Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 717 insertions, 0 deletions

diff --git a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c
new file mode 100644
index 00000000000..b2f17640cef
--- /dev/null
+++ b/arch/i386/kernel/ptrace.c
@@ -0,0 +1,717 @@
+/* ptrace.c */
+/* By Ross Biro 1/23/92 */
+/*
+ * Pentium III FXSR, SSE support
+ *	Gareth Hughes <gareth@valinux.com>, May 2000
+ */
+
+#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 <linux/security.h>
+#include <linux/audit.h>
+#include <linux/seccomp.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+#include <asm/processor.h>
+#include <asm/i387.h>
+#include <asm/debugreg.h>
+#include <asm/ldt.h>
+#include <asm/desc.h>
+
+/*
+ * does not yet catch signals sent when the child dies.
+ * in exit.c or in signal.c.
+ */
+
+/* determines which flags the user has access to. */
+/* 1 = access 0 = no access */
+#define FLAG_MASK 0x00044dd5
+
+/* set's the trap flag. */
+#define TRAP_FLAG 0x100
+
+/*
+ * Offset of eflags on child stack..
+ */
+#define EFL_OFFSET ((EFL-2)*4-sizeof(struct pt_regs))
+
+static inline struct pt_regs *get_child_regs(struct task_struct *task)
+{
+	void *stack_top = (void *)task->thread.esp0;
+	return stack_top - sizeof(struct pt_regs);
+}
+
+/*
+ * this routine will get a word off of the processes privileged stack. 
+ * the offset is how far from the base addr as stored in the TSS.  
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */   
+static inline int get_stack_long(struct task_struct *task, int offset)
+{
+	unsigned char *stack;
+
+	stack = (unsigned char *)task->thread.esp0;
+	stack += offset;
+	return (*((int *)stack));
+}
+
+/*
+ * this routine will put a word on the processes privileged stack. 
+ * the offset is how far from the base addr as stored in the TSS.  
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline int put_stack_long(struct task_struct *task, int offset,
+	unsigned long data)
+{
+	unsigned char * stack;
+
+	stack = (unsigned char *) task->thread.esp0;
+	stack += offset;
+	*(unsigned long *) stack = data;
+	return 0;
+}
+
+static int putreg(struct task_struct *child,
+	unsigned long regno, unsigned long value)
+{
+	switch (regno >> 2) {
+		case FS:
+			if (value && (value & 3) != 3)
+				return -EIO;
+			child->thread.fs = value;
+			return 0;
+		case GS:
+			if (value && (value & 3) != 3)
+				return -EIO;
+			child->thread.gs = value;
+			return 0;
+		case DS:
+		case ES:
+			if (value && (value & 3) != 3)
+				return -EIO;
+			value &= 0xffff;
+			break;
+		case SS:
+		case CS:
+			if ((value & 3) != 3)
+				return -EIO;
+			value &= 0xffff;
+			break;
+		case EFL:
+			value &= FLAG_MASK;
+			value |= get_stack_long(child, EFL_OFFSET) & ~FLAG_MASK;
+			break;
+	}
+	if (regno > GS*4)
+		regno -= 2*4;
+	put_stack_long(child, regno - sizeof(struct pt_regs), value);
+	return 0;
+}
+
+static unsigned long getreg(struct task_struct *child,
+	unsigned long regno)
+{
+	unsigned long retval = ~0UL;
+
+	switch (regno >> 2) {
+		case FS:
+			retval = child->thread.fs;
+			break;
+		case GS:
+			retval = child->thread.gs;
+			break;
+		case DS:
+		case ES:
+		case SS:
+		case CS:
+			retval = 0xffff;
+			/* fall through */
+		default:
+			if (regno > GS*4)
+				regno -= 2*4;
+			regno = regno - sizeof(struct pt_regs);
+			retval &= get_stack_long(child, regno);
+	}
+	return retval;
+}
+
+#define LDT_SEGMENT 4
+
+static unsigned long convert_eip_to_linear(struct task_struct *child, struct pt_regs *regs)
+{
+	unsigned long addr, seg;
+
+	addr = regs->eip;
+	seg = regs->xcs & 0xffff;
+	if (regs->eflags & VM_MASK) {
+		addr = (addr & 0xffff) + (seg << 4);
+		return addr;
+	}
+
+	/*
+	 * We'll assume that the code segments in the GDT
+	 * are all zero-based. That is largely true: the
+	 * TLS segments are used for data, and the PNPBIOS
+	 * and APM bios ones we just ignore here.
