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1 | Java(tm) Binary Kernel Support for Linux v1.03 | |
2 | ---------------------------------------------- | |
3 | ||
4 | Linux beats them ALL! While all other OS's are TALKING about direct | |
5 | support of Java Binaries in the OS, Linux is doing it! | |
6 | ||
7 | You can execute Java applications and Java Applets just like any | |
8 | other program after you have done the following: | |
9 | ||
10 | 1) You MUST FIRST install the Java Developers Kit for Linux. | |
11 | The Java on Linux HOWTO gives the details on getting and | |
12 | installing this. This HOWTO can be found at: | |
13 | ||
14 | ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/Java-HOWTO | |
15 | ||
16 | You should also set up a reasonable CLASSPATH environment | |
17 | variable to use Java applications that make use of any | |
18 | nonstandard classes (not included in the same directory | |
19 | as the application itself). | |
20 | ||
21 | 2) You have to compile BINFMT_MISC either as a module or into | |
22 | the kernel (CONFIG_BINFMT_MISC) and set it up properly. | |
23 | If you choose to compile it as a module, you will have | |
24 | to insert it manually with modprobe/insmod, as kmod | |
25 | cannot easily be supported with binfmt_misc. | |
26 | Read the file 'binfmt_misc.txt' in this directory to know | |
27 | more about the configuration process. | |
28 | ||
29 | 3) Add the following configuration items to binfmt_misc | |
30 | (you should really have read binfmt_misc.txt now): | |
31 | support for Java applications: | |
32 | ':Java:M::\xca\xfe\xba\xbe::/usr/local/bin/javawrapper:' | |
33 | support for executable Jar files: | |
34 | ':ExecutableJAR:E::jar::/usr/local/bin/jarwrapper:' | |
35 | support for Java Applets: | |
36 | ':Applet:E::html::/usr/bin/appletviewer:' | |
37 | or the following, if you want to be more selective: | |
38 | ':Applet:M::<!--applet::/usr/bin/appletviewer:' | |
39 | ||
40 | Of course you have to fix the path names. The path/file names given in this | |
41 | document match the Debian 2.1 system. (i.e. jdk installed in /usr, | |
42 | custom wrappers from this document in /usr/local) | |
43 | ||
44 | Note, that for the more selective applet support you have to modify | |
45 | existing html-files to contain <!--applet--> in the first line | |
46 | ('<' has to be the first character!) to let this work! | |
47 | ||
48 | For the compiled Java programs you need a wrapper script like the | |
49 | following (this is because Java is broken in case of the filename | |
50 | handling), again fix the path names, both in the script and in the | |
51 | above given configuration string. | |
52 | ||
53 | You, too, need the little program after the script. Compile like | |
54 | gcc -O2 -o javaclassname javaclassname.c | |
55 | and stick it to /usr/local/bin. | |
56 | ||
57 | Both the javawrapper shellscript and the javaclassname program | |
58 | were supplied by Colin J. Watson <cjw44@cam.ac.uk>. | |
59 | ||
60 | ====================== Cut here =================== | |
61 | #!/bin/bash | |
62 | # /usr/local/bin/javawrapper - the wrapper for binfmt_misc/java | |
63 | ||
64 | if [ -z "$1" ]; then | |
65 | exec 1>&2 | |
66 | echo Usage: $0 class-file | |
67 | exit 1 | |
68 | fi | |
69 | ||
70 | CLASS=$1 | |
71 | FQCLASS=`/usr/local/bin/javaclassname $1` | |
72 | FQCLASSN=`echo $FQCLASS | sed -e 's/^.*\.\([^.]*\)$/\1/'` | |
73 | FQCLASSP=`echo $FQCLASS | sed -e 's-\.-/-g' -e 's-^[^/]*$--' -e 's-/[^/]*$--'` | |
74 | ||
75 | # for example: | |
76 | # CLASS=Test.class | |
77 | # FQCLASS=foo.bar.Test | |
78 | # FQCLASSN=Test | |
