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 1.33 1998/06/16 14:36:40 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 <sys/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 const u_char *p = (const u_char *) imgp->image_header;
70 struct imgact_gzip igz;
71 struct inflate infl;
72 struct vmspace *vmspace;
73
74 /* If these four are not OK, it isn't a gzip file */
75 if (p[0] != 0x1f)
76 return -1; /* 0 Simply magic */
77 if (p[1] != 0x8b)
78 return -1; /* 1 Simply magic */
79 if (p[2] != 0x08)
80 return -1; /* 2 Compression method */
81 if (p[9] != 0x03)
82 return -1; /* 9 OS compressed on */
83
84 /*
85 * If this one contains anything but a comment or a filename marker,
86 * we don't want to chew on it
87 */
88 if (p[3] & ~(0x18))
89 return ENOEXEC; /* 3 Flags */
90
91 /* These are of no use to us */
92 /* 4-7 Timestamp */
93 /* 8 Extra flags */
94
95 bzero(&igz, sizeof igz);
96 bzero(&infl, sizeof infl);
97 infl.gz_private = (void *) &igz;
98 infl.gz_input = NextByte;
99 infl.gz_output = Flush;
100
101 igz.ip = imgp;
102 igz.idx = 10;
103
104 if (p[3] & 0x08) { /* skip a filename */
105 while (p[igz.idx++])
106 if (igz.idx >= PAGE_SIZE)
107 return ENOEXEC;
108 }
109 if (p[3] & 0x10) { /* skip a comment */
110 while (p[igz.idx++])
111 if (igz.idx >= PAGE_SIZE)
112 return ENOEXEC;
113 }
114 igz.len = imgp->attr->va_size;
115
116 error = inflate(&infl);
117
118 if ( !error ) {
119 vmspace = imgp->proc->p_vmspace;
120 error = vm_map_protect(&vmspace->vm_map,
121 (vm_offset_t) vmspace->vm_taddr,
122 (vm_offset_t) (vmspace->vm_taddr +
123 (vmspace->vm_tsize << PAGE_SHIFT)) ,
124 VM_PROT_READ|VM_PROT_EXECUTE,0);
125 }
126
127 if (igz.inbuf) {
128 error2 =
129 vm_map_remove(kernel_map, (vm_offset_t) igz.inbuf,
130 (vm_offset_t) igz.inbuf + PAGE_SIZE);
131 }
132 if (igz.error || error || error2) {
133 printf("Output=%lu ", igz.output);
134 printf("Inflate_error=%d igz.error=%d error2=%d where=%d\n",
135 error, igz.error, error2, igz.where);
136 }
137 if (igz.error)
138 return igz.error;
139 if (error)
140 return ENOEXEC;
141 if (error2)
142 return error2;
143 return 0;
144}
145
146static int
147do_aout_hdr(struct imgact_gzip * gz)
148{
149 int error;
150 struct vmspace *vmspace;
151 vm_offset_t vmaddr;
152
153 /*
154 * Set file/virtual offset based on a.out variant. We do two cases:
155 * host byte order and network byte order (for NetBSD compatibility)
156 */
157 switch ((int) (gz->a_out.a_magic & 0xffff)) {
158 case ZMAGIC:
159 gz->virtual_offset = 0;
160 if (gz->a_out.a_text) {
161 gz->file_offset = PAGE_SIZE;
162 } else {
163 /* Bill's "screwball mode" */
164 gz->file_offset = 0;
165 }
166 break;
167 case QMAGIC:
168 gz->virtual_offset = PAGE_SIZE;
169 gz->file_offset = 0;
170 break;
171 default:
172 /* NetBSD compatibility */
173 switch ((int) (ntohl(gz->a_out.a_magic) & 0xffff)) {
174 case ZMAGIC:
175 case QMAGIC:
176 gz->virtual_offset = PAGE_SIZE;
177 gz->file_offset = 0;
178 break;
179 default:
180 gz->where = __LINE__;
181 return (-1);
182 }
183 }
184
185 gz->bss_size = roundup(gz->a_out.a_bss, PAGE_SIZE);
186
187 /*
188 * Check various fields in header for validity/bounds.
189 */
190 if ( /* entry point must lay with text region */
191 gz->a_out.a_entry < gz->virtual_offset ||
192 gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
193
194 /* text and data size must each be page rounded */
195 gz->a_out.a_text & PAGE_MASK || gz->a_out.a_data & PAGE_MASK) {
196 gz->where = __LINE__;
197 return (-1);
198 }
199 /*
200 * text/data/bss must not exceed limits
201 */
202 if ( /* text can't exceed maximum text size */
203 gz->a_out.a_text > MAXTSIZ ||
204
205 /* data + bss can't exceed rlimit */
206 gz->a_out.a_data + gz->bss_size >
207 gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
208 gz->where = __LINE__;
209 return (ENOMEM);
210 }
211 /* Find out how far we should go */
212 gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
213
214 /* copy in arguments and/or environment from old process */
215 error = exec_extract_strings(gz->ip);
216 if (error) {
217 gz->where = __LINE__;
218 return (error);
219 }
220 /*
221 * Destroy old process VM and create a new one (with a new stack)
222 */
223 exec_new_vmspace(gz->ip);
224
225 vmspace = gz->ip->proc->p_vmspace;
226
227 vmaddr = gz->virtual_offset;
228
229 error = vm_mmap(&vmspace->vm_map,
230 &vmaddr,
231 gz->a_out.a_text + gz->a_out.a_data,
232 VM_PROT_ALL, VM_PROT_ALL, MAP_ANON | MAP_FIXED,
233 0,
234 0);
235
236 if (error) {
237 gz->where = __LINE__;
238 return (error);
239 }
240
241 if (gz->bss_size != 0) {
242 /*
243 * Allocate demand-zeroed area for uninitialized data.
