diff options
Diffstat (limited to 'winsup/cygwin/fork.cc')
| -rw-r--r-- | winsup/cygwin/fork.cc | 745 |
1 files changed, 0 insertions, 745 deletions
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc deleted file mode 100644 index daca12109..000000000 --- a/winsup/cygwin/fork.cc +++ /dev/null @@ -1,745 +0,0 @@ -/* fork.cc - - Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002 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 <stdarg.h> -#include <errno.h> -#include "security.h" -#include "fhandler.h" -#include "path.h" -#include "dtable.h" -#include "cygerrno.h" -#include "sigproc.h" -#include "pinfo.h" -#include "cygheap.h" -#include "child_info.h" -#define NEED_VFORK -#include "perthread.h" -#include "perprocess.h" -#include "dll_init.h" -#include "sync.h" -#include "cygmalloc.h" - -#ifdef DEBUGGING -static int npid; -static int npid_max; -static pid_t fork_pids[100]; -#endif - -/* 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 */ - -#define dll_data_start &_data_start__ -#define dll_data_end &_data_end__ -#define dll_bss_start &_bss_start__ -#define dll_bss_end &_bss_end__ - -void -per_thread::set (void *s) -{ - if (s == PER_THREAD_FORK_CLEAR) - { - tls = TlsAlloc (); - s = NULL; - } - TlsSetValue (get_tls (), s); -} - -static void -stack_base (child_info_fork &ch) -{ - MEMORY_BASIC_INFORMATION m; - memset (&m, 0, sizeof m); - if (!VirtualQuery ((LPCVOID) &m, &m, sizeof m)) - system_printf ("couldn't get memory info, %E"); - - ch.stacktop = m.AllocationBase; - ch.stackbottom = (LPBYTE) m.BaseAddress + m.RegionSize; - ch.stacksize = (DWORD) ch.stackbottom - (DWORD) &m; - debug_printf ("bottom %p, top %p, stack %p, size %d, reserve %d", - ch.stackbottom, ch.stacktop, &m, ch.stacksize, - (DWORD) ch.stackbottom - (DWORD) ch.stacktop); -} - -/* Copy memory from parent to child. - The result is a boolean indicating success. */ - -static int -fork_copy (PROCESS_INFORMATION &pi, const char *what, ...) -{ - va_list args; - char *low; - int pass = 0; - - va_start (args, what); - - while ((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 = WriteProcessMemory (pi.hProcess, here, here, todo, &done); - debug_printf ("child handle %p, low %p, high %p, res %d", pi.hProcess, - 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 pass %d failed, %p..%p, done %d, windows pid %u, %E", - what, pass, low, high, done, pi.dwProcessId); - goto err; - } - } - - pass++; - } - - debug_printf ("done"); - return 1; - - err: - TerminateProcess (pi.hProcess, 1); - set_errno (EAGAIN); - return 0; -} - -/* Wait for child to finish what it's doing and signal us. - We don't want to wait forever here.If there's a problem somewhere - it'll hang the entire system (since all forks are mutex'd). If we - time out, set errno = EAGAIN and hope the app tries again. */ -static int -sync_with_child (PROCESS_INFORMATION &pi, HANDLE subproc_ready, - BOOL hang_child, const char *s) -{ - /* We also add the child process handle to the wait. If the child fails - to initialize (eg. because of a missing dll). Then this - handle will become signalled. This stops a *looong* timeout wait. - */ - HANDLE w4[2]; - - debug_printf ("waiting for child. reason: %s, hang_child %d", s, - hang_child); - w4[1] = pi.hProcess; - w4[0] = subproc_ready; - DWORD rc = WaitForMultipleObjects (2, w4, FALSE, FORK_WAIT_TIMEOUT); - - if (rc == WAIT_OBJECT_0 || - WaitForSingleObject (subproc_ready, 0) == WAIT_OBJECT_0) - /* That's