build/*.m4: Remove Bashisms/POSIX-ify the M4 helper macros #3359
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This commit makes it possible to build ModSecurity on systems where
/bin/sh is a POSIX-compliant shell that is not Bash. Debian, Alpine
Linux, and Gentoo Linux with the system shell set to not Bash, are
examples of such systems.
Previously, the helper macros contained two types of Bashisms:
* The '==' comparison operator. Very easy to change, as the proper
POSIX-compliant form is '='. For example:
if test "${var}" == "myvalue" -> if test "${var}" = "myvalue"
* The '-a' (and) operator in the 'test' builtin. The '-a' and '-o'
operators were removed in POSIX 2024 (Issue 8). The correct form
is to use the '&&' and '||' operators respectively. For instance:
if test -d "${var}" -a -r "${var}/file" ->
if test -d "${var}" && test -r "${var}/file"
Bug: https://bugs.gentoo.org/887135
Signed-off-by: Zurab Kvachadze <[email protected]>
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| @@ -21,7 +21,7 @@ AC_ARG_WITH( | |||
| [test_paths="${with_pcre}"], | |||
| [test_paths="/usr/local/libpcre /usr/local/pcre /usr/local /opt/libpcre /opt/pcre /opt /usr /opt/local"]) | |||
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| if test "x${with_pcre}" == "x" && test "x${with_pcre}" != "xno"; then | |||
| if test "x${with_pcre}" = "x" && test "x${with_pcre}" != "xno"; then | |||
There was a problem hiding this comment.
Please take a look at this comment from @theseion. I think he is right, and (unfortunately) we should review all complex conditions.
Moreover, I don't know: do we want to handle the yes value in case of all --with... options?
Here are the output of different scenarios (tested with these expressions):
if test "x${with_pcre}" = "x" && test "x${with_pcre}" != "xno"; then echo "TRUE"; else echo "FALSE";
if test "x${with_pcre}" = "x" || test "x${with_pcre}" != "xno"; then echo "TRUE"; else echo "FALSE";
Value of with_pcre |
expected output | real output | meanings |
|---|---|---|---|
condition: && |
|||
"" (empty) |
TRUE | TRUE | --with-pcre - we want to use PCRE |
yes |
TRUE | FALSE! | --with-pcre=yes - we want to use PCRE |
no |
FALSE | FALSE | --with-pcre=no - we do not want to use PCRE |
condition: || |
|||
"" (empty) |
TRUE | TRUE | --with-pcre - we want to use PCRE |
yes |
TRUE | TRUE | --with-pcre=yes - we want to use PCRE |
no |
FALSE | FALSE | --with-pcre=no - we do not want to use PCRE |
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Hi @BalkanMadman, first of all, many thanks for this PR. I think this is a really important patch, we must apply this. Please take a look at my comment above - I don't expect you to review all conditions, but that would be a huge help for the project. Also, could you take a look at the v2/master tree too, and make this modifications? |
This commit makes it possible to build ModSecurity on systems where /bin/sh is a POSIX-compliant shell that is not Bash. Debian, Alpine Linux, and Gentoo Linux with the system shell set to not Bash, are examples of such systems.
Previously, the helper macros contained two types of Bashisms:
==comparison operator. Very easy to change, as the proper POSIX-compliant form is=. For example:Bug: https://bugs.gentoo.org/887135
what
==operator changed to the POSIX-compliant=.-aoperator changed to the compliant&&.why
/bin/shis not Bash (is dash, ash, etc.). See the Gentoo bug below.references