diff options
Diffstat (limited to 'winsup/cygwin/fork.cc')
| -rw-r--r-- | winsup/cygwin/fork.cc | 703 |
1 files changed, 0 insertions, 703 deletions
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc deleted file mode 100644 index 22076fc1d..000000000 --- a/winsup/cygwin/fork.cc +++ /dev/null @@ -1,703 +0,0 @@ -/* fork.cc - - Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006, - 2007, 2008, 2009, 2010, 2011, 2012 Red Hat, Inc. - -This file is part of Cygwin. - -This software is a copyrighted work licensed under the terms of the -Cygwin license. Please consult the file "CYGWIN_LICENSE" for -details. */ - -#include "winsup.h" -#include <stdio.h> -#include <unistd.h> -#include <stdlib.h> -#include "cygerrno.h" -#include "sigproc.h" -#include "pinfo.h" -#include "path.h" -#include "fhandler.h" -#include "dtable.h" -#include "cygheap.h" -#include "child_info.h" -#include "cygtls.h" -#include "tls_pbuf.h" -#include "dll_init.h" -#include "cygmalloc.h" -#include "ntdll.h" - -#define NPIDS_HELD 4 - -/* Timeout to wait for child to start, parent to init child, etc. */ -/* FIXME: Once things stabilize, bump up to a few minutes. */ -#define FORK_WAIT_TIMEOUT (300 * 1000) /* 300 seconds */ - -class frok -{ - bool load_dlls; - child_info_fork ch; - const char *errmsg; - int child_pid; - int this_errno; - HANDLE hchild; - int __stdcall parent (volatile char * volatile here); - int __stdcall child (volatile char * volatile here); - bool error (const char *fmt, ...); - friend int fork (); -}; - -static void -resume_child (HANDLE forker_finished) -{ - SetEvent (forker_finished); - debug_printf ("signalled child"); - return; -} - -/* Notify parent that it is time for the next step. */ -static void __stdcall -sync_with_parent (const char *s, bool hang_self) -{ - debug_printf ("signalling parent: %s", s); - fork_info->ready (false); - if (hang_self) - { - HANDLE h = fork_info->forker_finished; - /* Wait for the parent to fill in our stack and heap. - Don't wait forever here. If our parent dies we don't want to clog - the system. If the wait fails, we really can't continue so exit. */ - DWORD psync_rc = WaitForSingleObject (h, FORK_WAIT_TIMEOUT); - debug_printf ("awake"); - switch (psync_rc) - { - case WAIT_TIMEOUT: - api_fatal ("WFSO timed out %s", s); - break; - case WAIT_FAILED: - if (GetLastError () == ERROR_INVALID_HANDLE && - WaitForSingleObject (fork_info->forker_finished, 1) != WAIT_FAILED) - break; - api_fatal ("WFSO failed %s, fork_finished %p, %E", s, - fork_info->forker_finished); - break; - default: - debug_printf ("no problems"); - break; - } - } -} - -bool -frok::error (const char *fmt, ...) -{ - DWORD exit_code = ch.exit_code; - if (!exit_code && hchild) - { - exit_code = ch.proc_retry (hchild); - if (!exit_code) - return false; - } - if (exit_code != EXITCODE_FORK_FAILED) - { - va_list ap; - static char buf[NT_MAX_PATH + 256]; - va_start (ap, fmt); - __small_vsprintf (buf, fmt, ap); - errmsg = buf; - } - return true; -} - -/* Set up a pipe which will track the life of a "pid" through - even after we've exec'ed. */ -void -child_info::prefork (bool detached) -{ - if (!detached) - { - if (!CreatePipe (&rd_proc_pipe, &wr_proc_pipe, &sec_none_nih, 16)) - api_fatal ("prefork: couldn't create pipe process tracker%E"); - - if (!SetHandleInformation (wr_proc_pipe, HANDLE_FLAG_INHERIT, - HANDLE_FLAG_INHERIT)) - api_fatal ("prefork: couldn't set process pipe(%p) inherit state, %E", - wr_proc_pipe); - ProtectHandle1 (rd_proc_pipe, rd_proc_pipe); - ProtectHandle1 (wr_proc_pipe, wr_proc_pipe); - } -} - -int __stdcall -frok::child (volatile char * volatile here) -{ - HANDLE& hParent = ch.parent; - extern void fixup_hooks_after_fork (); - extern void fixup_timers_after_fork (); - - /* NOTE: Logically this belongs in dll_list::load_after_fork, but by - doing it here, before the first sync_with_parent, we