source: libcfa/src/interpose.cfa

Last change on this file was 49599a3, checked in by Thierry Delisle <tdelisle@…>, 4 weeks ago

Removed unnecessary debug

  • Property mode set to 100644
File size: 11.5 KB
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1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// interpose.c --
8//
9// Author           : Thierry Delisle
10// Created On       : Wed Mar 29 16:10:31 2017
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Fri Mar 13 17:35:37 2020
13// Update Count     : 178
14//
15
16#include <stdarg.h>                                                                             // va_start, va_end
17#include <stdio.h>
18#include <string.h>                                                                             // strlen
19#include <unistd.h>                                                                             // _exit, getpid
20#define __USE_GNU
21#include <signal.h>
22#undef __USE_GNU
23extern "C" {
24#include <dlfcn.h>                                                                              // dlopen, dlsym
25#include <execinfo.h>                                                                   // backtrace, messages
26}
27
28#include "bits/debug.hfa"
29#include "bits/defs.hfa"
30#include "bits/signal.hfa"                                                              // sigHandler_?
31#include "startup.hfa"                                                                  // STARTUP_PRIORITY_CORE
32#include <assert.h>
33
34//=============================================================================================
35// Interposing helpers
36//=============================================================================================
37
38void preload_libgcc(void) {
39        dlopen( "libgcc_s.so.1", RTLD_NOW );
40        if ( const char * error = dlerror() ) abort( "interpose_symbol : internal error pre-loading libgcc, %s\n", error );
41}
42
43typedef void (* generic_fptr_t)(void);
44generic_fptr_t interpose_symbol( const char symbol[], const char version[] ) {
45        const char * error;
46
47        static void * library;
48        if ( ! library ) {
49                #if defined( RTLD_NEXT )
50                        library = RTLD_NEXT;
51                #else
52                        // missing RTLD_NEXT => must hard-code library name, assuming libstdc++
53                        library = dlopen( "libc.so.6", RTLD_LAZY );
54                        error = dlerror();
55                        if ( error ) {
56                                abort( "interpose_symbol : failed to open libc, %s\n", error );
57                        }
58                #endif
59        } // if
60
61        union { generic_fptr_t fptr; void * ptr; } originalFunc;
62
63        #if defined( _GNU_SOURCE )
64                if ( version ) {
65                        originalFunc.ptr = dlvsym( library, symbol, version );
66                } else {
67                        originalFunc.ptr = dlsym( library, symbol );
68                }
69        #else
70                originalFunc.ptr = dlsym( library, symbol );
71        #endif // _GNU_SOURCE
72
73        error = dlerror();
74        if ( error ) abort( "interpose_symbol : internal error, %s\n", error );
75
76        return originalFunc.fptr;
77}
78
79#define INTERPOSE_LIBC( x, ver ) __cabi_libc.x = (typeof(__cabi_libc.x))interpose_symbol( #x, ver )
80
81//=============================================================================================
82// Interposition Startup logic
83//=============================================================================================
84
85void sigHandler_segv( __CFA_SIGPARMS__ );
86void sigHandler_ill ( __CFA_SIGPARMS__ );
87void sigHandler_fpe ( __CFA_SIGPARMS__ );
88void sigHandler_abrt( __CFA_SIGPARMS__ );
89void sigHandler_term( __CFA_SIGPARMS__ );
90
91struct {
92        void (* exit)( int ) __attribute__(( __noreturn__ ));
93        void (* abort)( void ) __attribute__(( __noreturn__ ));
94} __cabi_libc;
95
96int cfa_main_returned;
97
98extern "C" {
99        void __cfaabi_interpose_startup( void ) {
100                const char *version = 0p;
101                cfa_main_returned = 0;
102
103                preload_libgcc();
104
105#pragma GCC diagnostic push
106#pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
107                INTERPOSE_LIBC( abort, version );
108                INTERPOSE_LIBC( exit , version );
109#pragma GCC diagnostic pop
110
111                // As a precaution (and necessity), errors that result in termination are delivered on a separate stack because
112                // task stacks might be very small (4K) and the signal delivery corrupts memory to the point that a clean
113                // shutdown is impossible. Also, when a stack overflow encounters the non-accessible sentinel page (debug only)
114                // and generates a segment fault, the signal cannot be delivered on the sentinel page. Finally, calls to abort
115                // print a stack trace that uses substantial stack space.
