{"id":1877,"date":"2018-10-24T16:42:45","date_gmt":"2018-10-24T08:42:45","guid":{"rendered":"https:\/\/damogame.cn:15443\/wordpress\/?p=1877"},"modified":"2018-10-30T11:09:28","modified_gmt":"2018-10-30T03:09:28","slug":"mmap%e6%98%a0%e5%b0%84%e5%8c%ba%e5%92%8cshm%e5%85%b1%e4%ba%ab%e5%86%85%e5%ad%98%e7%9a%84%e5%8c%ba%e5%88%ab%e6%80%bb%e7%bb%93","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/1877","title":{"rendered":"mmap\u6620\u5c04\u533a\u548cshm\u5171\u4eab\u5185\u5b58\u7684\u533a\u522b\u603b\u7ed3"},"content":{"rendered":"
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linux<\/a>\u4e2d\u7684\u4e24\u79cd\u5171\u4eab\u5185\u5b58\u3002\u4e00\u79cd\u662f\u6211\u4eec\u7684IPC\u901a\u4fe1System V\u7248\u672c\u7684\u5171\u4eab\u5185\u5b58\uff0c\u53e6\u5916\u7684\u4e00\u79cd\u5c31\u662f\u6211\u4eec\u4eca\u5929\u63d0\u5230\u7684\u5b58\u50a8\u6620\u5c04I\/O\uff08mmap\u51fd\u6570\uff09<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
\n
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\u5728\u8bf4mmap\u4e4b\u524d\u6211\u4eec\u5148\u8bf4\u4e00\u4e0b\u666e\u901a\u7684\u8bfb\u5199\u6587\u4ef6\u7684\u539f\u7406\uff0c\u8fdb\u7a0b\u8c03\u7528read\u6216\u662fwrite\u540e\u4f1a\u9677\u5165\u5185\u6838\uff0c\u56e0\u4e3a\u8fd9\u4e24\u4e2a\u51fd\u6570\u90fd\u662f\u7cfb\u7edf\u8c03\u7528\uff0c\u8fdb\u5165\u7cfb\u7edf\u8c03\u7528\u540e\uff0c\u5185\u6838\u5f00\u59cb\u8bfb\u5199\u6587\u4ef6\uff0c\u5047\u8bbe\u5185\u6838\u5728\u8bfb\u53d6\u6587\u4ef6\uff0c\u5185\u6838\u9996\u5148\u628a\u6587\u4ef6\u8bfb\u5165\u81ea\u5df1\u7684\u5185\u6838\u7a7a\u95f4\uff0c\u8bfb\u5b8c\u4e4b\u540e\u8fdb\u7a0b\u5728\u5185\u6838\u56de\u5f52\u7528\u6237\u6001\uff0c\u5185\u6838\u628a\u8bfb\u5165\u5185\u6838\u5185\u5b58\u7684\u6570\u636e\u518dcopy\u8fdb\u5165\u8fdb\u7a0b\u7684\u7528\u6237\u6001\u5185\u5b58\u7a7a\u95f4\u3002\u5b9e\u9645\u4e0a\u6211\u4eec\u540c\u4e00\u4efd\u6587\u4ef6\u5185\u5bb9\u76f8\u5f53\u4e8e\u8bfb\u4e86\u4e24\u6b21\uff0c\u5148\u8bfb\u5165\u5185\u6838\u7a7a\u95f4\uff0c\u518d\u4ece\u5185\u6838\u7a7a\u95f4\u8bfb\u5165\u7528\u6237\u7a7a\u95f4\u3002<\/p>\n

