minix/commands/mdb/mdb.c
2012-03-25 21:58:14 +02:00

1029 lines
22 KiB
C

/*
* mdb.c - MINIX program debugger
*
* Written by Bruce D. Szablak
*
* This free software is provided for non-commerical use. No warrantee
* of fitness for any use is implied. You get what you pay for. Anyone
* may make modifications and distribute them, but please keep this header
* in the distribution.
*/
/*
* Originally ported to MINIX-PC and MINIX-386 by Bruce Evans.
* NB: the original sym.c and mdbdis86.c come from his 'db'
*
* Added by Philip Murton:
*
* 2.0 'Core' file functions
* 2.1 Support for GNU exec
* 2.2 Changes for Minix 1.6.x Beta
* 2.3 Changes for Minix 1.7.0 and trace syscalls
* 2.4 Changes for Minix 1.7.2 and clean up
* 2.5.1 Add better help
* 2.5.2 Added io.c for logging options
* 2.5.3 Minor changes and tested with Minix 1.7.4
* 2.5.4 Command arguments processing improved (Thanks to Will Rose)
* 2.6.0 Final Version for MINIX CD (Sept/96)
*/
#define _MAIN_MDB
#include "mdb.h"
#include <minix/type.h>
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <errno.h>
#include <sys/wait.h>
#define ptrace mdbtrace
#include <sys/ptrace.h>
#include <setjmp.h>
#include "proto.h"
#include <machine/archtypes.h>
#include <kernel/const.h>
#include <kernel/type.h>
#include <kernel/proc.h>
/* buffer for proc and pointer to proc */
extern struct proc *prc;
#define MAXLINE 128
#define MAXARG 20
static unsigned long lastexp = 0L; /* last expression and segment */
static int lastseg = NOSEG;
static char *prog; /* prog name */
static char sbuf[MAXLINE];
static char cbuf[MAXLINE];
static char *cmd; /* current command */
static char *cmdstart; /* start of command */
static jmp_buf mainlp;
struct b_pnt {
struct b_pnt *nxt, *prv;
long addr;
long oldval;
char cmd[1];
} *b_head, *curpnt;
int main(int argc, char *argv[]);
static void cleanup(void);
static void freepnt(struct b_pnt *pnt );
static void findbpnt(int verbose );
static int exebpnt(int restart );
static void catch(int sig );
static int run(char *name , char *argstr , int tflg );
static int dowait(void);
static void backtrace(int all );
static void modify(long addr , int cnt , int verbose , int size );
static void display(long addr , int req );
static void fill(long addr , int req );
static void dorun(char *cmd );
static void not_for_core(void);
static void command(void);
static void cleanup()
{
curpid = 0;
curpnt = NULL;
while (b_head) freepnt(b_head);
}
static void findbpnt(verbose)
int verbose;
{
for (curpnt = b_head; curpnt; curpnt = curpnt->nxt) {
if (curpnt->addr == PC_MEMBER(prc) - BREAKPOINT_ADVANCE) {
ptrace(T_SETINS, curpid, curpnt->addr, curpnt->oldval);
ptrace(T_SETUSER, curpid, PC_OFF, curpnt->addr);
#if SYSCALLS_SUPPORT
if( syscalls )
do_syscall(curpnt->addr);
else if (curpnt->cmd[0] != '\n')
#else
if (curpnt->cmd[0] != '\n')
#endif
cmd = strcpy(cbuf, curpnt->cmd);
else if (verbose)
Printf("Breakpoint hit.\n");
