mirror of
git://git.musl-libc.org/musl
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e678fc6f32
the historical (non-standardized) install command is really inappropriate for installing binaries/libraries on a system that utilizes memory-mapped executable files. rather than replacing an existing file atomically, it overwrites the existing file. this can cause running programs to see a partially-modified version of the file, resulting in unpredictable behavior, or SIGBUS. a MAP_COPY mode for mmap would get around this problem, but Linux lacks MAP_COPY. the shell script added with this commit works around the problem by writing temporary files and moving them into place. unlike the historical install utility, it also support a -l option for installing a symbolic link atomically, via the same method.
66 lines
939 B
Bash
Executable File
66 lines
939 B
Bash
Executable File
#!/bin/sh
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#
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# This is an actually-safe install command which installs the new
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# file atomically in the new location, rather than overwriting
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# existing files.
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#
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usage() {
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printf "usage: %s [-D] [-l] [-m mode] src dest\n" "$0" 1>&2
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exit 1
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}
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mkdirp=
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symlink=
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mode=755
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while getopts Dlm: name ; do
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case "$name" in
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D) mkdirp=yes ;;
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l) symlink=yes ;;
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m) mode=$OPTARG ;;
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?) usage ;;
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esac
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done
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shift $(($OPTIND - 1))
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test "$#" -eq 2 || usage
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src=$1
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dst=$2
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tmp="$dst.tmp.$$"
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case "$dst" in
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*/) printf "%s: %s ends in /\n", "$0" "$dst" 1>&2 ; exit 1 ;;
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esac
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set -C
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set -e
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if test "$mkdirp" ; then
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umask 022
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case "$2" in
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*/*) mkdir -p "${dst%/*}" ;;
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esac
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fi
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trap 'rm -f "$tmp"' EXIT INT QUIT TERM HUP
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umask 077
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if test "$symlink" ; then
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ln -s "$1" "$tmp"
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else
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cat < "$1" > "$tmp"
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fi
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mv "$tmp" "$2"
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test -d "$2" && {
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rm -f "$2/$tmp"
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printf "%s: %s is a directory\n" "$0" "$dst" 1>&2
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exit 1
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}
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test "$symlink" || chmod "$mode" "$2"
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exit 0
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