegv_insn_handler(sigsegv_address_t fault_address, sigsegv_address_t instruction_address)
629     {
630     return false;
631     }
632     #endif
633    
634 gbeauche 1.1 int main(void)
635     {
636 gbeauche 1.4 if (vm_init() < 0)
637 gbeauche 1.1 return 1;
638    
639     page_size = getpagesize();
640 gbeauche 1.4 if ((page = (char *)vm_acquire(page_size)) == VM_MAP_FAILED)
641     return 1;
642    
643     if (vm_protect((char *)page, page_size, VM_PAGE_READ) < 0)
644 gbeauche 1.1 return 1;
645    
646     if (!sigsegv_install_handler(sigsegv_test_handler))
647     return 1;
648    
649     page[123] = 45;
650     page[123] = 45;
651    
652     if (handler_called != 1)
653     return 1;
654 gbeauche 1.10
655     #ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION
656     if (!sigsegv_install_handler(sigsegv_insn_handler))
657     return 1;
658    
659     if (vm_protect((char *)page, page_size, VM_PAGE_WRITE) < 0)
660     return 1;
661    
662     for (int i = 0; i < page_size; i++)
663     page[i] = (i + 1) % page_size;
664    
665     if (vm_protect((char *)page, page_size, VM_PAGE_NOACCESS) < 0)
666     return 1;
667    
668     sigsegv_set_ignore_state(true);
669    
670     #define TEST_SKIP_INSTRUCTION(TYPE) do { \
671     const unsigned int TAG = 0x12345678; \
672     TYPE data = *((TYPE *)(page + sizeof(TYPE))); \
673     volatile unsigned int effect = data + TAG; \
674     if (effect != TAG) \
675     return 1; \
676     } while (0)
677    
678     TEST_SKIP_INSTRUCTION(unsigned char);
679     TEST_SKIP_INSTRUCTION(unsigned short);
680     TEST_SKIP_INSTRUCTION(unsigned int);
681     #endif
682 gbeauche 1.1
683 gbeauche 1.4 vm_exit();
684 gbeauche 1.1 return 0;
685     }
686     #endif