The strscpy() API is intended to be used instead of strlcpy(),
and instead of most uses of strncpy().
- Unlike strlcpy(), it doesn't read from memory beyond (src + size).
- Unlike strlcpy() or strncpy(), the API provides an easy way to check
for destination buffer overflow: an -E2BIG error return value.
- The provided implementation is robust in the face of the source
buffer being asynchronously changed during the copy, unlike the
current implementation of strlcpy().
- Unlike strncpy(), the destination buffer will be NUL-terminated
if the string in the source buffer is too long.
- Also unlike strncpy(), the destination buffer will not be updated
beyond the NUL termination, avoiding strncpy's behavior of zeroing
the entire tail end of the destination buffer. (A memset() after
the strscpy() can be used if this behavior is desired.)
- The implementation should be reasonably performant on all
platforms since it uses the asm/word-at-a-time.h API rather than
simple byte copy. Kernel-to-kernel string copy is not considered
to be performance critical in any case.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Strings are sometimes sanitized by replacing a certain character (often
'/') by another (often '!'). In a few places, this is done the same way
Schlemiel the Painter would do it. Others are slightly smarter but still
do multiple strchr() calls. Introduce strreplace() to do this using a
single function call and a single pass over the string.
One would expect the return value to be one of three things: void, s, or
the number of replacements made. I chose the fourth, returning a pointer
to the end of the string. This is more likely to be useful (for example
allowing the caller to avoid a strlen call).
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In commit 0b053c9518 ("lib: memzero_explicit: use barrier instead
of OPTIMIZER_HIDE_VAR"), we made memzero_explicit() more robust in
case LTO would decide to inline memzero_explicit() and eventually
find out it could be elimiated as dead store.
While using barrier() works well for the case of gcc, recent efforts
from LLVMLinux people suggest to use llvm as an alternative to gcc,
and there, Stephan found in a simple stand-alone user space example
that llvm could nevertheless optimize and thus elimitate the memset().
A similar issue has been observed in the referenced llvm bug report,
which is regarded as not-a-bug.
Based on some experiments, icc is a bit special on its own, while it
doesn't seem to eliminate the memset(), it could do so with an own
implementation, and then result in similar findings as with llvm.
The fix in this patch now works for all three compilers (also tested
with more aggressive optimization levels). Arguably, in the current
kernel tree it's more of a theoretical issue, but imho, it's better
to be pedantic about it.
It's clearly visible with gcc/llvm though, with the below code: if we
would have used barrier() only here, llvm would have omitted clearing,
not so with barrier_data() variant:
static inline void memzero_explicit(void *s, size_t count)
{
memset(s, 0, count);
barrier_data(s);
}
int main(void)
{
char buff[20];
memzero_explicit(buff, sizeof(buff));
return 0;
}
$ gcc -O2 test.c
$ gdb a.out
(gdb) disassemble main
Dump of assembler code for function main:
0x0000000000400400 <+0>: lea -0x28(%rsp),%rax
0x0000000000400405 <+5>: movq $0x0,-0x28(%rsp)
0x000000000040040e <+14>: movq $0x0,-0x20(%rsp)
0x0000000000400417 <+23>: movl $0x0,-0x18(%rsp)
0x000000000040041f <+31>: xor %eax,%eax
0x0000000000400421 <+33>: retq
End of assembler dump.
$ clang -O2 test.c
$ gdb a.out
(gdb) disassemble main
Dump of assembler code for function main:
0x00000000004004f0 <+0>: xorps %xmm0,%xmm0
0x00000000004004f3 <+3>: movaps %xmm0,-0x18(%rsp)
0x00000000004004f8 <+8>: movl $0x0,-0x8(%rsp)
0x0000000000400500 <+16>: lea -0x18(%rsp),%rax
0x0000000000400505 <+21>: xor %eax,%eax
0x0000000000400507 <+23>: retq
End of assembler dump.
As gcc, clang, but also icc defines __GNUC__, it's sufficient to define
this in compiler-gcc.h only to be picked up. For a fallback or otherwise
unsupported compiler, we define it as a barrier. Similarly, for ecc which
does not support gcc inline asm.
Reference: https://llvm.org/bugs/show_bug.cgi?id=15495
Reported-by: Stephan Mueller <smueller@chronox.de>
Tested-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Stephan Mueller <smueller@chronox.de>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: mancha security <mancha1@zoho.com>
Cc: Mark Charlebois <charlebm@gmail.com>
Cc: Behan Webster <behanw@converseincode.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
OPTIMIZER_HIDE_VAR(), as defined when using gcc, is insufficient to
ensure protection from dead store optimization.
