[5accd22] | 1 | <?xml version="1.0" encoding="ISO-8859-1"?> |
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[aa18ac0] | 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
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| 3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ |
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[5accd22] | 4 | <!ENTITY % general-entities SYSTEM "../../general.ent"> |
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| 5 | %general-entities; |
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| 6 | ]> |
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| 7 | |
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| 8 | <sect1 id="ch-system-multiarch-wrapper" role="wrap"> |
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| 9 | <?dbhtml filename="multiarch_wrapper.html"?> |
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| 10 | |
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[72ed305] | 11 | <title>Creating a Multiarch Wrapper</title> |
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[5accd22] | 12 | |
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| 13 | <indexterm zone="ch-system-multiarch-wrapper"> |
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[8ab693a] | 14 | <primary sortas="a-Multiarch Wrapper">Multiarch Wrapper</primary> |
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[5accd22] | 15 | </indexterm> |
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| 16 | |
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| 17 | <sect2 role="package"> |
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| 18 | <title/> |
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| 19 | |
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| 20 | <para>The Multiarch Wrapper is used to wrap certain binaries that have |
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| 21 | hardcoded paths to libraries or are architecture specific.</para> |
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| 22 | |
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| 23 | </sect2> |
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| 24 | |
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| 25 | <sect2 role="installation"> |
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| 26 | <title>Installation of The Multiarch Wrapper</title> |
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| 27 | |
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| 28 | <para os="a">Create the source file:</para> |
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| 29 | |
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| 30 | <screen os="b"><userinput>cat > multiarch_wrapper.c << "EOF" |
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[d4a75ad] | 31 | #define _GNU_SOURCE |
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| 32 | |
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[5accd22] | 33 | #include <errno.h> |
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[d4a75ad] | 34 | #include <stdio.h> |
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| 35 | #include <stdlib.h> |
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| 36 | #include <sys/types.h> |
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| 37 | #include <sys/wait.h> |
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| 38 | #include <unistd.h> |
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[5accd22] | 39 | |
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[d4a75ad] | 40 | #ifndef DEF_SUFFIX |
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| 41 | # define DEF_SUFFIX "64" |
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[5accd22] | 42 | #endif |
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| 43 | |
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[5fb43ca] | 44 | int main(int argc, char **argv) |
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[5accd22] | 45 | { |
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[5fb43ca] | 46 | char *filename; |
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[d4a75ad] | 47 | char *suffix; |
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| 48 | |
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| 49 | if(!(suffix = getenv("USE_ARCH"))) |
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| 50 | if(!(suffix = getenv("BUILDENV"))) |
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| 51 | suffix = DEF_SUFFIX; |
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| 52 | |
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| 53 | if (asprintf(&filename, "%s-%s", argv[0], suffix) < 0) { |
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| 54 | perror(argv[0]); |
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| 55 | return -1; |
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| 56 | } |
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| 57 | |
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| 58 | int status = EXIT_FAILURE; |
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| 59 | pid_t pid = fork(); |
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| 60 | |
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| 61 | if (pid == 0) { |
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| 62 | execvp(filename, argv); |
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| 63 | perror(filename); |
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| 64 | } else if (pid < 0) { |
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[7949a91] | 65 | perror(argv[0]); |
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[d4a75ad] | 66 | } else { |
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| 67 | if (waitpid(pid, &status, 0) != pid) { |
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| 68 | status = EXIT_FAILURE; |
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[7949a91] | 69 | perror(argv[0]); |
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| 70 | } else { |
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| 71 | status = WEXITSTATUS(status); |
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[d4a75ad] | 72 | } |
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| 73 | } |
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| 74 | |
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[5accd22] | 75 | free(filename); |
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[d4a75ad] | 76 | |
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| 77 | return status; |
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[5accd22] | 78 | } |
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[d4a75ad] | 79 | |
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[5accd22] | 80 | EOF</userinput></screen> |
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| 81 | |
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| 82 | <para os="c">Compile and Install the Multiarch Wrapper:</para> |
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| 83 | |
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| 84 | <screen os="d"><userinput>gcc ${BUILD64} multiarch_wrapper.c -o /usr/bin/multiarch_wrapper</userinput></screen> |
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| 85 | |
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| 86 | <para os="e">This multiarch wrapper is going to be used later on in the book |
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[a7fa075] | 87 | with Perl. It will also be very useful outside of the base CLFS system.</para> |
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[5accd22] | 88 | |
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[a7fa075] | 89 | <para os="f">Create a testcase:</para> |
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[5accd22] | 90 | |
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| 91 | <screen os="g"><userinput>echo 'echo "32bit Version"' > test-32 |
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| 92 | echo 'echo "64bit Version"' > test-64 |
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| 93 | chmod 755 test-32 test-64 |
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| 94 | ln -sv /usr/bin/multiarch_wrapper test</userinput></screen> |
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| 95 | |
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[a7fa075] | 96 | <para os="h">Test the wrapper:</para> |
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[5accd22] | 97 | |
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| 98 | <screen os="i"><userinput>USE_ARCH=32 ./test |
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| 99 | USE_ARCH=64 ./test</userinput></screen> |
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| 100 | |
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| 101 | <para os="j">The output of the above command should be:</para> |
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| 102 | |
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[32c37aa8] | 103 | <screen os="k" role="nodump"><userinput>32bit Version |
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[5accd22] | 104 | 64bit Version</userinput></screen> |
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| 105 | |
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[bf996fc] | 106 | <para os="l">Remove the testcase source, binaries, and link:</para> |
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[91044db] | 107 | |
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[bf996fc] | 108 | <screen os="m"><userinput>rm -v multiarch_wrapper.c test{,-32,-64}</userinput></screen> |
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[91044db] | 109 | |
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[5accd22] | 110 | </sect2> |
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| 111 | |
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| 112 | <sect2 id="contents-multiarch-wrapper" role="content"> |
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| 113 | <title>Contents of The Multiarch Wrapper</title> |
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| 114 | |
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| 115 | <segmentedlist> |
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| 116 | <segtitle>Installed programs</segtitle> |
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| 117 | |
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| 118 | <seglistitem> |
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| 119 | <seg>multiarch_wrapper</seg> |
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| 120 | </seglistitem> |
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| 121 | </segmentedlist> |
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| 122 | |
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| 123 | <variablelist> |
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| 124 | <bridgehead renderas="sect3">Short Descriptions</bridgehead> |
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| 125 | <?dbfo list-presentation="list"?> |
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| 126 | <?dbhtml list-presentation="table"?> |
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| 127 | |
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| 128 | <varlistentry id="multiarch_wrapper"> |
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| 129 | <term><command>multiarch_wrapper</command></term> |
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| 130 | <listitem> |
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| 131 | <para>Will execute a different program based on the |
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| 132 | <envar>USE_ARCH</envar> variable. The <envar>USE_ARCH</envar> |
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| 133 | variable will be the suffix of the executed program.</para> |
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| 134 | <indexterm zone="ch-system-multiarch-wrapper multiarch_wrapper"> |
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| 135 | <primary sortas="b-multiarch_wrapper">multiarch_wrapper</primary> |
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| 136 | </indexterm> |
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| 137 | </listitem> |
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| 138 | </varlistentry> |
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| 139 | |
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| 140 | </variablelist> |
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| 141 | |
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| 142 | </sect2> |
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| 143 | |
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| 144 | </sect1> |
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