Import of Linus's Linux 1.1.68

1 files changed, 603 insertions, 0 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
new file mode 100644
index 000000000..b2a8c4fb0
--- /dev/null
+++ b/kernel/exit.c
@@ -0,0 +1,603 @@
+/*
+ *  linux/kernel/exit.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#define DEBUG_PROC_TREE
+
+#include <linux/wait.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/resource.h>
+#include <linux/mm.h>
+#include <linux/tty.h>
+#include <linux/malloc.h>
+
+#include <asm/segment.h>
+extern void sem_exit (void);
+
+int getrusage(struct task_struct *, int, struct rusage *);
+
+static int generate(unsigned long sig, struct task_struct * p)
+{
+	unsigned long mask = 1 << (sig-1);
+	struct sigaction * sa = sig + p->sigaction - 1;
+
+	/* always generate signals for traced processes ??? */
+	if (p->flags & PF_PTRACED) {
+		p->signal |= mask;
+		return 1;
+	}
+	/* don't bother with ignored signals (but SIGCHLD is special) */
+	if (sa->sa_handler == SIG_IGN && sig != SIGCHLD)
+		return 0;
+	/* some signals are ignored by default.. (but SIGCONT already did its deed) */
+	if ((sa->sa_handler == SIG_DFL) &&
+	    (sig == SIGCONT || sig == SIGCHLD || sig == SIGWINCH))
+		return 0;
+	p->signal |= mask;
+	return 1;
+}
+
+int send_sig(unsigned long sig,struct task_struct * p,int priv)
+{
+	if (!p || sig > 32)
+		return -EINVAL;
+	if (!priv && ((sig != SIGCONT) || (current->session != p->session)) &&
+	    (current->euid != p->euid) && (current->uid != p->uid) && !suser())
+		return -EPERM;
+	if (!sig)
+		return 0;
+	/*
+	 * Forget it if the process is already zombie'd.
+	 */
+	if (p->state == TASK_ZOMBIE)
+		return 0;
+	if ((sig == SIGKILL) || (sig == SIGCONT)) {
+		if (p->state == TASK_STOPPED)
+			p->state = TASK_RUNNING;
+		p->exit_code = 0;
+		p->signal &= ~( (1<<(SIGSTOP-1)) | (1<<(SIGTSTP-1)) |
+				(1<<(SIGTTIN-1)) | (1<<(SIGTTOU-1)) );
+	}
+	/* Depends on order SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU */
+	if ((sig >= SIGSTOP) && (sig <= SIGTTOU)) 
+		p->signal &= ~(1<<(SIGCONT-1));
+	/* Actually generate the signal */
+	generate(sig,p);
+	return 0;
+}
+
+void notify_parent(struct task_struct * tsk)
+{
+	if (tsk->p_pptr == task[1])
+		tsk->exit_signal = SIGCHLD;
+	send_sig(tsk->exit_signal, tsk->p_pptr, 1);
+	wake_up_interruptible(&tsk->p_pptr->wait_chldexit);
+}
+
+void release(struct task_struct * p)
+{
+	int i;
+
+	if (!p)
+		return;
+	if (p == current) {
+		printk("task releasing itself\n");
+		return;
+	}
+	for (i=1 ; i<NR_TASKS ; i++)
+		if (task[i] == p) {
+			task[i] = NULL;
+			REMOVE_LINKS(p);
+			if (STACK_MAGIC != *(unsigned long *)p->kernel_stack_page)
+				printk(KERN_ALERT "release: %s kernel stack corruption. Aiee\n", p->comm);
+			free_page(p->kernel_stack_page);
+			free_page((long) p);
+			return;
+		}
+	panic("trying to release non-existent task");
+}
+
+#ifdef DEBUG_PROC_TREE
+/*
+ * Check to see if a task_struct pointer is present in the task[] array
+ * Return 0 if found, and 1 if not found.
+ */
+int bad_task_ptr(struct task_struct *p)
+{
+	int 	i;
+
+	if (!p)
+		return 0;
+	for (i=0 ; i<NR_TASKS ; i++)
+		if (task[i] == p)
+			return 0;
+	return 1;
+}
+	
+/*
+ * This routine scans the pid tree and makes sure the rep invariant still
+ * holds.  Used for debugging only, since it's very slow....
