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d427b66a JB |
1 | /* Unexec for Xenix. |
2 | Note that the GNU project considers support for Xenix operation | |
3 | a peripheral activity which should not be allowed to divert effort | |
4 | from development of the GNU system. Changes in this code will be | |
5 | installed when Xenix users send them in, but aside from that | |
6 | we don't plan to think about it, or about whether other Emacs | |
7 | maintenance might break it. | |
8 | ||
20c92ac7 | 9 | Copyright (C) 1988, 1994 Free Software Foundation, Inc. |
d427b66a JB |
10 | |
11 | This file is part of GNU Emacs. | |
12 | ||
13 | GNU Emacs is free software; you can redistribute it and/or modify | |
14 | it under the terms of the GNU General Public License as published by | |
20c92ac7 | 15 | the Free Software Foundation; either version 2, or (at your option) |
d427b66a JB |
16 | any later version. |
17 | ||
18 | GNU Emacs is distributed in the hope that it will be useful, | |
19 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
20 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
21 | GNU General Public License for more details. | |
22 | ||
23 | You should have received a copy of the GNU General Public License | |
24 | along with GNU Emacs; see the file COPYING. If not, write to | |
3b7ad313 EN |
25 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
26 | Boston, MA 02111-1307, USA. */ | |
d427b66a JB |
27 | |
28 | \f | |
29 | ||
30 | /* | |
31 | On 80386 Xenix, segmentation screws prevent us from modifying the text | |
32 | segment at all. We basically just plug a new value for "data segment | |
33 | size" into the countless headers and copy the other records straight | |
34 | through. The data segment is ORG'ed at the xs_rbase value of the data | |
35 | segment's xseg record (always @ 0x1880000, thanks to the "sophisticated | |
36 | memory management hardware" of the chip) and extends to sbrk(0), exactly. | |
37 | This code is afraid to malloc (should it be?), and alloca has to be the | |
38 | wimpy, malloc-based version; consequently, data is usually copied in | |
39 | smallish chunks. | |
40 | ||
41 | gb@entity.com | |
42 | */ | |
43 | ||
18160b98 | 44 | #include <config.h> |
d427b66a JB |
45 | #include <sys/types.h> |
46 | #include <fcntl.h> | |
47 | #include <sys/file.h> | |
48 | #include <sys/stat.h> | |
49 | #include <stdio.h> | |
50 | #include <varargs.h> | |
51 | #include <a.out.h> | |
52 | ||
53 | static void fatal_unexec (); | |
54 | ||
55 | #define READ(_fd, _buffer, _size, _error_message, _error_arg) \ | |
56 | errno = EEOF; \ | |
57 | if (read(_fd, _buffer, _size) != _size) \ | |
58 | fatal_unexec(_error_message, _error_arg); | |
59 | ||
60 | #define WRITE(_fd, _buffer, _size, _error_message, _error_arg) \ | |
61 | if (write(_fd, _buffer, _size) != _size) \ | |
62 | fatal_unexec(_error_message, _error_arg); | |
63 | ||
64 | #define SEEK(_fd, _position, _error_message, _error_arg) \ | |
65 | errno = EEOF; \ | |
66 | if (lseek(_fd, _position, L_SET) != _position) \ | |
67 | fatal_unexec(_error_message, _error_arg); | |
68 | ||
69 | extern int errno; | |
20c92ac7 | 70 | extern char *strerror (); |
d427b66a JB |
71 | #define EEOF -1 |
