coregrind/m_debuglog.c

/*--------------------------------------------------------------------*/
/*--- Debug (not-for-user) logging; also vprintf.     m_debuglog.c ---*/
/*--------------------------------------------------------------------*/

/*
   This file is part of Valgrind, a dynamic binary instrumentation
   framework.

   Copyright (C) 2000-2005 Julian Seward 
      jseward@acm.org

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file COPYING.
*/


/* Performs low-level debug logging that can safely run immediately
   after startup.  To minimise the dependencies on any other parts of
   the system, the only place the debug output may go is file
   descriptor 2 (stderr).
*/
/* This is the first-initialised module in the entire system!
   Therefore it is CRITICAL that it does not depend on any other code
   running first.  Hence only the following very limited includes.  We
   cannot depend (directly or indirectly) on any dynamic memory
   allocation facilities, nor on the m_libc facilities, since the
   latter depend on this module.  DO NOT MESS WITH THESE INCLUDES
   UNLESS YOU ARE 100% CERTAIN YOU UNDERSTAND THE CONSEQUENCES.
*/
/* This module is also different from all others in the sense that it
   is linked into both stage1 and stage2.  
*/
#include "basic_types.h"        /* basic types */
#include "pub_core_debuglog.h"  /* our own iface */


/*------------------------------------------------------------*/
/*--- Stuff to make us completely independent.             ---*/
/*------------------------------------------------------------*/

/* ----- x86-linux specifics ----- */

/* Arse!  Really I want to test VG_PLATFORM, but this does not
   seem to be possible. */
#if defined(__i386__) && defined(__linux__)

static UInt local_sys_write_stderr ( HChar* buf, Int n )
{
   UInt __res;
   __asm__ volatile (
      "movl  $4, %%eax\n"    /* %eax = __NR_write */
      "movl  $2, %%edi\n"    /* %edi = stderr */
      "movl  %1, %%ecx\n"    /* %ecx = buf */
      "movl  %2, %%edx\n"    /* %edx = n */
      "pushl %%ebx\n"
      "movl  %%edi, %%ebx\n"
      "int   $0x80\n"        /* write(stderr, buf, n) */
      "popl  %%ebx\n"
      "movl  %%eax, %0\n"    /* __res = eax */
      : "=mr" (__res)
      : "g" (buf), "g" (n)
      : "eax", "edi", "ecx", "edx"
   );
   if (__res < 0) 
      __res = -1;
   return __res;
}

static UInt local_sys_getpid ( void )
{
   UInt __res;
   __asm__ volatile (
      "movl $20, %%eax\n"  /* set %eax = __NR_getpid */
      "int  $0x80\n"       /* getpid() */
      "movl %%eax, %0\n"   /* set __res = eax */
      : "=mr" (__res)
      :
      : "eax" );
   return __res;
}

#elif defined(__x86_64__) && defined(__linux__)

static UInt local_sys_write_stderr ( HChar* buf, Int n )
{
   UInt __res;
   __asm__ volatile (
      "movq $1, %%rax\n"   /* set %rax = __NR_write */
      "movq $2, %%rdi\n"   /* set %rdi = stderr */
      "movq %1, %%rsi\n"   /* set %rsi = buf */
      "movl %2, %%edx\n"   /* set %edx = n */
      "syscall\n"          /* write(stderr, buf, n) */
      "movl %%eax, %0\n"   /* set __res = %eax */
      : "=mr" (__res)
      : "g" (buf), "g" (n)
      : "rax", "rdi", "rsi", "rdx" );
   if (__res < 0) 
      __res = -1;
   return __res;
}

static UInt local_sys_getpid ( void )
{
   UInt __res;
   __asm__ volatile (
      "movq $39, %%rax\n"  /* set %rax = __NR_getpid */
      "syscall\n"          /* getpid() */
      "movl %%eax, %0\n"   /* set __res = %eax */
      : "=mr" (__res)
      :
      : "rax" );
   return __res;
}

