minix/commands/mdb/sym.c
David van Moolenbroek d3fc0eca1d mdb(1) fixes:
- allow core file offsets with high bit set
- repair and enable gcc-compiled binary support
- fix bug leading to random command execution
- remove obsolete ptrace.2 manpage
2009-12-29 21:38:26 +00:00

532 lines
10 KiB
C

/*
* sym.c for mdb
*/
#include "mdb.h"
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <a.out.h>
#include "proto.h"
struct symtab_s
{
struct nlist *start;
struct nlist *end;
int text;
int data;
unsigned nsym;
};
PRIVATE struct symtab_s symtab;
PRIVATE int type_of_exec;
FORWARD _PROTOTYPE( int check_exec, (struct exec *hdr) );
FORWARD _PROTOTYPE( void sortsyms , (struct nlist *array , struct nlist *top ));
FORWARD _PROTOTYPE( int symeq , (char *t , struct nlist *sp ));
FORWARD _PROTOTYPE( int symprefix , (char *t , struct nlist *sp ));
FORWARD _PROTOTYPE( struct nlist *findsname, (char *name, int is_text, int allflag) );
FORWARD _PROTOTYPE( void outsym, (struct nlist *sp, off_t off) );
FORWARD _PROTOTYPE( struct nlist *findsval, (off_t value, int where) );
PUBLIC void syminit( filename )
char *filename;
{
int fd;
struct exec header;
register struct symtab_s *tp;
tp = &symtab;
if ( (fd = open( filename, O_RDONLY)) < 0) {
fprintf(stderr, "Couldn't open %s.\n", filename);
perror(filename);
exit(1);
}
if( read( fd, (char *) &header, sizeof header ) != sizeof header )
{
fprintf(stderr, "Couldn't read %d bytes from %s.\n", sizeof(header), filename);
close( fd );
exit(1);
}
type_of_exec = check_exec(&header);
#if EXTRA_SYMBOLS
if ( type_of_exec == GNU_SYMBOLS) {
close(fd);
gnu_init(filename);
return;
}
#endif
/* For MINIX EXEC */
if ( lseek( fd, A_SYMPOS( header ), 0 ) != A_SYMPOS( header ) )
{
do_error( "mdb - reading header" );
close( fd );
exit(1);
}
if ( (int) header.a_syms < 0 ||
(unsigned) header.a_syms != header.a_syms ||
(tp->start = (struct nlist *) malloc( (unsigned) header.a_syms ))
== (struct nlist *) NULL &&
header.a_syms != 0 )
{
Printf("mdb: no room for symbol table" );
close( fd );
return;
}
if ( read( fd, (char *) tp->start, (int) header.a_syms ) < 0 )
{
do_error( "mdb - reading symbol table" );
close( fd );
return;
}
close( fd );
tp->nsym = (unsigned) header.a_syms / sizeof (struct nlist);
tp->end = tp->start + tp->nsym;
tp->text = 0x07;
tp->data = 0x0F;
/* sort on value only, name search not used much and storage a problem */
Printf("Sorting %d MINIX symbols ....", tp->nsym );
sortsyms( tp->start, tp->end );
Printf("\n");
}
/* Check exec file
* return type of exec
* or exit
*/
PRIVATE int check_exec(hdr)
struct exec *hdr;
{
long magic;
/* Check MAGIC number */
if (hdr->a_magic[0] != A_MAGIC0 || hdr->a_magic[1] != A_MAGIC1) {
Printf("mdb: invalid magic number in exec header - %02x %02x\n",
hdr->a_magic[0],
hdr->a_magic[1]);
exit(1);
}
/* Check CPU */
#if (CHIP == INTEL)
#if (_WORD_SIZE == 4)
if (hdr->a_cpu != A_I80386)
#else
if (hdr->a_cpu != A_I8086)
#endif
#endif
#if (CHIP == M68000)
if (hdr->a_cpu != A_M68K)
#endif
{
Printf("mdb: invalid cpu in exec header - %04x\n",
hdr->a_cpu);
exit(1);
}
is_separate = FALSE;
#ifdef MINIX_PC
if (hdr->a_flags & A_SEP)
is_separate = TRUE;
#endif
#if GNU_SUPPORT
if (hdr->a_flags & A_NSYM)
return GNU_SYMBOLS;
#endif
/*
