[PATCH 0/1] Load system libraries the recommended way on Windows

Johannes Schindelin via GitGitGadget· Oct 23, 2018, 10:51 UTC · lore

The search order for DLLs on Windows is a bit funny, and for system libraries, it is recommended to use a strict search path.

In practice, this should not make a difference, as the library has been loaded into memory already, and therefore the LoadLibrary() call would just return the handle instead of loading the library again.

Johannes Schindelin (1):
  mingw: load system libraries the recommended way

 compat/mingw.c                                      | 3 ++-
 contrib/credential/wincred/git-credential-wincred.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

base-commit: c4df23f7927d8d00e666a3c8d1b3375f1dc8a3c1
Published-As: https://github.com/gitgitgadget/git/releases/tags/pr-55%2Fdscho%2Fmingw-load-sys-dll-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-55/dscho/mingw-load-sys-dll-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/55

-- 
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Johannes Schindelin via GitGitGadget· Oct 23, 2018, 10:51 UTC · re: Johannes Schindelin via GitGitGadget · lore

[PATCH 1/1] mingw: load system libraries the recommended way

From: Johannes Schindelin <johannes.schindelin@gmx.de>

When we access IPv6-related functions, we load the corresponding system library using the `LoadLibrary()` function, which is not the recommended way to load system libraries.

In practice, it does not make a difference: the `ws2_32.dll` library containing the IPv6 functions is already loaded into memory, so LoadLibrary() simply reuses the already-loaded library.

Still, recommended way is recommended way, so let's use that instead.

While at it, also adjust the code in contrib/ that loads system libraries.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c                                      | 3 ++-
 contrib/credential/wincred/git-credential-wincred.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

Show changes to 2 files +4 −2

compat/mingw.c, contrib/credential/wincred/git-credential-wincred.c

diff --git a/compat/mingw.c b/compat/mingw.c
index 18caf2196..9fd7db571 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1577,7 +1577,8 @@ static void ensure_socket_initialization(void)
 			WSAGetLastError());
 
 	for (name = libraries; *name; name++) {
-		ipv6_dll = LoadLibrary(*name);
+		ipv6_dll = LoadLibraryExA(*name, NULL,
+					  LOAD_LIBRARY_SEARCH_SYSTEM32);
 		if (!ipv6_dll)
 			continue;
 
diff --git a/contrib/credential/wincred/git-credential-wincred.c b/contrib/credential/wincred/git-credential-wincred.c
index 86518cd93..5bdad41de 100644
--- a/contrib/credential/wincred/git-credential-wincred.c
+++ b/contrib/credential/wincred/git-credential-wincred.c
@@ -75,7 +75,8 @@ static CredDeleteWT CredDeleteW;
 static void load_cred_funcs(void)
 {
 	/* load DLLs */
-	advapi = LoadLibrary("advapi32.dll");
+	advapi = LoadLibraryExA("advapi32.dll", NULL,
+				LOAD_LIBRARY_SEARCH_SYSTEM32);
 	if (!advapi)
 		die("failed to load advapi32.dll");

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patchLoad system libraries the recommended way on Windows