fix: docker-entrypoint.sh file handling, closes #1456

The docker-entrypoint.sh script added in
#1039 is intended to run the
supplied command with "node" if it contains a "-" or doesn't correspond
to a system command. In Alpine, this doesn't work if the supplied
command corresponds to a regular, non-executable JS file.

The root issue is a bug in ash/dash: its implementation of "command -v"
incorrectly outputs the supplied command_name even for non-executable
files. This is a violation of the POSIX standard and has been reported
to the Debian team in
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264, though there's
been no activity in several years.

As a workaround, this adds an additional check to docker-entrypoint.sh
for regular files that aren't marked as executable.

Author: MasonM

12/alpine3.11/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi
 

12/alpine3.12/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi
 

12/alpine3.13/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi
 

12/alpine3.14/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi
 

12/bullseye-slim/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi
 

12/bullseye/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi
 

12/buster-slim/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi
 

12/buster/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi
 

12/stretch-slim/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi
 

12/stretch/docker-entrypoint.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 set -e
 
-if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
+# Run command with node if the first argument contains a "-" or is not a system command. The last
+# part inside the "{}" is a workaround for the following bug in ash/dash:
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874264
+if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ] || { [ -f "${1}" ] && ! [ -x "${1}" ]; }; then
   set -- node "$@"
 fi