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 : Thu Jan 11 18:45:31 2024
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13 | // Update Count : 218
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14 | //
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15 |
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16 | #include <stdio.h>
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17 | #include <unistd.h> // _exit, getpid
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18 | extern "C" {
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19 | #include <dlfcn.h> // dlopen, dlsym
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20 | //#include <link.h> // dl_iterate_phdr
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21 | struct dl_phdr_info;
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22 | int dl_iterate_phdr( int (*)( struct dl_phdr_info *, size_t, void * ), void * );
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23 | #include <execinfo.h> // backtrace, messages
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24 | }
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25 |
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26 | #include "bits/defs.hfa"
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27 | #include "bits/signal.hfa" // sigHandler_?
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28 | #include "concurrency/kernel/fwd.hfa" // disable_interrupts, enable_interrupts
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29 | #include "startup.hfa" // STARTUP_PRIORITY_CORE
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30 | #include <assert.h>
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31 |
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32 | //=============================================================================================
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33 | // Interposing helpers
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34 | //=============================================================================================
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35 |
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36 | static void preload_libgcc(void) {
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37 | dlopen( "libgcc_s.so.1", RTLD_NOW );
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38 | if ( const char * error = dlerror() ) abort( "interpose_symbol : internal error pre-loading libgcc, %s\n", error );
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39 | }
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40 |
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41 | typedef void (* generic_fptr_t)(void);
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42 |
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43 | static generic_fptr_t do_interpose_symbol( void * library, const char symbol[], const char version[] ) {
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44 | union { generic_fptr_t fptr; void * ptr; } originalFunc;
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45 |
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46 | #if defined( _GNU_SOURCE )
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47 | if ( version ) {
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48 | originalFunc.ptr = dlvsym( library, symbol, version );
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49 | } else {
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50 | originalFunc.ptr = dlsym( library, symbol );
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51 | } // if
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52 | #else
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53 | originalFunc.ptr = dlsym( library, symbol );
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54 | #endif // _GNU_SOURCE
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55 |
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56 | if ( ! originalFunc.ptr ) { // == nullptr
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57 | abort( "interpose_symbol : internal error, %s\n", dlerror() );
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58 | } // if
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59 | return originalFunc.fptr;
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60 | }
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61 |
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62 | static generic_fptr_t interpose_symbol( const char symbol[], const char version[] ) {
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63 | void * library;
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64 |
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65 | #if defined( RTLD_NEXT )
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66 | library = RTLD_NEXT;
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67 | #else
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68 | // missing RTLD_NEXT => must hard-code library name, assuming libstdc++
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69 | library = dlopen( "libc.so.6", RTLD_LAZY );
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70 | if ( ! library ) { // == nullptr
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71 | abort( "interpose_symbol : failed to open libc, %s\n", dlerror() );
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72 | } // if
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73 | #endif // RTLD_NEXT
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74 |
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75 | return do_interpose_symbol( library, symbol, version );
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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 | static void sigHandler_segv( __CFA_SIGPARMS__ );
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85 | static void sigHandler_ill ( __CFA_SIGPARMS__ );
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86 | static void sigHandler_fpe ( __CFA_SIGPARMS__ );
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87 | static void sigHandler_abrt( __CFA_SIGPARMS__ );
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88 | static void sigHandler_term( __CFA_SIGPARMS__ );
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89 |
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90 | static 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 | int (* dl_iterate_phdr)( int (*)( struct dl_phdr_info *, size_t, void * ), void * );
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94 | } __cabi_libc;
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95 |
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96 | libcfa_public int cfa_main_returned;
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97 |
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98 | extern "C" {
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99 | void __cfathreadabi_interpose_startup( generic_fptr_t (*do_interpose_symbol)( void * library, const char symbol[], const char version[] ) ) __attribute__((weak));
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100 | void __cfaabi_interpose_startup( void ) {
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101 | const char *version = 0p;
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102 | cfa_main_returned = 0;
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103 |
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104 | preload_libgcc();
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105 |
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106 | #pragma GCC diagnostic push
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107 | #pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
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108 | INTERPOSE_LIBC( abort, version );
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109 | INTERPOSE_LIBC( exit, version );
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110 | INTERPOSE_LIBC( dl_iterate_phdr, version );
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111 | #pragma GCC diagnostic pop
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112 |
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113 | if(__cfathreadabi_interpose_startup) __cfathreadabi_interpose_startup( do_interpose_symbol );
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114 |
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115 | // SKULLDUGGERY: In Ubuntu 22.04, someone augmented signal.h to allow SIGSTKSZ to be "sysconf(_SC_SIGSTKSZ)" in
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116 | // sigstksz.h, as well as 8192 in sigstack.h. HOWEVER, they forgot to provide a mechanism to tell signal.h to
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117 | // use sigstack.h rather than sigstksz.h. (I'm not happy.) By undefining _GNU_SOURCE before signal.h and
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118 | // redefining it afterwards, you can get 8192, but then nothing works correctly inside of signal.h without
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119 | // _GNU_SOURCE defined. So what is needed is a way to get signal.h to use sigstack.h WITH _GNU_SOURCE defined.
