{"id":1848,"date":"2023-08-26T16:36:25","date_gmt":"2023-08-26T16:36:25","guid":{"rendered":"http:\/\/example.com\/?p=851"},"modified":"2023-08-26T16:36:25","modified_gmt":"2023-08-26T16:36:25","slug":"851-mmap-and-munmap","status":"publish","type":"post","link":"https:\/\/w1.geleleger.nl\/rtgsk-851-mmap-and-munmap-unbrs\/","title":{"rendered":"Mmap And Munmap"},"content":{"rendered":"<div class=\"a1420ecab7e2234e1f4e9be5cee323bb\" data-index=\"1\" style=\"float: none; margin:10px 0 10px 0; text-align:center;\">\n<script type=\"text\/javascript\">\r\n\tatOptions = {\r\n\t\t'key' : '4a1f1119f949a4af74d56b8a3af8b867',\r\n\t\t'format' : 'iframe',\r\n\t\t'height' : 250,\r\n\t\t'width' : 300,\r\n\t\t'params' : {}\r\n\t};\r\n\tdocument.write('<scr' + 'ipt type=\"text\/javascript\" src=\"http' + (location.protocol === 'https:' ? 's' : '') + ':\/\/bleedingofficecontagion.com\/4a1f1119f949a4af74d56b8a3af8b867\/invoke.js\"><\/scr' + 'ipt>');\r\n<\/script>\n<\/div>\n\n<p><strong>Mmap And Munmap<\/strong>. <strong>mmap () creates a new mapping in the virtual address space of the calling process starting at addr and len bytes and munmap () removes any mappings for those entire pages containing any part of the address space of the process starting at addr and continuing for len bytes. If addr is not the address of a mapping established by a prior call to mmap (), the behavior is undefined. mmap, munmap &#8211; map or unmap files or devices into memory Synopsis #include &lt; sys\/mman.h &gt; void *mmap (void *addr, size_t lengthint &#34; prot &#34;, int &#34; flags , int fd, off_t offset);int munmap (void *addr, size_t length); See NOTES for information on feature test macro requirements. The mmap and munmap system calls allow UNIX programs to exert detailed control over their address spaces. The mmap () function shall be supported for the following memory objects: * Regular files * Shared memory objects * Typed memory objects Support for any other type of file is unspecified. Description The mmap () function shall establish a mapping between an address space of a process and a memory object. The starting address for the new mapping is specified in addr. They can be used to share memory among processes, to map files into process address spaces, and as part of user-level page fault schemes such as the garbage-collection algorithms discussed in lecture. Now since unlike free, munmap also takes length as parameter, therefore I put length as an additional information in the mapped memory.<\/strong><\/p>\n<p><figure> \t\t<img decoding=\"async\" src=\"https:\/\/image.3001.net\/images\/20181012\/1539330914_5bc0536255cfa.png\" alt=\"\u5806\u5165\u95e8\u7684\u5fc5\u5907\u57fa\u7840\u77e5\u8bc6-\u7f51\u76fe\u5b89\u5168\u57f9\u8bad\" style=\"width: 100%; padding: 5px; background-color: grey;\"><figcaption>\u5806\u5165\u95e8\u7684\u5fc5\u5907\u57fa\u7840\u77e5\u8bc6-\u7f51\u76fe\u5b89\u5168\u57f9\u8bad (Alvin Wood)<\/figcaption><\/figure>\n<p> \t \t<strong>Mmap And Munmap<\/strong>. <strong>For mmap(), offset must be a multiple of the underlying huge page size. The munmap() function may fail if: EINVAL The addr argument is not a multiple of the page size as returned by sysconf(). The mmap () function shall be supported for the following memory objects: * Regular files * Shared memory objects * Typed memory objects Support for any other type of file is unspecified. Stack Overflow About Products For Teams Using mmap () and munmap () Map or unmap files or devices into memory #include &lt;sys\/mman.h&gt; void *mmap (void *addr, size_t length, int prot, int flags, int fd, off_t offset); int munmap (void *addr, size_t length); How they work mmap () mmap () creates a new mapping in the virtual address space of the process calling it. The mmap and munmap system calls allow UNIX programs to exert detailed control over their address spaces.