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Index: sys/kern/imgact_elf.c
===================================================================
--- sys/kern/imgact_elf.c
+++ sys/kern/imgact_elf.c
@@ -1459,7 +1459,7 @@
static void cb_put_phdr(vm_map_entry_t, void *);
static void cb_size_segment(vm_map_entry_t, void *);
static int core_write(struct coredump_params *, const void *, size_t, off_t,
- enum uio_seg);
+ enum uio_seg, size_t *);
static void each_dumpable_segment(struct thread *, segment_callback, void *);
static int __elfN(corehdr)(struct coredump_params *, int, void *, size_t,
struct note_info_list *, size_t);
@@ -1519,46 +1519,88 @@
{
return (core_write((struct coredump_params *)arg, base, len, offset,
- UIO_SYSSPACE));
+ UIO_SYSSPACE, NULL));
}
static int
core_write(struct coredump_params *p, const void *base, size_t len,
- off_t offset, enum uio_seg seg)
+ off_t offset, enum uio_seg seg, size_t *resid)
{
return (vn_rdwr_inchunks(UIO_WRITE, p->vp, __DECONST(void *, base),
len, offset, seg, IO_UNIT | IO_DIRECT | IO_RANGELOCKED,
- p->active_cred, p->file_cred, NULL, p->td));
+ p->active_cred, p->file_cred, resid, p->td));
}
static int
-core_output(void *base, size_t len, off_t offset, struct coredump_params *p,
+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 %#lx is not page-aligned",
+ __func__, (uintptr_t)base));
if (p->comp != NULL)
return (compress_chunk(p, base, tmpbuf, len));
- /*
- * EFAULT is a non-fatal error that we can get, for example,
- * if the segment is backed by a file but extends beyond its
- * end.
- */
- error = core_write(p, base, len, offset, UIO_USERSPACE);
- if (error == EFAULT) {
- log(LOG_WARNING, "Failed to fully fault in a core file segment "
- "at VA %p with size 0x%zx to be written at offset 0x%jx "
- "for process %s\n", base, len, offset, curproc->p_comm);
-
+ map = &p->td->td_proc->p_vmspace->vm_map;
+ for (; len > 0; base += runlen, offset += runlen, len -= runlen) {
/*
- * Write a "real" zero byte at the end of the target region
- * in the case this is the last segment.
- * The intermediate space will be implicitly zero-filled.
+ * 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.
*/
- error = core_write(p, zero_region, 1, offset + len - 1,
- UIO_SYSSPACE);
+ 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);
+ if (error != 0)
+ break;
+ vn_lock(p->vp, LK_EXCLUSIVE | LK_RETRY);
+ error = vn_truncate_locked(p->vp, offset + runlen,
+ false, p->td->td_ucred);
+ VOP_UNLOCK(p->vp);
+ vn_finished_write(mp);
+ if (error != 0)
+ break;
+ }
}
return (error);
}
@@ -1589,7 +1631,7 @@
error = compressor_write(p->comp, __DECONST(char *, data), len);
else
error = core_write(p, __DECONST(void *, data), len, p->offset,
- UIO_SYSSPACE);
+ UIO_SYSSPACE, NULL);
if (locked)
PROC_LOCK(p->td->td_proc);
if (error != 0)
@@ -1681,7 +1723,7 @@
php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1;
offset = round_page(hdrsize + notesz);
for (i = 0; i < seginfo.count; i++) {
- error = core_output((caddr_t)(uintptr_t)php->p_vaddr,
+ error = core_output((char *)(uintptr_t)php->p_vaddr,
php->p_filesz, offset, &params, tmpbuf);
if (error != 0)
break;
Index: sys/vm/vm_fault.c
===================================================================
--- sys/vm/vm_fault.c
+++ sys/vm/vm_fault.c
@@ -1476,6 +1476,12 @@
*/
if (vm_fault_next(&fs))
continue;
+ if ((fs.fault_flags & VM_FAULT_NOFILL) != 0) {
+ if (fs.first_object == fs.object)
+ fault_page_free(&fs.first_m);
+ unlock_and_deallocate(&fs);
+ return (KERN_RESTART);
+ }
VM_OBJECT_WUNLOCK(fs.object);
vm_fault_zerofill(&fs);
/* Don't try to prefault neighboring pages. */
Index: sys/vm/vm_map.h
===================================================================
--- sys/vm/vm_map.h
+++ sys/vm/vm_map.h
@@ -384,9 +384,10 @@
/*
* vm_fault option flags
*/
-#define VM_FAULT_NORMAL 0 /* Nothing special */
-#define VM_FAULT_WIRE 1 /* Wire the mapped page */
-#define VM_FAULT_DIRTY 2 /* Dirty the page; use w/VM_PROT_COPY */
+#define VM_FAULT_NORMAL 0x00 /* Nothing special */
+#define VM_FAULT_WIRE 0x01 /* Wire the mapped page */
+#define VM_FAULT_DIRTY 0x02 /* Dirty the page; use w/VM_PROT_COPY */
+#define VM_FAULT_NOFILL 0x04 /* Fail if the pager doesn't have a copy */
/*
* Initially, mappings are slightly sequential. The maximum window size must

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