return;
}
}
if (verbose) Printf("Unknown breakpoint hit.\n");
}
static int exebpnt(restart)
int restart;
{
ptrace(T_STEP, curpid, 0L, (long) restart);
if (dowait() == 0) return TRUE;
ptrace(T_SETINS, curpid, curpnt->addr, BREAK(curpnt->oldval));
curpnt = NULL;
return FALSE;
}
static void freepnt(pnt)
struct b_pnt *pnt;
{
if (pnt->prv)
pnt->prv->nxt = pnt->nxt;
else
b_head = pnt->nxt;
if (pnt->nxt) pnt->nxt->prv = pnt->prv;
if (curpid > 0) ptrace(T_SETINS, curpid, pnt->addr, pnt->oldval);
free(pnt);
if (pnt == curpnt) curpnt = NULL;
}
long breakpt(addr, cmd)
long addr;
char *cmd;
{
struct b_pnt *new;
if (curpid <= 0) {
Printf("No active process.\n");
return 0L;
}
for (new = b_head; new; new = new->nxt)
if (new->addr == addr) {
Printf("Breakpoint already exists here.\n");
return 0L;
}
new = (struct b_pnt *) malloc(sizeof(struct b_pnt) + strlen(cmd));
if (new == NULL) {
Printf("No room for new breakpoint.\n");
return 0L;
}
new->nxt = b_head;
new->prv = 0;
if (b_head) b_head->prv = new;
b_head = new;
new->addr = addr;
strcpy(new->cmd, cmd);
new->oldval = ptrace(T_GETINS, curpid, addr, 0L);
ptrace(T_SETINS, curpid, addr, BREAK(new->oldval));
if (ptrace(T_GETINS, curpid, addr, 0L) != BREAK(new->oldval)) {
do_error("Can't set breakpoint");
freepnt(new);
return 0L;
}
return new->oldval;
}
static void catch(sig)
int sig;
{
signal(sig, catch);
if (sig == SIGINT || sig == SIGQUIT) return;
tstart(T_EXIT, 0, sig, 0);
exit(0);
}
static int dowait()
{
int stat;
if (corepid > 0) return cursig = 0;
while (wait(&stat) != curpid) {};
if ( WIFEXITED(stat) ) {
if (WEXITSTATUS(stat) != 127)
Printf("child exited with status %d\n", WEXITSTATUS(stat));
cleanup();
return 0;
}
if ( WIFSIGNALED(stat) ) {
Printf("child terminated by signal %d\n", WTERMSIG(stat) );
if (_LOW(stat) & 0x80) Printf("(core dumped)\n");
cleanup();
return 0;
}
return cursig = WSTOPSIG(stat);
}
void tstart(req, verbose, val, cnt)
int req, verbose, val, cnt;
{
if (curpid == 0) {
if (verbose) Printf("No active process.\n");
return;
}
if (req == T_EXIT) {
ptrace(T_EXIT, curpid, 0L, (long) val);
dowait();
return;
}
if (cnt == 0) cnt = 1;
do {
if (curpnt) {
if (exebpnt(val)) return;
if (req == T_RESUME) cnt++;
val = 0;
} else {
ptrace(req, curpid, 0L, (long) val);
if (dowait() == 0) return;
val = 0;
switch (cursig) {
case SIGEMT: /* breakpoint */
update();
findbpnt(cnt <= 1);
break;
case SIGTRAP: /* trace trap? */
if (req == T_STEP) break;
default: /* signal */
val = cursig;
break;
}
}
}
while (--cnt > 0);
update();
if ( verbose ) dasm((long) PC_MEMBER(prc), 1, 1);
}
static int run(name, argstr, tflg)
char *name, *argstr;
int tflg;
{
int procid;
char *argv[MAXARG], *inf = NULL, *outf = NULL;
int argc;
if ((procid = fork()) == 0) {
/* trace me */
if (tflg) ptrace(T_OK, 0, 0L, 0L);
argv[0] = name;
for (argc = 1;;) {
argstr = skip(argstr);
if (*argstr == '\n' || *argstr == ';') {
argv[argc] = 0;
if (inf) freopen(inf, "r", stdin);
