On FreeBSD using ghc 4.04, long running commands executed with
System.system are being interrupted by virtual alarms leading to
errors such as:
o Fail: interrupted
Action: system
Reason: system command interrupted rm -f xxx yyy
o Virtual timer expired
o gcc: Internal
Hello!
On Fri, Mar 17, 2000 at 01:42:14AM -0800, Simon Marlow wrote:
[...]
After looking at ghc 4.02's libraries for a while (it's all I had
around), it looks as though ghc-4.02/ghc/lib/std/cbits/system.c should
mask the SIGVTALRM signal after executing fork and before executing
exec*.
Hello!
On Fri, Mar 17, 2000 at 01:46:03AM -0800, Simon Marlow wrote:
I don't get it - execve() and friends are supposed to reset
all the signal
handlers back to the default state, aren't they? And I can't seem to
construct an example to demonstrate the problem.
Ah, I get it finally
The correct handling would be:
- block SIGALRM/SIGVTALRM/SIGPROF
- *then* fork() (else you have a race condition where the child could
receive *and handle* the signal)
This race condition is harmless, I think. The VTALRM handler just
increments a counter, and we're about to blow away this
