1 /*-
2  * Copyright (c) 1999 Global Technology Associates, Inc.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
18  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
19  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
20  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
21  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
23  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
24  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: stable/9/sys/boot/i386/kgzldr/boot.c 119482 2003-08-25 23:28:32Z obrien $");
29 
30 #include <sys/types.h>
31 #include <sys/reboot.h>
32 #include <sys/inflate.h>
33 
34 #include "kgzldr.h"
35 
36 #define KGZ_HEAD   0xa          /* leading bytes to ignore */
37 #define KGZ_TAIL   0x8          /* trailing bytes to ignore */
38 
39 #define E_FMT  1		/* Error: Invalid format */
40 #define E_MEM  2		/* Error: Out of memory */
41 
42 struct kgz_hdr {
43     char	ident[4];	/* identification */
44     uint32_t	dload;		/* decoded image load address */
45     uint32_t	dsize;		/* decoded image size */
46     uint32_t	isize;		/* image size in memory */
47     uint32_t	entry;		/* program entry point */
48     uint32_t	nsize;		/* encoded image size */
49 };
50 extern struct kgz_hdr kgz;	/* header */
51 extern uint8_t kgz_ndata[];	/* encoded image */
52 
53 static const char *const msg[] = {
54     "done",
55     "invalid format",
56     "out of memory"
57 };
58 
59 static const u_char *ip;        /* input pointer */
60 static u_char *op;              /* output pointer */
61 
62 static struct inflate infl;	/* inflate() parameters */
63 
64 static int decode(void);
65 static int input(void *);
66 static int output(void *, u_char *, u_long);
67 
68 /*
69  * Uncompress and boot a kernel.
70  */
71 int
boot(int howto)72 boot(int howto)
73 {
74     int err;
75 
76     kgz_con = howto & RB_SERIAL ? KGZ_SIO : KGZ_CRT;
77     putstr("Uncompressing ... ");
78     err = decode();
79     putstr(msg[err]);
80     putstr("\n");
81     if (err) {
82         putstr("System halted");
83 	for (;;)
84 	    ;
85     }
86     return err;
87 }
88 
89 /*
90  * Interface with inflate() to uncompress the data.
91  */
92 static int
decode(void)93 decode(void)
94 {
95     static u_char slide[GZ_WSIZE];
96     int err;
97 
98     ip = kgz_ndata + KGZ_HEAD;
99     op = (u_char *)kgz.dload;
100     infl.gz_input = input;
101     infl.gz_output = output;
102     infl.gz_slide = slide;
103     err = inflate(&infl);
104     return err ? err == 3 ? E_MEM : E_FMT : 0;
105 }
106 
107 /*
108  * Read a byte.
109  */
110 static int
input(void * dummy)111 input(void *dummy)
112 {
113     if ((size_t)(ip - kgz_ndata) + KGZ_TAIL > kgz.nsize)
114         return GZ_EOF;
115     return *ip++;
116 }
117 
118 /*
119  * Write some bytes.
120  */
121 static int
output(void * dummy,u_char * ptr,u_long len)122 output(void *dummy, u_char * ptr, u_long len)
123 {
124     if (op - (u_char *)kgz.dload + len > kgz.dsize)
125         return -1;
126     while (len--)
127         *op++ = *ptr++;
128     return 0;
129 }
130