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From: Neil Booth <neil@daikokuya.demon.co.uk> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, Subject: Re: bootstrap/5149: gcc-20011217 reads beyond EOF on cygwin Date: Thu, 20 Dec 2001 10:36:00 -0000 [thread overview] Message-ID: <20011220183600.20035.qmail@sources.redhat.com> (raw) The following reply was made to PR bootstrap/5149; it has been noted by GNATS. From: Neil Booth <neil@daikokuya.demon.co.uk> To: Werner Tuchan <tuwn@gmx.net> Cc: neil@gcc.gnu.org, gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org Subject: Re: bootstrap/5149: gcc-20011217 reads beyond EOF on cygwin Date: Thu, 20 Dec 2001 18:33:23 +0000 Werner Tuchan wrote:- > Thats the piece of code that loaded the file, this time its libgcc2.c. > > cppfiles.c > 388 /* Use mmap if the file is big enough to be worth it (controlled > 389 by MMAP_THRESHOLD) and if we can safely count on there being > 390 at least one readable NUL byte after the end of the file's > 391 contents. This is true for all tested operating systems when > 392 the file size is not an exact multiple of the page size. */ > - 393 if (size / pagesize >= MMAP_THRESHOLD > 394 && (size % pagesize) != 0) > 395 { > - 396 buf = (U_CHAR *) mmap (0, size, PROT_READ, MAP_PRIVATE, inc->fd, > 0); > - 397 if (buf == (U_CHAR *)-1) > 398 goto perror_fail; > - 399 inc->mapped = 1; > - 400 } > 401 else > 402 #endif Cool, this is useful, thanks. > (gdb) x /s buf + 46170 > 0x83a5445a: "ED_ATEXIT */\n\n#endif /* L_exit */\n" > > (gdb) x /100xb buf + 46170 > 0x83a5445a: 0x45 0x44 0x5f 0x41 0x54 0x45 0x58 0x49 > 0x83a54462: 0x54 0x20 0x2a 0x2f 0x0a 0x0a 0x23 0x65 > 0x83a5446a: 0x6e 0x64 0x69 0x66 0x20 0x2f 0x2a 0x20 > 0x83a54472: 0x4c 0x5f 0x65 0x78 0x69 0x74 0x20 0x2a > 0x83a5447a: 0x2f 0x0a 0xc0 0xc0 0xc0 0x00 0xc0 0xc0 > 0x83a54482: 0xc0 0x00 0xc0 0xc0 0xc0 0x00 0xc0 0xc0 > 0x83a5448a: 0xc0 0x00 0xc0 0xc0 0xc0 0x00 0xc0 0xc0 > 0x83a54492: 0xc0 0x00 0xc0 0xc0 0xc0 0x00 0xc0 0xc0 > 0x83a5449a: 0xc0 0x00 0x00 0x00 0x00 0x00 0x00 0x00 > 0x83a544a2: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 > 0x83a544aa: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 > 0x83a544b2: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 > 0x83a544ba: 0x00 0x00 0x00 0x00 Weird. The bytes after EOF are a mixture of NULs and 0xc0. Is 0xc0 of special significance in Windows? Is your version of cygwin the latest? I recall some talk about mmap bugs in cygwin. I guess that we have to disable mmap() on cygwin, or at least on specific versions. Do you have any better ideas Zack? Neil.
next reply other threads:[~2001-12-20 18:36 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2001-12-20 10:36 Neil Booth [this message] -- strict thread matches above, loose matches on Subject: below -- 2002-06-19 4:26 neil 2001-12-21 23:36 Zack Weinberg 2001-12-21 10:56 Neil Booth 2001-12-21 9:26 Christopher Faylor 2001-12-21 6:46 Werner Tuchan 2001-12-20 11:16 Neil Booth 2001-12-20 11:06 Zack Weinberg 2001-12-20 6:46 Werner Tuchan 2001-12-19 16:20 neil 2001-12-18 3:56 tuwn
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