+	 */
+	if (seg & LDT_SEGMENT) {
+		u32 *desc;
+		unsigned long base;
+
+		down(&child->mm->context.sem);
+		desc = child->mm->context.ldt + (seg & ~7);
+		base = (desc[0] >> 16) | ((desc[1] & 0xff) << 16) | (desc[1] & 0xff000000);
+
+		/* 16-bit code segment? */
+		if (!((desc[1] >> 22) & 1))
+			addr &= 0xffff;
+		addr += base;
+		up(&child->mm->context.sem);
+	}
+	return addr;
+}
+
+static inline int is_at_popf(struct task_struct *child, struct pt_regs *regs)
+{
+	int i, copied;
+	unsigned char opcode[16];
+	unsigned long addr = convert_eip_to_linear(child, regs);
+
+	copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
+	for (i = 0; i < copied; i++) {
+		switch (opcode[i]) {
+		/* popf */
+		case 0x9d:
+			return 1;
+		/* opcode and address size prefixes */
+		case 0x66: case 0x67:
+			continue;
+		/* irrelevant prefixes (segment overrides and repeats) */
+		case 0x26: case 0x2e:
+		case 0x36: case 0x3e:
+		case 0x64: case 0x65:
+		case 0xf0: case 0xf2: case 0xf3:
+			continue;
+
+		/*
+		 * pushf: NOTE! We should probably not let
+		 * the user see the TF bit being set. But
+		 * it's more pain than it's worth to avoid
+		 * it, and a debugger could emulate this
+		 * all in user space if it _really_ cares.
+		 */
+		case 0x9c:
+		default:
+			return 0;
+		}
+	}
+	return 0;
+}
+
+static void set_singlestep(struct task_struct *child)
+{
+	struct pt_regs *regs = get_child_regs(child);
+
+	/*
+	 * Always set TIF_SINGLESTEP - this guarantees that 
+	 * we single-step system calls etc..  This will also
+	 * cause us to set TF when returning to user mode.
+	 */
+	set_tsk_thread_flag(child, TIF_SINGLESTEP);
+
+	/*
+	 * If TF was already set, don't do anything else
+	 */
+	if (regs->eflags & TRAP_FLAG)
+		return;
+
+	/* Set TF on the kernel stack.. */
+	regs->eflags |= TRAP_FLAG;
+
+	/*
+	 * ..but if TF is changed by the instruction we will trace,
+	 * don't mark it as being "us" that set it, so that we
+	 * won't clear it by hand later.
+	 */
+	if (is_at_popf(child, regs))
+		return;
+	
+	child->ptrace |= PT_DTRACE;
+}
+
+static void clear_singlestep(struct task_struct *child)
+{
+	/* Always clear TIF_SINGLESTEP... */
+	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+
+	/* But touch TF only if it was set by us.. */
+	if (child->ptrace & PT_DTRACE) {
+		struct pt_regs *regs = get_child_regs(child);
+		regs->eflags &= ~TRAP_FLAG;
+		child->ptrace &= ~PT_DTRACE;
+	}
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ *
+ * Make sure the single step bit is not set.
+ */
+void ptrace_disable(struct task_struct *child)
+{ 
+	clear_singlestep(child);
+}
+
+/*
+ * Perform get_thread_area on behalf of the traced child.