Linux\u63d0\u4f9b\u4e86\u5185\u5b58\u6620\u5c04\u51fd\u6570mmap, \u5b83\u628a\u6587\u4ef6\u5185\u5bb9\u6620\u5c04\u5230\u4e00\u6bb5\u5185\u5b58\u4e0a(\u51c6\u786e\u8bf4\u662f\u865a\u62df\u5185\u5b58\u4e0a), \u901a\u8fc7\u5bf9\u8fd9\u6bb5\u5185\u5b58\u7684\u8bfb\u53d6\u548c\u4fee\u6539, \u5b9e\u73b0\u5bf9\u6587\u4ef6\u7684\u8bfb\u53d6\u548c\u4fee\u6539,mmap()\u7cfb\u7edf\u8c03\u7528\u4f7f\u5f97\u8fdb\u7a0b\u4e4b\u95f4\u53ef\u4ee5\u901a\u8fc7\u6620\u5c04\u4e00\u4e2a\u666e\u901a\u7684\u6587\u4ef6\u5b9e\u73b0\u5171\u4eab\u5185\u5b58\u3002\u666e\u901a\u6587\u4ef6\u6620\u5c04\u5230\u8fdb\u7a0b\u5730\u5740\u7a7a\u95f4\u540e\uff0c\u8fdb\u7a0b\u53ef\u4ee5\u5411\u8bbf\u95ee\u5185\u5b58\u7684\u65b9\u5f0f\u5bf9\u6587\u4ef6\u8fdb\u884c\u8bbf\u95ee\uff0c\u4e0d\u9700\u8981\u5176\u4ed6\u7cfb\u7edf\u8c03\u7528(read,write)\u53bb\u64cd\u4f5c\u3002<\/p>\n

mmap\u56fe\u793a\u4f8b\uff1a<\/p>\n

\"\"<\/p>\n

mmap\u7cfb\u7edf\u8c03\u7528\u4ecb\u7ecd<\/h2>\n
    \n
  1. \n
    <\/div>\n<\/li>\n<\/ol>\n
    void *mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset);<\/pre>\n
    \u8fd9\u5c31\u662fmmap\u7cfb\u7edf\u8c03\u7528\u7684\u63a5\u53e3\uff0cmmap\u51fd\u6570\u6210\u529f\u8fd4\u56de\u6307\u5411\u5185\u5b58\u533a\u57df\u7684\u6307\u9488\uff0c\u56fe\u4e0a\u7684\u8fdb\u7a0b\u7684\u5730\u5740\u7a7a\u95f4\u7684\u5f00\u59cb\u5730\u5740\u5c31\u662fmmap\u51fd\u6570\u7684\u8fd4\u56de\u503c\uff0c\u5931\u8d25\u8fd4\u56deMAP_FAILED\u3002<\/p>\n
    addr\uff0c\u67d0\u4e2a\u7279\u5b9a\u7684\u5730\u5740\u4f5c\u4e3a\u8d77\u59cb\u5730\u5740\uff0c\u5f53\u88ab\u8bbe\u7f6e\u4e3aNULL\uff0c\u7cfb\u7edf\u4f1a\u5728\u5730\u5740\u7a7a\u95f4\u9009\u62e9\u4e00\u5757\u5408\u9002\u7684\u5185\u5b58\u533a\u57df\u3002<\/p>\n
    length\u8bf4\u7684\u662f\u5185\u5b58\u6bb5\u7684\u957f\u5ea6\u3002<\/p>\n
    prot\u662f\u7528\u6765\u8bbe\u5b9a\u5185\u5b58\u6bb5\u7684\u8bbf\u95ee\u6743\u9650\u3002<\/p>\n\n\n\n\n\n\n\n\n
    prot\u53c2\u6570<\/th>\n\u8bf4\u660e<\/th>\n<\/tr>\n<\/thead>\n
    PROT_READ<\/td>\n\u5185\u5b58\u6bb5\u53ef\u8bfb<\/td>\n<\/tr>\n
    PROT_WRITE<\/td>\n\u5185\u5b58\u6bb5\u53ef\u5199<\/td>\n<\/tr>\n
    PROT_EXEC<\/td>\n\u5185\u5b58\u6bb5\u53ef\u6267\u884c<\/td>\n<\/tr>\n
    PROT_NONE<\/td>\n\u5185\u5b58\u6bb5\u4e0d\u80fd\u88ab\u8bbf\u95ee<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
    flags\u53c2\u6570\u63a7\u5236\u5185\u5b58\u6bb5\u5185\u5bb9\u88ab\u4fee\u6539\u4ee5\u540e\u7a0b\u5e8f\u7684\u884c\u4e3a\u3002<\/p>\n\n\n\n\n\n\n\n\n\n
    flags\u53c2\u6570<\/th>\n\u8bf4\u660e<\/th>\n<\/tr>\n<\/thead>\n
    MAP_SHARED<\/td>\n\u8fdb\u7a0b\u95f4\u5171\u4eab\u5185\u5b58\uff0c\u5bf9\u8be5\u5185\u5b58\u6bb5\u4fee\u6539\u53cd\u6620\u5230\u6620\u5c04\u6587\u4ef6\u4e2d\u3002\u63d0\u4f9b\u4e86POSIX\u5171\u4eab\u5185\u5b58<\/td>\n<\/tr>\n
