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Reactos
1/***
2*wait.c - wait for child process to terminate
3*
4* Copyright (c) Microsoft Corporation. All rights reserved.
5*
6*Purpose:
7* defines _wait() - wait for child process to terminate
8*
9*******************************************************************************/
10
11#include <corecrt_internal.h>
12#include <errno.h>
13#include <process.h>
14#include <stdlib.h>
15
16/***
17*int _cwait(stat_loc, process_id, action_code) - wait for specific child
18* process
19*
20*Purpose:
21* The function _cwait() suspends the calling-process until the specified
22* child-process terminates. If the specifed child-process terminated
23* prior to the call to _cwait(), return is immediate.
24*
25*Entry:
26* int *stat_loc - pointer to where status is stored or nullptr
27* process_id - specific process id to be interrogated (0 means any)
28* action_code - specific action to perform on process ID
29* either _WAIT_CHILD or _WAIT_GRANDCHILD
30*
31*Exit:
32* process ID of terminated child or -1 on error
33*
34* *stat_loc is updated to contain the following:
35* Normal termination: lo-byte = 0, hi-byte = child exit code
36* Abnormal termination: lo-byte = term status, hi-byte = 0
37*
38*Exceptions:
39*
40*******************************************************************************/
41
42extern "C" intptr_t __cdecl _cwait(
43 int* const exit_code_result,
44 intptr_t const process_id,
45 int const action_code
46 )
47{
48 DBG_UNREFERENCED_PARAMETER(action_code);
49
50 if (exit_code_result)
51 *exit_code_result = static_cast<DWORD>(-1);
52
53 // Explicitly check for process ids -1 and -2. In Windows NT, -1 is a handle
54 // to the current process and -2 is a handle to the current thread, and the
55 // OS will let you wait (forever) on either.
56 _VALIDATE_RETURN_NOEXC(process_id != -1 && process_id != -2, ECHILD, -1);
57
58 __crt_unique_handle process_handle(reinterpret_cast<HANDLE>(process_id));
59
60 // Wait for the child process and get its exit code:
61 DWORD exit_code;
62 if (WaitForSingleObject(process_handle.get(), static_cast<DWORD>(-1)) == 0 &&
63 GetExitCodeProcess(process_handle.get(), &exit_code))
64 {
65 if (exit_code_result)
66 *exit_code_result = exit_code;
67
68 return process_id;
69 }
70
71 // One of the API calls failed; map the error and return failure.
72 DWORD const os_error = GetLastError();
73 if (os_error == ERROR_INVALID_HANDLE)
74 {
75 errno = ECHILD;
76 _doserrno = os_error;
77 }
78 else
79 {
80 __acrt_errno_map_os_error(os_error);
81 }
82
83 if (exit_code_result)
84 *exit_code_result = static_cast<DWORD>(-1);
85
86 return -1;
87}