116
117                #define MINSTKSZ SIGSTKSZ * 8
118                static char stack[MINSTKSZ] __attribute__(( aligned (16) ));
119                static stack_t ss;
120
121                ss.ss_sp = stack;
122                ss.ss_size = MINSTKSZ;
123                ss.ss_flags = 0;
124                if ( sigaltstack( &ss, 0p ) == -1 ) {
125                        abort( "__cfaabi_interpose_startup : internal error, sigaltstack error(%d) %s.", errno, strerror( errno ) );
126                } // if
127
128                // Failure handler
129                 // internal errors
130                __cfaabi_sigaction( SIGSEGV, sigHandler_segv, SA_SIGINFO | SA_ONSTACK ); // Invalid memory reference (default: Core)
131                __cfaabi_sigaction( SIGBUS , sigHandler_segv, SA_SIGINFO | SA_ONSTACK ); // Bus error, bad memory access (default: Core)
132                __cfaabi_sigaction( SIGILL , sigHandler_ill , SA_SIGINFO | SA_ONSTACK ); // Illegal Instruction (default: Core)
133                __cfaabi_sigaction( SIGFPE , sigHandler_fpe , SA_SIGINFO | SA_ONSTACK ); // Floating-point exception (default: Core)
134
135                // handlers to outside errors
136                // reset in-case they insist and send it over and over
137                __cfaabi_sigaction( SIGTERM, sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Termination signal (default: Term)
138                __cfaabi_sigaction( SIGINT , sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Interrupt from keyboard (default: Term)
139                __cfaabi_sigaction( SIGHUP , sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Hangup detected on controlling terminal or death of controlling process (default: Term)
140                __cfaabi_sigaction( SIGQUIT, sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Quit from keyboard (default: Core)
141                __cfaabi_sigaction( SIGABRT, sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Abort signal from abort(3) (default: Core)
142        }
143}
144
145//=============================================================================================
146// Terminating Signals logic
147//=============================================================================================
148
149// Forward declare abort after the __typeof__ call to avoid ambiguities
150void exit( int status, const char fmt[], ... ) __attribute__(( format(printf, 2, 3), __nothrow__, __leaf__, __noreturn__ ));
151void abort( const char fmt[], ... ) __attribute__(( format(printf, 1, 2), __nothrow__, __leaf__, __noreturn__ ));
152void abort( bool signalAbort, const char fmt[], ... ) __attribute__(( format(printf, 2, 3), __nothrow__, __leaf__, __noreturn__ ));
153void __abort( bool signalAbort, const char fmt[], va_list args ) __attribute__(( __nothrow__, __leaf__, __noreturn__ ));
154
155extern "C" {
156        void abort( void ) __attribute__(( __nothrow__, __leaf__, __noreturn__ )) {
157                abort( false, "%s", "" );
158        }
159
160        void __cabi_abort( const char fmt[], ... ) __attribute__(( format(printf, 1, 2), __nothrow__, __leaf__, __noreturn__ )) {
161                va_list argp;
162                va_start( argp, fmt );
163                __abort( false, fmt, argp );
164                va_end( argp );
165        }
166
167        void exit( int status ) __attribute__(( __nothrow__, __leaf__, __noreturn__ )) {
168                __cabi_libc.exit( status );
169        }
170}
171
172// See concurrency/kernel.cfa and concurrency/preemption.cfa for strong definition used in multi-processor mode.
173void __kernel_abort_lock( void ) __attribute__(( __nothrow__, __leaf__, __weak__ )) {}
174void __kernel_abort_msg( char buffer[], int size ) __attribute__(( __nothrow__, __leaf__, __weak__ )) {}
175int __kernel_abort_lastframe( void ) __attribute__(( __nothrow__, __leaf__, __weak__ )) { return 4; }
176
177enum { abort_text_size = 1024 };
178static char abort_text[ abort_text_size ];
179
180static void __cfaabi_backtrace( int start ) {
181        enum { Frames = 50, };                                                          // maximum number of stack frames
182        int last = __kernel_abort_lastframe();                          // skip last N stack frames
183
184        void * array[Frames];
185        size_t size = backtrace( array, Frames );
186        char ** messages = backtrace_symbols( array, size ); // does not demangle names
187
188        *index( messages[0], '(' ) = '\0';                                      // find executable name
189        __cfaabi_bits_print_nolock( STDERR_FILENO, "Stack back trace for: %s\n", messages[0]);
190
191        for ( unsigned int i = start; i < size - last && messages != 0p; i += 1 ) {
192                char * name = 0p, * offset_begin = 0p, * offset_end = 0p;
193
194                for ( char * p = messages[i]; *p; p += 1 ) {    // find parantheses and +offset
195                        //__cfaabi_bits_print_nolock( "X %s\n", p);
196                        if ( *p == '(' ) {
197                                name = p;
198                        } else if ( *p == '+' ) {
199                                offset_begin = p;
200                        } else if ( *p == ')' ) {
201                                offset_end = p;
202                                break;
203                        }
204                }
205
206                // if line contains symbol, print it
207                int frameNo = i - start;
208                if ( name && offset_begin && offset_end && name < offset_begin ) {
209                        *name++ = '\0';                                                         // delimit strings
210                        *offset_begin++ = '\0';
211                        *offset_end++ = '\0';
212
213                        __cfaabi_bits_print_nolock( STDERR_FILENO, "(%i) %s : %s + %s %s\n", frameNo, messages[i], name, offset_begin, offset_end);
214                } else {                                                                                // otherwise, print the whole line
215                        __cfaabi_bits_print_nolock( STDERR_FILENO, "(%i) %s\n", frameNo, messages[i] );
216                }
217        }
218        free( messages );
219}
220
221void exit( int status, const char fmt[], ... ) {
222        va_list args;
223        va_start( args, fmt );
224        vfprintf( stderr, fmt, args );
225        va_end( args );
226        __cabi_libc.exit( status );
227}
228
229static volatile bool __abort_first = 0;
230
231// Cannot forward va_list.
