66 lines
1.8 KiB
Bash
66 lines
1.8 KiB
Bash
# mktmp.bash
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# Author: Noah Friedman <friedman@prep.ai.mit.edu>
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# Created: 1993-02-03
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# Last modified: 1993-02-03
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# Public domain
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# Conversion to bash v2 syntax done by Chet Ramey
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# Commentary:
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# Code:
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#:docstring mktmp:
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# Usage: mktmp [template] {createp}
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#
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# Generate a unique filename from TEMPLATE by appending a random number to
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# the end.
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#
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# If optional 2nd arg CREATEP is non-null, file will be created atomically
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# before returning. This is to avoid the race condition that in between
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# the time that the temporary name is returned and the caller uses it,
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# someone else creates the file.
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#:end docstring:
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###;;;autoload
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function mktmp ()
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{
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local template="$1"
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local tmpfile="${template}${RANDOM}"
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local createp="$2"
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local noclobber_status
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case "$-" in
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*C*) noclobber_status=set;;
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esac
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if [ "${createp:+set}" = "set" ]; then
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# Version which creates file atomically through noclobber test.
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set -o noclobber
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(> "${tmpfile}") 2> /dev/null
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while [ $? -ne 0 ] ; do
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# Detect whether file really exists or creation lost because of
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# some other permissions problem. If the latter, we don't want
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# to loop forever.
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if [ ! -e "${tmpfile}" ]; then
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# Trying to create file again creates stderr message.
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echo -n "mktmp: " 1>&2
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> "${tmpfile}"
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return 1
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fi
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tmpfile="${template}${RANDOM}"
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(> "${tmpfile}") 2> /dev/null
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done
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test "${noclobber_status}" != "set" && set +o noclobber
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else
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# Doesn't create file, so it introduces race condition for caller.
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while [ -e "${tmpfile}" ]; do
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tmpfile="${template}${RANDOM}"
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done
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fi
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echo "${tmpfile}"
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}
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provide mktmp
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# mktmp.bash ends here
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