xref: /xnu-11215/bsd/sys/pipe.h (revision e6231be0)
1 /*
2  * Copyright (c) 2004-2020 Apple Computer, Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 /*
29  * Copyright (c) 1996 John S. Dyson
30  * All rights reserved.
31  *
32  * Redistribution and use in source and binary forms, with or without
33  * modification, are permitted provided that the following conditions
34  * are met:
35  * 1. Redistributions of source code must retain the above copyright
36  *    notice immediately at the beginning of the file, without modification,
37  *    this list of conditions, and the following disclaimer.
38  * 2. Redistributions in binary form must reproduce the above copyright
39  *    notice, this list of conditions and the following disclaimer in the
40  *    documentation and/or other materials provided with the distribution.
41  * 3. Absolutely no warranty of function or purpose is made by the author
42  *    John S. Dyson.
43  * 4. This work was done expressly for inclusion into FreeBSD.  Other use
44  *    is allowed if this notation is included.
45  * 5. Modifications may be freely made to this file if the above conditions
46  *    are met.
47  *
48  * $FreeBSD: src/sys/sys/pipe.h,v 1.24 2003/08/13 20:01:38 alc Exp $
49  */
50 /*
51  * NOTICE: This file was modified by SPARTA, Inc. in 2006 to introduce
52  * support for mandatory and extensible security protections.  This notice
53  * is included in support of clause 2.2 (b) of the Apple Public License,
54  * Version 2.0.
55  */
56 
57 #ifndef _SYS_PIPE_H_
58 #define _SYS_PIPE_H_
59 
60 #ifdef  KERNEL
61 #include <libkern/locks.h>
62 #include <os/base.h>
63 #endif
64 #include <sys/queue.h>                  /* for TAILQ macros */
65 #include <sys/ev.h>
66 #include <sys/cdefs.h>
67 #include <sys/_types/_caddr_t.h>
68 #include <sys/_types/_u_int.h>
69 
70 /*
71  * Pipe buffer size, keep moderate in value, pipes take kva space.
72  */
73 #ifndef PIPE_SIZE
74 #define PIPE_SIZE       16384
75 #endif
76 
77 #define PIPE_KVAMAX     (1024 * 1024 * 16)
78 
79 #ifndef BIG_PIPE_SIZE
80 #define BIG_PIPE_SIZE   (64*1024)
81 #endif
82 
83 #ifndef SMALL_PIPE_SIZE
84 #define SMALL_PIPE_SIZE PAGE_SIZE
85 #endif
86 
87 /*
88  * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
89  * than PIPE_BUF.
90  */
91 #ifndef PIPE_MINDIRECT
92 #define PIPE_MINDIRECT  8192
93 #endif
94 
95 #define PIPENPAGES      (BIG_PIPE_SIZE / PAGE_SIZE + 1)
96 
97 /*
98  * Pipe buffer information.
99  * Separate in, out, cnt are used to simplify calculations.
100  * Buffered write is active when the buffer.cnt field is set.
101  */
102 struct pipebuf {
103 	u_int   cnt;            /* number of chars currently in buffer */
104 	u_int   in;             /* in pointer */
105 	u_int   out;            /* out pointer */
106 	u_int   size;           /* size of buffer */
107 #if KERNEL
108 	caddr_t OS_PTRAUTH_SIGNED_PTR("pipe.buffer") buffer; /* kva of buffer */
109 #else
110 	caddr_t buffer; /* kva of buffer */
111 #endif /* KERNEL */
112 };
113 
114 
115 #ifdef PIPE_DIRECT
116 /*
117  * Information to support direct transfers between processes for pipes.
118  */
119 struct pipemapping {
120 	vm_offset_t     kva;            /* kernel virtual address */
121 	vm_size_t       cnt;            /* number of chars in buffer */
122 	vm_size_t       pos;            /* current position of transfer */
123 	int             npages;         /* number of pages */
124 	vm_page_t       ms[PIPENPAGES]; /* pages in source process */
125 };
126 #endif
127 
128 /*
129  * Bits in pipe_state.
130  */
131 #define PIPE_ASYNC      0x004   /* Async? I/O. */
132 #define PIPE_WANTR      0x008   /* Reader wants some characters. */
133 #define PIPE_WANTW      0x010   /* Writer wants space to put characters. */
134 #define PIPE_WANT       0x020   /* Pipe is wanted to be run-down. */
135 // was  PIPE_SEL        0x040   /* Pipe has a select active. */
136 #define PIPE_EOF        0x080   /* Pipe is in EOF condition. */
137 #define PIPE_LOCKFL     0x100   /* Process has exclusive access to pointers/data. */
138 #define PIPE_LWANT      0x200   /* Process wants exclusive access to pointers/data. */
139 #define PIPE_DIRECTW    0x400   /* Pipe direct write active. */
140 #define PIPE_DIRECTOK   0x800   /* Direct mode ok. */
141 // was  PIPE_KNOTE      0x1000
142 #define PIPE_DRAIN      0x2000  /* Waiting for I/O to drop for a close.  Treated like EOF;
143 	                         *       only separate for easier debugging. */
144 #define PIPE_WSELECT    0x4000  /* Some thread has done an FWRITE select on the pipe */
145 #define PIPE_DEAD       0x8000  /* Pipe is dead and needs garbage collection */
146 
147 #ifdef  KERNEL
148 
149 struct label;
150 
151 /*
152  * Per-pipe data structure.
153  * Two of these are linked together to produce bi-directional pipes.
154  */
155 struct pipe {
156 	struct  pipebuf pipe_buffer;    /* data storage */
157 #ifdef PIPE_DIRECT
158 	struct  pipemapping pipe_map;   /* pipe mapping for direct I/O */
159 #endif
160 	struct  selinfo pipe_sel;       /* for compat with select */
161 	pid_t   pipe_pgid;              /* information for async I/O */
162 	struct  pipe *pipe_peer;        /* link with other direction */
163 	u_int   pipe_state;             /* pipe status info */
164 	int     pipe_busy;              /* busy flag, mostly to handle rundown sanely */
165 	lck_mtx_t *pipe_mtxp;           /* shared mutex between both pipes */
166 	struct  timespec st_atimespec;  /* time of last access */
167 	struct  timespec st_mtimespec;  /* time of last data modification */
168 	struct  timespec st_ctimespec;  /* time of last status change */
169 	struct  label *pipe_label;      /* pipe MAC label - shared */
170 };
171 
172 #define PIPE_MTX(pipe)          ((pipe)->pipe_mtxp)
173 
174 #define PIPE_LOCK(pipe)         lck_mtx_lock(PIPE_MTX(pipe))
175 #define PIPE_UNLOCK(pipe)       lck_mtx_unlock(PIPE_MTX(pipe))
176 #define PIPE_LOCK_ASSERT(pipe, type)  LCK_MTX_ASSERT(PIPE_MTX(pipe), (type))
177 
178 __BEGIN_DECLS
179 extern int pipe_stat(struct pipe *, void *, int);
180 #ifdef BSD_KERNEL_PRIVATE
181 extern uint64_t pipe_id(struct pipe *);
182 #endif
183 __END_DECLS
184 
185 #endif  /* KERNEL */
186 
187 #endif /* !_SYS_PIPE_H_ */
188