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Remove some pre-2.6.0 Linux kernel conditionals
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: <libc-alpha at sourceware dot org>
- Date: Fri, 3 Aug 2012 14:34:07 +0000
- Subject: Remove some pre-2.6.0 Linux kernel conditionals
This patch does the straightforward part of cleaning up conditionals
that are no longer needed now 2.6.0 is the minimum Linux kernel
version, by removing the four macros __ASSUME_AT_SECURE,
__ASSUME_CORRECT_SI_PID, __ASSUME_BRK_PAGE_ROUNDED and
__ASSUME_TMPFS_NAME. In all four cases the macro was defined for all
architectures, and only tested in one file, architecture-independent,
in such a way that the conditionals were straightforward to remove.
Tested x86_64.
2012-08-03 Joseph Myers <joseph@codesourcery.com>
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_AT_SECURE):
Remove.
(__ASSUME_CORRECT_SI_PID): Likewise.
(__ASSUME_BRK_PAGE_ROUNDED): Likewise.
(__ASSUME_TMPFS_NAME): Likewise.
* sysdeps/unix/sysv/linux/dl-sysdep.c (frob_brk)
[!__ASSUME_BRK_PAGE_ROUNDED]: Remove conditional code.
* sysdeps/unix/sysv/linux/ldsodefs.h [__ASSUME_AT_SECURE]
(HAVE_AUX_SECURE): Make definition unconditional.
* sysdeps/unix/sysv/linux/shm_open.c (where_is_shmfs)
[!__ASSUME_TMPFS_NAME]: Remove conditional code.
nptl/ChangeLog:
2012-08-03 Joseph Myers <joseph@codesourcery.com>
* nptl-init.c (sigcancel_handler) [__ASSUME_CORRECT_SI_PID]: Make
code unconditional.
(sighandler_setxid) [__ASSUME_CORRECT_SI_PID]: Likewise.
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index 5216ce1..6a18dbe 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -172,24 +172,18 @@ __nptl_set_robust (struct pthread *self)
static void
sigcancel_handler (int sig, siginfo_t *si, void *ctx)
{
-#ifdef __ASSUME_CORRECT_SI_PID
/* Determine the process ID. It might be negative if the thread is
in the middle of a fork() call. */
pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
if (__builtin_expect (pid < 0, 0))
pid = -pid;
-#endif
/* Safety check. It would be possible to call this function for
other signals and send a signal from another process. This is not
correct and might even be a security problem. Try to catch as
many incorrect invocations as possible. */
if (sig != SIGCANCEL
-#ifdef __ASSUME_CORRECT_SI_PID
- /* Kernels before 2.5.75 stored the thread ID and not the process
- ID in si_pid so we skip this test. */
|| si->si_pid != pid
-#endif
|| si->si_code != SI_TKILL)
return;
@@ -235,24 +229,18 @@ struct xid_command *__xidcmd attribute_hidden;
static void
sighandler_setxid (int sig, siginfo_t *si, void *ctx)
{
-#ifdef __ASSUME_CORRECT_SI_PID
/* Determine the process ID. It might be negative if the thread is
in the middle of a fork() call. */
pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
if (__builtin_expect (pid < 0, 0))
pid = -pid;
-#endif
/* Safety check. It would be possible to call this function for
other signals and send a signal from another process. This is not
correct and might even be a security problem. Try to catch as
many incorrect invocations as possible. */
if (sig != SIGSETXID
-#ifdef __ASSUME_CORRECT_SI_PID
- /* Kernels before 2.5.75 stored the thread ID and not the process
- ID in si_pid so we skip this test. */
|| si->si_pid != pid
-#endif
|| si->si_code != SI_TKILL)
return;
diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c
index 42c63d2..da3686a 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) 1995,1997,2001,2004,2005,2006, 2008 Free Software Foundation, Inc.
