src/file/file.c

/*
 *  Copyright (C) 2003-2007  Anders Gavare.  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright  
 *     notice, this list of conditions and the following disclaimer in the 
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE   
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 *  SUCH DAMAGE.
 *
 *
 *  $Id: file.c,v 1.4 2007/05/22 09:49:31 debug Exp $
 *
 *  This module contains functions which load executable images into (emulated)
 *  memory. File formats recognized so far are:
 *
 *      a.out           traditional old-style Unix binary format
 *      Mach-O          MacOS X format, etc.
 *      ecoff           old format used by Ultrix, Windows NT, etc
 *      srec            Motorola SREC format
 *      raw             raw binaries, "address:[skiplen:[entrypoint:]]filename"
 *      ELF             32-bit and 64-bit ELFs
 *
 *  If a file is not of one of the above mentioned formats, it is assumed
 *  to be symbol data generated by 'nm' or 'nm -S'.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>

#include "cpu.h"
#include "machine.h"
#include "memory.h"
#include "misc.h"
#include "symbol.h"


extern int quiet_mode;
extern int verbose;


/*
 *  This should be increased by every routine here that actually loads an
 *  executable file into memory.  (For example, loading a symbol file should
 *  NOT increase this.)
 */
static int n_executables_loaded = 0;


#include "exec_elf.h"           /*  Ugly; needed for ELFDATA2LSB etc.  */

#define unencode(var,dataptr,typ)       {                               \
                int Wi;  unsigned char Wb;                              \
                unsigned char *Wp = (unsigned char *) dataptr;          \
                int Wlen = sizeof(typ);                                 \
                var = 0;                                                \
                for (Wi=0; Wi<Wlen; Wi++) {                             \
                        if (encoding == ELFDATA2LSB)                    \
                                Wb = Wp[Wlen-1 - Wi];                   \
                        else                                            \
                                Wb = Wp[Wi];                            \
                        if (Wi == 0 && (Wb & 0x80)) {                   \
                                var --; /*  set var to -1 :-)  */       \
                                var <<= 8;                              \
                        }                                               \
                        var |= Wb;                                      \
                        if (Wi < Wlen-1)                                \
                                var <<= 8;                              \
                }                                                       \
        }


#include "file_aout.c"
#include "file_ecoff.c"
#include "file_elf.c"
#include "file_macho.c"
#include "file_raw.c"
#include "file_srec.c"


/*
 *  file_n_executables_loaded():
 *
 *  Returns the number of executable files loaded into emulated memory.
 */
int file_n_executables_loaded(void)
{
        return n_executables_loaded;
}


/*
 *  file_load():
 *
 *  Sense the file format of a file (ELF, a.out, ecoff), and call the
 *  right file_load_XXX() function.  If the file isn't of a recognized
 *  binary format, assume that it contains symbol definitions.
 *
 *  If the filename doesn't exist, try to treat the name as
 *   "address:filename" and load the file as a raw binary.
 */
void file_load(struct machine *machine, struct memory *mem,
        char *filename, uint64_t *entrypointp,
        int arch, uint64_t *gpp, int *byte_orderp, uint64_t *tocp)
{
        int iadd = DEBUG_INDENTATION, old_quiet_mode;
        FILE *f;
        unsigned char buf[12];
        unsigned char buf2[2];
        size_t len, len2, i;
        off_t size;

        if (byte_orderp == NULL) {
                fprintf(stderr, "file_load(): byte_order == NULL\n");
                exit(1);
        }

        if (arch == ARCH_NOARCH) {
                fprintf(stderr, "file_load(): FATAL ERROR: no arch?\n");
                exit(1);
        }

        if (mem == NULL || filename == NULL) {
                fprintf(stderr, "file_load(): mem or filename is NULL\n");
                exit(1);
        }

        /*  Skip configuration files:  */
        if (filename[0] == '@')
                return;

        debug("loading %s%s\n", filename, verbose >= 2? ":" : "");
        debug_indentation(iadd);

        old_quiet_mode = quiet_mode;
        if (verbose < 2)
                quiet_mode = 1;

        f = fopen(filename, "r");
        if (f == NULL) {
                file_load_raw(machine, mem, filename, entrypointp);
                goto ret;
        }

        fseek(f, 0, SEEK_END);
        size = ftello(f);
        fseek(f, 0, SEEK_SET);

        memset(buf, 0, sizeof(buf));
        len = fread(buf, 1, sizeof(buf), f);
        fseek(f, 510, SEEK_SET);
        len2 = fread(buf2, 1, sizeof(buf2), f);
        fclose(f);

        if (len < (signed int)sizeof(buf)) {
                fprintf(stderr, "\nThis file is too small to contain "
                    "anything useful\n");
                exit(1);
        }

