From 8066e8f1d82503834847b25543e556e774396135 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Mon, 10 Jul 2023 21:01:59 +0200
Subject: [PATCH] kernel+libc: Implement sigprocmask() and friends

---
 kernel/src/sys/signal.cpp      | 31 ++++++++++++++++++++
 libc/include/bits/signal.h     |  5 ++++
 libc/include/signal.h          | 18 ++++++++++++
 libc/src/signal.cpp            | 53 ++++++++++++++++++++++++++++++++++
 libluna/include/luna/Syscall.h |  2 +-
 5 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/kernel/src/sys/signal.cpp b/kernel/src/sys/signal.cpp
index 864fd1f8..e81952a0 100644
--- a/kernel/src/sys/signal.cpp
+++ b/kernel/src/sys/signal.cpp
@@ -2,6 +2,7 @@
 #include "memory/MemoryManager.h"
 #include "sys/Syscall.h"
 #include "thread/Scheduler.h"
+#include <bits/signal.h>
 
 Result<u64> sys_sigreturn(Registers* regs, SyscallArgs)
 {
@@ -66,3 +67,33 @@ Result<u64> sys_kill(Registers*, SyscallArgs args)
 
     return 0;
 }
+
+Result<u64> sys_sigprocmask(Registers*, SyscallArgs args)
+{
+    auto* current = Scheduler::current();
+
+    int how = (int)args[0];
+    const sigset_t* set = (const sigset_t*)args[1];
+    sigset_t* oldset = (sigset_t*)args[2];
+
+    if (oldset)
+    {
+        if (!MemoryManager::copy_to_user_typed(oldset, &current->signal_mask)) return err(EFAULT);
+    }
+
+    if (set)
+    {
+        sigset_t kset;
+        if (!MemoryManager::copy_from_user_typed(set, &kset)) return err(EFAULT);
+
+        switch (how)
+        {
+        case SIG_BLOCK: current->signal_mask |= kset;
+        case SIG_UNBLOCK: current->signal_mask &= ~kset;
+        case SIG_SETMASK: current->signal_mask = kset;
+        default: return err(EINVAL);
+        }
+    }
+
+    return 0;
+}
diff --git a/libc/include/bits/signal.h b/libc/include/bits/signal.h
index 9cc47724..2cf92f99 100644
--- a/libc/include/bits/signal.h
+++ b/libc/include/bits/signal.h
@@ -18,6 +18,11 @@ struct sigaction
     void* __sa_sigreturn = nullptr;
 };
 
+// Constants for the 'how' parameter in sigprocmask().
+#define SIG_BLOCK 0
+#define SIG_UNBLOCK 1
+#define SIG_SETMASK 2
+
 // The signals with explicit numbers have portable signal numbers.
 enum __signals
 {
diff --git a/libc/include/signal.h b/libc/include/signal.h
index b12ccb80..3cfa36cf 100644
--- a/libc/include/signal.h
+++ b/libc/include/signal.h
@@ -25,6 +25,24 @@ extern "C"
     /* Send a signal to the current thread. */
     int raise(int signo);
 
+    /* Modify the current thread's signal mask. */
+    int sigprocmask(int how, const sigset_t* set, sigset_t* oldset);
+
+    /* Clear all signals from set. */
+    int sigemptyset(sigset_t* set);
+
+    /* Add all signals to set. */
+    int sigfillset(sigset_t* set);
+
+    /* Add a specific signal to set. */
+    int sigaddset(sigset_t* set, int signo);
+
+    /* Remove a specific signal from set. */
+    int sigdelset(sigset_t* set, int signo);
+
+    /* Check if a signal is in set.*/
+    int sigismember(const sigset_t* set, int signo);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/libc/src/signal.cpp b/libc/src/signal.cpp
index 07455bdd..9b55e78b 100644
--- a/libc/src/signal.cpp
+++ b/libc/src/signal.cpp
@@ -23,4 +23,57 @@ extern "C"
     {
         return kill(getpid(), signo);
     }
+
+    int sigprocmask(int how, const sigset_t* set, sigset_t* oldset)
+    {
+        long rc = syscall(SYS_sigprocmask, how, set, oldset);
+        __errno_return(rc, int);
+    }
+
+    int sigemptyset(sigset_t* set)
+    {
+        *set = 0;
+        return 0;
+    }
+
+    int sigfillset(sigset_t* set)
+    {
+        *set = 0xffffffff;
+        return 0;
+    }
+
+    int sigaddset(sigset_t* set, int signo)
+    {
+        if (signo <= 0 || signo > NSIG)
+        {
+            errno = EINVAL;
+            return -1;
+        }
+
+        *set |= (1 << (signo - 1));
+        return 0;
+    }
+
+    int sigdelset(sigset_t* set, int signo)
+    {
+        if (signo <= 0 || signo > NSIG)
+        {
+            errno = EINVAL;
+            return -1;
+        }
+
+        *set &= ~(1 << (signo - 1));
+        return 0;
+    }
+
+    int sigismember(const sigset_t* set, int signo)
+    {
+        if (signo <= 0 || signo > NSIG)
+        {
+            errno = EINVAL;
+            return -1;
+        }
+
+        return (*set & (1 << (signo - 1))) > 0;
+    }
 }
diff --git a/libluna/include/luna/Syscall.h b/libluna/include/luna/Syscall.h
index 93db68ab..c89beb66 100644
--- a/libluna/include/luna/Syscall.h
+++ b/libluna/include/luna/Syscall.h
@@ -6,7 +6,7 @@
             _e(getgid) _e(getegid) _e(setuid) _e(setgid) _e(seteuid) _e(setegid) _e(fchmodat) _e(fchownat) _e(ioctl)   \
                 _e(fstatat) _e(chdir) _e(getcwd) _e(unlinkat) _e(uname) _e(sethostname) _e(dup2) _e(pipe) _e(mount)    \
                     _e(umount) _e(pstat) _e(getrusage) _e(symlinkat) _e(readlinkat) _e(umask) _e(linkat) _e(faccessat) \
-                        _e(pivot_root) _e(sigreturn) _e(sigaction) _e(kill)
+                        _e(pivot_root) _e(sigreturn) _e(sigaction) _e(kill) _e(sigprocmask)
 
 enum Syscalls
 {