1 # Check how to create a tarball. -*- Autoconf -*-
3 # Copyright (C) 2004-2018 Free Software Foundation, Inc.
5 # This file is free software; the Free Software Foundation
6 # gives unlimited permission to copy and/or distribute it,
7 # with or without modifications, as long as this notice is preserved.
10 # --------------------
11 # Check how to create a tarball in format FORMAT.
12 # FORMAT should be one of 'v7', 'ustar', or 'pax'.
14 # Substitute a variable $(am__tar) that is a command
15 # writing to stdout a FORMAT-tarball containing the directory
17 # tardir=directory && $(am__tar) > result.tar
19 # Substitute a variable $(am__untar) that extract such
20 # a tarball read from stdin.
21 # $(am__untar) < result.tar
23 AC_DEFUN([_AM_PROG_TAR],
24 [# Always define AMTAR for backward compatibility. Yes, it's still used
25 # in the wild :-( We should find a proper way to deprecate it ...
26 AC_SUBST([AMTAR], ['$${TAR-tar}'])
28 # We'll loop over all known methods to create a tar archive until one works.
29 _am_tools='gnutar m4_if([$1], [ustar], [plaintar]) pax cpio none'
32 [am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'],
36 [# The POSIX 1988 'ustar' format is defined with fixed-size fields.
37 # There is notably a 21 bits limit for the UID and the GID. In fact,
38 # the 'pax' utility can hang on bigger UID/GID (see automake bug#8343
40 am_max_uid=2097151 # 2^21 - 1
41 am_max_gid=$am_max_uid
42 # The $UID and $GID variables are not portable, so we need to resort
43 # to the POSIX-mandated id(1) utility. Errors in the 'id' calls
44 # below are definitely unexpected, so allow the users to see them
45 # (that is, avoid stderr redirection).
46 am_uid=`id -u || echo unknown`
47 am_gid=`id -g || echo unknown`
48 AC_MSG_CHECKING([whether UID '$am_uid' is supported by ustar format])
49 if test $am_uid -le $am_max_uid; then
55 AC_MSG_CHECKING([whether GID '$am_gid' is supported by ustar format])
56 if test $am_gid -le $am_max_gid; then
66 [m4_fatal([Unknown tar format])])
68 AC_MSG_CHECKING([how to create a $1 tar archive])
70 # Go ahead even if we have the value already cached. We do so because we
71 # need to set the values for the 'am__tar' and 'am__untar' variables.
72 _am_tools=${am_cv_prog_tar_$1-$_am_tools}
74 for _am_tool in $_am_tools; do
77 for _am_tar in tar gnutar gtar; do
78 AM_RUN_LOG([$_am_tar --version]) && break
80 am__tar="$_am_tar --hard-dereference --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$$tardir"'
81 am__tar_="$_am_tar --hard-dereference --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$tardir"'
82 am__untar="$_am_tar -xf -"
85 # Must skip GNU tar: if it does not support --format= it doesn't create
86 # ustar tarball either.
87 (tar --version) >/dev/null 2>&1 && continue
88 am__tar='tar chf --hard-dereference - "$$tardir"'
89 am__tar_='tar chf --hard-dereference - "$tardir"'
93 am__tar='pax -L -x $1 -w "$$tardir"'
94 am__tar_='pax -L -x $1 -w "$tardir"'
98 am__tar='find "$$tardir" -print | cpio -o -H $1 -L'
99 am__tar_='find "$tardir" -print | cpio -o -H $1 -L'
100 am__untar='cpio -i -H $1 -d'
109 # If the value was cached, stop now. We just wanted to have am__tar
111 test -n "${am_cv_prog_tar_$1}" && break
113 # tar/untar a dummy directory, and stop if the command works.
116 echo GrepMe > conftest.dir/file
117 AM_RUN_LOG([tardir=conftest.dir && eval $am__tar_ >conftest.tar])
119 if test -s conftest.tar; then
120 AM_RUN_LOG([$am__untar <conftest.tar])
121 AM_RUN_LOG([cat conftest.dir/file])
122 grep GrepMe conftest.dir/file >/dev/null 2>&1 && break
127 AC_CACHE_VAL([am_cv_prog_tar_$1], [am_cv_prog_tar_$1=$_am_tool])
128 AC_MSG_RESULT([$am_cv_prog_tar_$1])])
131 AC_SUBST([am__untar])