patch-2.4.0-test12 linux/arch/parisc/kernel/ptrace.c

• Lines: 306
• Date: Tue Dec 5 12:29:39 2000
• Orig file: v2.4.0-test11/linux/arch/parisc/kernel/ptrace.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.0-test11/linux/arch/parisc/kernel/ptrace.c linux/arch/parisc/kernel/ptrace.c
@@ -0,0 +1,305 @@
+/*
+ * Kernel support for the ptrace() and syscall tracing interfaces.
+ *
+ * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
+ * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
+ * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+#include <asm/processor.h>
+#include <asm/offset.h>
+
+/* These are used in entry.S, syscall_restore_rfi.  We need to record the
+ * current stepping mode somewhere other than in PSW, because there is no
+ * concept of saving and restoring the users PSW over a syscall.  We choose
+ * to use these two bits in task->ptrace.  These bits must not clash with
+ * any PT_* defined in include/linux/sched.h, and must match with the bit
+ * tests in entry.S
+ */
+#define PT_SINGLESTEP	0x10000
+#define PT_BLOCKSTEP	0x20000
+
+long sys_ptrace(long request, pid_t pid, long addr, long data)
+{
+	struct task_struct *child;
+	long ret;
+
+	lock_kernel();
+	ret = -EPERM;
+	if (request == PTRACE_TRACEME) {
+		/* are we already being traced? */
+		if (current->ptrace & PT_PTRACED)
+			goto out;
+		/* set the ptrace bit in the process flags. */
+		current->ptrace |= PT_PTRACED;
+		ret = 0;
+		goto out;
+	}
+
+	ret = -ESRCH;
+	read_lock(&tasklist_lock);
+	child = find_task_by_pid(pid);
+	if (child)
+		get_task_struct(child);
+	read_unlock(&tasklist_lock);
+	if (!child)
+		goto out;
+	ret = -EPERM;
+	if (pid == 1)		/* no messing around with init! */
+		goto out_tsk;
+
+	if (request == PTRACE_ATTACH) {
+		if (child == current)
+			goto out_tsk;
+		if ((!child->dumpable ||
+		    (current->uid != child->euid) ||
+		    (current->uid != child->suid) ||
+		    (current->uid != child->uid) ||
+	 	    (current->gid != child->egid) ||
+	 	    (current->gid != child->sgid) ||
+	 	    (!cap_issubset(child->cap_permitted, current->cap_permitted)) ||
+	 	    (current->gid != child->gid)) && !capable(CAP_SYS_PTRACE))
+			goto out_tsk;
+		/* the same process cannot be attached many times */
+		if (child->ptrace & PT_PTRACED)
+			goto out_tsk;
+		child->ptrace |= PT_PTRACED;
+		if (child->p_pptr != current) {
+			unsigned long flags;
+
+			write_lock_irqsave(&tasklist_lock, flags);
+			REMOVE_LINKS(child);
+			child->p_pptr = current;
+			SET_LINKS(child);
+			write_unlock_irqrestore(&tasklist_lock, flags);
+		}
+		send_sig(SIGSTOP, child, 1);
+		ret = 0;
+		goto out_tsk;
+	}
+	ret = -ESRCH;
+	if (!(child->ptrace & PT_PTRACED))
+		goto out_tsk;
+	if (child->state != TASK_STOPPED) {
+		if (request != PTRACE_KILL)
+			goto out_tsk;
+	}
+	if (child->p_pptr != current)
+		goto out_tsk;
+
+	switch (request) {
+	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
+	case PTRACE_PEEKDATA: {
+		unsigned long tmp;
+		int copied;
+
+		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
+		ret = -EIO;
+		if (copied != sizeof(tmp))
+			goto out_tsk;
+		ret = put_user(tmp,(unsigned long *) data);
+		goto out_tsk;
+	}
+
+	/* when I and D space are separate, this will have to be fixed. */
+	case PTRACE_POKETEXT: /* write the word at location addr. */
+	case PTRACE_POKEDATA:
+		ret = 0;
+		if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
+			goto out_tsk;
+		ret = -EIO;
+		goto out_tsk;
+
+	/* Read the word at location addr in the USER area.  This will need
+	   to change when the kernel no longer saves all regs on a syscall. */
+	case PTRACE_PEEKUSR: {
+		unsigned long tmp;
+
+		ret = -EIO;
+		if ((addr & 3) || (unsigned long) addr >= sizeof(struct pt_regs))
+			goto out_tsk;
+
+		tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
+		ret = put_user(tmp, (unsigned long *) data);
+		goto out_tsk;
+	}
+
+	/* Write the word at location addr in the USER area.  This will need
+	   to change when the kernel no longer saves all regs on a syscall.
+	   FIXME.  There is a problem at the moment in that r3-r18 are only
+	   saved if the process is ptraced on syscall entry, and even then
+	   those values are overwritten by actual register values on syscall
+	   exit. */
+	case PTRACE_POKEUSR:
+		ret = -EIO;
+		if ((addr & 3) || (unsigned long) addr >= sizeof(struct pt_regs))
+			goto out_tsk;
+		/* XXX This test probably needs adjusting.  We probably want to
+		 * allow writes to some bits of PSW, and may want to block writes
+		 * to (some) space registers.  Some register values written here
+		 * may be ignored in entry.S:syscall_restore_rfi; e.g. iaoq is
+		 * written with r31/r31+4, and not with the values in pt_regs.
