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56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
/* brk system call for Linux/i386.
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Copyright (C) 1995, 1996 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <errno.h>
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#include <unistd.h>
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#include <sysdep.h>
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/* This must be initialized data because commons can't have aliases. */
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void *__curbrk = 0;
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/* Old braindamage in GCC's crtstuff.c requires this symbol in an attempt
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to work around different old braindamage in the old Linux ELF dynamic
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linker. */
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weak_alias (__curbrk, ___brk_addr)
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int
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__brk (void *addr)
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{
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void *newbrk, *scratch;
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asm ("movl %%ebx, %1\n" /* Save %ebx in scratch register. */
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"movl %3, %%ebx\n" /* Put ADDR in %ebx to be syscall arg. */
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"int $0x80 # %2\n" /* Perform the system call. */
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"movl %1, %%ebx\n" /* Restore %ebx from scratch register. */
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: "=a" (newbrk), "=r" (scratch)
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: "0" (SYS_ify (brk)), "g" (addr));
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__curbrk = newbrk;
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if (newbrk < addr)
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{
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errno = ENOMEM;
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return -1;
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}
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return 0;
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}
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weak_alias (__brk, brk)
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