When ungetc is called on an unused stream, the backup buffer is
allocated without the main get area being present. This results in
every subsequent ungetc (as the stream remains in the backup area)
checking uninitialized memory in the backup buffer when trying to put a
character back into the stream.
Avoid comparing the input character with buffer contents when in backup
to avoid this uninitialized read. The uninitialized read is harmless in
this context since the location is promptly overwritten with the input
character, thus fulfilling ungetc functionality.
Also adjust wording in the manual to drop the paragraph that says glibc
cannot do multiple ungetc back to back since with this change, ungetc
can actually do this.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Various glibc testcases use tmpnam in ways subject to race conditions
(generate a temporary file name, then later open that file without
O_EXCL).
This patch fixes those tests to use mkstemp - generally a minimal
local fix to use mkstemp instead of tmpnam, rather than a larger fix
to use other testsuite infrastructure for temporary files. The
unchanged use of tmpnam in posix/wordexp-test.c would fail safe in the
event of a race (it's generating a name for use with mkdir rather than
for a file to be opened for writing).
Tested for x86_64.
* grp/tst_fgetgrent.c: Include <unistd.h>.
(main): Use mkstemp instead of tmpnam.
* io/test-utime.c (main): Likewise.
* posix/annexc.c (macrofile): Change to modifiable array.
(get_null_defines): Use mkstemp instead of tmpnam. Do not remove
macrofile here.
* posix/bug-getopt1.c: Include <stdlib.h>.
(do_test): Use mkstemp instead of tmpnam.
* posix/bug-getopt2.c: Include <stdlib.h>.
(do_test): Use mkstemp instead of tmpnam.
* posix/bug-getopt3.c: Include <stdlib.h>.
(do_test): Use mkstemp instead of tmpnam.
* posix/bug-getopt4.c: Include <stdlib.h>.
(do_test): Use mkstemp instead of tmpnam.
* posix/bug-getopt5.c: Include <stdlib.h>.
(do_test): Use mkstemp instead of tmpnam.
* stdio-common/bug7.c: Include <stdlib.h> and <unistd.h>.
(main): Use mkstemp instead of tmpnam.
* stdio-common/tst-fdopen.c: Include <stdlib.h>.
(main): Use mkstemp instead of tmpnam.
* stdio-common/tst-ungetc.c: Include <stdlib.h>.
(main): use mkstemp instead of tmpnam.
* stdlib/isomac.c (macrofile): Change to modifiable array.
(get_null_defines): Use mkstemp instead of tmpnam. Do not remove
macrofile here.
2002-02-25 Jakub Jelinek <jakub@redhat.com>
* libio/iofopen.c (__fopen_maybe_mmap): Set the initial
position to fp->_offset if it is set.
* stdio-common/Makefile (tests): Add tst-fdopen.
* stdio-common/tst-fdopen.c: New test.
2002-02-25 Jakub Jelinek <jakub@redhat.com>
* libio/fileops.c (_IO_file_xsgetn_mmap): Handle reading from backup.
* stdio-common/tst-ungetc.c (main): Add another test.
* sysdeps/sparc/jmp_buf.h: Rewritten; use array of ints, not struct.
* sysdeps/sparc/setjmp.S: Rewritten; store %fp value as well.
* sysdeps/sparc/__longjmp.S: Rewritten; unwind frames one by one with
`restore' until the target frame is hit.
Sun Mar 10 20:29:40 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
* sysdeps/unix/sysv/linux/sigsuspend.c: New file.
* sysdeps/unix/sysv/linux/syscalls.list: Remove sigsuspend, add
s_sigsuspend.
Thu Mar 7 21:30:58 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
* Makerules (+make-deps, sed-remove-objpfx): Quote periods on the
left side of sed substitutions.
Sun Mar 10 16:58:10 1996 Ulrich Drepper <drepper@gnu.ai.mit.edu>
* stdio-common/printf_fp.c (hack_digit): __mpn_normal_size
is not available anymore. Do it ourselves.
* sysdeps/unix/sysv/linux/i386/fpu_control.h (_FPU_SETCW):
Correct GCC `asm' syntax.
* stdio-common/Makefile (tests): Add tst-ungetc.
* stdio-common/tst-ungetc.c: New test from drepper.
* stdio-common/tstscanf.c (main): New %[ test case from drepper.
* sysdeps/libm-ieee754/s_scalbn.c (scalbn): Rename to __scalbn;
somehow this was missed, though the weak alias is already there.
