diff options
Diffstat (limited to 'winsup/cygwin/fork.cc')
| -rw-r--r-- | winsup/cygwin/fork.cc | 684 |
1 files changed, 0 insertions, 684 deletions
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc deleted file mode 100644 index f93d3a8..0000000 --- a/winsup/cygwin/fork.cc +++ /dev/null @@ -1,684 +0,0 @@ -/* fork.cc - - Copyright 1996, 1997, 1998, 1999, 2000 Cygnus Solutions. - -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 <fcntl.h> -#include <stdarg.h> -#include <errno.h> -#include "dll_init.h" -#include "fhandler.h" -#include "dtable.h" -#include "cygerrno.h" -#include "sync.h" -#include "sigproc.h" -#include "pinfo.h" -#include "perthread.h" - -DWORD NO_COPY chunksize = 0; -/* 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 = 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, %E", - what, pass, low, high, done); - 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", s); - 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"); - if (hang_child) - { - int n = SuspendThread (pi.hThread); - debug_printf ("suspend count %d", n); \ - } - return 1; -} - -static int -resume_child (PROCESS_INFORMATION &pi, HANDLE forker_finished) -{ - int rc; - - debug_printf ("here"); - SetEvent (forker_finished); - - rc = ResumeThread (pi.hThread); - - debug_printf ("rc %d", rc); - if (rc == 1) - return 1; // Successful resumption - - /* Can't resume the thread. Not sure why this would happen unless - there's a bug in the system. Things seem to be working OK now - though, so flag this with EAGAIN, but print a message on the - console. */ - small_printf ("fork: ResumeThread failed, rc = %d, %E\n", rc); - set_errno (EAGAIN); - syscall_printf ("-1 = fork(), ResumeThread failed"); - TerminateProcess (pi.hProcess, 1); - return 0; -} - -/* 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. */ -#define sync_with_parent(s, hang_self) \ -((void) ({ \ - debug_printf ("signalling parent: %s", s); \ - /* Tell our parent we're waiting. */ \ - if (!SetEvent (child_proc_info->subproc_ready)) \ - api_fatal ("fork child - SetEvent failed, %E"); \ - if (hang_self) \ - { \ - /* 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 (child_proc_info->forker_finished, FORK_WAIT_TIMEOUT); \ - switch (psync_rc) \ - { \ - case WAIT_TIMEOUT: \ - api_fatal ("sync_with_parent - WFSO timed out"); \ - break; \ - case WAIT_FAILED: \ - if (GetLastError () == ERROR_INVALID_HANDLE && \ - WaitForSingleObject (child_proc_info->forker_finished, 1) != WAIT_FAILED) \ - break; \ - api_fatal ("sync_with_parent - WFSO failed, fork_finished %p, %E", child_proc_info->forker_finished); \ - break; \ - default: \ - break; \ - } \ - debug_printf ("awake"); \ - } \ - 0; \ -})) - -static volatile void grow_stack_slack(); - -static void * -stack_dummy (int here) -{ - return &here; -} - -extern "C" int -fork () -{ - int res; - DWORD rc; - HANDLE hParent; - HANDLE subproc_ready, forker_finished; - void *stack_here; - int x; - PROCESS_INFORMATION pi = {0, NULL, 0, 0}; - static NO_COPY HANDLE last_fork_proc = NULL; - - MALLOC_CHECK; - - /* FIXME: something is broken when copying the stack from the parent - to the child; we try various tricks here to make sure that the - stack is good enough to prevent page faults, but the true cause - is still unknown. DJ */ - volatile char dummy[4096]; - dummy[0] = dummy[4095] = 0; // Just to leave some slack in the stack - - grow_stack_slack (); - - debug_printf ("entering"); - /* Calculate how much of stack to copy to child */ - stack_here = stack_dummy (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; - } - - /* 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. */ - dll *first_dll = dlls.start.next; - int load_dlls = dlls.reload_on_fork && dlls.loaded_dlls; - - static child_info_fork ch; - x = setjmp (ch.jmp); - - if (x == 0) - { - /* This will help some of the confusion. */ - fflush (stdout); - - subproc_ready = CreateEvent (&sec_all, FALSE, FALSE, NULL); - forker_finished = CreateEvent (&sec_all, FALSE, FALSE, NULL); - ProtectHandle (subproc_ready); - ProtectHandle (forker_finished); - - /* If we didn't obtain all the resources we need to fork, allow the program - to continue, but record the fact that fork won't work. */ - if (forker_finished == NULL || subproc_ready == NULL) - { - system_printf ("unable to allocate fork() resources."); - system_printf ("fork() disabled."); - return -1; - } - - subproc_init (); - - debug_printf ("about to call setjmp"); - /* Parent. */ -#ifdef DEBUGGING - /* The ProtectHandle call allocates memory so we need to make sure - that enough is set aside here so that the sbrk pointer does not - move when ProtectHandle is called after the child is started. - Otherwise the sbrk pointers in the parent will not agree with - the child and when user_data is (regrettably) copied over, - the user_data->ptr field will not be accurate. */ - free (malloc (4096)); -#endif - - init_child_info (PROC_FORK1, &ch, 1, subproc_ready); - - ch.forker_finished = forker_finished; - ch.heaptop = user_data->heaptop; - ch.heapbase = user_data->heapbase; - ch.heapptr = user_data->heapptr; - - stack_base (ch); - - STARTUPINFO si = {0, NULL, NULL, NULL, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, NULL, NULL, NULL, NULL}; - - si.cb = sizeof (STARTUPINFO); - si.lpReserved2 = (LPBYTE)&ch; - si.cbReserved2 = sizeof(ch); - - int c_flags = GetPriorityClass (hMainProc) /*| - CREATE_NEW_PROCESS_GROUP*/; - - /* If we don't have a console, then don't create a console for the - child either. */ - HANDLE console_handle = CreateFileA ("CONOUT$", GENERIC_WRITE, - FILE_SHARE_WRITE, &sec_none_nih, - OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, - NULL); - - syscall_printf ("CreateProcessA (%s, %s,0,0,1,%x, 0,0,%p,%p)", - myself->progname, myself->progname, c_flags, &si, &pi); - if (console_handle != INVALID_HANDLE_VALUE && console_handle != 0) - CloseHandle (console_handle); - else - c_flags |= DETACHED_PROCESS; - - hParent = NULL; - if (!DuplicateHandle (hMainProc, hMainProc, hMainProc, &hParent, 0, 1, - DUPLICATE_SAME_ACCESS)) - { - system_printf ("couldn't create handle to myself for child, %E"); - goto cleanup; - } - - /* Remove impersonation */ - uid_t uid = geteuid(); - if (myself->impersonated && myself->token != INVALID_HANDLE_VALUE) - seteuid (myself->orig_uid); - - char sa_buf[1024]; - rc = CreateProcessA (myself->progname, /* image to run */ - myself->progname, /* what we send in arg0 */ - allow_ntsec ? sec_user (sa_buf) : &sec_none_nih, - allow_ntsec ? sec_user (sa_buf) : &sec_none_nih, - 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 ("-1 = fork(), CreateProcessA failed"); - ForceCloseHandle(subproc_ready); - ForceCloseHandle(forker_finished); - subproc_ready = forker_finished = NULL; - /* Restore impersonation */ - if (myself->impersonated && myself->token != INVALID_HANDLE_VALUE) - seteuid (uid); - return -1; - } - - pinfo forked (cygwin_pid (pi.dwProcessId), 1); - - /* 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 (myself->impersonated && myself->token != INVALID_HANDLE_VALUE) - seteuid (uid); - - ProtectHandle (pi.hThread); - /* Protect the handle but name it similarly to the way it will - be called in subproc handling. */ - ProtectHandle1 (pi.hProcess, childhProc); - if (os_being_run != winNT) - { - if (last_fork_proc) - CloseHandle (last_fork_proc); - if (!DuplicateHandle (hMainProc, pi.hProcess, hMainProc, &last_fork_proc, - 0, FALSE, DUPLICATE_SAME_ACCESS)) - system_printf ("couldn't create last_fork_proc, %E"); - } - - /* Fill in fields in the child's process table entry. */ - forked->ppid = myself->pid; - forked->hProcess = pi.hProcess; - forked->dwProcessId = pi.dwProcessId; - forked->uid = myself->uid; - forked->gid = myself->gid; - forked->pgid = myself->pgid; - forked->sid = myself->sid; - forked->ctty = myself->ctty; - forked->umask = myself->umask; - forked->copysigs(myself); - forked->process_state |= PID_INITIALIZING | - (myself->process_state & PID_USETTY); - memcpy (forked->username, myself->username, MAX_USER_NAME); - if (myself->use_psid) - { - memcpy (forked->psid, myself->psid, MAX_SID_LEN); - forked->use_psid = 1; - } - memcpy (forked->logsrv, myself->logsrv, MAX_HOST_NAME); - memcpy (forked->domain, myself->domain, MAX_COMPUTERNAME_LENGTH+1); - forked->token = myself->token; - forked->impersonated = myself->impersonated; - forked->orig_uid = myself->orig_uid; - forked->orig_gid = myself->orig_gid; - forked->real_uid = myself->real_uid; - forked->real_gid = myself->real_gid; - strcpy (forked->root, myself->root); - forked->rootlen = myself->rootlen; - set_child_mmap_ptr (forked); - - /* 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, - ch.heapbase, ch.heapptr, - stack_here, ch.stackbottom, - dll_data_start, dll_data_end, - dll_bss_start, dll_bss_end, NULL); - - 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; - } - - forked.remember (); - - /* 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; - - res = forked->pid; - } - else - { - /**** Child *****/ - - /* We arrive here via a longjmp from "crt0". */ - (void) stack_dummy (0); // Just to make sure - debug_printf ("child is running %d", x); - - debug_printf ("pid %d, ppid %d", x, myself->ppid); - - /* Restore the inheritance state as in parent - Don't call setuid here! The flags are already set. */ - if (myself->impersonated) - { - debug_printf ("Impersonation of child, token: %d", myself->token); - if (myself->token == INVALID_HANDLE_VALUE) - RevertToSelf (); // probably not needed - else if (!ImpersonateLoggedOnUser (myself->token)) - system_printf ("Impersonate for forked child failed: %E"); - } - - sync_with_parent ("after longjmp.", TRUE); - ProtectHandle (hParent); - -#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 (child_proc_info->stacksize) - { - ((DWORD *)child_proc_info->stackbottom)[-17] = (DWORD)do_exit; - ((DWORD *)child_proc_info->stackbottom)[-15] = (DWORD)0; - } - - MALLOC_CHECK; - - fdtab.fixup_after_fork (hParent); - signal_fixup_after_fork (); - exec_fixup_after_fork (); - - 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) - sync_with_parent ("performed fork fixup.", FALSE); - else - { - dlls.load_after_fork (hParent, first_dll); - sync_with_parent ("loaded dlls", TRUE); - } - - ForceCloseHandle (hParent); - (void) ForceCloseHandle (child_proc_info->subproc_ready); - (void) ForceCloseHandle (child_proc_info->forker_finished); - - if (recreate_mmaps_after_fork (myself->mmap_ptr)) - api_fatal ("recreate_mmaps_after_fork_failed"); - - res = 0; - /* 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 (); - - /* Initialize signal/process handling */ - sigproc_init (); - } - - - MALLOC_CHECK; - syscall_printf ("%d = fork()", res); - return res; - -/* 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); - forker_finished = subproc_ready = NULL; - return -1; -} - -static volatile void -grow_stack_slack () -{ - volatile char dummy[16384]; - dummy[0] = dummy[16383] = 0; // Just to make some slack in the stack -} - -#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 - vfork_save *vf = get_vfork_val (); - char **esp, **pp; - - if (vf == NULL) - vf = vfork_storage.create (); - - 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 + 1; pp++, esp++) - *pp = *esp; - return fdtab.vfork_child_dup () ? 0 : -1; - } - - fdtab.vfork_parent_restore (); - - vf = get_vfork_val (); - if (vf->pid < 0) - { - int exitval = -vf->pid; - if ((vf->pid = fork ()) == 0) - exit (exitval); - } - - __asm__ volatile ("movl %%esp,%0": "=r" (esp):); - for (pp = (char **)vf->frame, esp = vf->vfork_esp; - esp <= vf->vfork_ebp + 1; pp++, esp++) - *esp = *pp; - - return vf->pid; -#endif -} |