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