+ *
+ * It looks a lot scarier than it really is.... we're doing nothing more
+ * than verifying the doubly-linked list found in p_ysptr and p_osptr, 
+ * and checking it corresponds with the process tree defined by p_cptr and 
+ * p_pptr;
+ */
+void audit_ptree(void)
+{
+	int	i;
+
+	for (i=1 ; i<NR_TASKS ; i++) {
+		if (!task[i])
+			continue;
+		if (bad_task_ptr(task[i]->p_pptr))
+			printk("Warning, pid %d's parent link is bad\n",
+				task[i]->pid);
+		if (bad_task_ptr(task[i]->p_cptr))
+			printk("Warning, pid %d's child link is bad\n",
+				task[i]->pid);
+		if (bad_task_ptr(task[i]->p_ysptr))
+			printk("Warning, pid %d's ys link is bad\n",
+				task[i]->pid);
+		if (bad_task_ptr(task[i]->p_osptr))
+			printk("Warning, pid %d's os link is bad\n",
+				task[i]->pid);
+		if (task[i]->p_pptr == task[i])
+			printk("Warning, pid %d parent link points to self\n",
+				task[i]->pid);
+		if (task[i]->p_cptr == task[i])
+			printk("Warning, pid %d child link points to self\n",
+				task[i]->pid);
+		if (task[i]->p_ysptr == task[i])
+			printk("Warning, pid %d ys link points to self\n",
+				task[i]->pid);
+		if (task[i]->p_osptr == task[i])
+			printk("Warning, pid %d os link points to self\n",
+				task[i]->pid);
+		if (task[i]->p_osptr) {
+			if (task[i]->p_pptr != task[i]->p_osptr->p_pptr)
+				printk(
+			"Warning, pid %d older sibling %d parent is %d\n",
+				task[i]->pid, task[i]->p_osptr->pid,
+				task[i]->p_osptr->p_pptr->pid);
+			if (task[i]->p_osptr->p_ysptr != task[i])
+				printk(
+		"Warning, pid %d older sibling %d has mismatched ys link\n",
+				task[i]->pid, task[i]->p_osptr->pid);
+		}
+		if (task[i]->p_ysptr) {
+			if (task[i]->p_pptr != task[i]->p_ysptr->p_pptr)
+				printk(
+			"Warning, pid %d younger sibling %d parent is %d\n",
+				task[i]->pid, task[i]->p_osptr->pid,
+				task[i]->p_osptr->p_pptr->pid);
+			if (task[i]->p_ysptr->p_osptr != task[i])
+				printk(
+		"Warning, pid %d younger sibling %d has mismatched os link\n",
+				task[i]->pid, task[i]->p_ysptr->pid);
+		}
+		if (task[i]->p_cptr) {
+			if (task[i]->p_cptr->p_pptr != task[i])
+				printk(
+			"Warning, pid %d youngest child %d has mismatched parent link\n",
+				task[i]->pid, task[i]->p_cptr->pid);
+			if (task[i]->p_cptr->p_ysptr)
+				printk(
+			"Warning, pid %d youngest child %d has non-NULL ys link\n",
+				task[i]->pid, task[i]->p_cptr->pid);
+		}
+	}
+}
+#endif /* DEBUG_PROC_TREE */
+
+/*
+ * This checks not only the pgrp, but falls back on the pid if no
+ * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
+ * without this...
+ */
+int session_of_pgrp(int pgrp)
+{
+	struct task_struct *p;
+	int fallback;
+
+	fallback = -1;
+	for_each_task(p) {
+ 		if (p->session <= 0)
+ 			continue;
+		if (p->pgrp == pgrp)
+			return p->session;
+		if (p->pid == pgrp)
+			fallback = p->session;
+	}
+	return fallback;
+}
+
+/*
+ * kill_pg() sends a signal to a process group: this is what the tty
+ * control characters do (^C, ^Z etc)
+ */
+int kill_pg(int pgrp, int sig, int priv)
+{
+	struct task_struct *p;
+	int err,retval = -ESRCH;
+	int found = 0;
+
+	if (sig<0 || sig>32 || pgrp<=0)
+		return -EINVAL;
+	for_each_task(p) {
+		if (p->pgrp == pgrp) {
+			if ((err = send_sig(sig,p,priv)) != 0)
+				retval = err;
+			else
+				found++;
+		}
+	}
+	return(found ? 0 : retval);
+}
+
+/*
+ * kill_sl() sends a signal to the session leader: this is used
+ * to send SIGHUP to the controlling process of a terminal when
+ * the connection is lost.
