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Author SHA1 Message Date
Zack Weinberg
03992356e6
Use C99-compliant scanf under _GNU_SOURCE with modern compilers. 
The only difference between noncompliant and C99-compliant scanf is
that the former accepts the archaic GNU extension '%as' (also %aS and
%a[...]) meaning to allocate space for the input string with malloc.
This extension conflicts with C99's use of %a as a format _type_
meaning to read a floating-point number; POSIX.1-2008 standardized
equivalent functionality using the modifier letter 'm' instead (%ms,
%mS, %m[...]).

The extension was already disabled in most conformance modes:
specifically, any mode that doesn't involve _GNU_SOURCE and _does_
involve either strict conformance to C99 or loose conformance to both
C99 and POSIX.1-2001 would get the C99-compliant scanf.  With
compilers new enough to use -std=gnu11 instead of -std=gnu89, or
equivalent, that includes the default mode.

With this patch, we now provide C99-compliant scanf in all
configurations except when _GNU_SOURCE is defined *and*
__STDC_VERSION__ or __cplusplus (whichever is relevant) indicates
C89/C++98.  This leaves the old scanf available under e.g. -std=c89
-D_GNU_SOURCE, but removes it from e.g. -std=gnu11 -D_GNU_SOURCE (it
was already not present under -std=gnu11 without -D_GNU_SOURCE) and
from -std=gnu89 without -D_GNU_SOURCE.

There needs to be an internal override so we can compile the
noncompliant scanf itself.  This is the same problem we had when we
removed 'gets' from _GNU_SOURCE and it's dealt with the same way:
there's a new __GLIBC_USE symbol, DEPRECATED_SCANF, which defaults to
off under the appropriate conditions for external code, but can be
overridden by individual files within stdio.

We also run into problems with PLT bypass for internal uses of sscanf,
because libc_hidden_proto uses __REDIRECT and so does the logic in
stdio.h for choosing which implementation of scanf to use; __REDIRECT
isn't transitive, so include/stdio.h needs to bridge the gap with a
macro.  As far as I can tell, sscanf is the only function in this
family that's internally called by unrelated code.

Finally, there are several tests in stdio-common that use the
extension.  bug21.c is a regression test for a crash; it still
exercises the relevant code when changed to use %ms instead of %as.
scanf14.c through scanf17.c are more complicated since they are
actually testing the subtleties of the extension - under what
circumstances is 'a' treated as a modifier letter, etc.  I changed all
of them to use %ms instead of %as as well, but duplicated scanf14.c
and scanf16.c as scanf14a.c and scanf16a.c.  These still use %as and
are compiled with -std=gnu89 to access the old extension.  A bunch of
diagnostic overrides and manual workarounds for the old stdio.h
behavior become unnecessary.  Yay!

	* include/features.h (__GLIBC_USE_DEPRECATED_SCANF): New __GLIBC_USE
	parameter.  Only use deprecated scanf when __USE_GNU is defined
	and __STDC_VERSION__ is less than 199901L or __cplusplus is less
	than 201103L, whichever is relevant for the language being compiled.

	* libio/stdio.h, libio/bits/stdio-ldbl.h: Decide whether to redirect
	scanf, fscanf, sscanf, vscanf, vfscanf, and vsscanf to their
	__isoc99_ variants based only on __GLIBC_USE (DEPRECATED_SCANF).
	* wcsmbs/wchar.h: wcsmbs/bits/wchar-ldbl.h: Likewise for
	wscanf, fwscanf, swscanf, vwscanf, vfwscanf, and vswscanf.

