| 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 Mar 27 21:09:03 2023
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| 13 | // Update Count : 196
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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 <execinfo.h> // backtrace, messages
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| 21 | }
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| 22 |
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| 23 | #include "bits/defs.hfa"
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| 24 | #include "bits/signal.hfa" // sigHandler_?
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| 25 | #include "startup.hfa" // STARTUP_PRIORITY_CORE
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| 26 | #include <assert.h>
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| 27 |
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| 28 | //=============================================================================================
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| 29 | // Interposing helpers
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| 30 | //=============================================================================================
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| 31 |
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| 32 | static void preload_libgcc(void) {
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| 33 | dlopen( "libgcc_s.so.1", RTLD_NOW );
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| 34 | if ( const char * error = dlerror() ) abort( "interpose_symbol : internal error pre-loading libgcc, %s\n", error );
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| 35 | }
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| 36 |
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| 37 | typedef void (* generic_fptr_t)(void);
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| 38 |
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| 39 | static generic_fptr_t do_interpose_symbol( void * library, const char symbol[], const char version[] ) {
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| 40 | union { generic_fptr_t fptr; void * ptr; } originalFunc;
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| 41 |
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| 42 | #if defined( _GNU_SOURCE )
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| 43 | if ( version ) {
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| 44 | originalFunc.ptr = dlvsym( library, symbol, version );
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| 45 | } else {
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| 46 | originalFunc.ptr = dlsym( library, symbol );
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| 47 | } // if
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| 48 | #else
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| 49 | originalFunc.ptr = dlsym( library, symbol );
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| 50 | #endif // _GNU_SOURCE
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| 51 |
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| 52 | if ( ! originalFunc.ptr ) { // == nullptr
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| 53 | abort( "interpose_symbol : internal error, %s\n", dlerror() );
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| 54 | } // if
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| 55 | return originalFunc.fptr;
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| 56 | }
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| 57 |
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| 58 | static generic_fptr_t interpose_symbol( const char symbol[], const char version[] ) {
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| 59 | void * library;
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| 60 |
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| 61 | #if defined( RTLD_NEXT )
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| 62 | library = RTLD_NEXT;
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| 63 | #else
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| 64 | // missing RTLD_NEXT => must hard-code library name, assuming libstdc++
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| 65 | library = dlopen( "libc.so.6", RTLD_LAZY );
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| 66 | if ( ! library ) { // == nullptr
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| 67 | abort( "interpose_symbol : failed to open libc, %s\n", dlerror() );
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| 68 | } // if
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| 69 | #endif // RTLD_NEXT
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| 70 |
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| 71 | return do_interpose_symbol( library, symbol, version );
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| 72 | }
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| 73 |
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| 74 | #define INTERPOSE_LIBC( x, ver ) __cabi_libc.x = (typeof(__cabi_libc.x))interpose_symbol( #x, ver )
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| 75 |
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| 76 | //=============================================================================================
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| 77 | // Interposition Startup logic
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| 78 | //=============================================================================================
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| 79 |
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| 80 | static void sigHandler_segv( __CFA_SIGPARMS__ );
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| 81 | static void sigHandler_ill ( __CFA_SIGPARMS__ );
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| 82 | static void sigHandler_fpe ( __CFA_SIGPARMS__ );
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| 83 | static void sigHandler_abrt( __CFA_SIGPARMS__ );
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| 84 | static void sigHandler_term( __CFA_SIGPARMS__ );
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| 85 |
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| 86 | static struct {
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| 87 | void (* exit)( int ) __attribute__(( __noreturn__ ));
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| 88 | void (* abort)( void ) __attribute__(( __noreturn__ ));
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| 89 | } __cabi_libc;
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| 90 |
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| 91 | libcfa_public int cfa_main_returned;
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| 92 |
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| 93 | extern "C" {
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| 94 | void __cfathreadabi_interpose_startup( generic_fptr_t (*do_interpose_symbol)( void * library, const char symbol[], const char version[] ) ) __attribute__((weak));
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| 95 | void __cfaabi_interpose_startup( void ) {
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| 96 | const char *version = 0p;
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| 97 | cfa_main_returned = 0;
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| 98 |
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| 99 | preload_libgcc();
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| 100 |
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| 101 | #pragma GCC diagnostic push
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| 102 | #pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
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| 103 | INTERPOSE_LIBC( abort, version );
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| 104 | INTERPOSE_LIBC( exit , version );
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| 105 | #pragma GCC diagnostic pop
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| 106 |
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| 107 | if(__cfathreadabi_interpose_startup) __cfathreadabi_interpose_startup( do_interpose_symbol );
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| 108 |
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| 109 | // SKULLDUGGERY: In Ubuntu 22.04, someone augmented signal.h to allow SIGSTKSZ to be "sysconf(_SC_SIGSTKSZ)" in
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| 110 | // 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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| 111 | // use sigstack.h rather than sigstksz.h. (I'm not happy.) By undefining _GNU_SOURCE before signal.h and
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| 112 | // redefining it afterwards, you can get 8192, but then nothing works correctly inside of signal.h without
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| 113 | // _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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| 114 | // Basically something is wrong with features.h and its use in signal.h.
