From 58553216380b1c343e501be5dd2f707b45b3aff5 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Fri, 24 May 2019 15:24:18 +0100
Subject: [PATCH] improve realpath() compat on older libc

older libc didn't allow a NULL for the second param
---
 ChangeLog              |  3 +++
 configure.ac           |  6 +++---
 libvips/iofuncs/init.c | 13 +++++--------
 libvips/iofuncs/util.c | 11 ++++++-----
 4 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 52e1e299..b0fce75e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+24/5/19 started 8.8.1
+- improve realpath() use on older libc
+
 21/9/18 started 8.8.0
 - much faster smartcrop [lovell]
 - add low/high to smartcrop [jcupitt]
diff --git a/configure.ac b/configure.ac
index 6844c671..826b3b34 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@
 
 # also update the version number in the m4 macros below
 
-AC_INIT([vips], [8.8.0], [vipsip@jiscmail.ac.uk])
+AC_INIT([vips], [8.8.1], [vipsip@jiscmail.ac.uk])
 # required for gobject-introspection
 AC_PREREQ(2.62)
 
@@ -18,7 +18,7 @@ AC_CONFIG_MACRO_DIR([m4])
 # user-visible library versioning
 m4_define([vips_major_version], [8])
 m4_define([vips_minor_version], [8])
-m4_define([vips_micro_version], [0])
+m4_define([vips_micro_version], [1])
 m4_define([vips_version],
           [vips_major_version.vips_minor_version.vips_micro_version])
 
@@ -38,7 +38,7 @@ VIPS_VERSION_STRING=$VIPS_VERSION-`date -u -r ChangeLog`
 #   binary interface changes not backwards compatible?: reset age to 0
 
 LIBRARY_CURRENT=52
-LIBRARY_REVISION=0
+LIBRARY_REVISION=1
 LIBRARY_AGE=10
 
 # patched into include/vips/version.h
diff --git a/libvips/iofuncs/init.c b/libvips/iofuncs/init.c
index eb8bbda9..87008822 100644
--- a/libvips/iofuncs/init.c
+++ b/libvips/iofuncs/init.c
@@ -979,24 +979,22 @@ guess_prefix( const char *argv0, const char *name )
 		}
         }
 
-#ifdef HAVE_REALPATH
-	/* Try to guess from cwd. Only if this is a relative path, though. No
- 	 * realpath on winders, but fortunately it seems to always generate
- 	 * a full path in argv[0].
+	/* Try to guess from cwd. Only if this is a relative path, though. 
 	 */
 	if( !g_path_is_absolute( argv0 ) ) {
+		char *dir;
 		char full_path[VIPS_PATH_MAX];
 		char *resolved;
-		char *dir;
 
 		dir = g_get_current_dir(); 
 		vips_snprintf( full_path, VIPS_PATH_MAX, 
 			"%s" G_DIR_SEPARATOR_S "%s", dir, argv0 );
 		g_free( dir ); 
 
-		if( (resolved = realpath( full_path, NULL )) ) {
+		if( (resolved = vips_realpath( full_path )) ) {
 			prefix = extract_prefix( resolved, name );
-			free( resolved ); 
+			g_free( resolved );
+
 			if( prefix ) { 
 #ifdef DEBUG
 				printf( "vips_guess_prefix: found \"%s\" "
@@ -1006,7 +1004,6 @@ guess_prefix( const char *argv0, const char *name )
 			}
 		}
 	}
-#endif /*HAVE_REALPATH*/
 
 	/* Fall back to the configure-time prefix.
 	 */
diff --git a/libvips/iofuncs/util.c b/libvips/iofuncs/util.c
index e0eeb734..efb4643e 100644
--- a/libvips/iofuncs/util.c
+++ b/libvips/iofuncs/util.c
@@ -1875,9 +1875,12 @@ vips_realpath( const char *path )
 
 #ifdef HAVE_REALPATH
 {
-	char *real2;
+	char buf[PATH_MAX];
 
-	if( !(real = realpath( path, NULL )) ) {
+	/* More modern realpath() allow NULL for the second param, but we want
+	 * to work with older libc as well.
+	 */
+	if( !(real = realpath( path, buf )) ) {
 		vips_error_system( errno, "vips_realpath",
 			"%s", _( "unable to form filename" ) ); 
 		return( NULL );
@@ -1885,9 +1888,7 @@ vips_realpath( const char *path )
 
 	/* We must return a path that can be freed with g_free().
 	 */
-	real2 = g_strdup( real );
-	free( real );
-	real = real2;
+	real = g_strdup( real );
 }
 #else /*!HAVE_REALPATH*/
 {