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120 | // Basically something is wrong with features.h and its use in signal.h.
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121 |
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122 | #undef SIGSTKSZ
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123 | #define SIGSTKSZ 8192
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124 |
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125 | // As a precaution (and necessity), errors that result in termination are delivered on a separate stack because
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126 | // task stacks might be very small (4K) and the signal delivery corrupts memory to the point that a clean
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127 | // shutdown is impossible. Also, when a stack overflow encounters the non-accessible sentinel page (debug only)
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128 | // and generates a segment fault, the signal cannot be delivered on the sentinel page. Finally, calls to abort
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129 | // print a stack trace that uses substantial stack space.
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130 |
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131 | #define MINSTKSZ SIGSTKSZ * 8
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132 | static char stack[MINSTKSZ] __attribute__(( aligned (16) ));
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133 | static stack_t ss;
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134 |
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135 | ss.ss_sp = stack;
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136 | ss.ss_size = MINSTKSZ;
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137 | ss.ss_flags = 0;
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138 | if ( sigaltstack( &ss, 0p ) == -1 ) {
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139 | abort( "__cfaabi_interpose_startup : internal error, sigaltstack error(%d) %s.", errno, strerror( errno ) );
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140 | } // if
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141 |
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142 | // Failure handler
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143 | // internal errors
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144 | __cfaabi_sigaction( SIGSEGV, sigHandler_segv, SA_SIGINFO | SA_ONSTACK ); // Invalid memory reference (default: Core)
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145 | __cfaabi_sigaction( SIGBUS , sigHandler_segv, SA_SIGINFO | SA_ONSTACK ); // Bus error, bad memory access (default: Core)
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146 | __cfaabi_sigaction( SIGILL , sigHandler_ill , SA_SIGINFO | SA_ONSTACK ); // Illegal Instruction (default: Core)
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147 | __cfaabi_sigaction( SIGFPE , sigHandler_fpe , SA_SIGINFO | SA_ONSTACK ); // Floating-point exception (default: Core)
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148 |
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149 | // handlers to outside errors
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150 | // reset in-case they insist and send it over and over
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151 | __cfaabi_sigaction( SIGTERM, sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Termination signal (default: Term)
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152 | __cfaabi_sigaction( SIGINT , sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Interrupt from keyboard (default: Term)
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153 | __cfaabi_sigaction( SIGHUP , sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Hangup detected on controlling terminal or death of controlling process (default: Term)
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154 | __cfaabi_sigaction( SIGQUIT, sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Quit from keyboard (default: Core)
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155 | __cfaabi_sigaction( SIGABRT, sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Abort signal from abort(3) (default: Core)
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156 | }
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157 | }
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158 |
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159 | extern "C" int dl_iterate_phdr( int (* callback)( struct dl_phdr_info *, size_t, void * ), void * data ) {
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160 | disable_interrupts();
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161 | int ret = __cabi_libc.dl_iterate_phdr( callback, data ); // call real routine
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162 | enable_interrupts( false );
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163 | return ret;
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164 | } // dl_iterate_phdr
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165 |
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166 | //=============================================================================================
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167 | // Terminating Signals logic
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168 | //=============================================================================================
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169 |
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170 | // Forward declare abort after the __typeof__ call to avoid ambiguities
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171 | libcfa_public void exit( int status, const char fmt[], ... ) __attribute__(( format(printf, 2, 3), __nothrow__, __leaf__, __noreturn__ ));
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172 | libcfa_public void abort( const char fmt[], ... ) __attribute__(( format(printf, 1, 2), __nothrow__, __leaf__, __noreturn__ ));
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173 | libcfa_public void abort( bool signalAbort, const char fmt[], ... ) __attribute__(( format(printf, 2, 3), __nothrow__, __leaf__, __noreturn__ ));
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174 | libcfa_public void __abort( bool signalAbort, const char fmt[], va_list args ) __attribute__(( __nothrow__, __leaf__, __noreturn__ ));
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175 |
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176 | extern "C" {
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177 | libcfa_public void abort( void ) __attribute__(( __nothrow__, __leaf__, __noreturn__ )) {