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| 115 |
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| 116 | #undef SIGSTKSZ
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| 117 | #define SIGSTKSZ 8192
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| 118 |
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| 119 | // As a precaution (and necessity), errors that result in termination are delivered on a separate stack because
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| 120 | // task stacks might be very small (4K) and the signal delivery corrupts memory to the point that a clean
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| 121 | // shutdown is impossible. Also, when a stack overflow encounters the non-accessible sentinel page (debug only)
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| 122 | // and generates a segment fault, the signal cannot be delivered on the sentinel page. Finally, calls to abort
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| 123 | // print a stack trace that uses substantial stack space.
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| 124 |
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| 125 | #define MINSTKSZ SIGSTKSZ * 8
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| 126 | static char stack[MINSTKSZ] __attribute__(( aligned (16) ));
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| 127 | static stack_t ss;
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| 128 |
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| 129 | ss.ss_sp = stack;
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| 130 | ss.ss_size = MINSTKSZ;
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| 131 | ss.ss_flags = 0;
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| 132 | if ( sigaltstack( &ss, 0p ) == -1 ) {
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| 133 | abort( "__cfaabi_interpose_startup : internal error, sigaltstack error(%d) %s.", errno, strerror( errno ) );
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| 134 | } // if
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| 135 |
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| 136 | // Failure handler
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| 137 | // internal errors
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| 138 | __cfaabi_sigaction( SIGSEGV, sigHandler_segv, SA_SIGINFO | SA_ONSTACK ); // Invalid memory reference (default: Core)
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| 139 | __cfaabi_sigaction( SIGBUS , sigHandler_segv, SA_SIGINFO | SA_ONSTACK ); // Bus error, bad memory access (default: Core)
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| 140 | __cfaabi_sigaction( SIGILL , sigHandler_ill , SA_SIGINFO | SA_ONSTACK ); // Illegal Instruction (default: Core)
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| 141 | __cfaabi_sigaction( SIGFPE , sigHandler_fpe , SA_SIGINFO | SA_ONSTACK ); // Floating-point exception (default: Core)
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| 142 |
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| 143 | // handlers to outside errors
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| 144 | // reset in-case they insist and send it over and over
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| 145 | __cfaabi_sigaction( SIGTERM, sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Termination signal (default: Term)
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| 146 | __cfaabi_sigaction( SIGINT , sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Interrupt from keyboard (default: Term)
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| 147 | __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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| 148 | __cfaabi_sigaction( SIGQUIT, sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Quit from keyboard (default: Core)
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| 149 | __cfaabi_sigaction( SIGABRT, sigHandler_term, SA_SIGINFO | SA_ONSTACK | SA_RESETHAND ); // Abort signal from abort(3) (default: Core)
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| 150 | }
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| 151 | }
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| 152 |
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| 153 | //=============================================================================================
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| 154 | // Terminating Signals logic
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| 155 | //=============================================================================================
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| 156 |
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| 157 | // Forward declare abort after the __typeof__ call to avoid ambiguities
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| 158 | libcfa_public void exit( int status, const char fmt[], ... ) __attribute__(( format(printf, 2, 3), __nothrow__, __leaf__, __noreturn__ ));
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| 159 | libcfa_public void abort( const char fmt[], ... ) __attribute__(( format(printf, 1, 2), __nothrow__, __leaf__, __noreturn__ ));
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| 160 | libcfa_public void abort( bool signalAbort, const char fmt[], ... ) __attribute__(( format(printf, 2, 3), __nothrow__, __leaf__, __noreturn__ ));
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| 161 | libcfa_public void __abort( bool signalAbort, const char fmt[], va_list args ) __attribute__(( __nothrow__, __leaf__, __noreturn__ ));
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| 162 |
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| 163 | extern "C" {
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| 164 | libcfa_public void abort( void ) __attribute__(( __nothrow__, __leaf__, __noreturn__ )) {
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| 165 | abort( false, "%s", "" );
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| 166 | }
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| 167 |
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| 168 | libcfa_public void __cabi_abort( const char fmt[], ... ) __attribute__(( format(printf, 1, 2), __nothrow__, __leaf__, __noreturn__ )) {
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| 169 | va_list argp;
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| 170 | va_start( argp, fmt );
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| 171 | __abort( false, fmt, argp );
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| 172 | va_end( argp );
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| 173 | }
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| 174 |
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| 175 | libcfa_public void exit( int status ) __attribute__(( __nothrow__, __leaf__, __noreturn__ )) {
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| 176 | __cabi_libc.exit( status );
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| 177 | }
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| 178 | }
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| 179 |
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| 180 | // See concurrency/kernel.cfa and concurrency/preemption.cfa for strong definition used in multi-processor mode.
