Add setsid(2) syscall

arch/amd64/syscall.c

@@ -82,6 +82,7 @@ void *syscall_table[256] = {
     [SYSCALL_NRX_WAITPID] =         sys_waitpid,
     [SYSCALL_NR_GETPGID] =          sys_getpgid,
     [SYSCALL_NR_SETPGID] =          sys_setpgid,
+    [SYSCALL_NR_SETSID] =           sys_setsid,
     [SYSCALL_NR_SIGALTSTACK] =      sys_sigaltstack,
     [SYSCALL_NR_GETPPID] =          sys_getppid,
 

include/sys/sys_proc.h

@@ -11,6 +11,7 @@ int sys_clone(int (*entry) (void *), void *stack, int flags, void *arg);
 int sys_execve(const char *path, const char **argp, const char **envp);
 pid_t sys_getpid(void);
 pid_t sys_getppid(void);
+pid_t sys_setsid(void);
 
 uid_t sys_getuid(void);
 gid_t sys_getgid(void);

include/sys/thread.h

@@ -94,8 +94,9 @@ struct process {
     // Signal
     uint64_t sigq;
 
-    // procfs
+    // Filesystem-stuff
     struct vnode *fs_entry;
+    struct vnode *ctty;
 
     // State
     char name[256];

include/user/syscall.h

@@ -52,6 +52,7 @@
 #define SYSCALL_NR_SETGID           106
 #define SYSCALL_NR_SETPGID          109
 #define SYSCALL_NR_GETPPID          110
+#define SYSCALL_NR_SETSID           112
 #define SYSCALL_NR_GETPGID          121
 #define SYSCALL_NR_SIGALTSTACK      131
 #define SYSCALL_NRX_WAITPID         247

sys/char/tty.c

@@ -174,9 +174,13 @@ void tty_putc(struct chrdev *tty, int c) {
 }
 
 static struct vnode *tty_link_getter(struct thread *ctx, struct vnode *link) {
-    struct vnode *res;
-    dev_find(DEV_CLASS_CHAR, "tty0", &res);
-    return res;
+    struct process *proc;
+
+    if (!(proc = ctx->proc)) {
+        return NULL;
+    }
+
+    return proc->ctty;
 }
 
 void tty_init(void) {
@@ -209,10 +213,15 @@ static int tty_ioctl(struct chrdev *tty, unsigned int cmd, void *arg) {
         {
             _assert(arg);
             struct winsize *winsz = arg;
-            _assert(data->master);
+            if (data->has_console) {
+                _assert(data->master);
 
-            winsz->ws_col = data->master->width_chars;
-            winsz->ws_row = data->master->height_chars;
+                winsz->ws_col = data->master->width_chars;
+                winsz->ws_row = data->master->height_chars;
+            } else {
+                winsz->ws_col = 80;
+                winsz->ws_row = 25;
+            }
         }
         return 0;
     case TCGETS:

sys/init.c

@@ -57,6 +57,8 @@ static void user_init_func(void *arg) {
     _assert(fd_stdin->refcount == 1);
     _assert(fd_stdout->refcount == 2);
 
+    thread_self->proc->ctty = tty_dev;
+
     const char *argp[] = {
         "/init", NULL
     };

sys/sys_file.c

@@ -195,6 +195,18 @@ int sys_openat(int dfd, const char *filename, int flags, int mode) {
     proc->fds[fd] = ofile_dup(ofile);
     _assert(proc->fds[fd]->refcount == 1);
 
+    // Set controlling terminal if none present and TTY is opened
+    // TODO: O_NOCTTY
+    if (!proc->ctty && !(ofile->flags & OF_SOCKET)) {
+        struct vnode *node = ofile->file.vnode;
+        _assert(node);
+
+        if (node->type == VN_CHR && ((struct chrdev *) node->dev)->type == CHRDEV_TTY) {
+            kdebug("Setting controlling terminal for #%d (%s)\n", proc->pid, proc->name);
+            proc->ctty = node;
+        }
+    }
+
     return fd;
 }
 

sys/thread.c

@@ -325,6 +325,7 @@ int process_init_thread(struct process *proc, uintptr_t entry, void *arg, int us
     proc->next_child = NULL;
     proc->pgid = -1;
     proc->pid = process_alloc_pid(user);
+    proc->ctty = NULL;
     kdebug("New process #%d with main thread <%p>", proc->pid, main_thread);
 
     proc->sigq = 0;
@@ -570,6 +571,7 @@ int sys_fork(struct sys_fork_frame *frame) {
     dst->pgid = src->pgid;
     dst->sigq = 0;
     dst->proc_state = PROC_ACTIVE;
+    dst->ctty = src->ctty;
     kdebug("New process #%d with main thread <%p>\n", dst->pid, dst_thread);
 
     // Initialize dst thread
@@ -723,7 +725,7 @@ __attribute__((noreturn)) void sys_exit(int status) {
         sched_unqueue(thr, THREAD_STOPPED);
         panic("This code shouldn't run\n");
     }
-    kdebug("Process %d exited with status %d\n", proc->pid, status);
+    kdebug("Process #%d (%s) exited with status %d\n", proc->pid, proc->name, status);
 
     // Clear pending I/O (if exiting from signal interrupting select())
     if (!list_empty(&thr->wait_head)) {
@@ -987,3 +989,25 @@ uid_t sys_getuid(void) {
 gid_t sys_getgid(void) {
     return thread_self->proc->ioctx.gid;
 }
+
+pid_t sys_setsid(void) {
+    struct process *proc = thread_self->proc;
+    _assert(proc);
+    if (proc->ctty) {
+        // Close current tty filedes
+        for (size_t i = 0; i < THREAD_MAX_FDS; ++i) {
+            if (proc->fds[i] && !(proc->fds[i]->flags & OF_SOCKET)) {
+                if (proc->fds[i]->file.vnode == proc->ctty) {
+                    kdebug("setsid: detaching fd %d from #%d (%s)\n", i, proc->pid, proc->name);
+                    ofile_close(&proc->ioctx, proc->fds[i]);
+                    proc->fds[i] = NULL;
+                }
+            }
+        }
+        proc->ctty = NULL;
+    } else {
+        kdebug("setsid: #%d (%s) didn't have a tty\n", proc->pid, proc->name);
+    }
+
+    return proc->pid;
+}