On Sun, Oct 10, 2010 at 9:40 PM, Eric Sunshine <ericsunshine@xxxxxxxxx> wrote:
> On 10/10/2010 9:20 AM, Erik Faye-Lund wrote:
>>
>> From: Mike Pape<dotzenlabs@xxxxxxxxx>
>>
>> git-daemon requires some socket-functionality that is not yet
>> supported in the Windows-port. This patch adds said functionality,
>> and makes sure WSAStartup gets called by socket(), since it is the
>> first network-call in git-daemon. In addition, a check is added to
>> prevent WSAStartup (and WSACleanup, though atexit) from being
>> called more than once, since git-daemon calls both socket() and
>> gethostbyname().
>>
>> Signed-off-by: Mike Pape<dotzenlabs@xxxxxxxxx>
>> Signed-off-by: Erik Faye-Lund<kusmabite@xxxxxxxxx>
>> ---
>> diff --git a/compat/mingw.c b/compat/mingw.c
>> index 6590f33..563ef1f 100644
>> --- a/compat/mingw.c
>> +++ b/compat/mingw.c
>> +#undef accept
>> +int mingw_accept(int sockfd1, struct sockaddr *sa, socklen_t *sz)
>> +{
>> + int sockfd2;
>> +
>> + SOCKET s1 = (SOCKET)_get_osfhandle(sockfd1);
>> + SOCKET s2 = accept(s1, sa, sz);
>> +
>> + /* convert into a file descriptor */
>> + if ((sockfd2 = _open_osfhandle(s2, O_RDWR|O_BINARY))< 0) {
>> + closesocket(s2);
>> + return error("unable to make a socket file descriptor:
>> %s",
>> + strerror(errno));
>
> Is 'errno' from _open_osfhandle() still valid when handed to strerror() or
> has it been clobbered by closesocket()?
>
> Corollary: Does _open_osfhandle() indeed set 'errno', or is it more
> appropriate to call WSAGetLastError()? (The documentation I read for
> _open_osfhandle() did not say anything about how to determine the reason for
> failure.)
>
_open_osfhandle seems to set both errno and the winsock-error.
closesocket() sets the winsock-error but not the CRT. I've just tested
with a very simple application:
---8<---
#include <winsock2.h>
#include <io.h>
#include <fcntl.h>
#include <stdio.h>
const char *win32_strerror(DWORD dw)
{
static char tmp[4096];
FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, dw,
MAKELANGID(LANG_NEUTRAL, SUBLANG_NEUTRAL),
tmp, sizeof(tmp), NULL);
return tmp;
}
int main()
{
WSADATA wsa = {0};
WSAStartup(MAKEWORD(2, 0), &wsa);
printf("errno: '%s'\nWSAGetLastError: '%s'\n",
strerror(errno), win32_strerror(WSAGetLastError()));
errno = 0;
_open_osfhandle(-1, O_RDWR | O_BINARY);
printf("errno: '%s'\nWSAGetLastError: '%s'\n",
strerror(errno), win32_strerror(WSAGetLastError()));
errno = 0;
closesocket(-1);
printf("errno: '%s'\nWSAGetLastError: '%s'\n",
strerror(errno), win32_strerror(WSAGetLastError()));
return 0;
}
---8<---
The output is:
---8<---
errno: 'Result too large'
WSAGetLastError: 'The operation completed successfully.
'
errno: 'Bad file descriptor'
WSAGetLastError: 'The handle is invalid.
'
errno: 'No error'
WSAGetLastError: 'An operation was attempted on something that is not a socket.
'
---8<---
So, it seems that WSAGetLastError() gets clobbered by closesocket(),
but not errno.
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