For the random driver and crypto drivers, calls are emitted ...
$ gdb vmlinux
(gdb) disassemble memzero_explicit
Dump of assembler code for function memzero_explicit:
0xffffffff813a18b0 <+0>: push %rbp
0xffffffff813a18b1 <+1>: mov %rsi,%rdx
0xffffffff813a18b4 <+4>: xor %esi,%esi
0xffffffff813a18b6 <+6>: mov %rsp,%rbp
0xffffffff813a18b9 <+9>: callq 0xffffffff813a7120 <memset>
0xffffffff813a18be <+14>: pop %rbp
0xffffffff813a18bf <+15>: retq
End of assembler dump.
(gdb) disassemble extract_entropy
[...]
0xffffffff814a5009 <+313>: mov %r12,%rdi
0xffffffff814a500c <+316>: mov $0xa,%esi
0xffffffff814a5011 <+321>: callq 0xffffffff813a18b0 <memzero_explicit>
0xffffffff814a5016 <+326>: mov -0x48(%rbp),%rax
[...]
... but in case in future we might use facilities such as LTO, then
OPTIMIZER_HIDE_VAR() is not sufficient to protect gcc from a possible
eviction of the memset(). We have to use a compiler barrier instead.
Minimal test example when we assume memzero_explicit() would *not* be
a call, but would have been *inlined* instead:
static inline void memzero_explicit(void *s, size_t count)
{
memset(s, 0, count);
<foo>
}
int main(void)
{
char buff[20];
snprintf(buff, sizeof(buff) - 1, "test");
printf("%s", buff);
memzero_explicit(buff, sizeof(buff));
return 0;
}
With <foo> := OPTIMIZER_HIDE_VAR():
(gdb) disassemble main
Dump of assembler code for function main:
[...]
0x0000000000400464 <+36>: callq 0x400410 <printf@plt>
0x0000000000400469 <+41>: xor %eax,%eax
0x000000000040046b <+43>: add $0x28,%rsp
0x000000000040046f <+47>: retq
End of assembler dump.
With <foo> := barrier():
(gdb) disassemble main
Dump of assembler code for function main:
[...]
0x0000000000400464 <+36>: callq 0x400410 <printf@plt>
0x0000000000400469 <+41>: movq $0x0,(%rsp)
0x0000000000400471 <+49>: movq $0x0,0x8(%rsp)
0x000000000040047a <+58>: movl $0x0,0x10(%rsp)
0x0000000000400482 <+66>: xor %eax,%eax
0x0000000000400484 <+68>: add $0x28,%rsp
0x0000000000400488 <+72>: retq
End of assembler dump.
As can be seen, movq, movq, movl are being emitted inlined
via memset().
Reference: http://thread.gmane.org/gmane.linux.kernel.cryptoapi/13764/
Fixes: d4c5efdb97 ("random: add and use memzero_explicit() for clearing data")
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: mancha security <mancha1@zoho.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull crypto update from Herbert Xu:
"Here is the crypto update for 3.20:
- Added 192/256-bit key support to aesni GCM.
- Added MIPS OCTEON MD5 support.
- Fixed hwrng starvation and race conditions.
- Added note that memzero_explicit is not a subsitute for memset.
- Added user-space interface for crypto_rng.
- Misc fixes"
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (71 commits)
crypto: tcrypt - do not allocate iv on stack for aead speed tests
crypto: testmgr - limit IV copy length in aead tests
crypto: tcrypt - fix buflen reminder calculation
crypto: testmgr - mark rfc4106(gcm(aes)) as fips_allowed
crypto: caam - fix resource clean-up on error path for caam_jr_init
crypto: caam - pair irq map and dispose in the same function
crypto: ccp - terminate ccp_support array with empty element
crypto: caam - remove unused local variable
crypto: caam - remove dead code
crypto: caam - don't emit ICV check failures to dmesg
hwrng: virtio - drop extra empty line
crypto: replace scatterwalk_sg_next with sg_next
crypto: atmel - Free memory in error path
crypto: doc - remove colons in comments
crypto: seqiv - Ensure that IV size is at least 8 bytes
crypto: cts - Weed out non-CBC algorithms
MAINTAINERS: add linux-crypto to hw random
crypto: cts - Remove bogus use of seqiv
crypto: qat - don't need qat_auth_state struct
crypto: algif_rng - fix sparse non static symbol warning
...
