diff options
| -rwxr-xr-x | nextbin | 116 | ||||
| -rwxr-xr-x | test/a/x | 3 | ||||
| -rwxr-xr-x | test/b/x | 3 | ||||
| -rwxr-xr-x | test/c/x | 3 | ||||
| -rwxr-xr-x | test/start | 59 |
5 files changed, 162 insertions, 22 deletions
@@ -1,31 +1,103 @@ #!/bin/sh -orig_exe=$(realpath -s "$1") +set -e + +die() { + fmt=$1 + shift + printf "nextbin %s failed: $fmt\n" "$orig_exe" "$@" >&2 + exit 1 +} + +usage() { + # shellcheck disable=SC2016 + echo 'usage: nextbin [-v] "$0" "$@"' >&2 +} + +case "$1" in + -v) action="echo"; shift;; + -*|'') usage; exit 1;; + *) action="exec" +esac +orig_exe=$1 +shift exe_name=${orig_exe##*/} + +[ -n "$PATH" ] || die 'PATH is empty' + case "$orig_exe" in - */*) ;; + */) + die 'ends with /' + ;; + + */*) + orig_dir=${orig_exe%/*} + ;; + *) - printf 'error: cannot find next executable: argv[0] is %s, missing /\n' "$orig_exe" - exit 1 + # either shell has not resolved script-file into a path, or script is + # in cwd and PATH has . or empty entries + if ! [ -d "$orig_exe" ] && [ -x "$orig_exe" ]; then + case ":$PATH:" in + *::*:.:*|*:.:*::*) + die 'exe in cwd and PATH has both . and empty entries' + ;; + + *::*) + orig_dir= + ;; + + *:.:*) + orig_dir=. + ;; + + *) + die 'missing /' + esac + fi esac -paths= -passed_paths= -set -f -_IFS=$IFS -IFS=: -for path in $PATH; do - file=$path/$exe_name - if [ "$file" = "$orig_exe" ]; then - if [ -n "$passed_paths" ] && [ -n "$paths" ]; then - printf 'error: ambiguous next executable for %s past %s, due to multiple non-consecutive instances of %s in PATH' "$exe_name" "$orig_exe" "$(dirname "$orig_exe")" - exit 1 + +tmp_path=:$PATH: +new_path=${tmp_path#*:$orig_dir:} +[ -n "$new_path" ] \ + || die '%s is last PATH entry' "$orig_dir" +if [ "$new_path" != "$tmp_path" ]; then + new_path_2=${new_path#*:$orig_dir:} + [ "$new_path" = "$new_path_2" ] \ + || die 'duplicate entry in PATH: %s' \ + "$orig_exe" "$orig_dir" +else + # try to find equivalent path + found_alt_dir= + new_orig_dir= + equiv_orig_dir=$(cd "${orig_dir:-.}" && pwd -L) + tmp_path_2=$PATH + while :; do + p=${tmp_path_2%%:*} + if [ "$(cd "$p" >/dev/null 2>&1 && pwd -L)" = "$equiv_orig_dir" ]; then + [ -z "$found_alt_dir" ] \ + || die "duplicate equivalent path in PATH: '%s' = '%s'" \ + "$new_orig_dir" "$p" + found_alt_dir=1 + new_orig_dir=$p fi - passed_paths=${paths+$paths:} - paths= + case "$tmp_path_2" in + *:*) tmp_path_2=${tmp_path_2#*:};; + *) break + esac + done + if [ -n "$found_alt_dir" ]; then + new_path=${tmp_path#*:$new_orig_dir:} + [ -n "$new_path" ] \ + || die '%s is last PATH entry' "$new_orig_dir" else - paths="${paths+$paths:}$path" + new_path=$PATH: fi -done -IFS=$_IFS -PATH="$passed_paths$paths" exec "$exe_name" -exit 1 +fi + +exe=$(PATH="${new_path%:}" command -v "$exe_name") || true +[ -n "$exe" ] \ + || die 'PATH lookup failed using %s' \ + "${new_path%:}" + +$action "$exe" "$@" diff --git a/test/a/x b/test/a/x new file mode 100755 index 0000000..e7d6387 --- /dev/null +++ b/test/a/x @@ -0,0 +1,3 @@ +#!/bin/sh +echo "in a with $0, next" +nextbin "$0" "$@" diff --git a/test/b/x b/test/b/x new file mode 100755 index 0000000..0355509 --- /dev/null +++ b/test/b/x @@ -0,0 +1,3 @@ +#!/bin/sh +echo "in b with $0, next" +nextbin "$0" "$@" diff --git a/test/c/x b/test/c/x new file mode 100755 index 0000000..cc0070b --- /dev/null +++ b/test/c/x @@ -0,0 +1,3 @@ +#!/bin/sh +echo "in c with $0, done" +exit 0 diff --git a/test/start b/test/start new file mode 100755 index 0000000..4cf0d9d --- /dev/null +++ b/test/start @@ -0,0 +1,59 @@ +#!/bin/sh + +set -e + +cd "${0%/*}" +exec 2>&1 + +check() { + for arg in $1; do + read -r line || { echo "FAIL: insufficient output" >&2; return 1; } + echo "GOT: $line" + case "$arg" in + [a-z]) case "$line" in "in $arg "*) ;; *) echo "FAIL: expected $arg" >&2; return 1; esac;; + err) case "$line" in nextbin*failed*) ;; *) echo "FAIL: expected err" >&2; return 1; esac;; + *) echo "INVALID TEST" >&2; exit 1 + esac + done + if read -r line; then + echo "FAIL: too much output" >&2 + return 1 + fi + echo "OK" +} + +try() { + # shellcheck disable=SC2016 + printf 'TEST: PATH="$PATH:%s" %s, expect %s\n' "$@" + PATH="$PATH:$1" "$2" 2>&1 | check "$3" + # shellcheck disable=SC2016 + printf 'TEST: PATH="%s:$PATH" %s, expect %s\n' "$@" + PATH="$1:$PATH" "$2" 2>&1 | check "$3" +} + +do_try() { + try "$1" "$2/x" "$3" + try "$1" "./$2/x" "$3" + try "$1" "$PWD/$2/x" "$3" + try "$1" "$2/../$2/x" "$3" + try "$1" "./$2/../$2/x" "$3" + try "$1" "$PWD/$2/../$2/x" "$3" + echo +} + +do_try2() { + try "$1" "x" "$3" + do_try "$@" +} + +export PATH="$PWD/..:$PATH" + +do_try "" a "a err" +do_try2 "$PWD/a" a "a err" +do_try "$PWD/b" a "a b err" +do_try2 "$PWD/a:$PWD/b" a "a b err" +do_try "$PWD/a:$PWD/b" b "b err" +do_try2 "$PWD/a:$PWD/b:$PWD/c" a "a b c" +do_try "$PWD/a:$PWD/b:$PWD/c" b "b c" + +echo "ALL TESTS COMPLETED SUCCESSFULLY :)" |