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glibc  2.9
brk.c
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00001 /* brk system call for Linux/i386.
00002    Copyright (C) 1995, 1996, 2000, 2002, 2003 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <errno.h>
00021 #include <unistd.h>
00022 #include <sysdep.h>
00023 
00024 #include <bp-checks.h>
00025 
00026 /* This must be initialized data because commons can't have aliases.  */
00027 void *__curbrk = 0;
00028 
00029 /* Old braindamage in GCC's crtstuff.c requires this symbol in an attempt
00030    to work around different old braindamage in the old Linux ELF dynamic
00031    linker.  */
00032 weak_alias (__curbrk, ___brk_addr)
00033 
00034 int
00035 __brk (void *addr)
00036 {
00037   void *__unbounded newbrk;
00038 
00039   INTERNAL_SYSCALL_DECL (err);
00040   newbrk = (void *__unbounded) INTERNAL_SYSCALL (brk, err, 1,
00041                                            __ptrvalue (addr));
00042 
00043   __curbrk = newbrk;
00044 
00045   if (newbrk < addr)
00046     {
00047       __set_errno (ENOMEM);
00048       return -1;
00049     }
00050 
00051   return 0;
00052 }
00053 weak_alias (__brk, brk)