Commit graph

22 commits

Author SHA1 Message Date
Rasmus Villemoes
fb63362c63 lib: fix buggy strcmp and strncmp
There are two problems with both strcmp and strncmp:

(1) The C standard is clear that the contents should be compared as
"unsigned char":

  The sign of a nonzero value returned by the comparison functions
  memcmp, strcmp, and strncmp is determined by the sign of the
  difference between the values of the first pair of characters (both
  interpreted as unsigned char) that differ in the objects being
  compared.

(2) The difference between two char (or unsigned char) values can
range from -255 to +255; so that's (due to integer promotion) the
range of values we could get in the *cs-*ct expressions, but when that
is then shoe-horned into an 8-bit quantity the sign may of course
change.

The impact is somewhat limited by the way these functions
are used in practice:

- Most of the time, one is only interested in equality (or for
  strncmp, "starts with"), and the existing functions do correctly
  return 0 if and only if the strings are equal [for strncmp, up to
  the given bound].

- Also most of the time, the strings being compared only consist of
  ASCII characters, i.e. have values in the range [0, 127], and in
  that case it doesn't matter if they are interpreted as signed or
  unsigned char, and the possible difference range is bounded to
  [-127, 127] which does fit the signed char.

For size, one could implement strcmp() in terms of strncmp() - just
make it "return strncmp(a, b, (size_t)-1);". However, performance of
strcmp() does matter somewhat, since it is used all over when parsing
and matching DT nodes and properties, so let's find some other place
to save those ~30 bytes.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
2022-10-27 09:10:08 -04:00
Simon Glass
930c887e0f lib: Add memdup()
Add a function to duplicate a memory region, a little like strdup().

Signed-off-by: Simon Glass <sjg@chromium.org>
2021-10-08 15:53:26 -04:00
Marek Behún
46c3e29219 string: make memcpy(), memset(), memcmp() and memmove() visible for LTO
It seems that sometimes (happening on ARM64, for example with
turris_mox_defconfig) GCC, when linking with LTO, changes the symbol
names of some functions, for example lib/string.c's memcpy() function to
memcpy.isra.0.

This is a problem however when GCC for a code such as this:
	struct some_struct *info = get_some_struct();
	struct some struct tmpinfo;
	tmpinfo = *info;
emits a call to memcpy() by builtin behaviour, to copy *info to tmpinfo.

This then results in the following linking error:
  .../lz4.c:93: undefined reference to `memcpy'
  .../uuid.c:206: more undefined references to `memcpy' follow

GCC's documentation says this about -nodefaultlibs option:
  The compiler may generate calls to "memcmp", "memset", "memcpy" and
  "memmove".  These entries are usually resolved by entries in libc.
  These entry points should be supplied through some other mechanism
  when this option is specified.

Make these functions visible by using the __used macro to avoid this
error.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>
2021-05-24 14:21:30 -04:00
Sean Anderson
9af869c414 lib: string: Implement strlcat
This introduces strlcat, which provides a safer interface than strncat. It
never copies more than its size bytes, including the terminating nul. In
addition, it never reads past dest[size - 1], even if dest is not
nul-terminated.

This also removes the stub for dwc3 now that we have a proper
implementation.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2021-04-12 17:44:55 -04:00
Sean Anderson
d3358ecc54 lib: string: Fix strlcpy return value
strlcpy should always return the number of bytes copied. We were
accidentally missing the nul-terminator. We also always used to return a
non-zero value, even if we did not actually copy anything.

Fixes: 23cd138503 ("Integrate USB gadget layer and USB CDC driver layer")

Signed-off-by: Sean Anderson <seanga2@gmail.com>
2021-04-12 17:44:55 -04:00
Patrick Delaunay
976a68a20d string: Use memcpy() within memmove() when we can
A common use of memmove() can be handled by memcpy(). Also memcpy()
includes an optimization for large sizes: it copies a word at a time. So
we can get a speed-up by calling memcpy() to handle our move in this case.

Update memmove() to call also memcpy() if the source don't overlap
the destination (src + count <= dest).

