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1 /* posix.c -- POSIX file I/O routines for the backtrace library.
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2 Copyright (C) 2012-2020 Free Software Foundation, Inc.
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3 Written by Ian Lance Taylor, Google.
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4
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5 Redistribution and use in source and binary forms, with or without
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6 modification, are permitted provided that the following conditions are
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7 met:
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8
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9 (1) Redistributions of source code must retain the above copyright
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10 notice, this list of conditions and the following disclaimer.
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11
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12 (2) Redistributions in binary form must reproduce the above copyright
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13 notice, this list of conditions and the following disclaimer in
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14 the documentation and/or other materials provided with the
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15 distribution.
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16
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17 (3) The name of the author may not be used to
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18 endorse or promote products derived from this software without
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19 specific prior written permission.
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20
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21 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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22 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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23 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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24 DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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25 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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26 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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27 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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28 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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29 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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30 IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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31 POSSIBILITY OF SUCH DAMAGE. */
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32
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33 #include "config.h"
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34
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35 #include <errno.h>
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36 #include <sys/types.h>
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37 #include <sys/stat.h>
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38 #include <fcntl.h>
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39 #include <unistd.h>
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40
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41 #include "backtrace.h"
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42 #include "internal.h"
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43
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44 #ifndef O_BINARY
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45 #define O_BINARY 0
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46 #endif
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47
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48 #ifndef O_CLOEXEC
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49 #define O_CLOEXEC 0
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50 #endif
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51
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52 #ifndef FD_CLOEXEC
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53 #define FD_CLOEXEC 1
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54 #endif
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55
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56 /* Open a file for reading. */
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57
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58 int
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59 backtrace_open (const char *filename, backtrace_error_callback error_callback,
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60 void *data, int *does_not_exist)
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61 {
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62 int descriptor;
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63
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64 if (does_not_exist != NULL)
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65 *does_not_exist = 0;
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66
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67 descriptor = open (filename, (int) (O_RDONLY | O_BINARY | O_CLOEXEC));
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68 if (descriptor < 0)
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69 {
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70 if (does_not_exist != NULL && errno == ENOENT)
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71 *does_not_exist = 1;
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72 else
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73 error_callback (data, filename, errno);
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74 return -1;
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75 }
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76
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77 #ifdef HAVE_FCNTL
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78 /* Set FD_CLOEXEC just in case the kernel does not support
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79 O_CLOEXEC. It doesn't matter if this fails for some reason.
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80 FIXME: At some point it should be safe to only do this if
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81 O_CLOEXEC == 0. */
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82 fcntl (descriptor, F_SETFD, FD_CLOEXEC);
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83 #endif
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84
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85 return descriptor;
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86 }
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87
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88 /* Close DESCRIPTOR. */
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89
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90 int
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91 backtrace_close (int descriptor, backtrace_error_callback error_callback,
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92 void *data)
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93 {
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94 if (close (descriptor) < 0)
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95 {
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96 error_callback (data, "close", errno);
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97 return 0;
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98 }
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99 return 1;
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100 }
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