Instead of potentially passing over the string twice in case c is not
found, just keep track of the last occurrence. According to
bloat-o-meter, this also cuts the generated code by a third (54 vs 36
bytes). Oh, and we get rid of those 7-space indented lines.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that all in-tree users of strnicmp have been converted to
strncasecmp, the wrapper can be removed.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: David Howells <dhowells@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Lets improve the comment to add a note on when to use memzero_explicit()
for those not digging through the git logs. We don't want people to
pollute places with memzero_explicit() where it's not really necessary.
Reference: https://lkml.org/lkml/2015/1/4/190
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
optimized away by GCC. This is important when we are wiping
cryptographically sensitive material.
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Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random
Pull /dev/random updates from Ted Ts'o:
"This adds a memzero_explicit() call which is guaranteed not to be
optimized away by GCC. This is important when we are wiping
cryptographically sensitive material"
* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
crypto: memzero_explicit - make sure to clear out sensitive data
random: add and use memzero_explicit() for clearing data
zatimend has reported that in his environment (3.16/gcc4.8.3/corei7)
memset() calls which clear out sensitive data in extract_{buf,entropy,
entropy_user}() in random driver are being optimized away by gcc.
Add a helper memzero_explicit() (similarly as explicit_bzero() variants)
that can be used in such cases where a variable with sensitive data is
being cleared out in the end. Other use cases might also be in crypto
code. [ I have put this into lib/string.c though, as it's always built-in
and doesn't need any dependencies then. ]
Fixes kernel bugzilla: 82041
Reported-by: zatimend@hotmail.co.uk
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
The previous patch made strnicmp into a wrapper for strncasecmp.
This patch makes all in-tree users of strnicmp call strncasecmp
directly, while still making sure that the strnicmp symbol can be used
by out-of-tree modules. It should be considered a temporary hack until
all in-tree callers have been converted.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/string.c contains two functions, strnicmp and strncasecmp, which do
roughly the same thing, namely compare two strings case-insensitively up
to a given bound. They have slightly different implementations, but the
only important difference is that strncasecmp doesn't handle len==0
appropriately; it effectively becomes strcasecmp in that case. strnicmp
correctly says that two strings are always equal in their first 0
characters.
strncasecmp is the POSIX name for this functionality. So rename the
non-broken function to the standard name. To minimize the impact on the
rest of the kernel (and since both are exported to modules), make strnicmp
a wrapper for strncasecmp.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It used to be an ad-hoc hack defined by the x86 version of
<asm/bitops.h> that enabled a couple of library routines to know whether
an integer multiply is faster than repeated shifts and additions.
This just makes it use the real Kconfig system instead, and makes x86
(which was the only architecture that did this) select the option.
NOTE! Even for x86, this really is kind of wrong. If we cared, we would
probably not enable this for builds optimized for netburst (P4), where
shifts-and-adds are generally faster than multiplies. This patch does
*not* change that kind of logic, though, it is purely a syntactic change
with no code changes.
This was triggered by the fact that we have other places that really
want to know "do I want to expand multiples by constants by hand or
not", particularly the hash generation code.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For strncpy() and friends the source string may or may not have an actual
NUL character at the end. The documentation is confusing in this because
it specifically mentions that you are passing a "NUL-terminated" string.
Wikipedia says that "C-string" is an alternative name we can use instead.
http://en.wikipedia.org/wiki/Null-terminated_string
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The strchrnul() variant helpfully returns a the end of the string
instead of a NULL if the requested character is not found. This can
simplify string parsing code since it doesn't need to expicitly check
for a NULL return. If a valid string pointer is passed in, then a valid
null terminated string will always come back out.
Signed-off-by: Grant Likely <grant.likely@linaro.org>
In LTO symbols implicitely referenced by the compiler need
to be visible. Earlier these symbols were visible implicitely
from being exported, but we disabled implicit visibility fo
EXPORTs when modules are disabled to improve code size. So
now these symbols have to be marked visible explicitely.
Do this for __stack_chk_fail (with stack protector)
and memcmp.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391845930-28580-10-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
"[PATCH 0/3] RFC - module.h usage cleanups in fs/ and lib/"
https://lkml.org/lkml/2012/2/29/589
--
Fix up files in fs/ and lib/ dirs to only use module.h if they really
need it.
