diff options
Diffstat (limited to 'winsup/cygwin/fork.cc')
| -rw-r--r-- | winsup/cygwin/fork.cc | 782 |
1 files changed, 0 insertions, 782 deletions
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc deleted file mode 100644 index 5a70c7b87..000000000 --- a/winsup/cygwin/fork.cc +++ /dev/null @@ -1,782 +0,0 @@ -/* fork.cc - - Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006, - 2007, 2008, 2009 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 "path.h" -#include "fhandler.h" -#include "dtable.h" -#include "sigproc.h" -#include "pinfo.h" -#include "cygheap.h" -#include "child_info.h" -#include "cygtls.h" -#include "tls_pbuf.h" -#include "dll_init.h" -#include "cygmalloc.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 *error; - int child_pid; - int this_errno; - int __stdcall parent (volatile char * volatile here); - int __stdcall child (volatile char * volatile here); - friend int fork (); -}; - -class lock_signals -{ - bool worked; -public: - lock_signals () - { - worked = sig_send (NULL, __SIGHOLD) == 0; - } - operator int () const - { - return worked; - } - void dont_bother () - { - worked = false; - } - ~lock_signals () - { - if (worked) - sig_send (NULL, __SIGNOHOLD); - } -}; - -class lock_pthread -{ - bool bother; -public: - lock_pthread (): bother (1) - { - pthread::atforkprepare (); - } - void dont_bother () - { - bother = false; - } - ~lock_pthread () - { - if (bother) - pthread::atforkparent (); - } -}; - -class hold_everything -{ -public: /* DELETEME*/ - bool& ischild; - /* Note the order of the locks below. It is important, - to avoid races, that the lock order be preserved. - - pthread is first because it serves as a master lock - against other forks being attempted while this one is active. - - signals is next to stop signal processing for the duration - of the fork. - - process is last. If it is put before signals, then a deadlock - could be introduced if the process attempts to exit due to a signal. */ - lock_pthread pthread; - lock_signals signals; - lock_process process; - -public: - hold_everything (bool& x): ischild (x) {} - operator int () const {return signals;} - - ~hold_everything() - { - if (ischild) - { - pthread.dont_bother (); - process.dont_bother (); - signals.dont_bother (); - } - } - -}; - -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; - } - } -} - -int __stdcall -frok::child (volatile char * volatile here) -{ - HANDLE& hParent = ch.parent; - extern void fixup_lockf_after_fork (); - extern void fixup_hooks_after_fork (); - extern void fixup_timers_after_fork (); - debug_printf ("child is running. pid %d, ppid %d, stack here %p", - myself->pid, myself->ppid, __builtin_frame_address (0)); - - sync_with_parent ("after longjmp", true); - 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->stacksize) - { - _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 (); - 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; - error = NULL; - this_errno = 0; - bool fix_impersonation = false; - pinfo child; - static char errbuf[NT_MAX_PATH + 256]; - - int c_flags = GetPriorityClass (GetCurrentProcess ()); - debug_printf ("priority class %d", c_flags); - - /* 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_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 *) stack_here; - ch.stacksize = (char *) ch.stackbottom - (char *) stack_here; - debug_printf ("stack - bottom %p, top %p, size %d", - ch.stackbottom, ch.stacktop, ch.stacksize); - - 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; - - while (1) - { - 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) - { - this_errno = geterrno_from_win_error (); - __small_sprintf (errbuf, "CreateProcessW failed for '%W'", myself->progname); - error = errbuf; - 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); - - /* Protect the handle but name it similarly to the way it will - be called in subproc handling. */ - ProtectHandle1 (pi.hProcess, childhProc); - - strace.write_childpid (ch, pi.dwProcessId); - - /* Wait for subproc to initialize itself. */ - if (!ch.sync (pi.dwProcessId, pi.hProcess, FORK_WAIT_TIMEOUT)) - { - DWORD exit_code = ch.proc_retry (pi.hProcess); - if (!exit_code) - continue; - this_errno = EAGAIN; - /* Not thread safe, but do we care? */ - __small_sprintf (errbuf, "died waiting for longjmp before initialization, " - "retry %d, exit code %p", ch.retry, exit_code); - error = errbuf; - 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; -#ifdef