        /*  Is it an ELF?  */
        if (buf[0] == 0x7f && buf[1]=='E' && buf[2]=='L' && buf[3]=='F') {
                file_load_elf(machine, mem, filename,
                    entrypointp, arch, gpp, byte_orderp, tocp);
                goto ret;
        }

        /*  Is it an a.out?  */
        if (buf[0]==0x00 && buf[1]==0x8b && buf[2]==0x01 && buf[3]==0x07) {
                /*  MIPS a.out  */
                file_load_aout(machine, mem, filename, 0,
                    entrypointp, arch, byte_orderp);
                goto ret;
        }
        if (buf[0]==0x00 && buf[1]==0x87 && buf[2]==0x01 && buf[3]==0x08) {
                /*  M68K a.out  */
                file_load_aout(machine, mem, filename,
                    AOUT_FLAG_VADDR_ZERO_HACK  /*  for OpenBSD/mac68k  */,
                    entrypointp, arch, byte_orderp);
                goto ret;
        }
        if (buf[0]==0x00 && buf[1]==0x99 && buf[2]==0x01 && buf[3]==0x0b) {
                /*  OpenBSD/M88K a.out  */
                file_load_aout(machine, mem, filename, AOUT_FLAG_FROM_BEGINNING,
                    entrypointp, arch, byte_orderp);
                goto ret;
        }
        if (buf[0]==0x00 && buf[1]==0x8f && buf[2]==0x01 && buf[3]==0x0b) {
                /*  ARM a.out  */
                file_load_aout(machine, mem, filename, AOUT_FLAG_FROM_BEGINNING,
                    entrypointp, arch, byte_orderp);
                goto ret;
        }
        if (buf[0]==0x00 && buf[1]==0x86 && buf[2]==0x01 && buf[3]==0x0b) {
                /*  i386 a.out (old OpenBSD and NetBSD etc)  */
                file_load_aout(machine, mem, filename, AOUT_FLAG_FROM_BEGINNING,
                    entrypointp, arch, byte_orderp);
                goto ret;
        }
        if (buf[0]==0x01 && buf[1]==0x03 && buf[2]==0x01 && buf[3]==0x07) {
                /*  SPARC a.out (old 32-bit NetBSD etc)  */
                file_load_aout(machine, mem, filename, AOUT_FLAG_NO_SIZES,
                    entrypointp, arch, byte_orderp);
                goto ret;
        }
        if (buf[0]==0x00 && buf[2]==0x00 && buf[8]==0x7a && buf[9]==0x75) {
                /*  DEC OSF1 on MIPS:  */
                file_load_aout(machine, mem, filename, AOUT_FLAG_DECOSF1,
                    entrypointp, arch, byte_orderp);
                goto ret;
        }

        /*
         *  Is it a Mach-O file?
         */
        if (buf[0] == 0xfe && buf[1] == 0xed && buf[2] == 0xfa &&
            (buf[3] == 0xce || buf[3] == 0xcf)) {
                file_load_macho(machine, mem, filename, entrypointp,
                    arch, byte_orderp, buf[3] == 0xcf, 0);
                goto ret;
        }
        if ((buf[0] == 0xce || buf[0] == 0xcf) && buf[1] == 0xfa &&
            buf[2] == 0xed && buf[3] == 0xfe) {
                file_load_macho(machine, mem, filename, entrypointp,
                    arch, byte_orderp, buf[0] == 0xcf, 1);
                goto ret;
        }

        /*
         *  Is it an ecoff?
         *
         *  TODO: What's the deal with the magic value's byte order? Sometimes
         *  it seems to be reversed for BE when compared to LE, but not always?
         */
        if (buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEB ||
            buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEL ||
            buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEB2 ||
            buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEL2 ||
            buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEB3 ||
            buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEL3 ||
            buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEB ||
            buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEL ||
            buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEB2 ||
            buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEL2 ||
            buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEB3 ||
            buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEL3) {
                file_load_ecoff(machine, mem, filename, entrypointp,
                    arch, gpp, byte_orderp);
                goto ret;
        }