244 * "bss" = 'block started by symbol' - named after the
245 * IBM 7090 instruction of the same name.
246 */
247 vmaddr = gz->virtual_offset + gz->a_out.a_text +
248 gz->a_out.a_data;
249 error = vm_map_find(&vmspace->vm_map,
250 NULL,
251 0,
252 &vmaddr,
253 gz->bss_size,
254 FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
255 if (error) {
256 gz->where = __LINE__;
257 return (error);
258 }
259 }
260 /* Fill in process VM information */
261 vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
262 vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
263 vmspace->vm_taddr = (caddr_t) (uintptr_t) gz->virtual_offset;
264 vmspace->vm_daddr = (caddr_t) (uintptr_t)
265 (gz->virtual_offset + gz->a_out.a_text);
266
267 /* Fill in image_params */
268 gz->ip->interpreted = 0;
269 gz->ip->entry_addr = gz->a_out.a_entry;
270
271 gz->ip->proc->p_sysent = &aout_sysvec;
272
273 return 0;
274}
275
276static int
277NextByte(void *vp)
278{
279 int error;
280 struct imgact_gzip *igz = (struct imgact_gzip *) vp;
281
282 if (igz->idx >= igz->len) {
283 igz->where = __LINE__;
284 return GZ_EOF;
285 }
286 if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
287 return igz->inbuf[(igz->idx++) - igz->offset];
288 }
289 if (igz->inbuf) {
290 error = vm_map_remove(kernel_map, (vm_offset_t) igz->inbuf,
291 (vm_offset_t) igz->inbuf + PAGE_SIZE);
292 if (error) {
293 igz->where = __LINE__;
294 igz->error = error;
295 return GZ_EOF;
296 }
297 }
298 igz->offset = igz->idx & ~PAGE_MASK;
299
300 error = vm_mmap(kernel_map, /* map */
301 (vm_offset_t *) & igz->inbuf, /* address */
302 PAGE_SIZE, /* size */
303 VM_PROT_READ, /* protection */
304 VM_PROT_READ, /* max protection */
305 0, /* flags */
306 (caddr_t) igz->ip->vp, /* vnode */
307 igz->offset); /* offset */
308 if (error) {
309 igz->where = __LINE__;
310 igz->error = error;
311 return GZ_EOF;
312 }
313 return igz->inbuf[(igz->idx++) - igz->offset];
314}
315
316static int
317Flush(void *vp, u_char * ptr, u_long siz)
318{
319 struct imgact_gzip *gz = (struct imgact_gzip *) vp;
320 u_char *p = ptr, *q;
321 int i;
322
323 /* First, find a a.out-header */
324 if (gz->output < sizeof gz->a_out) {
325 q = (u_char *) & gz->a_out;
326 i = min(siz, sizeof gz->a_out - gz->output);
327 bcopy(p, q + gz->output, i);
328 gz->output += i;
329 p += i;
330 siz -= i;
331 if (gz->output == sizeof gz->a_out) {
332 i = do_aout_hdr(gz);
333 if (i == -1) {
334 if (!gz->where)
335 gz->where = __LINE__;
336 gz->error = ENOEXEC;
337 return ENOEXEC;
338 } else if (i) {
339 gz->where = __LINE__;
340 gz->error = i;
341 return ENOEXEC;
342 }
343 if (gz->file_offset == 0) {
344 q = (u_char *) (uintptr_t) gz->virtual_offset;
345 copyout(&gz->a_out, q, sizeof gz->a_out);
346 }
347 }
348 }
349 /* Skip over zero-padded first PAGE if needed */
350 if (gz->output < gz->file_offset &&
351 gz->output + siz > gz->file_offset) {
352 i = min(siz, gz->file_offset - gz->output);
353 gz->output += i;
354 p += i;
355 siz -= i;
356 }
357 if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
358 i = min(siz, gz->file_end - gz->output);
359 q = (u_char *) (uintptr_t)
360 (gz->virtual_offset + gz->output - gz->file_offset);
361 copyout(p, q, i);
362 gz->output += i;
363 p += i;
364 siz -= i;
365 }
366 gz->output += siz;
367 return 0;
368}
369
370
371/*
372 * Tell kern_execve.c about it, with a little help from the linker.
373 * Since `const' objects end up in the text segment, TEXT_SET is the
374 * correct directive to use.
375 */
376
377static const struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
378TEXT_SET(execsw_set, gzip_execsw);