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| 181 | void __kernel_abort_lock( void ) __attribute__(( __nothrow__, __leaf__, __weak__ )) {}
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| 182 | void __kernel_abort_msg( char buffer[], int size ) __attribute__(( __nothrow__, __leaf__, __weak__ )) {}
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| 183 | int __kernel_abort_lastframe( void ) __attribute__(( __nothrow__, __leaf__, __weak__ )) { return 4; }
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| 184 |
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| 185 | enum { abort_text_size = 1024 };
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| 186 | static char abort_text[ abort_text_size ];
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| 187 |
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| 188 | static void __cfaabi_backtrace( int start ) {
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| 189 | enum { Frames = 50, }; // maximum number of stack frames
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| 190 | int last = __kernel_abort_lastframe(); // skip last N stack frames
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| 191 |
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| 192 | void * array[Frames];
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| 193 | size_t size = backtrace( array, Frames );
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| 194 | char ** messages = backtrace_symbols( array, size ); // does not demangle names
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| 195 |
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| 196 | *index( messages[0], '(' ) = '\0'; // find executable name
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| 197 | __cfaabi_bits_print_nolock( STDERR_FILENO, "Stack back trace for: %s\n", messages[0]);
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| 198 |
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| 199 | for ( unsigned int i = start; i < size - last && messages != 0p; i += 1 ) {
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| 200 | char * name = 0p, * offset_begin = 0p, * offset_end = 0p;
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| 201 |
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| 202 | for ( char * p = messages[i]; *p; p += 1 ) { // find parantheses and +offset
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| 203 | //__cfaabi_bits_print_nolock( "X %s\n", p);
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| 204 | if ( *p == '(' ) {
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| 205 | name = p;
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| 206 | } else if ( *p == '+' ) {
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| 207 | offset_begin = p;
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| 208 | } else if ( *p == ')' ) {
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| 209 | offset_end = p;
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| 210 | break;
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| 211 | }
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| 212 | }
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| 213 |
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| 214 | // if line contains symbol, print it
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| 215 | int frameNo = i - start;
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| 216 | if ( name && offset_begin && offset_end && name < offset_begin ) {
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| 217 | *name++ = '\0'; // delimit strings
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| 218 | *offset_begin++ = '\0';
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| 219 | *offset_end++ = '\0';
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| 220 |
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| 221 | __cfaabi_bits_print_nolock( STDERR_FILENO, "(%i) %s : %s + %s %s\n", frameNo, messages[i], name, offset_begin, offset_end);
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| 222 | } else { // otherwise, print the whole line
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| 223 | __cfaabi_bits_print_nolock( STDERR_FILENO, "(%i) %s\n", frameNo, messages[i] );
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| 224 | }
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| 225 | }
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| 226 | free( messages );
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| 227 | }
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| 228 |
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| 229 | void exit( int status, const char fmt[], ... ) {
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| 230 | va_list args;
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| 231 | va_start( args, fmt );
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| 232 | vfprintf( stderr, fmt, args );
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| 233 | va_end( args );
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| 234 | __cabi_libc.exit( status );
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| 235 | }
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| 236 |
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| 237 | static volatile bool __abort_first = 0;
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| 238 |
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| 239 | // Cannot forward va_list.
