Magic-Mirror/gecko-dev
1
0
Fork 0
mirror of https://github.com/mozilla/gecko-dev.git synced 2024-10-12 21:05:36 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Evil fix for deadlock during synchronous http url loads...

Browse Source
This commit is contained in:
rpotts%netscape.com 1998-08-25 05:51:40 +00:00
parent 74eb63531e
commit cf4d8e6925
1 changed files with 65 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

65
network/module/nsNetService.cpp
View File

@ -44,6 +44,10 @@ MWContext *new_stub_context(URL_Struct *URL_s);
void free_stub_context(MWContext *window_id);
static void bam_exit_routine(URL_Struct *URL_s, int status, MWContext *window_id);
#if defined(XP_WIN)
nsresult PerformNastyWindowsAsyncDNSHack(URL_Struct* URL_s, nsIURL* aURL);
#endif /* XP_WIN */
extern "C" {
#include "fileurl.h"
#include "httpurl.h"
@ -350,6 +354,21 @@ nsresult nsNetlibService::OpenBlockingStream(nsIURL *aUrl,
goto loser;
}
#if defined(XP_WIN)
/*
* When opening a blocking HTTP stream, perform a synchronous DNS
* lookup now, to avoid netlib from doing an async lookup later
* and causing a deadlock!
*/
result = PerformNastyWindowsAsyncDNSHack(URL_s, aUrl);
if (NS_OK != result) {
NET_FreeURLStruct(URL_s);
pBlockingStream->Release();
pConn->Release();
goto loser;
}
#endif /* XP_WIN */
/*
* Mark the URL as background loading. This prevents many
* client upcall notifications...
@ -535,6 +554,52 @@ void nsNetlibService::NetPollSocketsCallback(nsITimer* aTimer, void* aClosure)
}
}
#if defined(XP_WIN)
/*
* This routine is used to avoid a (hopefully temporary) problem which netlib
* has when processing blocking HTTP streams.
*
* When ASYNC_DNS is enabled, all DNS lookups go through the main message pump,
* unfortunately, this is not possible when processing a blocking stream, so
* we deadlock :-(
*
* To avoid this deadlock, we synchronously resolve the hostname and store it
* in the little known IPAddressString field of the URL_Struct. This prevents
* netlib from doing an Async DNS lookup later...
*/
nsresult PerformNastyWindowsAsyncDNSHack(URL_Struct *URL_s, nsIURL* aURL)
{
PRHostEnt hpbuf;
char dbbuf[PR_NETDB_BUF_SIZE];
PRStatus err;
nsresult rv = NS_OK;
/* Only attempt to resolve the hostname for HTTP URLs... */
if (0 == PL_strcasecmp("http", aURL->GetProtocol())) {
/* Perform a synchronous DNS lookup... */
err = PR_GetHostByName(aURL->GetHost(), dbbuf, sizeof(dbbuf), &hpbuf);
if (PR_SUCCESS == err) {
int a,b,c,d;
unsigned char *pc;
pc = (unsigned char *) hpbuf.h_addr_list[0];
a = (int) *pc;
b = (int) *(++pc);
c = (int) *(++pc);
d = (int) *(++pc);
URL_s->IPAddressString = PR_smprintf("%d.%d.%d.%d", a,b,c,d);
}
/*
* If we fail to resolve a host on a HTTP connection, then abort the
* connection to prevent a deadlock...
*/
rv = NS_ERROR_FAILURE;
}
return rv;
}
#endif /* XP_WIN */
static nsNetlibService *gNetlibService = nsnull;