Linux Certif

Toute la documentation sur la certification Linux LPI

mremap

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mremap - ²¾ÁÛ¥á¥â¥ê¡¦¥¢¥É¥ì¥¹¤òºÆ¥Þ¥Ã¥Ô¥ó¥°¤¹¤ë

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#define _GNU_SOURCE




#include <sys/mman.h>



void *mremap(void *old_address, size_t old_size,

             size_t new_size, int flags);

ÀâÌÀ

mremap() ¤Ï´û¸¤Î¥á¥â¥ê¡¦¥Þ¥Ã¥Ô¥ó¥°¤Î³ÈÄ¥ (¤Þ¤¿¤Ï½Ì¾®) ¤ò¹Ô¤¦¡£ Ʊ»þ¤Ë°ÜÆ°¤µ¤ì¤ë¤³¤È¤â¤¢¤ë (flags °ú¤­¿ô¤ÈÍøÍѲÄǽ¤Ê²¾ÁÛ¥¢¥É¥ì¥¹¶õ´Ö¤Ë¤è¤Ã¤Æ·è¤Þ¤ë)¡£

old_address ¤Ï³ÈÄ¥ (¤Þ¤¿¤Ï½Ì¾®) ¤·¤è¤¦¤È¤¹¤ë²¾ÁÛ¥á¥â¥ê¡¦¥Ö¥í¥Ã¥¯ ¤Î¸µ¤Î¥¢¥É¥ì¥¹¤Ç¤¢¤ë¡£old_address ¤Ï¥Ú¡¼¥¸¶­³¦¤Ë¹ç¤Ã¤Æ¤¤¤Ê¤±¤ì¤Ð ¤Ê¤é¤Ê¤¤ÅÀ¤ËÃí°Õ¤¹¤ë¤³¤È¡£old_size ¤Ï¸µ¤Î²¾ÁÛ¥á¥â¥ê¡¦¥Ö¥í¥Ã¥¯¤Î ¥µ¥¤¥º¤Ç¤¢¤ë¡£ new_size ¤ÏÍ׵᤹¤ëÊѹ¹¸å¤Î²¾ÁÛ¥á¥â¥ê¡¦¥Ö¥í¥Ã¥¯¤Î¥µ¥¤¥º¤Ç¤¢¤ë¡£

Linux ¤Ç¤Ï¥á¥â¥ê¤Ï¥Ú¡¼¥¸¤Ëʬ³ä¤µ¤ì¤ë¡£¥æ¡¼¥¶¡¼¡¦¥×¥í¥»¥¹¤Ï (°ì¤Ä¤Þ¤¿¤Ï) Ê£¿ô¤Î¥ê¥Ë¥¢¤Ê²¾ÁÛ¥á¥â¥ê¥»¥°¥á¥ó¥È¤ò»ý¤Ä¡£ ¤½¤ì¤¾¤ì¤Î²¾ÁÛ¥á¥â¥ê¥»¥°¥á¥ó¥È¤Ï°ì¤Ä°Ê¾å¤Î¼Â¥á¥â¥ê¡¦¥Ú¡¼¥¸ ¤Ë¥Þ¥Ã¥Ô¥ó¥°¤µ¤ì¤Æ¤¤¤ë (¥Þ¥Ã¥Ô¥ó¥°¾ðÊó¤Ï¥Ú¡¼¥¸¡¦¥Æ¡¼¥Ö¥ë¤Ç´ÉÍý¤µ¤ì¤ë)¡£ ²¾ÁÛ¥á¥â¥ê¥»¥°¥á¥ó¥È¤Ë¤Ï¥»¥°¥á¥ó¥ÈËè¤ÎÊݸî (¥¢¥¯¥»¥¹¸¢) ¤¬ÀßÄꤵ¤ì¤Æ¤ª¤ê¡¢ ¥á¥â¥ê¤¬ÉÔÀµ¤Ë¥¢¥¯¥»¥¹¤µ¤ì¤¿¾ì¹ç (Î㤨¤ÐÆɤ߹þ¤ßÀìÍѤΥ»¥°¥á¥ó¥È¤Ë ½ñ¤­¹þ¤ó¤À¾ì¹ç)¡¢¥»¥°¥á¥ó¥Æ¡¼¥·¥ç¥ó¿¯³² (segmentation violation) ¤ò °ú¤­µ¯¤³¤¹¡£¤Þ¤¿¡¢¥»¥°¥á¥ó¥È³°¤Î²¾ÁÛ¥á¥â¥ê¤Ë¥¢¥¯¥»¥¹¤·¤¿¾ì¹ç¤Ë¤â ¥»¥°¥á¥ó¥Æ¡¼¥·¥ç¥ó¿¯³²¤¬È¯À¸¤¹¤ë¡£