+ */
+static int
+ptrace_get_thread_area(struct task_struct *child,
+		       int idx, struct user_desc __user *user_desc)
+{
+	struct user_desc info;
+	struct desc_struct *desc;
+
+/*
+ * Get the current Thread-Local Storage area:
+ */
+
+#define GET_BASE(desc) ( \
+	(((desc)->a >> 16) & 0x0000ffff) | \
+	(((desc)->b << 16) & 0x00ff0000) | \
+	( (desc)->b        & 0xff000000)   )
+
+#define GET_LIMIT(desc) ( \
+	((desc)->a & 0x0ffff) | \
+	 ((desc)->b & 0xf0000) )
+
+#define GET_32BIT(desc)		(((desc)->b >> 22) & 1)
+#define GET_CONTENTS(desc)	(((desc)->b >> 10) & 3)
+#define GET_WRITABLE(desc)	(((desc)->b >>  9) & 1)
+#define GET_LIMIT_PAGES(desc)	(((desc)->b >> 23) & 1)
+#define GET_PRESENT(desc)	(((desc)->b >> 15) & 1)
+#define GET_USEABLE(desc)	(((desc)->b >> 20) & 1)
+
+	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
+		return -EINVAL;
+
+	desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
+
+	info.entry_number = idx;
+	info.base_addr = GET_BASE(desc);
+	info.limit = GET_LIMIT(desc);
+	info.seg_32bit = GET_32BIT(desc);
+	info.contents = GET_CONTENTS(desc);
+	info.read_exec_only = !GET_WRITABLE(desc);
+	info.limit_in_pages = GET_LIMIT_PAGES(desc);
+	info.seg_not_present = !GET_PRESENT(desc);
+	info.useable = GET_USEABLE(desc);
+
+	if (copy_to_user(user_desc, &info, sizeof(info)))
+		return -EFAULT;
+
+	return 0;
+}
+
+/*
+ * Perform set_thread_area on behalf of the traced child.
+ */
+static int
+ptrace_set_thread_area(struct task_struct *child,
+		       int idx, struct user_desc __user *user_desc)
+{
+	struct user_desc info;
+	struct desc_struct *desc;
+
+	if (copy_from_user(&info, user_desc, sizeof(info)))
+		return -EFAULT;
+
+	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
+		return -EINVAL;
+
+	desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
+	if (LDT_empty(&info)) {
+		desc->a = 0;
+		desc->b = 0;
+	} else {
+		desc->a = LDT_entry_a(&info);
+		desc->b = LDT_entry_b(&info);
+	}
+
+	return 0;
+}
+
+asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
+{
+	struct task_struct *child;
+	struct user * dummy = NULL;
+	int i, ret;
+	unsigned long __user *datap = (unsigned long __user *)data;
+
+	lock_kernel();
+	ret = -EPERM;
+	if (request == PTRACE_TRACEME) {
+		/* are we already being traced? */
+		if (current->ptrace & PT_PTRACED)
+			goto out;
+		ret = security_ptrace(current->parent, current);
+		if (ret)
+			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)		/* you may not mess with init */
+		goto out_tsk;
+
+	if (request == PTRACE_ATTACH) {
+		ret = ptrace_attach(child);
+		goto out_tsk;
+	}
+
+	ret = ptrace_check_attach(child, request == PTRACE_KILL);
+	if (ret < 0)
+		goto out_tsk;
+
+	switch (request) {
+	/* when I and D space are separate, these will need to be fixed. */
+	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))
+			break;
+		ret = put_user(tmp, datap);
+		break;
+	}
+
+	/* read the word at location addr in the USER area. */
+	case PTRACE_PEEKUSR: {
+		unsigned long tmp;
+
+		ret = -EIO;
+		if ((addr & 3) || addr < 0 || 
+		    addr > sizeof(struct user) - 3)
+			break;
+
+		tmp = 0;  /* Default return condition */
+		if(addr < FRAME_SIZE*sizeof(long))
+			tmp = getreg(child, addr);
+		if(addr >= (long) &dummy->u_debugreg[0] &&
+		   addr <= (long) &dummy->u_debugreg[7]){
+			addr -= (long) &dummy->u_debugreg[0];
+			addr = addr >> 2;
+			tmp = child->thread.debugreg[addr];
+		}
+		ret = put_user(tmp, datap);
+		break;
+	}
+
+	/* 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))
+			break;
+		ret = -EIO;
+		break;
+
+	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
+		ret = -EIO;
+		if ((addr & 3) || addr < 0 || 
+		    addr > sizeof(struct user) - 3)
+			break;
+
+		if (addr < FRAME_SIZE*sizeof(long)) {
+			ret = putreg(child, addr, data);
+			break;
+		}
+		/* We need to be very careful here.  We implicitly
+		   want to modify a portion of the task_struct, and we
+		   have to be selective about what portions we allow someone
+		   to modify. */
+
+		  ret = -EIO;
+		  if(addr >= (long) &dummy->u_debugreg[0] &&
+		     addr <= (long) &dummy->u_debugreg[7]){
+
+			  if(addr == (long) &dummy->u_debugreg[4]) break;
+			  if(addr == (long) &dummy->u_debugreg[5]) break;
+			  if(addr < (long) &dummy->u_debugreg[4] &&
+			     ((unsigned long) data) >= TASK_SIZE-3) break;
+			  
+			  /* Sanity-check data. Take one half-byte at once with
+			   * check = (val >> (16 + 4*i)) & 0xf. It contains the
+			   * R/Wi and LENi bits; bits 0 and 1 are R/Wi, and bits
+			   * 2 and 3 are LENi. Given a list of invalid values,
+			   * we do mask |= 1 << invalid_value, so that
+			   * (mask >> check) & 1 is a correct test for invalid
+			   * values.
