14.06.2023 23:30, Michael Tokarev пишет:
13.06.2023 17:30, Denys Vlasenko wrote:
I think we can delay daemonizing in both cases.
Please try current git.
Yes, your version is better, it is definitely cleaner, especially
after the preparational patch.
But does it work for non-MMU case?
Or will it just open /dev/log twice and everything will be ok?
Actually it doesn't work on regular system too, the fd#0 is redirected
from /dev/null somewhere down the line and enters a tight loop:
44138 readlink("/dev/log", "/run/systemd/journal/dev-log", 80) = 28
44138 readlink("/run/systemd/journal/dev-log", 0x5611c6c26ee0, 80) = -1 EINVAL
(Invalid argument)
44138 unlink("/run/systemd/journal/dev-log") = 0
44138 socket(AF_UNIX, SOCK_DGRAM, 0) = 3
44138 bind(3, {sa_family=AF_UNIX, sun_path="/run/systemd/journal/dev-log"},
110) = 0
44138 chmod("/dev/log", 0666) = 0
44138 dup2(3, 0) = 0
44138 close(3) = 0
44138 chdir("/") = 0
44138 openat(AT_FDCWD, "/dev/null", O_RDWR) = 3
44138 clone(child_stack=NULL,
flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
child_tidptr=0x7fb6bc72fa10) = 44139
44138 exit_group(0) = ?
44138 +++ exited with 0 +++
44139 set_robust_list(0x7fb6bc72fa20, 24) = 0
44139 setsid() = 44139
44139 dup2(3, 0) = 0
44139 dup2(3, 1) = 1
44139 dup2(3, 2) = 2
44139 close(3) = 0
It is done in bb_daemonize_or_rexec(). Which, it seems,
can be optimized too, to avoid duplicate dup(0,1,2) case.
This is why I used extra variable 'int fd = .. xmove_fd(fd)'.
(btw, should it chmod the result of readlink, not /dev/log? - probably doesn't
matter).
Thanks,
/mjt
/mjt
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