{"id":3752,"date":"2020-07-08T10:03:36","date_gmt":"2020-07-08T01:03:36","guid":{"rendered":"https:\/\/now0930.pe.kr\/wordpress\/?p=3752"},"modified":"2020-07-08T20:00:28","modified_gmt":"2020-07-08T11:00:28","slug":"anonymous-memory-mapping-p308","status":"publish","type":"post","link":"https:\/\/now0930.pe.kr\/wordpress\/anonymous-memory-mapping-p308\/","title":{"rendered":"anonymous memory mapping, p308"},"content":{"rendered":"\n<figure class=\"wp-block-embed-wordpress wp-block-embed is-type-wp-embed is-provider-it-common-sense\"><div class=\"wp-block-embed__wrapper\">\nhttps:\/\/www.miroch.ru\/2017\/01\/17\/linux-process-memory-layout\/\n<\/div><figcaption>proc pid maps<\/figcaption><\/figure>\n\n\n\n<p>\uc5ec\uae30\ub97c \ucc38\uc870 \ud588\ub2e4.<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"c\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">#include &lt;stdio.h>\n#include &lt;sys\/mman.h>\n\nint main(int argc, char *argv[]) {\n\tchar *ptr;\n\tint ret;\n\n\tptr = (char *) mmap((void *) 0x10000, 512 * 1024, PROT_WRITE|PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);\n\tprintf(\"page size is %0x\\n\",getpagesize());\n\tprintf(\"ptr is %p\\n\",ptr);\n\n\tsleep(10);\n\t\/* all done with 'p', so give back the 512 KB mapping *\/\n\tret = munmap (ptr, 512 * 1024);\n\tif (ret)\n\t\tperror (\"munmap\");\n}\n<\/pre>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"shell\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">pi@raspberrypi:~\/Project\/cCode\/systemProgram $ .\/a.out &amp;\n[1] 3566\npi@raspberrypi:~\/Project\/cCode\/systemProgram $ page size is 1000\nptr is 0xb6ff0000\n\npi@raspberrypi:~\/Project\/cCode\/systemProgram $ cat \/proc\/3566\/maps\n00010000-00011000 r-xp 00000000 b3:02 386325     \/home\/pi\/Project\/cCode\/systemProgram\/a.out\n00020000-00021000 r--p 00000000 b3:02 386325     \/home\/pi\/Project\/cCode\/systemProgram\/a.out\n00021000-00022000 rw-p 00001000 b3:02 386325     \/home\/pi\/Project\/cCode\/systemProgram\/a.out\n014a8000-014c9000 rw-p 00000000 00:00 0          [heap]\nb6e54000-b6f8c000 r-xp 00000000 b3:02 2038       \/lib\/arm-linux-gnueabihf\/libc-2.28.so\nb6f8c000-b6f9c000 ---p 00138000 b3:02 2038       \/lib\/arm-linux-gnueabihf\/libc-2.28.so\nb6f9c000-b6f9e000 r--p 00138000 b3:02 2038       \/lib\/arm-linux-gnueabihf\/libc-2.28.so\nb6f9e000-b6f9f000 rw-p 0013a000 b3:02 2038       \/lib\/arm-linux-gnueabihf\/libc-2.28.so\nb6f9f000-b6fa2000 rw-p 00000000 00:00 0 \nb6fb1000-b6fb5000 r-xp 00000000 b3:02 12827      \/usr\/lib\/arm-linux-gnueabihf\/libarmmem-v7l.so\nb6fb5000-b6fc4000 ---p 00004000 b3:02 12827      \/usr\/lib\/arm-linux-gnueabihf\/libarmmem-v7l.so\nb6fc4000-b6fc5000 r--p 00003000 b3:02 12827      \/usr\/lib\/arm-linux-gnueabihf\/libarmmem-v7l.so\nb6fc5000-b6fc6000 rw-p 00004000 b3:02 12827      \/usr\/lib\/arm-linux-gnueabihf\/libarmmem-v7l.so\nb6fc6000-b6fe6000 r-xp 00000000 b3:02 1963       \/lib\/arm-linux-gnueabihf\/ld-2.28.so\nb6ff0000-b6ff6000 rw-p 00000000 00:00 0 \nb6ff6000-b6ff7000 r--p 00020000 b3:02 1963       \/lib\/arm-linux-gnueabihf\/ld-2.28.so\nb6ff7000-b6ff8000 