1 /* $OpenBSD: ksyms.c,v 1.17 2006/07/12 18:09:24 martin Exp $ */
2 /*
3 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
4 * Copyright (c) 2001 Artur Grabowski <art@openbsd.org>
5 * All rights reserved.
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 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
17 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
18 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
19 * THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include <sys/param.h>
29 #include <sys/buf.h>
30 #include <sys/exec.h>
31 #include <sys/systm.h>
32 #include <sys/uio.h>
33 #include <sys/malloc.h>
34 #include <sys/fcntl.h>
35 #include <sys/conf.h>
36
37 #include <uvm/uvm_extern.h>
38
39 #ifdef _NLIST_DO_ELF
40 #include <sys/exec_elf.h>
41 #endif
42
43 #include <machine/cpu.h>
44
45 extern char *esym; /* end of symbol table */
46 #if defined(__sparc64__) || defined(__mips__)
47 extern char *ssym; /* end of kernel */
48 #else
49 extern long end; /* end of kernel */
50 #endif
51
52 static caddr_t ksym_head;
53 static caddr_t ksym_syms;
54 static size_t ksym_head_size;
55 static size_t ksym_syms_size;
56
57 void ksymsattach(int);
58
59 /*
60 * We assume __LDPGSZ is a multiple of PAGE_SIZE (it is)
61 */
62
63 /*ARGSUSED*/
64 void
65 ksymsattach(num)
66 int num;
67 {
68
69 #if defined(__sparc64__) || defined(__mips__)
70 if (esym <= ssym) {
71 printf("/dev/ksyms: Symbol table not valid.\n");
72 return;
73 }
74 #else
75 if (esym <= (char *)&end) {
76 printf("/dev/ksyms: Symbol table not valid.\n");
77 return;
78 }
79 #endif
80
81 #ifdef _NLIST_DO_ELF
82 do {
83 #if defined(__sparc64__) || defined(__mips__)
84 caddr_t symtab = ssym;
85 #else
86 caddr_t symtab = (caddr_t)&end;
87 #endif
88 Elf_Ehdr *elf;
89 Elf_Shdr *shdr;
90 int i;
91
92 elf = (Elf_Ehdr *)symtab;
93 if (memcmp(elf->e_ident, ELFMAG, SELFMAG) != 0 ||
94 elf->e_ident[EI_CLASS] != ELFCLASS ||
95 elf->e_machine != ELF_TARG_MACH)
96 break;
97
98 shdr = (Elf_Shdr *)&symtab[elf->e_shoff];
99 for (i = 0; i < elf->e_shnum; i++) {
100 if (shdr[i].sh_type == SHT_SYMTAB) {
101 break;
102 }
103 }
104
105 /*
106 * No symbol table found.
107 */
108 if (i == elf->e_shnum)
109 break;
110
111 /*
112 * No additional header.
113 */
114 ksym_head_size = 0;
115 ksym_syms = symtab;
116 ksym_syms_size = (size_t)(esym - symtab);
117
118 return;
119 } while (0);
120 #endif
121
122 #ifdef _NLIST_DO_AOUT
123 {
124 /*
125 * a.out header.
126 * Fake up a struct exec.
127 * We only fill in the following non-zero entries:
128 * a_text - fake text segment (struct exec only)
129 * a_syms - size of symbol table
130 */
131 caddr_t symtab = (char *)(&end + 1);
132 struct exec *k1;
133
134 ksym_head_size = __LDPGSZ;
135 ksym_head = malloc(ksym_head_size, M_DEVBUF, M_NOWAIT);
136 if (ksym_head == NULL) {
137 printf("failed to allocate memory for /dev/ksyms\n");
138 return;
139 }
140 bzero(ksym_head, ksym_head_size);
141
142 k1 = (struct exec *)ksym_head;
143
144 N_SETMAGIC(*k1, ZMAGIC, MID_MACHINE, 0);
145 k1->a_text = __LDPGSZ;
146 k1->a_syms = end;
147
148 ksym_syms = symtab;
149 ksym_syms_size = (size_t)(esym - symtab);
150 }
151 #endif
152 }
153
154 /*ARGSUSED*/
155 int
156 ksymsopen(dev, flag, mode, p)
157 dev_t dev;
158 int flag, mode;
159 struct proc *p;
160 {
161
162 /* There are no non-zero minor devices */
163 if (minor(dev) != 0)
164 return (ENXIO);
165
166 /* This device is read-only */
167 if ((flag & FWRITE))
168 return (EPERM);
169
170 /* ksym_syms must be initialized */
171 if (ksym_syms == NULL)
172 return (ENXIO);
173
174 return (0);
175 }
176
177 /*ARGSUSED*/
178 int
179 ksymsclose(dev, flag, mode, p)
180 dev_t dev;
181 int flag, mode;
182 struct proc *p;
183 {
184
185 return (0);
186 }
187
188 /*ARGSUSED*/
189 int
190 ksymsread(dev, uio, flags)
191 dev_t dev;
192 struct uio *uio;
193 int flags;
194 {
195 int error;
196 size_t len;
197 caddr_t v;
198 size_t off;
199
200 while (uio->uio_resid > 0) {
201 if (uio->uio_offset >= ksym_head_size + ksym_syms_size)
202 break;
203
204 if (uio->uio_offset < ksym_head_size) {
205 v = ksym_head + uio->uio_offset;
206 len = ksym_head_size - uio->uio_offset;
207 } else {
208 off = uio->uio_offset - ksym_head_size;
209 v = ksym_syms + off;
210 len = ksym_syms_size - off;
211 }
212
213 if (len > uio->uio_resid)
214 len = uio->uio_resid;
215
216 if ((error = uiomove(v, len, uio)) != 0)
217 return (error);
218 }
219
220 return (0);
221 }
222
223 /* XXX - not yet */
224 #if 0
225 paddr_t
226 ksymsmmap(dev, off, prot)
227 dev_t dev;
228 off_t off;
229 int prot;
230 {
231 vaddr_t va;
232 paddr_t pa;
233
234 if (off < 0)
235 return (-1);
236 if (off >= ksym_head_size + ksym_syms_size)
237 return (-1);
238
239 if ((vaddr_t)off < ksym_head_size) {
240 va = (vaddr_t)ksym_head + off;
241 } else {
242 va = (vaddr_t)ksym_syms + off;
243 }
244
245 if (pmap_extract(pmap_kernel, va, &pa) == FALSE)
246 panic("ksymsmmap: unmapped page");
247
248 return atop(pa);
249 }
250 #endif