imgact_gzip.c revision 15494 
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);
384