fix(build): update pcre2 autoconf macro and dependencies

[fzipi]

This PR fixes pcre2 builds for extended architectures. In summary:

• moved from custom m4 to using standard macro from autoconf-archive
• updated dependent automake files
• fixed calls to echo in configure.ac to standard, to be more portable

Signed-off-by: Felipe Zipitria felipe.zipitria@owasp.org

Fixes #2810

[fzipi]

I have a less intrusive patch for this, if needed.

[martinhsv]

Only commenting on one of three aspects for now.

[fzipi]

Is this of any value, or should I close it?

[martinhsv]

@fzipi ,

I haven't looked at this since your comment #2813 (comment) .

I had understood that you were going to make some changes. But perhaps I misunderstood you?

[fzipi]

Will rebase first and split the change, you are right.

[manojkavali]

When will be Modsecurity 2.9.7 will be released ? Since we need PCRE2 support for our Apache Modsecurity Binary.

[martinhsv]

Hello @manojkavali , The v2.9.7 release has been published.

[agebhar1]

Would be great if the fix gets into v3. PCRE2 is also not found on SUSE.

[martinhsv]

Finally getting back to this.

FIrst off, I'm not clear on the precise scope of the proposed fix. In general, ModSecurity .m4 files are structured to attempt to find a dependency automatically, but to also allow the path to be specified via the configure option. Is it the case that A) one can still successfully specify the pcre2 location via the option or B) even that fallback option does not work.

A second concern is that the this PR introduces a second .m4 file for pcre2. The pattern thus far has been for a single .m4 file to deal with a particular dependency. Even if there is no problem with the two stepping on each other, I expect it's undesirable to deviate from the existing convention unless it's truly necessary.

Finally, the introduction of the include 'config.h' requires more information. What is this file exactly? Are the required pcre2 definitions housed in this file in some of those more esoteric environments? I'm a little uneasy about making presumptions about what a "config.h" file is and including it this way. For one thing, what if at some point a "config.h" file is created within ModSecurity's /src directory at some point in the future. What is some other component or dependency has a "config.h" file.

[agebhar1]

I'm not able to reproduce it anymore. Add the --with-pcre2 works on SuSE to detect PCRE2. From the config.log:

…
configure:6934: PCRE2 support was marked as mandatory by the utilization of --with-pcre2=yes
configure:6956: Nothing about PCRE2 was informed during the configure phase. Trying to detect it on the platform...
configure:7022: PCRE2 headers found at: /usr/include
configure:7017: PCRE2 library found at: /usr/lib64//libpcre2-8.so
configure:7022: PCRE2 headers found at: /usr/include
configure:7017: PCRE2 library found at: /usr/lib64//libpcre2-8.so
configure:7022: PCRE2 headers found at: /usr/include
configure:7092: PCRE2 library found at: /usr/lib64//libpcre2-8.so
configure:7097: PCRE2 headers found at: /usr/include
configure:7133: using PCRE2 v
…
PCRE2_CFLAGS='-DWITH_PCRE2 -I/usr/include'
PCRE2_CFLAGS_FALSE='#'
PCRE2_CFLAGS_TRUE=''
PCRE2_DISPLAY='-lpcre2-8, -DWITH_PCRE2 -I/usr/include'
PCRE2_FOUND='1'
PCRE2_LDADD='-lpcre2-8'
PCRE2_LDFLAGS='-L/usr/lib64/'
PCRE2_LIBS=''
PCRE2_VERSION=''
…

But, the information is not taken from pkg-config, since at SuSE the library is not within PCRE2_POSSIBLE_LIB_NAMES.

$ pkg-config --list-all | grep pcre
libpcreposix     libpcreposix - PCREPosix - Posix compatible interface to libpcre
libpcrecpp       libpcrecpp - PCRECPP - C++ wrapper for PCRE
libpcre2-8       libpcre2-8 - PCRE2 - Perl compatible regular expressions C library (2nd API) with 8 bit character support
libpcre          libpcre - PCRE - Perl compatible regular expressions C library with 8 bit character support
libpcre2-posix   libpcre2-posix - Posix compatible interface to libpcre2-8
libpcre2-16      libpcre2-16 - PCRE2 - Perl compatible regular expressions C library (2nd API) with 16 bit character support
libpcre2-32      libpcre2-32 - PCRE2 - Perl compatible regular expressions C library (2nd API) with 32 bit character support
libpcre16        libpcre16 - PCRE - Perl compatible regular expressions C library with 16 bit character support

The commit from @fzipi fix(build): add libpcre2-8 to possible names resolves the issue and pkg-config can request the information about PCRE2.

[martinhsv]

Thanks @agebhar1 for the clarification.

Even though there was no problem with the overall functionality, for the sake of completeness/tidiness, I have gone ahead and merged that narrower change via #2939 .

I'll go ahead and close this item.