process.c

早期freebsd实现

    }
    if (p->status != STOPPED) {
	if (p->exitval == 0) {
	    error("program exited\n");
	} else {
	    error("program exited with code %d\n", p->exitval);
	}
    }
}

/*
 * Return from execution when the given signal is pending.
 */

public psigtrace(p, sig, sw)
Process p;
int sig;
Boolean sw;
{
    if (sw) {
	p->sigset |= setrep(sig);
    } else {
	p->sigset &= ~setrep(sig);
    }
}

/*
 * Don't catch any signals.
 * Particularly useful when letting a process finish uninhibited.
 */

public unsetsigtraces(p)
Process p;
{
    p->sigset = 0;
}

/*
 * Turn off attention to signals not being caught.
 */

private sig_t sigfunc[NSIG];

private sigs_off()
{
    register int i;

    for (i = FIRSTSIG; i < LASTSIG; i++) {
	if (i != SIGKILL) {
	    sigfunc[i] = signal(i, SIG_IGN);
	}
    }
}

/*
 * Turn back on attention to signals.
 */

private sigs_on()
{
    register int i;

    for (i = FIRSTSIG; i < LASTSIG; i++) {
	if (i != SIGKILL) {
	    signal(i, sigfunc[i]);
	}
    }
}

/*
 * Get process information from user area.
 */

private getinfo (p, status)
register Process p;
register int status;
{
    register int i;
    Address addr;

    p->signo = (status&0177);
    p->exitval = ((status >> 8)&0377);
    if (p->signo != STOPPED) {
	p->status = FINISHED;
	p->pid = 0;
	p->reg[PROGCTR] = 0;
    } else {
	p->status = p->signo;
	p->signo = p->exitval;
	p->exitval = 0;
#       ifdef IRIS
	    p->mask = readreg(p, RPS);
#       else
	    p->sigcode = ptrace(UREAD, p->pid, &((struct user *)0)->u_code, 0);
	    p->mask = readreg(p, PS);
#       endif
	for (i = 0; i < NREG; i++) {
	    p->reg[i] = readreg(p, rloc[i]);
	    p->oreg[i] = p->reg[i];
	}
#       ifdef mc68000
	    if (p->status == STOPPED and p->signo == SIGTRAP and
		p->reg[PROGCTR] > CODESTART
	    ) {
		p->reg[PROGCTR] -= 2;
	    }
#       endif
	savetty(stdout, &(p->ttyinfo));
	addr = (Address) &(((struct user *) 0)->u_signal[p->signo]);
	p->sigstatus = (Address) ptrace(UREAD, p->pid, addr, 0);
    }
}

/*
 * Set process's user area information from given process structure.
 */

private setinfo (p, signo)
register Process p;
int signo;
{
    register int i;
    register int r;

    if (signo == DEFSIG) {
	if (istraced(p) and (p->sigstatus == 0 or p->sigstatus == 1)) {
	    p->signo = 0;
	}
    } else {
	p->signo = signo;
    }
    for (i = 0; i < NREG; i++) {
	if ((r = p->reg[i]) != p->oreg[i]) {
	    writereg(p, rloc[i], r);
	}
    }
    restoretty(stdout, &(p->ttyinfo));
}

/*
 * Return the address associated with the current signal.
 * (Plus two since the address points to the beginning of a procedure).
 */

public Address usignal (p)
Process p;
{
    Address r;

    r = p->sigstatus;
    if (r != 0 and r != 1) {
	r += FUNCOFFSET;
    }
    return r;
}

/*
 * Structure for reading and writing by words, but dealing with bytes.
 */

typedef union {
    Word pword;
    Byte pbyte[sizeof(Word)];
} Pword;