        /*  Is it a Motorola SREC file?  */
        if ((buf[0]=='S' && buf[1]>='0' && buf[1]<='9')) {
                file_load_srec(machine, mem, filename, entrypointp);
                goto ret;
        }

        /*  gzipped files are not supported:  */
        if (buf[0]==0x1f && buf[1]==0x8b) {
                fprintf(stderr, "\nYou need to gunzip the file before you"
                    " try to use it.\n");
                exit(1);
        }

        if (size > 24000000) {
                fprintf(stderr, "\nThis file is very large (%lli bytes)\n",
                    (long long)size);
                fprintf(stderr, "Are you sure it is a kernel and not a disk "
                    "image? (Use the -d option.)\n");
                exit(1);
        }

        if (size == 1474560)
                fprintf(stderr, "Hm... this file is the size of a 1.44 MB "
                    "floppy image. Maybe you forgot the\n-d switch?\n");

        /*
         *  Ugly hack for Dreamcast:  When booting from a Dreamcast CDROM
         *  image, a temporary file is extracted into /tmp/gxemul.*, but this
         *  is a "scrambled" raw binary. This code unscrambles it, and loads
         *  it as a raw binary.
         */
        if (machine->machine_type == MACHINE_DREAMCAST &&
            strncmp(filename, "/tmp/gxemul.", 12) == 0) {
                char *tmp_filename = malloc(strlen(filename) + 100);
                snprintf(tmp_filename, strlen(filename) + 100,
                    "%s.descrambled", filename);
                debug("descrambling into %s\n", tmp_filename);
                dreamcast_descramble(filename, tmp_filename);

                snprintf(tmp_filename, strlen(filename) + 100,
                    "0x8c010000:%s.descrambled", filename);
                debug("loading descrambled Dreamcast binary\n");
                file_load_raw(machine, mem, tmp_filename, entrypointp);

                snprintf(tmp_filename, strlen(filename) + 100,
                    "%s.descrambled", filename);
                remove(tmp_filename);
                free(tmp_filename);

                /*  Hack: Start a "boot from CDROM" sequence:  */
                *entrypointp = 0x8c000080;
                goto ret;
        }

        /*
         *  Last resort:  symbol definitions from nm (or nm -S):
         *
         *  If the buf contains typical 'binary' characters, then print
         *  an error message and quit instead of assuming that it is a
         *  symbol file.
         */
        for (i=0; i<(signed)sizeof(buf); i++)
                if (buf[i] < 32 && buf[i] != '\t' &&
                    buf[i] != '\n' && buf[i] != '\r' &&
                    buf[i] != '\f') {
                        fprintf(stderr, "\nThe file format of '%s' is "
                            "unknown.\n\n ", filename);
                        for (i=0; i<(signed)sizeof(buf); i++)
                                fprintf(stderr, " %02x", buf[i]);

                        if (len2 == 2 && buf2[0] == 0x55 && buf2[1] == 0xaa)
                                fprintf(stderr, "\n\nIt has a PC-style "
                                    "bootsector marker.");

                        fprintf(stderr, "\n\nPossible explanations:\n\n"
                            "  o)  If this is a disk image, you forgot '-d' "
                            "on the command line.\n"
                            "  o)  You are attempting to load a raw binary "
                            "into emulated memory,\n"
                            "      but forgot to add the address prefix.\n"
                            "  o)  This is an unsupported binary format.\n\n");
                        exit(1);
                }

        symbol_readfile(&machine->symbol_context, filename);

