From 3a9b0bd6344816e166170bceef0064a22684d9ab Mon Sep 17 00:00:00 2001 From: Benjamin Esham Date: Sat, 17 Aug 2019 19:12:14 -0700 Subject: [PATCH] add shortenPerlShebang function This setup hook modifies a Perl script so that any "-I" flags in its shebang line are rewritten into a "use lib ..." statement on the next line. This gets around a limitation in Darwin, which will not properly handle a script whose shebang line exceeds 511 characters. --- doc/languages-frameworks/perl.xml | 33 ++++++- .../setup-hooks/shorten-perl-shebang.sh | 88 +++++++++++++++++++ pkgs/top-level/all-packages.nix | 4 + 3 files changed, 124 insertions(+), 1 deletion(-) create mode 100644 pkgs/build-support/setup-hooks/shorten-perl-shebang.sh diff --git a/doc/languages-frameworks/perl.xml b/doc/languages-frameworks/perl.xml index d0f124f29d4..065212a0e18 100644 --- a/doc/languages-frameworks/perl.xml +++ b/doc/languages-frameworks/perl.xml @@ -75,7 +75,8 @@ foo = import ../path/to/foo.nix { It adds the contents of the PERL5LIB environment variable to #! .../bin/perl line of Perl scripts as -Idir flags. This ensures - that a script can find its dependencies. + that a script can find its dependencies. (This can cause this shebang line + to become too long for Darwin to handle; see the note below.) @@ -137,6 +138,36 @@ ClassC3Componentised = buildPerlPackage rec { + + On Darwin, if a script has too many + -Idir flags in its first line + (its “shebang line”), it will not run. This can be worked around by calling + the shortenPerlShebang function from the + postInstall phase: + +{ stdenv, buildPerlPackage, fetchurl, shortenPerlShebang }: + +ImageExifTool = buildPerlPackage { + pname = "Image-ExifTool"; + version = "11.50"; + + src = fetchurl { + url = "https://www.sno.phy.queensu.ca/~phil/exiftool/Image-ExifTool-11.50.tar.gz"; + sha256 = "0d8v48y94z8maxkmw1rv7v9m0jg2dc8xbp581njb6yhr7abwqdv3"; + }; + + buildInputs = stdenv.lib.optional stdenv.isDarwin shortenPerlShebang; + postInstall = stdenv.lib.optional stdenv.isDarwin '' + shortenPerlShebang $out/bin/exiftool + ''; +}; + + This will remove the -I flags from the shebang line, + rewrite them in the use lib form, and put them on the next + line instead. This function can be given any number of Perl scripts as + arguments; it will modify them in-place. + +
Generation from CPAN diff --git a/pkgs/build-support/setup-hooks/shorten-perl-shebang.sh b/pkgs/build-support/setup-hooks/shorten-perl-shebang.sh new file mode 100644 index 00000000000..4bf7c0ff1af --- /dev/null +++ b/pkgs/build-support/setup-hooks/shorten-perl-shebang.sh @@ -0,0 +1,88 @@ +# This setup hook modifies a Perl script so that any "-I" flags in its shebang +# line are rewritten into a "use lib ..." statement on the next line. This gets +# around a limitation in Darwin, which will not properly handle a script whose +# shebang line exceeds 511 characters. +# +# Each occurrence of "-I /path/to/lib1" or "-I/path/to/lib2" is removed from +# the shebang line, along with the single space that preceded it. These library +# paths are placed into a new line of the form +# +# use lib "/path/to/lib1", "/path/to/lib2"; +# +# immediately following the shebang line. If a library appeared in the original +# list more than once, only its first occurrence will appear in the output +# list. In other words, the libraries are deduplicated, but the ordering of the +# first appearance of each one is preserved. +# +# Any flags other than "-I" in the shebang line are left as-is, and the +# interpreter is also left alone (although the script will abort if the +# interpreter does not seem to be either "perl" or else "env" with "perl" as +# its argument). Each line after the shebang line is left unchanged. Each file +# is modified in place. +# +# Usage: +# shortenPerlShebang SCRIPT... + +shortenPerlShebang() { + while [ $# -gt 0 ]; do + _shortenPerlShebang "$1" + shift + done +} + +_shortenPerlShebang() { + local program="$1" + + echo "shortenPerlShebang: rewriting shebang line in $program" + + if ! isScript "$program"; then + die "shortenPerlShebang: refusing to modify $program because it is not a script" + fi + + local temp="$(mktemp)" + + gawk ' + (NR == 1) { + if (!($0 ~ /\/(perl|env +perl)\>/)) { + print "shortenPerlShebang: script does not seem to be a Perl script" > "/dev/stderr" + exit 1 + } + idx = 0 + while (match($0, / -I ?([^ ]+)/, pieces)) { + matches[idx] = pieces[1] + idx++ + $0 = gensub(/ -I ?[^ ]+/, "", 1, $0) + } + print $0 + if (idx > 0) { + prefix = "use lib " + for (idx in matches) { + path = matches[idx] + if (!(path in seen)) { + printf "%s\"%s\"", prefix, path + seen[path] = 1 + prefix = ", " + } + } + print ";" + } + } + (NR > 1 ) { + print + } + ' "$program" > "$temp" || die + # Preserve the mode of the original file + cp --preserve=mode --attributes-only "$program" "$temp" + mv "$temp" "$program" + + # Measure the new shebang line length and make sure it's okay. We subtract + # one to account for the trailing newline that "head" included in its + # output. + local new_length=$(( $(head -n 1 "$program" | wc -c) - 1 )) + + # Darwin is okay when the shebang line contains 511 characters, but not + # when it contains 512 characters. + if [ $new_length -ge 512 ]; then + die "shortenPerlShebang: shebang line is $new_length characters--still too long for Darwin!" + fi +} diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix index 3bb3c5a358a..f5d87f28f73 100644 --- a/pkgs/top-level/all-packages.nix +++ b/pkgs/top-level/all-packages.nix @@ -384,6 +384,10 @@ in setupSystemdUnits = callPackage ../build-support/setup-systemd-units.nix { }; + shortenPerlShebang = makeSetupHook + { deps = [ dieHook ]; } + ../build-support/setup-hooks/shorten-perl-shebang.sh; + singularity-tools = callPackage ../build-support/singularity-tools { }; srcOnly = args: callPackage ../build-support/src-only args;