+			   *
+			   * R/Wi contains the type of the breakpoint /
+			   * watchpoint, LENi contains the length of the watched
+			   * data in the watchpoint case.
+			   *
+			   * The invalid values are:
+			   * - LENi == 0x10 (undefined), so mask |= 0x0f00.
+			   * - R/Wi == 0x10 (break on I/O reads or writes), so
+			   *   mask |= 0x4444.
+			   * - R/Wi == 0x00 && LENi != 0x00, so we have mask |=
+			   *   0x1110.
+			   *
+			   * Finally, mask = 0x0f00 | 0x4444 | 0x1110 == 0x5f54.
+			   *
+			   * See the Intel Manual "System Programming Guide",
+			   * 15.2.4
+			   *
+			   * Note that LENi == 0x10 is defined on x86_64 in long
+			   * mode (i.e. even for 32-bit userspace software, but
+			   * 64-bit kernel), so the x86_64 mask value is 0x5454.
+			   * See the AMD manual no. 24593 (AMD64 System
+			   * Programming)*/
+
+			  if(addr == (long) &dummy->u_debugreg[7]) {
+				  data &= ~DR_CONTROL_RESERVED;
+				  for(i=0; i<4; i++)
+					  if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
+						  goto out_tsk;
+			  }
+
+			  addr -= (long) &dummy->u_debugreg;
+			  addr = addr >> 2;
+			  child->thread.debugreg[addr] = data;
+			  ret = 0;
+		  }
+		  break;
+
+	case PTRACE_SYSCALL:	/* continue and stop at next (return from) syscall */
+	case PTRACE_CONT:	/* restart after signal. */
+		ret = -EIO;
+		if ((unsigned long) data > _NSIG)
+			break;
+		if (request == PTRACE_SYSCALL) {
+			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+		}
+		else {
+			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+		}
+		child->exit_code = data;
+		/* make sure the single step bit is not set. */
+		clear_singlestep(child);
+		wake_up_process(child);
+		ret = 0;
+		break;
+
+/*
+ * 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.
