mirror of https://github.com/mkerrisk/man-pages
semctl.2: Add information on permission bits (based on sysvipc(7) text)
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
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@ -142,6 +142,25 @@ struct ipc_perm {
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.EE
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.EE
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.in
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.in
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.PP
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.PP
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The least significant 9 bits of the
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.I mode
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field of the
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.I ipc_perm
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structure define the access permissions for the shared memory segment.
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The permission bits are as follows:
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.TS
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l l.
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0400 Read by user
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0200 Write by user
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0040 Read by group
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0020 Write by group
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0004 Read by others
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0002 Write by others
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.TE
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.PP
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In effect, "write" means "alter" for a semaphore set.
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Bits 0100, 0010, and 0001 (the execute bits) are unused by the system.
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.PP
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Valid values for
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Valid values for
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.I cmd
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.I cmd
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are:
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are:
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