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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2007 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 <stdlib.h>
30 #include <errno.h>
31 #include <fcntl.h>
32 #include <strings.h>
33 #include <stdio.h>
34 #include <sys/types.h>
35 #include <sys/inttypes.h>
36 #include <sys/elf.h>
37 #include <sys/elf_notes.h>
38 #include <sys/mman.h>
39 #include <sys/stat.h>
40 #include "sys/multiboot.h"
41
42 static char *pname;
43 static char *fname;
44 static char *image; /* pointer to the ELF file in memory */
45
46 #define ELFSEEK(offset) ((void *)(image + offset))
47
48 /*
49 * patch the load address / entry address
50 * Find the physical load address of the 1st PT_LOAD segment.
51 * Find the amount that e_entry exceeds that amount.
52 * Now go back and subtract the excess from the p_paddr of the LOAD segment.
53 */
54 static int
patch64(Elf64_Ehdr * eh)55 patch64(Elf64_Ehdr *eh)
56 {
57 Elf64_Phdr *phdr;
58 caddr_t phdrs = NULL;
59 int ndx, mem;
60 multiboot_header_t *mbh;
61
62 /*
63 * Verify some ELF basics - this must be an executable with program
64 * headers.
65 */
66 if (eh->e_type != ET_EXEC) {
67 (void) fprintf(stderr, "%s: %s: not ET_EXEC, e_type = 0x%x\n",
68 pname, fname, eh->e_type);
69 return (1);
70 }
71 if ((eh->e_phnum == 0) || (eh->e_phoff == 0)) {
72 (void) fprintf(stderr, "%s: %s: no program headers\n", pname,
73 fname);
74 return (1);
75 }
76
77 /*
78 * Get the program headers.
79 */
80 if ((phdrs = ELFSEEK(eh->e_phoff)) == NULL) {
81 (void) fprintf(stderr, "%s: %s: failed to get %d program "
82 "hdrs\n", pname, fname, eh->e_phnum);
83 return (1);
84 }
85
86 /*
87 * Look for multiboot header. It must be 32-bit aligned and
88 * completely contained in the 1st 8K of the file.
89 */
90 for (mem = 0; mem < 8192 - sizeof (multiboot_header_t); mem += 4) {
91 mbh = ELFSEEK(mem);
92 if (mbh->magic == MB_HEADER_MAGIC)
93 break;
94 }
95
96 if (mem >= 8192 - sizeof (multiboot_header_t)) {
97 (void) fprintf(stderr, "%s: %s: Didn't find multiboot header\n",
98 pname, fname);
99 return (1);
100 }
101
102 /*
103 * Find the 1:1 mapped PT_LOAD section
104 */
105 for (ndx = 0; ndx < eh->e_phnum; ndx++) {
106 /*LINTED [ELF program header alignment]*/
107 phdr = (Elf64_Phdr *)(phdrs + eh->e_phentsize * ndx);
108
109 /*
110 * Find the low memory 1:1 PT_LOAD section!
111 */
112 if (phdr->p_type != PT_LOAD)
113 continue;
114
115 if (phdr->p_memsz == 0)
116 continue;
117
118 if (phdr->p_paddr != phdr->p_vaddr)
119 continue;
120
121 /*
122 * Make sure the multiboot header is part of the first PT_LOAD
123 * segment, and that the executables entry point starts at the
124 * same segment.
125 */
126 if ((mem < phdr->p_offset) ||
127 (mem >= (phdr->p_offset + phdr->p_filesz))) {
128 (void) fprintf(stderr, "%s: %s: identity mapped "
129 "PT_LOAD wasn't 1st PT_LOAD\n", pname, fname);
130 return (1);
131 }
132 if (eh->e_entry != phdr->p_paddr) {
133 (void) fprintf(stderr, "%s: %s: entry != paddr\n",
134 pname, fname);
135 return (1);
136 }
137
138 /*
139 * Patch the multiboot header fields to get entire file loaded.
140 * Grub uses the MB header for 64 bit loading.
141 */
142 mbh->load_addr = phdr->p_paddr - phdr->p_offset;
143 mbh->entry_addr = phdr->p_paddr;
144 mbh->header_addr = mbh->load_addr + mem;
145 #ifdef VERBOSE
146 (void) printf(" %s: ELF64 MB header patched\n", fname);
147 (void) printf("\tload_addr now: 0x%x\n", mbh->load_addr);
148 (void) printf("\tentry_addr now: 0x%x\n", mbh->entry_addr);
149 (void) printf("\theader_addr now: 0x%x\n", mbh->header_addr);
150 #endif
151 return (0);
152 }
153
154 (void) fprintf(stderr, "%s: %s: Didn't find 1:1 mapped PT_LOAD "
155 "section\n", pname, fname);
156 return (1);
157 }
158
159 int
main(int argc,char ** argv)160 main(int argc, char **argv)
161 {
162 int fd;
163 uchar_t *ident;
164 void *hdr = NULL;
165
166 /*
167 * we expect one argument -- the elf file
168 */
169 if (argc != 2) {
170 (void) fprintf(stderr, "usage: %s <unix-elf-file>\n", argv[0]);
171 return (1);
172 }
173
174 pname = strrchr(argv[0], '/');
175 if (pname == NULL)
176 pname = argv[0];
177 else
178 ++pname;
179
180 fname = argv[1];
181 if ((fd = open(fname, O_RDWR)) < 0) {
182 (void) fprintf(stderr, "%s: open(%s, O_RDWR) failed: %s\n",
183 pname, fname, strerror(errno));
184 return (1);
185 }
186
187 /*
188 * mmap just the 1st 8K -- since that's where the GRUB
189 * multiboot header must be located.
190 */
191 image = mmap(NULL, 8192, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
192 if (image == MAP_FAILED) {
193 (void) fprintf(stderr, "%s: mmap() of %s failed: %s\n",
194 pname, fname, strerror(errno));
195 return (1);
196 }
197
198 ident = ELFSEEK(0);
199 if (ident[EI_MAG0] != ELFMAG0 || ident[EI_MAG1] != ELFMAG1 ||
200 ident[EI_MAG2] != ELFMAG2 || ident[EI_MAG3] != ELFMAG3) {
201 (void) fprintf(stderr, "%s: %s: not an ELF file!\n", pname,
202 fname);
203 return (1);
204 }
205
206 if (ident[EI_CLASS] == ELFCLASS64) {
207 hdr = ELFSEEK(0);
208 return (patch64(hdr));
209 }
210 if (ident[EI_CLASS] != ELFCLASS32) {
211 (void) fprintf(stderr, "%s: Unknown ELF class 0x%x\n", pname,
212 ident[EI_CLASS]);
213 return (1);
214 }
215 return (0);
216 }
217