From db525dc2ada7fbedf4e9d4fbb2bc8a10b951acab Mon Sep 17 00:00:00 2001
From: Theodore Dubois <tblodt@icloud.com>
Date: Tue, 30 Oct 2018 16:59:12 -0700
Subject: [PATCH] Implement pselect

---
 kernel/calls.c  |  1 +
 kernel/calls.h  |  1 +
 kernel/poll.c   | 20 ++++++++++++++++++++
 kernel/signal.c | 37 +++++++++++++++++++++++--------------
 kernel/signal.h |  1 +
 5 files changed, 46 insertions(+), 14 deletions(-)

diff --git a/kernel/calls.c b/kernel/calls.c
index b01cfcea..6bf19e3a 100644
--- a/kernel/calls.c
+++ b/kernel/calls.c
@@ -122,6 +122,7 @@ syscall_t syscall_table[] = {
     [305] = (syscall_t) sys_readlinkat,
     [306] = (syscall_t) sys_fchmodat,
     [307] = (syscall_t) sys_faccessat,
+    [308] = (syscall_t) sys_pselect,
     [320] = (syscall_t) sys_utimensat,
     [324] = (syscall_t) sys_fallocate,
     [340] = (syscall_t) sys_prlimit,
diff --git a/kernel/calls.h b/kernel/calls.h
index 5c8f32f8..96984c28 100644
--- a/kernel/calls.h
+++ b/kernel/calls.h
@@ -190,6 +190,7 @@ struct pollfd_ {
 };
 dword_t sys_poll(addr_t fds, dword_t nfds, dword_t timeout);
 dword_t sys_select(fd_t nfds, addr_t readfds_addr, addr_t writefds_addr, addr_t exceptfds_addr, addr_t timeout_addr);
+dword_t sys_pselect(fd_t nfds, addr_t readfds_addr, addr_t writefds_addr, addr_t exceptfds_addr, addr_t timeout_addr, addr_t sigmask_addr);
 
 // misc
 dword_t sys_futex(addr_t uaddr, dword_t op, dword_t val);
diff --git a/kernel/poll.c b/kernel/poll.c
index 8b718660..2d67cdd0 100644
--- a/kernel/poll.c
+++ b/kernel/poll.c
@@ -134,3 +134,23 @@ dword_t sys_poll(addr_t fds, dword_t nfds, dword_t timeout) {
             return _EFAULT;
     return err;
 }
+
+dword_t sys_pselect(fd_t nfds, addr_t readfds_addr, addr_t writefds_addr, addr_t exceptfds_addr, addr_t timeout_addr, addr_t sigmask_addr) {
+    // a system call can only take 6 parameters, so the last two need to be passed as a pointer to a struct
+    struct {
+        addr_t mask_addr;
+        dword_t mask_size;
+    } sigmask;
+    if (user_get(sigmask_addr, sigmask))
+        return _EFAULT;
+    if (sigmask.mask_size != sizeof(sigset_t_))
+        return _EINVAL;
+    sigset_t_ mask, old_mask;
+    if (user_get(sigmask.mask_addr, mask))
+        return _EFAULT;
+
+    do_sigprocmask(SIG_SETMASK_, mask, &old_mask);
+    dword_t res = sys_select(nfds, readfds_addr, writefds_addr, exceptfds_addr, timeout_addr);
+    do_sigprocmask(SIG_SETMASK_, old_mask, NULL);
+    return res;
+}
diff --git a/kernel/signal.c b/kernel/signal.c
index f9dec93b..430b82d3 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -213,22 +213,11 @@ dword_t sys_sigaction(dword_t signum, addr_t action_addr, addr_t oldaction_addr)
     return sys_rt_sigaction(signum, action_addr, oldaction_addr, 1);
 }
 
-dword_t sys_rt_sigprocmask(dword_t how, addr_t set_addr, addr_t oldset_addr, dword_t size) {
-    if (size != sizeof(sigset_t_))
-        return _EINVAL;
-
-    sigset_t_ set;
-    if (user_get(set_addr, set))
-        return _EFAULT;
-    STRACE("rt_sigprocmask(%s, 0x%llx, 0x%x, %d)",
-            how == SIG_BLOCK_ ? "SIG_BLOCK" :
-            how == SIG_UNBLOCK_ ? "SIG_UNBLOCK" :
-            how == SIG_SETMASK_ ? "SIG_SETMASK" : "??",
-            (long long) set, oldset_addr, size);
-    sigset_t_ oldset = current->blocked;
-
+int do_sigprocmask(dword_t how, sigset_t_ set, sigset_t_ *oldset_out) {
     struct sighand *sighand = current->sighand;
     lock(&sighand->lock);
+    sigset_t oldset = current->blocked;
+
     if (how == SIG_BLOCK_)
         current->blocked |= set;
     else if (how == SIG_UNBLOCK_)
@@ -245,7 +234,27 @@ dword_t sys_rt_sigprocmask(dword_t how, addr_t set_addr, addr_t oldset_addr, dwo
     current->pending |= current->queued & unblocked;
     current->queued &= ~unblocked;
     unlock(&sighand->lock);
+    if (oldset_out != NULL)
+        *oldset_out = current->blocked;
+    return 0;
+}
 
+dword_t sys_rt_sigprocmask(dword_t how, addr_t set_addr, addr_t oldset_addr, dword_t size) {
+    if (size != sizeof(sigset_t_))
+        return _EINVAL;
+
+    sigset_t_ set, oldset;
+    if (user_get(set_addr, set))
+        return _EFAULT;
+    STRACE("rt_sigprocmask(%s, 0x%llx, 0x%x, %d)",
+            how == SIG_BLOCK_ ? "SIG_BLOCK" :
+            how == SIG_UNBLOCK_ ? "SIG_UNBLOCK" :
+            how == SIG_SETMASK_ ? "SIG_SETMASK" : "??",
+            (long long) set, oldset_addr, size);
+
+    int err = do_sigprocmask(how, set, &oldset);
+    if (err < 0)
+        return err;
     if (oldset_addr != 0)
         if (user_put(oldset_addr, oldset))
             return _EFAULT;
diff --git a/kernel/signal.h b/kernel/signal.h
index 7f87ed7e..654d7b98 100644
--- a/kernel/signal.h
+++ b/kernel/signal.h
@@ -81,6 +81,7 @@ dword_t sys_rt_sigreturn(dword_t sig);
 #define SIG_UNBLOCK_ 1
 #define SIG_SETMASK_ 2
 typedef uint64_t sigset_t_;
+int do_sigprocmask(dword_t how, sigset_t_ set, sigset_t_ *oldset);
 dword_t sys_rt_sigprocmask(dword_t how, addr_t set, addr_t oldset, dword_t size);
 
 struct stack_t_ {