grep: improve PCRE2 version output

* src/grep.c: No need to include pcre2.h.
(main) [HAVE_LIBPCRE]: Call Pprint_version instead of
doing it ourselves.
* src/pcresearch.c (Pprint_version): New function.
It also checks belatedly for buffer overflow, and
says "grep -P uses PCRE2" instead of "Built with PCRE".
* tests/version-pcre: Adjust test to match.

5 files changed, 14 insertions, 12 deletions

diff --git a/NEWS b/NEWS
index 029aaf1c..3fdf4fe3 100644
--- a/NEWS
+++ b/NEWS
@@ -18,9 +18,9 @@ GNU grep NEWS                                    -*- outline -*-
 
   grep --version now prints a line describing the version of PCRE2 it uses.
   For example, it prints this when built with the very latest from git:
-    Built with PCRE 10.43-DEV 2023-01-15
+    grep -P uses PCRE2 10.43-DEV 2023-01-15
   or this with what's currently available in Fedora 37:
-    Built with PCRE 10.40 2022-04-14
+    grep -P uses PCRE2 10.40 2022-04-14
 
 
 * Noteworthy changes in release 3.10 (2023-03-22) [stable]
diff --git a/src/grep.c b/src/grep.c
index bd776e8b..491dd028 100644
--- a/src/grep.c
+++ b/src/grep.c
@@ -29,11 +29,6 @@
 #include <stdio.h>
 #include "system.h"
 
-#if HAVE_LIBPCRE
-# define PCRE2_CODE_UNIT_WIDTH 8
-# include <pcre2.h>
-#endif
-
 #include "argmatch.h"
 #include "c-ctype.h"
 #include "c-stack.h"
@@ -2836,10 +2831,7 @@ main (int argc, char **argv)
       puts (_("Written by Mike Haertel and others; see\n"
               "<https://git.savannah.gnu.org/cgit/grep.git/tree/AUTHORS>."));
 #if HAVE_LIBPCRE
-      unsigned char buf[128];
-      (void) pcre2_config (PCRE2_CONFIG_VERSION, buf);
-      fputs (_("\nBuilt with PCRE "), stdout);
-      puts ((char *) buf);
+      Pprint_version ();
 #endif
       return EXIT_SUCCESS;
     }
diff --git a/src/pcresearch.c b/src/pcresearch.c
index e77509c4..9e2f393d 100644
--- a/src/pcresearch.c
+++ b/src/pcresearch.c
@@ -74,6 +74,15 @@ private_free (void *ptr, _GL_UNUSED void *unused)
   free (ptr);
 }
 
+void
+Pprint_version (void)
+{
+  char buf[128];
+  if (sizeof buf <= pcre2_config (PCRE2_CONFIG_VERSION, buf))
+    abort ();
+  printf (_("\ngrep -P uses PCRE2 %s\n"), buf);
+}
+
 /* Match the already-compiled PCRE pattern against the data in SUBJECT,
    of size SEARCH_BYTES and starting with offset SEARCH_OFFSET, with
    options OPTIONS.
diff --git a/src/search.h b/src/search.h
index 61d65626..ebb9d070 100644
--- a/src/search.h
+++ b/src/search.h
@@ -65,6 +65,7 @@ extern ptrdiff_t Fexecute (void *, char const *, idx_t, idx_t *, char const *);
 /* pcresearch.c */
 extern void *Pcompile (char *, idx_t, reg_syntax_t, bool);
 extern ptrdiff_t Pexecute (void *, char const *, idx_t, idx_t *, char const *);
+extern void Pprint_version (void);
 
 /* grep.c */
 extern struct localeinfo localeinfo;
diff --git a/tests/version-pcre b/tests/version-pcre
index d18daa69..c7bb182f 100755
--- a/tests/version-pcre
+++ b/tests/version-pcre
@@ -12,4 +12,4 @@
 grep -q '^#define HAVE_LIBPCRE 1' "$CONFIG_HEADER" \
   || skip_ 'built without PCRE support'
 
-grep --version | grep -qP '^Built with PCRE [\d.]+'
+grep --version | grep -qP '^grep -P uses PCRE2 [\d.]+'