/*
 * Read (write) from (to) the process' address space.
 * We must deal with ptrace's inability to look anywhere other
 * than at a word boundary.
 */

private Word fetch();
private store();

private pio(p, op, seg, buff, addr, nbytes)
Process p;
PioOp op;
PioSeg seg;
char *buff;
Address addr;
int nbytes;
{
    register int i;
    register Address newaddr;
    register char *cp;
    char *bufend;
    Pword w;
    Address wordaddr;
    int byteoff;

    if (p->status != STOPPED) {
	error("program is not active");
    }
    cp = buff;
    newaddr = addr;
    wordaddr = (newaddr&WMASK);
    if (wordaddr != newaddr) {
	w.pword = fetch(p, seg, wordaddr);
	for (i = newaddr - wordaddr; i < sizeof(Word) and nbytes > 0; i++) {
	    if (op == PREAD) {
		*cp++ = w.pbyte[i];
	    } else {
		w.pbyte[i] = *cp++;
	    }
	    nbytes--;
	}
	if (op == PWRITE) {
	    store(p, seg, wordaddr, w.pword);
	}
	newaddr = wordaddr + sizeof(Word);
    }
    byteoff = (nbytes&(~WMASK));
    nbytes -= byteoff;
    bufend = cp + nbytes;
#ifdef tahoe
    if (((int)cp)&WMASK) {
	/*
	 * Must copy a byte at a time, buffer not word addressable.
	 */
	while (cp < bufend) {
	    if (op == PREAD) {
		w.pword = fetch(p, seg, newaddr);
		for (i = 0; i < sizeof(Word); i++)
		    *cp++ = w.pbyte[i];
	    } else {
		for (i = 0; i < sizeof(Word); i++)
		    w.pbyte[i] = *cp++;
		store(p, seg, newaddr, w.pword);
	    }
	    newaddr += sizeof(Word);
	}
    } else {
    /*
     * Buffer, word aligned, act normally...
     */
#endif
    while (cp < bufend) {
	if (op == PREAD) {
	    *((Word *) cp) = fetch(p, seg, newaddr);
	} else {
	    store(p, seg, newaddr, *((Word *) cp));
	}
	cp += sizeof(Word);
	newaddr += sizeof(Word);
    }
#ifdef tahoe
    }
#endif
    if (byteoff > 0) {
	w.pword = fetch(p, seg, newaddr);
	for (i = 0; i < byteoff; i++) {
	    if (op == PREAD) {
		*cp++ = w.pbyte[i];
	    } else {
		w.pbyte[i] = *cp++;
	    }
	}
	if (op == PWRITE) {
	    store(p, seg, newaddr, w.pword);
	}
    }
}

/*
 * Get a word from a process at the given address.
 * The address is assumed to be on a word boundary.
 *
 * A simple cache scheme is used to avoid redundant ptrace calls
 * to the instruction space since it is assumed to be pure.
 *
 * It is necessary to use a write-through scheme so that
 * breakpoints right next to each other don't interfere.
 */

private Integer nfetchs, nreads, nwrites;

private Word fetch(p, seg, addr)
Process p;
PioSeg seg;
register int addr;
{
    register CacheWord *wp;
    register Word w;

    switch (seg) {
	case TEXTSEG:
	    ++nfetchs;
	    wp = &p->word[cachehash(addr)];
	    if (addr == 0 or wp->addr != addr) {
		++nreads;
		w = ptrace(IREAD, p->pid, addr, 0);
		wp->addr = addr;
		wp->val = w;
	    } else {
		w = wp->val;
	    }
	    break;

	case DATASEG:
	    w = ptrace(DREAD, p->pid, addr, 0);
	    break;

	default:
	    panic("fetch: bad seg %d", seg);
	    /* NOTREACHED */
    }
    return w;
}

