1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 #include <sys/ksyms.h>
30 #include <sys/systm.h>
31 #include <sys/sysmacros.h>
32 #include <sys/debug.h>
33 #include <sys/cmn_err.h>
34
35 static const char ksyms_shstrtab[] = "\0.symtab\0.strtab\0.shstrtab\0";
36
37 #define KSHDR_NULL 0
38 #define KSHDR_SYMTAB 1
39 #define KSHDR_STRTAB 2
40 #define KSHDR_SHSTRTAB 3
41 #define KSHDR_NUM 4
42
43 typedef struct ksyms_header {
44 Ehdr elf_hdr; /* Elf file header */
45 Phdr text_phdr; /* text program header */
46 Phdr data_phdr; /* data program header */
47 Shdr shdr[KSHDR_NUM]; /* section headers */
48 char shstrings[sizeof (ksyms_shstrtab)]; /* shstrtab strings */
49 } ksyms_header_t;
50
51 #define KW_HEADER 0x1
52 #define KW_LOCALS 0x2
53 #define KW_GLOBALS 0x4
54 #define KW_STRINGS 0x8
55
56 typedef struct ksyms_walkinfo {
57 void (*kw_emit)(const void *, void *, size_t);
58 char *kw_target;
59 ssize_t kw_resid;
60 ssize_t kw_totalsize;
61 int kw_actions;
62 size_t kw_size[KW_STRINGS + 1];
63 } ksyms_walkinfo_t;
64
65 krwlock_t ksyms_lock;
66 vmem_t *ksyms_arena;
67
68 static void
ksyms_emit(ksyms_walkinfo_t * kwp,void * src,size_t size,int action)69 ksyms_emit(ksyms_walkinfo_t *kwp, void *src, size_t size, int action)
70 {
71 if (kwp->kw_actions & action) {
72 if ((kwp->kw_resid -= size) >= 0)
73 kwp->kw_emit(src, kwp->kw_target, size);
74 kwp->kw_totalsize += size;
75 }
76 kwp->kw_size[action] += size;
77 }
78
79 /*ARGSUSED*/
80 static void
ksyms_walk_one(void * arg,void * base,size_t size)81 ksyms_walk_one(void *arg, void *base, size_t size)
82 {
83 ksyms_walkinfo_t *kwp = arg;
84 Shdr *symhdr = base;
85 Shdr *strhdr = symhdr + symhdr->sh_link;
86 size_t symsize = symhdr->sh_entsize;
87 size_t nsyms = symhdr->sh_size / symsize;
88 char *strings = (char *)strhdr->sh_addr;
89 int i;
90
91 for (i = 1; i < nsyms; i++) {
92 Sym *sym = (Sym *)(symhdr->sh_addr + i * symsize);
93 Sym tmp = *sym;
94 char *name = strings + sym->st_name;
95 tmp.st_name = kwp->kw_size[KW_STRINGS];
96 tmp.st_shndx = SHN_ABS;
97 ksyms_emit(kwp, &tmp, sizeof (Sym),
98 ELF_ST_BIND(sym->st_info) == STB_LOCAL ?
99 KW_LOCALS : KW_GLOBALS);
100 ksyms_emit(kwp, name, strlen(name) + 1, KW_STRINGS);
101 }
102 }
103
104 static ssize_t
ksyms_walk(ksyms_walkinfo_t * kwp,void * target,ssize_t resid,void (* emit)(const void *,void *,size_t),void * src,int actions)105 ksyms_walk(ksyms_walkinfo_t *kwp, void *target, ssize_t resid,
106 void (*emit)(const void *, void *, size_t), void *src, int actions)
107 {
108 Sym tmp;
109
110 bzero(kwp, sizeof (ksyms_walkinfo_t));
111 kwp->kw_emit = emit;
112 kwp->kw_target = target;
113 kwp->kw_resid = resid;
114 kwp->kw_actions = actions;
115
116 ksyms_emit(kwp, src, sizeof (ksyms_header_t), KW_HEADER);
117 /*
118 * The first symbol table entry is all zeroes; it's unused
119 * because index 0 marks the end of symbol hash chains.