+ */
+int kill_sl(int sess, int sig, int priv)
+{
+	struct task_struct *p;
+	int err,retval = -ESRCH;
+	int found = 0;
+
+	if (sig<0 || sig>32 || sess<=0)
+		return -EINVAL;
+	for_each_task(p) {
+		if (p->session == sess && p->leader) {
+			if ((err = send_sig(sig,p,priv)) != 0)
+				retval = err;
+			else
+				found++;
+		}
+	}
+	return(found ? 0 : retval);
+}
+
+int kill_proc(int pid, int sig, int priv)
+{
+ 	struct task_struct *p;
+
+	if (sig<0 || sig>32)
+		return -EINVAL;
+	for_each_task(p) {
+		if (p && p->pid == pid)
+			return send_sig(sig,p,priv);
+	}
+	return(-ESRCH);
+}
+
+/*
+ * POSIX specifies that kill(-1,sig) is unspecified, but what we have
+ * is probably wrong.  Should make it like BSD or SYSV.
+ */
+asmlinkage int sys_kill(int pid,int sig)
+{
+	int err, retval = 0, count = 0;
+
+	if (!pid)
+		return(kill_pg(current->pgrp,sig,0));
+	if (pid == -1) {
+		struct task_struct * p;
+		for_each_task(p) {
+			if (p->pid > 1 && p != current) {
+				++count;
+				if ((err = send_sig(sig,p,0)) != -EPERM)
+					retval = err;
+			}
+		}
+		return(count ? retval : -ESRCH);
+	}
+	if (pid < 0) 
+		return(kill_pg(-pid,sig,0));
+	/* Normal kill */
+	return(kill_proc(pid,sig,0));
+}
+
+/*
+ * Determine if a process group is "orphaned", according to the POSIX
+ * definition in 2.2.2.52.  Orphaned process groups are not to be affected
+ * by terminal-generated stop signals.  Newly orphaned process groups are 
+ * to receive a SIGHUP and a SIGCONT.
+ * 
+ * "I ask you, have you ever known what it is to be an orphan?"
+ */
+int is_orphaned_pgrp(int pgrp)
+{
+	struct task_struct *p;
+
+	for_each_task(p) {
+		if ((p->pgrp != pgrp) || 
+		    (p->state == TASK_ZOMBIE) ||
+		    (p->p_pptr->pid == 1))
+			continue;
+		if ((p->p_pptr->pgrp != pgrp) &&
+		    (p->p_pptr->session == p->session))
+			return 0;
+	}
+	return(1);	/* (sighing) "Often!" */
+}
+
+static int has_stopped_jobs(int pgrp)
+{
+	struct task_struct * p;
+
+	for_each_task(p) {
+		if (p->pgrp != pgrp)
+			continue;
+		if (p->state == TASK_STOPPED)
+			return(1);
+	}
+	return(0);
+}
+
+static void forget_original_parent(struct task_struct * father)
+{
+	struct task_struct * p;
+
+	for_each_task(p) {
+		if (p->p_opptr == father)
+			if (task[1])
+				p->p_opptr = task[1];
+			else
+				p->p_opptr = task[0];
+	}
+}
+
+static void exit_mm(void)
+{
+	struct vm_area_struct * mpnt;
+
+	mpnt = current->mm->mmap;
+	current->mm->mmap = NULL;
+	while (mpnt) {
+		struct vm_area_struct * next = mpnt->vm_next;
+		if (mpnt->vm_ops && mpnt->vm_ops->close)
+			mpnt->vm_ops->close(mpnt);
+		if (mpnt->vm_inode)
+			iput(mpnt->vm_inode);
+		kfree(mpnt);
+		mpnt = next;
+	}
+
+	/* forget local segments */
+	__asm__ __volatile__("mov %w0,%%fs ; mov %w0,%%gs ; lldt %w0"
+		: /* no outputs */
+		: "r" (0));
+	current->tss.ldt = 0;
+	if (current->ldt) {
+		void * ldt = current->ldt;
+		current->ldt = NULL;
+		vfree(ldt);
+	}
+
+	free_page_tables(current);
+}
+
+static void exit_files(void)
+{
+	int i;
+
+	for (i=0 ; i<NR_OPEN ; i++)