	* libio/iovsscanf.c
	* libio/fwscanf.c
	* libio/iovswscanf.c
	* libio/swscanf.c
	* libio/vscanf.c
	* libio/vwscanf.c
	* libio/wscanf.c
	* stdio-common/fscanf.c
	* stdio-common/scanf.c
	* stdio-common/vfscanf.c
	* stdio-common/vfwscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-compat.c
	* sysdeps/ieee754/ldbl-opt/nldbl-fscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-fwscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-iovfscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-scanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-sscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-swscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-vfscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-vfwscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-vscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-vsscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-vswscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-vwscanf.c
	* sysdeps/ieee754/ldbl-opt/nldbl-wscanf.c:
	Override __GLIBC_USE_DEPRECATED_SCANF to 1.

	* stdio-common/sscanf.c: Likewise.  Remove ldbl_hidden_def for __sscanf.
	* stdio-common/isoc99_sscanf.c: Add libc_hidden_def for __isoc99_sscanf.
	* include/stdio.h: Provide libc_hidden_proto for __isoc99_sscanf,
	not sscanf.
	[!__GLIBC_USE (DEPRECATED_SCANF)]: Define sscanf as __isoc99_scanf
	with a preprocessor macro.

	* stdio-common/bug21.c, stdio-common/scanf14.c:
	Use %ms instead of %as, %mS instead of %aS, %m[] instead of %a[];
	remove DIAG_IGNORE_NEEDS_COMMENT for -Wformat.
	* stdio-common/scanf16.c: Likewise.  Add __attribute__ ((format (scanf)))
	to xscanf, xfscanf, xsscanf.

	* stdio-common/scanf14a.c: New copy of scanf14.c which still uses
	%as, %aS, %a[].  Remove DIAG_IGNORE_NEEDS_COMMENT for -Wformat.
	* stdio-common/scanf16a.c: New copy of scanf16.c which still uses
	%as, %aS, %a[].  Add __attribute__ ((format (scanf))) to xscanf,
	xfscanf, xsscanf.
	* stdio-common/scanf15.c, stdio-common/scanf17.c: No need to
	override feature selection macros or provide definitions of u_char etc.
	* stdio-common/Makefile (tests): Add scanf14a and scanf16a.
	(CFLAGS-scanf15.c, CFLAGS-scanf17.c): Remove.
	(CFLAGS-scanf14a.c, CFLAGS-scanf16a.c): New.  Compile these files
	with -std=gnu89.
 2019-01-03 11:12:39 -05:00
Zack Weinberg
e15f7de60c Split DIAG_* macros to new header libc-diag.h. 
Quite a few tests include libc-internal.h just for the DIAG_* macros.
Split those macros to their own file, which can be included safely in
_ISOMAC mode.  I also moved ignore_value, since it seems logically
related, even though I didn't notice any tests needing it.

Also add -Wnonnull suppressions to two tests that _should_ have them,
but the error is masked when compiling against internal headers.

	* include/libc-diag.h: New file.  Define ignore_value,
	DIAG_PUSH_NEEDS_COMMENT, DIAG_POP_NEEDS_COMMENT,
	DIAG_IGNORE_NEEDS_COMMENT, and DIAG_IGNORE_Os_NEEDS_COMMENT here.

	* include/libc-internal.h: Definitions of above macros moved from
	here.  Include libc-diag.h.  Add copyright notice.

	* malloc/tst-malloc.c, malloc/tst-memcheck.c, malloc/tst-realloc.c
	* misc/tst-error1.c, posix/tst-dir.c, stdio-common/bug21.c
	* stdio-common/scanf14.c, stdio-common/scanf4.c, stdio-common/scanf7.c
	* stdio-common/test-vfprintf.c, stdio-common/tst-printf.c
	* stdio-common/tst-printfsz.c, stdio-common/tst-sprintf.c
	* stdio-common/tst-unlockedio.c, stdio-common/tstdiomisc.c
	* stdlib/bug-getcontext.c, string/tester.c, string/tst-endian.c
	* time/tst-strptime2.c, wcsmbs/tst-wcstof.c:
	Include libc-diag.h instead of libc-internal.h.