+ Copyright (C) 1995-2012 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
@@ -33,27 +33,6 @@ 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 char *__curbrk attribute_hidden;
- extern char _end[] attribute_hidden;
- char *const endpage = (void *) 0 + (((__curbrk - (char *) 0)
- + GLRO(dl_pagesize) - 1)
- & -GLRO(dl_pagesize));
- if (__builtin_expect (__curbrk >= _end && __curbrk < endpage, 0))
- __brk (endpage);
-#endif
}
# include <elf/dl-sysdep.c>
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index b949f16..e5b65cc 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -115,15 +115,6 @@
/* The statfs64 syscalls are available in 2.5.74 (but not for alpha). */
#define __ASSUME_STATFS64 1
-/* Starting with at least 2.5.74 the kernel passes the setuid-like exec
- flag unconditionally up to the child. */
-#define __ASSUME_AT_SECURE 1
-
-/* Starting with the 2.5.75 kernel the kernel fills in the correct value
- in the si_pid field passed as part of the siginfo_t struct to signal
- handlers. */
-#define __ASSUME_CORRECT_SI_PID 1
-
/* The tgkill syscall was instroduced for i386 in 2.5.75. On x86-64,
sparc, SH, ppc, and ppc64 it was introduced in 2.6.0-test3. */
#if defined __i386__ \
@@ -189,10 +180,6 @@
# 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. */
-#define __ASSUME_BRK_PAGE_ROUNDED 1
-
/* Starting with version 2.6.9, the waitid system call is available.
Except for powerpc{,64} and s390{,x}, where it is available in 2.6.12. */
#if (__LINUX_KERNEL_VERSION >= 0x020609 \
@@ -208,11 +195,6 @@
# define __ASSUME_STAT64_SYSCALL 1
#endif
-/* Early kernel used "shm" as the filesystem name for the filesystem used
- for shm_open etc. Later it is "tmpfs". 2.4.20 is a safe bet for the
- cutover. */
-#define __ASSUME_TMPFS_NAME 1
-
/* pselect/ppoll were introduced just after 2.6.16-rc1. Due to the way
the kernel versions are advertised we can only rely on 2.6.17 to have
the code. On x86_64 and SH this appeared first in 2.6.19-rc1,
diff --git a/sysdeps/unix/sysv/linux/ldsodefs.h b/sysdeps/unix/sysv/linux/ldsodefs.h
index 50f3e2b..cf7ace7 100644
--- a/sysdeps/unix/sysv/linux/ldsodefs.h
+++ b/sysdeps/unix/sysv/linux/ldsodefs.h
@@ -41,9 +41,7 @@ extern void _dl_non_dynamic_init (void) internal_function;
/* We can assume that the kernel always provides the AT_SECURE value
in the auxiliary vector from 2.5.74 or so on. */
-#if __ASSUME_AT_SECURE
-# define HAVE_AUX_SECURE
-#endif
+#define HAVE_AUX_SECURE
/* Starting with one of the 2.4.0 pre-releases the Linux kernel passes
up the page size information. */
diff --git a/sysdeps/unix/sysv/linux/shm_open.c b/sysdeps/unix/sysv/linux/shm_open.c
index 763b087..82332a3 100644
--- a/sysdeps/unix/sysv/linux/shm_open.c
+++ b/sysdeps/unix/sysv/linux/shm_open.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2000-2004,2006,2007 Free Software Foundation, Inc.
+/* Copyright (C) 2000-2012 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
@@ -86,11 +86,7 @@ where_is_shmfs (void)
while ((mp = __getmntent_r (fp, &resmem, buf, sizeof buf)) != NULL)
/* The original name is "shm" but this got changed in early Linux
2.4.x to "tmpfs". */
- if (strcmp (mp->mnt_type, "tmpfs") == 0
-#ifndef __ASSUME_TMPFS_NAME
- || strcmp (mp->mnt_type, "shm") == 0
-#endif
- )
+ if (strcmp (mp->mnt_type, "tmpfs") == 0)
{
/* Found it. There might be more than one place where the
filesystem is mounted but one is enough for us. */
--
Joseph S. Myers
joseph@codesourcery.com