1 /* posix.c -- POSIX file I/O routines for the backtrace library. 2 Copyright (C) 2012-2024 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 <errno.h> 36 #include <sys/types.h> 37 #include <sys/stat.h> 38 #include <fcntl.h> 39 #include <unistd.h> 40 41 #include "backtrace.h" 42 #include "internal.h" 43 44 #ifndef O_BINARY 45 #define O_BINARY 0 46 #endif 47 48 #ifndef O_CLOEXEC 49 #define O_CLOEXEC 0 50 #endif 51 52 #ifndef FD_CLOEXEC 53 #define FD_CLOEXEC 1 54 #endif 55 56 /* Open a file for reading. */ 57 58 int 59 backtrace_open (const char *filename, backtrace_error_callback error_callback, 60 void *data, int *does_not_exist) 61 { 62 int descriptor; 63 64 if (does_not_exist != NULL) 65 *does_not_exist = 0; 66 67 descriptor = open (filename, (int) (O_RDONLY | O_BINARY | O_CLOEXEC)); 68 if (descriptor < 0) 69 { 70 /* If DOES_NOT_EXIST is not NULL, then don't call ERROR_CALLBACK 71 if the file does not exist. We treat lacking permission to 72 open the file as the file not existing; this case arises when 73 running the libgo syscall package tests as root. */ 74 if (does_not_exist != NULL && (errno == ENOENT || errno == EACCES)) 75 *does_not_exist = 1; 76 else 77 error_callback (data, filename, errno); 78 return -1; 79 } 80 81 #ifdef HAVE_FCNTL 82 /* Set FD_CLOEXEC just in case the kernel does not support 83 O_CLOEXEC. It doesn't matter if this fails for some reason. 84 FIXME: At some point it should be safe to only do this if 85 O_CLOEXEC == 0. */ 86 fcntl (descriptor, F_SETFD, FD_CLOEXEC); 87 #endif 88 89 return descriptor; 90 } 91 92 /* Close DESCRIPTOR. */ 93 94 int 95 backtrace_close (int descriptor, backtrace_error_callback error_callback, 96 void *data) 97 { 98 if (close (descriptor) < 0) 99 { 100 error_callback (data, "close", errno); 101 return 0; 102 } 103 return 1; 104 } 105