[RFA/win32] Problem storing result of GetProcAddress

[RFA/win32] Problem storing result of GetProcAddress

[Joel Brobecker]

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Hello,

GetProcAddress returns a FARPROC, but the variables that we use to
store the result that GetProcAddress returned is typically defined as:

    static BOOL WINAPI (*GetModuleFileNameExA) (HANDLE, HMODULE *, DWORD, LPDWORD);

I cannot define GetModuleFileNameExA as a FARPROC, as FARPROC is a
generic type that does not have the correct profile for our function.
If the function was defined as a FARPROC, we'd have problems calling
the functions, since the number of args and the return value would
not match.

For now, the laziest way of dealing the problem was to cast the resut
to "void *", which shouldn't cause any problem on Windows. Alternatively,
we can define a function pointer type for each of the functions we import
and then cast the result to that type.

2009-01-07  Joel Brobecker  <brobecker@adacore.com>

        * win32-nat.c (has_detach_ability, set_process_privilege):
        Cast the result of GetProcAddress to (void *) to avoid
        a compilation warning.

Tested on x86-windows. Note that this depends on one of my previous
patches that renames certain global variables:

    | * win32-nat.c (kernel32_DebugSetProcessKillOnExit): Renames
    | DebugSetProcessKillOnExit.  Update all uses in this file.
    | (kernel32_DebugActiveProcessStop): Renames DebugActiveProcessStop.
    | Update all uses in this file.

OK to apply?

Thanks,
-- 
Joel

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diff --git a/gdb/win32-nat.c b/gdb/win32-nat.c
index 1b15dfb..5300731 100644
--- a/gdb/win32-nat.c
+++ b/gdb/win32-nat.c
@@ -1600,11 +1600,11 @@ has_detach_ability (void)
   if (kernel32)
     {
       if (!kernel32_DebugSetProcessKillOnExit)
-	kernel32_DebugSetProcessKillOnExit = GetProcAddress (kernel32,
-						 "DebugSetProcessKillOnExit");
+	kernel32_DebugSetProcessKillOnExit =
+	  (void *) GetProcAddress (kernel32, "DebugSetProcessKillOnExit");
       if (!kernel32_DebugActiveProcessStop)
-	kernel32_DebugActiveProcessStop = GetProcAddress (kernel32,
-						 "DebugActiveProcessStop");
+	kernel32_DebugActiveProcessStop =
+	  (void *) GetProcAddress (kernel32, "DebugActiveProcessStop");
       if (kernel32_DebugSetProcessKillOnExit
 	  && kernel32_DebugActiveProcessStop)
 	return 1;
@@ -1641,13 +1641,14 @@ set_process_privilege (const char *privilege, BOOL enable)
       if (!(advapi32 = LoadLibrary ("advapi32.dll")))
 	goto out;
       if (!OpenProcessToken)
-	OpenProcessToken = GetProcAddress (advapi32, "OpenProcessToken");
+	OpenProcessToken =
+          (void *) GetProcAddress (advapi32, "OpenProcessToken");
       if (!LookupPrivilegeValue)
-	LookupPrivilegeValue = GetProcAddress (advapi32,
-					       "LookupPrivilegeValueA");
+	LookupPrivilegeValue =
+          (void *) GetProcAddress (advapi32, "LookupPrivilegeValueA");
       if (!AdjustTokenPrivileges)
-	AdjustTokenPrivileges = GetProcAddress (advapi32,
-						"AdjustTokenPrivileges");
+	AdjustTokenPrivileges =
+          (void *) GetProcAddress (advapi32, "AdjustTokenPrivileges");
       if (!OpenProcessToken || !LookupPrivilegeValue || !AdjustTokenPrivileges)
 	{
 	  advapi32 = NULL;

Re: [RFA/win32] Problem storing result of GetProcAddress

[Christopher Faylor]

On Wed, Jan 07, 2009 at 03:43:22PM +0400, Joel Brobecker wrote:
>2009-01-07  Joel Brobecker  <brobecker@adacore.com>
>
>        * win32-nat.c (has_detach_ability, set_process_privilege):
>        Cast the result of GetProcAddress to (void *) to avoid
>        a compilation warning.
>
>Tested on x86-windows. Note that this depends on one of my previous
>patches that renames certain global variables:
>
>    | * win32-nat.c (kernel32_DebugSetProcessKillOnExit): Renames
>    | DebugSetProcessKillOnExit.  Update all uses in this file.
>    | (kernel32_DebugActiveProcessStop): Renames DebugActiveProcessStop.
>    | Update all uses in this file.
>
>OK to apply?

Yes.  I guess that means that the rename to prefix kernel32_ is approved
too but I'd appreciate it if you would universally add the kernel32_ prefix
to everything that is dynamically derived from kernel32.

cgf

Re: [RFA/win32] Problem storing result of GetProcAddress

[Joel Brobecker]

> >2009-01-07  Joel Brobecker  <brobecker@adacore.com>
> >
> >        * win32-nat.c (has_detach_ability, set_process_privilege):
> >        Cast the result of GetProcAddress to (void *) to avoid
> >        a compilation warning.
>
> Yes.

Thank you! Checked in.

-- 
Joel