120 */
121 bzero(&tmp, sizeof (Sym));
122 ksyms_emit(kwp, &tmp, sizeof (Sym), KW_LOCALS);
123 ksyms_emit(kwp, &tmp, 1, KW_STRINGS);
124 vmem_walk(ksyms_arena, VMEM_ALLOC, ksyms_walk_one, kwp);
125 return (kwp->kw_totalsize);
126 }
127
128 size_t
ksyms_snapshot(void (* emit)(const void *,void *,size_t),void * buf,size_t len)129 ksyms_snapshot(void (*emit)(const void *, void *, size_t),
130 void *buf, size_t len)
131 {
132 ksyms_walkinfo_t kw;
133 ksyms_header_t hdr;
134 ssize_t size = 0, bufsize = len;
135 Shdr *shp;
136
137 rw_enter(&ksyms_lock, RW_READER);
138
139 /*
140 * Compute the size of the header, locals, globals, and strings.
141 */
142 (void) ksyms_walk(&kw, NULL, 0, NULL, NULL,
143 KW_HEADER | KW_LOCALS | KW_GLOBALS | KW_STRINGS);
144
145 /*
146 * Construct the ELF header.
147 */
148 bzero(&hdr, sizeof (hdr));
149
150 hdr.elf_hdr = ((struct module *)modules.mod_mp)->hdr;
151 hdr.elf_hdr.e_phoff = offsetof(ksyms_header_t, text_phdr);
152 hdr.elf_hdr.e_shoff = offsetof(ksyms_header_t, shdr);
153 hdr.elf_hdr.e_phnum = 2;
154 hdr.elf_hdr.e_shnum = KSHDR_NUM;
155 hdr.elf_hdr.e_shstrndx = KSHDR_SHSTRTAB;
156
157 hdr.text_phdr.p_type = PT_LOAD;
158 hdr.text_phdr.p_vaddr = (Addr)s_text;
159 hdr.text_phdr.p_memsz = (Word)(e_text - s_text);
160 hdr.text_phdr.p_flags = PF_R | PF_X;
161
162 hdr.data_phdr.p_type = PT_LOAD;
163 hdr.data_phdr.p_vaddr = (Addr)s_data;
164 hdr.data_phdr.p_memsz = (Word)(e_data - s_data);
165 hdr.data_phdr.p_flags = PF_R | PF_W | PF_X;
166
167 shp = &hdr.shdr[KSHDR_SYMTAB];
168 shp->sh_name = 1; /* ksyms_shstrtab[1] = ".symtab" */
169 shp->sh_type = SHT_SYMTAB;
170 shp->sh_offset = kw.kw_size[KW_HEADER];
171 shp->sh_size = kw.kw_size[KW_LOCALS] + kw.kw_size[KW_GLOBALS];
172 shp->sh_link = KSHDR_STRTAB;
173 shp->sh_info = kw.kw_size[KW_LOCALS] / sizeof (Sym);
174 shp->sh_addralign = sizeof (Addr);
175 shp->sh_entsize = sizeof (Sym);
176
177 shp = &hdr.shdr[KSHDR_STRTAB];
178 shp->sh_name = 9; /* ksyms_shstrtab[9] = ".strtab" */
179 shp->sh_type = SHT_STRTAB;
180 shp->sh_offset = kw.kw_size[KW_HEADER] +
181 kw.kw_size[KW_LOCALS] + kw.kw_size[KW_GLOBALS];
182 shp->sh_size = kw.kw_size[KW_STRINGS];
183 shp->sh_addralign = 1;
184
185 shp = &hdr.shdr[KSHDR_SHSTRTAB];
186 shp->sh_name = 17; /* ksyms_shstrtab[17] = ".shstrtab" */
187 shp->sh_type = SHT_STRTAB;
188 shp->sh_offset = offsetof(ksyms_header_t, shstrings);
189 shp->sh_size = sizeof (ksyms_shstrtab);
190 shp->sh_addralign = 1;
191
192 bcopy(ksyms_shstrtab, hdr.shstrings, sizeof (ksyms_shstrtab));
193
194 /*
195 * Emit the symbol table.
196 */
197 size += ksyms_walk(&kw, buf, (bufsize - size), emit, &hdr,
198 KW_HEADER);
199 size += ksyms_walk(&kw, buf, (bufsize - size), emit,
200 NULL, KW_LOCALS);
201 size += ksyms_walk(&kw, buf, (bufsize - size), emit,
202 NULL, KW_GLOBALS);
203 size += ksyms_walk(&kw, buf, (bufsize - size), emit, NULL,
204 KW_STRINGS);
205
206 rw_exit(&ksyms_lock);
207
208 return ((size_t)size);
209 }
210