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 file *fp;
65 struct vnode *vp;
66 int error;
67
68 error = priv_check(curthread, PRIV_KMEM_READ);
69 if (error != 0)
70 return (error);
71
72 if (flags != 0)
73 return (EINVAL);
74
75 error = getvnode(curthread, fd, &cap_write_rights, &fp);
76 if (error != 0)
77 return (error);
78 vp = fp->f_vnode;
79
80 if ((fp->f_flag & FWRITE) == 0) {
81 error = EBADF;
82 goto drop;
83 }
84 error = livedump_start_vnode(vp, flags, compression);
85 if (error != 0)
86 goto drop;
87 drop:
88 fdrop(fp, curthread);
89 return (error);
90 #else
91 return (EOPNOTSUPP);
92 #endif /* MINIDUMP_PAGE_TRACKING == 1 */
93 }
94
95 int
livedump_start_vnode(struct vnode * vp,int flags,uint8_t compression)96 livedump_start_vnode(struct vnode *vp, int flags, uint8_t compression)
97 {
98 #if MINIDUMP_PAGE_TRACKING == 1
99 struct dumperinfo di, *livedi;
100 struct diocskerneldump_arg kda;
101 void *rl_cookie;
102 int error;
103
104 /* Set up a new dumper. */
105 bzero(&di, sizeof(di));
106 di.dumper_start = vnode_dumper_start;
107 di.dumper = vnode_dump;
108 di.dumper_hdr = vnode_write_headers;
109 di.blocksize = PAGE_SIZE; /* Arbitrary. */
110 di.maxiosize = MAXDUMPPGS * PAGE_SIZE;
111
112 bzero(&kda, sizeof(kda));
113 kda.kda_compression = compression;
114 error = dumper_create(&di, "livedump", &kda, &livedi);
115 if (error != 0)
116 return (error);
117
118 /* Only allow one livedump to proceed at a time. */
119 if (sx_try_xlock(&livedump_sx) == 0) {
120 dumper_destroy(livedi);
121 error = EBUSY;
122 return (error);
123 }
124
125 /* To be used by the callback functions. */
126 livedi->priv = vp;
127
128 /* Lock the entire file range and vnode. */
129 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
130 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
131
132 EVENTHANDLER_INVOKE(livedumper_start, &error);
133 if (error != 0)
134 goto out;
135
136 dump_savectx();
137 error = minidumpsys(livedi, true);
138
139 EVENTHANDLER_INVOKE(livedumper_finish);
140 out:
141 VOP_UNLOCK(vp);
142 vn_rangelock_unlock(vp, rl_cookie);
143 sx_xunlock(&livedump_sx);
144 dumper_destroy(livedi);
145 return (error);
146 #else
147 return (EOPNOTSUPP);
148 #endif /* MINIDUMP_PAGE_TRACKING == 1 */
149 }
150
151 int
vnode_dumper_start(struct dumperinfo * di,void * key,uint32_t keysize)152 vnode_dumper_start(struct dumperinfo *di, void *key, uint32_t keysize)
153 {
154
155 /* Always begin with an offset of zero. */
156 di->dumpoff = 0;
157
158 KASSERT(keysize == 0, ("encryption not supported for livedumps"));
159 return (0);
160 }
161
162 /*
163 * Callback from dumpsys() to dump a chunk of memory.
164 *
165 * Parameters:
166 * arg Opaque private pointer to vnode
167 * virtual Virtual address (where to read the data from)
168 * offset Offset from start of core file
169 * length Data length
170 *
171 * Return value:
172 * 0 on success
173 * errno on error
174 */
175 int
vnode_dump(void * arg,void * virtual,off_t offset,size_t length)176 vnode_dump(void *arg, void *virtual, off_t offset, size_t length)
177 {
178 struct vnode *vp;
179 int error = 0;
180
181 vp = arg;
182 MPASS(vp != NULL);
183 ASSERT_VOP_LOCKED(vp, __func__);
184
185 EVENTHANDLER_INVOKE(livedumper_dump, virtual, offset, length, &error);
186 if (error != 0)
187 return (error);
188
189 /* Done? */
190 if (virtual == NULL)
191 return (0);
192
193 error = vn_rdwr(UIO_WRITE, vp, virtual, length, offset, UIO_SYSSPACE,
194 IO_NODELOCKED, curthread->td_ucred, NOCRED, NULL, curthread);
195 if (error != 0)
196 uprintf("%s: error writing livedump block at offset %jx: %d\n",
197 __func__, (uintmax_t)offset, error);
198 return (error);
199 }
200
201 /*
202 * Callback from dumpsys() to write out the dump header, placed at the end.
203 */
204 int
vnode_write_headers(struct dumperinfo * di,struct kerneldumpheader * kdh)205 vnode_write_headers(struct dumperinfo *di, struct kerneldumpheader *kdh)
206 {
207 struct vnode *vp;
208 int error;
209 off_t offset;
210
211 vp = di->priv;
212 MPASS(vp != NULL);
213 ASSERT_VOP_LOCKED(vp, __func__);
214
215 /* Compensate for compression/encryption adjustment of dumpoff. */
216 offset = roundup2(di->dumpoff, di->blocksize);
217
218 /* Write the kernel dump header to the end of the file. */
219 error = vn_rdwr(UIO_WRITE, vp, kdh, sizeof(*kdh), offset,
220 UIO_SYSSPACE, IO_NODELOCKED, curthread->td_ucred, NOCRED, NULL,
221 curthread);
222 if (error != 0)
223 uprintf("%s: error writing livedump header: %d\n", __func__,
224 error);
225 return (error);
226 }
227