#else
#error Unknown VG_PLATFORM
#endif


/* ----- generic ----- */

/* strlen, so we don't need m_libc */
static Int local_strlen ( const HChar* str )
{
   Int i = 0;
   while (str[i] != 0) i++;
   return i;
}

static HChar local_toupper ( HChar c )
{
   if (c >= 'a' && c <= 'z')
      return c + ('A' - 'a'); 
   else
      return c;
}

/* Emit buf[0 .. n-1] to stderr.  Unfortunately platform-specific. 
*/
static void emit ( HChar* buf, Int n )
{
   if (n >= 1)
      (void)local_sys_write_stderr(buf, n);
}


/*------------------------------------------------------------*/
/*--- A simple, generic, vprintf implementation.           ---*/
/*------------------------------------------------------------*/

/* -----------------------------------------------
   Distantly derived from:

      vprintf replacement for Checker.
      Copyright 1993, 1994, 1995 Tristan Gingold
      Written September 1993 Tristan Gingold
      Tristan Gingold, 8 rue Parmentier, F-91120 PALAISEAU, FRANCE

   (Checker itself was GPL'd.)
   ----------------------------------------------- */

/* Some flags.  */
#define VG_MSG_SIGNED    1 /* The value is signed. */
#define VG_MSG_ZJUSTIFY  2 /* Must justify with '0'. */
#define VG_MSG_LJUSTIFY  4 /* Must justify on the left. */
#define VG_MSG_PAREN     8 /* Parenthesize if present (for %y) */
#define VG_MSG_COMMA    16 /* Add commas to numbers (for %d, %u) */


/* Copy a string into the buffer. */
static 
UInt myvprintf_str ( void(*send)(HChar,void*),
                     void* send_arg2,
                     Int flags, 
                     Int width, 
                     HChar* str, 
                     Bool capitalise )
{
#  define MAYBE_TOUPPER(ch) (capitalise ? local_toupper(ch) : (ch))
   UInt ret = 0;
   Int i, extra;
   Int len = local_strlen(str);

   if (width == 0) {
      ret += len;
      for (i = 0; i < len; i++)
          send(MAYBE_TOUPPER(str[i]), send_arg2);
      return ret;
   }

   if (len > width) {
      ret += width;
      for (i = 0; i < width; i++)
         send(MAYBE_TOUPPER(str[i]), send_arg2);
      return ret;
   }

   extra = width - len;
   if (flags & VG_MSG_LJUSTIFY) {
      ret += extra;
      for (i = 0; i < extra; i++)
         send(' ', send_arg2);
   }
   ret += len;
   for (i = 0; i < len; i++)
      send(MAYBE_TOUPPER(str[i]), send_arg2);
   if (!(flags & VG_MSG_LJUSTIFY)) {
      ret += extra;
      for (i = 0; i < extra; i++)
         send(' ', send_arg2);
   }

#  undef MAYBE_TOUPPER
   return ret;
}


/* Write P into the buffer according to these args:
 *  If SIGN is true, p is a signed.
 *  BASE is the base.
 *  If WITH_ZERO is true, '0' must be added.
 *  WIDTH is the width of the field.
 */
static 
UInt myvprintf_int64 ( void(*send)(HChar,void*), 
                       void* send_arg2,
                       Int flags, 
                       Int base, 
                       Int width, 
                       ULong p )
{
   HChar  buf[40];
   Int    ind = 0;
   Int    i, nc = 0;
   Bool   neg = False;
   HChar* digits = "0123456789ABCDEF";
   UInt   ret = 0;

   if (base < 2 || base > 16)
      return ret;
 
   if ((flags & VG_MSG_SIGNED) && (Long)p < 0) {
      p   = - (Long)p;
      neg = True;
   }

   if (p == 0)
      buf[ind++] = '0';
   else {
      while (p > 0) {
         if (flags & VG_MSG_COMMA && 10 == base &&
             0 == (ind-nc) % 3 && 0 != ind) 
         {
            buf[ind++] = ',';
            nc++;
         }
         buf[ind++] = digits[p % base];
         p /= base;
      }
   }

   if (neg)
      buf[ind++] = '-';

   if (width > 0 && !(flags & VG_MSG_LJUSTIFY)) {
      for(; ind < width; ind++) {
         /* vg_assert(ind < 39); */
         if (ind > 39) {
            buf[39] = 0;
            break;
         }
         buf[ind] = (flags & VG_MSG_ZJUSTIFY) ? '0': ' ';
      }
   }