if (outf) freopen(outf, "w", stdout);
if (tflg) {
execv(name, argv);
do_error("execv");
} else {
execvp(name, argv);
do_error("execvp");
}
exit(127);
}
if (*argstr == '<')
inf = argstr + 1;
else if (*argstr == '>')
outf = argstr + 1;
else if (argc == MAXARG) {
Printf("Too many arguments.\n");
exit(127);
} else
argv[argc++] = argstr;
while (!isspace(*argstr)) argstr++;
if (*argstr == '\n') argstr[1] = '\n', argstr[2] = 0;
*argstr++ = 0;
}
}
if (procid < 0) do_error("Fork failed.\n");
return procid;
}
static void dorun(cmd)
char *cmd;
{
if (curpid = run(prog, cmd, 1)) {
if (dowait()) {
ptrace(T_SETUSER, curpid, BP_OFF, 0L);
update();
Printf("Process stopped.\n");
}
}
}
/*
* backtrace - inspect the stack
*/
static void backtrace(all)
int all;
{
unsigned long pc, bp, off, val, obp;
if (curpid <= 0) {
Printf("No process.\n");
return;
}
pc = get_reg(curpid,PC_OFF);
bp = get_reg(curpid,BP_OFF);
if (bp == 0) {
Printf("No active frame.\n");
return;
}
errno = 0;
do {
symbolic(pc, '(');
pc = (ptrace(T_GETDATA, curpid, bp + ADDRSIZE, 0L)
>> SHIFT(ADDRSIZE)) & MASK(ADDRSIZE);
off = ptrace(T_GETINS, curpid, pc, 0L);
#ifdef DEBUG
if(debug)
Printf("Return address %lx Value %lx\n",pc,off);
#endif
obp = bp;
bp += 2 * ADDRSIZE;
/* Check for various instruction used to restore the stack.
* Should gives us the number of arguments.
* This is obvious dependent on interal features of the
* compiler used.
*/
if (ADDQ(off)) off = ADDQ_CNT(off) + bp;
#ifdef __mc68000__
else if (LEA(off))
off = LEA_DISP(off) + bp;
#endif
else if (ADDA(off))
off = ADDA_CNT(ptrace(T_GETINS, curpid, pc + 2, 0L)) + bp;
#if (CHIP == INTEL)
else if (INCSP2(off))
off = bp + 2*INTSIZE;
else if (POPBX2(off))
off = bp + 2*INTSIZE;
else if (POPCX2(off))
off = bp + 2*INTSIZE;
else if (POPBX(off))
off = bp + INTSIZE;
else if (POPCX(off))
off = bp + INTSIZE;
#endif
else
goto skiplp;
#ifdef DEBUG
if (debug)
Printf("Number of arguments: %d\n",(off-bp)/INTSIZE);
#endif
for (;;) {
if (errno) return;
val = (ptrace(T_GETDATA, curpid, bp, 0L)
>> SHIFT(INTSIZE)) & MASK(INTSIZE);
Printf("0x%0*lx", 2 * INTSIZE, val);
bp += INTSIZE;
if (bp >= off) break;
Printf(",");
}
skiplp:
Printf(")\n");
bp = (long) ( (reg_t) ptrace(T_GETDATA, curpid, obp, 0L) );
#ifdef DEBUG
if(debug)
Printf("Old BP %lx New %lx\n",obp,bp);
#endif
}
while (all && (reg_t) bp);
}
static void modify(addr, cnt, verbose, size)
long addr;
int cnt, verbose, size;
{
long curval, off;
if (curpid == 0) {
Printf("No active process.\n");
return;
}
curval = ptrace(T_GETDATA, curpid, addr, 0L) & MASK(size);
do {
if (cursig == SIGTRAP) cursig = 0;
if (verbose) {
off = get_reg(curpid, PC_OFF);
dasm(off, 1, 0);
}
if (curpnt && exebpnt(cursig))
return;
else {
ptrace(T_STEP, curpid, addr, 0L);
switch (dowait()) {
case 0:
return;
case SIGEMT:
update();
findbpnt(0);
break;
}
}
if (curval != ptrace(T_GETDATA, curpid, addr, 0L) & MASK(size)) {