232void __abort( bool signalAbort, const char fmt[], va_list args ) {
233        // Multiple threads can come here from multiple paths
234        // To make sure this is safe any concurrent/subsequent call to abort is redirected to libc-abort
235        bool first = ! __atomic_test_and_set( &__abort_first, __ATOMIC_SEQ_CST);
236
237        // Prevent preemption from kicking-in and messing with the abort
238        __kernel_abort_lock();
239
240        // first to abort ?
241        if ( !first ) {
242                // We aren't the first to abort just let C handle it
243                signal( SIGABRT, SIG_DFL );     // restore default in case we came here through the function.
244                __cabi_libc.abort();
245        }
246
247        int len = snprintf( abort_text, abort_text_size, "Cforall Runtime error (UNIX pid:%ld) ", (long int)getpid() ); // use UNIX pid (versus getPid)
248        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
249
250        // print the cause of the error
251        assert( fmt );
252        len = vsnprintf( abort_text, abort_text_size, fmt, args );
253        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
254
255        // add optional newline if missing at the end of the format text
256        if ( fmt[strlen( fmt ) - 1] != '\n' ) {
257                __cfaabi_bits_write( STDERR_FILENO, "\n", 1 );
258        } // if
259
260        // Give the kernel the chance to add some data in here
261        __kernel_abort_msg( abort_text, abort_text_size );
262
263        // print stack trace in handler
264        __cfaabi_backtrace( signalAbort ? 4 : 2 );
265
266        // Finally call abort
267        __cabi_libc.abort();
268
269}
270
271void abort( const char fmt[], ... ) {
272        va_list args;
273        va_start( args, fmt );
274        __abort( false, fmt, args );
275    // CONTROL NEVER REACHES HERE!
276        va_end( args );
277}
278
279void abort( bool signalAbort, const char fmt[], ... ) {
280    va_list args;
281    va_start( args, fmt );
282    __abort( signalAbort, fmt, args );
283    // CONTROL NEVER REACHES HERE!
284    va_end( args );
285}
286
287void sigHandler_segv( __CFA_SIGPARMS__ ) {
288                if ( sfp->si_addr == 0p ) {
289                        abort( true, "Null pointer (0p) dereference.\n" );
290                } else {
291                        abort( true, "%s at memory location %p.\n"
292                                   "Possible cause is reading outside the address space or writing to a protected area within the address space with an invalid pointer or subscript.\n",
293                                   (sig == SIGSEGV ? "Segment fault" : "Bus error"), sfp->si_addr );
294                }
295}
296
297void sigHandler_ill( __CFA_SIGPARMS__ ) {
298        abort( true, "Executing illegal instruction at location %p.\n"
299                        "Possible cause is stack corruption.\n",
300                        sfp->si_addr );
301}
302
303void sigHandler_fpe( __CFA_SIGPARMS__ ) {
304        const char * msg;
305
306        choose( sfp->si_code ) {
307          case FPE_INTDIV, FPE_FLTDIV: msg = "divide by zero";
308          case FPE_FLTOVF: msg = "overflow";
309          case FPE_FLTUND: msg = "underflow";
310          case FPE_FLTRES: msg = "inexact result";
311          case FPE_FLTINV: msg = "invalid operation";
312          default: msg = "unknown";
313        } // choose
314        abort( true, "Computation error %s at location %p.\n", msg, sfp->si_addr );
315}
316
317void sigHandler_term( __CFA_SIGPARMS__ ) {
318        abort( true, "Application interrupted by signal: %s.\n", strsignal( sig ) );
319}
320
321// Local Variables: //
322// mode: c //
323// tab-width: 4 //
324// End: //
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