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
2021-01-16 14:49:09 -05:00
Simon Glass
1ea1c7d80f string: Allow arch override of strndup() also
At present architectures can override strdup() but not strndup(). Use
the same option for both.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-02-05 19:33:46 -07:00
Thierry Reding
0c4e2658e8 lib: Implement strndup()
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
2019-06-05 09:16:32 -07:00
Simon Glass
96794a3eae string: Include the config header
At present the config header is not included in this file, but it does use
a CONFIG option. Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>
2018-11-20 19:14:22 -07:00
Simon Glass
a7d0021063 string: Add strcspn()
Add an implementation of strcspn() which returns the number of initial
characters that do not match any in a rejection list.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:12 -06:00
Simon Glass
6b45ba45fb string: Add strchrnul()
This functions works like strchr() but returns the end of the string if
the character is not found. Add an implementation of this.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:12 -06:00
Simon Glass
cb0eae8cf8 string: Use memcpy() within memmove() when we can
A common use of memmove() can be handled by memcpy(). Also memcpy()
includes an optimisation for large sizes: it copies a word at a time. So
we can get a speed-up by calling memcpy() to handle our move in this case.

Update memmove() to call memcpy() if the destination is before the source.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
2017-05-09 20:19:04 -04:00
Simon Glass
ab4458bdb5 string: Provide a slimmed-down memset()
Most of the time the optimised memset() is what we want. For extreme
situations such as TPL it may be too large. For example on the 'rock'
board, using a simple loop saves a useful 48 bytes. With gcc 4.9 and
the rodata bug, this patch is enough to reduce the TPL image below the
limit.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
2017-04-04 20:01:57 -06:00
Robert P. J. Day
25bab53ab2 Remove unneeded remnants of bcopy().
Since bcopy() is no longer used, delete all remaining references to
it.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
2016-06-06 13:39:18 -04:00
Masahiro Yamada
80d9ef8d40 lib: string: move strlcpy() to a common place
Move strlcpy() definition from drivers/usb/gadget/ether.c to
lib/string.c because it is a very useful function.
Let's add the prototype to include/linux/string.h too.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
2014-12-11 13:18:41 -07:00
Wolfgang Denk
d4c8aa9cb4 Coding Style cleanup: remove trailing empty lines
Signed-off-by: Wolfgang Denk <wd@denx.de>
2013-10-14 16:06:54 -04:00
Sergey Lapin
dfe64e2c89 mtd: resync with Linux-3.7.1
This patch is essentially an update of u-boot MTD subsystem to
the state of Linux-3.7.1 with exclusion of some bits:

- the update is concentrated on NAND, no onenand or CFI/NOR/SPI
flashes interfaces are updated EXCEPT for API changes.

- new large NAND chips support is there, though some updates
have got in Linux-3.8.-rc1, (which will follow on top of this patch).

To produce this update I used tag v3.7.1 of linux-stable repository.

The update was made using application of relevant patches,
with changes relevant to U-Boot-only stuff sticked together
to keep bisectability. Then all changes were grouped together
to this patch.

Signed-off-by: Sergey Lapin <slapin@ossfans.org>
[scottwood@freescale.com: some eccstrength and build fixes]
Signed-off-by: Scott Wood <scottwood@freescale.com>
2013-05-31 17:12:03 -05:00
Joe Hershberger
e772cb30f6 Make linux kernel string funcs available to tools
isspace() and strim() are not in the typical user-mode string.h, so
put them in a separate compilation unit so that they can be built into
tools that need them independent of the other common string functions.

This allows code shared by u-boot and the linux user-mode tools to link.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
2012-12-13 11:46:07 -07:00
Simon Glass
b1f17bf5ff Add strcasecmp() and strncasecmp()
strncasecmp() is present as strnicmp() but disabled. Make it available
and define strcasecmp() also. There is a only a small performance penalty
to having strcasecmp() call strncasecmp(), so do this instead of a
standalone function, to save code space.

Update the prototype in arch-specific headers as needed to avoid warnings.

Signed-off-by: Simon Glass <sjg@chromium.org>
2012-12-11 13:17:34 -07:00
Christian Hitz
5454ddbc9b nand: Sanitize ONFI strings.
[backport from linux commit 02f8c6aee8df3cdc935e9bdd4f2d020306035dbe]

This is part of the synchronization with the nand driver to the
Linux 3.0 state.

Signed-off-by: Christian Hitz <christian.hitz@aizo.com>
Cc: Scott Wood <scottwood@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
2012-01-26 16:09:02 -06:00
Matthias Weisser
b038db852b memcpy/memmove: Do not copy to same address
In some cases (e.g. bootm with a elf payload which is already at the right
position) there is a in place copy of data to the same address. Catching this
saves some ms while booting.

Signed-off-by: Matthias Weisser <weisserm@arcor.de>
2011-07-26 00:28:44 +02:00
Peter Tyser
78acc472d9 Rename lib_generic/ to lib/
Now that the other architecture-specific lib directories have been
moved out of the top-level directory there's not much reason to have the
'_generic' suffix on the common lib directory.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
2010-04-13 09:13:04 +02:00
Renamed from lib_generic/string.c (Browse further)