ret:
        debug_indentation(-iadd);
        quiet_mode = old_quiet_mode;
}

1	/*
2	* Copyright (C) 2003-2007 Anders Gavare. All rights reserved.
3	*
4	* Redistribution and use in source and binary forms, with or without
5	* modification, are permitted provided that the following conditions are met:
6	*
7	* 1. Redistributions of source code must retain the above copyright
8	* notice, this list of conditions and the following disclaimer.
9	* 2. Redistributions in binary form must reproduce the above copyright
10	* notice, this list of conditions and the following disclaimer in the
11	* documentation and/or other materials provided with the distribution.
12	* 3. The name of the author may not be used to endorse or promote products
13	* derived from this software without specific prior written permission.
14	*
15	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25	* SUCH DAMAGE.
26	*
27	*
28	* $Id: file.c,v 1.4 2007/05/22 09:49:31 debug Exp $
29	*
30	* This module contains functions which load executable images into (emulated)
31	* memory. File formats recognized so far are:
32	*
33	* a.out traditional old-style Unix binary format
34	* Mach-O MacOS X format, etc.
35	* ecoff old format used by Ultrix, Windows NT, etc
36	* srec Motorola SREC format
37	* raw raw binaries, "address:[skiplen:[entrypoint:]]filename"
38	* ELF 32-bit and 64-bit ELFs
39	*
40	* If a file is not of one of the above mentioned formats, it is assumed
41	* to be symbol data generated by 'nm' or 'nm -S'.
42	*/
43
44	#include <stdio.h>
45	#include <stdlib.h>
46	#include <string.h>
47	#include <sys/types.h>
48
49	#include "cpu.h"
50	#include "machine.h"
51	#include "memory.h"
52	#include "misc.h"
53	#include "symbol.h"
54
55
56	extern int quiet_mode;
57	extern int verbose;
58
59
60	/*
61	* This should be increased by every routine here that actually loads an
62	* executable file into memory. (For example, loading a symbol file should
63	* NOT increase this.)
64	*/
65	static int n_executables_loaded = 0;
66
67
68	#include "exec_elf.h" /* Ugly; needed for ELFDATA2LSB etc. */
69
70	#define unencode(var,dataptr,typ) { \
71	int Wi; unsigned char Wb; \
72	unsigned char Wp = (unsigned char ) dataptr; \
73	int Wlen = sizeof(typ); \
74	var = 0; \
75	for (Wi=0; Wi<Wlen; Wi++) { \
76	if (encoding == ELFDATA2LSB) \
77	Wb = Wp[Wlen-1 - Wi]; \
78	else \
79	Wb = Wp[Wi]; \
80	if (Wi == 0 && (Wb & 0x80)) { \
81	var --; /* set var to -1 :-) */ \
82	var <<= 8; \
83	} \
84	var \|= Wb; \
85	if (Wi < Wlen-1) \
86	var <<= 8; \
87	} \
88	}
89
90
91	#include "file_aout.c"
92	#include "file_ecoff.c"
93	#include "file_elf.c"
94	#include "file_macho.c"
95	#include "file_raw.c"
96	#include "file_srec.c"
97
98
99	/*
100	* file_n_executables_loaded():
101	*
102	* Returns the number of executable files loaded into emulated memory.
103	*/
104	int file_n_executables_loaded(void)
105	{
106	return n_executables_loaded;
107	}
108
109
110	/*
111	* file_load():
112	*
113	* Sense the file format of a file (ELF, a.out, ecoff), and call the
114	* right file_load_XXX() function. If the file isn't of a recognized
115	* binary format, assume that it contains symbol definitions.
116	*
117	* If the filename doesn't exist, try to treat the name as
118	* "address:filename" and load the file as a raw binary.
119	*/
120	void file_load(struct machine machine, struct memory mem,
121	char filename, uint64_t entrypointp,
122	int arch, uint64_t gpp, int byte_orderp, uint64_t *tocp)
123	{
124	int iadd = DEBUG_INDENTATION, old_quiet_mode;
125	FILE *f;
126	unsigned char buf[12];
127	unsigned char buf2[2];
128	size_t len, len2, i;
129	off_t size;
130
131	if (byte_orderp == NULL) {
132	fprintf(stderr, "file_load(): byte_order == NULL\n");