79 | # FQCLASSP=foo/bar | |
80 | ||
81 | unset CLASSBASE | |
82 | ||
83 | declare -i LINKLEVEL=0 | |
84 | ||
85 | while :; do | |
86 | if [ "`basename $CLASS .class`" == "$FQCLASSN" ]; then | |
87 | # See if this directory works straight off | |
88 | cd -L `dirname $CLASS` | |
89 | CLASSDIR=$PWD | |
90 | cd $OLDPWD | |
91 | if echo $CLASSDIR | grep -q "$FQCLASSP$"; then | |
92 | CLASSBASE=`echo $CLASSDIR | sed -e "s.$FQCLASSP$.."` | |
93 | break; | |
94 | fi | |
95 | # Try dereferencing the directory name | |
96 | cd -P `dirname $CLASS` | |
97 | CLASSDIR=$PWD | |
98 | cd $OLDPWD | |
99 | if echo $CLASSDIR | grep -q "$FQCLASSP$"; then | |
100 | CLASSBASE=`echo $CLASSDIR | sed -e "s.$FQCLASSP$.."` | |
101 | break; | |
102 | fi | |
103 | # If no other possible filename exists | |
104 | if [ ! -L $CLASS ]; then | |
105 | exec 1>&2 | |
106 | echo $0: | |
107 | echo " $CLASS should be in a" \ | |
108 | "directory tree called $FQCLASSP" | |
109 | exit 1 | |
110 | fi | |
111 | fi | |
112 | if [ ! -L $CLASS ]; then break; fi | |
113 | # Go down one more level of symbolic links | |
114 | let LINKLEVEL+=1 | |
115 | if [ $LINKLEVEL -gt 5 ]; then | |
116 | exec 1>&2 | |
117 | echo $0: | |
118 | echo " Too many symbolic links encountered" | |
119 | exit 1 | |
120 | fi | |
121 | CLASS=`ls --color=no -l $CLASS | sed -e 's/^.* \([^ ]*\)$/\1/'` | |
122 | done | |
123 | ||
124 | if [ -z "$CLASSBASE" ]; then | |
125 | if [ -z "$FQCLASSP" ]; then | |
126 | GOODNAME=$FQCLASSN.class | |
127 | else | |
128 | GOODNAME=$FQCLASSP/$FQCLASSN.class | |
129 | fi | |
130 | exec 1>&2 | |
131 | echo $0: | |
132 | echo " $FQCLASS should be in a file called $GOODNAME" | |
133 | exit 1 | |
134 | fi | |
135 | ||
136 | if ! echo $CLASSPATH | grep -q "^\(.*:\)*$CLASSBASE\(:.*\)*"; then | |
137 | # class is not in CLASSPATH, so prepend dir of class to CLASSPATH | |
138 | if [ -z "${CLASSPATH}" ] ; then | |
139 | export CLASSPATH=$CLASSBASE | |
140 | else | |
141 | export CLASSPATH=$CLASSBASE:$CLASSPATH | |
142 | fi | |
143 | fi | |
144 | ||
145 | shift | |
146 | /usr/bin/java $FQCLASS "$@" | |
147 | ====================== Cut here =================== | |
148 | ||
149 | ||
150 | ====================== Cut here =================== | |
151 | /* javaclassname.c | |
152 | * | |
153 | * Extracts the class name from a Java class file; intended for use in a Java | |
154 | * wrapper of the type supported by the binfmt_misc option in the Linux kernel. | |
155 | * | |
156 | * Copyright (C) 1999 Colin J. Watson <cjw44@cam.ac.uk>. | |
157 | * | |
158 | * This program is free software; you can redistribute it and/or modify | |
159 | * it under the terms of the GNU General Public License as published by | |
160 | * the Free Software Foundation; either version 2 of the License, or | |
161 | * (at your option) any later version. | |
162 | * | |
163 | * This program is distributed in the hope that it will be useful, | |
164 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
165 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
166 | * GNU General Public License for more details. | |
167 | * | |
168 | * You should have received a copy of the GNU General Public License | |
169 | * along with this program; if not, write to the Free Software | |
170 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
171 | */ | |
172 | ||
173 | #include <stdlib.h> | |
174 | #include <stdio.h> | |
175 | #include <stdarg.h> | |
176 | #include <sys/types.h> | |
177 | ||
178 | /* From Sun's Java VM Specification, as tag entries in the constant pool. */ | |
179 | ||
180 | #define CP_UTF8 1 | |
181 | #define CP_INTEGER 3 | |