DEBUGGING - error = "pinfo failed"; -#else - syscall_printf ("pinfo failed"); -#endif - 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 = pi.hProcess; - - /* 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 (pi.hProcess, 1); - this_errno = EAGAIN; -#ifdef DEBUGGING0 - error = "child.remember failed"; -#endif - goto cleanup; - } - -#ifndef NO_SLOW_PID_REUSE - slow_pid_reuse (pi.hProcess); -#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 (pi.hProcess, true, - "stack", stack_here, ch.stackbottom, - impure, impure_beg, impure_end, - NULL); - - __malloc_unlock (); - locked = false; - MALLOC_CHECK; - if (!rc) - { - this_errno = get_errno (); - DWORD exit_code; - if (!GetExitCodeProcess (pi.hProcess, &exit_code)) - exit_code = 0xdeadbeef; - __small_sprintf (errbuf, "pid %u, exitval %p", pi.dwProcessId, exit_code); - error = errbuf; - 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 (pi.hProcess, 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 (); -#ifdef DEBUGGING - DWORD exit_code; - if (!GetExitCodeProcess (pi.hProcess, &exit_code)) - exit_code = 0xdeadbeef; - __small_sprintf (errbuf, "pid %u, exitval %p", pi.dwProcessId, exit_code); - error = errbuf; -#endif - goto cleanup; - } - } - - /* Start thread, and then wait for it to reload dlls. */ - resume_child (forker_finished); - if (!ch.sync (child->pid, pi.hProcess, 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 (pi.hProcess, 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 (pi.hProcess && !child.hProcess) - ForceCloseHandle1 (pi.hProcess, 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; - } - - 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); - 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); - } - else if (res < 0) - { - if (!grouped.error) - syscall_printf ("fork failed - child pid %d, errno %d", grouped.child_pid, grouped.this_errno); - else - { - char buf[strlen (grouped.error) + sizeof ("child %d - , errno 4294967295 ")]; - strcpy (buf, "child %d - "); - strcat (buf, grouped.error); - strcat (buf, ", errno %d"); - system_printf (buf, grouped.child_pid, grouped.this_errno); - } - - set_errno (grouped.this_errno); - } - syscall_printf ("%d = fork()", res); - return res; -} -#ifdef DEBUGGING -void -fork_init () -{ -} -#endif /*DEBUGGING*/ - -#ifdef NEWVFORK -/* Dummy function to force second assignment below to actually be - carried out */ -static vfork_save * -get_vfork_val () -{ - return vfork_storage.val (); -} -#endif - -extern "C" int -vfork () -{ -#ifndef NEWVFORK - debug_printf ("stub called"); - return fork (); -#else - vfork_save *vf = get_vfork_val (); - char **esp, **pp; - - if (vf == NULL) - vf = vfork_storage.create (); - else if (vf->pid) - return fork (); - - // FIXME the tls stuff could introduce a signal race if a child process - // exits quickly. - if (!setjmp (vf->j)) - { - vf->pid = -1; - __asm__ volatile ("movl %%esp,%0": "=r" (vf->vfork_esp):); - __asm__ volatile ("movl %%ebp,%0": "=r" (vf->vfork_ebp):); - for (pp = (char **) vf->frame, esp = vf->vfork_esp; - esp <= vf->vfork_ebp + 2; pp++, esp++) - *pp = *esp; - vf->ctty = myself->ctty; - vf->sid = myself->sid; - vf->pgid = myself->pgid; - cygheap->ctty_on_hold = cygheap->ctty; - vf->console_count = cygheap->console_count; - debug_printf ("cygheap->ctty_on_hold %p, cygheap->console_count %d", cygheap->ctty_on_hold, cygheap->console_count); - int res = cygheap->fdtab.vfork_child_dup () ? 0 : -1; - debug_printf ("%d = vfork()", res); - _my_tls.call_signal_handler (); // FIXME: racy - vf->tls = _my_tls; - return res; - } - - vf = get_vfork_val (); - - for (pp = (char **) vf->frame, esp = vf->vfork_esp; - esp <= vf->vfork_ebp + 2; pp++, esp++) - *esp = *pp; - - cygheap->fdtab.vfork_parent_restore (); - - myself->ctty = vf->ctty; - myself->sid = vf->sid; - myself->pgid = vf->pgid; - termios_printf ("cygheap->ctty %p, cygheap->ctty_on_hold %p", cygheap->ctty, cygheap->ctty_on_hold); - cygheap->console_count = vf->console_count; - - if (vf->pid < 0) - { - int exitval = vf->exitval; - vf->pid = 0; - if ((vf->pid = fork ()) == 0) - exit (exitval); - } - - int pid = vf->pid; - vf->pid = 0; - debug_printf ("exiting vfork, pid %d", pid); - sig_dispatch_pending (); - - _my_tls.call_signal_handler (); // FIXME: racy - _my_tls = vf->tls; - return pid; -#endif -} - -/* 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 = wincap.chunksize () ?: 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; -} |