133	exit(1);
134	}
135
136	if (arch == ARCH_NOARCH) {
137	fprintf(stderr, "file_load(): FATAL ERROR: no arch?\n");
138	exit(1);
139	}
140
141	if (mem == NULL \|\| filename == NULL) {
142	fprintf(stderr, "file_load(): mem or filename is NULL\n");
143	exit(1);
144	}
145
146	/* Skip configuration files: */
147	if (filename[0] == '@')
148	return;
149
150	debug("loading %s%s\n", filename, verbose >= 2? ":" : "");
151	debug_indentation(iadd);
152
153	old_quiet_mode = quiet_mode;
154	if (verbose < 2)
155	quiet_mode = 1;
156
157	f = fopen(filename, "r");
158	if (f == NULL) {
159	file_load_raw(machine, mem, filename, entrypointp);
160	goto ret;
161	}
162
163	fseek(f, 0, SEEK_END);
164	size = ftello(f);
165	fseek(f, 0, SEEK_SET);
166
167	memset(buf, 0, sizeof(buf));
168	len = fread(buf, 1, sizeof(buf), f);
169	fseek(f, 510, SEEK_SET);
170	len2 = fread(buf2, 1, sizeof(buf2), f);
171	fclose(f);
172
173	if (len < (signed int)sizeof(buf)) {
174	fprintf(stderr, "\nThis file is too small to contain "
175	"anything useful\n");
176	exit(1);
177	}
178
179	/* Is it an ELF? */
180	if (buf[0] == 0x7f && buf[1]=='E' && buf[2]=='L' && buf[3]=='F') {
181	file_load_elf(machine, mem, filename,
182	entrypointp, arch, gpp, byte_orderp, tocp);
183	goto ret;
184	}
185
186	/* Is it an a.out? */
187	if (buf[0]==0x00 && buf[1]==0x8b && buf[2]==0x01 && buf[3]==0x07) {
188	/* MIPS a.out */
189	file_load_aout(machine, mem, filename, 0,
190	entrypointp, arch, byte_orderp);
191	goto ret;
192	}
193	if (buf[0]==0x00 && buf[1]==0x87 && buf[2]==0x01 && buf[3]==0x08) {
194	/* M68K a.out */
195	file_load_aout(machine, mem, filename,
196	AOUT_FLAG_VADDR_ZERO_HACK /* for OpenBSD/mac68k */,
197	entrypointp, arch, byte_orderp);
198	goto ret;
199	}
200	if (buf[0]==0x00 && buf[1]==0x99 && buf[2]==0x01 && buf[3]==0x0b) {
201	/* OpenBSD/M88K a.out */
202	file_load_aout(machine, mem, filename, AOUT_FLAG_FROM_BEGINNING,
203	entrypointp, arch, byte_orderp);
204	goto ret;
205	}
206	if (buf[0]==0x00 && buf[1]==0x8f && buf[2]==0x01 && buf[3]==0x0b) {
207	/* ARM a.out */
208	file_load_aout(machine, mem, filename, AOUT_FLAG_FROM_BEGINNING,
209	entrypointp, arch, byte_orderp);
210	goto ret;
211	}
212	if (buf[0]==0x00 && buf[1]==0x86 && buf[2]==0x01 && buf[3]==0x0b) {
213	/* i386 a.out (old OpenBSD and NetBSD etc) */
214	file_load_aout(machine, mem, filename, AOUT_FLAG_FROM_BEGINNING,
215	entrypointp, arch, byte_orderp);
216	goto ret;
217	}
218	if (buf[0]==0x01 && buf[1]==0x03 && buf[2]==0x01 && buf[3]==0x07) {
219	/* SPARC a.out (old 32-bit NetBSD etc) */
220	file_load_aout(machine, mem, filename, AOUT_FLAG_NO_SIZES,
221	entrypointp, arch, byte_orderp);
222	goto ret;
223	}
224	if (buf[0]==0x00 && buf[2]==0x00 && buf[8]==0x7a && buf[9]==0x75) {
225	/* DEC OSF1 on MIPS: */
226	file_load_aout(machine, mem, filename, AOUT_FLAG_DECOSF1,
227	entrypointp, arch, byte_orderp);
228	goto ret;
229	}
230
231	/*
232	* Is it a Mach-O file?
233	*/
234	if (buf[0] == 0xfe && buf[1] == 0xed && buf[2] == 0xfa &&
235	(buf[3] == 0xce \|\| buf[3] == 0xcf)) {
236	file_load_macho(machine, mem, filename, entrypointp,
237	arch, byte_orderp, buf[3] == 0xcf, 0);
238	goto ret;
239	}
240	if ((buf[0] == 0xce \|\| buf[0] == 0xcf) && buf[1] == 0xfa &&
241	buf[2] == 0xed && buf[3] == 0xfe) {
242	file_load_macho(machine, mem, filename, entrypointp,
243	arch, byte_orderp, buf[0] == 0xcf, 1);
244	goto ret;
245	}
246
247	/*
248	* Is it an ecoff?
249	*
250	* TODO: What's the deal with the magic value's byte order? Sometimes
251	* it seems to be reversed for BE when compared to LE, but not always?
252	*/
253	if (buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEB \|\|
254	buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEL \|\|
