diff options
Diffstat (limited to 'gdb/procfs.c')
| -rw-r--r-- | gdb/procfs.c | 65 |
1 files changed, 25 insertions, 40 deletions
diff --git a/gdb/procfs.c b/gdb/procfs.c index 5ebc5e0..c9e0d8f 100644 --- a/gdb/procfs.c +++ b/gdb/procfs.c @@ -2174,48 +2174,33 @@ do_detach (signal) attach_flag = 0; } -/* - -LOCAL FUNCTION - - procfs_wait -- emulate wait() as much as possible - Wait for child to do something. Return pid of child, or -1 in case - of error; store status through argument pointer STATUS. - - -SYNOPSIS - - int procfs_wait (int pid, int *statloc) - -DESCRIPTION - - Try to emulate wait() as much as possible. Not sure why we can't - just use wait(), but it seems to have problems when applied to a - process being controlled with the /proc interface. - -NOTES - - We have a race problem here with no obvious solution. We need to let - the inferior run until it stops on an event of interest, which means - that we need to use the PIOCWSTOP ioctl. However, we cannot use this - ioctl if the process is already stopped on something that is not an - event of interest, or the call will hang indefinitely. Thus we first - use PIOCSTATUS to see if the process is not stopped. If not, then we - use PIOCWSTOP. But during the window between the two, if the process - stops for any reason that is not an event of interest (such as a job - control signal) then gdb will hang. One possible workaround is to set - an alarm to wake up every minute of so and check to see if the process - is still running, and if so, then reissue the PIOCWSTOP. But this is - a real kludge, so has not been implemented. FIXME: investigate - alternatives. - - FIXME: Investigate why wait() seems to have problems with programs - being control by /proc routines. - - */ +/* emulate wait() as much as possible. + Wait for child to do something. Return pid of child, or -1 in case + of error; store status in *OURSTATUS. + + Not sure why we can't + just use wait(), but it seems to have problems when applied to a + process being controlled with the /proc interface. + + We have a race problem here with no obvious solution. We need to let + the inferior run until it stops on an event of interest, which means + that we need to use the PIOCWSTOP ioctl. However, we cannot use this + ioctl if the process is already stopped on something that is not an + event of interest, or the call will hang indefinitely. Thus we first + use PIOCSTATUS to see if the process is not stopped. If not, then we + use PIOCWSTOP. But during the window between the two, if the process + stops for any reason that is not an event of interest (such as a job + control signal) then gdb will hang. One possible workaround is to set + an alarm to wake up every minute of so and check to see if the process + is still running, and if so, then reissue the PIOCWSTOP. But this is + a real kludge, so has not been implemented. FIXME: investigate + alternatives. + + FIXME: Investigate why wait() seems to have problems with programs + being control by /proc routines. */ static int -procfs_wait (pid, statloc) +procfs_wait (pid, ourstatus) int pid; struct target_waitstatus *ourstatus; { |