Printf("Modification detected\n");
break;
}
}
while (--cnt);
update();
dasm((long) PC_MEMBER(prc), 1, 1);
return;
}
static void display(addr, req)
long addr;
int req;
{
int count, size, out, shift;
long val, msk;
char fmt;
if (curpid == 0) {
Printf("No active process\n");
return;
}
if (req == T_GETDATA && seg == T) req = T_GETINS;
count = strtol(cmd, &cmd, 0);
if (count == 0) count = 1;
cmd = skip(cmd);
if (*cmd == 'i' || *cmd == 'I') {
dasm(addr, count, *cmd == 'i');
return;
}
if (*cmd == 'y') {
symbolic(addr, '\n');
return;
}
switch (*cmd++) {
case 'b': size = sizeof(char); break;
case 'h': size = sizeof(short); break;
case 'l': size = sizeof(long); break;
default:
size = sizeof(int);
--cmd;
break;
}
switch (fmt = *cmd) {
case 'X':
case 'D':
size = sizeof(long);
break;
case 's':
addr = ptrace(req, curpid, addr, 0L);
req = T_GETDATA;
/* Fallthrough */
case 'a':
case 'c':
size = sizeof(char);
break;
}
out = 0;
msk = MASK(size);
shift = SHIFT(size);
do {
val = (ptrace(req, curpid, addr, 0L) >> shift) & msk;
if (out == 0) Printf("\n0x%0*lx: ", 2 * ADDRSIZE,
(addr >> SHIFT(ADDRSIZE)) & MASK(ADDRSIZE));
switch (fmt) {
case 'c':
Printf(isprint((int) (UCHAR(val))) ? " %c " : "\\%03o ",
(int) (UCHAR(val)));
if (++out == 8) out = 0;
break;
case 'u':
Printf("%12lu ", val);
if (++out == 4) out = 0;
break;
case 'x':
case 'X':
Printf("%*lx ", 2 * size, val);
if (++out == (size == 4 ? 4 : 8)) out = 0;
break;
case 'o':
Printf("%*lo ", 3 * size, val);
if (++out == (size == 4 ? 4 : 8)) out = 0;
break;
case 's':
case 'a':
if (val)
Printf("%c",val);
else
goto exitlp;
if (++out == 64) out = 0;
break;
default:
case 'd':
case 'D':
Printf("%12ld ", val);
if (++out == 4) out = 0;
break;
}
addr += size;
}
while (--count > 0 || fmt == 's' || fmt == 'a');
exitlp:
Printf("\n");
}
static void fill(addr, req)
long addr;
int req;
{
int count, size, shift;
long val, msk, nval;
if (curpid == 0) {
Printf("No active process\n");
return;
}
if (req == T_GETDATA && seg == T) {
req = T_GETINS;
Printf("mdb: warning - modifying text\n");
}
count = strtol(cmd, &cmd, 0);
if ( count == 0 ) count = 1;
switch (*cmd++) {
case 'b': size = sizeof(char); break;
case 'h': size = sizeof(short); break;
case 'l': size = sizeof(long); break;
default:
size = sizeof(int);
--cmd;
break;
}
shift = SHIFT(size);
msk = MASK(size);
cmd = getexp(cmd, &nval, &seg);
#ifdef DEBUG
if (debug)
Printf("Filling for Count=%d Size=%d val=%lx\n",count,size,nval);
#endif
nval <<= shift;
do {
val = ptrace(req, curpid, addr, 0L) | (nval & msk);
val &= (nval | ~msk);
ptrace(req + 3, curpid, addr, val);
addr += size;
}
while (--count > 0);
}
static void not_for_core()
{
if (corepid > 0)
mdb_error("Illegal command for 'core' file\n");
}
static void command()
{
char c, *p;
int i;
int size;
int stat;
long exp, lj, lk;
struct b_pnt *bp;
seg = NOSEG; /* don't restrict segment expressions are in */
cmdstart = cmd = skip(cmd);
cmd = getexp(cmd, &exp, &seg);