182 | #define CP_FLOAT 4 | |
183 | #define CP_LONG 5 | |
184 | #define CP_DOUBLE 6 | |
185 | #define CP_CLASS 7 | |
186 | #define CP_STRING 8 | |
187 | #define CP_FIELDREF 9 | |
188 | #define CP_METHODREF 10 | |
189 | #define CP_INTERFACEMETHODREF 11 | |
190 | #define CP_NAMEANDTYPE 12 | |
191 | #define CP_METHODHANDLE 15 | |
192 | #define CP_METHODTYPE 16 | |
193 | #define CP_INVOKEDYNAMIC 18 | |
194 | ||
195 | /* Define some commonly used error messages */ | |
196 | ||
197 | #define seek_error() error("%s: Cannot seek\n", program) | |
198 | #define corrupt_error() error("%s: Class file corrupt\n", program) | |
199 | #define eof_error() error("%s: Unexpected end of file\n", program) | |
200 | #define utf8_error() error("%s: Only ASCII 1-255 supported\n", program); | |
201 | ||
202 | char *program; | |
203 | ||
204 | long *pool; | |
205 | ||
206 | u_int8_t read_8(FILE *classfile); | |
207 | u_int16_t read_16(FILE *classfile); | |
208 | void skip_constant(FILE *classfile, u_int16_t *cur); | |
209 | void error(const char *format, ...); | |
210 | int main(int argc, char **argv); | |
211 | ||
212 | /* Reads in an unsigned 8-bit integer. */ | |
213 | u_int8_t read_8(FILE *classfile) | |
214 | { | |
215 | int b = fgetc(classfile); | |
216 | if(b == EOF) | |
217 | eof_error(); | |
218 | return (u_int8_t)b; | |
219 | } | |
220 | ||
221 | /* Reads in an unsigned 16-bit integer. */ | |
222 | u_int16_t read_16(FILE *classfile) | |
223 | { | |
224 | int b1, b2; | |
225 | b1 = fgetc(classfile); | |
226 | if(b1 == EOF) | |
227 | eof_error(); | |
228 | b2 = fgetc(classfile); | |
229 | if(b2 == EOF) | |
230 | eof_error(); | |
231 | return (u_int16_t)((b1 << 8) | b2); | |
232 | } | |
233 | ||
234 | /* Reads in a value from the constant pool. */ | |
235 | void skip_constant(FILE *classfile, u_int16_t *cur) | |
236 | { | |
237 | u_int16_t len; | |
238 | int seekerr = 1; | |
239 | pool[*cur] = ftell(classfile); | |
240 | switch(read_8(classfile)) | |
241 | { | |
242 | case CP_UTF8: | |
243 | len = read_16(classfile); | |
244 | seekerr = fseek(classfile, len, SEEK_CUR); | |
245 | break; | |
246 | case CP_CLASS: | |
247 | case CP_STRING: | |
248 | case CP_METHODTYPE: | |
249 | seekerr = fseek(classfile, 2, SEEK_CUR); | |
250 | break; | |
251 | case CP_METHODHANDLE: | |
252 | seekerr = fseek(classfile, 3, SEEK_CUR); | |
253 | break; | |
254 | case CP_INTEGER: | |
255 | case CP_FLOAT: | |
256 | case CP_FIELDREF: | |
257 | case CP_METHODREF: | |
258 | case CP_INTERFACEMETHODREF: | |
259 | case CP_NAMEANDTYPE: | |
260 | case CP_INVOKEDYNAMIC: | |
261 | seekerr = fseek(classfile, 4, SEEK_CUR); | |
262 | break; | |
263 | case CP_LONG: | |
264 | case CP_DOUBLE: | |
265 | seekerr = fseek(classfile, 8, SEEK_CUR); | |
266 | ++(*cur); | |
267 | break; | |
268 | default: | |
269 | corrupt_error(); | |
270 | } | |
271 | if(seekerr) | |
272 | seek_error(); | |
273 | } | |
274 | ||
275 | void error(const char *format, ...) | |
276 | { | |
277 | va_list ap; | |
278 | va_start(ap, format); | |
279 | vfprintf(stderr, format, ap); | |
280 | va_end(ap); | |
281 | exit(1); | |
282 | } | |
283 | ||
284 | int main(int argc, char **argv) | |
285 | { | |
286 | FILE *classfile; | |
287 | u_int16_t cp_count, i, this_class, classinfo_ptr; | |
288 | u_int8_t length; | |
289 | ||
290 | program = argv[0]; | |
291 | ||
292 | if(!argv[1]) | |
293 | error("%s: Missing input file\n", program); | |
294 | classfile = fopen(argv[1], "rb"); | |
295 | if(!classfile) | |
296 | error("%s: Error opening %s\n", program, argv[1]); | |
297 | ||
298 | if(fseek(classfile, 8, SEEK_SET)) /* skip magic and version numbers */ | |
