In _FORTIFY_SOURCE=3, the size expression may be non-constant,
resulting in branches in the inline functions remaining intact and
causing a tiny overhead. Clang (and in future, gcc) make sure that
the -1 case is always safe, i.e. any comparison of the generated
expression with (size_t)-1 is always false so that bit is taken care
of. The rest is avoidable since we want the _chk variant whenever we
have a size expression and it's not -1.
Rework the conditionals in a uniform way to clearly indicate two
conditions at compile time:
- Either the size is unknown (-1) or we know at compile time that the
operation length is less than the object size. We can call the
original function in this case. It could be that either the length,
object size or both are non-constant, but the compiler, through
range analysis, is able to fold the *comparison* to a constant.
- The size and length are known and the compiler can see at compile
time that operation length > object size. This is valid grounds for
a warning at compile time, followed by emitting the _chk variant.
For everything else, emit the _chk variant.
This simplifies most of the fortified function implementations and at
the same time, ensures that only one call from _chk or the regular
function is emitted.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
Several network-related structures are defined conditionally under
__USE_MISC, but unconditionally used by other headers. The path of
least resistance is usually to condition the uses on __USE_MISC as
well.
* sysdeps/mach/hurd/net/if_ppp.h
* sysdeps/unix/sysv/linux/net/if_ppp.h:
Only define struct ifpppstatsreq and struct ifpppcstatsreq
if __USE_MISC is defined, to ensure struct ifreq is declared.
* inet/netinet/ether.h: Condition all function prototypes
on __USE_MISC, to ensure struct ether_addr is declared.
sys/socket.h defines struct osockaddr only under __USE_MISC, whereas
protocols/talkd.h requires it unconditionally. Here it doesn't make
sense to condition the entire body of protocols/talkd.h on __USE_MISC.
Rather than complicate sys/socket.h with a __need macro or duplicate
the definition, I am introducing a new concept: tiny headers named
bits/types/TYPE.h that define TYPE and nothing else. This can, I hope,
ultimately replace *all* the __need macros. The guard macro for such
headers will be __TYPE_defined, just in case application or third-party
library code is looking at them.
* socket/bits/types/struct_osockaddr.h: New header.
* include/bits/types/struct_osockaddr.h: New wrapper.
* socket/Makefile: Install the new header.
* socket/sys/socket.h, inet/protocols/talkd.h:
Refer to bits/types/struct_osockaddr.h for the definition of
struct osockaddr.
with __warning__/__error__ attributes.
(__warnattr): Define.
* stdlib/bits/stdlib.h (__realpath_chk_warn, __ptsname_r_chk_warn,
__mbstowcs_chk_warn, __wcstombs_chk_warn): New aliases with
__warnattr.
(realpath, ptsname_r, mbstowcs, wcstombs): Call __*_chk_warn instead
of __*_chk if compile time detectable overflow is found.
* libio/bits/stdio2.h (__fgets_chk_warn, __fread_chk_warn,
__fgets_unlocked_chk_warn, __fread_unlocked_chk_warn): New aliases
with __warnattr.
(fgets, fread, fgets_unlocked, fread_unlocked): Call __*_chk_warn
instead of __*_chk if compile time detectable overflow is found.
(__gets_alias): Rename to...
(__gets_warn): ... this. Add __warnattr.
(gets): Call __gets_warn instead of __gets_alias.
* socket/bits/socket2.h (__recv_chk_warn, __recvfrom_chk_warn): New
aliases with __warnattr.
(recv, recvfrom): Call __*_chk_warn instead of __*_chk if compile
time detectable overflow is found.
* posix/bits/unistd.h (__read_chk_warn, __pread_chk_warn,
__pread64_chk_warn, __readlink_chk_warn, __readlinkat_chk_warn,
__getcwd_chk_warn, __confstr_chk_warn, __getgroups_chk_warn,
__ttyname_r_chk_warn, __getlogin_r_chk_warn, __gethostname_chk_warn,
__getdomainname_chk_warn): New aliases with __warnattr.
(read, pread, pread64, readlink, readlinkat, getcwd, confstr,
getgroups, ttyname_r, getlogin_r, gethostname, getdomainname): Call
__*_chk_warn instead of __*_chk if compile time detectable overflow
is found.