+		if (current->files->fd[i])
+			sys_close(i);
+}
+
+static void exit_fs(void)
+{
+	iput(current->fs->pwd);
+	current->fs->pwd = NULL;
+	iput(current->fs->root);
+	current->fs->root = NULL;
+}
+
+NORET_TYPE void do_exit(long code)
+{
+	struct task_struct *p;
+
+	if (intr_count) {
+		printk("Aiee, killing interrupt handler\n");
+		intr_count = 0;
+	}
+fake_volatile:
+	if (current->semundo)
+		sem_exit();
+	exit_mm();
+	exit_files();
+	exit_fs();
+	forget_original_parent(current);
+	/* 
+	 * Check to see if any process groups have become orphaned
+	 * as a result of our exiting, and if they have any stopped
+	 * jobs, send them a SIGUP and then a SIGCONT.  (POSIX 3.2.2.2)
+	 *
+	 * Case i: Our father is in a different pgrp than we are
+	 * and we were the only connection outside, so our pgrp
+	 * is about to become orphaned.
+ 	 */
+	if ((current->p_pptr->pgrp != current->pgrp) &&
+	    (current->p_pptr->session == current->session) &&
+	    is_orphaned_pgrp(current->pgrp) &&
+	    has_stopped_jobs(current->pgrp)) {
+		kill_pg(current->pgrp,SIGHUP,1);
+		kill_pg(current->pgrp,SIGCONT,1);
+	}
+	/* Let father know we died */
+	notify_parent(current);
+	
+	/*
+	 * This loop does two things:
+	 * 
+  	 * A.  Make init inherit all the child processes
+	 * B.  Check to see if any process groups have become orphaned
+	 *	as a result of our exiting, and if they have any stopped
+	 *	jobs, send them a SIGHUP and then a SIGCONT.  (POSIX 3.2.2.2)
+	 */
+	while ((p = current->p_cptr) != NULL) {
+		current->p_cptr = p->p_osptr;
+		p->p_ysptr = NULL;
+		p->flags &= ~(PF_PTRACED|PF_TRACESYS);
+		if (task[1] && task[1] != current)
+			p->p_pptr = task[1];
+		else
+			p->p_pptr = task[0];
+		p->p_osptr = p->p_pptr->p_cptr;
+		p->p_osptr->p_ysptr = p;
+		p->p_pptr->p_cptr = p;
+		if (p->state == TASK_ZOMBIE)
+			notify_parent(p);
+		/*
+		 * process group orphan check
+		 * Case ii: Our child is in a different pgrp 
+		 * than we are, and it was the only connection
+		 * outside, so the child pgrp is now orphaned.
+		 */
+		if ((p->pgrp != current->pgrp) &&
+		    (p->session == current->session) &&
+		    is_orphaned_pgrp(p->pgrp) &&
+		    has_stopped_jobs(p->pgrp)) {
+			kill_pg(p->pgrp,SIGHUP,1);
+			kill_pg(p->pgrp,SIGCONT,1);
+		}
+	}
+	if (current->leader)
+		disassociate_ctty(1);
+	if (last_task_used_math == current)
+		last_task_used_math = NULL;
+	current->state = TASK_ZOMBIE;
+	current->exit_code = code;
+	current->mm->rss = 0;
+#ifdef DEBUG_PROC_TREE
+	audit_ptree();
+#endif
+	if (current->exec_domain && current->exec_domain->use_count)
+		(*current->exec_domain->use_count)--;
+	if (current->binfmt && current->binfmt->use_count)
+		(*current->binfmt->use_count)--;
+	schedule();
+/*
+ * In order to get rid of the "volatile function does return" message
+ * I did this little loop that confuses gcc to think do_exit really
+ * is volatile. In fact it's schedule() that is volatile in some
+ * circumstances: when current->state = ZOMBIE, schedule() never
+ * returns.
