Rasmus Villemoes 4b4d4056bb linux: spawni.c: simplify error reporting to parent ... Using CLONE_VFORK already ensures that the parent does not run until the child has either exec'ed succesfully or called _exit. Hence we don't need to read from a CLOEXEC pipe to ensure proper synchronization - we just make explicit use of the fact the the child and parent run in the same VM, so the child can write an error code to a field of the posix_spawn_args struct instead of sending it through a pipe. To ensure that this mechanism really works, the parent initializes the field to -1 and the child writes 0 before execing. This eliminates some annoying bookkeeping that is necessary to avoid the file actions from clobbering the write end of the pipe, and getting rid of the pipe creation in the first place means fewer system calls (four in the parent, usually one in the child) and fewer chanches for the spawn to fail (e.g. if we're close to EMFILE). Checked on x86_64 and i686. * sysdeps/unix/sysv/linux/spawni.c (posix_spawn_args): Remove pipe field, add err field. (__spawni_child): Report error through err member instead of pipe. (__spawnix): Likewise.		2016-09-28 11:16:21 -07:00
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linux	linux: spawni.c: simplify error reporting to parent	2016-09-28 11:16:21 -07:00