xref: /freebsd/usr.sbin/btxld/btxld.c (revision 911f0260390e18cf85f3dbf2c719b593efdc1e3c)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 1998 Robert Nordier
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
21  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
22  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
23  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
25  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
26  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #ifndef lint
30 static const char rcsid[] =
31   "$FreeBSD$";
32 #endif /* not lint */
33 
34 #include <sys/param.h>
35 #include <sys/endian.h>
36 #include <sys/stat.h>
37 #include <sys/mman.h>
38 
39 /* XXX make this work as an i386/amd64 cross-tool */
40 #include <machine/exec.h>
41 #undef __LDPGSZ
42 #define __LDPGSZ	4096
43 
44 #include <netinet/in.h>
45 
46 #include <a.out.h>
47 #include <err.h>
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <stdarg.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <unistd.h>
55 
56 #include "btx.h"
57 #include "elfh.h"
58 
59 #define BTX_PATH		"/sys/boot/i386/btx"
60 
61 #define I_LDR	0		/* BTX loader */
62 #define I_BTX	1		/* BTX kernel */
63 #define I_CLNT	2		/* Client program */
64 
65 #define F_BIN	0		/* Binary */
66 #define F_AOUT	1		/* ZMAGIC a.out */
67 #define F_ELF	2		/* 32-bit ELF */
68 #define F_CNT	3		/* Number of formats */
69 
70 #define IMPURE	1		/* Writable text */
71 #define MAXU32	0xffffffff	/* Maximum unsigned 32-bit quantity */
72 
73 struct hdr {
74     uint32_t fmt;		/* Format */
75     uint32_t flags;		/* Bit flags */
76     uint32_t size;		/* Size of file */
77     uint32_t text;		/* Size of text segment */
78     uint32_t data;		/* Size of data segment */
79     uint32_t bss;		/* Size of bss segment */
80     uint32_t org;		/* Program origin */
81     uint32_t entry;		/* Program entry point */
82 };
83 
84 static const char *const fmtlist[] = {"bin", "aout", "elf"};
85 
86 static const char binfo[] =
87     "kernel: ver=%u.%02u size=%x load=%x entry=%x map=%uM "
88     "pgctl=%x:%x\n";
89 static const char cinfo[] =
90     "client: fmt=%s size=%x text=%x data=%x bss=%x entry=%x\n";
91 static const char oinfo[] =
92     "output: fmt=%s size=%x text=%x data=%x org=%x entry=%x\n";
93 
94 static const char *lname =
95     BTX_PATH "/btxldr/btxldr";	/* BTX loader */
96 static const char *bname =
97     BTX_PATH "/btx/btx";	/* BTX kernel */
98 static const char *oname =
99     "a.out";			/* Output filename */
100 
101 static int ppage = -1;		/* First page present */
102 static int wpage = -1;		/* First page writable */
103 
104 static unsigned int format; 	/* Output format */
105 
106 static uint32_t centry; 	/* Client entry address */
107 static uint32_t lentry; 	/* Loader entry address */
108 
109 static int Eflag;		/* Client entry option */
110 
111 static int quiet;		/* Inhibit warnings */
112 static int verbose;		/* Display information */
113 
114 static const char *tname;	/* Temporary output file */
115 static const char *fname;	/* Current input file */
116 
117 static void cleanup(void);
118 static void btxld(const char *);
119 static void getbtx(int, struct btx_hdr *);
120 static void gethdr(int, struct hdr *);
121 static void puthdr(int, struct hdr *);
122 static void copy(int, int, size_t, off_t);
123 static size_t readx(int, void *, size_t, off_t);
124 static void writex(int, const void *, size_t);
125 static void seekx(int, off_t);
126 static unsigned int optfmt(const char *);
127 static uint32_t optaddr(const char *);
128 static int optpage(const char *, int);
129 static void Warn(const char *, const char *, ...);
130 static void usage(void);
131 
132 /*
133  * A link editor for BTX clients.