These are trivial in scope vs. the work done previously. We now have
things where any few remaining cleanups can be farmed out to arch or
subsystem maintainers, and I have done so when possible. What is
remaining here represents the bits that don't clearly lie within a
single arch/subsystem boundary, like the fs dir and the lib dir.
Some duplicate includes arising from overlapping fixes from
independent subsystem maintainer submissions are also quashed.
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Merge tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
Pull cleanup of fs/ and lib/ users of module.h from Paul Gortmaker:
"Fix up files in fs/ and lib/ dirs to only use module.h if they really
need it.
These are trivial in scope vs the work done previously. We now have
things where any few remaining cleanups can be farmed out to arch or
subsystem maintainers, and I have done so when possible. What is
remaining here represents the bits that don't clearly lie within a
single arch/subsystem boundary, like the fs dir and the lib dir.
Some duplicate includes arising from overlapping fixes from
independent subsystem maintainer submissions are also quashed."
Fix up trivial conflicts due to clashes with other include file cleanups
(including some due to the previous bug.h cleanup pull).
* tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
lib: reduce the use of module.h wherever possible
fs: reduce the use of module.h wherever possible
includecheck: delete any duplicate instances of module.h
"[RFC - PATCH 0/7] consolidation of BUG support code."
https://lkml.org/lkml/2012/1/26/525
--
The changes shown here are to unify linux's BUG support under
the one <linux/bug.h> file. Due to historical reasons, we have
some BUG code in bug.h and some in kernel.h -- i.e. the support for
BUILD_BUG in linux/kernel.h predates the addition of linux/bug.h,
but old code in kernel.h wasn't moved to bug.h at that time. As
a band-aid, kernel.h was including <asm/bug.h> to pseudo link them.
This has caused confusion[1] and general yuck/WTF[2] reactions.
Here is an example that violates the principle of least surprise:
CC lib/string.o
lib/string.c: In function 'strlcat':
lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON'
make[2]: *** [lib/string.o] Error 1
$
$ grep linux/bug.h lib/string.c
#include <linux/bug.h>
$
We've included <linux/bug.h> for the BUG infrastructure and yet we
still get a compile fail! [We've not kernel.h for BUILD_BUG_ON.]
Ugh - very confusing for someone who is new to kernel development.
With the above in mind, the goals of this changeset are:
1) find and fix any include/*.h files that were relying on the
implicit presence of BUG code.
2) find and fix any C files that were consuming kernel.h and
hence relying on implicitly getting some/all BUG code.
3) Move the BUG related code living in kernel.h to <linux/bug.h>
4) remove the asm/bug.h from kernel.h to finally break the chain.
During development, the order was more like 3-4, build-test, 1-2.
But to ensure that git history for bisect doesn't get needless
build failures introduced, the commits have been reorderd to fix
the problem areas in advance.
[1] https://lkml.org/lkml/2012/1/3/90
[2] https://lkml.org/lkml/2012/1/17/414
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Merge tag 'bug-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
Pull <linux/bug.h> cleanup from Paul Gortmaker:
"The changes shown here are to unify linux's BUG support under the one
<linux/bug.h> file. Due to historical reasons, we have some BUG code
in bug.h and some in kernel.h -- i.e. the support for BUILD_BUG in
linux/kernel.h predates the addition of linux/bug.h, but old code in
kernel.h wasn't moved to bug.h at that time. As a band-aid, kernel.h
was including <asm/bug.h> to pseudo link them.
This has caused confusion[1] and general yuck/WTF[2] reactions. Here
is an example that violates the principle of least surprise:
CC lib/string.o
lib/string.c: In function 'strlcat':
lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON'
make[2]: *** [lib/string.o] Error 1
$
$ grep linux/bug.h lib/string.c
#include <linux/bug.h>
$
We've included <linux/bug.h> for the BUG infrastructure and yet we
still get a compile fail! [We've not kernel.h for BUILD_BUG_ON.] Ugh -
very confusing for someone who is new to kernel development.
With the above in mind, the goals of this changeset are:
1) find and fix any include/*.h files that were relying on the
implicit presence of BUG code.
2) find and fix any C files that were consuming kernel.h and hence
relying on implicitly getting some/all BUG code.