ok */; - else if (rc == WAIT_FAILED || rc == WAIT_TIMEOUT) - { - if (rc != WAIT_FAILED) - system_printf ("WaitForMultipleObjects timed out"); - else - system_printf ("WaitForMultipleObjects failed, %E"); - set_errno (EAGAIN); - syscall_printf ("-1 = fork(), WaitForMultipleObjects failed"); - TerminateProcess (pi.hProcess, 1); - return 0; - } - else - { - /* Child died. Clean up and exit. */ - DWORD errcode; - GetExitCodeProcess (pi.hProcess, &errcode); - /* Fix me. This is not enough. The fork should not be considered - * to have failed if the process was essentially killed by a signal. - */ - if (errcode != STATUS_CONTROL_C_EXIT) - { - system_printf ("child %d(%p) died before initialization with status code %p", - pi.dwProcessId, pi.hProcess, errcode); - system_printf ("*** child state %s", s); -#ifdef DEBUGGING - abort (); -#endif - } - set_errno (EAGAIN); - syscall_printf ("Child died before subproc_ready signalled"); - return 0; - } - - debug_printf ("child signalled me"); - return 1; -} - -static int -resume_child (PROCESS_INFORMATION &pi, HANDLE forker_finished) -{ - SetEvent (forker_finished); - debug_printf ("signalled child"); - return 1; -} - -/* Notify parent that it is time for the next step. - Note that this has to be a macro since the parent may be messing with - our stack. */ -static void __stdcall -sync_with_parent (const char *s, bool hang_self) -{ - debug_printf ("signalling parent: %s", s); - /* Tell our parent we're waiting. */ - if (!SetEvent (fork_info->subproc_ready)) - api_fatal ("fork child - SetEvent for %s failed, %E", s); - 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 for %s", s); - break; - case WAIT_FAILED: - if (GetLastError () == ERROR_INVALID_HANDLE && - WaitForSingleObject (fork_info->forker_finished, 1) != WAIT_FAILED) - break; - api_fatal ("WFSO failed for %s, fork_finished %p, %E", s, - fork_info->forker_finished); - break; - default: - debug_printf ("no problems"); - break; - } - } -} - -static int __stdcall -fork_child (HANDLE& hParent, dll *&first_dll, bool& load_dlls) -{ - debug_printf ("child is running. pid %d, ppid %d, stack here %p", - myself->pid, myself->ppid, __builtin_frame_address (0)); - - /* Restore the inheritance state as in parent - Don't call setuid here! The flags are already set. */ - if (cygheap->user.impersonated) - { - debug_printf ("Impersonation of child, token: %d", cygheap->user.token); - if (cygheap->user.token == INVALID_HANDLE_VALUE) - RevertToSelf (); // probably not needed - else if (!ImpersonateLoggedOnUser (cygheap->user.token)) - system_printf ("Impersonate for forked child failed: %E"); - } - - sync_with_parent ("after longjmp.", TRUE); - sigproc_printf ("hParent %p, child 1 first_dll %p, load_dlls %d\n", hParent, - first_dll, load_dlls); - -#ifdef DEBUGGING - char c; - if (GetEnvironmentVariable ("FORKDEBUG", &c, 1)) - try_to_debug (); - char buf[80]; - /* This is useful for debugging fork problems. Use gdb to attach to - the pid reported here. */ - if (GetEnvironmentVariable ("CYGWIN_FORK_SLEEP", buf, sizeof (buf))) - { - small_printf ("Sleeping %d after fork, pid %u\n", atoi (buf), GetCurrentProcessId ()); - Sleep (atoi (buf)); - } -#endif - - /* If we've played with the stack, stacksize != 0. That means that - fork() was invoked from other than the main thread. Make sure that - when the "main" thread exits it calls do_exit, like a normal process. - Exit with a status code of 