From: Matthias Kruk <m@m10k.eu>
Date: Sun, 5 Jan 2020 06:27:34 +0000 (+0900)
Subject: Add debug syscall for low-level/last-resort debugging
X-Git-Url: https://git.corax.cc/?a=commitdiff_plain;h=1cc3fb1fcb51af6ef8bda7cbe2d3be76b1fc574b;p=corax

Add debug syscall for low-level/last-resort debugging
---

diff --git a/config.h b/config.h
index 923be4f..758607f 100644
--- a/config.h
+++ b/config.h
@@ -46,6 +46,7 @@
 #define CONFIG_DEBUG_NET   1
 #define CONFIG_DEBUG_IPC   1
 #define CONFIG_DEBUG_HEAP  0
+#define CONFIG_DEBUG_SYSDEBUG 1
 
 #define CONFIG_SOCKET_MAX    1024
 #define CONFIG_NET_MBUF_SIZE 2048
diff --git a/include/corax/syscall.h b/include/corax/syscall.h
index 07b64cd..9c7fed0 100644
--- a/include/corax/syscall.h
+++ b/include/corax/syscall.h
@@ -30,6 +30,8 @@
 #define SYS_INB        11
 #define SYS_OUTB       12
 
+#define SYS_DEBUG      13
+
 /* Corax-specific variations of POSIX syscalls */
 #define SYS_EXECFVE    128
 
diff --git a/kernel/core/posixcall.c b/kernel/core/posixcall.c
index f0fa769..289a9ee 100644
--- a/kernel/core/posixcall.c
+++ b/kernel/core/posixcall.c
@@ -405,6 +405,25 @@ int sys_outb(stack_frame_t *stk)
 	return(0);
 }
 
+#if FEATURE(DEBUG_SYSDEBUG)
+int sys_debug(const char *str, const u32_t len)
+{
+	char buffer[128];
+	int ret_val;
+	process_t *cproc;
+
+	cproc = process_get_current();
+	ret_val = len < sizeof(buffer) ? len : sizeof(buffer);
+
+	process_memcpy_ptok(cproc, buffer, str, ret_val);
+	buffer[sizeof(buffer) - 1] = 0;
+
+	dbg_printf("%s\n", buffer);
+
+	return(ret_val);
+}
+#endif /* FEATURE(DEBUG_SYSDEBUG) */
+
 int sys_posixcall(stack_frame_t *stk)
 {
 	int ret_val;
@@ -473,6 +492,12 @@ int sys_posixcall(stack_frame_t *stk)
 		ret_val = sys_outb(stk);
 		break;
 
+#if FEATURE(DEBUG_SYSDEBUG)
+	case SYS_DEBUG:
+		ret_val = sys_debug((const char*)stk->ebx, (u32_t)stk->ecx);
+		break;
+#endif /* FEATURE(DEBUG_SYSDEBUG) */
+
 	default:
 		ret_val = -EOPNOTSUPP;
 		break;
diff --git a/kernel/klibc/posixcall.S b/kernel/klibc/posixcall.S
index ecc6004..9d7479f 100644
--- a/kernel/klibc/posixcall.S
+++ b/kernel/klibc/posixcall.S
@@ -15,6 +15,10 @@
 	.global mmap
 	.global munmap
 
+#if FEATURE(DEBUG_SYSDEBUG)
+	.global debug
+#endif /* FEATURE(DEBUG_SYSDEBUG) */
+
 _exit:
 	pushl	%ebx
 
@@ -102,4 +106,18 @@ munmap:
 	popl	%ebx
 	ret
 
+#if FEATURE(DEBUG_SYSDEBUG)
+debug:
+	pushl	%ebx
+
+	movl	$SYS_DEBUG, %eax
+	movl	8(%esp), %ebx
+	movl	12(%esp), %ecx
+	int		$SYSCALL_POSIX
+
+	popl	%ebx
+	ret
+
+#endif /* FEATURE(DEBUG_SYSDEBUG) */
+
 #endif /* FEATURE(POSIX) */