3) Move the BUG related code living in kernel.h to <linux/bug.h>
4) remove the asm/bug.h from kernel.h to finally break the chain.
During development, the order was more like 3-4, build-test, 1-2. But
to ensure that git history for bisect doesn't get needless build
failures introduced, the commits have been reorderd to fix the problem
areas in advance.
[1] https://lkml.org/lkml/2012/1/3/90
[2] https://lkml.org/lkml/2012/1/17/414"
Fix up conflicts (new radeon file, reiserfs header cleanups) as per Paul
and linux-next.
* tag 'bug-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
kernel.h: doesn't explicitly use bug.h, so don't include it.
bug: consolidate BUILD_BUG_ON with other bug code
BUG: headers with BUG/BUG_ON etc. need linux/bug.h
bug.h: add include of it to various implicit C users
lib: fix implicit users of kernel.h for TAINT_WARN
spinlock: macroize assert_spin_locked to avoid bug.h dependency
x86: relocate get/set debugreg fcns to include/asm/debugreg.
- Generate a 64-bit pattern more efficiently
memchr_inv needs to generate a 64-bit pattern filled with a target
character. The operation can be done by more efficient way.
- Don't call the slow check_bytes() if the memory area is 64-bit aligned
memchr_inv compares contiguous 64-bit words with the 64-bit pattern as
much as possible. The outside of the region is checked by check_bytes()
that scans for each byte. Unfortunately, the first 64-bit word is
unexpectedly scanned by check_bytes() even if the memory area is aligned
to a 64-bit boundary.
Both changes were originally suggested by Eric Dumazet.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include. Fix up any implicit
include dependencies that were being masked by module.h along
the way.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
With bug.h currently living right in linux/kernel.h there
are files that use BUG_ON and friends but are not including
the header explicitly. Fix them up so we can remove the
presence in kernel.h file.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Commit 84c95c9acf ("string: on strstrip(), first remove leading spaces
before running over str") improved the performance of the strim()
function.
Unfortunately this changed the semantics of strim() and broke my code.
Before the patch it was possible to use strim() without using the return
value for removing trailing spaces from strings that had either only
blanks or only trailing blanks.
Now this does not work any longer for strings that *only* have blanks.
Before patch: " " -> "" (empty string)
After patch: " " -> " " (no change)
I think we should remove your patch to restore the old behavior.
The description (lib/string.c):
* Note that the first trailing whitespace is replaced with a %NUL-terminator
=> The first trailing whitespace of a string that only has whitespace
characters is the first whitespace
The patch restores the old strim() semantics.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Andre Goddard Rosa <andre.goddard@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memchr_inv() is mainly used to check whether the whole buffer is filled
with just a specified byte.
The function name and prototype are stolen from logfs and the
implementation is from SLUB.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Acked-by: Joern Engel <joern@logfs.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a rename of the usr_strtobool proposal, which was a renamed,
relocated and fixed version of previous kstrtobool RFC
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Joe Perches <joe@perches.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It differs strstr() in that it limits the length to be searched
in the first string.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B4E8743.6030805@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Fix kernel-doc warnings (@arg name) in string.c::skip_spaces().
Warning(lib/string.c:347): No description found for parameter 'str'
Warning(lib/string.c:347): Excess function parameter 's' description in 'skip_spaces'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recently, We marked strstrip() as must_check. because it was frequently
misused and it should be checked. However, we found one exception.
scsi/ipr.c intentionally ignore return value of strstrip. Because it
wishes to keep the whitespace at the beginning.
Thus we need to keep with and without checked whitespace trim function.
This patch adds a new strim() and changes ipr.c to use it.
[akpm@linux-foundation.org: coding-style fixes]
Suggested-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
... so that strlen() iterates over a smaller string comprising of the
remaining characters only.
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On the following sentence:
while (*s && isspace(*s))
s++;
If *s == 0, isspace() evaluates to ((_ctype[*s] & 0x20) != 0), which
evaluates to ((0x08 & 0x20) != 0) which equals to 0 as well.
If *s == 1, we depend on isspace() result anyway. In other words,
"a char equals zero is never a space", so remove this check.
Also, *s != 0 is most common case (non-null string).
Fixed const return as noticed by Jan Engelhardt and James Bottomley.
Fixed unnecessary extra cast on strstrip() as noticed by Jan Engelhardt.
