1 /* $NetBSD: elf.c,v 1.14 2011/10/01 15:59:00 chs Exp $ */
2
3 /*-
4 * Copyright (c) 1998 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Leo Weppelman.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #ifdef TOSTOOLS
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <unistd.h>
36 #include <string.h>
37 #include <sys/types.h>
38 #include "exec_elf.h"
39
40 #define MALLOC(x) malloc(x)
41
42 #else
43
44 #include <lib/libsa/stand.h>
45 #include <atari_stand.h>
46 #include <libkern.h>
47 #include <sys/exec_elf.h>
48
49 #define MALLOC(x) alloc(x)
50 #endif
51
52 #include "libtos.h"
53 #include "tosdefs.h"
54 #include "kparamb.h"
55 #include "cread.h"
56
57 /*
58 * Load an elf image.
59 * Exit codes:
60 * -1 : Not an ELF file.
61 * 0 : OK
62 * error# : Error during load (*errp might contain error string).
63 */
64 #define ELFMAGIC ((ELFMAG0 << 24) | (ELFMAG1 << 16) | \
65 (ELFMAG2 << 8) | ELFMAG3)
66
67 int
elf_load(int fd,osdsc_t * od,char ** errp,int loadsyms)68 elf_load(int fd, osdsc_t *od, char **errp, int loadsyms)
69 {
70 int i,j;
71 int err;
72 Elf32_Ehdr ehdr;
73 Elf32_Phdr *phdrs;
74 Elf32_Word ident, symsize, symstart;
75 long kernsize;
76
77 *errp = NULL;
78 lseek(fd, (off_t)0, SEEK_SET);
79 if (read(fd, (char *)&ehdr, sizeof(ehdr)) != sizeof(ehdr))
80 return -1;
81
82 memcpy(&ident, ehdr.e_ident, sizeof ident);
83 if (ident != ELFMAGIC)
84 return -1;
85
86 /*
87 * calculate highest used address
88 */
89 i = ehdr.e_phnum * sizeof(Elf32_Phdr);
90 err = 1;
91 if ((phdrs = (Elf32_Phdr *)MALLOC(i)) == NULL)
92 goto error;
93 err = 2;
94 if (read(fd, phdrs, i) != i)
95 goto error;
96
97 kernsize = 0;
98 for (i = 0; i < ehdr.e_phnum; i++) {
99 Elf32_Word sum;
100
101 sum = phdrs[i].p_vaddr + phdrs[i].p_memsz;
102 if ((phdrs[i].p_flags & (PF_W|PF_X)) && (sum > kernsize))
103 kernsize = sum;
104 }
105
106 /*
107 * look for symbols and calculate the size
108 * XXX: This increases the load time by a factor 2 for gzipped
109 * images!
110 */
111 symsize = 0;
112 symstart = 0;
113 if (loadsyms) {
114 i = ehdr.e_shnum + 1;
115 err = 3;
116 if (lseek(fd, (off_t)ehdr.e_shoff, SEEK_SET) != ehdr.e_shoff)
117 goto error;
118 while (--i) {
119 Elf32_Shdr shdr;
120
121 err = 4;
122 if (read(fd, &shdr, sizeof(shdr)) != sizeof(shdr))
123 goto error;
124 if ((shdr.sh_type == SHT_SYMTAB) || (shdr.sh_type == SHT_STRTAB))
125 symsize += shdr.sh_size;
126 }
127 }
128
129 if (symsize) {
130 symstart = kernsize;
131 kernsize += symsize + sizeof(ehdr) + ehdr.e_shnum*sizeof(Elf32_Shdr);
132 }
133
134 /*
135 * Extract various sizes from the kernel executable
136 */
137 od->k_esym = symsize ? kernsize : 0;
138 od->ksize = kernsize;
139 od->kentry = ehdr.e_entry;
140
141 err = 5;
142 if ((od->kstart = (u_char *)MALLOC(od->ksize)) == NULL)
143 goto error;
144
145 /*
146 * Read text & data, clear bss
147 */
148 for (i = 0; i < ehdr.e_phnum; i++) {
149 u_char *p;
150 Elf32_Phdr *php = &phdrs[i];
151
152 if (php->p_flags & (PF_W|PF_X)) {
153 err = 6;
154 if (lseek(fd, (off_t)php->p_offset, SEEK_SET) != php->p_offset)
155 goto error;
156 p = (u_char *)(od->kstart) + php->p_vaddr;
157 err = 7;
158 if (read(fd, p, php->p_filesz) != php->p_filesz)
159 goto error;
160 if (php->p_memsz > php->p_filesz)
161 memset(p + php->p_filesz, 0, php->p_memsz - php->p_filesz);
162 }
163 }
164
165 /*
166 * Read symbols and strings
167 */
168 if (symsize) {
169 u_char *p, *symtab;
170 int nhdrs;
171 Elf32_Shdr *shp;
172
173 symtab = od->kstart + symstart;
174
175 p = symtab + sizeof(ehdr);
176 nhdrs = ehdr.e_shnum;
177 err = 8;
178 if (lseek(fd, (off_t)ehdr.e_shoff, SEEK_SET) != ehdr.e_shoff)
179 goto error;
180 err = 9;
181 if (read(fd, p, nhdrs * sizeof(*shp)) != nhdrs * sizeof(*shp))
182 goto error;
183 shp = (Elf32_Shdr*)p;
184 p += nhdrs * sizeof(*shp);
185 for (i = 0; i < nhdrs; i++) {
186 if (shp[i].sh_type == SHT_SYMTAB) {
187 if (shp[i].sh_offset == 0)
188 continue;
189 /* Got the symbol table. */
190 err = 10;
191 if (lseek(fd, (off_t)shp[i].sh_offset, SEEK_SET) !=
192 shp[i].sh_offset)
193 goto error;
194 err = 11;
195 if (read(fd, p, shp[i].sh_size) != shp[i].sh_size)
196 goto error;
197 shp[i].sh_offset = p - symtab;
198 /* Find the string table to go with it. */
199 j = shp[i].sh_link;
200 if (shp[j].sh_offset == 0)
201 continue;
202 p += shp[i].sh_size;
203 err = 12;
204 if (lseek(fd, (off_t)shp[j].sh_offset, SEEK_SET) !=
205 shp[j].sh_offset)
206 goto error;
207 err = 13;
208 if (read(fd, p, shp[j].sh_size) != shp[j].sh_size)
209 goto error;
210 shp[j].sh_offset = p - symtab;
211 /* There should only be one symbol table. */
212 break;
213 }
214 }
215 ehdr.e_shoff = sizeof(ehdr);
216 memcpy(symtab, &ehdr, sizeof(ehdr));
217 }
218 return 0;
219
220 error:
221 #ifdef TOSTOOLS
222 {
223 static char *errs[] = {
224 /* 1 */ "Cannot malloc Elf phdr storage space",
225 /* 2 */ "Cannot read Elf32_Phdrs",
226 /* 3 */ "Cannot seek to e_shoff location",
227 /* 4 */ "Cannot read Elf32_shdr",
228 /* 5 */ "Cannot malloc kernel image space",
229 /* 6 */ "Seek error while reading text segment\n",
230 /* 7 */ "Read error in text segment\n",
231 /* 8 */ "Error seeking to section headers",
232 /* 9 */ "Error reading section headers",
233 /* 10 */ "Error seeking to symbols",
234 /* 11 */ "Error reading symbols",
235 /* 12 */ "Error seeking to string table",
236 /* 13 */ "Error reading strings"
237 };
238 *errp = errs[err];
239 }
240 #endif /* TOSTOOLS */
241
242 return err;
243 }
244