<\/strong> Mmap And Munmap. <\/p>\n<h3>The format of the call is as follows: pa = mmap.<\/h3>\n<p>Iowa is a state in the Midwest.<\/p>\n<div style=\"display: grid;grid-template-columns: auto auto auto; background: #eee; \">\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/raw.githubusercontent.com\/gaeduron\/Malloc\/master\/images\/malloc_find-space_flowchart_1.2.png\"><img decoding=\"async\" src=\"https:\/\/raw.githubusercontent.com\/gaeduron\/Malloc\/master\/images\/malloc_find-space_flowchart_1.2.png\" onerror=\"this.onerror=null;this.src='https:\/\/tse2.mm.bing.net\/th?id=OIP.vOAX7oV7UPLPcezOiwP1UwHaNd&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>GitHub &#8211; gaeduron\/Malloc: \ud83d\udcbe Memory Allocation &#8211; 42 project {Mmap &#8230;<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/dulishu.top\/wp-content\/uploads\/2016\/12\/KSO_@2P1UOXH2TCQ0.jpg\"><img decoding=\"async\" src=\"https:\/\/dulishu.top\/wp-content\/uploads\/2016\/12\/KSO_@2P1UOXH2TCQ0.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse2.mm.bing.net\/th?id=OIP.VIRDlGZObY77Mw0PAujHBgAAAA&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>\u8fdb\u7a0b\u95f4\u901a\u4fe1\u4e4b\u5171\u4eab\u5185\u5b58-mmap,munmap &#8211; \u53c8\u89c1\u675c\u68a8\u6811<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/pic4.zhimg.com\/v2-8aa0b1b8d3caf1d8b1429e7ed7288a7b_r.jpg\"><img decoding=\"async\" src=\"https:\/\/pic4.zhimg.com\/v2-8aa0b1b8d3caf1d8b1429e7ed7288a7b_r.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse1.mm.bing.net\/th?id=OIP.Kzn6Oi9f5s65NpwkcRV3JQHaD9&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>\u7cfb\u7edf\u8c03\u7528\u4e0e\u5185\u5b58\u7ba1\u7406\uff08sbrk\u3001brk\u3001mmap\u3001munmap\uff09 &#8211; \u77e5\u4e4e<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<div style=\"display: grid;grid-template-columns: auto auto auto; background: #eee; \">\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/images2015.cnblogs.com\/blog\/887009\/201601\/887009-20160128093947051-1977142700.png\"><img decoding=\"async\" src=\"https:\/\/images2015.cnblogs.com\/blog\/887009\/201601\/887009-20160128093947051-1977142700.png\" onerror=\"this.onerror=null;this.src='https:\/\/tse2.mm.bing.net\/th?id=OIP.S_jBqqMCJ-FpSkvg8Zo1UgEsB9&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>\u5171\u4eab\u5185\u5b58\u4e4b\u2014\u2014mmap\u5185\u5b58\u6620\u5c04 &#8211; touchcode &#8211; \u535a\u5ba2\u56ed<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/a.perfma.net\/img\/2191710\"><img decoding=\"async\" src=\"https:\/\/a.perfma.net\/img\/2191710\" onerror=\"this.onerror=null;this.src='https:\/\/tse3.mm.bing.net\/th?id=OIP.Ml_59sBp6bF5Jl_eyNxB_wHaEQ&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>\u4e16\u4e0a\u6700\u597d\u7684\u5171\u4eab\u5185\u5b58 | HeapDump\u6027\u80fd\u793e\u533a<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/pic1.zhimg.com\/v2-835bea3263aa717d1e3a36b1696f833c_r.jpg\"><img decoding=\"async\" src=\"https:\/\/pic1.zhimg.com\/v2-835bea3263aa717d1e3a36b1696f833c_r.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse4.mm.bing.net\/th?id=OIP.H5cFkaFbVauAYzg7JgDX6wHaFz&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>Linux mmap()\u7cfb\u7edf\u8c03\u7528 &#8211; \u77e5\u4e4e<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<div style=\"display: grid;grid-template-columns: auto auto auto; background: #eee; \">\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/pic4.zhimg.com\/v2-64b79368ff4eccb7c2d9119a5c38f143_b.jpg\"><img decoding=\"async\" src=\"https:\/\/pic4.zhimg.com\/v2-64b79368ff4eccb7c2d9119a5c38f143_b.