mremap() ¤Ï Linux ¤Î¥Ú¡¼¥¸¡¦¥Æ¡¼¥Ö¥ëÊý¼°¤ò»ÈÍѤ¹¤ë¡£ mremap() ¤Ï²¾ÁÛ¥¢¥É¥ì¥¹¤È¥á¥â¥ê¡¦¥Ú¡¼¥¸¤Î¥Þ¥Ã¥Ô¥ó¥°¤òÊѹ¹¤¹¤ë¡£¤³¤ì¤ÏÈó¾ï¤Ë¸úΨŪ¤Ê realloc(3) ¤ò¼ÂÁõ¤¹¤ë¤Î¤Ë»ÈÍѤµ¤ì¤Æ¤¤¤ë¡£

flags ¥Ó¥Ã¥È¥Þ¥¹¥¯°ú¿ô¤Ï 0 ¤Þ¤¿¤Ï°Ê²¼¤Î¥Õ¥é¥°¤ò´Þ¤à:

MREMAP_MAYMOVE

¥Ç¥Õ¥©¥ë¥È¤Ç¤Ï¡¢¸½ºß¤Î°ÌÃ֤˥ޥåԥ󥰤ò³ÈÄ¥¤¹¤ë¤¿¤á¤Î ½½Ê¬¤Ê¶õ¤­¤¬¤Ê¤±¤ì¤Ð mremap() ¤Ï¼ºÇÔ¤¹¤ë¡£ ¤³¤Î¥Õ¥é¥°¤¬»ØÄꤵ¤ì¤ë¤È¡¢¥«¡¼¥Í¥ë¤ÏɬÍפ¬¤¢¤ì¤Ð¥Þ¥Ã¥Ô¥ó¥°¤ò ¿·¤·¤¤²¾ÁÛ¥¢¥É¥ì¥¹¤ËºÆÇÛÃÖ¤¹¤ë¤³¤È¤¬¤Ç¤­¤ë ¥Þ¥Ã¥Ô¥ó¥°¤¬ºÆÇÛÃÖ¤µ¤ì¤ë¤È¡¢¸Å¤¤¥Þ¥Ã¥Ô¥ó¥°°ÌÃ֤ؤÎÀäÂХݥ¤¥ó¥¿¤Ï ̵¸ú¤Ë¤Ê¤ë (¥Þ¥Ã¥Ô¥ó¥°¤Î³«»Ï¥¢¥É¥ì¥¹¤«¤é¤ÎÁêÂÐ¥ª¥Õ¥»¥Ã¥È¤ÏÍ­¸ú¤Î¤Þ¤Þ¤Ç¤¢¤ë)¡£

MREMAP_FIXED (Linux 2.3.31 °Ê¹ß)

