Add three hooks to the livedump process: before, after, and for each block of dumped data. This allows, for example, quiescing the system before the dump begins or protecting data of interest to ensure its consistency in the final output. Reviewed by: markj, kib (previous version) Reviewed by: debdrup (manpages) Reviewed by: Pau Amma <pauamma@gundo.com> (manpages) MFC after: 3 weeks Sponsored by: Juniper Networks, Inc. Sponsored by: Klara, Inc. Differential Revision: https://reviews.freebsd.org/D34067
214 lines
5.6 KiB
C
214 lines
5.6 KiB
C
/*-
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* Copyright (c) 2021-2022 Juniper Networks
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*
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* This software was developed by Mitchell Horne <mhorne@FreeBSD.org>
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* under sponsorship from Juniper Networks and Klara Systems.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/caprights.h>
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#include <sys/disk.h>
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#include <sys/eventhandler.h>
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#include <sys/fcntl.h>
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#include <sys/file.h>
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#include <sys/kerneldump.h>
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#include <sys/limits.h>
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#include <sys/malloc.h>
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#include <sys/namei.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/stat.h>
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#include <sys/sysctl.h>
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#include <sys/vnode.h>
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#include <machine/vmparam.h>
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static dumper_start_t vnode_dumper_start;
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static dumper_t vnode_dump;
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static dumper_hdr_t vnode_write_headers;
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static struct sx livedump_sx;
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SX_SYSINIT(livedump, &livedump_sx, "Livedump sx");
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/*
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* Invoke a live minidump on the system.
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*/
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int
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livedump_start(int fd, int flags, uint8_t compression)
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{
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#if MINIDUMP_PAGE_TRACKING == 1
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struct dumperinfo di, *livedi;
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struct diocskerneldump_arg kda;
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struct vnode *vp;
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struct file *fp;
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void *rl_cookie;
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int error;
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error = priv_check(curthread, PRIV_KMEM_READ);
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if (error != 0)
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return (error);
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if (flags != 0)
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return (EINVAL);
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error = getvnode(curthread, fd, &cap_write_rights, &fp);
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if (error != 0)
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return (error);
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vp = fp->f_vnode;
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if ((fp->f_flag & FWRITE) == 0) {
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error = EBADF;
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goto drop;
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}
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/* Set up a new dumper. */
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bzero(&di, sizeof(di));
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di.dumper_start = vnode_dumper_start;
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di.dumper = vnode_dump;
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di.dumper_hdr = vnode_write_headers;
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di.blocksize = PAGE_SIZE; /* Arbitrary. */
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di.maxiosize = MAXDUMPPGS * PAGE_SIZE;
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bzero(&kda, sizeof(kda));
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kda.kda_compression = compression;
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error = dumper_create(&di, "livedump", &kda, &livedi);
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if (error != 0)
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goto drop;
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/* Only allow one livedump to proceed at a time. */
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if (sx_try_xlock(&livedump_sx) == 0) {
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dumper_destroy(livedi);
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error = EBUSY;
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goto drop;
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}
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/* To be used by the callback functions. */
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livedi->priv = vp;
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/* Lock the entire file range and vnode. */
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rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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EVENTHANDLER_INVOKE(livedumper_start, &error);
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if (error != 0)
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goto out;
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dump_savectx();
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error = minidumpsys(livedi, true);
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EVENTHANDLER_INVOKE(livedumper_finish);
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out:
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VOP_UNLOCK(vp);
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vn_rangelock_unlock(vp, rl_cookie);
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sx_xunlock(&livedump_sx);
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dumper_destroy(livedi);
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drop:
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fdrop(fp, curthread);
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return (error);
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#else
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return (EOPNOTSUPP);
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#endif /* MINIDUMP_PAGE_TRACKING == 1 */
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}
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int
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vnode_dumper_start(struct dumperinfo *di, void *key, uint32_t keysize)
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{
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/* Always begin with an offset of zero. */
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di->dumpoff = 0;
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KASSERT(keysize == 0, ("encryption not supported for livedumps"));
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return (0);
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}
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/*
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* Callback from dumpsys() to dump a chunk of memory.
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*
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* Parameters:
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* arg Opaque private pointer to vnode
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* virtual Virtual address (where to read the data from)
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* physical Physical memory address (unused)
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* offset Offset from start of core file
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* length Data length
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*
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* Return value:
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* 0 on success
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* errno on error
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*/
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int
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vnode_dump(void *arg, void *virtual, vm_offset_t physical __unused,
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off_t offset, size_t length)
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{
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struct vnode *vp;
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int error = 0;
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vp = arg;
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MPASS(vp != NULL);
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ASSERT_VOP_LOCKED(vp, __func__);
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EVENTHANDLER_INVOKE(livedumper_dump, virtual, offset, length, &error);
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if (error != 0)
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return (error);
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/* Done? */
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if (virtual == NULL)
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return (0);
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error = vn_rdwr(UIO_WRITE, vp, virtual, length, offset, UIO_SYSSPACE,
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IO_NODELOCKED, curthread->td_ucred, NOCRED, NULL, curthread);
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if (error != 0)
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uprintf("%s: error writing livedump block at offset %jx: %d\n",
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__func__, (uintmax_t)offset, error);
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return (error);
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}
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/*
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* Callback from dumpsys() to write out the dump header, placed at the end.
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*/
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int
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vnode_write_headers(struct dumperinfo *di, struct kerneldumpheader *kdh)
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{
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struct vnode *vp;
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int error;
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off_t offset;
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vp = di->priv;
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MPASS(vp != NULL);
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ASSERT_VOP_LOCKED(vp, __func__);
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/* Compensate for compression/encryption adjustment of dumpoff. */
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offset = roundup2(di->dumpoff, di->blocksize);
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/* Write the kernel dump header to the end of the file. */
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error = vn_rdwr(UIO_WRITE, vp, kdh, sizeof(*kdh), offset,
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UIO_SYSSPACE, IO_NODELOCKED, curthread->td_ucred, NOCRED, NULL,
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curthread);
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if (error != 0)
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uprintf("%s: error writing livedump header: %d\n", __func__,
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error);
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return (error);
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}
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