+ */
+	case PTRACE_KILL:
+		ret = 0;
+		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
+			break;
+		child->exit_code = SIGKILL;
+		/* make sure the single step bit is not set. */
+		clear_singlestep(child);
+		wake_up_process(child);
+		break;
+
+	case PTRACE_SINGLESTEP:	/* set the trap flag. */
+		ret = -EIO;
+		if ((unsigned long) data > _NSIG)
+			break;
+		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+		set_singlestep(child);
+		child->exit_code = data;
+		/* give it a chance to run. */
+		wake_up_process(child);
+		ret = 0;
+		break;
+
+	case PTRACE_DETACH:
+		/* detach a process that was attached. */
+		ret = ptrace_detach(child, data);
+		break;
+
+	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
+	  	if (!access_ok(VERIFY_WRITE, datap, FRAME_SIZE*sizeof(long))) {
+			ret = -EIO;
+			break;
+		}
+		for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
+			__put_user(getreg(child, i), datap);
+			datap++;
+		}
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
+		unsigned long tmp;
+	  	if (!access_ok(VERIFY_READ, datap, FRAME_SIZE*sizeof(long))) {
+			ret = -EIO;
+			break;
+		}
+		for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
+			__get_user(tmp, datap);
+			putreg(child, i, tmp);
+			datap++;
+		}
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_GETFPREGS: { /* Get the child FPU state. */
+		if (!access_ok(VERIFY_WRITE, datap,
+			       sizeof(struct user_i387_struct))) {
+			ret = -EIO;
+			break;
+		}
+		ret = 0;
+		if (!tsk_used_math(child))
+			init_fpu(child);
+		get_fpregs((struct user_i387_struct __user *)data, child);
+		break;
+	}
+
+	case PTRACE_SETFPREGS: { /* Set the child FPU state. */
+		if (!access_ok(VERIFY_READ, datap,
+			       sizeof(struct user_i387_struct))) {
+			ret = -EIO;
+			break;
+		}
+		set_stopped_child_used_math(child);
+		set_fpregs(child, (struct user_i387_struct __user *)data);
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_GETFPXREGS: { /* Get the child extended FPU state. */
+		if (!access_ok(VERIFY_WRITE, datap,
+			       sizeof(struct user_fxsr_struct))) {
+			ret = -EIO;
+			break;
+		}
+		if (!tsk_used_math(child))
+			init_fpu(child);
+		ret = get_fpxregs((struct user_fxsr_struct __user *)data, child);
+		break;
+	}
+
+	case PTRACE_SETFPXREGS: { /* Set the child extended FPU state. */
+		if (!access_ok(VERIFY_READ, datap,
+			       sizeof(struct user_fxsr_struct))) {
+			ret = -EIO;
+			break;
+		}
+		set_stopped_child_used_math(child);
+		ret = set_fpxregs(child, (struct user_fxsr_struct __user *)data);
+		break;
+	}
+
+	case PTRACE_GET_THREAD_AREA:
+		ret = ptrace_get_thread_area(child, addr,
+					(struct user_desc __user *) data);
+		break;
+
+	case PTRACE_SET_THREAD_AREA:
+		ret = ptrace_set_thread_area(child, addr,
+					(struct user_desc __user *) data);
+		break;
+
+	default:
+		ret = ptrace_request(child, request, addr, data);
+		break;
+	}
+out_tsk:
+	put_task_struct(child);
+out:
+	unlock_kernel();
+	return ret;
+}
+
+void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
+{
+	struct siginfo info;
+
+	tsk->thread.trap_no = 1;
+	tsk->thread.error_code = error_code;
+
+	memset(&info, 0, sizeof(info));
+	info.si_signo = SIGTRAP;
+	info.si_code = TRAP_BRKPT;
+
+	/* User-mode eip? */
+	info.si_addr = user_mode(regs) ? (void __user *) regs->eip : NULL;
+
+	/* Send us the fakey SIGTRAP */
+	force_sig_info(SIGTRAP, &info, tsk);
+}
+
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
+ */
+__attribute__((regparm(3)))
+void do_syscall_trace(struct pt_regs *regs, int entryexit)
+{
+	/* do the secure computing check first */
+	secure_computing(regs->orig_eax);
+
+	if (unlikely(current->audit_context)) {
+		if (!entryexit)
+			audit_syscall_entry(current, regs->orig_eax,
+					    regs->ebx, regs->ecx,
+					    regs->edx, regs->esi);
+		else
+			audit_syscall_exit(current, regs->eax);
+	}
+
+	if (!(current->ptrace & PT_PTRACED))
+		return;
+
+	/* Fake a debug trap */
+	if (test_thread_flag(TIF_SINGLESTEP))
+		send_sigtrap(current, regs, 0);
+
+	if (!test_thread_flag(TIF_SYSCALL_TRACE))
+		return;
+
+	/* the 0x80 provides a way for the tracing parent to distinguish
+	   between a syscall stop and SIGTRAP delivery */
+	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
+
+	/*
+	 * 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;
+	}
+}