kernel: Add initial support for signals

Signed-off-by: Ian Moffett <ian@osmora.org>

2 files changed, 89 insertions, 0 deletions

diff --git a/sys/include/sys/proc.h b/sys/include/sys/proc.h
index b9db603..b10ee41 100644
--- a/sys/include/sys/proc.h
+++ b/sys/include/sys/proc.h
@@ -38,6 +38,7 @@
 #include <sys/syscall.h>
 #include <sys/exec.h>
 #include <sys/filedesc.h>
+#include <sys/signal.h>
 #if defined(_KERNEL)
 #include <machine/frame.h>
 #include <machine/pcb.h>
@@ -48,10 +49,12 @@
 #define PROC_STACK_PAGES 8
 #define PROC_STACK_SIZE  (PROC_STACK_PAGES * DEFAULT_PAGESIZE)
 #define PROC_MAX_FILEDES 256
+#define PROC_SIGMAX 64
 
 struct proc {
     pid_t pid;
     struct exec_prog exec;
+    struct ksiginfo *ksig_list[PROC_SIGMAX];
     struct filedesc *fds[PROC_MAX_FILEDES];
     struct trapframe tf;
     struct pcb pcb;
@@ -59,6 +62,8 @@ struct proc {
     bool rested;
     uint32_t flags;
     uintptr_t stack_base;
+    struct spinlock ksigq_lock;
+    TAILQ_HEAD(, ksiginfo) ksigq;
     TAILQ_ENTRY(proc) link;
 };
 
diff --git a/sys/include/sys/signal.h b/sys/include/sys/signal.h
new file mode 100644
index 0000000..f35ff82
--- /dev/null
+++ b/sys/include/sys/signal.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _SYS_SIGNAL_H_
+#define _SYS_SIGNAL_H_
+
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/proc.h>
+
+#define SIGFPE      8   /* Floating point exception */
+#define SIGKILL     9   /* Kill */
+#define SIGSEGV     11  /* Segmentation violation */
+
+typedef uint32_t sigset_t;
+
+typedef struct {
+    int si_signo;
+    int si_code;
+} siginfo_t;
+
+struct sigaction {
+    void(*sa_handler)(int signo);
+    sigset_t sa_mask;
+    int sa_flags;
+    void(*sa_sigaction)(int signo, siginfo_t *si, void *p);
+};
+
+#if defined(_KERNEL)
+struct proc;
+
+struct ksiginfo {
+    int signo;
+    int sigcode;
+    struct sigaction *si;
+    TAILQ_ENTRY(ksiginfo) link;
+};
+
+/* Signal management */
+int newsig(struct proc *td, int signo, struct ksiginfo **ksig);
+int delsig(struct proc *td, int signo);
+int sendsig(struct proc *td, const sigset_t *set);
+void dispatch_signals(struct proc *td);
+int signals_init(struct proc *td);
+
+/* Sigset functions */
+int sigemptyset(sigset_t *set);
+int sigfillset(sigset_t *set);
+int sigaddset(sigset_t *set, int signo);
+int sigdelset(sigset_t *set, int signo);
+int sigismember(const sigset_t *set, int signo);
+
+/* Default handlers */
+void sigfpe_default(int signo);
+void sigkill_default(int signo);
+void sigsegv_default(int signo);
+#endif  /* _KERNEL */
+#endif  /* !_SYS_SIGNAL_H_ */