299 | seek_error(); | |
300 | cp_count = read_16(classfile); | |
301 | pool = calloc(cp_count, sizeof(long)); | |
302 | if(!pool) | |
303 | error("%s: Out of memory for constant pool\n", program); | |
304 | ||
305 | for(i = 1; i < cp_count; ++i) | |
306 | skip_constant(classfile, &i); | |
307 | if(fseek(classfile, 2, SEEK_CUR)) /* skip access flags */ | |
308 | seek_error(); | |
309 | ||
310 | this_class = read_16(classfile); | |
311 | if(this_class < 1 || this_class >= cp_count) | |
312 | corrupt_error(); | |
313 | if(!pool[this_class] || pool[this_class] == -1) | |
314 | corrupt_error(); | |
315 | if(fseek(classfile, pool[this_class] + 1, SEEK_SET)) | |
316 | seek_error(); | |
317 | ||
318 | classinfo_ptr = read_16(classfile); | |
319 | if(classinfo_ptr < 1 || classinfo_ptr >= cp_count) | |
320 | corrupt_error(); | |
321 | if(!pool[classinfo_ptr] || pool[classinfo_ptr] == -1) | |
322 | corrupt_error(); | |
323 | if(fseek(classfile, pool[classinfo_ptr] + 1, SEEK_SET)) | |
324 | seek_error(); | |
325 | ||
326 | length = read_16(classfile); | |
327 | for(i = 0; i < length; ++i) | |
328 | { | |
329 | u_int8_t x = read_8(classfile); | |
330 | if((x & 0x80) || !x) | |
331 | { | |
332 | if((x & 0xE0) == 0xC0) | |
333 | { | |
334 | u_int8_t y = read_8(classfile); | |
335 | if((y & 0xC0) == 0x80) | |
336 | { | |
337 | int c = ((x & 0x1f) << 6) + (y & 0x3f); | |
338 | if(c) putchar(c); | |
339 | else utf8_error(); | |
340 | } | |
341 | else utf8_error(); | |
342 | } | |
343 | else utf8_error(); | |
344 | } | |
345 | else if(x == '/') putchar('.'); | |
346 | else putchar(x); | |
347 | } | |
348 | putchar('\n'); | |
349 | free(pool); | |
350 | fclose(classfile); | |
351 | return 0; | |
352 | } | |
353 | ====================== Cut here =================== | |
354 | ||
355 | ||
356 | ====================== Cut here =================== | |
357 | #!/bin/bash | |
358 | # /usr/local/java/bin/jarwrapper - the wrapper for binfmt_misc/jar | |
359 | ||
360 | java -jar $1 | |
361 | ====================== Cut here =================== | |
362 | ||
363 | ||
364 | Now simply chmod +x the .class, .jar and/or .html files you want to execute. | |
365 | To add a Java program to your path best put a symbolic link to the main | |
366 | .class file into /usr/bin (or another place you like) omitting the .class | |
367 | extension. The directory containing the original .class file will be | |
368 | added to your CLASSPATH during execution. | |
369 | ||
370 | ||
371 | To test your new setup, enter in the following simple Java app, and name | |
372 | it "HelloWorld.java": | |
373 | ||
374 | class HelloWorld { | |
375 | public static void main(String args[]) { | |
376 | System.out.println("Hello World!"); | |
377 | } | |
378 | } | |
379 | ||
380 | Now compile the application with: | |
381 | javac HelloWorld.java | |
382 | ||
383 | Set the executable permissions of the binary file, with: | |
384 | chmod 755 HelloWorld.class | |
385 | ||
386 | And then execute it: | |
387 | ./HelloWorld.class | |
388 | ||
389 | ||
390 | To execute Java Jar files, simple chmod the *.jar files to include | |
391 | the execution bit, then just do | |
392 | ./Application.jar | |
393 | ||
394 | ||
395 | To execute Java Applets, simple chmod the *.html files to include | |
396 | the execution bit, then just do | |
397 | ./Applet.html | |
398 | ||
399 | ||
400 | originally by Brian A. Lantz, brian@lantz.com | |
401 | heavily edited for binfmt_misc by Richard Günther | |
402 | new scripts by Colin J. Watson <cjw44@cam.ac.uk> | |
403 | added executable Jar file support by Kurt Huwig <kurt@iku-netz.de> | |
404 |