[669] | 1 | /* |
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| 2 | * pipe.h - single writer, single reader pipe specification. |
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| 3 | * |
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| 4 | * Author Alain Greiner (2016,2017,2018,2019,2020) |
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| 5 | * |
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| 6 | * Copyright (c) UPMC Sorbonne Universites |
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| 7 | * |
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| 8 | * This file is part of ALMOS-MKH. |
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| 9 | * |
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| 10 | * ALMOS-MKH is free software; you can redistribute it and/or modify it |
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| 11 | * under the terms of the GNU General Public License as published by |
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| 12 | * the Free Software Foundation; version 2.0 of the License. |
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| 13 | * |
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| 14 | * ALMOS-MKH is distributed in the hope that it will be useful, but |
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| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 17 | * General Public License for more details. |
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| 18 | * |
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| 19 | * You should have received a copy of the GNU General Public License |
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| 20 | * along with ALMOS-MKH; if not, write to the Free Software Foundation, |
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| 21 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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| 22 | */ |
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| 23 | |
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| 24 | |
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| 25 | #ifndef _PIPE_H_ |
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| 26 | #define _PIPE_H_ |
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| 27 | |
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| 28 | #include <hal_kernel_types.h> |
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| 29 | |
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| 30 | /******************************************************************************************* |
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| 31 | * This structure defines a generic, single writer, single reader, inter-processes |
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| 32 | * communication channel, used to implement both the POSIX named fifos, and the POSIX |
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| 33 | * anonymous pipes. |
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| 34 | * |
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| 35 | * It uses the (lower level) remote_buf_t object and access functions, and can be |
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| 36 | * allocated in any cluster, and accessed by threads running in any cluster. |
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| 37 | * The default buffer size is defined by the CONFIG_PIPE_BUF_SIZE parameter. |
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| 38 | * It it accessed by the user processes through the POSIX read/write syscalls, that call |
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| 39 | * the pipe_move_user() to move data between the kernel remote buf and the user buffer. |
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| 40 | * These access functions are blocking when the kernel buffer is full (for a write), |
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| 41 | * or empty (for a read), and use a desheduling policy, blocking on THREAD_ BLOCKED_IO. |
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| 42 | ******************************************************************************************/ |
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| 43 | |
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| 44 | typedef struct pipe_s |
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| 45 | { |
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| 46 | remote_buf_t * buffer; /*! local pointer on the remote_buf_t */ |
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| 47 | xptr_t writer_xp; /*! extended pointer on the writer thread */ |
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| 48 | xptr_t reader_xp; /*! extended pointer on the reader thread */ |
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| 49 | } |
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| 50 | pipe_t; |
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| 51 | |
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| 52 | /******************************************************************************************* |
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| 53 | * This function allocates memory for the pipe descriptor, for the remote_buf descriptor, |
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| 54 | * and for the associated data buffer, in the cluster defined by the <cxy> argument. |
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| 55 | * The buffer size is defined by the <size> argument. |
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| 56 | * The "buffer" field is set in the pipe descriptor, but the "writer_xp" and "reader_xp" |
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| 57 | * fields are not set by this function. |
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| 58 | ******************************************************************************************* |
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| 59 | * @ cxy : target cluster identifier. |
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| 60 | * @ size : data buffer size (in bytes). |
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| 61 | * @ return a local pointer on pipe_t if success /:w NULL if error. |
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| 62 | ******************************************************************************************/ |
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| 63 | pipe_t * pipe_create( cxy_t cxy, |
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| 64 | uint32_t size ); |
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| 65 | |
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| 66 | /******************************************************************************************* |
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| 67 | * This function releases all memory allocated fo a pipe: pipe descriptor, |
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| 68 | * remote_buffer_t descriptor, and associated data buffer. |
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| 69 | ******************************************************************************************* |
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| 70 | * @ pipe_xp : extended pointer on target pipe. |
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| 71 | ******************************************************************************************/ |
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| 72 | void pipe_destroy( xptr_t pipe_xp ); |
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| 73 | |
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| 74 | /******************************************************************************************* |
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| 75 | * These two functions update the "writer_xp" or "reader_xp" field in the pipe descriptor. |
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| 76 | * They are called when the user process open a file descriptor to access the pipe. |
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| 77 | ******************************************************************************************* |
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| 78 | * @ pipe_xp : extended pointer on the target thread |
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| 79 | * @ thread_xp : extended pointer on the client (writer/reader) thread. |
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| 80 | ******************************************************************************************/ |
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| 81 | void pipe_register_writer( xptr_t pipe_xp, |
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| 82 | xptr_t thread_xp ); |
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| 83 | |
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| 84 | void pipe_register_reader( xptr_t pipe_xp, |
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| 85 | xptr_t thread_xp ); |
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| 86 | |
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| 87 | /******************************************************************************************* |
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| 88 | * This blocking function is called by the sys_read() and sys_write() functions. |
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| 89 | * It moves up to <size> bytes between an user buffer, defined by the <u_buf> argument, |
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| 90 | * and the kernel pipe, identified by the <file_xp> argument. |
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| 91 | * The file descriptor is always located in the same cluster as the pipe descriptor. |
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| 92 | * The read/write direction is defined by the <to_buffer> argument. |
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| 93 | * It returns the number of bytes actually moved. |
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| 94 | * It uses a desheduling policy, blocking on THREAD_ BLOCKED_IO. |
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| 95 | ******************************************************************************************* |
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| 96 | * @ to_buffer : pipe -> buffer if true / buffer -> pipe if false. |
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| 97 | * @ file_xp : extended pointer on the remote file descriptor. |
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| 98 | * @ u_buf : user space buffer (virtual address). |
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| 99 | * @ size : requested number of bytes to move. |
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| 100 | * @ return number of bytes actually moved if success / -1 if error. |
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| 101 | ******************************************************************************************/ |
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| 102 | int pipe_user_move( bool_t to_buffer, |
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| 103 | xptr_t file_xp, |
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| 104 | void * u_buf, |
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| 105 | uint32_t size ); |
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| 106 | |
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| 107 | |
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| 108 | #endif /* _PIPE_H_ */ |
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