can exploit - the existing retry mechanism in hopes of getting a more favorable - address space layout next time. */ - dlls.reserve_space (); - - sync_with_parent ("after longjmp", true); - debug_printf ("child is running. pid %d, ppid %d, stack here %p", - myself->pid, myself->ppid, __builtin_frame_address (0)); - sigproc_printf ("hParent %p, load_dlls %d", hParent, load_dlls); - - /* If we've played with the stack, stacksize != 0. That means that - fork() was invoked from other than the main thread. Make sure that - the threadinfo information is properly set up. */ - if (fork_info->stackaddr) - { - _main_tls = &_my_tls; - _main_tls->init_thread (NULL, NULL); - _main_tls->local_clib = *_impure_ptr; - _impure_ptr = &_main_tls->local_clib; - } - - set_cygwin_privileges (hProcToken); - clear_procimptoken (); - cygheap->user.reimpersonate (); - -#ifdef DEBUGGING - if (GetEnvironmentVariableA ("FORKDEBUG", NULL, 0)) - try_to_debug (); - char buf[80]; - /* This is useful for debugging fork problems. Use gdb to attach to - the pid reported here. */ - if (GetEnvironmentVariableA ("CYGWIN_FORK_SLEEP", buf, sizeof (buf))) - { - small_printf ("Sleeping %d after fork, pid %u\n", atoi (buf), GetCurrentProcessId ()); - Sleep (atoi (buf)); - } -#endif - - MALLOC_CHECK; - - /* Incredible but true: If we use sockets and SYSV IPC shared memory, - there's a good chance that a duplicated socket in the child occupies - memory which is needed to duplicate shared memory from the parent - process, if the shared memory hasn't been duplicated already. - The same goes very likely for "normal" mmap shared memory, too, but - with SYSV IPC it was the first time observed. So, *never* fixup - fdtab before fixing up shared memory. */ - if (fixup_shms_after_fork ()) - api_fatal ("recreate_shm areas after fork failed"); - - MALLOC_CHECK; - - /* If we haven't dynamically loaded any dlls, just signal - the parent. Otherwise, load all the dlls, tell the parent - that we're done, and wait for the parent to fill in the. - loaded dlls' data/bss. */ - if (!load_dlls) - { - cygheap->fdtab.fixup_after_fork (hParent); - sync_with_parent ("performed fork fixup", false); - } - else - { - dlls.load_after_fork (hParent); - cygheap->fdtab.fixup_after_fork (hParent); - sync_with_parent ("loaded dlls", true); - } - - init_console_handler (myself->ctty > 0); - ForceCloseHandle1 (fork_info->forker_finished, forker_finished); - - pthread::atforkchild (); - fixup_timers_after_fork (); - cygbench ("fork-child"); - ld_preload (); - fixup_hooks_after_fork (); - _my_tls.fixup_after_fork (); - /* Clear this or the destructor will close them. In the case of - rd_proc_pipe that would be an invalid handle. In the case of - wr_proc_pipe it would be == my_wr_proc_pipe. Both would be bad. */ - ch.rd_proc_pipe = ch.wr_proc_pipe = NULL; - cygwin_finished_initializing = true; - return 0; -} - -#define NO_SLOW_PID_REUSE -#ifndef NO_SLOW_PID_REUSE -static void -slow_pid_reuse (HANDLE h) -{ - static NO_COPY HANDLE last_fork_procs[NPIDS_HELD]; - static NO_COPY unsigned nfork_procs; - - if (nfork_procs >= (sizeof (last_fork_procs) / sizeof (last_fork_procs [0]))) - nfork_procs = 0; - /* Keep a list of handles to child processes sitting around to prevent - Windows from reusing the same pid n times in a row. Having the same pids - close in succesion confuses bash. Keeping a handle open will stop - windows from reusing the same pid. */ - if (last_fork_procs[nfork_procs]) - ForceCloseHandle1 (last_fork_procs[nfork_procs], fork_stupidity); - if (DuplicateHandle (GetCurrentProcess (), h, - GetCurrentProcess (), &last_fork_procs[nfork_procs], - 0, FALSE, DUPLICATE_SAME_ACCESS)) - ProtectHandle1 (last_fork_procs[nfork_procs], fork_stupidity); - else - { - last_fork_procs[nfork_procs] = NULL; - system_printf ("couldn't create last_fork_proc, %E"); - } - nfork_procs++; -} -#endif - -int __stdcall -frok::parent (volatile char * volatile stack_here) -{ - HANDLE forker_finished; - DWORD rc; - child_pid = -1; - this_errno = 0; - bool fix_impersonation = false; - pinfo child; - - int c_flags = GetPriorityClass (GetCurrentProcess ()); - debug_printf ("priority class %d", c_flags); - - errmsg = NULL; - hchild = NULL; - - /* If we don't have a console, then don't create a console for the - child either. */ - HANDLE console_handle = CreateFile ("CONOUT$", GENERIC_WRITE, - FILE_SHARE_READ | FILE_SHARE_WRITE, - &sec_none_nih, OPEN_EXISTING, - FILE_ATTRIBUTE_NORMAL, NULL); - - if (console_handle != INVALID_HANDLE_VALUE) - CloseHandle (console_handle); - else - c_flags |= DETACHED_PROCESS; - - /* Some file types (currently only sockets) need extra effort in the - parent after CreateProcess and before copying the datastructures - to the child. So we have to start the child in suspend state, - unfortunately, to avoid a race condition. */ - if (cygheap->fdtab.need_fixup_before ()) - c_flags |= CREATE_SUSPENDED; - - /* Remember if we need to load dynamically linked dlls. - We do this here so that this information will be available - in the parent and, when the stack is copied, in the child. */ - load_dlls = dlls.reload_on_fork && dlls.loaded_dlls; - - forker_finished = CreateEvent (&sec_all, FALSE, FALSE, NULL); - if (forker_finished == NULL) - { - this_errno = geterrno_from_win_error (); - error ("unable to allocate forker_finished event"); - return -1; - } - - ProtectHandleINH (forker_finished); - - ch.forker_finished = forker_finished; - - ch.stackbottom = _tlsbase; - ch.stacktop = (void *) _tlstop; - ch.stackaddr = 0; - ch.guardsize = 0; - if (&_my_tls != _main_tls) - { - /* We have not been started from the main thread. Fetch the - information required to set up the thread stack identically - in the child. */ - PTEB teb = NtCurrentTeb (); - if (!teb->DeallocationStack) - { - /* Pthread with application-provided stack. Don't set up a - PAGE_GUARD page. guardsize == -1 is used in alloc_stack_hard_way - to recognize this type of stack. */ - ch.stackaddr = _my_tls.tid->attr.stackaddr; - ch.guardsize = (size_t) -1; - } - else - { - ch.stackaddr = teb->DeallocationStack; - /* If it's a pthread, fetch guardsize from thread attributes. */ - if (_my_tls.tid) - ch.guardsize = _my_tls.tid->attr.guardsize; - } - } - debug_printf ("stack - bottom %p, top %p, addr %p, guardsize %p", - ch.stackbottom, ch.stacktop, ch.stackaddr, ch.guardsize); - - PROCESS_INFORMATION pi; - STARTUPINFOW si; - - memset (&si, 0, sizeof (si)); - si.cb = sizeof si; - - si.lpReserved2 = (LPBYTE) &ch; - si.cbReserved2 = sizeof (ch); - - syscall_printf ("CreateProcessW (%W, %W, 0, 0, 1, %p, 0, 0, %p, %p)", - myself->progname, myself->progname, c_flags, &si, &pi); - bool locked = __malloc_lock (); - time_t start_time = time (NULL); - - /* Remove impersonation */ - cygheap->user.deimpersonate (); - fix_impersonation = true; - ch.refresh_cygheap (); - ch.prefork (); /* set up process tracking pipes. */ - - while (1) - { - hchild = NULL; - rc = CreateProcessW (myself->progname, /* image to run */ - myself->progname, /* what we send in arg0 */ - &sec_none_nih, - &sec_none_nih, - TRUE, /* inherit handles from parent */ - c_flags, - NULL, /* environment filled in later */ - 0, /* use current drive/directory */ - &si, - &pi); - - if (rc) - debug_printf ("forked pid %u", pi.dwProcessId); - else - { - this_errno = geterrno_from_win_error (); - error ("CreateProcessW failed for '%W'", myself->progname); - memset (&pi, 0, sizeof (pi)); - goto cleanup; - } - - if (cygheap->fdtab.need_fixup_before ()) - { - cygheap->fdtab.fixup_before_fork (pi.dwProcessId); - ResumeThread (pi.hThread); - } - - CloseHandle (pi.hThread); - hchild = pi.hProcess; - - /* Protect the handle but name it similarly to the way it will - be called in subproc handling. */ - ProtectHandle1 (hchild, childhProc); - - strace.write_childpid (pi.dwProcessId); - - /* Wait for subproc to initialize itself. */ - if (!ch.sync (pi.dwProcessId, hchild, FORK_WAIT_TIMEOUT)) - { - if (!error ("forked process %u died unexpectedly, retry %d, exit code %d", - pi.dwProcessId, ch.retry, ch.exit_code)) - continue; - this_errno = EAGAIN; - goto cleanup; - } - break; - } - - /* Restore impersonation */ - cygheap->user.reimpersonate (); - fix_impersonation = false; - - child_pid = cygwin_pid (pi.dwProcessId); - child.init (child_pid, 1, NULL); - - if (!child) - { - this_errno = get_errno () == ENOMEM ? ENOMEM : EAGAIN; - syscall_printf ("pinfo failed"); - goto cleanup; - } - - child->start_time = start_time; /* Register child's starting time. */ - child->nice = myself->nice; - - /* Initialize things that are done later in dll_crt0_1 that aren't done - for the forkee. */ - wcscpy (child->progname, myself->progname); - - /* Fill in fields in the child's process table entry. */ - child->dwProcessId = pi.dwProcessId; - child.hProcess = hchild; - ch.postfork (child); - - /* Hopefully, this will succeed. The alternative to doing things this - way is to reserve space prior to calling CreateProcess and then fill - it in afterwards. This requires more bookkeeping than I like, though, - so we'll just do it the easy way. So, terminate any child process if - we can't actually record the pid in the internal table. */ - if (!child.remember (false)) - { - TerminateProcess (hchild, 1); - this_errno = EAGAIN; -#ifdef DEBUGGING0 - error ("child remember failed"); -#endif - goto cleanup; - } - -#ifndef NO_SLOW_PID_REUSE - slow_pid_reuse (hchild); -#endif - - /* CHILD IS STOPPED */ - debug_printf ("child is alive (but stopped)"); - - - /* Initialize, in order: stack, dll data, dll bss. - data, bss, heap were done earlier (in dcrt0.cc) - Note: variables marked as NO_COPY will not be copied since they are - placed in a protected segment. */ - - MALLOC_CHECK; - const void *impure_beg; - const void *impure_end; - const char *impure; - if (&_my_tls == _main_tls) - impure_beg = impure_end = impure = NULL; - else - { - impure = "impure"; - impure_beg = _impure_ptr; - impure_end = _impure_ptr + 1; - } - rc = child_copy (hchild, true, - "stack", stack_here, ch.stackbottom, - impure, impure_beg, impure_end, - NULL); - - __malloc_unlock (); - locked = false; - MALLOC_CHECK; - if (!rc) - { - this_errno = get_errno (); - error ("pid %u, exitval %p", pi.dwProcessId, ch.exit_code); - goto cleanup; - } - - /* Now fill data/bss of any DLLs that were linked into the program. */ - for (dll *d = dlls.istart (DLL_LINK); d; d = dlls.inext ()) - { - debug_printf ("copying data/bss of a linked dll"); - if (!child_copy (hchild, true, - "linked dll data", d->p.data_start, d->p.data_end, - "linked dll bss", d->p.bss_start, d->p.bss_end, - NULL)) - { - this_errno = get_errno (); - error ("couldn't copy linked dll data/bss"); - goto cleanup; - } - } - - /* Start thread, and then wait for it to reload dlls. */ - resume_child (forker_finished); - if (!ch.sync (child->pid, hchild, FORK_WAIT_TIMEOUT)) - { - this_errno = EAGAIN; - error ("died waiting for dll loading"); - goto cleanup; - } - - /* If DLLs were loaded in the parent, then the child has reloaded all - of them and is now waiting to have all of the individual data and - bss sections filled in. */ - if (load_dlls) - { - /* CHILD IS STOPPED */ - /* write memory of reloaded dlls */ - for (dll *d = dlls.istart (DLL_LOAD); d; d = dlls.inext ()) - { - debug_printf ("copying data/bss for a loaded dll"); - if (!child_copy (hchild, true, - "loaded dll data", d->p.data_start, d->p.data_end, - "loaded dll bss", d->p.bss_start, d->p.bss_end, - NULL)) - { - this_errno = get_errno (); -#ifdef DEBUGGING - error ("copying data/bss for a loaded