¤³¤Î¥Õ¥é¥°¤Ï mmap(2) ¤Î MAP_FIXED ¥Õ¥é¥°¤È»÷¤¿¤è¤¦¤ÊÌÜŪ¤ÇÍѤ¤¤é¤ì¤ë¡£ ¤³¤Î¥Õ¥é¥°¤¬»ØÄꤵ¤ì¤ë¤È¡¢ mremap() ¤Ï 5 ÈÖÌܤΰú¤­¿ô void *new_address ¤ò¼õ¤±¼è¤ê¡¢¤³¤Î°ú¿ô¤Ï¥Þ¥Ã¥Ô¥ó¥°¤¬°ÜÆ°¤µ¤ì¤ë¤Ù¤­¥¢¥É¥ì¥¹¤ò»ØÄꤹ¤ë¡£ ¤³¤Î¥¢¥É¥ì¥¹¤Ï¥Ú¡¼¥¸¶­³¦¤Ë¹ç¤Ã¤Æ¤¤¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£ new_address ¤È new_size ¤Ç»ØÄꤵ¤ì¤ë¥¢¥É¥ì¥¹ÈϰϤ˲áµî¤Î¥Þ¥Ã¥Ô¥ó¥°¤¬¤¢¤Ã¤¿¾ì¹ç¡¢ ¤½¤Î¥Þ¥Ã¥Ô¥ó¥°¤Ï¥¢¥ó¥Þ¥Ã¥×¤µ¤ì¤ë (unmapped)¡£ MREMAP_FIXED ¤ò»ØÄꤷ¤¿¾ì¹ç¤Ï¡¢ MREMAP_MAYMOVE ¤â»ØÄꤷ¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£

old_address ¤È old_size ¤Ç»ØÄꤵ¤ì¤ë¥á¥â¥ê¥»¥°¥á¥ó¥È¤¬ (mlock(2) ¤äƱÍͤΤâ¤Î¤Ç) ¥í¥Ã¥¯¤µ¤ì¤Æ¤¤¤ë¾ì¹ç¡¢¥»¥°¥á¥ó¥È¤Î¥µ¥¤¥º¤¬ÊѤï¤Ã¤¿¤ê ºÆÇÛÃÖ¤µ¤ì¤¿¤ê¤·¤¿»þ¤Ë¥í¥Ã¥¯¤â°Ý»ý¤µ¤ì¤ë¡£ ¤½¤Î·ë²Ì¡¢¥×¥í¥»¥¹¤Ë¤è¤Ã¤Æ¥í¥Ã¥¯¤µ¤ì¤ë¥á¥â¥ê¤ÎÎ̤ÏÊѲ½¤¹¤ë¡£

ÊÖ¤êÃÍ

À®¸ù¤·¤¿¾ì¹ç¤Ï mremap() ¤Ï¿·¤·¤¤²¾ÁÛ¥á¥â¥êÎΰè¤Ø¤Î¥Ý¥¤¥ó¥¿¤òÊÖ¤¹¡£ ¥¨¥é¡¼¤Î¾ì¹ç¤Ï MAP_FAILED (¤¹¤Ê¤ï¤Á (void *) -1) ¤¬ÊÖ¤µ¤ì¡¢errno ¤¬Å¬ÀÚ¤ËÀßÄꤵ¤ì¤ë¡£

¥¨¥é¡¼

EAGAIN

¸Æ¤Ó½Ð¤·¸µ¤¬¥í¥Ã¥¯¤µ¤ì¤Æ¤¤¤ë¥á¥â¥ê¥»¥°¥á¥ó¥È¤ò³ÈÄ¥¤·¤è¤¦¤È¤·¤¿¤¬¡¢ RLIMIT_MEMLOCK ¥ê¥½¡¼¥¹À©¸Â¤ò±Û¤¨¤º¤Ë¤³¤ì¤ò¹Ô¤¦¤³¤È¤¬¤Ç¤­¤Ê¤¤¡£

EFAULT

¡Ö¥»¥°¥á¥ó¥Æ¡¼¥·¥ç¥ó°ãÈ¿(segmentation fault)¡× old_address ¤«¤é old_address+old_size ¤Î ÈϰϤΥ¢¥É¥ì¥¹¤Î¤É¤ì¤«¤¬¤³¤Î¥×¥í¥»¥¹¤Ë¤ª¤¤¤ÆÉÔÀµ¤Ê²¾ÁÛ¥á¥â¥ê¡¦¥¢¥É¥ì¥¹¤Ç¤¢¤ë¡£ ¤¿¤È¤¨Í׵ᤷ¤¿¥¢¥É¥ì¥¹¶õ´ÖÁ´ÂΤò´Þ¤à¤è¤¦¤Ê¥Þ¥Ã¥Ô¥ó¥°¤¬¤¢¤Ã¤¿¤È¤·¤Æ¤â¡¢ ¤½¤ì¤é¤Î¥Þ¥Ã¥Ô¥ó¥°¤¬°Û¤Ê¤Ã¤¿·¿¤Ê¤é¤Ð EFAULT ¤ò¼õ¤±¼è¤ë¤À¤í¤¦¡£

