xref: /illumos-gate/usr/src/tools/elfextract/elfextract.c (revision bde334a8dbd66dfa70ce4d7fc9dcad6e1ae45fe4)
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 /*
28  * Copyright (c) 2018, Joyent, Inc.
29  */
30 
31 #include <unistd.h>
32 #include <stdlib.h>
33 #include <fcntl.h>
34 #include <strings.h>
35 #include <stdio.h>
36 #include <errno.h>
37 #include <sys/types.h>
38 #include <sys/inttypes.h>
39 #include <sys/elf.h>
40 #include <sys/elf_notes.h>
41 #include <sys/mman.h>
42 #include <sys/stat.h>
43 #include <sys/statvfs.h>
44 
45 static char *pname;
46 static char *fname;
47 static char *image;	/* pointer to the ELF file in memory */
48 
49 #define	ELFSEEK(offset) ((void *)(image + offset))
50 
51 /*
52  * Extract the PT_LOAD bits and format them into a .s
53  */
54 static void
55 extract32(Elf32_Ehdr *eh)
56 {
57 	Elf32_Phdr *phdr;
58 	caddr_t allphdrs;
59 	int i;
60 	int c;
61 	unsigned char *bytes;
62 	uint_t cnt = 10;
63 
64 	allphdrs = NULL;
65 
66 	if (eh->e_type != ET_EXEC) {
67 		(void) fprintf(stderr, "%s: not ET_EXEC, e_type = 0x%x\n",
68 		    pname, eh->e_type);
69 		exit(1);
70 	}
71 	if (eh->e_phnum == 0 || eh->e_phoff == 0) {
72 		(void) fprintf(stderr, "%s: no program headers\n", pname);
73 		exit(1);
74 	}
75 
76 	/*
77 	 * Get the program headers.
78 	 */
79 	allphdrs = ELFSEEK(eh->e_phoff);
80 	if (allphdrs == NULL) {
81 		(void) fprintf(stderr, "%s: Failed to get %d program hdrs\n",
82 		    pname, eh->e_phnum);
83 		exit(1);
84 	}
85 
86 	/*
87 	 * Find the PT_LOAD section
88 	 */
89 	for (i = 0; i < eh->e_phnum; i++) {
90 		/*LINTED [ELF program header alignment]*/
91 		phdr = (Elf32_Phdr *)(allphdrs + eh->e_phentsize * i);
92 
93 		if (phdr->p_type != PT_LOAD)
94 			continue;
95 
96 		if (phdr->p_memsz == 0)
97 			continue;
98 
99 		bytes = ELFSEEK(phdr->p_offset);
100 		for (c = 0; c < phdr->p_filesz; ++c) {
101 			if (c % cnt == 0)
102 				(void) printf("\n	.byte	");
103 			else
104 				(void) printf(",");
105 			(void) printf("0x%x", bytes[c]);
106 		}
107 		for (; c < phdr->p_memsz; ++c) {
108 			if (c % cnt == 0) {
109 				(void) printf("\n	.byte	");
110 				cnt = 20;
111 			} else {
112 				(void) printf(", ");
113 			}
114 			(void) printf("0");
115 		}
116 		(void) printf("\n");
117 		return;
118 	}
119 
120 	(void) fprintf(stderr, "%s: Failed finding PT_LOAD section\n", pname);
121 	exit(1);
122 }
123 
124 static void
125 extract64(Elf64_Ehdr *eh)
126 {
127 	Elf64_Phdr *phdr;
128 	caddr_t allphdrs;
129 	int i;
130 	int c;
131 	unsigned char *bytes;
132 	uint_t cnt = 10;
133 
134 	allphdrs = NULL;
135 
136 	if (eh->e_type != ET_EXEC) {
137 		(void) fprintf(stderr, "%s: not ET_EXEC, e_type = 0x%x\n",
138 		    pname, eh->e_type);
139 		exit(1);
140 	}
141 	if (eh->e_phnum == 0 || eh->e_phoff == 0) {
142 		(void) fprintf(stderr, "%s: no program headers\n", pname);
143 		exit(1);
144 	}
145 
146 	/*
147 	 * Get the program headers.