   /* Reverse copy to buffer.  */
   ret += ind;
   for (i = ind -1; i >= 0; i--) {
      send(buf[i], send_arg2);
   }
   if (width > 0 && (flags & VG_MSG_LJUSTIFY)) {
      for(; ind < width; ind++) {
         ret++;
         /* Never pad with zeroes on RHS -- changes the value! */
         send(' ', send_arg2);
      }
   }
   return ret;
}


/* A simple vprintf().  */
/* EXPORTED */
UInt
VG_(debugLog_vprintf) ( 
   void(*send)(HChar,void*), 
   void* send_arg2,
   const HChar* format, 
   va_list vargs
)
{
   UInt ret = 0;
   Int  i;
   Int  flags;
   Int  width;
   Bool is_long;

   /* We assume that vargs has already been initialised by the 
      caller, using va_start, and that the caller will similarly
      clean up with va_end.
   */

   for (i = 0; format[i] != 0; i++) {
      if (format[i] != '%') {
         send(format[i], send_arg2);
         ret++;
         continue;
      }
      i++;
      /* A '%' has been found.  Ignore a trailing %. */
      if (format[i] == 0)
         break;
      if (format[i] == '%') {
         /* `%%' is replaced by `%'. */
         send('%', send_arg2);
         ret++;
         continue;
      }
      flags = 0;
      is_long = False;
      width = 0; /* length of the field. */
      if (format[i] == '(') {
         flags |= VG_MSG_PAREN;
         i++;
      }
      /* If ',' follows '%', commas will be inserted. */
      if (format[i] == ',') {
         flags |= VG_MSG_COMMA;
         i++;
      }
      /* If '-' follows '%', justify on the left. */
      if (format[i] == '-') {
         flags |= VG_MSG_LJUSTIFY;
         i++;
      }
      /* If '0' follows '%', pads will be inserted. */
      if (format[i] == '0') {
         flags |= VG_MSG_ZJUSTIFY;
         i++;
      }
      /* Compute the field length. */
      while (format[i] >= '0' && format[i] <= '9') {
         width *= 10;
         width += format[i++] - '0';
      }
      while (format[i] == 'l') {
         i++;
         is_long = True;
      }

      switch (format[i]) {
         case 'd': /* %d */
            flags |= VG_MSG_SIGNED;
            if (is_long)
               ret += myvprintf_int64(send, send_arg2, flags, 10, width, 
                                      (ULong)(va_arg (vargs, Long)));
            else
               ret += myvprintf_int64(send, send_arg2, flags, 10, width, 
                                      (ULong)(va_arg (vargs, Int)));
            break;
         case 'u': /* %u */
            if (is_long)
               ret += myvprintf_int64(send, send_arg2, flags, 10, width, 
                                      (ULong)(va_arg (vargs, ULong)));
            else
               ret += myvprintf_int64(send, send_arg2, flags, 10, width, 
                                      (ULong)(va_arg (vargs, UInt)));
            break;
         case 'p': /* %p */
            ret += 2;
            send('0',send_arg2);
            send('x',send_arg2);
            ret += myvprintf_int64(send, send_arg2, flags, 16, width, 
                                   (ULong)((UWord)va_arg (vargs, void *)));
            break;
         case 'x': /* %x */
            if (is_long)
               ret += myvprintf_int64(send, send_arg2, flags, 16, width, 
                                      (ULong)(va_arg (vargs, ULong)));
            else
               ret += myvprintf_int64(send, send_arg2, flags, 16, width, 
                                      (ULong)(va_arg (vargs, UInt)));
            break;
         case 'c': /* %c */
            ret++;
            send(va_arg (vargs, int), send_arg2);
            break;
         case 's': case 'S': { /* %s */
            char *str = va_arg (vargs, char *);
            if (str == (char*) 0) str = "(null)";
            ret += myvprintf_str(send, send_arg2, 
                                 flags, width, str, format[i]=='S');
            break;
         }
//         case 'y': { /* %y - print symbol */
//            Char buf[100];
//            Char *cp = buf;
//            Addr a = va_arg(vargs, Addr);
//
//            if (flags & VG_MSG_PAREN)
//               *cp++ = '(';
//            if (VG_(get_fnname_w_offset)(a, cp, sizeof(buf)-4)) {
//               if (flags & VG_MSG_PAREN) {
//                  cp += VG_(strlen)(cp);
//                  *cp++ = ')';
//                  *cp = '\0';
//               }
//               ret += myvprintf_str(send, send_arg2, flags, width, buf, 0);
//            }
//            break;
//         }
         default:
            break;
      }
   }
   return ret;
}


