trclib.c

VXWORKS源代码

/* trcLib.c - i80x86 stack trace library */

/* Copyright 1984-2001 Wind River Systems, Inc. */
#include "copyright_wrs.h"

/*
modification history
--------------------
01f,16jan02,pai  replaced obsolete symFindByValue (_func_symFindByValue) with
                 symByValueFind.  Removed FAST variable qualifier.
                 Cleaned up formatting and updated copyright for T2.2.
01e,12may95,p_m  adapted to support host based tt().
01d,26oct94,hdn  added a MAX_LOOPCOUNT to avoid infinite loop.
01c,09dec93,hdn  added a forward declaration of trcCountArgs().
                 commented out trcFollowJmp(pc) in trcFindFuncStart().
01b,01jun93,hdn  added third parameter tid to trcStack().
                 updated to 5.1.
                  - changed functions to ansi style
                  - changed VOID to void
                  - changed copyright notice
01a,16jul92,hdn  written based on TRON version.
*/

/*
This module provides a routine, trcStack(), which traces a stack
given the current frame pointer, stack pointer, and program counter.
The resulting stack trace lists the nested routine calls and their arguments.

This module provides the low-level stack trace facility.
A higher-level symbolic stack trace, implemented on top of this facility,
is provided by the routine tt() in dbgLib.

SEE ALSO: dbgLib, tt(),
.pG "Debugging"
*/

#include "vxWorks.h"
#include "regs.h"
#include "stdio.h"
#include "stdlib.h"
#include "symLib.h"
#include "sysSymTbl.h"
#include "private/funcBindP.h"

#define MAX_TRACE_DEPTH       40  /* max number of levels of stack to trace */
#define MAX_LOOPCOUNT        128  /* max loop count */

/* instruction patterns and masks */

#define ADDI08_0                0x83
#define ADDI08_1                0xc4
#define ADDI32_0                0x81
#define ADDI32_1                0xc4
#define LEAD08_0                0x8d
#define LEAD08_1                0x64
#define LEAD08_2                0x24
#define LEAD32_0                0x8d
#define LEAD32_1                0xa4
#define LEAD32_2                0x24
#define JMPD08                  0xeb
#define JMPD32                  0xe9
#define ENTER                   0xc8
#define PUSH_EBP                0x55
#define MOV_ESP0                0x89
#define MOV_ESP1                0xe5
#define LEAVE                   0xc9
#define RET                     0xc3
#define RETADD                  0xc2
#define CALL_DIR                0xe8
#define CALL_INDIR0             0xff
#define CALL_INDIR1             0x10

#define ADDI08_0_MASK           0xff
#define ADDI08_1_MASK           0xff
#define ADDI32_0_MASK           0xff
#define ADDI32_1_MASK           0xff
#define LEAD08_0_MASK           0xff
#define LEAD08_1_MASK           0xff
#define LEAD08_2_MASK           0xff
#define LEAD32_0_MASK           0xff
#define LEAD32_1_MASK           0xff
#define LEAD32_2_MASK           0xff
#define JMPD08_MASK             0xff
#define JMPD32_MASK             0xff
#define ENTER_MASK              0xff
#define PUSH_EBP_MASK           0xff
#define MOV_ESP0_MASK           0xff
#define MOV_ESP1_MASK           0xff
#define LEAVE_MASK              0xff
#define RET_MASK                0xff
#define RETADD_MASK             0xff
#define CALL_DIR_MASK           0xff
#define CALL_INDIR0_MASK        0xff
#define CALL_INDIR1_MASK        0x38

#define DSM(addr,inst,mask)     ((*(addr) & (mask)) == (inst))


/* globals */

int trcDefaultArgs = 5;         /* default # of args to print if trc
                                 * can't figure out how many */

/* forward declarations */

LOCAL INSTR * trcFindCall (INSTR * returnAdrs);
LOCAL INSTR * trcFindFuncStart (int * fp, INSTR * pc);
LOCAL INSTR * trcFindDest (INSTR * callAdrs);
LOCAL INSTR * trcFollowJmp (INSTR * addr);
LOCAL void    trcDefaultPrint (INSTR * callAdrs, INSTR * funcAdrs, int nargs,
                               int * args);
LOCAL void    trcStackLvl (int * fp, INSTR * pc, int depth, FUNCPTR printRtn);
LOCAL int     trcCountArgs (INSTR * returnAdrs);

/*******************************************************************************
*
* trcStack - print a trace of function calls from the stack
*
* This routine provides the low-level stack trace function.  A higher-level
* symbolic stack trace, built on top of trcStack(), is provided by tt() in
* dbgLib.
*
* This routine prints a list of the nested routine calls that are on the
* stack, showing each routine with its parameters.
*
* The stack being traced should be quiescent.  The caller should avoid
* tracing its own stack.
*
* PRINT ROUTINE
* In order to allow symbolic or alternative printout formats, the call to
* this routine includes the <printRtn> parameter, which specifies a
* user-supplied routine to be called at each nesting level to print out the
* routine name and its arguments.  This routine should be declared as
* follows:
* .ne 7
* .CS
*     void printRtn
*         (
*         INSTR *  callAdrs,  /@ address from which routine was called @/
*         int      rtnAdrs,   /@ address of routine called             @/
*         int      nargs,     /@ number of arguments in call           @/
*         int *    args       /@ pointer to arguments                  @/
*         )
* .CE
* If <printRtn> is NULL, a default routine will be used that prints out just
* the call address, the function address, and the arguments as hexadecimal
* values.
*
* CAVEAT
* In order to do the trace, a number of assumptions are made.  In general,
* the trace will work for all C language routines and for assembly language
* routines that start with an PUSH %EBP MOV %ESP %EBP instruction.  Most 
* VxWorks assembly language routines include PUSH %EBP MOV %ESP %EBP 
* instructions for exactly this reason.
* However, routines written in other languages, strange entries into
* routines, or tasks with corrupted stacks can confuse the trace.  Also,
* all parameters are assumed to be 32-bit quantities, therefore structures
* passed as parameters will be displayed as a number of long integers.
*
* EXAMPLE
* The following sequence can be used
* to trace a VxWorks task given a pointer to the task's TCB:
* .CS
* REG_SET regSet;        /@ task's data registers @/
*
* taskRegsGet (taskId, &regSet);
* trcStack (&regSet, (FUNCPTR)printRtn, tid);
* .CE
*
* SEE ALSO: tt()
*
* NOMANUAL
*/

