1/*
2 * ----------------------------------------------------------------------------
3 * "THE BEER-WARE LICENSE" (Revision 42):
4 * <phk@login.dkuug.dk> wrote this file. As long as you retain this notice you
5 * can do whatever you want with this stuff. If we meet some day, and you think
6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
7 * ----------------------------------------------------------------------------
8 *
9 * $Id: imgact_gzip.c,v 1.20 1996/03/19 15:02:47 bde Exp $
10 *
11 * This module handles execution of a.out files which have been run through
12 * "gzip". This saves diskspace, but wastes cpu-cycles and VM.
13 *
14 * TODO:
15 * text-segments should be made R/O after being filled
16 * is the vm-stuff safe ?
17 * should handle the entire header of gzip'ed stuff.
18 * inflate isn't quite reentrant yet...
19 * error-handling is a mess...
20 * so is the rest...
21 * tidy up unnecesary includes
22 */
23
24#include <sys/param.h>
25#include <sys/exec.h>
26#include <sys/imgact.h>
27#include <sys/imgact_aout.h>
28#include <sys/kernel.h>
29#include <sys/mman.h>
30#include <sys/proc.h>
31#include <sys/resourcevar.h>
32#include <sys/sysent.h>
33#include <sys/systm.h>
34#include <sys/vnode.h>
35#include <sys/inflate.h>
36
37#include <vm/vm.h>
38#include <vm/vm_param.h>
39#include <vm/vm_prot.h>
40#include <vm/lock.h>
41#include <vm/pmap.h>
42#include <vm/vm_map.h>
43#include <vm/vm_kern.h>
44#include <vm/vm_extern.h>
45
46struct imgact_gzip {
47 struct image_params *ip;
48 struct exec a_out;
49 int error;
50 int where;
51 u_char *inbuf;
52 u_long offset;
53 u_long output;
54 u_long len;
55 int idx;
56 u_long virtual_offset, file_offset, file_end, bss_size;
57};
58
59static int exec_gzip_imgact __P((struct image_params *imgp));
60static int NextByte __P((void *vp));
61static int do_aout_hdr __P((struct imgact_gzip *));
62static int Flush __P((void *vp, u_char *, u_long siz));
63
64static int
65exec_gzip_imgact(imgp)
66 struct image_params *imgp;
67{
68 int error, error2 = 0;
69 u_char *p = (u_char *) imgp->image_header;
70 struct imgact_gzip igz;
71 struct inflate infl;
72
73 /* If these four are not OK, it isn't a gzip file */
74 if (p[0] != 0x1f)
75 return -1; /* 0 Simply magic */
76 if (p[1] != 0x8b)
77 return -1; /* 1 Simply magic */
78 if (p[2] != 0x08)
79 return -1; /* 2 Compression method */
80 if (p[9] != 0x03)
81 return -1; /* 9 OS compressed on */
82
83 /*
84 * If this one contains anything but a comment or a filename marker,
85 * we don't want to chew on it
86 */
87 if (p[3] & ~(0x18))
88 return ENOEXEC; /* 3 Flags */
89
90 /* These are of no use to us */
91 /* 4-7 Timestamp */
92 /* 8 Extra flags */
93
94 bzero(&igz, sizeof igz);
95 bzero(&infl, sizeof infl);
96 infl.gz_private = (void *) &igz;
97 infl.gz_input = NextByte;
98 infl.gz_output = Flush;
99
100 igz.ip = imgp;
101 igz.idx = 10;
102
103 if (p[3] & 0x08) { /* skip a filename */
104 while (p[igz.idx++])
105 if (igz.idx >= PAGE_SIZE)
106 return ENOEXEC;
107 }
108 if (p[3] & 0x10) { /* skip a comment */
109 while (p[igz.idx++])
110 if (igz.idx >= PAGE_SIZE)
111 return ENOEXEC;
112 }
113 igz.len = igz.ip->attr->va_size;
114
115 error = inflate(&infl);
116
117 if (igz.inbuf) {
118 error2 =
119 vm_map_remove(kernel_map, (vm_offset_t) igz.inbuf,
120 (vm_offset_t) igz.inbuf + PAGE_SIZE);
121 }
122 if (igz.error || error || error2) {
123 printf("Output=%lu ", igz.output);
124 printf("Inflate_error=%d igz.error=%d error2=%d where=%d\n",