	* stdlib/tst-environ.c: Include libc-diag.h.  Suppress -Wnonnull for
	call to unsetenv (NULL).
	* nptl/tst-mutex1.c: Include libc-diag.h.  Suppress -Wnonnull for
	call to pthread_mutexattr_destroy (NULL).
 2017-02-25 09:59:46 -05:00
Joseph Myers
2084e7ca4d Add macros for diagnostic control, use for scanf %a tests. 
In <https://sourceware.org/ml/libc-alpha/2014-11/msg00326.html>,
Roland requested internal macros for use of "#pragma GCC diagnostic".

This patch adds such macros and uses them to disable -Wformat warnings
for some code testing GNU scanf %as where GCC expects C99 scanf %a
(several other stdio tests currently use -Wno-format to disable
warnings).  Limitations in GCC's diagnostic pragmas require separate
macros before and after the code generating the warnings, rather than
a single macro taking that code as an argument.

The macros are named DIAG_*_NEEDS_COMMENT to emphasise to reviewers
the need for a comment accompanying any use of them (such comments may
however just appear once for several uses of the macros for the same
issue in the same file).  I put a GCC version in the arguments to
DIAG_IGNORE_NEEDS_COMMENT, as that seems something useful to grep for
when obsoleting support for an old GCC version and needing to decide
if warning-disabling code is still relevant.

These macros should be usable for replacing existing -Wno-* use in
makefiles (as also suggested by Roland), though I have no plans to
work on that (only on use of the macros in cases where warnings are
currently present that need disabling to use -Werror).

Tested for x86_64.

	* include/libc-internal.h (DIAG_PUSH_NEEDS_COMMENT): New macro.
	(DIAG_POP_NEEDS_COMMENT): Likewise.
	(_DIAG_STR1): Likewise.
	(_DIAG_STR): Likewise.
	(DIAG_IGNORE_NEEDS_COMMENT): Likewise.
	* stdio-common/bug21.c: Include <libc-internal.h>.
	(do_test): Disable -Wformat around call to sscanf.
	* stdio-common/scanf14.c: Include <libc-internal.h>.
	(main): Disable -Wformat around some calls to scanf functions.
 2014-12-10 00:41:19 +00:00
Jakub Jelinek
ad8a551196 * libio/stdio.h (vscanf): Fix -std=c99 redirect. 
* stdio-common/Makefile (tests): Add scanf16 and scanf17. 
(CFLAGS-scanf17.c): New. 
* stdio-common/scanf14.c (main): Add fscanf and scanf tests. 
* stdio-common/scanf15.c (main): Likewise. 
* stdio-common/scanf16.c: New test. 
* stdio-common/scanf17.c: New test.
2008-05-24  Jakub Jelinek  <jakub@redhat.com>