* A_EXEC is not being set by current cc
* It was set in Minix 1.5.0
*/
#if 0
/* Check flags - separate I & D or not */
if (hdr->a_flags & A_EXEC)
is_separate = FALSE;
else {
Printf("mdb: object file not exec %04x\n",
hdr->a_flags);
exit(1);
}
#endif
return MINIX_SYMBOLS;
}
PUBLIC long symbolvalue( name, is_text )
char *name;
int is_text;
{
register struct nlist *sp;
#if EXTRA_SYMBOLS
if ( type_of_exec == GNU_SYMBOLS )
return gnu_symbolvalue( name, is_text );
#endif
/* For MINIX EXEC */
sp = findsname(name, is_text, 0);
if (sp != NULL)
return sp->n_value;
else
return 0L;
}
PRIVATE struct nlist *findsname( name, is_text, allflag )
char *name;
int is_text;
int allflag;
{
char *s;
unsigned char sclass;
int schar;
char *send;
register struct nlist *sp;
register struct symtab_s *tp;
tp = &symtab;
if ( allflag )
{
/* find and print all matching symbols */
for ( sp = tp->start; sp < tp->end; ++sp )
{
if ( symprefix( name, sp ) )
{
sp = sp;
for ( s = sp->n_name, send = s + sizeof sp->n_name;
*s != 0 && s < send; ++s )
outbyte( *s );
for ( ; s <= send; ++s )
outspace();
switch( sp->n_sclass & N_SECT )
{
case N_ABS: schar = 'a'; break;
case N_TEXT: schar = 't'; break;
case N_DATA: schar = 'd'; break;
case N_BSS: schar = 'b'; break;
default: schar = '?'; break;
}
if ( (sp->n_sclass & N_CLASS) == C_EXT && schar != '?' )
schar += 'A' - 'a';
outbyte( schar );
outspace();
#if (_WORD_SIZE == 2)
outh16( (u16_t) sp->n_value );
#else
outh32( sp->n_value );
#endif
outbyte('\n');
}
}
}
else
{
/* find symbol by dumb linear search */
for ( sp = tp->start; sp < tp->end; ++sp )
{
sclass = sp->n_sclass & N_SECT;
if ( (is_text && sclass == N_TEXT ||
!is_text && (sclass == N_DATA || sclass == N_BSS)) &&
symeq( name, sp ) )
return sp;
}
}
return NULL;
}
PRIVATE struct nlist *findsval( value, where )
off_t value;
int where;
{
int left;
int middle;
int right;
unsigned char sclass;
register struct nlist *sp;
register struct symtab_s *tp;
tp = &symtab;
/* find last symbol with value <= desired one by binary search */
for ( left = 0, right = tp->nsym - 1; left <= right; )
{
middle = (left + right) / 2;
sp = tp->start + middle;
if ( value < sp->n_value )
right = middle - 1;
else
left = middle + 1;
}
if ( right >= 0 )
/* otherwise tp->start + right may wrap around to > tp->start !! */
for ( sp = tp->start + right; sp >= tp->start; --sp )
{
if ( (sp->n_sclass & N_CLASS) != C_EXT ) continue;
sclass = sp->n_sclass & N_SECT;
if ( (where == CSEG && sclass == N_TEXT ||
where != CSEG && (sclass == N_DATA || sclass == N_BSS)) )
return sp;
}
return NULL;
}
PUBLIC void printhex(v)
off_t v;
{
if ( v >= 65536L )
outh32( v );
else if ( v >= 256 )
outh16( (u16_t) v );
else
outh8( (u8_t) v );
}
PRIVATE void outsym( sp, off )
struct nlist *sp;
off_t off;
{
register char *s;
char *send;
for ( s = sp->n_name, send = s + sizeof sp->n_name; *s != 0 && s < send; ++s )
outbyte( *s );
if ( (off -= sp->n_value) != 0 )
{
outbyte( '+' );
printhex(off);
}
}
/* shell sort symbols on value */
PRIVATE void sortsyms( array, top )
struct nlist *array;
struct nlist *top;
{
int gap;
int i;
int j;
register struct nlist *left;
register struct nlist *right;
struct nlist swaptemp;
int size;
size = top - array;
/* choose gaps according to Knuth V3 p95 */