125 error, igz.error, error2, igz.where);
126 }
127 if (igz.error)
128 return igz.error;
129 if (error)
130 return ENOEXEC;
131 if (error2)
132 return error2;
133 return 0;
134}
135
136static int
137do_aout_hdr(struct imgact_gzip * gz)
138{
139 int error;
140 struct vmspace *vmspace = gz->ip->proc->p_vmspace;
141 vm_offset_t vmaddr;
142
143 /*
144 * Set file/virtual offset based on a.out variant. We do two cases:
145 * host byte order and network byte order (for NetBSD compatibility)
146 */
147 switch ((int) (gz->a_out.a_magic & 0xffff)) {
148 case ZMAGIC:
149 gz->virtual_offset = 0;
150 if (gz->a_out.a_text) {
151 gz->file_offset = NBPG;
152 } else {
153 /* Bill's "screwball mode" */
154 gz->file_offset = 0;
155 }
156 break;
157 case QMAGIC:
158 gz->virtual_offset = NBPG;
159 gz->file_offset = 0;
160 break;
161 default:
162 /* NetBSD compatibility */
163 switch ((int) (ntohl(gz->a_out.a_magic) & 0xffff)) {
164 case ZMAGIC:
165 case QMAGIC:
166 gz->virtual_offset = NBPG;
167 gz->file_offset = 0;
168 break;
169 default:
170 gz->where = __LINE__;
171 return (-1);
172 }
173 }
174
175 gz->bss_size = roundup(gz->a_out.a_bss, NBPG);
176
177 /*
178 * Check various fields in header for validity/bounds.
179 */
180 if ( /* entry point must lay with text region */
181 gz->a_out.a_entry < gz->virtual_offset ||
182 gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
183
184 /* text and data size must each be page rounded */
185 gz->a_out.a_text % NBPG ||
186 gz->a_out.a_data % NBPG) {
187 gz->where = __LINE__;
188 return (-1);
189 }
190 /*
191 * text/data/bss must not exceed limits
192 */
193 if ( /* text can't exceed maximum text size */
194 gz->a_out.a_text > MAXTSIZ ||
195
196 /* data + bss can't exceed maximum data size */
197 gz->a_out.a_data + gz->bss_size > MAXDSIZ ||
198
199 /* data + bss can't exceed rlimit */
200 gz->a_out.a_data + gz->bss_size >
201 gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
202 gz->where = __LINE__;
203 return (ENOMEM);
204 }
205 /* Find out how far we should go */
206 gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
207
208 /* copy in arguments and/or environment from old process */
209 error = exec_extract_strings(gz->ip);
210 if (error) {
211 gz->where = __LINE__;
212 return (error);
213 }
214 /*
215 * Destroy old process VM and create a new one (with a new stack)
216 */
217 exec_new_vmspace(gz->ip);
218
219 vmaddr = gz->virtual_offset;
220
221 error = vm_mmap(&vmspace->vm_map, /* map */
222 &vmaddr,/* address */
223 gz->a_out.a_text, /* size */
224 VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_WRITE, /* protection */
225 VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_WRITE,
226 MAP_ANON | MAP_FIXED, /* flags */
227 0, /* vnode */
228 0); /* offset */
229
230 if (error) {
231 gz->where = __LINE__;
232 return (error);
233 }
234 vmaddr = gz->virtual_offset + gz->a_out.a_text;
235
236 /*
237 * Map data read/write (if text is 0, assume text is in data area
238 * [Bill's screwball mode])
239 */
240
241 error = vm_mmap(&vmspace->vm_map,
242 &vmaddr,
243 gz->a_out.a_data,
244 VM_PROT_READ | VM_PROT_WRITE | (gz->a_out.a_text ? 0 : VM_PROT_EXECUTE),
245 VM_PROT_ALL, MAP_ANON | MAP_FIXED,
246 0,
247 0);
248
249 if (error) {
250 gz->where = __LINE__;
251 return (error);
252 }
253 if (gz->bss_size != 0) {
254 /*
255 * Allocate demand-zeroed area for uninitialized data.
256 * "bss" = 'block started by symbol' - named after the
257 * IBM 7090 instruction of the same name.
