Replace std/selectors with poll

std/selectors uses OS-specific selector APIs, which sounds good in
theory (faster than poll!), but sucks for portability in practice.
Sure, you can fix portability bugs, but who knows how many there are
on untested platforms... poll is standard, so if it works on one
computer it should work on all other ones. (I hope.)

As a bonus, I rewrote the timeout API for poll, which incidentally
fixes setTimeout across forks. Also, SIGWINCH should now work on all
platforms (as we self-pipe instead of signalfd/kqueue magic).

1 files changed, 2 insertions, 11 deletions

diff --git a/src/utils/sandbox.nim b/src/utils/sandbox.nim
index 9e0498a5..f7afbb91 100644
--- a/src/utils/sandbox.nim
+++ b/src/utils/sandbox.nim
@@ -175,14 +175,10 @@ elif SandboxMode == stLibSeccomp:
       "clone", # for when fork is implemented as clone
       "close", # duh
       "connect", # for outgoing requests to loader
-      "epoll_create", "epoll_create1", "epoll_ctl", "epoll_wait", # epoll stuff
-      "epoll_pwait", # for bionic & musl
-      "eventfd", # used by Nim selectors
       "exit_group", # for quit
       "fork", # for when fork is really fork
       "futex", # bionic libc & WSL both need it
       "getpid", # for determining current PID after we fork
-      "getrlimit", # glibc uses it after fork it seems
       "getsockname", # Nim needs it for connecting
       "gettimeofday", # used by QuickJS in Date.now()
       "lseek", # glibc calls lseek on open files at exit
@@ -192,17 +188,12 @@ elif SandboxMode == stLibSeccomp:
       "munmap", # memory allocation
       "pipe", # for pipes to child process
       "pipe2", # for when pipe is implemented as pipe2
-      "prlimit64", # for when getrlimit is implemented as prlimit64
+      "poll", "ppoll", # for polling (sometimes implemented as ppoll, see musl)
       "read", "recv", "recvfrom", "recvmsg", # for reading from sockets
       "rt_sigreturn", # for when sigreturn is implemented as rt_sigreturn
       "send", "sendmsg", "sendto", # for writing to sockets
       "set_robust_list", # glibc seems to need it for whatever reason
-      "setrlimit", # glibc seems to use it for whatever reason
       "sigreturn", # called by signal trampoline
-      "timerfd_create", # used by Nim selectors
-      "timerfd_gettime", # not actually used by Nim but may be in the future
-      "timerfd_settime", # used by Nim selectors
-      "ugetrlimit", # glibc uses it after fork it seems
       "write" # for writing to sockets
     ]
     for it in allowList:
@@ -235,7 +226,7 @@ elif SandboxMode == stLibSeccomp:
       "read", "write", "recv", "send", "recvfrom", "sendto", # socket i/o
       "lseek", # glibc calls lseek on open files at exit
       "mmap", "mmap2", "mremap", "munmap", "brk", # memory allocation
-      "poll", # curl needs poll
+      "poll", "ppoll", # curl needs poll
       "getpid", # used indirectly by OpenSSL EVP_RAND_CTX_new (through drbg)
       "futex", # bionic libc & WSL both need it
       # we either have to use CURLOPT_NOSIGNAL or allow signals.