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178 | abort( false, "%s", "" );
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179 | }
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180 |
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181 | libcfa_public void __cabi_abort( const char fmt[], ... ) __attribute__(( format(printf, 1, 2), __nothrow__, __leaf__, __noreturn__ )) {
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182 | va_list argp;
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183 | va_start( argp, fmt );
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184 | __abort( false, fmt, argp );
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185 | va_end( argp );
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186 | }
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187 |
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188 | libcfa_public void exit( int status ) __attribute__(( __nothrow__, __leaf__, __noreturn__ )) {
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189 | __cabi_libc.exit( status );
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190 | }
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191 | }
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192 |
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193 | // See concurrency/kernel.cfa and concurrency/preemption.cfa for strong definition used in multi-processor mode.
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194 | void __kernel_abort_lock( void ) __attribute__(( __nothrow__, __leaf__, __weak__ )) {}
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195 | void __kernel_abort_msg( char buffer[], int size ) __attribute__(( __nothrow__, __leaf__, __weak__ )) {}
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196 | int __kernel_abort_lastframe( void ) __attribute__(( __nothrow__, __leaf__, __weak__ )) { return 4; }
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197 |
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198 | enum { abort_text_size = 1024 };
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199 | static char abort_text[ abort_text_size ];
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200 |
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201 | static void __cfaabi_backtrace( int start ) {
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202 | enum { Frames = 50, }; // maximum number of stack frames
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203 | int last = __kernel_abort_lastframe(); // skip last N stack frames
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204 |
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205 | void * array[Frames];
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206 | size_t size = backtrace( array, Frames );
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207 | char ** messages = backtrace_symbols( array, size ); // does not demangle names
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208 |
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209 | *index( messages[0], '(' ) = '\0'; // find executable name
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210 | __cfaabi_bits_print_nolock( STDERR_FILENO, "Stack back trace for: %s\n", messages[0]);
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211 |
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212 | for ( unsigned int i = start; i < size - last && messages != 0p; i += 1 ) {
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213 | char * name = 0p, * offset_begin = 0p, * offset_end = 0p;
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214 |
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215 | for ( char * p = messages[i]; *p; p += 1 ) { // find parantheses and +offset
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216 | //__cfaabi_bits_print_nolock( "X %s\n", p);
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217 | if ( *p == '(' ) {
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218 | name = p;
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219 | } else if ( *p == '+' ) {
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220 | offset_begin = p;
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221 | } else if ( *p == ')' ) {
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222 | offset_end = p;
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223 | break;
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224 | }
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225 | }
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226 |
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227 | // if line contains symbol, print it
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228 | int frameNo = i - start;
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229 | if ( name && offset_begin && offset_end && name < offset_begin ) {
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230 | *name++ = '\0'; // delimit strings
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231 | *offset_begin++ = '\0';
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232 | *offset_end++ = '\0';
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233 |
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234 | __cfaabi_bits_print_nolock( STDERR_FILENO, "(%i) %s : %s + %s %s\n", frameNo, messages[i], name, offset_begin, offset_end);
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235 | } else { // otherwise, print the whole line
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236 | __cfaabi_bits_print_nolock( STDERR_FILENO, "(%i) %s\n", frameNo, messages[i] );
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237 | }
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238 | }
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239 | free( messages );
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240 | }
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241 |
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242 | void exit( int status, const char fmt[], ... ) {
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243 | va_list args;
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244 | va_start( args, fmt );
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245 | vfprintf( stderr, fmt, args );
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246 | va_end( args );
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247 | __cabi_libc.exit( status );
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248 | }
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249 |
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250 | static volatile bool __abort_first = 0;
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251 |
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252 | // Cannot forward va_list.