/*------------------------------------------------------------*/
/*--- Debuglog stuff.                                      ---*/
/*------------------------------------------------------------*/

/* Only print messages whose stated level is less than or equal to
   this.  By default, it makes this entire subsystem silent. */

static Int loglevel = 0;

/* EXPORTED */
/* Module startup. */
void VG_(debugLog_startup) ( Int level, HChar* who )
{
   if (level < 0)  level = 0;
   if (level > 10) level = 10;
   loglevel = level;
   VG_(debugLog)(1, "debuglog", 
                 "DebugLog system started by %s, "
                 "level %d logging requested\n", 
                 who, loglevel);
}

/* ------------ */

typedef 
   struct {
      HChar buf[100];
      Int   n;
   } 
   printf_buf;

static void add_to_buf ( HChar c, void* p )
{
   printf_buf* buf = (printf_buf*)p;

   if (buf->n >= 100-10 /*paranoia*/ ) {
      emit( buf->buf, local_strlen(buf->buf) );
      buf->n = 0;
      buf->buf[buf->n] = 0;      
   }
   buf->buf[buf->n++] = c;
   buf->buf[buf->n] = 0;
}

/* Send a logging message.  Nothing is output unless 'level'
   is <= the current loglevel. */
/* EXPORTED */
__attribute__((format(__printf__, 3, 4)))
void VG_(debugLog) ( Int level, const HChar* modulename,
                                const HChar* format, ... )
{
   UInt ret, pid;
   Int indent;
   va_list vargs;
   printf_buf buf;

   
   if (level > loglevel)
      return;

   indent = 2*level - 1;
   if (indent < 1) indent = 1;

   buf.n = 0;
   buf.buf[0] = 0;
   pid = local_sys_getpid();
   (void)myvprintf_str ( add_to_buf, &buf, 0, 2, "--", False );
   (void)myvprintf_int64 ( add_to_buf, &buf, 0, 10, 1, (ULong)pid );
   (void)myvprintf_str ( add_to_buf, &buf, 0, 1, ":", False );
   (void)myvprintf_int64 ( add_to_buf, &buf, 0, 10, 1, (ULong)level );
   (void)myvprintf_str ( add_to_buf, &buf, 0, 1, ":", False );
   (void)myvprintf_str ( add_to_buf, &buf, 0, 8, (HChar*)modulename, False );
   (void)myvprintf_str ( add_to_buf, &buf, 0, indent, "", False );

   va_start(vargs,format);
   
   ret = VG_(debugLog_vprintf) ( add_to_buf, &buf, format, vargs );

   if (buf.n > 0) {
      emit( buf.buf, local_strlen(buf.buf) );
   }

   va_end(vargs);
}



/*--------------------------------------------------------------------*/
/*--- end                                           m_debuglog.c ---*/
/*--------------------------------------------------------------------*/