258 */
259 vmaddr = gz->virtual_offset + gz->a_out.a_text +
260 gz->a_out.a_data;
261 error = vm_map_find(&vmspace->vm_map, NULL, 0, &vmaddr,
262 gz->bss_size, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
263 if (error) {
264 gz->where = __LINE__;
265 return (error);
266 }
267 }
268 /* Fill in process VM information */
269 vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
270 vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
271 vmspace->vm_taddr = (caddr_t) gz->virtual_offset;
272 vmspace->vm_daddr = (caddr_t) gz->virtual_offset + gz->a_out.a_text;
273
274 /* Fill in image_params */
275 gz->ip->interpreted = 0;
276 gz->ip->entry_addr = gz->a_out.a_entry;
277
278 gz->ip->proc->p_sysent = &aout_sysvec;
279
280 return 0;
281}
282
283static int
284NextByte(void *vp)
285{
286 int error;
287 struct imgact_gzip *igz = (struct imgact_gzip *) vp;
288
289 if (igz->idx >= igz->len) {
290 igz->where = __LINE__;
291 return GZ_EOF;
292 }
293 if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
294 return igz->inbuf[(igz->idx++) - igz->offset];
295 }
296 if (igz->inbuf) {
297 error = vm_map_remove(kernel_map, (vm_offset_t) igz->inbuf,
298 (vm_offset_t) igz->inbuf + PAGE_SIZE);
299 if (error) {
300 igz->where = __LINE__;
301 igz->error = error;
302 return GZ_EOF;
303 }
304 }
305 igz->offset = igz->idx & ~PAGE_MASK;
306
307 error = vm_mmap(kernel_map, /* map */
308 (vm_offset_t *) & igz->inbuf, /* address */
309 PAGE_SIZE, /* size */
310 VM_PROT_READ, /* protection */
311 VM_PROT_READ, /* max protection */
312 0, /* flags */
313 (caddr_t) igz->ip->vp, /* vnode */
314 igz->offset); /* offset */
315 if (error) {
316 igz->where = __LINE__;
317 igz->error = error;
318 return GZ_EOF;
319 }
320 return igz->inbuf[(igz->idx++) - igz->offset];
321}
322
323static int
324Flush(void *vp, u_char * ptr, u_long siz)
325{
326 struct imgact_gzip *gz = (struct imgact_gzip *) vp;
327 u_char *p = ptr, *q;
328 int i;
329
330 /* First, find a a.out-header */
331 if (gz->output < sizeof gz->a_out) {
332 q = (u_char *) & gz->a_out;
333 i = min(siz, sizeof gz->a_out - gz->output);
334 bcopy(p, q + gz->output, i);
335 gz->output += i;
336 p += i;
337 siz -= i;
338 if (gz->output == sizeof gz->a_out) {
339 i = do_aout_hdr(gz);
340 if (i == -1) {
341 if (!gz->where)
342 gz->where = __LINE__;
343 gz->error = ENOEXEC;
344 return ENOEXEC;
345 } else if (i) {
346 gz->where = __LINE__;
347 gz->error = i;
348 return ENOEXEC;
349 }
350 if (gz->file_offset < sizeof gz->a_out) {
351 q = (u_char *) gz->virtual_offset + gz->output - gz->file_offset;
352 bcopy(&gz->a_out, q, sizeof gz->a_out - gz->file_offset);
353 }
354 }
355 }
356 /* Skip over zero-padded first PAGE if needed */
357 if (gz->output < gz->file_offset && (gz->output + siz) > gz->file_offset) {
358 i = min(siz, gz->file_offset - gz->output);
359 gz->output += i;
360 p += i;
361 siz -= i;
362 }
363 if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
364 i = min(siz, gz->file_end - gz->output);
365 q = (u_char *) gz->virtual_offset + gz->output - gz->file_offset;
366 bcopy(p, q, i);
367 gz->output += i;
368 p += i;
369 siz -= i;
370 }
371 gz->output += siz;
372 return 0;
373}
374
375
376/*
377 * Tell kern_execve.c about it, with a little help from the linker.
378 * Since `const' objects end up in the text segment, TEXT_SET is the
379 * correct directive to use.
380 */
381
382static const struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
383TEXT_SET(execsw_set, gzip_execsw);