134  */
135 int
136 main(int argc, char *argv[])
137 {
138     int c;
139 
140     while ((c = getopt(argc, argv, "qvb:E:e:f:l:o:P:W:")) != -1)
141 	switch (c) {
142 	case 'q':
143 	    quiet = 1;
144 	    break;
145 	case 'v':
146 	    verbose = 1;
147 	    break;
148 	case 'b':
149 	    bname = optarg;
150 	    break;
151 	case 'E':
152 	    centry = optaddr(optarg);
153 	    Eflag = 1;
154 	    break;
155 	case 'e':
156 	    lentry = optaddr(optarg);
157 	    break;
158 	case 'f':
159 	    format = optfmt(optarg);
160 	    break;
161 	case 'l':
162 	    lname = optarg;
163 	    break;
164 	case 'o':
165 	    oname = optarg;
166 	    break;
167 	case 'P':
168 	    ppage = optpage(optarg, 1);
169 	    break;
170 	case 'W':
171 	    wpage = optpage(optarg, BTX_MAXCWR);
172 	    break;
173 	default:
174 	    usage();
175 	}
176     argc -= optind;
177     argv += optind;
178     if (argc != 1)
179 	usage();
180     atexit(cleanup);
181     btxld(*argv);
182     return 0;
183 }
184 
185 /*
186  * Clean up after errors.
187  */
188 static void
189 cleanup(void)
190 {
191     if (tname)
192 	(void)remove(tname);
193 }
194 
195 /*
196  * Read the input files; write the output file; display information.
197  */
198 static void
199 btxld(const char *iname)
200 {
201     char name[FILENAME_MAX];
202     struct btx_hdr btx, btxle;
203     struct hdr ihdr, ohdr;
204     unsigned int ldr_size, cwr;
205     int fdi[3], fdo, i;
206 
207     ldr_size = 0;
208 
209     for (i = I_LDR; i <= I_CLNT; i++) {
210 	fname = i == I_LDR ? lname : i == I_BTX ? bname : iname;
211 	if ((fdi[i] = open(fname, O_RDONLY)) == -1)
212 	    err(2, "%s", fname);
213 	switch (i) {
214 	case I_LDR:
215 	    gethdr(fdi[i], &ihdr);
216 	    if (ihdr.fmt != F_BIN)
217 		Warn(fname, "Loader format is %s; processing as %s",
218 		     fmtlist[ihdr.fmt], fmtlist[F_BIN]);
219 	    ldr_size = ihdr.size;
220 	    break;
221 	case I_BTX:
222 	    getbtx(fdi[i], &btx);
223 	    break;
224 	case I_CLNT:
225 	    gethdr(fdi[i], &ihdr);
226 	    if (ihdr.org && ihdr.org != BTX_PGSIZE)
227 		Warn(fname,
228 		     "Client origin is 0x%x; expecting 0 or 0x%x",
229 		     ihdr.org, BTX_PGSIZE);
230 	}
231     }
232     memset(&ohdr, 0, sizeof(ohdr));
233     ohdr.fmt = format;
234     ohdr.text = ldr_size;
235     ohdr.data = btx.btx_textsz + ihdr.size;
236     ohdr.org = lentry;
237     ohdr.entry = lentry;
238     cwr = 0;
239     if (wpage > 0 || (wpage == -1 && !(ihdr.flags & IMPURE))) {
240 	if (wpage > 0)
241 	    cwr = wpage;
242 	else {
243 	    cwr = howmany(ihdr.text, BTX_PGSIZE);
244 	    if (cwr > BTX_MAXCWR)
245 		cwr = BTX_MAXCWR;
246 	}
247     }
