mirror of
git://sourceware.org/git/newlib-cygwin.git
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3fbfcd11fb
Newlib's posix_spawn has been taken from FreeBSD. The code relies on BSD-specific behaviour of vfork, namely the fact that vfork blocks the parent until the child exits or calls execve as well as the fact that the child shares parent memory in non-COW mode. This behaviour can't be emulated by Cygwin. Cygwin's vfork is equivalent to fork. This is POSIX-compliant, but it's lacking BSD's vfork ingrained synchronization of the parent to wait for the child calling execve, or the chance to just write a variable and the parent will see the result. So this requires a Cygwin-specific solution. The core function of posix_spawn, called do_posix_spawn is now implemented twice, once using the BSD method, and once for Cygwin using Windows synchronization under the hood waiting for the child to call execve and signalling errors upstream. The Windows specifics are hidden inside Cygwin, so newlib only calls internal Cygwin functions. Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
213 lines
5.2 KiB
C++
213 lines
5.2 KiB
C++
/* child_info.h: shared child info for cygwin
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This file is part of Cygwin.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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#include <setjmp.h>
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enum child_info_types
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{
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_CH_NADA = 0,
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_CH_EXEC = 1,
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_CH_SPAWN = 2,
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_CH_FORK = 3,
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_CH_WHOOPS = 4
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};
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enum child_status
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{
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_CI_STRACED = 0x01,
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_CI_ISCYGWIN = 0x02,
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_CI_SAW_CTRL_C = 0x04,
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_CI_SILENTFAIL = 0x08
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};
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#define OPROC_MAGIC_MASK 0xff00ff00
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#define OPROC_MAGIC_GENERIC 0xaf00f000
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#ifdef __x86_64__
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#define PROC_MAGIC_GENERIC 0xaf00fa64
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#else /*!x86_64*/
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#define PROC_MAGIC_GENERIC 0xaf00fa32
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#endif
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#define EXEC_MAGIC_SIZE sizeof(child_info)
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/* Change this value if you get a message indicating that it is out-of-sync. */
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#define CURR_CHILD_INFO_MAGIC 0xecc930b9U
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#define NPROCS 256
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#include "pinfo.h"
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struct cchildren
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{
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pid_t pid;
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pinfo_minimal p;
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};
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/* NOTE: Do not make gratuitous changes to the names or organization of the
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below class. The layout is checksummed to determine compatibility between
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different cygwin versions. */
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class child_info
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{
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public:
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DWORD msv_count; // set to pseudo-count on Vista WOW64, zeroed otherwise
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DWORD cb; // size of this record
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DWORD intro; // improbable string
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DWORD magic; // magic number unique to child_info
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unsigned short type; // type of record, exec, spawn, fork
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init_cygheap *cygheap;
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void *cygheap_max;
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unsigned char flag;
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int retry; // number of times we've tried to start child process
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HANDLE rd_proc_pipe;
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HANDLE wr_proc_pipe;
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HANDLE subproc_ready; // used for synchronization with parent
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HANDLE user_h;
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HANDLE parent;
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DWORD parent_winpid;
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DWORD cygheap_reserve_sz;
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unsigned fhandler_union_cb;
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DWORD exit_code; // process exit code
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static int retry_count;// retry count;
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child_info (unsigned, child_info_types, bool);
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child_info (): subproc_ready (NULL), parent (NULL) {}
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~child_info ();
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void refresh_cygheap () { cygheap_max = ::cygheap_max; }
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void ready (bool);
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bool __reg3 sync (int, HANDLE&, DWORD);
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DWORD __reg2 proc_retry (HANDLE);
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bool isstraced () const {return !!(flag & _CI_STRACED);}
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bool iscygwin () const {return !!(flag & _CI_ISCYGWIN);}
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bool saw_ctrl_c () const {return !!(flag & _CI_SAW_CTRL_C);}
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bool silentfail () const {return !!(flag & _CI_SILENTFAIL);}
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void prefork (bool = false);
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void cleanup ();
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void postfork (pinfo& child)
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{
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ForceCloseHandle (wr_proc_pipe);
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wr_proc_pipe = NULL;
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child.set_rd_proc_pipe (rd_proc_pipe);
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rd_proc_pipe = NULL;
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}
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void silentfail (bool f)
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{
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if (f)
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flag |= _CI_SILENTFAIL;
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else
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flag &= ~_CI_SILENTFAIL;
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}
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};
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class mount_info;
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class child_info_fork: public child_info
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{
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public:
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HANDLE forker_finished;// for synchronization with child
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jmp_buf jmp; // where child will jump to
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void *stackaddr; // DeallocationStack or user-provided allocation address
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// of parent thread
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void *stacklimit; // StackLimit of parent thread
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void *stackbase; // StackBase of parent thread
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size_t guardsize; // size of POSIX guard region or (size_t) -1 if
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// user stack
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char filler[4];
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child_info_fork ();
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void __reg1 handle_fork ();
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bool abort (const char *fmt = NULL, ...);
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void alloc_stack ();
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};
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class fhandler_base;
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class cygheap_exec_info
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{
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public:
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int argc;
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char **argv;
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int envc;
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char **envp;
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HANDLE myself_pinfo;
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sigset_t sigmask;
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int nchildren;
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cchildren children[0];
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static cygheap_exec_info *alloc ();
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void record_children ();
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void reattach_children (HANDLE);
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};
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class child_info_spawn: public child_info
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{
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HANDLE hExeced;
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HANDLE ev;
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HANDLE sem;
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pid_t cygpid;
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public:
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cygheap_exec_info *moreinfo;
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int __stdin;
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int __stdout;
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char filler[4];
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void cleanup ();
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child_info_spawn () {};
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child_info_spawn (child_info_types, bool);
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void record_children ();
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void reattach_children ();
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void *operator new (size_t, void *p) __attribute__ ((nothrow)) {return p;}
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void set (child_info_types ci, bool b) { new (this) child_info_spawn (ci, b);}
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void __reg1 handle_spawn ();
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void set_sem (HANDLE _sem)
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{
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/* Don't leak semaphore handle into exec'ed process. */
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SetHandleInformation (sem = _sem, HANDLE_FLAG_INHERIT, 0);
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}
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bool set_saw_ctrl_c ()
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{
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if (!has_execed ())
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return false;
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flag |= _CI_SAW_CTRL_C;
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return true;
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}
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bool signal_myself_exited ()
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{
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if (!ev)
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return false;
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else
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{
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SetEvent (ev);
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return true;
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}
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}
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void wait_for_myself ();
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bool has_execed () const
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{
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if (hExeced)
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return true;
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if (type != _CH_EXEC)
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return false;
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return !!hExeced;
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}
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bool get_parent_handle ();
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bool has_execed_cygwin () const { return iscygwin () && has_execed (); }
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operator HANDLE& () {return hExeced;}
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int __reg3 worker (const char *, const char *const *, const char *const [],
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int, int = -1, int = -1);
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};
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extern child_info_spawn ch_spawn;
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#define have_execed ch_spawn.has_execed ()
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#define have_execed_cygwin ch_spawn.has_execed_cygwin ()
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void __stdcall init_child_info (DWORD, child_info *, HANDLE);
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extern "C" {
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extern child_info *child_proc_info;
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extern child_info_spawn *spawn_info asm (_SYMSTR (child_proc_info));
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extern child_info_fork *fork_info asm (_SYMSTR (child_proc_info));
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}
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