diff options
Diffstat (limited to 'bin')
| -rwxr-xr-x | bin/sbang | 154 |
1 files changed, 106 insertions, 48 deletions
@@ -1,4 +1,4 @@ -#!/bin/bash +#!/bin/sh # # Copyright 2013-2020 Lawrence Livermore National Security, LLC and other # Spack Project Developers. See the top-level COPYRIGHT file for details. @@ -8,32 +8,34 @@ # # `sbang`: Run scripts with long shebang lines. # -# Many operating systems limit the length of shebang lines, making it -# hard to use interpreters that are deep in the directory hierarchy. +# Many operating systems limit the length and number of possible +# arguments in shebang lines, making it hard to use interpreters that are +# deep in the directory hierarchy or require special arguments. +# # `sbang` can run such scripts, either as a shebang interpreter, or # directly on the command line. # # Usage -# ----------------------------- +# ----- # Suppose you have a script, long-shebang.sh, like this: # -# 1 #!/very/long/path/to/some/interpreter +# 1 #!/very/long/path/to/some/interp # 2 # 3 echo "success!" # # Invoking this script will result in an error on some OS's. On # Linux, you get this: # -# $ ./long-shebang.sh -# -bash: ./long: /very/long/path/to/some/interp: bad interpreter: +# $ ./longshebang.sh +# -bash: ./longshebang.sh: /very/long/path/to/some/interp: bad interpreter: # No such file or directory # -# On Mac OS X, the system simply assumes the interpreter is the shell -# and tries to run with it, which is likely not what you want. +# On macOS, the system simply assumes the interpreter is the shell and +# tries to run with it, which is not likely what you want. # # # `sbang` on the command line -# ----------------------------- +# --------------------------- # You can use `sbang` in two ways. The first is to use it directly, # from the command line, like this: # @@ -42,12 +44,12 @@ # # # `sbang` as the interpreter -# ----------------------------- +# -------------------------- # You can also use `sbang` *as* the interpreter for your script. Put -# `#!/bin/bash /path/to/sbang` on line 1, and move the original +# `#!/bin/sh /path/to/sbang` on line 1, and move the original # shebang to line 2 of the script: # -# 1 #!/bin/bash /path/to/sbang +# 1 #!/bin/sh /path/to/sbang # 2 #!/long/path/to/real/interpreter with arguments # 3 # 4 echo "success!" @@ -56,10 +58,10 @@ # success! # # On Linux, you could shorten line 1 to `#!/path/to/sbang`, but other -# operating systems like Mac OS X require the interpreter to be a -# binary, so it's best to use `sbang` as a `bash` argument. -# Obviously, for this to work, `sbang` needs to have a short enough -# path that *it* will run without hitting OS limits. +# operating systems like Mac OS X require the interpreter to be a binary, +# so it's best to use `sbang` as an argument to `/bin/sh`. Obviously, for +# this to work, `sbang` needs to have a short enough path that *it* will +# run without hitting OS limits. # # For Lua, node, and php scripts, the second line can't start with #!, as # # is not the comment character in these languages (though they all @@ -67,59 +69,115 @@ # like this, using --, //, or <?php ... ?> instead of # on the second # line, e.g.: # -# 1 #!/bin/bash /path/to/sbang +# 1 #!/bin/sh /path/to/sbang # 2 --!/long/path/to/lua with arguments # 3 print "success!" # -# 1 #!/bin/bash /path/to/sbang +# 1 #!/bin/sh /path/to/sbang # 2 //!/long/path/to/node with arguments # 3 print "success!" # -# 1 #!/bin/bash /path/to/sbang +# 1 #!/bin/sh /path/to/sbang # 2 <?php #/long/path/to/php with arguments ?> # 3 <?php echo "success!\n"; ?> # # How it works -# ----------------------------- -# `sbang` is a very simple bash script. It looks at the first two -# lines of a script argument and runs the last line starting with -# `#!