248     if (ppage > 0 || (ppage && wpage && ihdr.org >= BTX_PGSIZE)) {
249 	btx.btx_flags |= BTX_MAPONE;
250 	if (!cwr)
251 	    cwr++;
252     }
253     btx.btx_pgctl -= cwr;
254     btx.btx_entry = Eflag ? centry : ihdr.entry;
255     if ((size_t)snprintf(name, sizeof(name), "%s.tmp", oname) >= sizeof(name))
256 	errx(2, "%s: Filename too long", oname);
257     if ((fdo = open(name, O_CREAT | O_TRUNC | O_WRONLY, 0666)) == -1)
258 	err(2, "%s", name);
259     if (!(tname = strdup(name)))
260 	err(2, NULL);
261     puthdr(fdo, &ohdr);
262     for (i = I_LDR; i <= I_CLNT; i++) {
263 	fname = i == I_LDR ? lname : i == I_BTX ? bname : iname;
264 	switch (i) {
265 	case I_LDR:
266 	    copy(fdi[i], fdo, ldr_size, 0);
267 	    seekx(fdo, ohdr.size += ohdr.text);
268 	    break;
269 	case I_BTX:
270 	    btxle = btx;
271 	    btxle.btx_pgctl = htole16(btxle.btx_pgctl);
272 	    btxle.btx_textsz = htole16(btxle.btx_textsz);
273 	    btxle.btx_entry = htole32(btxle.btx_entry);
274 	    writex(fdo, &btxle, sizeof(btxle));
275 	    copy(fdi[i], fdo, btx.btx_textsz - sizeof(btx),
276 		 sizeof(btx));
277 	    break;
278 	case I_CLNT:
279 	    copy(fdi[i], fdo, ihdr.size, 0);
280 	    if (ftruncate(fdo, ohdr.size += ohdr.data))
281 		err(2, "%s", tname);
282 	}
283 	if (close(fdi[i]))
284 	    err(2, "%s", fname);
285     }
286     if (close(fdo))
287 	err(2, "%s", tname);
288     if (rename(tname, oname))
289 	err(2, "%s: Can't rename to %s", tname, oname);
290     free((void*)(intptr_t)tname);
291     tname = NULL;
292     if (verbose) {
293 	printf(binfo, btx.btx_majver, btx.btx_minver, btx.btx_textsz,
294 	       BTX_ORIGIN(btx), BTX_ENTRY(btx), BTX_MAPPED(btx) *
295 	       BTX_PGSIZE / 0x100000, !!(btx.btx_flags & BTX_MAPONE),
296 	       BTX_MAPPED(btx) - btx.btx_pgctl - BTX_PGBASE /
297 	       BTX_PGSIZE - BTX_MAPPED(btx) * 4 / BTX_PGSIZE);
298 	printf(cinfo, fmtlist[ihdr.fmt], ihdr.size, ihdr.text,
299 	       ihdr.data, ihdr.bss, ihdr.entry);
300 	printf(oinfo, fmtlist[ohdr.fmt], ohdr.size, ohdr.text,
301 	       ohdr.data, ohdr.org, ohdr.entry);
302     }
303 }
304 
305 /*
306  * Read BTX file header.
307  */
308 static void
309 getbtx(int fd, struct btx_hdr * btx)
310 {
311     if (readx(fd, btx, sizeof(*btx), 0) != sizeof(*btx) ||
312 	btx->btx_magic[0] != BTX_MAG0 ||
313 	btx->btx_magic[1] != BTX_MAG1 ||
314 	btx->btx_magic[2] != BTX_MAG2)
315 	errx(1, "%s: Not a BTX kernel", fname);
316     btx->btx_pgctl = le16toh(btx->btx_pgctl);
317     btx->btx_textsz = le16toh(btx->btx_textsz);
318     btx->btx_entry = le32toh(btx->btx_entry);
319 }
320 
321 /*
322  * Get file size and read a.out or ELF header.
