xref: /freebsd-12.1/usr.bin/elf2aout/elf2aout.c (revision 1de7b4b8)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2002 Jake Burkholder
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 BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/types.h>
33 #include <sys/elf64.h>
34 #include <sys/endian.h>
35 #include <sys/mman.h>
36 #include <sys/stat.h>
37 
38 #include <err.h>
39 #include <fcntl.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44 
45 #define	xe16toh(x)	((data == ELFDATA2MSB) ? be16toh(x) : le16toh(x))
46 #define	xe32toh(x)	((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
47 #define	xe64toh(x)	((data == ELFDATA2MSB) ? be64toh(x) : le64toh(x))
48 #define	htoxe32(x)	((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
49 
50 struct exec {
51 	u_int32_t	a_magic;
52 	u_int32_t	a_text;
53 	u_int32_t	a_data;
54 	u_int32_t	a_bss;
55 	u_int32_t	a_syms;
56 	u_int32_t	a_entry;
57 	u_int32_t	a_trsize;
58 	u_int32_t	a_drsize;
59 };
60 #define A_MAGIC 0x01030107
61 
62 static void usage(void);
63 
64 /*
65  * elf to a.out converter for freebsd/sparc64 bootblocks.
66  */
67 int
main(int ac,char ** av)68 main(int ac, char **av)
69 {
70 	Elf64_Half phentsize;
71 	Elf64_Half machine;
72 	Elf64_Half phnum;
73 	Elf64_Xword filesz;
74 	Elf64_Xword memsz;
75 	Elf64_Addr entry;
76 	Elf64_Off offset;
77 	Elf64_Off phoff;
78 	Elf64_Word type;
79 	unsigned char data;
80 	struct stat sb;
81 	struct exec a;
82 	Elf64_Phdr *p;
83 	Elf64_Ehdr *e;
84 	void *v;
85 	int efd;
86 	int fd;
87 	int c;
88 	int i;
89 
90 	fd = STDIN_FILENO;
91 	while ((c = getopt(ac, av, "o:")) != -1)
92 		switch (c) {
93 		case 'o':
94 			if ((fd = open(optarg, O_CREAT|O_RDWR, 0644)) < 0)
95 				err(1, "%s", optarg);
96 			break;
97 		case '?':
98 		default:
99 			usage();
100 		}
101 	ac -= optind;
102 	av += optind;
103 	if (ac == 0)
104 		usage();
105 
106 	if ((efd = open(*av, O_RDONLY)) < 0 || fstat(efd, &sb) < 0)
107 		err(1, NULL);
108 	v = mmap(NULL, sb.st_size, PROT_READ, MAP_SHARED, efd, 0);
109 	if ((e = v) == MAP_FAILED)
110 		err(1, NULL);
111 
112 	if (!IS_ELF(*e))
113 		errx(1, "not an elf file");
114 	if (e->e_ident[EI_CLASS] != ELFCLASS64)
115 		errx(1, "wrong class");
116 	data = e->e_ident[EI_DATA];
117 	if (data != ELFDATA2MSB && data != ELFDATA2LSB)
118 		errx(1, "wrong data format");
119 	if (e->e_ident[EI_VERSION] != EV_CURRENT)
120 		errx(1, "wrong elf version");
121 	machine = xe16toh(e->e_machine);
122 	if (machine != EM_SPARCV9 && machine != EM_ALPHA)
123 		errx(1, "wrong machine type");
124 	phentsize = xe16toh(e->e_phentsize);
125 	if (phentsize != sizeof(*p))
126 		errx(1, "phdr size mismatch");
127 
128 	entry = xe64toh(e->e_entry);
129 	phoff = xe64toh(e->e_phoff);
130 	phnum = xe16toh(e->e_phnum);
131 	p = (Elf64_Phdr *)((char *)e + phoff);
132 	bzero(&a, sizeof(a));
133 	for (i = 0; i < phnum; i++) {
134 		type = xe32toh(p[i].p_type);
135 		switch (type) {
136 		case PT_LOAD:
137 			if (a.a_magic != 0)
138 				errx(1, "too many loadable segments");
139 			filesz = xe64toh(p[i].p_filesz);
140 			memsz = xe64toh(p[i].p_memsz);
141 			offset = xe64toh(p[i].p_offset);
142 			a.a_magic = htoxe32(A_MAGIC);
143 			a.a_text = htoxe32(filesz);
144 			a.a_bss = htoxe32(memsz - filesz);
145 			a.a_entry = htoxe32(entry);
146 			if (write(fd, &a, sizeof(a)) != sizeof(a) ||
147 			    write(fd, (char *)e + offset, filesz) != (ssize_t)filesz)
148 				err(1, NULL);
149 			break;
150 		default:
151 			break;
152 		}
153 	}
154 
155 	return (0);
156 }
157 
158 static void
usage(void)159 usage(void)
160 {
161 
162 	fprintf(stderr, "usage: elf2aout [-o outfile] infile\n");
163 	exit(1);
164 }
165