    MAP_PRIVATE<\/td>\n\u5185\u5b58\u6bb5\u4e3a\u8c03\u7528\u8fdb\u7a0b\u6240\u79c1\u6709\u3002\u5bf9\u8be5\u5185\u5b58\u6bb5\u7684\u4fee\u6539\u4e0d\u4f1a\u53cd\u6620\u5230\u6620\u5c04\u6587\u4ef6<\/td>\n<\/tr>\n
    MAP_ANNOYMOUS<\/td>\n\u8fd9\u6bb5\u5185\u5b58\u4e0d\u662f\u4ece\u6587\u4ef6\u6620\u5c04\u800c\u6765\u7684\u3002\u5185\u5bb9\u88ab\u521d\u59cb\u5316\u4e3a\u51680<\/td>\n<\/tr>\n
    MAP_FIXED<\/td>\n\u5185\u5b58\u6bb5\u5fc5\u987b\u4f4d\u4e8estart\u53c2\u6570\u6307\u5b9a\u7684\u5730\u5740\u5904\uff0cstart\u5fc5\u987b\u662f\u9875\u5927\u5c0f\u7684\u6574\u6570\u500d\uff084K\u6574\u6570\u500d\uff09<\/td>\n<\/tr>\n
    MAP_HUGETLB<\/td>\n\u6309\u7167\u5927\u5185\u5b58\u9875\u9762\u6765\u5206\u914d\u5185\u5b58\u7a7a\u95f4<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
    fd\u53c2\u6570\u662f\u7528\u6765\u88ab\u6620\u5c04\u6587\u4ef6\u5bf9\u5e94\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u3002\u901a\u8fc7open\u7cfb\u7edf\u8c03\u7528\u5f97\u5230\u3002offset\u8bbe\u5b9a\u4ece\u4f55\u5904\u8fdb\u884c\u6620\u5c04\u3002<\/p>\n
    mmap\u4f7f\u7528\u6ce8\u610f\u4e8b\u9879\uff1a<\/p>\n
    \"\"<\/p>\n
    \u5229\u7528mmap\u8fdb\u884c\u975e\u8840\u7f18\u8fdb\u7a0b\u95f4\u901a\u4fe1\u4ee3\u7801\uff1a<\/p>\n
    #include<stdio.h>\r\n#include<stdlib.h>\r\n#include<unistd.h>\r\n#include<fcntl.h>\r\n#include<sys\/types.h>\r\n#include<sys\/stat.h>\r\n#include<sys\/mman.h>\r\n#include<string.h>\r\n \r\nstruct STU\r\n{\r\n  int age;\r\n  char name[20];\r\n  char sex;\r\n};\r\n \r\nint main(int argc,char *argv[]) \/\/\u8fd9\u4e2a\u8fdb\u7a0b\u7528\u4e8e\u521b\u5efa\u6620\u5c04\u533a\u8fdb\u884c\u5199\u3002\r\n{\r\n  if(argc != 2)\r\n  {\r\n    printf(\".\/a,out  file\");\r\n    exit(1);\r\n  }\r\n \r\n  struct STU student = {10,\"xiaoming\",'m'};\r\n \r\n  int fd = open(argv[1],O_RDWR|O_CREAT|O_TRUNC,0644);\r\n  if(fd < 0)\r\n  {\r\n    perror(\"open\");\r\n    exit(2);\r\n  }\r\n  ftruncate(fd,sizeof(struct STU)); \/\/\u6587\u4ef6\u62d3\u5c55\u5927\u5c0f\u3002\r\n  \r\n  struct STU *p = (struct STU*)mmap(NULL,sizeof(struct STU),PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);\/\/\u521b\u5efa\u4e00\u4e2a\u7ed3\u6784\u4f53\u5927\u5c0f\u7684\u5171\u4eab\u6620\u5c04\u533a\u3002\u5171\u4eab\u6620\u5c04\u533a\u6211\u4eec\u53ef\u4ee5\u5f53\u505a\u6570\u7ec4\u533a\u770b\u5f85\u3002\r\n  if(p == MAP_FAILED)\r\n  {\r\n    perror(\"mmap\");\r\n    exit(3);\r\n  }\r\n  close(fd); \/\/\u5173\u95ed\u4e0d\u7528\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\u3002\r\n  while(1)\r\n  {\r\n    memcpy(p,&student,sizeof(student));\r\n    student.age++;\r\n    sleep(1);\r\n  }\r\n  int ret = munmap(p,sizeof(student));\r\n  if(ret < 0)\r\n  {\r\n    perror(\"mmumap\");\r\n    exit(4);\r\n  }\r\n \r\n  return 0;\r\n}<\/pre>\n<\/div>\n<\/div>\n<\/article>\n
    #include<stdio.h>\r\n#include<stdlib.h>\r\n#include<unistd.h>\r\n#include<fcntl.h>\r\n#include<sys\/types.h>\r\n#include<sys\/stat.h>\r\n#include<sys\/mman.h>\r\n \r\nstruct STU\r\n{\r\n  int age;\r\n  char name[20];\r\n  char sex;\r\n};\r\n \r\nint main(int argc,char *argv[]) \/\/\u8fd9\u4e2a\u8fdb\u7a0b\u8bfb\r\n{\r\n  if(argc != 2)\r\n  {\r\n    printf(\".\/a,out  file\");\r\n    exit(1);\r\n  }\r\n \r\n \r\n  int fd = open(argv[1],O_RDONLY,0644);\r\n  if(fd < 0)\r\n  {\r\n    perror(\"open\");\r\n    exit(2);\r\n  }\r\n  \r\n  struct STU student;\r\n \r\n  struct STU *p = (struct STU*)mmap(NULL,sizeof(struct STU),PROT_READ,MAP_SHARED,fd,0);\r\n  if(p == MAP_FAILED)\r\n  {\r\n    perror(\"mmap\");\r\n    exit(3);\r\n  }\r\n  close(fd);\r\n  int i = 0;\r\n  while(1)\r\n  {\r\n    \r\n    printf(\"id = %d\\tname = %s\\t%c\\n\",p->age,p->name,p->sex);\t\r\n    sleep(2);\r\n  }\r\n  int ret = munmap(p,sizeof(student));\r\n  if(ret < 0)\r\n  {\r\n    perror(\"mmumap\");\r\n    exit(4);\r\n  }\r\n \r\n  return 0;\r\n}<\/pre>\n
    \n
    \n
    \n
    \u4ee3\u7801\u622a\u56fe\uff1a\"\"
    \n\"\"
    \n\u5206\u6790\uff1a\u56e0\u4e3a\u53ea\u521b\u5efa\u4e00\u4e2a\u7ed3\u6784\u4f53\u5927\u5c0f\u7684\u5171\u4eab\u5185\u5b58\uff0c\u540e\u9762\u5199\u5165\u7684\u6570\u636e\u628a\u524d\u9762\u5199\u5165\u7684\u6570\u636e\u8986\u76d6\u4e86\u3002<\/p>\n
    shm\u8c03\u7528\u4ecb\u7ecd:\u53c2\u89c1\u4e0a\u4e00\u7bc7\u535a\u5ba2<\/h2>\n
    http:\/\/blog.csdn.net\/hj605635529\/article\/details\/67636526<\/div>\n
    <\/div>\n
    shm\u56fe\u793a\u4f8b\uff1a<\/div>\n
    \"\"<\/div>\n
    <\/div>\n
    \uff081\uff09\u901a\u8fc7int shmget(key_t key, size_t size, int shmflg);\u5728\u7269\u7406\u5185\u5b58\u521b\u5efa\u4e00\u4e2a\u5171\u4eab\u5185\u5b58\uff0c\u8fd4\u56de\u5171\u4eab\u5185\u5b58\u7684\u7f16\u53f7\u3002
    \n\uff082\uff09\u901a\u8fc7void *shmat(int shmid, constvoid shmaddr,int shmflg);\u8fde\u63a5\u6210\u529f\u540e\u628a\u5171\u4eab\u5185\u5b58\u533a\u5bf9\u8c61\u6620\u5c04\u5230\u8c03\u7528\u8fdb\u7a0b\u7684\u5730\u5740\u7a7a\u95f4