323  */
324 static void
325 gethdr(int fd, struct hdr *hdr)
326 {
327     struct stat sb;
328     const struct exec *ex;
329     const Elf32_Ehdr *ee;
330     const Elf32_Phdr *ep;
331     void *p;
332     unsigned int fmt, x, n, i;
333 
334     memset(hdr, 0, sizeof(*hdr));
335     if (fstat(fd, &sb))
336 	err(2, "%s", fname);
337     if (sb.st_size > MAXU32)
338 	errx(1, "%s: Too big", fname);
339     hdr->size = sb.st_size;
340     if (!hdr->size)
341 	return;
342     if ((p = mmap(NULL, hdr->size, PROT_READ, MAP_SHARED, fd,
343 		  0)) == MAP_FAILED)
344 	err(2, "%s", fname);
345     for (fmt = F_CNT - 1; !hdr->fmt && fmt; fmt--)
346 	switch (fmt) {
347 	case F_AOUT:
348 	    ex = p;
349 	    if (hdr->size >= sizeof(struct exec) && !N_BADMAG(*ex)) {
350 		hdr->fmt = fmt;
351 		x = N_GETMAGIC(*ex);
352 		if (x == OMAGIC || x == NMAGIC) {
353 		    if (x == NMAGIC)
354 			Warn(fname, "Treating %s NMAGIC as OMAGIC",
355 			     fmtlist[fmt]);
356 		    hdr->flags |= IMPURE;
357 		}
358 		hdr->text = le32toh(ex->a_text);
359 		hdr->data = le32toh(ex->a_data);
360 		hdr->bss = le32toh(ex->a_bss);
361 		hdr->entry = le32toh(ex->a_entry);
362 		if (le32toh(ex->a_entry) >= BTX_PGSIZE)
363 		    hdr->org = BTX_PGSIZE;
364 	    }
365 	    break;
366 	case F_ELF:
367 	    ee = p;
368 	    if (hdr->size >= sizeof(Elf32_Ehdr) && IS_ELF(*ee)) {
369 		hdr->fmt = fmt;
370 		for (n = i = 0; i < le16toh(ee->e_phnum); i++) {
371 		    ep = (void *)((uint8_t *)p + le32toh(ee->e_phoff) +
372 				  le16toh(ee->e_phentsize) * i);
373 		    if (le32toh(ep->p_type) == PT_LOAD)
374 			switch (n++) {
375 			case 0:
376 			    hdr->text = le32toh(ep->p_filesz);
377 			    hdr->org = le32toh(ep->p_paddr);
378 			    if (le32toh(ep->p_flags) & PF_W)
379 				hdr->flags |= IMPURE;
380 			    break;
381 			case 1:
382 			    hdr->data = le32toh(ep->p_filesz);
383 			    hdr->bss = le32toh(ep->p_memsz) -
384 				le32toh(ep->p_filesz);
385 			    break;
386 			case 2:
387 			    Warn(fname,
388 				 "Ignoring extra %s PT_LOAD segments",
389 				 fmtlist[fmt]);
390 			}
391 		}
392 		hdr->entry = le32toh(ee->e_entry);
393 	    }
394 	}
395     if (munmap(p, hdr->size))
396 	err(2, "%s", fname);
397 }
398 
399 /*
400  * Write a.out or ELF header.
401  */
402 static void
403 puthdr(int fd, struct hdr *hdr)
404 {
405     struct exec ex;
406     struct elfh eh;
407 
408     switch (hdr->fmt) {
409     case F_AOUT:
410 	memset(&ex, 0, sizeof(ex));
411 	N_SETMAGIC(ex, ZMAGIC, MID_I386, 0);
412 	hdr->text = N_ALIGN(ex, hdr->text);
413 	ex.a_text = htole32(hdr->text);
414 	hdr->data = N_ALIGN(ex, hdr->data);
415 	ex.a_data = htole32(hdr->data);
416 	ex.a_entry = htole32(hdr->entry);
417 	writex(fd, &ex, sizeof(ex));
418 	hdr->size = N_ALIGN(ex, sizeof(ex));
419 	seekx(fd, hdr->size);
420 	break;
421     case F_ELF:
422 	eh = elfhdr;
423 	eh.e.e_entry = htole32(hdr->entry);
424 	eh.p[0].p_vaddr = eh.p[0].p_paddr = htole32(hdr->org);
425 	eh.p[0].p_filesz = eh.p[0].p_memsz = htole32(hdr->text);
426 	eh.p[1].p_offset = htole32(le32toh(eh.p[0].p_offset) +
427 	    le32toh(eh.p[0].p_filesz));
428 	eh.p[1].p_vaddr = eh.p[1].p_paddr =
429 	    htole32(roundup2(le32toh(eh.p[0].p_paddr) + le32toh(eh.p[0].p_memsz),
430 	    4096));
431 	eh.p[1].p_filesz = eh.p[1].p_memsz = htole32(hdr->data);
432 	eh.sh[2].sh_addr = eh.p[0].p_vaddr;
433 	eh.sh[2].sh_offset = eh.p[0].p_offset;
434 	eh.sh[2].sh_size = eh.p[0].p_filesz;
435 	eh.sh[3].sh_addr = eh.p[1].p_vaddr;
436 	eh.sh[3].sh_offset = eh.p[1].p_offset;
437 	eh.sh[3].sh_size = eh.p[1].p_filesz;
438 	writex(fd, &eh, sizeof(eh));
439 	hdr->size = sizeof(eh);
440     }
441 }
442 
443 /*
444  * Safe copy from input file to output file.