rw-p 00021000 b3:02 1963       \/lib\/arm-linux-gnueabihf\/ld-2.28.so\nbec5d000-bec7e000 rw-p 00000000 00:00 0          [stack]\nbef82000-bef83000 r-xp 00000000 00:00 0          [sigpage]\nbef83000-bef84000 r--p 00000000 00:00 0          [vvar]\nbef84000-bef85000 r-xp 00000000 00:00 0          [vdso]\nffff0000-ffff1000 r-xp 00000000 00:00 0          [vectors]\n<\/pre>\n\n\n\n<p>0x10000\uc5d0 \uba54\ubaa8\ub9ac\ub97c \uc694\uccad\ud588\uc73c\ub098, \ubd88\uac00\ub2a5\ud558\uc5ec 0xb6ff0000\uc5d0 0x2000 byte\ub97c \uc5bb\uc5c8\ub2e4. 512 KB\ub85c \ub2e4\uc2dc \ub9f5\ud551\ud558\uc5ec cat\/proc\/PID\/maps\ub85c \ud655\uc778\ud588\ub2e4. <\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"400\" src=\"https:\/\/now0930.pe.kr\/wordpress\/wp-content\/uploads\/2020\/07\/anonymousmemorymap-1024x400.png\" alt=\"\" class=\"wp-image-3770\" srcset=\"https:\/\/now0930.pe.kr\/wordpress\/wp-content\/uploads\/2020\/07\/anonymousmemorymap-1024x400.png 1024w, https:\/\/now0930.pe.kr\/wordpress\/wp-content\/uploads\/2020\/07\/anonymousmemorymap-300x117.png 300w, https:\/\/now0930.pe.kr\/wordpress\/wp-content\/uploads\/2020\/07\/anonymousmemorymap-768x300.png 768w, https:\/\/now0930.pe.kr\/wordpress\/wp-content\/uploads\/2020\/07\/anonymousmemorymap.png 1201w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption>\uba54\ubaa8\ub9ac \uc601\uc5ed \ud06c\uae30, \uc8fc\uc18c \ube44\uad50.<\/figcaption><\/figure>\n\n\n\n<ul class=\"wp-block-list\"><li>heap \uc601\uc5ed \ubc16 \ub178\ub780\uc5f4\uc5d0 512KB\ub97c  \ud560\ub2f9 \ubc1b\uc558\ub2e4.(anonymous memory mapping)<\/li><li>a.out\uc774 3KB(1K+1K+1K)\uba54\ubaa8\ub9ac\ub97c \uc0ac\uc6a9\ud55c\ub2e4. 10,000~11,000\uae4c\uc9c0 \ud55c \ube14\ub7ed, 20,000 ~ 21,000\uae4c\uc9c0 \ud55c \ube14\ub85d. \ub098\uba38\uc9c0 21,000 ~ 22,000\ub294 offset 1K\ub97c \uc8fc\uace0 \uc0ac\uc6a9\ud55c\ub2e4.<\/li><li>a.out \ud30c\uc77c \ud06c\uae30\ub294 8KB \uc774\ub2e4. \ub098\uba38\uc9c0\ub294 \uba54\ubaa8\ub9ac\uc758 \ub2e4\ub978 \uc601\uc5ed\uc5d0 \ub123\ub294 \ub4ef \ud558\ub2e4.<\/li><li>libc-2.28.so\ub294 817KB \uba54\ubaa8\ub9ac\ub97c \uc0ac\uc6a9\ud55c\ub2e4.(0x138+0x10+0x2+0x1).<\/li><li>b5dbd000 ~ d6ef5000\uc5d0\uc11c 0x138KB\ub97c \uc0ac\uc6a9\ud558\uace0, \uadf8 \ub2e4\uc74c \uc8fc\uc18c\uc5d0 libc-2.28.so \ud30c\uc77c offset 0x138KB\ub9cc\ud07c \uc8fc\uace0 \uc0ac\uc6a9\ud55c\ub2e4. \uadf8 \ub4a4\ub85c \uac19\uc740 \ubc29\uc2dd\uc73c\ub85c \uc0ac\uc6a9\ud55c\ub2e4.<\/li><li>\ubcc4\ub3c4 \uc124\uc815\uc744 \ud558\uc9c0 \uc54a\uc744 \uacbd\uc6b0, heap\uacfc stack\uc740 \uac19\uc740 \ud06c\uae30\ub97c \uac16\ub294\ub2e4??<\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\uc5ec\uae30\ub97c \ucc38\uc870 \ud588\ub2e4. 0x10000\uc5d0 \uba54\ubaa8\ub9ac\ub97c \uc694\uccad\ud588\uc73c\ub098, \ubd88\uac00\ub2a5\ud558\uc5ec 0xb6ff0000\uc5d0 0x2000 byte\ub97c \uc5bb\uc5c8\ub2e4. 512 KB\ub85c \ub2e4\uc2dc \ub9f5\ud551\ud558\uc5ec cat\/proc\/PID\/maps\ub85c \ud655\uc778\ud588\ub2e4. heap \uc601\uc5ed \ubc16 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center 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