if (cmd == cmdstart) {
/* Not an expression */
if (corepid < 0) { /* default to pc for running processs */
seg = T;
exp = PC_MEMBER(prc);
} else {
seg = lastseg;
exp = lastexp;
}
/* Is it a help command */
cmd = skip(cmd+1);
if (*cmd == '?') {
help_on(*cmdstart);
*cmd = '\n';
return;
}
else
cmd = cmdstart;
}
if (seg == NOSEG) seg = T; /* Absolute becomes Text */
lastexp = exp; /* save last expression */
lastseg = seg;
#ifdef DEBUG
if(debug)
Printf("Current address 0x%0*lx and segment %d\n", 2 * ADDRSIZE, exp, seg);
#endif
/* Check commands */
switch (c = *cmd++) {
case 'r': /* illegal for 'core' files */
case 'R':
case 'k':
case 'B':
case 'd':
case 'D': not_for_core();
break;
case 'b': /* illegal for 'core' files */
case 'c': /* Otherwise run process first */
case 'C':
case 'm':
case 'M':
#if SYSCALLS_SUPPORT
case 'z':
#endif
case 'i':
case 'I': not_for_core();
if (curpid <= 0) dorun("\n");
break;
case 's': if (curpid <= 0) dorun("\n");
break;
default: break;
}
switch (c) {
case '!': /* escape to shell */
if (cmd == cmdstart + 1) {
cmd = skip(cmd);
if (*cmd == '\n' || *cmd == ';') {
i = run("/bin/sh", "\n", 0);
} else {
for (p = cmd + 1; *p && !isspace(*p); p++) {
};
*p++ = 0;
i = run(cmd, *p ? p : "\n", 0);
}
if (i > 0) while (wait(&stat) != i) {};
break;
}
if (corepid > 0) longjmp(mainlp, 0);
break;
case 'T': /* top line of backtrace */
backtrace(0);
break;
case 't': /* back trace */
backtrace(1);
break;
case '/': /* print variable value */
display(exp, T_GETDATA);
break;
case 'x': /* print registers and instruction */
if (disp_regs()) break;
/* FALLTHROUGH */
case 'X': /* print instruction - X n [, n] */
lj = strtol(cmd, &cmd, 0);
lk = 0;
if (*cmd != '\n')
lk = strtol(++cmd, &cmd, 0);
if (curpid > 0)
dasm(exp + lk, lj ? lj : 1, 1);
else
Printf("No active process.\n");
break;
case 'R': /* run program with no args */
case 'r': /* run program with args (possibly defaulted) */
tstart(T_EXIT, 0, 0, 0);
if (c == 'r') {
cmd = skip(cmd);
if (*cmd == '\n' || *cmd == ';')
cmd = sbuf;
else
strcpy(sbuf, cmd);
} else {
cmd = "\n";
}
dorun(cmd);
break;
case 'c': /* continue program - ignore signal */
cursig = 0;
case 'C': /* continue program - handle signal */
i = 0;
if (seg == T && curpnt == 0 && cmd != cmdstart + 1) {
breakpt(exp, "\n");
curpnt = b_head;
ptrace(T_SETINS, curpid, curpnt->addr, curpnt->oldval);
i = 1;
}
tstart(T_RESUME, 1, cursig, (int) strtol(cmd, &cmd, 0));
/* remove temporary bp */
if (i) freepnt(b_head);
if (cursig == SIGEMT) return;
if (curpid) Printf("Process stopped by signal %d\n", cursig);
break;
case 'i': /* single step - ignore signal */
tstart(T_STEP, 1, 0, (int) strtol(cmd, &cmd, 0));
break;
case 'I': /* single step - handle signal */
tstart(T_STEP, 1, cursig, (int) strtol(cmd, &cmd, 0));
break;
case 'm': /* single step until location modified */
case 'M': /* single step until location modified - verbose */
cmd = skip(cmd);
