Function core_output

freebsd/kern/imgact_elf.c:1545–1615

}

static int
core_output(char *base, size_t len, off_t offset, struct coredump_params *p,
    void *tmpbuf)
{
	vm_map_t map;
	struct mount *mp;
	size_t resid, runlen;
	int error;
	bool success;

	KASSERT((uintptr_t)base % PAGE_SIZE == 0,
	    ("%s: user address %p is not page-aligned", __func__, base));

	if (p->comp != NULL)
		return (compress_chunk(p, base, tmpbuf, len));

	map = &p->td->td_proc->p_vmspace->vm_map;
	for (; len > 0; base += runlen, offset += runlen, len -= runlen) {
		/*
		 * Attempt to page in all virtual pages in the range.  If a
		 * virtual page is not backed by the pager, it is represented as
		 * a hole in the file.  This can occur with zero-filled
		 * anonymous memory or truncated files, for example.
		 */
		for (runlen = 0; runlen < len; runlen += PAGE_SIZE) {
			error = vm_fault(map, (uintptr_t)base + runlen,
			    VM_PROT_READ, VM_FAULT_NOFILL, NULL);
			if (runlen == 0)
				success = error == KERN_SUCCESS;
			else if ((error == KERN_SUCCESS) != success)
				break;
		}

		if (success) {
			error = core_write(p, base, runlen, offset,
			    UIO_USERSPACE, &resid);
			if (error != 0) {
				if (error != EFAULT)
					break;

				/*
				 * EFAULT may be returned if the user mapping
				 * could not be accessed, e.g., because a mapped
				 * file has been truncated.  Skip the page if no
				 * progress was made, to protect against a
				 * hypothetical scenario where vm_fault() was
				 * successful but core_write() returns EFAULT
				 * anyway.
				 */
				runlen -= resid;
				if (runlen == 0) {
					success = false;
					runlen = PAGE_SIZE;
				}
			}
		}
		if (!success) {
			error = vn_start_write(p->vp, &mp, V_WAIT);