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Always do locking when accessing streams (bug 15142, bug 14697)

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Now that abort no longer calls fflush there is no reason to avoid locking
the stdio streams anywhere.  This fixes a conformance issue and potential
heap corruption during exit.
This commit is contained in:
Andreas Schwab 2018-01-30 10:16:00 +01:00
parent 27cb2bb93d
commit af130d2709
2 changed files with 10 additions and 34 deletions
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43
libio/genops.c
View File

@ -682,7 +682,7 @@ _IO_adjust_column (unsigned start, const char *line, int count)
libc_hidden_def (_IO_adjust_column)
int
_IO_flush_all_lockp (int do_lock)
_IO_flush_all (void)
{
int result = 0;
FILE *fp;
@ -695,8 +695,7 @@ _IO_flush_all_lockp (int do_lock)
for (fp = (FILE *) _IO_list_all; fp != NULL; fp = fp->_chain)
{
run_fp = fp;
if (do_lock)
_IO_flockfile (fp);
_IO_flockfile (fp);
if (((fp->_mode <= 0 && fp->_IO_write_ptr > fp->_IO_write_base)
|| (_IO_vtable_offset (fp) == 0
@ -706,8 +705,7 @@ _IO_flush_all_lockp (int do_lock)
&& _IO_OVERFLOW (fp, EOF) == EOF)
result = EOF;
if (do_lock)
_IO_funlockfile (fp);
_IO_funlockfile (fp);
run_fp = NULL;
}
@ -718,14 +716,6 @@ _IO_flush_all_lockp (int do_lock)
return result;
}
int
_IO_flush_all (void)
{
/* We want locking. */
return _IO_flush_all_lockp (1);
}
libc_hidden_def (_IO_flush_all)
void
@ -791,6 +781,9 @@ _IO_unbuffer_all (void)
{
int legacy = 0;
run_fp = fp;
_IO_flockfile (fp);
#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
if (__glibc_unlikely (_IO_vtable_offset (fp) != 0))
legacy = 1;
@ -800,18 +793,6 @@ _IO_unbuffer_all (void)
/* Iff stream is un-orientated, it wasn't used. */
&& (legacy || fp->_mode != 0))
{
#ifdef _IO_MTSAFE_IO
int cnt;
#define MAXTRIES 2
for (cnt = 0; cnt < MAXTRIES; ++cnt)
if (fp->_lock == NULL || _IO_lock_trylock (*fp->_lock) == 0)
break;
else
/* Give the other thread time to finish up its use of the
stream. */
__sched_yield ();
#endif
if (! legacy && ! dealloc_buffers && !(fp->_flags & _IO_USER_BUF))
{
fp->_flags |= _IO_USER_BUF;
@ -825,17 +806,15 @@ _IO_unbuffer_all (void)
if (! legacy && fp->_mode > 0)
_IO_wsetb (fp, NULL, NULL, 0);
#ifdef _IO_MTSAFE_IO
if (cnt < MAXTRIES && fp->_lock != NULL)
_IO_lock_unlock (*fp->_lock);
#endif
}
/* Make sure that never again the wide char functions can be
used. */
if (! legacy)
fp->_mode = -1;
_IO_funlockfile (fp);
run_fp = NULL;
}
#ifdef _IO_MTSAFE_IO
@ -861,9 +840,7 @@ __libio_freemem (void)
int
_IO_cleanup (void)
{
/* We do *not* want locking. Some threads might use streams but
that is their problem, we flush them underneath them. */
int result = _IO_flush_all_lockp (0);
int result = _IO_flush_all ();
/* We currently don't have a reliable mechanism for making sure that
C++ static destructors are executed in the correct order.

1
libio/libioP.h
View File

@ -537,7 +537,6 @@ extern int _IO_new_do_write (FILE *, const char *, size_t);
extern int _IO_old_do_write (FILE *, const char *, size_t);
extern int _IO_wdo_write (FILE *, const wchar_t *, size_t);
libc_hidden_proto (_IO_wdo_write)
extern int _IO_flush_all_lockp (int);
extern int _IO_flush_all (void);
libc_hidden_proto (_IO_flush_all)
extern void _IO_flush_all_linebuffered (void);