Merge pull request #33 from lux-operating-system/ipc-signals

src/include/kernel/sched.h

@@ -40,14 +40,27 @@
 #define WNOHANG                 0x02
 #define WUNTRACED               0x04
 
+typedef struct SignalQueue {
+    struct SignalQueue *next;
+    int signum;
+    struct Thread *sender;
+} SignalQueue;
+
 typedef struct Thread {
     int status, cpu, priority;
     pid_t pid, tid;         // pid == tid for the main thread
     uint64_t time;          // timeslice OR sleep time if sleeping thread
     lock_t lock;
 
     bool normalExit;        // true when the thread ends by exit() and is not forcefully killed
-    bool clean;             // true when the exit status has been read by waitpid() 
+    bool clean;             // true when the exit status has been read by waitpid()
+    bool handlingSignal;    // true inside a signal handler
+
+    void *signals;
+    SignalQueue *signalQueue;
+    uintptr_t signalTrampoline;
+    uintptr_t siginfo;
+    uintptr_t signalUserContext;
 
     SyscallRequest syscall; // for when the thread is blocked
     int exitStatus;         // for zombie threads
@@ -56,6 +69,7 @@ typedef struct Thread {
 
     struct Thread *next;
     void *context;          // platform-specific (page tables, registers, etc)
+    void *signalContext;
 
     uintptr_t highest;
 } Thread;

src/include/kernel/signal.h

@@ -0,0 +1,110 @@
+/*
+ * lux - a lightweight unix-like operating system
+ * Omar Elghoul, 2024
+ * 
+ * Core Microkernel
+ */
+
+#pragma once
+
+#include <sys/types.h>
+#include <kernel/sched.h>
+
+/* Signal Handler Macros */
+#define SIG_DFL         (void (*)(int))0
+#define SIG_ERR         (void (*)(int))1
+#define SIG_HOLD        (void (*)(int))2
+#define SIG_IGN         (void (*)(int))3
+
+#define SIG_T           1   /* terminate */
+#define SIG_A           2   /* abort */
+#define SIG_C           3   /* continue */
+#define SIG_S           4   /* stop */
+#define SIG_I           5   /* ignore */
+
+/* ISO C Signals */
+#define SIGABRT         1
+#define SIGFPE          2
+#define SIGILL          3
+#define SIGINT          4
+#define SIGSEGV         5
+#define SIGTERM         6
+
+/* POSIX Extension Signals */
+#define SIGALRM         7
+#define SIGBUS          8
+#define SIGCHLD         9
+#define SIGCONT         10
+#define SIGHUP          11
+#define SIGKILL         12
+#define SIGPIPE         13
+#define SIGQUIT         14
+#define SIGSTOP         15
+#define SIGTSTP         16
+#define SIGTTIN         17
+#define SIGTTOU         18
+#define SIGUSR1         19
+#define SIGUSR2         20
+#define SIGPOLL         21
+#define SIGSYS          22
+#define SIGTRAP         23
+#define SIGURG          24
+#define SIGVTALRM       25
+#define SIGXCPU         26
+#define SIGXFSZ         27
+
+#define MAX_SIGNAL      27
+
+/* Signal Flags */
+#define SA_NOCLDSTOP    0x0001
+#define SA_ONSTACK      0x0002
+#define SA_RESETHAND    0x0004
+#define SA_RESTART      0x0008
+#define SA_SIGINFO      0x0010
+#define SA_NOCLDWAIT    0x0020
+#define SA_NODEFER      0x0040
+
+#define SIG_BLOCK       0x0001
+#define SIG_UNBLOCK     0x0002
+
+#define SS_ONSTACK      0x0001
+#define SS_DISABLE      0x0002
+
+#define MINSIGSTKSZ     4096
+#define SIGSTKSZ        16384
+
+typedef volatile uint32_t sig_atomic_t;
+typedef uint64_t sigset_t;
+
+typedef struct {
+    int si_signo, si_code, si_errno, si_status;
+    pid_t si_pid;
+    uid_t si_uid;
+    void *si_addr;
+    long si_band;
+} siginfo_t;
+
+struct sigaction {
+    union {
+        void (*sa_handler)(int);
+        void (*sa_sigaction)(int, siginfo_t *, void *);
+    };
+
+    sigset_t sa_mask;
+    int sa_flags;
+};
+
+int sigemptyset(sigset_t *);
+int sigfillset(sigset_t *);
+int sigaddset(sigset_t *, int);
+int sigdelset(sigset_t *, int);
+int sigismember(sigset_t *, int);
+
+void *signalDefaults();
+int signalDefaultHandler(int);
+void *signalClone(const void *);
+void signalHandle(Thread *);
+
+int kill(Thread *, pid_t, int);
+int sigaction(Thread *, int, const struct sigaction *, struct sigaction *);
+void sigreturn(Thread *);

src/include/kernel/syscalls.h

@@ -11,10 +11,11 @@
 #include <stdbool.h>
 #include <kernel/sched.h>
 
-#define MAX_SYSCALL             56
+#define MAX_SYSCALL             58
 
 /* IPC syscall indexes, this range will be used for immediate handling without
  * waiting for the kernel thread to dispatch the syscall */
+#define SYSCALL_ACCEPT          44      // accept()
 #define SYSCALL_IPC_START       42      // bind()
 #define SYSCALL_IPC_END         46      // send()
 

src/include/platform/platform.h

@@ -61,4 +61,6 @@ int platformGetMaxIRQ();        // maximum interrupt implemented by hardware
 int platformConfigureIRQ(Thread *, int, IRQHandler *);  // configure an IRQ pin
 IRQCommand *platformGetIRQCommand();    // per-CPU IRQ command structure
 void platformIdle();            // to be called when the CPU is idle
-void platformCleanThread(void *, uintptr_t);   // garbage collector after thread is killed or replaced by exec()
+void platformCleanThread(void *, uintptr_t);   // garbage collector after thread is killed or replaced by exec()
+int platformSendSignal(Thread *, Thread *, int, uintptr_t);
+void platformSigreturn(Thread *);

src/include/stdlib.h

@@ -19,10 +19,13 @@ char *itoa(int, char *, int);
 int atoi(const char *);
 char *ltoa(long, char *, int);
 long atol(const char *);
-void *mallocUC(size_t);
 void *malloc(size_t);
 void *calloc(size_t, size_t);
 void *realloc(void *, size_t);
+void *umalloc(size_t);
+void *uxmalloc(size_t);
+void *ucalloc(size_t, size_t);
+void *urealloc(void *, size_t);
 void free(void *);
 int rand();
 void srand(unsigned int);