| 1 | $Id: Fork.os2 1281 2004-03-06 21:48:26Z bird $
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| 2 |
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| 3 | Fork Design Draft
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| 4 | --------------------
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| 5 |
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| 6 | 1.0 Intro
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| 7 | ----------
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| 8 |
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| 9 | blah.
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| 10 |
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| 11 |
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| 12 | 1.1 The SuS fork() Description
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| 13 | ------------------------------
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| 14 |
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| 15 | NAME
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| 16 |
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| 17 | fork - create a new process
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| 18 |
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| 19 | SYNOPSIS
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| 20 |
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| 21 | #include <unistd.h>
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| 22 |
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| 23 | pid_t fork(void);
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| 24 |
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| 25 | DESCRIPTION
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| 26 |
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| 27 | The fork() function shall create a new process. The new process (child process) shall be an exact copy of the calling process (parent process) except as detailed below:
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| 28 |
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| 29 | * The child process shall have a unique process ID.
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| 30 | * The child process ID also shall not match any active process
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| 31 | group ID.
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| 32 | * The child process shall have a different parent process ID,
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| 33 | which shall be the process ID of the calling process.
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| 34 | * The child process shall have its own copy of the parent's file
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| 35 | descriptors. Each of the child's file descriptors shall refer
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| 36 | to the same open file description with the corresponding file
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| 37 | descriptor of the parent.
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| 38 | * The child process shall have its own copy of the parent's open
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| 39 | directory streams. Each open directory stream in the child process
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| 40 | may share directory stream positioning with the corresponding
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| 41 | directory stream of the parent.
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| 42 | * [XSI] The child process shall have its own copy of the parent's
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| 43 | message catalog descriptors.
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| 44 | * The child process' values of tms_utime, tms_stime, tms_cutime, and
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| 45 | tms_cstime shall be set to 0.
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| 46 | * The time left until an alarm clock signal shall be reset to zero,
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| 47 | and the alarm, if any, shall be canceled; see alarm() .
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| 48 | * [XSI] All semadj values shall be cleared.
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| 49 | * File locks set by the parent process shall not be inherited by
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| 50 | the child process.
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| 51 | * The set of signals pending for the child process shall be
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| 52 | initialized to the empty set.
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| 53 | * [XSI] Interval timers shall be reset in the child process.
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| 54 | * [SEM] Any semaphores that are open in the parent process shall
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| 55 | also be open in the child process.
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| 56 | * [ML] The child process shall not inherit any address space memory
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| 57 | locks established by the parent process via calls to mlockall()
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| 58 | or mlock().
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| 59 | * [MF|SHM] Memory mappings created in the parent shall be retained
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| 60 | in the child process. MAP_PRIVATE mappings inherited from the
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| 61 | parent shall also be MAP_PRIVATE mappings in the child, and any
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| 62 | modifications to the data in these mappings made by the parent
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| 63 | prior to calling fork() shall be visible to the child. Any
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| 64 | modifications to the data in MAP_PRIVATE mappings made by the
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| 65 | parent after fork() returns shall be visible only to the parent.
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