EINVAL

ÉÔÀµ¤Ê°ú¤­¿ô¤¬Í¿¤¨¤é¤ì¤¿¡£ ²ÄǽÀ­¤Î¤¢¤ë¸¶°ø¤Ï°Ê²¼¤ÎÄ̤ê¤Ç¤¢¤ë: ¤¿¤¤¤Æ¤¤¤Ï old_address ¤¬¥Ú¡¼¥¸¶­³¦¤Ë ¹ç¤Ã¤Æ¤Ê¤¤; flags ¤Ë MREMAP_MAYMOVE ¤Þ¤¿¤Ï MREMAP_FIXED °Ê³°¤ÎÃͤ¬»ØÄꤵ¤ì¤Æ¤¤¤ë; new_size ¤¬¥¼¥í; new_size ¤Þ¤¿¤Ï new_address ¤ÎÃͤ¬ÉÔÀµ; new_address ¤È new_size ¤Ç»ØÄꤵ¤ì¤ë¿·¤·¤¤¥¢¥É¥ì¥¹ÈϰϤ¬ old_address ¤È old_size ¤Ç»ØÄꤵ¤ì¤ë¸Å¤¤¥¢¥É¥ì¥¹ÈϰϤȽŤʤäƤ¤¤ë; MREMAP_FIXED ¤¬»ØÄꤵ¤ì¤Æ¤¤¤ë¤¬ MREMAP_MAYMOVE ¤¬»ØÄꤵ¤ì¤Æ¤¤¤Ê¤¤¡£

ENOMEM

¸½ºß¤Î²¾ÁÛ¥¢¥É¥ì¥¹¤Ç¤Ï¥á¥â¥êÎΰ褬³ÈÄ¥¤Ç¤­¤º¡¢ MREMAP_MAYMOVE ¥Õ¥é¥°¤¬ flags ¤ËÀßÄꤵ¤ì¤Æ¤¤¤Ê¤¤¡£ ¤Þ¤¿¤Ï½½Ê¬¤Ê (²¾ÁÛ) ¥á¥â¥ê¤¬Â¸ºß¤·¤Ê¤¤¡£

½àµò

¤³¤Î¥³¡¼¥ë¤Ï Linux ÆÃÍ­¤Ç¤¢¤ê¡¢°Ü¿¢¤ò°Õ¿Þ¤·¤¿¥×¥í¥°¥é¥à¤Ç »ÈÍѤ¹¤Ù¤­¤Ç¤Ï¤Ê¤¤¡£

Ãí°Õ

¥Ð¡¼¥¸¥ç¥ó 2.4 ¤è¤êÁ°¤Î glibc ¤Ç¤Ï¡¢ MREMAP_FIXED ¤ÎÄêµÁ¤Ï¸ø³«¤µ¤ì¤Æ¤ª¤é¤º¡¢ mremap() ¤Î¥×¥í¥È¥¿¥¤¥×¤Ï new_address °ú¤­¿ô¤ò¼è¤é¤Ê¤«¤Ã¤¿¡£

´ØÏ¢¹àÌÜ

brk(2), getpagesize(2), getrlimit(2), mlock(2), mmap(2), sbrk(2), realloc(3), malloc(3), feature_test_macros(7) ¥Ú¡¼¥¸Ê¬³ä¤µ¤ì¤¿¥á¥â¥ê¤Ë¤Ä¤¤¤Æ¤â¤Ã¤È¾Ü¤·¤¯ÃΤꤿ¤¤¤Ê¤é¤Ð ¤¢¤Ê¤¿¤Î¹¥¤ß¤Î OS ¤Î¶µ²Ê½ñ¤ò»²¾È¤¹¤ë¤³¤È¡£ (Modern Operating Systems by Andrew S. Tannenbaum, Inside Linux by Randolf Bentson, The Design of the UNIX Operating System by Maurice J. Bach.)