PING On Sun, May 8, 2011 at 19:53, Janne Blomqvist <blomqvist.ja...@gmail.com> wrote: > On Sun, May 8, 2011 at 14:40, Janne Blomqvist <blomqvist.ja...@gmail.com> > wrote: >> On Sat, May 7, 2011 at 19:35, Janne Blomqvist <blomqvist.ja...@gmail.com> >> wrote: >>> Hi, >>> >>> the error printing functionality (in io/unix.c) st_printf and >>> st_vprintf are not thread-safe as they use a static buffer. However, >>> since these routines are used when something has gone wrong, we >>> shouldn't use malloc() to allocate thread-specific buffers or anything >>> fancy like that. The way the buffer is used is that it is filled with >>> vs(n)printf() and then the buffer is written using write(); the >>> simplest way to fix this is to just print directly using vfprintf(), >>> which is what this patch does. Also, the patch uses >>> flockfile/funlockfile in a few places to increase the likelihood of >>> multiple related messages to end up together on the output. >>> >>> As stderr is unbuffered and stdout is buffered, this patch also gets >>> rid of the functionality to choose where to send the error output, as >>> we don't want to deal with buffering in the error handling path. IMHO >>> this is no loss, as all targets/shells/batch schedulers/ etc. where >>> this might be relevant, offer functionality to redirect stderr to >>> wherever stdout goes. So there is no need for a gfortran-specific >>> mechanism for this. >> >> While this patch makes error printing thread-safe, it's no longer >> async-signal-safe as the stderr lock might lead to a deadlock. So I'm >> retracting this patch and thinking some more about this problem. > > So here is an updated patch. Compared to the status quo the main > differences are that it uses a stack allocated buffer to do the > formatting instead of a static one. This prevents conflicts from > multiple threads and in contrast to the approach in the previous patch > should also be async-signal-safe (or at least, less likely to go > belly-up when called from within a signal handler than using > vfprintf() directly). It also introduces a new function to write a > string to standard error without any formatting (estr_write), which is > simpler and less likely to cause problems than the general purpose > vs(n)printf() used before. This can be used in lieu of st_printf in > the majority of cases where no formatting is done. > > Regtested on x86_64-unknown-linux-gnu, Ok for trunk? > > frontend ChangeLog: > > 2011-05-08 Janne Blomqvist <j...@gcc.gnu.org> > > * gfortran.texi: Remove GFORTRAN_USE_STDERR documentation. > > > library ChangeLog: > > 2011-05-08 Janne Blomqvist <j...@gcc.gnu.org> > > * io/unix.c (st_vprintf,st_printf): Move to runtime/error.c. > * libgfortran.h (struct options_t): Remove use_stderr field. > (st_vprintf,st_printf): Move prototypes. > (estr_write): New prototype. > * runtime/error.c (sys_exit): Use estr_write instead of st_printf. > (estr_write): New function. > (st_vprintf): Move from io/unix.c, use stack allocated buffer, > always output to stderr. > (st_printf): Move from io/unix.c. > (show_locus): Use a local variable instead of static. > (os_error): Use estr_write instead of st_printf. > (runtime_error): Likewise. > (runtime_error_at): Likewise. > (runtime_warning_at): Likewise. > (internal_error): Likewise. > (generate_error): Likewise. > (generate_warning): Likewise. > (notify_std): Likewise. > * runtime/pause.c (do_pause): Likewise. > (pause_string): Likewise. > * runtime/stop.c (stop_string): Likewise. > (error_stop_string): Likewise. > * config/fpu_aix.h (set_fpu): Likewise. > * config/fpu_generic.h (set_fpu): Likewise. > * config/fpu_glibc.h (set_fpu): Likewise. > * config/fpu-sysv.h (set_fpu): Likewise. > * runtime/backtrace.c (dump_glibc_backtrace): Likewise. > (show_backtrace): Likewise. > * runtime/environ.c (print_spaces): Likewise. > (show_string): Likewise. > (show_variables): Likewise. > (variable_table[]): Remove GFORTRAN_USE_STDERR entry. > > > -- > Janne Blomqvist >
-- Janne Blomqvist
