xref: /freebsd/contrib/elftoolchain/libpe/libpe_init.c (revision f7c32ed617858bcd22f8d1b03199099d50125721)
1 /*-
2  * Copyright (c) 2015 Kai Wang
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/stat.h>
28 #include <assert.h>
29 #include <errno.h>
30 #include <stdlib.h>
31 #include <unistd.h>
32 
33 #include "_libpe.h"
34 
35 ELFTC_VCSID("$Id: libpe_init.c 3312 2016-01-10 09:23:51Z kaiwang27 $");
36 
37 int
38 libpe_open_object(PE *pe)
39 {
40 	struct stat sb;
41 	mode_t mode;
42 	char magic[sizeof(PE_DosHdr)];
43 
44 	if (fstat(pe->pe_fd, &sb) < 0)
45 		return (-1);
46 
47 	mode = sb.st_mode;
48 	pe->pe_fsize = (size_t) sb.st_size;
49 
50 	/* Reject unsupported file types. */
51 	if (!S_ISREG(mode) && !S_ISCHR(mode) && !S_ISFIFO(mode) &&
52 	    !S_ISSOCK(mode)) {
53 		errno = EINVAL;
54 		return (-1);
55 	}
56 
57 	/* Read/Write mode is not supported for non-regular file. */
58 	if (pe->pe_cmd == PE_C_RDWR && !S_ISREG(mode)) {
59 		errno = EINVAL;
60 		return (-1);
61 	}
62 
63 	/* The minimal file should at least contain a COFF header. */
64 	if (S_ISREG(mode) && pe->pe_fsize < sizeof(PE_CoffHdr)) {
65 		errno = ENOENT;
66 		return (-1);
67 	}
68 
69 	/*
70 	 * Search for MS-DOS header or COFF header.
71 	 */
72 
73 	if (read(pe->pe_fd, magic, 2) != 2) {
74 		errno = EIO;
75 		return (-1);
76 	}
77 
78 	if (magic[0] == 'M' && magic[1] == 'Z') {
79 		pe->pe_obj = PE_O_PE32;
80 		if (read(pe->pe_fd, &magic[2], sizeof(PE_DosHdr) - 2) !=
81 		    (ssize_t) sizeof(PE_DosHdr) - 2) {
82 			errno = EIO;
83 			return (-1);
84 		}
85 		return (libpe_parse_msdos_header(pe, magic));
86 
87 	} else if (magic[0] == 'P' && magic[1] == 'E') {
88 		if (read(pe->pe_fd, magic, 2) != 2) {
89 			errno = EIO;
90 			return (-1);
91 		}
92 		if (magic[0] == '\0' && magic[1] == '\0') {
93 			pe->pe_obj = PE_O_PE32;
94 			if (read(pe->pe_fd, magic, sizeof(PE_CoffHdr)) !=
95 			    (ssize_t) sizeof(PE_CoffHdr)) {
96 				errno = EIO;
97 				return (-1);
98 			}
99 			return (libpe_parse_coff_header(pe, magic));
100 		}
101 		errno = ENOENT;
102 		return (-1);
103 
104 	} else {
105 		pe->pe_obj = PE_O_COFF;
106 		if (read(pe->pe_fd, &magic[2], sizeof(PE_CoffHdr) - 2) !=
107 		    (ssize_t) sizeof(PE_CoffHdr) - 2) {
108 			errno = EIO;
109 			return (-1);
110 		}
111 		return (libpe_parse_coff_header(pe, magic));
112 	}
113 }
114 
115 void
116 libpe_release_object(PE *pe)
117 {
118 	PE_Scn *ps, *_ps;
119 
120 	if (pe->pe_dh)
121 		free(pe->pe_dh);
122 
123 	if (pe->pe_rh) {
124 		free(pe->pe_rh->rh_compid);
125 		free(pe->pe_rh->rh_cnt);
126 		free(pe->pe_rh);
127 	}
128 
129 	if (pe->pe_ch)
130 		free(pe->pe_ch);
131 
132 	if (pe->pe_oh)
133 		free(pe->pe_oh);
134 
135 	if (pe->pe_dd)
136 		free(pe->pe_dd);
137 
138 	if (pe->pe_stub)
139 		free(pe->pe_stub);
140 
141 	STAILQ_FOREACH_SAFE(ps, &pe->pe_scn, ps_next, _ps)
142 		libpe_release_scn(ps);
143 
144 	free(pe);
145 }
146