From 901a99237203b37f862d4a34baadafb96e549e2d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jurko=20Gospodneti=C4=87?= <jurko.gospodnetic@pke.hr>
Date: Wed, 29 Aug 2012 15:52:29 +0000
Subject: [PATCH] Boost Jam cleanup on Linux/Free-BSD - replaced strndup()
 usage with malloc()/strncpy() as strndup() does not get declared in older
 glibc version header files unless some version specific symbols are defined
 first. This corrects a compiler warning on such systems about strndup()
 function being implicitly (and incorrectly) declared.

[SVN r80304]
---
 v2/engine/jam.c | 38 +++++++++++++++++++++++++++++++++++---
 1 file changed, 35 insertions(+), 3 deletions(-)

diff --git a/v2/engine/jam.c b/v2/engine/jam.c
index 551822652..271b0dacb 100644
--- a/v2/engine/jam.c
+++ b/v2/engine/jam.c
@@ -628,6 +628,8 @@ char * executable_path( char const * argv0 )
     return strdup( getexecname() );
 }
 #elif defined(__FreeBSD__)
+# include <stdlib.h>
+# include <string.h>
 # include <sys/sysctl.h>
 char * executable_path( char const * argv0 )
 {
@@ -635,15 +637,45 @@ char * executable_path( char const * argv0 )
     char buf[ 1024 ];
     size_t size = sizeof( buf );
     sysctl( mib, 4, buf, &size, NULL, 0 );
-    return ( !size || size == sizeof( buf ) ) ? NULL : strndup( buf, size );
+    if ( size && size != sizeof( buf ) )
+    {
+        /* Using strndup() here might not work with older glibc installations as
+         * their headers do not declare that function unless certain symbols are
+         * defined. We could work around this issue by defining appropriate
+         * symbols but they depend on the exact glibc version used so simply
+         * using malloc()/strncpy() seems like a cleaner solution.
+         *
+         * Note: such old glibc installations have so far only been found on
+         * Linux and not Free-BSD installations but using the same logic on
+         * Free-BSD seems like something that could not hurt.
+         */
+        char * const result = (char *)malloc( size );
+        if ( result )
+            return strncpy( result, buf, size );
+    }
+    return NULL;
 }
 #elif defined(__linux__)
+# include <stdlib.h>
+# include <string.h>
 # include <unistd.h>
 char * executable_path( char const * argv0 )
 {
     char buf[ 1024 ];
-    ssize_t const ret = readlink( "/proc/self/exe", buf, sizeof( buf ) );
-    return ( !ret || ret == sizeof( buf ) ) ? NULL : strndup( buf, ret );
+    ssize_t const size = readlink( "/proc/self/exe", buf, sizeof( buf ) );
+    if ( size && size != sizeof( buf ) )
+    {
+        /* Using strndup() here might not work with older glibc installations as
+         * their headers do not declare that function unless certain symbols are
+         * defined. We could work around this issue by defining appropriate
+         * symbols but they depend on the exact glibc version used so simply
+         * using malloc()/strncpy() seems like a cleaner solution.
+         */
+        char * const result = (char *)malloc( size );
+        if ( result )
+            return strncpy( result, buf, size );
+    }
+    return NULL;
 }
 #else
 char * executable_path( char const * argv0 )