0. */ - if (fork_info->stacksize) - { - ((DWORD *)fork_info->stackbottom)[-17] = (DWORD)do_exit; - ((DWORD *)fork_info->stackbottom)[-15] = (DWORD)0; - } - - set_file_api_mode (current_codepage); - - MALLOC_CHECK; - - cygheap->fdtab.fixup_after_fork (hParent); - ProtectHandleINH (hParent); - - pinfo_fixup_after_fork (); - signal_fixup_after_fork (); - - MALLOC_CHECK; - - if (fixup_mmaps_after_fork (hParent)) - api_fatal ("recreate_mmaps_after_fork_failed"); - - /* 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) - sync_with_parent ("performed fork fixup.", FALSE); - else - { - dlls.load_after_fork (hParent, first_dll); - sync_with_parent ("loaded dlls", TRUE); - } - - ForceCloseHandle (hParent); - (void) ForceCloseHandle1 (fork_info->subproc_ready, subproc_ready); - (void) ForceCloseHandle1 (fork_info->forker_finished, forker_finished); - - if (fixup_shms_after_fork ()) - api_fatal ("recreate_shm areas after fork failed"); - - /* Set thread local stuff to zero. Under Windows 95/98 this is sometimes - non-zero, for some reason. - FIXME: There is a memory leak here after a fork. */ - for (per_thread **t = threadstuff; *t; t++) - if ((*t)->clear_on_fork ()) - (*t)->set (); - - wait_for_sigthread (); - pthread::atforkchild (); - cygbench ("fork-child"); - return 0; -} - -static void -slow_pid_reuse (HANDLE h) -{ - static NO_COPY HANDLE last_fork_procs[8] = {0}; - static NO_COPY unsigned nfork_procs = 0; - - if (nfork_procs >= (sizeof (last_fork_procs) / sizeof (last_fork_procs [0]))) - nfork_procs = 0; - /* Keep a list of handles to forked 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 (hMainProc, h, hMainProc, &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++; -} - -static int __stdcall -fork_parent (HANDLE& hParent, dll *&first_dll, - bool& load_dlls, void *stack_here, child_info_fork &ch) -{ - HANDLE subproc_ready, forker_finished; - DWORD rc; - PROCESS_INFORMATION pi = {0, NULL, 0, 0}; - - pthread::atforkprepare (); - - subproc_init (); - - int c_flags = GetPriorityClass (hMainProc) /*| - CREATE_NEW_PROCESS_GROUP*/; - STARTUPINFO si = {0, NULL, NULL, NULL, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, NULL, NULL, NULL, 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_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; - - /* Create an inheritable handle to pass to the child process. This will - allow the child to duplicate handles from the parent to itself. */ - hParent = NULL; - if (!DuplicateHandle (hMainProc, hMainProc, hMainProc, &hParent, 0, 1, - DUPLICATE_SAME_ACCESS)) - { - system_printf ("couldn't create handle to myself for child, %E"); - return -1; - } - - /* Remember the address of the first loaded dll and decide - if we need to load dlls. We do this here so that this - information will be available in the parent and, when - the stack is copied, in the child. */ - first_dll = dlls.start.next; - load_dlls = dlls.reload_on_fork && dlls.loaded_dlls; - - /* This will help some of the confusion. */ - fflush (stdout); - - subproc_ready = CreateEvent (&sec_all, FALSE, FALSE, NULL); - if (subproc_ready == NULL) - { - CloseHandle (hParent); - system_printf ("unable to allocate subproc_ready event, %E"); - return -1; - } - forker_finished = CreateEvent (&sec_all, FALSE, FALSE, NULL); - if (forker_finished == NULL) - { - CloseHandle (hParent); - CloseHandle (subproc_ready); - system_printf ("unable to allocate forker_finished event, %E"); - return -1; - } - - ProtectHandleINH (subproc_ready); - ProtectHandleINH (forker_finished); - - init_child_info (PROC_FORK, &ch, 1, subproc_ready); - - ch.forker_finished = forker_finished; - - stack_base (ch); - - si.cb = sizeof (STARTUPINFO); - si.lpReserved2 = (LPBYTE)&ch; - si.cbReserved2 = sizeof (ch); - - /* Remove impersonation */ - if (cygheap->user.issetuid ()) - RevertToSelf (); - - ch.parent = hParent; -#ifdef DEBUGGING - if (npid_max) - { - for (int pass = 0; pass < 2; pass++) - { - pid_t pid; - while ((pid = fork_pids[npid++])) - if (!pinfo (pid)) - { - ch.cygpid = pid; - goto out; - } - npid = 0; - } - } - out: -#endif - - char sa_buf[1024]; - PSECURITY_ATTRIBUTES sec_attribs = sec_user_nih (sa_buf); - syscall_printf ("CreateProcess (%s, %s, 0, 0, 1, %x, 0, 0, %p, %p)", - myself->progname, myself->progname, c_flags, &si, &pi); - __malloc_lock (); - void *newheap; - newheap = cygheap_setup_for_child (&ch,cygheap->fdtab.need_fixup_before ()); - rc = CreateProcess (myself->progname, /* image to run */ - myself->progname, /* what we send in arg0 */ - sec_attribs, - sec_attribs, - TRUE, /* inherit handles from parent */ - c_flags, - NULL, /* environment filled in later */ - 0, /* use current drive/directory */ - &si, - &pi); - - CloseHandle (hParent); - - if (!rc) - { - __seterrno (); - syscall_printf ("CreateProcessA failed, %E"); - ForceCloseHandle (subproc_ready); - ForceCloseHandle (forker_finished); - /* Restore impersonation */ - if (cygheap->user.issetuid ()) - ImpersonateLoggedOnUser (cygheap->user.token); - cygheap_setup_for_child_cleanup (newheap, &ch, 0); - return -1; - } - - /* Fixup the parent datastructure if needed and resume the child's - main thread. */ - if (!cygheap->fdtab.need_fixup_before ()) - cygheap_setup_for_child_cleanup (newheap, &ch, 0); - else - { - cygheap->fdtab.fixup_before_fork (pi.dwProcessId); - cygheap_setup_for_child_cleanup (newheap, &ch, 1); - ResumeThread (pi.hThread); - } - -#ifdef DEBUGGING - pinfo forked ((ch.cygpid != 1 ? ch.cygpid : cygwin_pid (pi.dwProcessId)), 1); -#else - pinfo forked (cygwin_pid (pi.dwProcessId), 1); -#endif - - /* Initialize things that are done later in dll_crt0_1 that aren't done - for the forkee. */ - strcpy (forked->progname, myself->progname); - - /* Restore impersonation */ - if (cygheap->user.issetuid ()) - ImpersonateLoggedOnUser (cygheap->user.token); - - ProtectHandle (pi.hThread); - /* Protect the handle but name it similarly to the way it will - be called in subproc handling. */ - ProtectHandle1 (pi.hProcess, childhProc); - - /* Fill in fields in the child's process table entry. */ - forked->hProcess = pi.hProcess; - forked->dwProcessId = pi.dwProcessId; - forked->copysigs (myself); - - /* 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 (!forked.remember ()) - { - TerminateProcess (pi.hProcess, 1); - set_errno (EAGAIN); - goto cleanup; - } - - slow_pid_reuse (pi.hProcess); - - /* Wait for subproc to initialize itself. */ - if (!sync_with_child (pi, subproc_ready, TRUE, "waiting for longjmp")) - goto cleanup; - - /* CHILD IS STOPPED */ - debug_printf ("child is alive (but stopped)"); - - /* Initialize, in order: data, bss, heap, stack, dll data, dll bss - Note: variables marked as NO_COPY will not be copied - since they are placed in a protected segment. */ - - - MALLOC_CHECK; - rc = fork_copy (pi, "user/cygwin