On Thu, 29 May 2025, Jeremy Drake via Cygwin-patches wrote:
> + /* TODO: possibly implement spawnattr flags:
> + POSIX_SPAWN_RESETIDS
> + POSIX_SPAWN_SETPGROUP
> + POSIX_SPAWN_SETSCHEDPARAM
> + POSIX_SPAWN_SETSCHEDULER
> + POSIX_SPAWN_SETSIGDEF
> + POSIX_SPAWN_SETSIGMASK */
It looks like sigmask is already passed as part of child_info, but I don't
know if there's a good way to override it other than adding yet another
parameter to child_info_spawn::worker. It took me a while to figure out
where it was getting set at all: child_info_spawn::worker calls the 'set'
method, which does a placement new over the existing 'this' pointer,
invoking the constructors.
> + case __posix_spawn_file_actions_entry::FAE_DUP2:
> + if (fae->fae_newfildes < 0 || fae->fae_newfildes > 2)
> + goto closes;
> + fds[fae->fae_newfildes] = dup (fae->fae_fildes);
> + oldflags[fae->fae_newfildes] = fcntl (fae->fae_newfildes,
> + F_GETFD, 0);
> + fcntl (fae->fae_newfildes, F_SETFD, FD_CLOEXEC);
> + break;
Minor bug-fix here
3: 713b610be3 ! 3: 999681b451 Cygwin: add fast-path for posix_spawn(p)
@@ winsup/cygwin/spawn.cc: do_posix_spawn (pid_t *pid, const char *path,
+ case __posix_spawn_file_actions_entry::FAE_DUP2:
+ if (fae->fae_newfildes < 0 || fae->fae_newfildes > 2)
+ goto closes;
-+ fds[fae->fae_newfildes] = dup (fae->fae_fildes);
++ if (fae->fae_fildes >= 0 && fae->fae_fildes <= 2 &&
++ fds[fae->fae_fildes] != -1)
++ fds[fae->fae_newfildes] = dup (fds[fae->fae_fildes]);
++ else
++ fds[fae->fae_newfildes] = dup (fae->fae_fildes);
+ oldflags[fae->fae_newfildes] = fcntl (fae->fae_newfildes,
+ F_GETFD, 0);
+ fcntl (fae->fae_newfildes, F_SETFD, FD_CLOEXEC);
> + /* TODO: FAE_(F)CHDIR */
I am not seeing how the posix cwd is passed to a spawned child. Windows
handles the cwd itself, but for cases where the cwd is virtual (say under
/proc) there must be a way to pass a cwd that Windows doesn't know
about...
