1 /* fileline.c -- Get file and line number information in a backtrace. 2 Copyright (C) 2012-2016 Free Software Foundation, Inc. 3 Written by Ian Lance Taylor, Google. 4 5 Redistribution and use in source and binary forms, with or without 6 modification, are permitted provided that the following conditions are 7 met: 8 9 (1) Redistributions of source code must retain the above copyright 10 notice, this list of conditions and the following disclaimer. 11 12 (2) Redistributions in binary form must reproduce the above copyright 13 notice, this list of conditions and the following disclaimer in 14 the documentation and/or other materials provided with the 15 distribution. 16 17 (3) The name of the author may not be used to 18 endorse or promote products derived from this software without 19 specific prior written permission. 20 21 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 23 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 24 DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 25 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 26 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 27 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 29 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 30 IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 POSSIBILITY OF SUCH DAMAGE. */ 32 33 #include "config.h" 34 35 #include <sys/types.h> 36 #include <sys/stat.h> 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <stdlib.h> 40 41 #include "backtrace.h" 42 #include "internal.h" 43 44 #ifndef HAVE_GETEXECNAME 45 #define getexecname() NULL 46 #endif 47 48 /* Initialize the fileline information from the executable. Returns 1 49 on success, 0 on failure. */ 50 51 static int 52 fileline_initialize (struct backtrace_state *state, 53 backtrace_error_callback error_callback, void *data) 54 { 55 int failed; 56 fileline fileline_fn; 57 int pass; 58 int called_error_callback; 59 int descriptor; 60 61 if (!state->threaded) 62 failed = state->fileline_initialization_failed; 63 else 64 failed = backtrace_atomic_load_int (&state->fileline_initialization_failed); 65 66 if (failed) 67 { 68 error_callback (data, "failed to read executable information", -1); 69 return 0; 70 } 71 72 if (!state->threaded) 73 fileline_fn = state->fileline_fn; 74 else 75 fileline_fn = backtrace_atomic_load_pointer (&state->fileline_fn); 76 if (fileline_fn != NULL) 77 return 1; 78 79 /* We have not initialized the information. Do it now. */ 80 81 descriptor = -1; 82 called_error_callback = 0; 83 for (pass = 0; pass < 4; ++pass) 84 { 85 const char *filename; 86 int does_not_exist; 87 88 switch (pass) 89 { 90 case 0: 91 filename = state->filename; 92 break; 93 case 1: 94 filename = getexecname (); 95 break; 96 case 2: 97 filename = "/proc/self/exe"; 98 break; 99 case 3: 100 filename = "/proc/curproc/file"; 101 break; 102 default: 103 abort (); 104 } 105 106 if (filename == NULL) 107 continue; 108 109 descriptor = backtrace_open (filename, error_callback, data, 110 &does_not_exist); 111 if (descriptor < 0 && !does_not_exist) 112 { 113 called_error_callback = 1; 114 break; 115 } 116 if (descriptor >= 0) 117 break; 118 } 119 120 if (descriptor < 0) 121 { 122 if (!called_error_callback) 123 { 124 if (state->filename != NULL) 125 error_callback (data, state->filename, ENOENT); 126 else 127 error_callback (data, 128 "libbacktrace could not find executable to open", 129 0); 130 } 131 failed = 1; 132 } 133 134 if (!failed) 135 { 136 if (!backtrace_initialize (state, descriptor, error_callback, data, 137 &fileline_fn)) 138 failed = 1; 139 } 140 141 if (failed) 142 { 143 if (!state->threaded) 144 state->fileline_initialization_failed = 1; 145 else 146 backtrace_atomic_store_int (&state->fileline_initialization_failed, 1); 147 return 0; 148 } 149 150 if (!state->threaded) 151 state->fileline_fn = fileline_fn; 152 else 153 { 154 backtrace_atomic_store_pointer (&state->fileline_fn, fileline_fn); 155 156 /* Note that if two threads initialize at once, one of the data 157 sets may be leaked. */ 158 } 159 160 return 1; 161 } 162 163 /* Given a PC, find the file name, line number, and function name. */ 164 165 int 166 backtrace_pcinfo (struct backtrace_state *state, uintptr_t pc, 167 backtrace_full_callback callback, 168 backtrace_error_callback error_callback, void *data) 169 { 170 if (!fileline_initialize (state, error_callback, data)) 171 return 0; 172 173 if (state->fileline_initialization_failed) 174 return 0; 175 176 return state->fileline_fn (state, pc, callback, error_callback, data); 177 } 178 179 /* Given a PC, find the symbol for it, and its value. */ 180 181 int 182 backtrace_syminfo (struct backtrace_state *state, uintptr_t pc, 183 backtrace_syminfo_callback callback, 184 backtrace_error_callback error_callback, void *data) 185 { 186 if (!fileline_initialize (state, error_callback, data)) 187 return 0; 188 189 if (state->fileline_initialization_failed) 190 return 0; 191 192 state->syminfo_fn (state, pc, callback, error_callback, data); 193 return 1; 194 } 195