switch (*cmd++) {
case 'b': size = sizeof(char); break;
case 'h': size = sizeof(short); break;
case 'l': size = sizeof(long); break;
default:
size = sizeof(int);
--cmd;
break;
}
modify(exp, (int) strtol(cmd, &cmd, 0), c == 'M', size);
break;
case 'k': /* kill current program */
tstart(T_EXIT, 1, 0, 0);
break;
case 'b': /* set a breakpoint at the given line */
#ifdef MINIX_PC
if (seg != T || exp > end_addr ) {
#else
if (seg != T || exp < st_addr || exp > et_addr ) {
#endif
Printf("Address not in text space.\n");
return;
}
breakpt(exp, skip(cmd));
cmd = "\n";
return;
case 'B': /* print list of currently active breakpoints */
for (i = 1, bp = b_head; bp; bp = bp->nxt, i++) {
Printf("%2d: ", i);
symbolic((long) bp->addr, '\t');
Printf("(0x%lx)\t- %s", bp->addr, bp->cmd);
}
break;
case 'd': /* delete breakpoint */
if (seg == T) {
for (bp = b_head; bp && bp->addr != exp; bp = bp->nxt);
if (bp) {
freepnt(bp);
break;
}
}
Printf("No such breakpoint.\n");
break;
case 'D': /* delete all breakpoints */
while (b_head) freepnt(b_head);
break;
case 's':
dump_stack( strtol(cmd, &cmd, 0) );
break;
case 'P':
paging = !paging;
if (paging) Printf("Paging is ON\n");
break;
case 'l':
case 'L':
logging(c,skip(cmd));
break;
#if SYSCALLS_SUPPORT
case 'z':
start_syscall( strtol(cmd, &cmd, 0) );
if ( syscalls )
Printf("Break point set - use the 'c n' command\n");
break;
#endif
case 'q': /* quit */
tstart(T_EXIT, 0, 0, 0);
logging(c,cmd);
case 'Q':
exit(0);
break;
case '\n':
case ';':
if (isdigit(*cmdstart))
symbolic(exp, '\n');
else
Printf("0x%0*lx\n", 2 * ADDRSIZE, exp);
--cmd;
break;
#ifdef DEBUG
case 'v': /* toggle debug */
debug = !debug;
if (debug) Printf("Debug flag ON\n");
break;
#endif
case 'e': /* list symbols */
listsym(cmd);
break;
case 'y': /* print mapping */
prtmap();
break;
case '?': /* print help */
help_page();
break;
case 'V': /* print version info */
version_info();
break;
case '@': /* command file */
cmd = skip(cmd);
openin(cmd);
*cmd = '\n';
return;
case '#': /* set register or variable */
cmd = skip(cmd + 1);
if (*cmd == '$') {
cmd++;
i = reg_addr(cmd);
set_reg(curpid, i, strtol(cmd+2, &cmd, 0) );
update();
break;
}
cmd = getexp(cmd, &exp, &seg);
fill(exp, T_GETDATA);
break;
default:
help_page();
break;
}
while (*cmd != '\n' && *cmd != ';') ++cmd;
if (*cmd == ';') cmd = skip(cmd + 1);
}
void mdb_error(s)
char *s;
{
Printf("%s",s);
longjmp(mainlp, 0);
}
int main(argc, argv)
int argc;
char *argv[];
{
int i, c;
char *p, *q, *r;
int opt_c = FALSE; /* load core file */
int opt_f = FALSE; /* load object file */
int opt_l = FALSE; /* log to file */
int opt_L = FALSE; /* log to file and screen */
prc = (struct proc *) lbuf;
strcpy(sbuf, "\n");
corepid = -1; /* set to indicate none */
prog = p = q = r = NULL;
if ( argc == 1 )
{
help_page();
exit(0);
}
/* Possible combinations of arguments:
* A single file name:
* If the name is 'core', the coreonly flag is set.