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse4.mm.bing.net\/th?id=OIP.0JpqEd-a7Df69ONUpnzSvwHaCA&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>\u5206\u6790\u7531 mmap \u5bfc\u81f4\u7684\u5185\u5b58\u6cc4\u6f0f &#8211; \u77e5\u4e4e<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/pic3.zhimg.com\/v2-cc946dd1f4231673eb6536cdbd4fddae_b.jpg\"><img decoding=\"async\" src=\"https:\/\/pic3.zhimg.com\/v2-cc946dd1f4231673eb6536cdbd4fddae_b.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse4.mm.bing.net\/th?id=OIP.Y4mILiL-VjRxBKbUVzShYQHaHD&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>OSDI 2022 \u8bba\u6587\u8bc4\u8ff0-0x8\uff1aIsolation and OS Services &#8211; \u77e5\u4e4e<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/image.3001.net\/images\/20181012\/1539330914_5bc0536255cfa.png\"><img decoding=\"async\" src=\"https:\/\/image.3001.net\/images\/20181012\/1539330914_5bc0536255cfa.png\" onerror=\"this.onerror=null;this.src='https:\/\/tse3.mm.bing.net\/th?id=OIP.q_A4vikM-0_sxehk--P46wHaEh&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>\u5806\u5165\u95e8\u7684\u5fc5\u5907\u57fa\u7840\u77e5\u8bc6-\u7f51\u76fe\u5b89\u5168\u57f9\u8bad<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<div style=\"display: grid;grid-template-columns: auto auto auto; background: #eee; \">\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/image.slidesharecdn.com\/mmap-160426081701\/95\/linux-mmap-ioremap-introduction-17-638.jpg?cb=1461658652\"><img decoding=\"async\" src=\"https:\/\/image.slidesharecdn.com\/mmap-160426081701\/95\/linux-mmap-ioremap-introduction-17-638.jpg?cb=1461658652\" onerror=\"this.onerror=null;this.src='https:\/\/tse4.mm.bing.net\/th?id=OIP.rgyX2nZgKIYrdFtaTXzfbQHaFj&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>Linux MMAP &amp; Ioremap introduction<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/pic2.zhimg.com\/v2-2d87df055381b1c798095576fa12fff1_r.jpg\"><img decoding=\"async\" src=\"https:\/\/pic2.zhimg.com\/v2-2d87df055381b1c798095576fa12fff1_r.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse2.mm.bing.net\/th?id=OIP.qSOLRwlC0SD8bLElcJ0nzwHaEJ&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>\u5b8c\u5168\u5206\u6790Linux mmap\u539f\u7406\uff08\u770b\u5b8c\u609f\u4e86\uff09 &#8211; \u77e5\u4e4e<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/s2.loli.net\/2022\/11\/16\/U7xMgzj36dZDGaO.jpg\"><img decoding=\"async\" src=\"https:\/\/s2.loli.net\/2022\/11\/16\/U7xMgzj36dZDGaO.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse3.mm.bing.net\/th?id=OIP.m2n1l8b7d5UexxDDvYFNXQHaDI&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>\u8bfb\u6587\u7b14\u8bb0\uff1a\u5173\u4e8e MMAP \u4e0e SSD<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<p><strong>Mmap And Munmap<\/strong>. <strong>It is possible that an application has applied. This map shows cities, towns, counties, highways, main roads and secondary roads in Iowa. The mmap and munmap system calls allow UNIX programs to exert detailed control over their address spaces. The munmap() function may fail if: EINVAL The addr argument is not a multiple of the page size as returned by sysconf(). In colonial times, Iowa was a part of French Louisiana and Spanish Louisiana.<\/p>\n<p><\/strong> Mmap And Munmap.<\/p>\n<div class=\"a1420ecab7e2234e1f4e9be5cee323bb\" data-index=\"2\" style=\"float: none; margin:10px 0 10px 0; text-align:center;\">\n<script type=\"text\/javascript\">\r\n\tatOptions = {\r\n\t\t'key' : '4a1f1119f949a4af74d56b8a3af8b867',\r\n\t\t'format' : 'iframe',\r\n\t\t'height' : 250,\r\n\t\t'width' : 300,\r\n\t\t'params' : {}\r\n\t};\r\n\tdocument.write('<scr' + 'ipt type=\"text\/javascript\" src=\"http' + (location.protocol === 'https:' ? 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