	* libio/stdio.h (vscanf): Fix -std=c99 redirect.
	* stdio-common/Makefile (tests): Add scanf16 and scanf17.
	(CFLAGS-scanf17.c): New.
	* stdio-common/scanf14.c (main): Add fscanf and scanf tests.
	* stdio-common/scanf15.c (main): Likewise.
	* stdio-common/scanf16.c: New test.
	* stdio-common/scanf17.c: New test.
 2008-05-24 18:14:36 +00:00
Ulrich Drepper
874aa52349 * include/stdio.h (__isoc99_fscanf, __isoc99_scanf, 
__isoc99_sscanf, __isoc99_vscanf): New prototypes.
	(__isoc99_vsscanf, __isoc99_vfscanf): New prototypes, add
	libc_hidden_proto.
	* include/wchar.h (__isoc99_fwscanf, __isoc99_wscanf,
	__isoc99_swscanf, __isoc99_vwscanf): New prototypes.
	(__isoc99_vswscanf, __isoc99_vfwscanf): New prototypes,
	add libc_hidden_proto.
	* libio/stdio.h (fscanf, scanf, sscanf, vfscanf, vscanf,
	vsscanf): Redirect to __isoc99_* if strict ISO C99 or POSIX
	conformance requested.
	* wcsmbs/wchar.h (fwscanf, wscanf, swscanf, vfwscanf, vwscanf,
	vswscanf): Redirect to __isoc99_* if strict ISO C99 or POSIX
	conformance requested.
	* libio/bits/stdio-ldbl.h (fscanf, scanf, sscanf, vfscanf, vscanf,
	vsscanf): Redirect to __nldbl___isoc99_* if strict ISO C99 or POSIX
	conformance requested.
	* wcsmbs/bits/wchar-ldbl.h (fwscanf, wscanf, swscanf, vfwscanf,
	vwscanf, vswscanf): Redirect to __nldbl___isoc99_* if strict
	ISO C99 or POSIX conformance requested.
	* stdio-common/Versions (libc): Export __isoc99_scanf@@GLIBC_2.7,
	__isoc99_vscanf@@GLIBC_2.7, __isoc99_fscanf@@GLIBC_2.7,
	__isoc99_vfscanf@@GLIBC_2.7, __isoc99_sscanf@@GLIBC_2.7
	and __isoc99_vsscanf@@GLIBC_2.7.
	* stdio-common/Makefile (routines): Add isoc99_scanf, isoc99_vscanf,
	isoc99_fscanf, isoc99_vfscanf, isoc99_sscanf and isoc99_vsscanf.
	(tests): Add scanf14.
	(CFLAGS-vfprintf.c, CFLAGS-fprintf.c, CFLAGS-printf.c,
	CFLAGS-vfwprintf.c, CFLAGS-vfscanf.c, CFLAGS-vfwscanf.c,
	CFLAGS-fscanf.c, CFLAGS-scanf.c, CFLAGS-isoc99_vfscanf.c,
	CFLAGS-isoc99_vscanf.c, CFLAGS-isoc99_fscanf.c,
	CFLAGS-isoc99_scanf.c): Add $(exceptions).
	(CFLAGS-scanf15.c): Add various -I paths to prevent the compiler
	from using internal headers.
	* wcsmbs/Versions (libc): Export __isoc99_wscanf@@GLIBC_2.7,
	__isoc99_vwscanf@@GLIBC_2.7, __isoc99_fwscanf@@GLIBC_2.7,
	__isoc99_vfwscanf@@GLIBC_2.7, __isoc99_swscanf@@GLIBC_2.7
	and __isoc99_vswscanf@@GLIBC_2.7.
	* wcsmbs/Makefile (routines): Add isoc99_wscanf, isoc99_vwscanf,
	isoc99_fwscanf, isoc99_vfwscanf, isoc99_swscanf and isoc99_vswscanf.
	(CFLAGS-isoc99_wscanf.c, CFLAGS-isoc99_fwscanf.c,
	CFLAGS-isoc99_vwscanf.c, CFLAGS-isoc99_vfwscanf.c): Add $(exceptions).
	(CPPFLAGS): Add -D_IO_MTSAFE_IO if needed.
	* stdio-common/isoc99_scanf.c: New file.
	* stdio-common/isoc99_vsscanf.c: New file.
	* stdio-common/isoc99_vscanf.c: New file.
	* stdio-common/isoc99_vfscanf.c: New file.
	* stdio-common/isoc99_fscanf.c: New file.
	* stdio-common/isoc99_sscanf.c: New file.
	* wcsmbs/isoc99_fwscanf.c: New file.
	* wcsmbs/isoc99_vswscanf.c: New file.
	* wcsmbs/isoc99_swscanf.c: New file.
	* wcsmbs/isoc99_wscanf.c: New file.
	* wcsmbs/isoc99_vwscanf.c: New file.
	* wcsmbs/isoc99_vfwscanf.c: New file.