    \n\uff083\uff09\u901a\u8fc7void *shmdt(constvoid* shmaddr);\u65ad\u5f00\u7528\u6237\u7ea7\u9875\u8868\u5230\u5171\u4eab\u5185\u5b58\u7684\u90a3\u6839\u7bad\u5934\u3002
    \n\uff084\uff09\u901a\u8fc7int shmctl(int shmid, int cmd, struct shmid_ds* buf);\u91ca\u653e\u7269\u7406\u5185\u5b58\u4e2d\u7684\u90a3\u5757\u5171\u4eab\u5185\u5b58\u3002<\/p>\n
    <\/div>\n
    \u603b\u7ed3mmap\u548cshm:
    \n1\u3001mmap\u662f\u5728\u78c1\u76d8\u4e0a\u5efa\u7acb\u4e00\u4e2a\u6587\u4ef6\uff0c\u6bcf\u4e2a\u8fdb\u7a0b\u5730\u5740\u7a7a\u95f4\u4e2d\u5f00\u8f9f\u51fa\u4e00\u5757\u7a7a\u95f4\u8fdb\u884c\u6620\u5c04\u3002
    \n\u800c\u5bf9\u4e8eshm\u800c\u8a00\uff0cshm\u6bcf\u4e2a\u8fdb\u7a0b\u6700\u7ec8\u4f1a\u6620\u5c04\u5230\u540c\u4e00\u5757\u7269\u7406\u5185\u5b58\u3002shm\u4fdd\u5b58\u5728\u7269\u7406\u5185\u5b58\uff0c\u8fd9\u6837\u8bfb\u5199\u7684\u901f\u5ea6\u8981\u6bd4\u78c1\u76d8\u8981\u5feb\uff0c\u4f46\u662f\u5b58\u50a8\u91cf\u4e0d\u662f\u7279\u522b\u5927\u3002
    \n2\u3001\u76f8\u5bf9\u4e8eshm\u6765\u8bf4\uff0cmmap\u66f4\u52a0\u7b80\u5355\uff0c\u8c03\u7528\u66f4\u52a0\u65b9\u4fbf\uff0c\u6240\u4ee5\u8fd9\u4e5f\u662f\u5927\u5bb6\u90fd\u559c\u6b22\u7528\u7684\u539f\u56e0\u3002
    \n3\u3001\u53e6\u5916mmap\u6709\u4e00\u4e2a\u597d\u5904\u662f\u5f53\u673a\u5668\u91cd\u542f\uff0c\u56e0\u4e3ammap\u628a\u6587\u4ef6\u4fdd\u5b58\u5728\u78c1\u76d8\u4e0a\uff0c\u8fd9\u4e2a\u6587\u4ef6\u8fd8\u4fdd\u5b58\u4e86\u64cd\u4f5c\u7cfb\u7edf\u540c\u6b65\u7684\u6620\u50cf\uff0c\u6240\u4ee5mmap\u4e0d\u4f1a\u4e22\u5931\uff0c\u4f46\u662fshmget\u5c31\u4f1a\u4e22\u5931\u3002<\/p>\n
    <\/div>\n<\/div>\n<\/div>\n<\/article>\n","protected":false},"excerpt":{"rendered":"
    linux\u4e2d\u7684\u4e24\u79cd\u5171\u4eab\u5185\u5b58\u3002\u4e00\u79cd\u662f\u6211\u4eec\u7684<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[],"tags":[119,101],"class_list":["post-1877","post","type-post","status-publish","format-standard","hentry","tag-03-","tag-101"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1877","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=1877"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1877\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=1877"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=1877"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=1877"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}