safe.c

The MPICH-V patch for MPICH2 - the MPI Implementation

#include <unistd.h>
#include "ckpt.h"


static struct ckpt_restore safe_cr;

int
xread(int sd, void *buf, size_t len)
{
	char *p = (char *)buf;
	size_t nrecv = 0;
	ssize_t rv;
	while (nrecv < len) {
		rv = read(sd, p, len - nrecv);
		if (0 > rv)
			return -1;
		if (0 == rv)
			return 0;
		nrecv += rv;
		p += rv;
	}
	return nrecv;
}

int
continuesafe(struct ckpt_restore *cr)
{
	int i;
	char *p, *q;

	safe_cr = *cr;
	cr = 0; /* This pointer is in unsafe memory */
	for (i = 0; i < safe_cr.head.num_regions; i++) {
		if (safe_cr.orig_regions[i].len
		    != xread(safe_cr.fd,
			    (void *)safe_cr.orig_regions[i].addr,
			    safe_cr.orig_regions[i].len))
			return -1;
	}
	close(safe_cr.fd);

	/* copy the command */
	p = (char *)safe_cr.argv0;
	q = safe_cr.head.cmd;
	while (*q)
		*p++ = *q++;
	*p = '\0';

	longjmp(safe_cr.head.jbuf, 1);

	/* We shouldn't be here.  Don't return -- we don't have any
          idea what code we might return to.  It is easier to debug if
          we catch a segfault in here. */
	*((int *)0) = 0;  /* Die */
	return -1;
}