From 52064e0317fb0f351147f78fa1d3f1fe4287f793 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Fri, 11 Aug 2023 18:09:12 +0200
Subject: [PATCH] libc+kernel: Add alarm() and getpagesize()

---
 kernel/CMakeLists.txt           |  1 +
 kernel/src/sys/alarm.cpp        | 15 +++++++++++++++
 kernel/src/thread/Scheduler.cpp |  2 ++
 kernel/src/thread/Thread.h      |  1 +
 libc/include/unistd.h           |  6 ++++++
 libc/src/unistd.cpp             | 11 +++++++++++
 6 files changed, 36 insertions(+)
 create mode 100644 kernel/src/sys/alarm.cpp

diff --git a/kernel/CMakeLists.txt b/kernel/CMakeLists.txt
index fa7f4f62..c77e1236 100644
--- a/kernel/CMakeLists.txt
+++ b/kernel/CMakeLists.txt
@@ -44,6 +44,7 @@ set(SOURCES
     src/sys/signal.cpp
     src/sys/socket.cpp
     src/sys/poll.cpp
+    src/sys/alarm.cpp
     src/fs/VFS.cpp
     src/fs/Pipe.cpp
     src/fs/Mount.cpp
diff --git a/kernel/src/sys/alarm.cpp b/kernel/src/sys/alarm.cpp
new file mode 100644
index 00000000..c4f8d7d8
--- /dev/null
+++ b/kernel/src/sys/alarm.cpp
@@ -0,0 +1,15 @@
+#include "sys/Syscall.h"
+#include "thread/Scheduler.h"
+
+Result<u64> sys_alarm(Registers*, SyscallArgs args)
+{
+    unsigned int seconds = (unsigned int)args[0];
+
+    auto* current = Scheduler::current();
+
+    u64 time_left = current->alarm_ticks_left;
+
+    current->alarm_ticks_left = seconds * 1000;
+
+    return time_left * 1000;
+}
diff --git a/kernel/src/thread/Scheduler.cpp b/kernel/src/thread/Scheduler.cpp
index d5d5df16..d72384e7 100644
--- a/kernel/src/thread/Scheduler.cpp
+++ b/kernel/src/thread/Scheduler.cpp
@@ -282,6 +282,8 @@ namespace Scheduler
             {
                 if (thread->sleep_ticks_left == 0 || --thread->sleep_ticks_left == 0) thread->wake_up();
             }
+
+            if (thread->alarm_ticks_left && --thread->alarm_ticks_left == 0) thread->send_signal(SIGALRM);
         }
 
         if (!g_current->ticks_left) switch_task(regs);
diff --git a/kernel/src/thread/Thread.h b/kernel/src/thread/Thread.h
index 90edd7ea..78ee01d8 100644
--- a/kernel/src/thread/Thread.h
+++ b/kernel/src/thread/Thread.h
@@ -87,6 +87,7 @@ struct Thread : public LinkedListNode<Thread>
 
     u64 ticks_left;
     u64 sleep_ticks_left;
+    u64 alarm_ticks_left { 0 };
 
     Stack stack;
     Stack kernel_stack;
diff --git a/libc/include/unistd.h b/libc/include/unistd.h
index d2966a07..5ec8b5c2 100644
--- a/libc/include/unistd.h
+++ b/libc/include/unistd.h
@@ -190,6 +190,12 @@ extern "C"
     /* Truncate a file to a specific length. */
     int ftruncate(int fd, size_t size);
 
+    /* Return the system page size. */
+    int getpagesize(void);
+
+    /* Schedule an alarm signal. */
+    unsigned int alarm(unsigned int seconds);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/libc/src/unistd.cpp b/libc/src/unistd.cpp
index c9d4741d..e2501a51 100644
--- a/libc/src/unistd.cpp
+++ b/libc/src/unistd.cpp
@@ -8,6 +8,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/ioctl.h>
+#include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/syscall.h>
 #include <sys/utsname.h>
@@ -510,4 +511,14 @@ extern "C"
         long rc = syscall(SYS_ftruncate, fd, size);
         __errno_return(rc, int);
     }
+
+    int getpagesize(void)
+    {
+        return PAGE_SIZE;
+    }
+
+    unsigned int alarm(unsigned int seconds)
+    {
+        return (unsigned int)syscall(SYS_alarm, seconds);
+    }
 }