* The -c flag: examine a core file.
* One filename is required with this flag.
* The -f flag: examine an object file.
* One file name is required with this flag.
* The -L or -l flag: write to a log file.
* One file name is required with these flags.
* The -x flag: turn on debugging.
* Used for debugging, and followed by an integer
* argument which is the debugging level.
*
* If any files remain on the argument list, the first
* file is an executable, and the second a core file.
* If any filename starts with '@' it is assumed to
* to be a command file. Only one command file is
* loaded.
*/
/* check for default file name and fake out getopt */
if (strcmp(argv[1], "core") == 0) {
for (i = argc ; i > 1 ; i--)
argv[i] = argv[i - 1];
argv[i] = "-c";
argc++;
}
/* parse options */
opterr = 0;
while ((i = getopt(argc, argv, "c:f:L:l:x:")) != EOF) {
switch (i & 0377) {
case 'c': /* examine a core file */
if (opt_c == TRUE || opt_f == TRUE) {
help_page();
exit(1);
}
p = optarg;
opt_c = TRUE;
break;
case 'f': /* examine an object file */
if (opt_c == TRUE || opt_f == TRUE) {
help_page();
exit(1);
}
p = optarg;
opt_f = TRUE;
break;
case 'l': /* start logging */
if (opt_l == TRUE || opt_L == TRUE) {
help_page();
exit(1);
}
opt_l = TRUE;
logging(i, optarg);
break;
case 'L': /* start logging */
if (opt_l == TRUE || opt_L == TRUE) {
help_page();
exit(1);
}
opt_L = TRUE;
logging(i, optarg);
break;
#ifdef DEBUG
case 'x': /* set debug level */
debug = atoi(optarg);
break;
#endif
case '?': /* default arguments arrive here */
default:
help_page();
exit(1);
}
}
/* can't cope without filenames */
if (!opt_c && !opt_f && optind >= argc) {
help_page();
exit(1);
}
/* any remaining arguments are (optional) file names */
for (i = optind ; i < argc ; i++) {
if (*argv[i] == '@') { /* command file */
if (r == NULL) r = argv[i] + 1;
}
/* you can't combine a -c or -f object file and a core file */
else if (!opt_c && !opt_f && p == NULL) p = argv[i];
else if (q == NULL) q = argv[i]; /* core file */
}
/* initialise stuff - fairly tricky logic */
coreonly = opt_c;
fileonly = opt_f;
/* when examining files, prog == NULL */
if (!opt_c && !opt_f) {
prog = p;
syminit(prog);
}
/* file_init is called for non-core files.
* It is very similar to core_init. It opens the file and set
* various pointers so that we can read it using the same routines
* as a core file.
* NB: Currently there is no special provision to handle object files.
*/
/* A comment from Will Rose:
* It would be nice to have
* symbol tables available when reading a core
* or a.out, either as part of the executable or
* as a separate file.
* At least three separate types of file structure
* may be used by mdb - core files, a.out files, and
* object files (which may have several flavours).
* A set of routines is needed for each type, with
* a function switch table initialised when mdb is
* started up.
*/
if (opt_c) lastexp = core_init(p);
if (opt_f) lastexp = file_init(p);
if (q != NULL) lastexp = core_init(q);
if (r != NULL) openin(r);
for (i = 1; i < _NSIG; i++) signal(i, catch);
setjmp(mainlp);
while (get_cmd( cbuf, MAXLINE ) != NULL) {
if (strlen(cbuf) == sizeof(cbuf) - 1) {
Printf("Command line too long.\n");
continue;
}
cmd = cbuf;
command();
while (*cmd != '\n') command();
}
tstart(T_EXIT, 0, 0, 0);
exit(0);
}