From af81645a2a085ab6b6f44098d54231e48d575852 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sun, 21 Jul 2019 21:43:37 +0200
Subject: [PATCH] Kernel+LibC: Add a dbgputstr() syscall for sending strings to
 debug output.

This is very handy for the DebugLogStream implementation, among others. :^)
---
 AK/LogStream.h           | 3 +--
 AK/kstdio.h              | 1 +
 Kernel/Process.cpp       | 9 +++++++++
 Kernel/Process.h         | 1 +
 Kernel/Syscall.cpp       | 2 ++
 Kernel/Syscall.h         | 3 ++-
 Kernel/kprintf.cpp       | 8 +++++++-
 Kernel/kstdio.h          | 3 +++
 Libraries/LibC/stdio.cpp | 6 ++++++
 Libraries/LibC/stdio.h   | 1 +
 10 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/AK/LogStream.h b/AK/LogStream.h
index e5906a776f1..ec88773d38f 100644
--- a/AK/LogStream.h
+++ b/AK/LogStream.h
@@ -79,8 +79,7 @@ public:
 
     virtual void write(const char* characters, int length) const override
     {
-        for (int i = 0; i < length; ++i)
-            dbgprintf("%c", characters[i]);
+        dbgputstr(characters, length);
     }
 };
 
diff --git a/AK/kstdio.h b/AK/kstdio.h
index 57a64acb7fb..3ba8c33f6f0 100644
--- a/AK/kstdio.h
+++ b/AK/kstdio.h
@@ -6,4 +6,5 @@
 #include <stdio.h>
 #define kprintf printf
 #define dbgprintf printf
+#define dbgputstr(characters, length) fwrite(characters, 1, length, stdout)
 #endif
diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 1a0e5ecbb24..e32d6b50cdc 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -2722,3 +2722,12 @@ int Process::sys$dbgputch(u8 ch)
     IO::out8(0xe9, ch);
     return 0;
 }
+
+int Process::sys$dbgputstr(const u8* characters, int length)
+{
+    if (!validate_read(characters, length))
+        return -EFAULT;
+    for (int i = 0; i < length; ++i)
+        IO::out8(0xe9, characters[i]);
+    return 0;
+}
diff --git a/Kernel/Process.h b/Kernel/Process.h
index eb603f9f775..f9dd19c3c98 100644
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@@ -105,6 +105,7 @@ public:
     void finalize();
 
     int sys$dbgputch(u8);
+    int sys$dbgputstr(const u8*, int length);
     int sys$dump_backtrace();
     int sys$gettid();
     int sys$donate(int tid);
diff --git a/Kernel/Syscall.cpp b/Kernel/Syscall.cpp
index d547f62b8bd..9334c326812 100644
--- a/Kernel/Syscall.cpp
+++ b/Kernel/Syscall.cpp
@@ -72,6 +72,8 @@ static u32 handle(RegisterDump& regs, u32 function, u32 arg1, u32 arg2, u32 arg3
         break;
     case Syscall::SC_dbgputch:
         return current->process().sys$dbgputch((u8)arg1);
+    case Syscall::SC_dbgputstr:
+        return current->process().sys$dbgputstr((const u8*)arg1, (int)arg2);
     case Syscall::SC_sleep:
         return current->process().sys$sleep((unsigned)arg1);
     case Syscall::SC_usleep:
diff --git a/Kernel/Syscall.h b/Kernel/Syscall.h
index 40a585a959c..4a365530d4d 100644
--- a/Kernel/Syscall.h
+++ b/Kernel/Syscall.h
@@ -117,7 +117,8 @@ struct timeval;
     __ENUMERATE_SYSCALL(halt)                   \
     __ENUMERATE_SYSCALL(reboot)                 \
     __ENUMERATE_SYSCALL(dump_backtrace)         \
-    __ENUMERATE_SYSCALL(dbgputch)
+    __ENUMERATE_SYSCALL(dbgputch)               \
+    __ENUMERATE_SYSCALL(dbgputstr)
 
 namespace Syscall {
 
diff --git a/Kernel/kprintf.cpp b/Kernel/kprintf.cpp
index 48a49d6b3ef..468ce55ab74 100644
--- a/Kernel/kprintf.cpp
+++ b/Kernel/kprintf.cpp
@@ -57,12 +57,18 @@ int ksprintf(char* buffer, const char* fmt, ...)
     return ret;
 }
 
+extern "C" int dbgputstr(const char* characters, int length)
+{
+    for (int i = 0; i < length; ++i)
+        IO::out8(0xe9, characters[i]);
+    return 0;
+}
+
 static void debugger_putch(char*&, char ch)
 {
     IO::out8(0xe9, ch);
 }
 
-
 extern "C" int dbgprintf(const char* fmt, ...)
 {
     color_on();
diff --git a/Kernel/kstdio.h b/Kernel/kstdio.h
index bca2bfc6242..ce7d6fdae4a 100644
--- a/Kernel/kstdio.h
+++ b/Kernel/kstdio.h
@@ -1,7 +1,10 @@
 #pragma once
 
+#include <AK/Types.h>
+
 extern "C" {
 int dbgprintf(const char* fmt, ...);
+int dbgputstr(const char*, int);
 int kprintf(const char* fmt, ...);
 int ksprintf(char* buf, const char* fmt, ...);
 }
diff --git a/Libraries/LibC/stdio.cpp b/Libraries/LibC/stdio.cpp
index 2ce4a8ab5b1..b1288a57805 100644
--- a/Libraries/LibC/stdio.cpp
+++ b/Libraries/LibC/stdio.cpp
@@ -488,6 +488,12 @@ void dbgputch(char ch)
     syscall(SC_dbgputch, ch);
 }
 
+int dbgputstr(const char* characters, int length)
+{
+    int rc = syscall(SC_dbgputstr, characters, length);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
+
 char* tmpnam(char*)
 {
     ASSERT_NOT_REACHED();
diff --git a/Libraries/LibC/stdio.h b/Libraries/LibC/stdio.h
index dd166acf20e..18214fb0e8e 100644
--- a/Libraries/LibC/stdio.h
+++ b/Libraries/LibC/stdio.h
@@ -79,6 +79,7 @@ int fprintf(FILE*, const char* fmt, ...);
 int printf(const char* fmt, ...);
 int dbgprintf(const char* fmt, ...);
 void dbgputch(char);
+int dbgputstr(const char*, ssize_t);
 int sprintf(char* buffer, const char* fmt, ...);
 int snprintf(char* buffer, size_t, const char* fmt, ...);
 int putchar(int ch);