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Doing the strcmp return value as
signed char __res = *cs - *ct;
is wrong for two reasons. The subtraction can overflow because __res
doesn't use a type big enough. Moreover the compared bytes should be
interpreted as unsigned char as specified by POSIX.
The same problem is fixed in strncmp.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Michael Buesch <mb@bu3sch.de>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new sysfs_streq() string comparison function, which ignores
the trailing newlines found in sysfs inputs. By example:
sysfs_streq("a", "b") ==> false
sysfs_streq("a", "a") ==> true
sysfs_streq("a", "a\n") ==> true
sysfs_streq("a\n", "a") ==> true
This is intended to simplify parsing of sysfs inputs, letting them
avoid the need to manually strip off newlines from inputs.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A variety of (mostly) innocuous fixes to the embedded kernel-doc content in
source files, including:
* make multi-line initial descriptions single line
* denote some function names, constants and structs as such
* change erroneous opening '/*' to '/**' in a few places
* reword some text for clarity
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
strstrip() does not remove the last blank from strings which only consist
of blanks.
Example:
char string[] = " ";
strstrip(string);
results in " ", but should produce an empty string!
The following patch solves this problem:
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by Joern Engel <joern@wh.fh-wedel.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a new strstrip() function to lib/string.c for removing leading and
trailing whitespace from a string.
Cc: Michael Holzheu <holzheu@de.ibm.com>
Acked-by: Ingo Oeser <ioe-lkml@rameria.de>
Acked-by: Joern Engel <joern@wohnheim.fh-wedel.de>
Cc: Corey Minyard <minyard@acm.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Michael Holzheu <HOLZHEU@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some string functions were safely overrideable in lib/string.c, but their
corresponding declarations in linux/string.h were not. Correct this, and
make strcspn overrideable.
Odds of someone wanting to do optimized assembly of these are small, but
for the sake of cleanliness, might as well bring them into line with the
rest of the file.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
While cleaning up parisc_ksyms.c earlier, I noticed that strpbrk wasn't
being exported from lib/string.c. Investigating further, I noticed a
changeset that removed its export and added it to _ksyms.c on a few more
architectures. The justification was that "other arches do it."
I think this is wrong, since no architecture currently defines
__HAVE_ARCH_STRPBRK, there's no reason for any of them to be exporting it
themselves. Therefore, consolidate the export to lib/string.c.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Sam's tree includes a new check, which found that we're exporting strpbrk()
multiple times.
It seems that the convention is that this is exported from the arch files, so
reove the lib/string.c export.
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: David Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A couple of (char *) casts removed in a previous cleanup patch in
lib/string.c:memmove() were actually useful, as they suppressed a couple of
warnings:
assignment discards qualifiers from pointer target type
Fix by declaring the local variable const in the first place, so casts
aren't needed to strip the const qualifier.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The first two hunks of the patch really belongs in patch 1, but I missed
them on the first pass and instead of redoing all 3 patches I stuck them in
this one.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Removes a few pointless register keywords. register is merely a compiler
hint that access to the variable should be optimized, but gcc (3.3.6 in my
case) generates the exact same code with and without the keyword, and even
if gcc did something different with register present I think it is doubtful
we would want to optimize access to these variables - especially since this
is generic library code and there are supposed to be optimized versions in
asm/ for anything that really matters speed wise.
(akpm: iirc, keyword register is a gcc no-op unless using -O0)
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Removes some blank lines, removes some trailing whitespace, adds spaces
after commas and a few similar changes.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
this clarifies the documentation on the behavier of strncpy().
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In include/asm-x86_64/string.h there are such comments:
/* Use C out of line version for memcmp */
#define memcmp __builtin_memcmp
int memcmp(const void * cs,const void * ct,size_t count);
This would mean that if the compiler does not decide to use __builtin_memcmp,
it emits a call to memcmp to be satisfied by the C out-of-line version in
lib/string.c. What happens is that after preprocessing, in lib/string.i you
may find the definition of "__builtin_strcmp".
Actually, by accident, in the object you will find the definition of strcmp
and such (maybe a trick intended to redirect calls to __builtin_memcmp to the
default memcmp when the definition is not expanded); however, this particular
case is not a documented feature as far as I can see.
Also, the EXPORT_SYMBOL does not work, so it's duplicated in the arch.
I simply added some #undef to lib/string.c and removed the (now duplicated)
exports in x86-64 and UML/x86_64 subarchs (the second ones are introduced by
another patch I just posted for -mm).
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Chris Metcalf