+ *
+ * In fact the natural way to do all this is to have the label and the
+ * goto right after each other, but I put the fake_volatile label at
+ * the start of the function just in case something /really/ bad
+ * happens, and the schedule returns. This way we can try again. I'm
+ * not paranoid: it's just that everybody is out to get me.
+ */
+	goto fake_volatile;
+}
+
+asmlinkage int sys_exit(int error_code)
+{
+	do_exit((error_code&0xff)<<8);
+}
+
+asmlinkage int sys_wait4(pid_t pid,unsigned long * stat_addr, int options, struct rusage * ru)
+{
+	int flag, retval;
+	struct wait_queue wait = { current, NULL };
+	struct task_struct *p;
+
+	if (stat_addr) {
+		flag = verify_area(VERIFY_WRITE, stat_addr, 4);
+		if (flag)
+			return flag;
+	}
+	add_wait_queue(&current->wait_chldexit,&wait);
+repeat:
+	flag=0;
+ 	for (p = current->p_cptr ; p ; p = p->p_osptr) {
+		if (pid>0) {
+			if (p->pid != pid)
+				continue;
+		} else if (!pid) {
+			if (p->pgrp != current->pgrp)
+				continue;
+		} else if (pid != -1) {
+			if (p->pgrp != -pid)
+				continue;
+		}
+		/* wait for cloned processes iff the __WCLONE flag is set */
+		if ((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
+			continue;
+		flag = 1;
+		switch (p->state) {
+			case TASK_STOPPED:
+				if (!p->exit_code)
+					continue;
+				if (!(options & WUNTRACED) && !(p->flags & PF_PTRACED))
+					continue;
+				if (stat_addr)
+					put_fs_long((p->exit_code << 8) | 0x7f,
+						stat_addr);
+				p->exit_code = 0;
+				if (ru != NULL)
+					getrusage(p, RUSAGE_BOTH, ru);
+				retval = p->pid;
+				goto end_wait4;
+			case TASK_ZOMBIE:
+				current->cutime += p->utime + p->cutime;
+				current->cstime += p->stime + p->cstime;
+				current->mm->cmin_flt += p->mm->min_flt + p->mm->cmin_flt;
+				current->mm->cmaj_flt += p->mm->maj_flt + p->mm->cmaj_flt;
+				if (ru != NULL)
+					getrusage(p, RUSAGE_BOTH, ru);
+				flag = p->pid;
+				if (stat_addr)
+					put_fs_long(p->exit_code, stat_addr);
+				if (p->p_opptr != p->p_pptr) {
+					REMOVE_LINKS(p);
+					p->p_pptr = p->p_opptr;
+					SET_LINKS(p);
+					notify_parent(p);
+				} else
+					release(p);
+#ifdef DEBUG_PROC_TREE
+				audit_ptree();
+#endif
+				retval = flag;
+				goto end_wait4;
+			default:
+				continue;
+		}
+	}
+	if (flag) {
+		retval = 0;
+		if (options & WNOHANG)
+			goto end_wait4;
+		current->state=TASK_INTERRUPTIBLE;
+		schedule();
+		current->signal &= ~(1<<(SIGCHLD-1));
+		retval = -ERESTARTSYS;
+		if (current->signal & ~current->blocked)
+			goto end_wait4;
+		goto repeat;
+	}
+	retval = -ECHILD;
+end_wait4:
+	remove_wait_queue(&current->wait_chldexit,&wait);
+	return retval;
+}
+
+/*
+ * sys_waitpid() remains for compatibility. waitpid() should be
+ * implemented by calling sys_wait4() from libc.a.
+ */
+asmlinkage int sys_waitpid(pid_t pid,unsigned long * stat_addr, int options)
+{
+	return sys_wait4(pid, stat_addr, options, NULL);
+}