1 | /*- |
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2 | * Copyright (c) 2006,2008-2011 Joseph Koshy |
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3 | * All rights reserved. |
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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 |
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7 | * are met: |
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8 | * 1. Redistributions of source code must retain the above copyright |
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9 | * notice, this list of conditions and the following disclaimer. |
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10 | * 2. Redistributions in binary form must reproduce the above copyright |
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11 | * notice, this list of conditions and the following disclaimer in the |
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12 | * documentation and/or other materials provided with the distribution. |
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13 | * |
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14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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15 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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16 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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17 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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18 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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19 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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20 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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21 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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22 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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23 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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24 | * SUCH DAMAGE. |
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25 | */ |
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26 | |
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27 | #include <libelf.h> |
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28 | |
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29 | #include "_libelf.h" |
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30 | |
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31 | ELFTC_VCSID("$Id: elf_begin.c 2364 2011-12-28 17:55:25Z jkoshy $"); |
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32 | |
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33 | Elf * |
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34 | elf_begin(int fd, Elf_Cmd c, Elf *a) |
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35 | { |
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36 | Elf *e; |
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37 | |
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38 | e = NULL; |
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39 | |
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40 | if (LIBELF_PRIVATE(version) == EV_NONE) { |
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41 | LIBELF_SET_ERROR(SEQUENCE, 0); |
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42 | return (NULL); |
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43 | } |
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44 | |
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45 | switch (c) { |
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46 | case ELF_C_NULL: |
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47 | return (NULL); |
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48 | |
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49 | case ELF_C_WRITE: |
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50 | /* |
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51 | * The ELF_C_WRITE command is required to ignore the |
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52 | * descriptor passed in. |
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53 | */ |
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54 | a = NULL; |
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55 | break; |
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56 | |
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57 | case ELF_C_RDWR: |
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58 | if (a != NULL) { /* not allowed for ar(1) archives. */ |
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59 | LIBELF_SET_ERROR(ARGUMENT, 0); |
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60 | return (NULL); |
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61 | } |
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62 | /*FALLTHROUGH*/ |
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63 | case ELF_C_READ: |
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64 | /* |
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65 | * Descriptor `a' could be for a regular ELF file, or |
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66 | * for an ar(1) archive. If descriptor `a' was opened |
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67 | * using a valid file descriptor, we need to check if |
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68 | * the passed in `fd' value matches the original one. |
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69 | */ |
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70 | if (a && |
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71 | ((a->e_fd != -1 && a->e_fd != fd) || c != a->e_cmd)) { |
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72 | LIBELF_SET_ERROR(ARGUMENT, 0); |
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73 | return (NULL); |
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74 | } |
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75 | break; |
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76 | |
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77 | default: |
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78 | LIBELF_SET_ERROR(ARGUMENT, 0); |
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79 | return (NULL); |
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80 | |
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81 | } |
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82 | |
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83 | if (a == NULL) |
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84 | e = _libelf_open_object(fd, c, 1); |
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85 | else if (a->e_kind == ELF_K_AR) |
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86 | e = _libelf_ar_open_member(a->e_fd, c, a); |
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87 | else |
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88 | (e = a)->e_activations++; |
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89 | |
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90 | return (e); |
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91 | } |
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