148 	 */
149 	allphdrs = ELFSEEK(eh->e_phoff);
150 	if (allphdrs == NULL) {
151 		(void) fprintf(stderr, "%s: Failed to get %d program hdrs\n",
152 		    pname, eh->e_phnum);
153 		exit(1);
154 	}
155 
156 	/*
157 	 * Find the PT_LOAD section
158 	 */
159 	for (i = 0; i < eh->e_phnum; i++) {
160 		/*LINTED [ELF program header alignment]*/
161 		phdr = (Elf64_Phdr *)(allphdrs + eh->e_phentsize * i);
162 
163 		if (phdr->p_type != PT_LOAD)
164 			continue;
165 
166 		if (phdr->p_memsz == 0)
167 			continue;
168 
169 		bytes = ELFSEEK(phdr->p_offset);
170 		for (c = 0; c < phdr->p_filesz; ++c) {
171 			if (c % cnt == 0)
172 				(void) printf("\n	.byte	");
173 			else
174 				(void) printf(",");
175 			(void) printf("0x%x", bytes[c]);
176 		}
177 		for (; c < phdr->p_memsz; ++c) {
178 			if (c % cnt == 0) {
179 				(void) printf("\n	.byte	");
180 				cnt = 20;
181 			} else {
182 				(void) printf(", ");
183 			}
184 			(void) printf("0");
185 		}
186 		(void) printf("\n");
187 		return;
188 	}
189 
190 	(void) fprintf(stderr, "%s: Failed finding PT_LOAD section\n", pname);
191 	exit(1);
192 }
193 
194 int
195 main(int argc, char **argv)
196 {
197 	int fd;
198 	uchar_t *ident;
199 	void *hdr = NULL;
200 	struct stat stats;
201 	ssize_t r;
202 	size_t pgsz;
203 	uint_t len;
204 
205 	/*
206 	 * we expect one argument -- the elf file
207 	 */
208 	if (argc != 2) {
209 		(void) fprintf(stderr, "usage: %s <unix-elf-file>\n", argv[0]);
210 		exit(1);
211 	}
212 
213 	pname = strrchr(argv[0], '/');
214 	if (pname == NULL)
215 		pname = argv[0];
216 	else
217 		++pname;
218 
219 	fname = argv[1];
220 	fd = open(fname, O_RDONLY);
221 	if (fd < 0) {
222 		(void) fprintf(stderr, "%s: open(%s, O_RDONLY) failed, %s\n",
223 		    pname, fname, strerror(errno));
224 		exit(1);
225 	}
226 
227 	if (stat(fname, &stats) < 0) {
228 		(void) fprintf(stderr, "%s: stat(%s, ...) failed, %s\n",
229 		    pname, fname, strerror(errno));
230 		exit(1);
231 	}
232 
233 	pgsz = getpagesize();
234 	len = (stats.st_size + (pgsz - 1)) & (~(pgsz - 1));
235 
236 	/*
237 	 * mmap the file
238 	 */
239 	image = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, 0);
240 	if (image == MAP_FAILED) {
241 		(void) fprintf(stderr, "%s: mmap() of %s failed, %s\n",
242 		    pname, fname, strerror(errno));
243 		exit(1);
244 	}
245 
246 	ident = ELFSEEK(0);
247 	if (ident[EI_MAG0] != ELFMAG0 || ident[EI_MAG1] != ELFMAG1 ||
248 	    ident[EI_MAG2] != ELFMAG2 || ident[EI_MAG3] != ELFMAG3) {
249 		(void) fprintf(stderr, "%s: not an ELF file!\n", pname);
250 		exit(1);
251 	}
252 
253 	if (ident[EI_CLASS] == ELFCLASS32) {
254 		hdr = ELFSEEK(0);
255 		extract32(hdr);
256 	} else if (ident[EI_CLASS] == ELFCLASS64) {
257 		hdr = ELFSEEK(0);
258 		extract64(hdr);
259 	} else {
260 		(void) fprintf(stderr, "%s: Wrong ELF class 0x%x\n", pname,
261 		    ident[EI_CLASS]);
262 		exit(1);
263 	}
264 	return (0);
265 }
266