[PATCH] Allow to specify private ld-linux

[probono]

This patch allows to tell Wine to use a privately bundled
ld-linux.so.2 (and related glibc and other libraries) instead of
looking for them in the host system.

This greatly simplifies packaging Wine as a self-standing bundle for
Linux (e.g., AppDir, AppImage), making it possible to run Wine without
installation, even on 64-bit systems on which 32-bit compatibility
libraries are not installed.

The problem statement has been described in more detail by me in
https://www.winehq.org/pipermail/wine-devel/2017-November/119906.html

The approach was suggested by Alexandre Julliard in
https://www.winehq.org/pipermail/wine-devel/2017-November/119944.html

All credit for this patch goes to Hackerl, on whose behalf I am posting.

Source: https://github.com/Hackerl/wine/commit/4f7f784.patch
Discussion: https://github.com/Hackerl/Wine_Appimage/issues/11

From: Hackerl <490021209 at qq.com>

Signed-off-by: Hackerl <490021209 at qq.com>
---
 libs/wine/config.c | 21 ++++++++++++++++++++-
 loader/preloader.c | 10 +++++++---
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/libs/wine/config.c b/libs/wine/config.c
index 083e263ee3d..e89c2c63a95 100644
--- a/libs/wine/config.c
+++ b/libs/wine/config.c
@@ -562,7 +562,26 @@ static void preloader_exec( char **argv, int
use_preloader )
         free( new_argv );
         free( full_name );
     }
-    execv( argv[0], argv );
+    else
+    {
+        char * wineloader = getenv("WINELDLIBRARY");
+
+        if (wineloader == NULL)
+            execv( argv[0], argv );
+
+        char **last_arg = argv;
+
+        while (*last_arg) last_arg++;
+
+        char ** new_argv = xmalloc( (last_arg - argv + 2) * sizeof(*argv) );
+        memcpy( new_argv + 1, argv, (last_arg - argv + 1) * sizeof(*argv) );
+
+        new_argv[0] = wineloader;
+
+        execv(wineloader, new_argv);
+
+        free( new_argv );
+    }
 }

 /* exec a wine internal binary (either the wine loader or the wine server) */
diff --git a/loader/preloader.c b/loader/preloader.c
index 13a6ad86b20..55af8383773 100644
--- a/loader/preloader.c
+++ b/loader/preloader.c
@@ -1255,7 +1255,7 @@ void* wld_start( void **stack )
 {
     long i, *pargc;
     char **argv, **p;
-    char *interp, *reserve = NULL;
+    char *interp = NULL, *reserve = NULL;
     struct wld_auxv new_av[8], delete_av[3], *av;
     struct wld_link_map main_binary_map, ld_so_map;
     struct wine_preload_info **wine_main_preload_info;
@@ -1270,8 +1270,11 @@ void* wld_start( void **stack )
     /* skip over the environment */
     while (*p)
     {
-        static const char res[] = "WINEPRELOADRESERVE=";
+        static const char res[] = "WINEPRELOADRESERVE=", loader[] =
"WINELDLIBRARY=";
+
         if (!wld_strncmp( *p, res, sizeof(res)-1 )) reserve = *p +
sizeof(res) - 1;
+        if (!wld_strncmp( *p, loader, sizeof(loader)-1 )) interp = *p
+ sizeof(loader) - 1;
+
         p++;
     }

@@ -1323,7 +1326,8 @@ void* wld_start( void **stack )
     map_so_lib( argv[1], &main_binary_map );

     /* load the ELF interpreter */
-    interp = (char *)main_binary_map.l_addr + main_binary_map.l_interp;
+    if (interp == NULL)
+        interp = (char *)main_binary_map.l_addr + main_binary_map.l_interp;
     map_so_lib( interp, &ld_so_map );

     /* store pointer to the preload info into the appropriate main
binary variable */