file, but you are not obligated to do so. If you do not wish to do
so, delete this exception statement from your version. */
-/* #### Someone please document what these functions do! */
-
#include <config.h>
#include <stdio.h>
FreeConsole ();
}
+/* Construct the name for a named section (a.k.a. `file mapping') object.
+ The returned string is dynamically allocated and needs to be xfree()'d. */
+static char *
+make_section_name (DWORD pid)
+{
+ return aprintf ("gnu_wget_fake_fork_%lu", pid);
+}
+
+/* This structure is used to hold all the data that is exchanged between
+ parent and child. */
+struct fake_fork_info
+{
+ HANDLE event;
+ int changedp;
+ char lfilename[MAX_PATH + 1];
+};
+
+/* Determines if we are the child and if so performs the child logic.
+ Return values:
+ < 0 error
+ 0 parent
+ > 0 child
+*/
+static int
+fake_fork_child (void)
+{
+ HANDLE section, event;
+ struct fake_fork_info *info;
+ char *name;
+ DWORD le;
+
+ name = make_section_name (GetCurrentProcessId ());
+ section = OpenFileMapping (FILE_MAP_WRITE, FALSE, name);
+ le = GetLastError ();
+ xfree (name);
+ if (!section)
+ {
+ if (le == ERROR_FILE_NOT_FOUND)
+ return 0; /* Section object does not exist; we are the parent. */
+ else
+ return -1;
+ }
+
+ info = MapViewOfFile (section, FILE_MAP_WRITE, 0, 0, 0);
+ if (!info)
+ {
+ CloseHandle (section);
+ return -1;
+ }
+
+ event = info->event;
+
+ if (!opt.lfilename)
+ {
+ opt.lfilename = unique_name (DEFAULT_LOGFILE, 0);
+ info->changedp = 1;
+ strncpy (info->lfilename, opt.lfilename, sizeof (info->lfilename));
+ info->lfilename[sizeof (info->lfilename) - 1] = '\0';
+ }
+ else
+ info->changedp = 0;
+
+ UnmapViewOfFile (info);
+ CloseHandle (section);
+
+ /* Inform the parent that we've done our part. */
+ if (!SetEvent (event))
+ return -1;
+
+ CloseHandle (event);
+ return 1; /* We are the child. */
+}
+
+
+static void
+fake_fork (void)
+{
+ char *cmdline, *args;
+ char exe[MAX_PATH + 1];
+ DWORD exe_len, le;
+ SECURITY_ATTRIBUTES sa;
+ HANDLE section, event, h[2];
+ STARTUPINFO si;
+ PROCESS_INFORMATION pi;
+ struct fake_fork_info *info;
+ char *name;
+ BOOL rv;
+
+ event = section = pi.hProcess = pi.hThread = NULL;
+
+ /* Get command line arguments to pass to the child process.
+ We need to skip the name of the command (what amounts to argv[0]). */
+ cmdline = GetCommandLine ();
+ if (*cmdline == '"')
+ {
+ args = strchr (cmdline + 1, '"');
+ if (args)
+ ++args;
+ }
+ else
+ args = strchr (cmdline, ' ');
+
+ /* It's ok if args is NULL, that would mean there were no arguments
+ after the command name. As it is now though, we would never get here
+ if that were true. */
+
+ /* Get the fully qualified name of our executable. This is more reliable
+ than using argv[0]. */
+ exe_len = GetModuleFileName (GetModuleHandle (NULL), exe, sizeof (exe));
+ if (!exe_len || (exe_len >= sizeof (exe)))
+ return;
+
+ sa.nLength = sizeof (sa);
+ sa.lpSecurityDescriptor = NULL;
+ sa.bInheritHandle = TRUE;
+
+ /* Create an anonymous inheritable event object that starts out
+ non-signaled. */
+ event = CreateEvent (&sa, FALSE, FALSE, NULL);
+ if (!event)
+ return;
+
+ /* Creat the child process detached form the current console and in a
+ suspended state. */
+ memset (&si, 0, sizeof (si));
+ si.cb = sizeof (si);
+ rv = CreateProcess (exe, args, NULL, NULL, TRUE, CREATE_SUSPENDED |
+ DETACHED_PROCESS, NULL, NULL, &si, &pi);
+ if (!rv)
+ goto cleanup;
+
+ /* Create a named section object with a name based on the process id of
+ the child. */
+ name = make_section_name (pi.dwProcessId);
+ section =
+ CreateFileMapping (INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0,
+ sizeof (struct fake_fork_info), name);
+ le = GetLastError();
+ xfree (name);
+ /* Fail if the section object already exists (should not happen). */
+ if (!section || (le == ERROR_ALREADY_EXISTS))
+ {
+ rv = FALSE;
+ goto cleanup;
+ }
+
+ /* Copy the event handle into the section object. */
+ info = MapViewOfFile (section, FILE_MAP_WRITE, 0, 0, 0);
+ if (!info)
+ {
+ rv = FALSE;
+ goto cleanup;
+ }
+
+ info->event = event;
+
+ UnmapViewOfFile (info);
+
+ /* Start the child process. */
+ rv = ResumeThread (pi.hThread);
+ if (!rv)
+ {
+ TerminateProcess (pi.hProcess, (DWORD) -1);
+ goto cleanup;
+ }
+
+ /* Wait for the child to signal to us that it has done its part. If it
+ terminates before signaling us it's an error. */
+
+ h[0] = event;
+ h[1] = pi.hProcess;
+ rv = WAIT_OBJECT_0 == WaitForMultipleObjects (2, h, FALSE, 5 * 60 * 1000);
+ if (!rv)
+ goto cleanup;
+
+ info = MapViewOfFile (section, FILE_MAP_READ, 0, 0, 0);
+ if (!info)
+ {
+ rv = FALSE;
+ goto cleanup;
+ }
+
+ /* Ensure string is properly terminated. */
+ if (info->changedp &&
+ !memchr (info->lfilename, '\0', sizeof (info->lfilename)))
+ {
+ rv = FALSE;
+ goto cleanup;
+ }
+
+ printf (_("Continuing in background, pid %lu.\n"), pi.dwProcessId);
+ if (info->changedp)
+ printf (_("Output will be written to `%s'.\n"), info->lfilename);
+
+ UnmapViewOfFile (info);
+
+cleanup:
+
+ if (event)
+ CloseHandle (event);
+ if (section)
+ CloseHandle (section);
+ if (pi.hThread)
+ CloseHandle (pi.hThread);
+ if (pi.hProcess)
+ CloseHandle (pi.hProcess);
+
+ /* We're the parent. If all is well, terminate. */
+ if (rv)
+ exit (0);
+
+ /* We failed, return. */
+}
+
void
fork_to_background (void)
{
- ws_hangup ("fork");
+ int rv;
+
+ rv = fake_fork_child ();
+ if (rv < 0)
+ {
+ fprintf (stderr, "fake_fork_child() failed\n");
+ abort ();
+ }
+ else if (rv == 0)
+ {
+ /* We're the parent. */
+ fake_fork ();
+ /* If fake_fork() returns, it failed. */
+ fprintf (stderr, "fake_fork() failed\n");
+ abort ();
+ }
+ /* If we get here, we're the child. */
}
static BOOL WINAPI
projects / wget / commitdiff