From af130d27099651e0d27b2cf2cfb44dafd6fe8a26 Mon Sep 17 00:00:00 2001 From: Andreas Schwab Date: Tue, 30 Jan 2018 10:16:00 +0100 Subject: Always do locking when accessing streams (bug 15142, bug 14697) 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. --- libio/genops.c | 43 ++++++++++--------------------------------- libio/libioP.h | 1 - 2 files changed, 10 insertions(+), 34 deletions(-) (limited to 'libio') diff --git a/libio/genops.c b/libio/genops.c index 7131312704..fbd8dd9e75 100644 --- a/libio/genops.c +++ b/libio/genops.c @@ -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. diff --git a/libio/libioP.h b/libio/libioP.h index d777553cb0..745278e076 100644 --- a/libio/libioP.h +++ b/libio/libioP.h @@ -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); -- cgit 1.4.1