72 | ||
73 | #ifndef L_SET | |
74 | #define L_SET 0 | |
75 | #endif | |
76 | \f | |
77 | /* Should check the magic number of the old executable; | |
78 | not yet written. */ | |
79 | check_exec (x) | |
80 | struct xexec *x; | |
81 | { | |
82 | } | |
83 | ||
84 | ||
85 | unexec (new_name, a_name, data_start, bss_start, entry_address) | |
86 | char *new_name, *a_name; | |
87 | unsigned data_start, bss_start, entry_address; | |
88 | { | |
89 | char *sbrk (), *datalim = sbrk (0), *data_org; | |
90 | long segpos, textseen, textpos, textlen, datapos, datadiff, datalen; | |
91 | ||
92 | struct xexec u_xexec, /* a.out header */ | |
93 | *u_xexecp = &u_xexec; | |
94 | struct xext u_xext, /* extended header */ | |
95 | *u_xextp = &u_xext; | |
96 | struct xseg u_xseg, /* segment table entry */ | |
97 | *u_xsegp = &u_xseg; | |
98 | int i, nsegs, isdata = 0, infd, outfd; | |
99 | ||
100 | infd = open (a_name, O_RDONLY, 0); | |
101 | if (infd < 0) fatal_unexec ("opening %s", a_name); | |
102 | ||
103 | outfd = creat (new_name, 0666); | |
104 | if (outfd < 0) fatal_unexec ("creating %s", new_name); | |
105 | ||
106 | READ (infd, u_xexecp, sizeof (struct xexec), | |
107 | "error reading %s", a_name); | |
108 | check_exec (u_xexecp); | |
109 | READ (infd, u_xextp, sizeof (struct xext), | |
110 | "error reading %s", a_name); | |
111 | segpos = u_xextp->xe_segpos; | |
112 | nsegs = u_xextp->xe_segsize / sizeof (struct xseg); | |
113 | SEEK (infd, segpos, "seek error on %s", a_name); | |
114 | for (i = 0; i < nsegs; i ++) | |
115 | { | |
116 | READ (infd, u_xsegp, sizeof (struct xseg), | |
117 | "error reading %s", a_name); | |
118 | switch (u_xsegp->xs_type) | |
119 | { | |
120 | case XS_TTEXT: | |
121 | { | |
122 | if (i == 0) | |
123 | { | |
124 | textpos = u_xsegp->xs_filpos; | |
125 | textlen = u_xsegp->xs_psize; | |
126 | break; | |
127 | } | |
128 | fatal_unexec ("invalid text segment in %s", a_name); | |
129 | } | |
130 | case XS_TDATA: | |
131 | { | |
132 | if (i == 1) | |
133 | { | |
134 | datapos = u_xsegp->xs_filpos; | |
135 | datalen = datalim - (data_org = (char *)(u_xsegp->xs_rbase)); | |
136 | datadiff = datalen - u_xsegp->xs_psize; | |
137 | break; | |
138 | } | |
139 | fatal_unexec ("invalid data segment in %s", a_name); | |
140 | } | |
141 | default: | |
142 | { | |
143 | if (i > 1) break; | |
144 | fatal_unexec ("invalid segment record in %s", a_name); | |
145 | } | |
146 | } | |
147 | } | |
148 | u_xexecp->x_data = datalen; | |
149 | u_xexecp->x_bss = 0; | |
150 | WRITE (outfd, u_xexecp, sizeof (struct xexec), | |
151 | "error writing %s", new_name); | |
152 | WRITE (outfd, u_xextp, sizeof (struct xext), | |
153 | "error writing %s", new_name); | |
154 | SEEK (infd, segpos, "seek error on %s", a_name); | |
155 | SEEK (outfd, segpos, "seek error on %s", new_name); | |
156 | ||
157 | /* Copy the text segment record verbatim. */ | |
158 | ||
159 | copyrec (infd, outfd, sizeof (struct xseg), a_name, new_name); | |
160 | ||
161 | /* Read, modify, write the data segment record. */ | |
162 | ||
163 | READ (infd, u_xsegp, sizeof (struct xseg), | |
164 | "error reading %s", a_name); | |
165 | u_xsegp->xs_psize = u_xsegp->xs_vsize = datalen; | |