`, with the script as an argument. It also forwards arguments. +# ------------ +# `sbang` is a very simple posix shell script. It looks at the first two +# lines of a script argument and runs the last line starting with `#!`, +# with the script as an argument. It also forwards arguments. # +# We disable two shellcheck errors below: +# SC2124: when saving arguments, we intentionally assign as an array +# SC2086: when splitting $shebang_line and exec args, we want to expand args + +# Generic error handling +die() { + echo "$@" 1>&2; + exit 1 +} + +# set SBANG_DEBUG to make the script print what would normally be executed. +exec="exec" +if [ -n "${SBANG_DEBUG}" ]; then + exec="echo " +fi + # First argument is the script we want to actually run. script="$1" +# ensure that the script actually exists +if [ -z "$script" ]; then + die "error: sbang requires exactly one argument" +elif [ ! -f "$script" ]; then + die "$script: no such file or directory" +fi + # Search the first two lines of script for interpreters. lines=0 -while read line && ((lines < 2)) ; do - if [[ "$line" = '#!'* ]]; then - interpreter="${line#\#!}" - elif [[ "$line" = '//!'*node* ]]; then - interpreter="${line#//!}" - elif [[ "$line" = '--!'*lua* ]]; then - interpreter="${line#--!}" - elif [[ "$line" = '<?php #!'*php* ]]; then - interpreter="${line#<?php\ \#!}" - interpreter="${interpreter%\ ?>}" +while read -r line && [ $lines -ne 2 ]; do + if [ "${line#\#!}" != "$line" ]; then + shebang_line="${line#\#!}" + elif [ "${line#//!}" != "$line" ]; then # // comments + shebang_line="${line#//!}" + elif [ "${line#--!}" != "$line" ]; then # -- lua comments + shebang_line="${line#--!}" + elif [ "${line#<?php\ }" != "$line" ]; then # php comments + shebang_line="${line#<?php\ \#!}" + shebang_line="${shebang_line%\ ?>}" fi lines=$((lines+1)) done < "$script" -# this is ineeded for scripts with sbang parameter -# like ones in intltool -# #!/<spack-long-path>/perl -w -# this is the interpreter line with all the parameters as a vector -interpreter_v=(${interpreter}) -# this is the single interpreter path -interpreter_f="${interpreter_v[0]}" -# Invoke any interpreter found, or raise an error if none was found. -if [[ -n "$interpreter_f" ]]; then - if [[ "${interpreter_f##*/}" = "perl"* ]]; then - exec $interpreter -x "$@" +# shellcheck disable=SC2124 +# this saves arguments for later and intentionally assigns as an array +args="$@" + +# handle scripts with sbang parameters, e.g.: +# +# #!/<spack-long-path>/perl -w +# +# put the shebang line with all the parameters in the $@ array and get +# the first element. +# shellcheck disable=SC2086 +set $shebang_line +set -- "$@" +interpreter="$1" +arg1="$2" + +# error if we did not find any interpreter +if [ -z "$interpreter" ]; then + die "error: sbang found no interpreter in $script" +fi + +# Determine if the interpreter is a particular program, accounting for the +# '#!/usr/bin/env PROGRAM' convention. So: +# +# interpreter_is perl +# +# will be true for '#!/usr/bin/perl' and '#!/usr/bin/env perl' +interpreter_is() { + if [ "${interpreter##*/}" = "$1" ]; then + return 0 + elif [ "$interpreter" = "/usr/bin/env" ] && [ "$arg1" = "$1" ]; then + return 0 else - exec $interpreter "$@" + return 1 fi +} + +if interpreter_is "sbang"; then + die "error: refusing to re-execute sbang to avoid infinite loop." +fi + +# Finally invoke the real shebang line +# ruby and perl need -x to ignore the first line of input (the sbang line) +# +if interpreter_is perl || interpreter_is ruby; then + # shellcheck disable=SC2086 + $exec $shebang_line -x "$args" else - echo "error: sbang found no interpreter in $script" - exit 1 + # shellcheck disable=SC2086 + $exec $shebang_line "$args" fi |