data", - user_data->data_start, user_data->data_end, - user_data->bss_start, user_data->bss_end, - cygheap->heapbase, cygheap->heapptr, - stack_here, ch.stackbottom, - dll_data_start, dll_data_end, - dll_bss_start, dll_bss_end, NULL); - - __malloc_unlock (); - MALLOC_CHECK; - if (!rc) - 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 (!fork_copy (pi, "linked dll data/bss", d->p.data_start, d->p.data_end, - d->p.bss_start, d->p.bss_end, - NULL)) - goto cleanup; - } - - /* Start thread, and wait for it to reload dlls. */ - if (!resume_child (pi, forker_finished) || - !sync_with_child (pi, subproc_ready, load_dlls, "child loading dlls")) - 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 (!fork_copy (pi, "loaded dll data/bss", d->p.data_start, d->p.data_end, - d->p.bss_start, d->p.bss_end, - NULL)) - goto cleanup; - } - /* Start the child up again. */ - (void) resume_child (pi, forker_finished); - } - - ForceCloseHandle (subproc_ready); - ForceCloseHandle (pi.hThread); - ForceCloseHandle (forker_finished); - forker_finished = NULL; - pi.hThread = NULL; - pthread::atforkparent (); - - return forked->pid; - -/* Common cleanup code for failure cases */ - cleanup: - /* Remember to de-allocate the fd table. */ - if (pi.hProcess) - ForceCloseHandle1 (pi.hProcess, childhProc); - if (pi.hThread) - ForceCloseHandle (pi.hThread); - if (subproc_ready) - ForceCloseHandle (subproc_ready); - if (forker_finished) - ForceCloseHandle (forker_finished); - return -1; -} - -extern "C" int -fork () -{ - struct - { - HANDLE hParent; - dll *first_dll; - bool load_dlls; - } grouped; - - MALLOC_CHECK; - sigframe thisframe (mainthread); - - debug_printf ("entering"); - grouped.hParent = grouped.first_dll = NULL; - grouped.load_dlls = 0; - - if (ISSTATE(myself, PID_SPLIT_HEAP)) - { - system_printf ("The heap has been split, CYGWIN can't fork this process."); - system_printf ("Increase the heap_chunk_size in the registry and try again."); - set_errno (ENOMEM); - syscall_printf ("-1 = fork (), split heap"); - return -1; - } - - void *esp; - __asm__ volatile ("movl %%esp,%0": "=r" (esp)); - - myself->set_has_pgid_children (); - - child_info_fork ch; - - int res = setjmp (ch.jmp); - - if (res) - res = fork_child (grouped.hParent, grouped.first_dll, grouped.load_dlls); - else - res = fork_parent (grouped.hParent, grouped.first_dll, grouped.load_dlls, esp, ch); - - MALLOC_CHECK; - syscall_printf ("%d = fork()", res); - return res; -} -#ifdef DEBUGGING -void -fork_init () -{ - char buf[1024]; - if (!GetEnvironmentVariable ("CYGWIN_FORK_PIDS", buf, 1024)) - return; - pid_t pid; - char *p, *pe; - for (p = buf; (pid = strtol (p, &pe, 10)); p = pe) - fork_pids[npid_max++] = pid; -} -#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 - return fork (); -#else - sigframe thisframe; - vfork_save *vf = get_vfork_val (); - char **esp, **pp; - - if (vf == NULL) - vf = vfork_storage.create (); - else if (vf->pid) - return fork (); - - 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; - int res = cygheap->fdtab.vfork_child_dup () ? 0 : -1; - debug_printf ("%d = vfork()", res); - return res; - } - - vf = get_vfork_val (); - - for (pp = (char **)vf->frame, esp = vf->vfork_esp; - esp <= vf->vfork_ebp + 2; pp++, esp++) - *esp = *pp; - - thisframe.init (mainthread); - cygheap->fdtab.vfork_parent_restore (); - - myself->ctty = vf->ctty; - myself->sid = vf->sid; - myself->pgid = vf->pgid; - - 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 (); - return pid; -#endif -} |