1 /*-
2 * Copyright (c) 2021-2022 Juniper Networks
3 *
4 * This software was developed by Mitchell Horne <mhorne@FreeBSD.org>
5 * under sponsorship from Juniper Networks and Klara Systems.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/conf.h>
32 #include <sys/caprights.h>
33 #include <sys/disk.h>
34 #include <sys/eventhandler.h>
35 #include <sys/fcntl.h>
36 #include <sys/file.h>
37 #include <sys/kerneldump.h>
38 #include <sys/limits.h>
39 #include <sys/malloc.h>
40 #include <sys/namei.h>
41 #include <sys/priv.h>
42 #include <sys/proc.h>
43 #include <sys/stat.h>
44 #include <sys/sysctl.h>
45 #include <sys/vnode.h>
46
47 #include <machine/pcb.h>
48 #include <machine/vmparam.h>
49
50 static dumper_start_t vnode_dumper_start;
51 static dumper_t vnode_dump;
52 static dumper_hdr_t vnode_write_headers;
53
54 static struct sx livedump_sx;
55 SX_SYSINIT(livedump, &livedump_sx, "Livedump sx");
56
57 /*
58 * Invoke a live minidump on the system.
59 */
60 int
livedump_start(int fd,int flags,uint8_t compression)61 livedump_start(int fd, int flags, uint8_t compression)
62 {
63 #if MINIDUMP_PAGE_TRACKING == 1
64 struct dumperinfo di, *livedi;
65 struct diocskerneldump_arg kda;
66 struct vnode *vp;
67 struct file *fp;
68 void *rl_cookie;
69 int error;
70
71 error = priv_check(curthread, PRIV_KMEM_READ);
72 if (error != 0)
73 return (error);
74
75 if (flags != 0)
76 return (EINVAL);
77
78 error = getvnode(curthread, fd, &cap_write_rights, &fp);
79 if (error != 0)
80 return (error);
81 vp = fp->f_vnode;
82
83 if ((fp->f_flag & FWRITE) == 0) {
84 error = EBADF;
85 goto drop;
86 }
87
88 /* Set up a new dumper. */
89 bzero(&di, sizeof(di));
90 di.dumper_start = vnode_dumper_start;
91 di.dumper = vnode_dump;
92 di.dumper_hdr = vnode_write_headers;
93 di.blocksize = PAGE_SIZE; /* Arbitrary. */
94 di.maxiosize = MAXDUMPPGS * PAGE_SIZE;
95
96 bzero(&kda, sizeof(kda));
97 kda.kda_compression = compression;
98 error = dumper_create(&di, "livedump", &kda, &livedi);
99 if (error != 0)
100 goto drop;
101
102 /* Only allow one livedump to proceed at a time. */
103 if (sx_try_xlock(&livedump_sx) == 0) {
104 dumper_destroy(livedi);
105 error = EBUSY;
106 goto drop;
107 }
108
109 /* To be used by the callback functions. */
110 livedi->priv = vp;
111
112 /* Lock the entire file range and vnode. */
113 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
114 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
115
116 EVENTHANDLER_INVOKE(livedumper_start, &error);
117 if (error != 0)
118 goto out;
119
120 dump_savectx();
121 error = minidumpsys(livedi, true);
122
123 EVENTHANDLER_INVOKE(livedumper_finish);
124 out:
125 VOP_UNLOCK(vp);
126 vn_rangelock_unlock(vp, rl_cookie);
127 sx_xunlock(&livedump_sx);
128 dumper_destroy(livedi);
129 drop:
130 fdrop(fp, curthread);
131 return (error);
132 #else
133 return (EOPNOTSUPP);
134 #endif /* MINIDUMP_PAGE_TRACKING == 1 */
135 }
136
137 int
vnode_dumper_start(struct dumperinfo * di,void * key,uint32_t keysize)138 vnode_dumper_start(struct dumperinfo *di, void *key, uint32_t keysize)
139 {
140
141 /* Always begin with an offset of zero. */
142 di->dumpoff = 0;
143
144 KASSERT(keysize == 0, ("encryption not supported for livedumps"));
145 return (0);
146 }
147
148 /*
149 * Callback from dumpsys() to dump a chunk of memory.
150 *
151 * Parameters:
152 * arg Opaque private pointer to vnode
153 * virtual Virtual address (where to read the data from)
154 * offset Offset from start of core file
155 * length Data length
156 *
157 * Return value:
158 * 0 on success
159 * errno on error
160 */
161 int
vnode_dump(void * arg,void * virtual,off_t offset,size_t length)162 vnode_dump(void *arg, void *virtual, off_t offset, size_t length)
163 {
164 struct vnode *vp;
165 int error = 0;
166
167 vp = arg;
168 MPASS(vp != NULL);
169 ASSERT_VOP_LOCKED(vp, __func__);
170
171 EVENTHANDLER_INVOKE(livedumper_dump, virtual, offset, length, &error);
172 if (error != 0)
173 return (error);
174
175 /* Done? */
176 if (virtual == NULL)
177 return (0);
178
179 error = vn_rdwr(UIO_WRITE, vp, virtual, length, offset, UIO_SYSSPACE,
180 IO_NODELOCKED, curthread->td_ucred, NOCRED, NULL, curthread);
181 if (error != 0)
182 uprintf("%s: error writing livedump block at offset %jx: %d\n",
183 __func__, (uintmax_t)offset, error);
184 return (error);
185 }
186
187 /*
188 * Callback from dumpsys() to write out the dump header, placed at the end.
189 */
190 int
vnode_write_headers(struct dumperinfo * di,struct kerneldumpheader * kdh)191 vnode_write_headers(struct dumperinfo *di, struct kerneldumpheader *kdh)
192 {
193 struct vnode *vp;
194 int error;
195 off_t offset;
196
197 vp = di->priv;
198 MPASS(vp != NULL);
199 ASSERT_VOP_LOCKED(vp, __func__);
200
201 /* Compensate for compression/encryption adjustment of dumpoff. */
202 offset = roundup2(di->dumpoff, di->blocksize);
203
204 /* Write the kernel dump header to the end of the file. */
205 error = vn_rdwr(UIO_WRITE, vp, kdh, sizeof(*kdh), offset,
206 UIO_SYSSPACE, IO_NODELOCKED, curthread->td_ucred, NOCRED, NULL,
207 curthread);
208 if (error != 0)
209 uprintf("%s: error writing livedump header: %d\n", __func__,
210 error);
211 return (error);
212 }
213