255	buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEB2 \|\|
256	buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEL2 \|\|
257	buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEB3 \|\|
258	buf[0]+256*buf[1] == ECOFF_MAGIC_MIPSEL3 \|\|
259	buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEB \|\|
260	buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEL \|\|
261	buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEB2 \|\|
262	buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEL2 \|\|
263	buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEB3 \|\|
264	buf[1]+256*buf[0] == ECOFF_MAGIC_MIPSEL3) {
265	file_load_ecoff(machine, mem, filename, entrypointp,
266	arch, gpp, byte_orderp);
267	goto ret;
268	}
269
270	/* Is it a Motorola SREC file? */
271	if ((buf[0]=='S' && buf[1]>='0' && buf[1]<='9')) {
272	file_load_srec(machine, mem, filename, entrypointp);
273	goto ret;
274	}
275
276	/* gzipped files are not supported: */
277	if (buf[0]==0x1f && buf[1]==0x8b) {
278	fprintf(stderr, "\nYou need to gunzip the file before you"
279	" try to use it.\n");
280	exit(1);
281	}
282
283	if (size > 24000000) {
284	fprintf(stderr, "\nThis file is very large (%lli bytes)\n",
285	(long long)size);
286	fprintf(stderr, "Are you sure it is a kernel and not a disk "
287	"image? (Use the -d option.)\n");
288	exit(1);
289	}
290
291	if (size == 1474560)
292	fprintf(stderr, "Hm... this file is the size of a 1.44 MB "
293	"floppy image. Maybe you forgot the\n-d switch?\n");
294
295	/*
296	* Ugly hack for Dreamcast: When booting from a Dreamcast CDROM
297	* image, a temporary file is extracted into /tmp/gxemul.*, but this
298	* is a "scrambled" raw binary. This code unscrambles it, and loads
299	* it as a raw binary.
300	*/
301	if (machine->machine_type == MACHINE_DREAMCAST &&
302	strncmp(filename, "/tmp/gxemul.", 12) == 0) {
303	char *tmp_filename = malloc(strlen(filename) + 100);
304	snprintf(tmp_filename, strlen(filename) + 100,
305	"%s.descrambled", filename);
306	debug("descrambling into %s\n", tmp_filename);
307	dreamcast_descramble(filename, tmp_filename);
308
309	snprintf(tmp_filename, strlen(filename) + 100,
310	"0x8c010000:%s.descrambled", filename);
311	debug("loading descrambled Dreamcast binary\n");
312	file_load_raw(machine, mem, tmp_filename, entrypointp);
313
314	snprintf(tmp_filename, strlen(filename) + 100,
315	"%s.descrambled", filename);
316	remove(tmp_filename);
317	free(tmp_filename);
318
319	/* Hack: Start a "boot from CDROM" sequence: */
320	*entrypointp = 0x8c000080;
321	goto ret;
322	}
323
324	/*
325	* Last resort: symbol definitions from nm (or nm -S):
326	*
327	* If the buf contains typical 'binary' characters, then print
328	* an error message and quit instead of assuming that it is a
329	* symbol file.
330	*/
331	for (i=0; i<(signed)sizeof(buf); i++)
332	if (buf[i] < 32 && buf[i] != '\t' &&
333	buf[i] != '\n' && buf[i] != '\r' &&
334	buf[i] != '\f') {
335	fprintf(stderr, "\nThe file format of '%s' is "
336	"unknown.\n\n ", filename);
337	for (i=0; i<(signed)sizeof(buf); i++)
338	fprintf(stderr, " %02x", buf[i]);
339
340	if (len2 == 2 && buf2[0] == 0x55 && buf2[1] == 0xaa)
341	fprintf(stderr, "\n\nIt has a PC-style "
342	"bootsector marker.");
343
344	fprintf(stderr, "\n\nPossible explanations:\n\n"
345	" o) If this is a disk image, you forgot '-d' "
346	"on the command line.\n"
347	" o) You are attempting to load a raw binary "
348	"into emulated memory,\n"
349	" but forgot to add the address prefix.\n"
350	" o) This is an unsupported binary format.\n\n");
351	exit(1);
352	}
353
354	symbol_readfile(&machine->symbol_context, filename);
355
356	ret:
357	debug_indentation(-iadd);
358	quiet_mode = old_quiet_mode;
359	}
360