	* libio/libio.h (_IO_FLAGS2_SCANF_STD): Define.
	* libio/libioP.h (_IO_acquire_lock_clear_flags2_fct): Also
	clear _IO_FLAGS2_SCANF_STD bit from _flags2.
	* stdio-common/vfscanf.c (_IO_vfscanf_internal): Don't
	handle %as, %aS and %a[ if _IO_FLAGS2_SCANF_STD is set in _flags2.
	* stdio-common/scanf14.c: New test.
	* stdio-common/scanf15.c: New test.
	* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add
	isoc99_scanf, isoc99_fscanf, isoc99_sscanf,
	isoc99_vscanf, isoc99_vfscanf, isoc99_vsscanf,
	isoc99_wscanf, isoc99_fwscanf, isoc99_swscanf,
	isoc99_vwscanf, isoc99_vfwscanf and isoc99_vswscanf.
	* sysdeps/ieee754/ldbl-opt/Versions (libc): Export
	__nldbl___isoc99_scanf@@GLIBC_2.7,
	__nldbl___isoc99_fscanf@@GLIBC_2.7,
	__nldbl___isoc99_sscanf@@GLIBC_2.7,
	__nldbl___isoc99_vscanf@@GLIBC_2.7,
	__nldbl___isoc99_vfscanf@@GLIBC_2.7,
	__nldbl___isoc99_vsscanf@@GLIBC_2.7,
	__nldbl___isoc99_wscanf@@GLIBC_2.7,
	__nldbl___isoc99_fwscanf@@GLIBC_2.7,
	__nldbl___isoc99_swscanf@@GLIBC_2.7,
	__nldbl___isoc99_vwscanf@@GLIBC_2.7,
	__nldbl___isoc99_vfwscanf@@GLIBC_2.7
	and __nldbl___isoc99_vswscanf@@GLIBC_2.7.
	* sysdeps/ieee754/ldbl-opt/nldbl-compat.h (__isoc99_scanf,
	__isoc99_fscanf, __isoc99_sscanf, __isoc99_vscanf,
	__isoc99_vfscanf, __isoc99_vsscanf, __isoc99_wscanf,
	__isoc99_fwscanf, __isoc99_swscanf, __isoc99_vwscanf,
	__isoc99_vfwscanf, __isoc99_vswscanf): Add NLDBL_DECL.
	* sysdeps/ieee754/ldbl-opt/nldbl-compat.c
	(__nldbl___isoc99_scanf, __nldbl___isoc99_fscanf,
	__nldbl___isoc99_sscanf, __nldbl___isoc99_vscanf,
	__nldbl___isoc99_vfscanf, __nldbl___isoc99_vsscanf,
	__nldbl___isoc99_wscanf, __nldbl___isoc99_fwscanf,
	__nldbl___isoc99_swscanf, __nldbl___isoc99_vwscanf,
	__nldbl___isoc99_vfwscanf, __nldbl___isoc99_vswscanf): New
	functions.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_vfscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_swscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_vwscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_wscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_scanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_sscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_vsscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_fwscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_vfwscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_vswscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_vscanf.c: New file.
	* sysdeps/ieee754/ldbl-opt/nldbl-isoc99_fscanf.c: New file.

	* stdio-common/Makefile (tests): Add scanf13.
	(scanf13-ENV): New.
	* stdio-common/vfscanf.c (_IO_vfscanf_internal): Handle
	m modifier followed by l.
	(STRING_ARG): Add width argument.
	(_IO_vfscanf_internal) <case L_('c')>: Handle %mc.
	<case L_('C')>: Handle %mlc and %mC.
	<case L_('s'), case L_('S'), case L_('[')>: Adjust STRING_ARG
	arguments.
	* stdio-common/scanf13.c: New test.

	* libio/libioP.h (_IO_acquire_lock_clear_flags2_fct): Clear
	the _IO_FLAGS2_FORTIFY bit from _flags2 rather than _flags.

	type and __THROW marker of splice, vmsplice, and tee.
 2007-09-18 19:04:01 +00:00