166 | u_xsegp->xs_attr &= (~XS_AITER & ~XS_ABSS); | |
167 | WRITE (outfd, u_xsegp, sizeof (struct xseg), | |
168 | "error writing %s", new_name); | |
169 | ||
170 | /* Now copy any additional segment records, adjusting their | |
171 | file position field */ | |
172 | ||
173 | for (i = 2; i < nsegs; i++) | |
174 | { | |
175 | READ (infd, u_xsegp, sizeof (struct xseg), | |
176 | "error reading %s", a_name); | |
177 | u_xsegp->xs_filpos += datadiff; | |
178 | WRITE (outfd, u_xsegp, sizeof (struct xseg), | |
179 | "error writing %s", new_name); | |
180 | } | |
181 | ||
182 | SEEK (infd, textpos, "seek error on %s", a_name); | |
183 | SEEK (outfd, textpos, "seek error on %s", new_name); | |
184 | copyrec (infd, outfd, textlen, a_name, new_name); | |
185 | ||
186 | SEEK (outfd, datapos, "seek error on %s", new_name); | |
187 | WRITE (outfd, data_org, datalen, | |
188 | "write error on %s", new_name); | |
189 | ||
190 | for (i = 2, segpos += (2 * sizeof (struct xseg)); | |
191 | i < nsegs; | |
192 | i++, segpos += sizeof (struct xseg)) | |
193 | { | |
194 | SEEK (infd, segpos, "seek error on %s", a_name); | |
195 | READ (infd, u_xsegp, sizeof (struct xseg), | |
196 | "read error on %s", a_name); | |
197 | SEEK (infd, u_xsegp->xs_filpos, "seek error on %s", a_name); | |
198 | /* We should be at eof in the output file here, but we must seek | |
199 | because the xs_filpos and xs_psize fields in symbol table | |
200 | segments are inconsistent. */ | |
201 | SEEK (outfd, u_xsegp->xs_filpos + datadiff, "seek error on %s", new_name); | |
202 | copyrec (infd, outfd, u_xsegp->xs_psize, a_name, new_name); | |
203 | } | |
204 | close (infd); | |
205 | close (outfd); | |
206 | mark_x (new_name); | |
207 | return 0; | |
208 | } | |
209 | ||
210 | copyrec (infd, outfd, len, in_name, out_name) | |
211 | int infd, outfd, len; | |
212 | char *in_name, *out_name; | |
213 | { | |
214 | char buf[BUFSIZ]; | |
215 | int chunk; | |
216 | ||
217 | while (len) | |
218 | { | |
219 | chunk = BUFSIZ; | |
220 | if (chunk > len) | |
221 | chunk = len; | |
222 | READ (infd, buf, chunk, "error reading %s", in_name); | |
223 | WRITE (outfd, buf, chunk, "error writing %s", out_name); | |
224 | len -= chunk; | |
225 | } | |
226 | } | |
227 | ||
228 | /* | |
229 | * mark_x | |
230 | * | |
eb8c3be9 | 231 | * After successfully building the new a.out, mark it executable |
d427b66a JB |
232 | */ |
233 | static | |
234 | mark_x (name) | |
235 | char *name; | |
236 | { | |
237 | struct stat sbuf; | |
238 | int um = umask (777); | |
239 | umask (um); | |
240 | if (stat (name, &sbuf) < 0) | |
241 | fatal_unexec ("getting protection on %s", name); | |
242 | sbuf.st_mode |= 0111 & ~um; | |
243 | if (chmod (name, sbuf.st_mode) < 0) | |
244 | fatal_unexec ("setting protection on %s", name); | |
245 | } | |
246 | ||
247 | static void | |
248 | fatal_unexec (s, va_alist) | |
249 | va_dcl | |
250 | { | |
251 | va_list ap; | |
252 | if (errno == EEOF) | |
253 | fputs ("unexec: unexpected end of file, ", stderr); | |
d427b66a | 254 | else |
20c92ac7 | 255 | fprintf (stderr, "unexec: %s, ", strerror (errno)); |
d427b66a JB |
256 | va_start (ap); |
257 | _doprnt (s, ap, stderr); | |
258 | fputs (".\n", stderr); | |
259 | exit (1); | |
260 | } |