diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/unix/sysv/linux/dl-sysdep.c | 25 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/kernel-features.h | 6 |
2 files changed, 30 insertions, 1 deletions
diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c index b58f4c13e2..79f95df0a2 100644 --- a/sysdeps/unix/sysv/linux/dl-sysdep.c +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c @@ -1,5 +1,5 @@ /* Dynamic linker system dependencies for Linux. - Copyright (C) 1995, 1997, 2001 Free Software Foundation, Inc. + Copyright (C) 1995, 1997, 2001, 2004 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -21,6 +21,8 @@ the generic dynamic linker system interface code. */ #include <unistd.h> +#include <ldsodefs.h> +#include "kernel-features.h" #define DL_SYSDEP_INIT frob_brk () @@ -28,6 +30,27 @@ static inline void frob_brk (void) { __brk (0); /* Initialize the break. */ + +#if ! __ASSUME_BRK_PAGE_ROUNDED + /* If the dynamic linker was executed as a program, then the break may + start immediately after our data segment. However, dl-minimal.c has + already stolen the remainder of the page for internal allocations. + If we don't adjust the break location recorded by the kernel, the + normal program startup will inquire, find the value at our &_end, + and start allocating its own data there, clobbering dynamic linker + data structures allocated there during startup. + + Later Linux kernels have changed this behavior so that the initial + break value is rounded up to the page boundary before we start. */ + + extern void *__curbrk attribute_hidden; + extern void _end attribute_hidden; + void *const endpage = (void *) 0 + (((__curbrk - (void *) 0) + + GLRO(dl_pagesize) - 1) + & -GLRO(dl_pagesize)); + if (__builtin_expect (__curbrk >= &_end && __curbrk < endpage, 0)) + __brk (endpage); +#endif } #include <sysdeps/generic/dl-sysdep.c> diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h index ee089d550b..6f19fc6360 100644 --- a/sysdeps/unix/sysv/linux/kernel-features.h +++ b/sysdeps/unix/sysv/linux/kernel-features.h @@ -400,3 +400,9 @@ #if __LINUX_KERNEL_VERSION >= 132612 # define __ASSUME_GETDENTS32_D_TYPE 1 #endif + +/* Starting with version 2.5.3, the initial location returned by `brk' + after exec is always rounded up to the next page. */ +#if __LINUX_KERNEL_VERSION >= 132355 +# define __ASSUME_BRK_PAGE_ROUNDED 1 +#endif |