445  */
446 static void
447 copy(int fdi, int fdo, size_t nbyte, off_t offset)
448 {
449     char buf[8192];
450     size_t n;
451 
452     while (nbyte) {
453 	if ((n = sizeof(buf)) > nbyte)
454 	    n = nbyte;
455 	if (readx(fdi, buf, n, offset) != n)
456 	    errx(2, "%s: Short read", fname);
457 	writex(fdo, buf, n);
458 	nbyte -= n;
459 	offset = -1;
460     }
461 }
462 
463 /*
464  * Safe read from input file.
465  */
466 static size_t
467 readx(int fd, void *buf, size_t nbyte, off_t offset)
468 {
469     ssize_t n;
470 
471     if (offset != -1 && lseek(fd, offset, SEEK_SET) != offset)
472 	err(2, "%s", fname);
473     if ((n = read(fd, buf, nbyte)) == -1)
474 	err(2, "%s", fname);
475     return n;
476 }
477 
478 /*
479  * Safe write to output file.
480  */
481 static void
482 writex(int fd, const void *buf, size_t nbyte)
483 {
484     ssize_t n;
485 
486     if ((n = write(fd, buf, nbyte)) == -1)
487 	err(2, "%s", tname);
488     if ((size_t)n != nbyte)
489 	errx(2, "%s: Short write", tname);
490 }
491 
492 /*
493  * Safe seek in output file.
494  */
495 static void
496 seekx(int fd, off_t offset)
497 {
498     if (lseek(fd, offset, SEEK_SET) != offset)
499 	err(2, "%s", tname);
500 }
501 
502 /*
503  * Convert an option argument to a format code.
504  */
505 static unsigned int
506 optfmt(const char *arg)
507 {
508     unsigned int i;
509 
510     for (i = 0; i < F_CNT && strcmp(arg, fmtlist[i]); i++);
511     if (i == F_CNT)
512 	errx(1, "%s: Unknown format", arg);
513     return i;
514 }
515 
516 /*
517  * Convert an option argument to an address.
518  */
519 static uint32_t
520 optaddr(const char *arg)
521 {
522     char *s;
523     unsigned long x;
524 
525     errno = 0;
526     x = strtoul(arg, &s, 0);
527     if (errno || !*arg || *s || x > MAXU32)
528 	errx(1, "%s: Illegal address", arg);
529     return x;
530 }
531 
532 /*
533  * Convert an option argument to a page number.
534  */
535 static int
536 optpage(const char *arg, int hi)
537 {
538     char *s;
539     long x;
540 
541     errno = 0;
542     x = strtol(arg, &s, 0);
543     if (errno || !*arg || *s || x < 0 || x > hi)
544 	errx(1, "%s: Illegal page number", arg);
545     return x;
546 }
547 
548 /*
549  * Display a warning.
550  */
551 static void
552 Warn(const char *locus, const char *fmt, ...)
553 {
554     va_list ap;
555     char *s;
556 
557     if (!quiet) {
558 	asprintf(&s, "%s: Warning: %s", locus, fmt);
559 	va_start(ap, fmt);
560 	vwarnx(s, ap);
561 	va_end(ap);
562 	free(s);
563     }
564 }
565 
566 /*
567  * Display usage information.
568  */
569 static void
570 usage(void)
571 {
572     fprintf(stderr, "%s\n%s\n",
573     "usage: btxld [-qv] [-b file] [-E address] [-e address] [-f format]",
574     "             [-l file] [-o filename] [-P page] [-W page] file");
575     exit(1);
576 }
577