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| 240 | void __abort( bool signalAbort, const char fmt[], va_list args ) {
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| 241 | // Multiple threads can come here from multiple paths
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| 242 | // To make sure this is safe any concurrent/subsequent call to abort is redirected to libc-abort
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| 243 | bool first = ! __atomic_test_and_set( &__abort_first, __ATOMIC_SEQ_CST);
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| 244 |
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| 245 | // Prevent preemption from kicking-in and messing with the abort
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| 246 | __kernel_abort_lock();
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| 247 |
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| 248 | // first to abort ?
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| 249 | if ( !first ) {
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| 250 | // We aren't the first to abort just let C handle it
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| 251 | signal( SIGABRT, SIG_DFL ); // restore default in case we came here through the function.
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| 252 | __cabi_libc.abort();
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| 253 | }
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| 254 |
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| 255 | 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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| 256 | __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
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| 257 |
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| 258 | // print the cause of the error
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| 259 | assert( fmt );
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| 260 | len = vsnprintf( abort_text, abort_text_size, fmt, args );
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| 261 | __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
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| 262 |
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| 263 | // add optional newline if missing at the end of the format text
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| 264 | if ( fmt[strlen( fmt ) - 1] != '\n' ) {
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| 265 | __cfaabi_bits_write( STDERR_FILENO, "\n", 1 );
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| 266 | } // if
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| 267 |
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| 268 | // Give the kernel the chance to add some data in here
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| 269 | __kernel_abort_msg( abort_text, abort_text_size );
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| 270 |
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| 271 | // print stack trace in handler
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| 272 | __cfaabi_backtrace( signalAbort ? 4 : 2 );
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| 273 |
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| 274 | // Finally call abort
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| 275 | __cabi_libc.abort();
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| 276 |
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| 277 | }
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| 278 |
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| 279 | void abort( const char fmt[], ... ) {
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| 280 | va_list args;
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| 281 | va_start( args, fmt );
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| 282 | __abort( false, fmt, args );
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| 283 | // CONTROL NEVER REACHES HERE!
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| 284 | va_end( args );
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| 285 | }
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| 286 |
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| 287 | void abort( bool signalAbort, const char fmt[], ... ) {
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| 288 | va_list args;
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| 289 | va_start( args, fmt );
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| 290 | __abort( signalAbort, fmt, args );
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| 291 | // CONTROL NEVER REACHES HERE!
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| 292 | va_end( args );
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| 293 | }
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| 294 |
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| 295 | void sigHandler_segv( __CFA_SIGPARMS__ ) {
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| 296 | if ( sfp->si_addr == 0p ) {
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| 297 | abort( true, "Null pointer (0p) dereference.\n" );
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| 298 | } else {
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| 299 | abort( true, "%s at memory location %p.\n"
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| 300 | "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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| 301 | (sig == SIGSEGV ? "Segment fault" : "Bus error"), sfp->si_addr );
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| 302 | }
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| 303 | }
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| 304 |
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| 305 | void sigHandler_ill( __CFA_SIGPARMS__ ) {
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| 306 | abort( true, "Executing illegal instruction at location %p.\n"
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| 307 | "Possible cause is stack corruption.\n",
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| 308 | sfp->si_addr );
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| 309 | }
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| 310 |
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| 311 | void sigHandler_fpe( __CFA_SIGPARMS__ ) {
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| 312 | const char * msg;
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| 313 |
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| 314 | choose( sfp->si_code ) {
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| 315 | case FPE_INTDIV, FPE_FLTDIV: msg = "divide by zero";
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| 316 | case FPE_FLTOVF: msg = "overflow";
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| 317 | case FPE_FLTUND: msg = "underflow";
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| 318 | case FPE_FLTRES: msg = "inexact result";
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| 319 | case FPE_FLTINV: msg = "invalid operation";
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| 320 | default: msg = "unknown";
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| 321 | } // choose
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| 322 | abort( true, "Computation error %s at location %p.\n", msg, sfp->si_addr );
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| 323 | }
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| 324 |
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| 325 | void sigHandler_term( __CFA_SIGPARMS__ ) {
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| 326 | abort( true, "Application interrupted by signal: %s.\n", strsignal( sig ) );
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| 327 | }
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| 328 |
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| 329 | // Local Variables: //
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| 330 | // mode: c //
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| 331 | // tab-width: 4 //
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| 332 | // End: //
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