dll"); -#endif - goto cleanup; - } - } - /* Start the child up again. */ - resume_child (forker_finished); - } - - ForceCloseHandle (forker_finished); - forker_finished = NULL; - - return child_pid; - -/* Common cleanup code for failure cases */ -cleanup: - if (fix_impersonation) - cygheap->user.reimpersonate (); - if (locked) - __malloc_unlock (); - - /* Remember to de-allocate the fd table. */ - if (hchild && !child.hProcess) - ForceCloseHandle1 (hchild, childhProc); - if (forker_finished) - ForceCloseHandle (forker_finished); - debug_printf ("returning -1"); - return -1; -} - -extern "C" int -fork () -{ - frok grouped; - - debug_printf ("entering"); - grouped.load_dlls = 0; - - int res; - bool ischild = false; - - myself->set_has_pgid_children (); - - if (grouped.ch.parent == NULL) - return -1; - if (grouped.ch.subproc_ready == NULL) - { - system_printf ("unable to allocate subproc_ready event, %E"); - return -1; - } - - { - hold_everything held_everything (ischild); - /* This tmp_pathbuf constructor is required here because the below setjmp - magic will otherwise not restore the original buffer count values in - the thread-local storage. A process forking too deeply will run into - the problem to be out of temporary TLS path buffers. */ - tmp_pathbuf tp; - - if (!held_everything) - { - if (exit_state) - Sleep (INFINITE); - set_errno (EAGAIN); - return -1; - } - - /* Put the dll list in topological dependency ordering, in - hopes that the child will have a better shot at loading dlls - properly if it only has to deal with one at a time. */ - dlls.topsort (); - - ischild = !!setjmp (grouped.ch.jmp); - - volatile char * volatile esp; - __asm__ volatile ("movl %%esp,%0": "=r" (esp)); - - if (!ischild) - res = grouped.parent (esp); - else - { - res = grouped.child (esp); - in_forkee = false; - ischild = true; /* might have been reset by fork mem copy */ - } - } - - MALLOC_CHECK; - if (ischild) - { - myself->process_state |= PID_ACTIVE; - myself->process_state &= ~(PID_INITIALIZING | PID_EXITED | PID_REAPED); - } - else if (res < 0) - { - if (!grouped.errmsg) - syscall_printf ("fork failed - child pid %d, errno %d", grouped.child_pid, grouped.this_errno); - else - { - char buf[strlen (grouped.errmsg) + sizeof ("child %d - , errno 4294967295 ")]; - strcpy (buf, "child %d - "); - strcat (buf, grouped.errmsg); - strcat (buf, ", errno %d"); - system_printf (buf, grouped.child_pid, grouped.this_errno); - } - - set_errno (grouped.this_errno); - } - syscall_printf ("%R = fork()", res); - return res; -} -#ifdef DEBUGGING -void -fork_init () -{ -} -#endif /*DEBUGGING*/ - - -extern "C" int -vfork () -{ - debug_printf ("stub called"); - return fork (); -} - -/* Copy memory from one process to another. */ - -bool -child_copy (HANDLE hp, bool write, ...) -{ - va_list args; - va_start (args, write); - static const char *huh[] = {"read", "write"}; - - char *what; - while ((what = va_arg (args, char *))) - { - char *low = va_arg (args, char *); - char *high = va_arg (args, char *); - DWORD todo = high - low; - char *here; - - for (here = low; here < high; here += todo) - { - DWORD done = 0; - if (here + todo > high) - todo = high - here; - int res; - if (write) - res = WriteProcessMemory (hp, here, here, todo, &done); - else - res = ReadProcessMemory (hp, here, here, todo, &done); - debug_printf ("%s - hp %p low %p, high %p, res %d", what, hp, low, high, res); - if (!res || todo != done) - { - if (!res) - __seterrno (); - /* If this happens then there is a bug in our fork - implementation somewhere. */ - system_printf ("%s %s copy failed, %p..%p, done %d, windows pid %u, %E", - what, huh[write], low, high, done, myself->dwProcessId); - goto err; - } - } - } - - va_end (args); - debug_printf ("done"); - return true; - - err: - va_end (args); - TerminateProcess (hp, 1); - set_errno (EAGAIN); - return false; -} |