/*
 * Put a word into the process' address space at the given address.
 * The address is assumed to be on a word boundary.
 */

private store(p, seg, addr, data)
Process p;
PioSeg seg;
int addr;
Word data;
{
    register CacheWord *wp;

    switch (seg) {
	case TEXTSEG:
	    ++nwrites;
	    wp = &p->word[cachehash(addr)];
	    wp->addr = addr;
	    wp->val = data;
	    ptrace(IWRITE, p->pid, addr, data);
	    break;

	case DATASEG:
	    ptrace(DWRITE, p->pid, addr, data);
	    break;

	default:
	    panic("store: bad seg %d", seg);
	    /* NOTREACHED */
    }
}

/*
 * Flush the instruction cache associated with a process.
 */

private cacheflush (p)
Process p;
{
    bzero(p->word, sizeof(p->word));
}

public printptraceinfo()
{
    printf("%d fetchs, %d reads, %d writes\n", nfetchs, nreads, nwrites);
}

/*
 * Redirect input.
 * Assuming this is called from a child, we should be careful to avoid
 * (possibly) shared standard I/O buffers.
 */

private infrom (filename)
String filename;
{
    Fileid in;

    in = open(filename, 0);
    if (in == -1) {
	write(2, "can't read ", 11);
	write(2, filename, strlen(filename));
	write(2, "\n", 1);
	_exit(1);
    }
    fswap(0, in);
}

/*
 * Redirect standard output.
 * Same assumptions as for "infrom" above.
 */

private outto (filename)
String filename;
{
    Fileid out;

    out = creat(filename, 0666);
    if (out == -1) {
	write(2, "can't write ", 12);
	write(2, filename, strlen(filename));
	write(2, "\n", 1);
	_exit(1);
    }
    fswap(1, out);
}

/*
 * Swap file numbers, useful for redirecting standard input or output.
 */

private fswap(oldfd, newfd)
Fileid oldfd;
Fileid newfd;
{
    if (oldfd != newfd) {
	close(oldfd);
	dup(newfd);
	close(newfd);
    }
}

/*
 * Signal name manipulation.
 */

private String signames[NSIG] = {
    0,
    "HUP", "INT", "QUIT", "ILL", "TRAP",
    "IOT", "EMT", "FPE", "KILL", "BUS",
    "SEGV", "SYS", "PIPE", "ALRM", "TERM",
    0, "STOP", "TSTP", "CONT", "CHLD",
    "TTIN", "TTOU", "TINT", "XCPU", "XFSZ",
    "VTALRM", "PROF", "WINCH", "USR1", "USR2"
};

/*
 * Get the signal number associated with a given name.
 * The name is first translated to upper case if necessary.
 */

public integer siglookup (s)
String s;
{
    register char *p, *q;
    char buf[100];
    integer i;

    p = s;
    q = buf;
    while (*p != '\0') {
	if (*p >= 'a' and *p <= 'z') {
	    *q = (*p - 'a') + 'A';
	} else {
	    *q = *p;
	}
	++p;
	++q;
    }
    *q = '\0';
    p = buf;
    if (buf[0] == 'S' and buf[1] == 'I' and buf[2] == 'G') {
	p += 3;
    }
    i = 1;
    for (;;) {
	if (i >= sizeof(signames) div sizeof(signames[0])) {
	    error("signal \"%s\" unknown", s);
	    i = 0;
	    break;
	}
	if (signames[i] != nil and streq(signames[i], p)) {
	    break;
	}
	++i;
    }
    return i;
}

/*
 * Print all signals being ignored by the debugger.
 * These signals are auotmatically
 * passed on to the debugged process.
 */

public printsigsignored (p)
Process p;
{
    printsigs(~p->sigset);
}

/*
 * Print all signals being intercepted by
 * the debugger for the specified process.
 */

public printsigscaught(p)
Process p;
{
    printsigs(p->sigset);
}

private printsigs (set)
integer set;
{
    integer s;
    char separator[2];

    separator[0] = '\0';
    for (s = 1; s < sizeof(signames) div sizeof(signames[0]); s++) {
	if (set & setrep(s)) {
	    if (signames[s] != nil) {
		printf("%s%s", separator, signames[s]);
		separator[0] = ' ';
		separator[1] = '\0';
	    }
	}
    }
    if (separator[0] == ' ') {
	putchar('\n');
    }
}