+		 */
+		/* Allow writing of gr1-gr31, fr*, sr*, iasq*, iaoq*, sar */
+		if (addr == PT_PSW || (addr > PT_IAOQ1 && addr != PT_SAR))
+			goto out_tsk;
+
+		*(unsigned long *) ((char *) task_regs(child) + addr) = data;
+		ret = 0;
+		goto out_tsk;
+
+	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
+	case PTRACE_CONT:
+		ret = -EIO;
+		if ((unsigned long) data > _NSIG)
+			goto out_tsk;
+		child->ptrace &= ~(PT_SINGLESTEP|PT_BLOCKSTEP);
+		if (request == PTRACE_SYSCALL)
+			child->ptrace |= PT_TRACESYS;
+		else
+			child->ptrace &= ~PT_TRACESYS;
+		child->exit_code = data;
+		goto out_wake_notrap;
+
+	case PTRACE_KILL:
+		/*
+		 * make the child exit.  Best I can do is send it a
+		 * sigkill.  perhaps it should be put in the status
+		 * that it wants to exit.
+		 */
+		if (child->state == TASK_ZOMBIE)	/* already dead */
+			goto out_tsk;
+		child->exit_code = SIGKILL;
+		goto out_wake_notrap;
+
+	case PTRACE_SINGLEBLOCK:
+		ret = -EIO;
+		if ((unsigned long) data > _NSIG)
+			goto out_tsk;
+		child->ptrace &= ~(PT_TRACESYS|PT_SINGLESTEP);
+		child->ptrace |= PT_BLOCKSTEP;
+		child->exit_code = data;
+
+		/* Enable taken branch trap. */
+		pa_psw(child)->r = 0;
+		pa_psw(child)->t = 1;
+		pa_psw(child)->h = 0;
+		pa_psw(child)->l = 0;
+		goto out_wake;
+
+	case PTRACE_SINGLESTEP:
+		ret = -EIO;
+		if ((unsigned long) data > _NSIG)
+			goto out_tsk;
+		child->ptrace &= ~(PT_TRACESYS|PT_BLOCKSTEP);
+		child->ptrace |= PT_SINGLESTEP;
+		child->exit_code = data;
+
+		if (pa_psw(child)->n) {
+			struct siginfo si;
+
+			/* Nullified, just crank over the queue. */
+			task_regs(child)->iaoq[0] = task_regs(child)->iaoq[1];
+			task_regs(child)->iasq[0] = task_regs(child)->iasq[1];
+			task_regs(child)->iaoq[1] = task_regs(child)->iaoq[0] + 4;
+			pa_psw(child)->n = 0;
+			pa_psw(child)->x = 0;
+			pa_psw(child)->y = 0;
+			pa_psw(child)->z = 0;
+			pa_psw(child)->b = 0;
+			pa_psw(child)->r = 0;
+			pa_psw(child)->t = 0;
+			pa_psw(child)->h = 0;
+			pa_psw(child)->l = 0;
+			/* Don't wake up the child, but let the
+			   parent know something happened. */
+			si.si_code = TRAP_TRACE;
+			si.si_addr = (void *) (task_regs(child)->iaoq[0] & ~3);
+			si.si_signo = SIGTRAP;
+			si.si_errno = 0;
+			force_sig_info(SIGTRAP, &si, child);
+			//notify_parent(child, SIGCHLD);
+			//ret = 0;
+			goto out_wake;
+		}
+
+		/* Enable recovery counter traps.  The recovery counter
+		 * itself will be set to zero on a task switch.  If the
+		 * task is suspended on a syscall then the syscall return
+		 * path will overwrite the recovery counter with a suitable
+		 * value such that it traps once back in user space.  We
+		 * disable interrupts in the childs PSW here also, to avoid
+		 * interrupts while the recovery counter is decrementing.
+		 */
+		pa_psw(child)->r = 1;
+		pa_psw(child)->t = 0;
+		pa_psw(child)->h = 0;
+		pa_psw(child)->l = 0;
+		/* give it a chance to run. */
+		goto out_wake;
+
+	case PTRACE_DETACH:
+		ret = -EIO;
+		if ((unsigned long) data > _NSIG)
+			goto out_tsk;
+		child->ptrace &= ~(PT_PTRACED|PT_TRACESYS|PT_SINGLESTEP|PT_BLOCKSTEP);
+		child->exit_code = data;
+		write_lock_irq(&tasklist_lock);
+		REMOVE_LINKS(child);
+		child->p_pptr = child->p_opptr;
+		SET_LINKS(child);
+		write_unlock_irq(&tasklist_lock);
+		goto out_wake_notrap;
+
+	default:
+		ret = -EIO;
+		goto out_tsk;
+	}
+
+out_wake_notrap:
+	/* make sure the trap bits are not set */
+	pa_psw(child)->r = 0;
+	pa_psw(child)->t = 0;
+	pa_psw(child)->h = 0;
+	pa_psw(child)->l = 0;
+out_wake:
+	wake_up_process(child);
+	ret = 0;
+out_tsk:
+	free_task_struct(child);
+out:
+	unlock_kernel();
+	return ret;
+}
+
+void syscall_trace(void)
+{
+	if ((current->ptrace & (PT_PTRACED|PT_TRACESYS)) !=
+			(PT_PTRACED|PT_TRACESYS))
+		return;
+	current->exit_code = SIGTRAP;
+	current->state = TASK_STOPPED;
+	notify_parent(current, SIGCHLD);
+	schedule();
+	/*
+	 * this isn't the same as continuing with a signal, but it will do
+	 * for normal use.  strace only continues with a signal if the
+	 * stopping signal is not SIGTRAP.  -brl
+	 */
+	if (current->exit_code) {
+		send_sig(current->exit_code, current, 1);
+		current->exit_code = 0;
+	}
+}