| 1 | // %flair:license{
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| 2 | // This file is part of the Flair framework distributed under the
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| 3 | // CECILL-C License, Version 1.0.
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| 4 | // %flair:license}
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| 5 | // created: 2014/02/10
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| 6 | // filename: SharedMem_impl.cpp
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| 7 | //
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| 8 | // author: Guillaume Sanahuja
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| 9 | // Copyright Heudiasyc UMR UTC/CNRS 7253
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| 10 | //
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| 11 | // version: $Id: $
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| 12 | //
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| 13 | // purpose: Class defining a shared memory
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| 14 | //
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| 15 | //
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| 16 | /*********************************************************************/
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| 17 |
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| 18 | #include "SharedMem_impl.h"
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| 19 | #include "SharedMem.h"
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| 20 | #include <fcntl.h>
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| 21 | #include <unistd.h>
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| 22 | #include <sys/mman.h>
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| 23 | #include <string.h>
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| 24 |
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| 25 | using std::string;
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| 26 | using namespace flair::core;
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| 27 |
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| 28 | SharedMem_impl::SharedMem_impl(const SharedMem *self, string name, size_t size, SharedMem::Type &type):self(self),type(type),size(size),
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| 29 | sem(self,1,"/" + name + "_mutex"), sem_producer(self,0,"/" + name + "_producer"),sem_consumer(self,0,"/" + name + "_consumer") {
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| 30 |
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| 31 | char errorMsg[256];
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| 32 |
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| 33 | #ifdef __XENO__
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| 34 | heap_binded = false;
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| 35 | int status = rt_heap_create(&heap, name.c_str(), size,
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| 36 | H_SHARED | H_FIFO | H_NONCACHED);
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| 37 | if (status == -EEXIST) {
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| 38 | heap_binded = true;
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| 39 | status = rt_heap_bind(&heap, name.c_str(), TM_INFINITE);
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| 40 | }
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| 41 | if (status != 0) {
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| 42 | self->Err("rt_heap_create error (%s)\n", strerror_r(-status, errorMsg, sizeof(errorMsg)));
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| 43 | return;
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| 44 | }
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| 45 |
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| 46 | void *ptr;
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| 47 | status = rt_heap_alloc(&heap, 0, TM_NONBLOCK, &ptr);
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| 48 | if (status != 0) {
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| 49 | self->Err("rt_heap_alloc error (%s)\n", strerror_r(-status, errorMsg, sizeof(errorMsg)));
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| 50 | }
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| 51 | mem_segment = (char *)ptr;
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| 52 |
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| 53 | #else
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| 54 | shm_name = "/" + name;
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| 55 | fd = shm_open(shm_name.c_str(), O_RDWR | O_CREAT, 0666);
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| 56 | if (fd == -1) {
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| 57 | self->Err("Error creating shared memory\n");
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| 58 | }
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| 59 | ftruncate(fd, size);
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| 60 |
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| 61 | mem_segment = (char *)mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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| 62 | if (mem_segment == MAP_FAILED) {
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| 63 | self->Err("Failed to map memory\n");
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| 64 | }
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| 65 | #endif
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| 66 | }
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| 67 |
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| 68 | SharedMem_impl::~SharedMem_impl() {
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| 69 | int status;
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| 70 | char errorMsg[256];
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| 71 |
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| 72 | #ifdef __XENO__
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| 73 |
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| 74 | if (heap_binded == false) {
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| 75 | status = rt_heap_delete(&heap);
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| 76 | if (status != 0) {
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| 77 | self->Err("rt_heap_delete error (%s)\n", strerror_r(-status, errorMsg, sizeof(errorMsg)));
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| 78 | }
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| 79 | }
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| 80 |
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| 81 | #else
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| 82 | status = munmap(mem_segment, size);
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| 83 | if (status != 0) {
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| 84 | self->Err("Failed to unmap memory (%s)\n", strerror_r(-status, errorMsg, sizeof(errorMsg)));
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| 85 | }
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| 86 |
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| 87 | status = close(fd);
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| 88 | if (status != 0) {
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| 89 | self->Err("Failed to close file (%s)\n", strerror_r(-status, errorMsg, sizeof(errorMsg)));
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| 90 | }
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| 91 |
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| 92 | // do not check errors as it can be done by another process
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| 93 | status = shm_unlink(shm_name.c_str()); /*
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| 94 | if(status!=0)
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| 95 | {
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| 96 | self->Err("Failed to unlink memory (%s)\n",strerror_r(-status, errorMsg, sizeof(errorMsg)));
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| 97 | }
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| 98 | */
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| 99 | #endif
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| 100 | }
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| 101 |
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| 102 | void SharedMem_impl::ReaderReady() {
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| 103 | sem_consumer.ReleaseSemaphore();
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| 104 | }
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| 105 |
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| 106 | void SharedMem_impl::Write(const char *buf, size_t size) {
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| 107 | if (type==SharedMem::Type::mutex) {
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| 108 | sem.GetSemaphore();
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| 109 | memcpy(mem_segment, buf, size);
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| 110 | sem.ReleaseSemaphore();
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| 111 | } else if (type==SharedMem::Type::producerConsumer) {
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| 112 | //wait until consumer took the data away before writting a new one
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| 113 | //but should not block if nobody's there to read
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| 114 | if (sem_consumer.TryGetSemaphore()) {
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| 115 | memcpy(mem_segment, buf, size);
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| 116 | sem_producer.ReleaseSemaphore();
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| 117 | }
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| 118 | }
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| 119 | }
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| 120 |
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| 121 | bool SharedMem_impl::Read(char *buf, size_t size, Time nsTimeout) {
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| 122 | if (type==SharedMem::Type::mutex) {
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| 123 | if (sem.GetSemaphore()) {
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| 124 | memcpy(buf, mem_segment, size);
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| 125 | sem.ReleaseSemaphore();
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| 126 | return true;
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| 127 | }
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| 128 | } else if (type==SharedMem::Type::producerConsumer) {
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| 129 | if (sem_producer.GetSemaphore(nsTimeout)) {
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| 130 | memcpy(buf, mem_segment, size);
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| 131 | sem_consumer.ReleaseSemaphore();
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| 132 | return true;
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| 133 | }
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| 134 | }
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| 135 | return false;
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| 136 | }
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