4 files changed, 47 insertions, 1 deletions
diff --git a/include/kernel/sched.h b/include/kernel/sched.h
index 42b5b15..ac508b9 100644
--- a/include/kernel/sched.h
+++ b/include/kernel/sched.h
@@ -1,6 +1,7 @@
 #ifndef _SCHED_H
 #define _SCHED_H
 
+#include <signal.h>
 #include <stdint.h>
 #include <unistd.h>
 
@@ -39,9 +40,17 @@ struct tss_struct {
   uint32_t io_map;
 } __attribute__((packed));
 
+/*
+ * WARNING: do not modify this structure
+ * unless the offsets defined in traps.s
+ * are updated
+ */
+
 struct task_struct {
   pid_t pid;
   int state;
+  uint32_t signal;
+  void *sig_handlers[NRSIG];
   struct tss_struct tss;
 } __attribute__((packed));
 
diff --git a/include/kernel/sys.h b/include/kernel/sys.h
index 248a93b..b2c1b3b 100644
--- a/include/kernel/sys.h
+++ b/include/kernel/sys.h
@@ -4,6 +4,7 @@ extern int sys_puts(void);
 extern int sys_time(void);
 extern int sys_getpid(void);
 extern int sys_getpdir(void);
+extern int sys_signal(void);
 extern int sys_dummy(void);
 
 syscall_t call_table[256] = {
@@ -11,7 +12,7 @@ syscall_t call_table[256] = {
   [1] = &sys_time,
   [2] = &sys_getpid,
   [3] = &sys_getpdir,
-  [4] = &sys_dummy,
+  [4] = &sys_signal,
   [5] = &sys_dummy,
   [6] = &sys_dummy,
   [7] = &sys_dummy,
diff --git a/include/signal.h b/include/signal.h
new file mode 100644
index 0000000..fee6c2b
--- /dev/null
+++ b/include/signal.h
@@ -0,0 +1,35 @@
+#ifndef _SIGNAL_H
+#define _SIGNAL_H
+
+#define NRSIG 32
+
+#define SIGHUP     1
+#define SIGINT     2
+#define SIGQUIT    3
+#define SIGILL     4
+#define SIGTRAP    5
+#define SIGABRT    6
+#define SIGBUS     7
+#define SIGFPE     8
+#define SIGKILL    9
+#define SIGUSR1    10
+#define SIGSEGV    11
+#define SIGUSR2    12
+#define SIGPIPE    13
+#define SIGALRM    14
+#define SIGTERM    15
+#define SIGCHLD    17
+#define SIGCONT    18
+#define SIGSTOP    19
+#define SIGTSTP    20
+#define SIGTTIN    21
+#define SIGTTOU    22
+#define SIGURG     23
+#define SIGXCPU    24
+#define SIGXFSZ    25
+#define SIGPROF    27
+#define SIGSYS     31
+
+void *signal(int, void (*)(int));
+
+#endif
diff --git a/include/unistd.h b/include/unistd.h
index 6925541..3b144f6 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -9,6 +9,7 @@ typedef uint16_t pid_t;
 #define __SYS_time      1
 #define __SYS_getpid    2
 #define __SYS_getpdir   3
+#define __SYS_signal    4
 
 #define _syscall0(type, name) \
   type name(void) { \