Libraries: Create top level directory for libraries.

Things were getting a little crowded in the project root, so this patch
moves the Lib*/ directories into Libraries/.

Libraries/LibC/signal.cpp

@@ -0,0 +1,163 @@
+#include <Kernel/Syscall.h>
+#include <assert.h>
+#include <errno.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdio.h>
+#include <unistd.h>
+
+extern "C" {
+
+int kill(pid_t pid, int sig)
+{
+    int rc = syscall(SC_kill, pid, sig);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
+
+int killpg(int pgrp, int sig)
+{
+    int rc = syscall(SC_killpg, pgrp, sig);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
+
+int raise(int sig)
+{
+    // FIXME: Support multi-threaded programs.
+    return kill(getpid(), sig);
+}
+
+sighandler_t signal(int signum, sighandler_t handler)
+{
+    struct sigaction new_act;
+    struct sigaction old_act;
+    new_act.sa_handler = handler;
+    new_act.sa_flags = 0;
+    new_act.sa_mask = 0;
+    int rc = sigaction(signum, &new_act, &old_act);
+    if (rc < 0)
+        return SIG_ERR;
+    return old_act.sa_handler;
+}
+
+int sigaction(int signum, const struct sigaction* act, struct sigaction* old_act)
+{
+    int rc = syscall(SC_sigaction, signum, act, old_act);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
+
+int sigemptyset(sigset_t* set)
+{
+    *set = 0;
+    return 0;
+}
+
+int sigfillset(sigset_t* set)
+{
+    *set = 0xffffffff;
+    return 0;
+}
+
+int sigaddset(sigset_t* set, int sig)
+{
+    if (sig < 1 || sig > 32) {
+        errno = EINVAL;
+        return -1;
+    }
+    *set |= 1 << (sig);
+    return 0;
+}
+
+int sigdelset(sigset_t* set, int sig)
+{
+    if (sig < 1 || sig > 32) {
+        errno = EINVAL;
+        return -1;
+    }
+    *set &= ~(1 << (sig));
+    return 0;
+}
+
+int sigismember(const sigset_t* set, int sig)
+{
+    if (sig < 1 || sig > 32) {
+        errno = EINVAL;
+        return -1;
+    }
+    if (*set & (1 << (sig)))
+        return 1;
+    return 0;
+}
+
+int sigprocmask(int how, const sigset_t* set, sigset_t* old_set)
+{
+    int rc = syscall(SC_sigprocmask, how, set, old_set);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
+
+int sigpending(sigset_t* set)
+{
+    int rc = syscall(SC_sigpending, set);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
+
+const char* sys_siglist[NSIG] = {
+    "Invalid signal number",
+    "Hangup",
+    "Interrupt",
+    "Quit",
+    "Illegal instruction",
+    "Trap",
+    "Aborted",
+    "Bus error",
+    "Division by zero",
+    "Killed",
+    "User signal 1",
+    "Segmentation violation",
+    "User signal 2",
+    "Broken pipe",
+    "Alarm clock",
+    "Terminated",
+    "Stack fault",
+    "Child exited",
+    "Continued",
+    "Stopped (signal)",
+    "Stopped",
+    "Stopped (tty input)",
+    "Stopped (tty output)",
+    "Urgent I/O condition)",
+    "CPU limit exceeded",
+    "File size limit exceeded",
+    "Virtual timer expired",
+    "Profiling timer expired",
+    "Window changed",
+    "I/O possible",
+    "Power failure",
+    "Bad system call",
+};
+
+int sigsetjmp(jmp_buf env, int savesigs)
+{
+    if (savesigs) {
+        int rc = sigprocmask(0, nullptr, &env->saved_signal_mask);
+        assert(rc == 0);
+        env->did_save_signal_mask = true;
+    } else {
+        env->did_save_signal_mask = false;
+    }
+    return setjmp(env);
+}
+void siglongjmp(jmp_buf env, int val)
+{
+    if (env->did_save_signal_mask) {
+        int rc = sigprocmask(SIG_SETMASK, &env->saved_signal_mask, nullptr);
+        assert(rc == 0);
+    }
+    longjmp(env, val);
+}
+
+int sigsuspend(const sigset_t*)
+{
+    dbgprintf("FIXME: Implement sigsuspend()\n");
+    ASSERT_NOT_REACHED();
+}
+}