(__getgroups_chk): Rename argument to __listlen from listlen.
(__getwd_alias): Rename to...
(__getwd_warn): ... this. Add __warnattr.
(getwd): Call __getwd_warn instead of __getwd_alias.
* wcsmbs/bits/wchar2.h (__wmemcpy_chk_warn, __wmemmove_chk_warn,
__wmempcpy_chk_warn, __wmemset_chk_warn, __wcsncpy_chk_warn,
__wcpncpy_chk_warn, __fgetws_chk_warn, __fgetws_unlocked_chk_warn,
__mbsrtowcs_chk_warn, __wcsrtombs_chk_warn, __mbsnrtowcs_chk_warn,
__wcsnrtombs_chk_warn): New aliases with __warnattr.
(wmemcpy, wmemmove, wmempcpy, wmemset, mbsrtowcs, wcsrtombs,
mbsnrtowcs, wcsnrtombs): Call __*_chk_warn instead of __*_chk if
compile time detectable overflow is found.
(wcsncpy, wcpncpy): Likewise. For constant __n fix check whether
to use __*_chk or not.
(fgetws, fgetws_unlocked): Divide __bos by sizeof (wchar_t), both
in comparisons which function should be called and in __*_chk*
arguments. Call __*_chk_warn instead of __*_chk if compile time
detectable overflow is found.
(swprintf, vswprintf): Divide __bos by sizeof (wchar_t) in
__*_chk argument.
* debug/tst-chk1.c (do_test): Add a few more tests.
map if requested.
* debug/chk_fail.c: Request backtrace and memory map dump.
* Versions.def: Add GLIBC_2.4 for libc.
* debug/fgets_chk.c: New file.
* debug/fgets_u_chk.c: New file.
* debug/getcwd_chk.c: New file.
* debug/getwd_chk.c: New file.
* debug/readlink_chk.c: New file.
* debug/read_chk.c: New file.
* debug/pread_chk.c: New file.
* debug/pread64_chk.c: New file.
* debug/recv_chk.c: New file.
* debug/recvfrom_chk.c: New file.
* debug/Versions: Add all new functions with version GLIBC_2.4.
* debug/Makefile (routines): Add fgets_chk, fgets_u_chk, read_chk,
pread_chk, pread64_chk, recv_chk, recvfrom_chk, readlink_chk,
getwd_chk, and getcwd_chk. Plus appropriate CFLAGS definitions.
* debug/tst-chk1.c: Add more tests.
* libio/bits/stdio2.h: Add macros for fgets and fgets_unlocked.
* include/stdio.h: Declare __fgets_chk and __fgets_unlocked_chk.
* posix/unistd.h: Include <bits/unistd.h> for fortification.
* posix/bits/unistd.h: New file.
* posix/Makefile (headers): Add bits/unistd.h.
* socket/sys/socket.h: Include <bits/socket2.h> for fortification.
* socket/bits/socket2.h: New file.
* socket/Makefile (headers): Add bits/socket2.h.
* string/bits/string3.h: Extend memset macro to check for zero 3rd
parameter and use __memset_zero_constant_len_parameter in that case.
* sysdeps/generic/memset_chk.c: Add
__memset_zero_constant_len_parameter alias and linker warning.
* debug/Versions: Add __memset_zero_constant_len_parameter to libc
with version GLIBC_2.4.
* sysdeps/generic/bits/types.h: Don't unnecessarily use __extension__
in __STD_TYPE definition.
2005-02-21 Jakub Jelinek <jakub@redhat.com>
* malloc/malloc.c (malloc_printerr): If MALLOC_CHECK_={5,7}, print
the error message rather than program name.
2005-02-21 Ulrich Drepper <drepper@redhat.com>