void trcStack
    (
    REG_SET * pRegSet,        /* pointer to register set */
    FUNCPTR   printRtn,       /* routine to print single function call */
    int       tid             /* task's id */
    )
    {
    int       val;            /* address gotten from symbol table */
    SYM_TYPE  type;           /* type associated with val */
    INSTR *   addr;           /* next instruction */
    int       stackSave;
    char *    pName = NULL;   /* string associated with val */

    INSTR *   pc    = pRegSet->pc;             /* program counter */
    int *     fp    = (int *)pRegSet->fpReg;   /* stack frame pointer (EBP) */
    int *     sp    = (int *)pRegSet->spReg;   /* stack pointer */

    /* use default print routine if none specified */

    if (printRtn == NULL)
        printRtn = (FUNCPTR)trcDefaultPrint;

    /*
     * if the current routine doesn't have a stack frame, then we fake one
     * by putting the old one on the stack and making fp point to that;
     * we KNOW we don't have a stack frame in a few restricted but useful
     * cases:
     *  1) we are at a PUSH %EBP MOV %ESP %EBP or RET or ENTER instruction,
     *  2) we are the first instruction of a subroutine (this may NOT be
     *     a PUSH %EBP MOV %ESP %EBP instruction with some compilers)
     */

    addr = trcFollowJmp (pc);

    if ((DSM(addr,   PUSH_EBP, PUSH_EBP_MASK) && 
         DSM(addr+1, MOV_ESP0, MOV_ESP0_MASK) &&
         DSM(addr+2, MOV_ESP1, MOV_ESP1_MASK)) ||

        (DSM(addr,   ENTER,    ENTER_MASK))    ||
        (DSM(addr,   RET,      RET_MASK))      ||
        (DSM(addr,   RETADD,   RETADD_MASK))   ||

        ((sysSymTbl != NULL) &&
         (symByValueFind (sysSymTbl, (UINT) pc, &pName, &val, &type) == OK) &&
         (val == (int) pc)))
        {
        /* no stack frame - fake one */

        stackSave = *(sp - 1);      /* save value we're going to clobber */
        *(sp - 1) = (int)fp;        /* make new frame pointer by */
                                    /* sticking old one on stack */
        fp = sp - 1;                /* and pointing to it */

        trcStackLvl (fp, pc, 0, printRtn);        /* do stack trace */

        *(sp - 1) = stackSave;                    /* restore stack */
        }
    else if ((DSM(addr-1, PUSH_EBP, PUSH_EBP_MASK) && 
              DSM(addr,   MOV_ESP0, MOV_ESP0_MASK) &&
              DSM(addr+1, MOV_ESP1, MOV_ESP1_MASK)))
        {
        fp = sp;
        trcStackLvl (fp, pc, 0, printRtn);        /* do stack trace */
        }
    else
        {
        trcStackLvl (fp, pc, 0, printRtn);        /* do stack trace */
        }

    if (pName != NULL)
        {
        free (pName);  /* new API requires this */
        }
    }
/************************************************************************
*
* trcStackLvl - recursive stack trace routine
*
* This routine is recursive, being called once for each level of routine
* nesting.  The maximum recursion depth is limited to 40 to prevent
* garbage stacks from causing this routine to continue unbounded.
* The "depth" parameter on the original call should be 0.
*/

LOCAL void trcStackLvl
    (
    int *    fp,        /* stack frame pointer (EBP) */
    INSTR *  pc,        /* program counter */
    int      depth,     /* recursion depth */
    FUNCPTR  printRtn   /* routine to print single function call */
    )
    {
    INSTR *  returnAdrs;


    if (fp == NULL)
        return;        /* stack is untraceable */

    returnAdrs = (INSTR *) *(fp + 1);

    /* handle oldest calls first, up to MAX_TRACE_DEPTH of them */

    if (((void *)*fp != NULL) && (depth < MAX_TRACE_DEPTH))
        {
        trcStackLvl ((int *) *fp, returnAdrs, depth + 1, printRtn);
        }

    (* printRtn) (trcFindCall (returnAdrs), trcFindFuncStart (fp, pc),
                  trcCountArgs (returnAdrs), fp + 2);
    }
/*******************************************************************************
*
* trcDefaultPrint - print a function call
*
* This routine is called by trcStack to print each level in turn.
*
* If nargs is specified as 0, then a default number of args (trcDefaultArgs)
* is printed in brackets ("[..]"), since this often indicates that the
* number of args is unknown.
*/

LOCAL void trcDefaultPrint
    (
    INSTR * callAdrs,   /* address from which function was called */
    INSTR * funcAdrs,   /* address of function called */
    int     nargs,      /* number of arguments in function call */
    int *   args        /* pointer to function args */
    )
    {
    int     i;
    BOOL    doingDefault = FALSE;

    /* if there is no printErr routine do nothing */

    if (_func_printErr == NULL)
        return;