for ( gap = 1, i = 4; (j = 3 * i + 1) < size; gap = i, i = j )
;
do
{
for ( j = gap; j < size; ++j )
for ( i = j - gap; i >= 0; i -= gap )
{
left = array + i;
right = array + (i + gap);
if ( (off_t) left->n_value <=
right->n_value )
break;
swaptemp = *left;
*left = *right;
*right = swaptemp;
}
}
while ( (gap /= 3) != 0 );
}
PUBLIC void symbolic( value, separator )
off_t value;
int separator;
{
register struct nlist *sp;
long off;
#if EXTRA_SYMBOLS
if ( type_of_exec == GNU_SYMBOLS ) {
gnu_symbolic( value, separator );
return;
}
#endif
/* For MINIX EXEC */
if (value < st_addr || value > end_addr) {
outstr("0x");
printhex(value);
outbyte(separator);
return;
}
if ( (sp = findsval( value, CSEG )) != NULL )
{
outsym( sp, value );
}
else if ( (sp = findsval( value, DSEG )) != NULL )
{
outsym( sp, value );
}
else
{
outstr("_start");
off = value - st_addr;
if ( off != 0 )
{
outbyte( '+' );
printhex(off);
}
}
outbyte( separator );
}
PRIVATE int symeq( t, sp )
register char *t;
struct nlist *sp;
{
return strncmp( t, sp->n_name, sizeof sp->n_name ) == 0;
}
PRIVATE int symprefix( t, sp )
register char *t;
struct nlist *sp;
{
register char *s;
char *send;
for ( ; *t == '_'; ++t )
;
for ( s = sp->n_name, send = s + sizeof sp->n_name;
s < send && *s == '_'; ++s )
;
return strncmp( s, t, (size_t)(send - s) ) == 0;
}
/* list all symbols - test for selection criteria */
PUBLIC void listsym(cmd)
char *cmd;
{
register struct symtab_s *tp;
register struct nlist *sp;
char *s;
char *send;
char schar;
char tchar;
/* set selection */
cmd = skip(cmd+1);
if( *cmd == '\n' || *cmd == ';' )
tchar = '*';
else
tchar = *cmd;
#if EXTRA_SYMBOLS
if ( type_of_exec == GNU_SYMBOLS ) {
gnu_listsym(tchar);
return;
}
#endif
/* For MINIX EXEC */
tp = &symtab;
for ( sp = tp->start; sp < tp->end; ++sp )
{
switch( sp->n_sclass & N_SECT )
{
case N_ABS: schar = 'a'; break;
case N_TEXT: schar = 't'; break;
case N_DATA: schar = 'd'; break;
case N_BSS: schar = 'b'; break;
default: schar = '?'; break;
}
if ( (sp->n_sclass & N_CLASS) == C_EXT && schar != '?' )
schar += 'A' - 'a';
/* check for selection */
if ( tchar != '*' && schar != tchar)
continue;
/* print symbol type and value */
for ( s = sp->n_name, send = s + sizeof sp->n_name;
*s != 0 && s < send; ++s ) outbyte( *s );
for ( ; s <= send; ++s ) outspace();
outbyte( schar );
outspace();
#if (_WORD_SIZE == 2)
outh16( (u16_t) sp->n_value );
#else
outh32( sp->n_value );
#endif
outbyte('\n');
}
}
PUBLIC int text_symbol(value)
off_t value;
{
struct nlist *sp;
#if EXTRA_SYMBOLS
if ( type_of_exec == GNU_SYMBOLS )
return gnu_text_symbol(value);
#endif
if ((sp = findsval(value, CSEG)) != NULL && sp->n_value == value)
{
outsym(sp, value);
return TRUE;
}
else
return FALSE;
}
PUBLIC int finds_data(off,data_seg)
off_t off;
int data_seg;
{
struct nlist *sp;
#if EXTRA_SYMBOLS
if ( type_of_exec == GNU_SYMBOLS )
return gnu_finds_data(off,data_seg);
#endif
if ((sp = findsval(off, data_seg)) != NULL)
{
outsym(sp, off);
return TRUE;
}
else
return FALSE;
}
PUBLIC int finds_pc(pc)
off_t pc;
{
struct nlist *sp;
#if EXTRA_SYMBOLS
if ( type_of_exec == GNU_SYMBOLS )
return gnu_finds_pc(pc);
#endif
if ((sp = findsval(pc, CSEG)) != NULL)
{
outsym(sp, pc);
return TRUE;
}
else
return FALSE;
}