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253 | void __abort( bool signalAbort, const char fmt[], va_list args ) {
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254 | // Multiple threads can come here from multiple paths
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255 | // To make sure this is safe any concurrent/subsequent call to abort is redirected to libc-abort
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256 | bool first = ! __atomic_test_and_set( &__abort_first, __ATOMIC_SEQ_CST);
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257 |
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258 | // Prevent preemption from kicking-in and messing with the abort
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259 | __kernel_abort_lock();
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260 |
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261 | // first to abort ?
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262 | if ( !first ) {
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263 | // We aren't the first to abort just let C handle it
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264 | signal( SIGABRT, SIG_DFL ); // restore default in case we came here through the function.
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265 | __cabi_libc.abort();
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266 | }
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267 |
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268 | int 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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269 | __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
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270 |
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271 | // print the cause of the error
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272 | assert( fmt );
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273 | len = vsnprintf( abort_text, abort_text_size, fmt, args );
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274 | __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
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275 |
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276 | // add optional newline if missing at the end of the format text
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277 | if ( fmt[strlen( fmt ) - 1] != '\n' ) {
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278 | __cfaabi_bits_write( STDERR_FILENO, "\n", 1 );
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279 | } // if
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280 |
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281 | // Give the kernel the chance to add some data in here
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282 | __kernel_abort_msg( abort_text, abort_text_size );
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283 |
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284 | // print stack trace in handler
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285 | __cfaabi_backtrace( signalAbort ? 4 : 2 );
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286 |
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287 | // Finally call abort
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288 | __cabi_libc.abort();
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289 |
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290 | }
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291 |
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292 | void abort( const char fmt[], ... ) {
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293 | va_list args;
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294 | va_start( args, fmt );
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295 | __abort( false, fmt, args );
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296 | // CONTROL NEVER REACHES HERE!
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297 | va_end( args );
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298 | }
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299 |
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300 | void abort( bool signalAbort, const char fmt[], ... ) {
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301 | va_list args;
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302 | va_start( args, fmt );
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303 | __abort( signalAbort, fmt, args );
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304 | // CONTROL NEVER REACHES HERE!
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305 | va_end( args );
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306 | }
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307 |
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308 | void sigHandler_segv( __CFA_SIGPARMS__ ) {
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309 | if ( sfp->si_addr == 0p ) {
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310 | abort( true, "Null pointer (0p) dereference.\n" );
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311 | } else {
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312 | abort( true, "%s at memory location %p.\n"
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313 | "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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314 | (sig == SIGSEGV ? "Segment fault" : "Bus error"), sfp->si_addr );
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315 | }
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316 | }
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317 |
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318 | void sigHandler_ill( __CFA_SIGPARMS__ ) {
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319 | abort( true, "Executing illegal instruction at location %p.\n"
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320 | "Possible cause is stack corruption.\n",
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321 | sfp->si_addr );
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322 | }
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323 |
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324 | void sigHandler_fpe( __CFA_SIGPARMS__ ) {
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325 | const char * msg;
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326 |
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327 | choose( sfp->si_code ) {
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328 | case FPE_INTDIV, FPE_FLTDIV: msg = "divide by zero";
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329 | case FPE_FLTOVF: msg = "overflow";
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330 | case FPE_FLTUND: msg = "underflow";
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331 | case FPE_FLTRES: msg = "inexact result";
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332 | case FPE_FLTINV: msg = "invalid operation";
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333 | default: msg = "unknown";
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334 | } // choose
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335 | abort( true, "Computation error %s at location %p.\n", msg, sfp->si_addr );
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336 | }
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337 |
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338 | void sigHandler_term( __CFA_SIGPARMS__ ) {
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339 | abort( true, "Application interrupted by signal: %s.\n", strsignal( sig ) );
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340 | }
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341 |
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342 | // Local Variables: //
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343 | // mode: c //
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344 | // tab-width: 4 //
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345 | // End: //
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