xref: /titanic_41/usr/src/uts/common/exec/java/java.c (revision 6357b7bb1039bed3ca23c5942e250f1bf1df550f)
1  /*
2   * CDDL HEADER START
3   *
4   * The contents of this file are subject to the terms of the
5   * Common Development and Distribution License (the "License").
6   * You may not use this file except in compliance with the License.
7   *
8   * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9   * or http://www.opensolaris.org/os/licensing.
10   * See the License for the specific language governing permissions
11   * and limitations under the License.
12   *
13   * When distributing Covered Code, include this CDDL HEADER in each
14   * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15   * If applicable, add the following below this CDDL HEADER, with the
16   * fields enclosed by brackets "[]" replaced with your own identifying
17   * information: Portions Copyright [yyyy] [name of copyright owner]
18   *
19   * CDDL HEADER END
20   */
21  /*
22   * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
23   * Use is subject to license terms.
24   */
25  
26  /*
27   * Launch Java executables via exec(2).
28   *
29   * Java executables are platform-independent executable files
30   * based on the JAR file format.  Executable JAR files contain a
31   * special 'extra field' header in the first file of the archive
32   * that marks the file as a true executable.   The data in that field
33   * is used to pass additional run-time information to the Java VM.
34   *
35   * This handler looks for the appropriate magic number on the
36   * front of the file, checks that the JAR file is executable, then
37   * invokes the Java runtime environment to do the rest of the work.
38   */
39  
40  #include <sys/types.h>
41  #include <sys/proc.h>
42  #include <sys/vnode.h>
43  #include <sys/exec.h>
44  #include <sys/modctl.h>
45  #include <sys/cmn_err.h>
46  #include <sys/pathname.h>
47  
48  /*
49   * These variables can be tweaked via /etc/system to allow prototyping
50   * and debugging.  See PSARC/1997/123.
51   *
52   * Modified by PSARC/1999/012 to be Contract Private between Solaris and
53   * the Java Technology Group.  It is expected that any future change to
54   * these variables be coordinated between the consolidations.
55   */
56  #if defined(__sparc)
57  char *jexec = "/usr/java/jre/lib/sparc/jexec";
58  #elif defined(__i386) || defined(__i386_COMPAT)
59  char *jexec = "/usr/java/jre/lib/i386/jexec";
60  #else
61  #error "Unknown ISA"
62  #endif
63  char *jexec_arg = "-jar";
64  
65  /*
66   * ZIP/JAR file header information
67   */
68  #define	SIGSIZ		4
69  #define	LOCSIG		"PK\003\004"
70  #define	LOCHDRSIZ	30
71  
72  #define	CH(b, n)	(((unsigned char *)(b))[n])
73  #define	SH(b, n)	(CH(b, n) | (CH(b, n+1) << 8))
74  #define	LG(b, n)	(SH(b, n) | (SH(b, n+2) << 16))
75  
76  #define	LOCNAM(b)	(SH(b, 26))	/* filename size */
77  #define	LOCEXT(b)	(SH(b, 28))	/* extra field size */
78  
79  #define	XFHSIZ		4		/* header id, data size */
80  #define	XFHID(b)	(SH(b, 0))	/* extract field header id */
81  #define	XFDATASIZ(b)	(SH(b, 2))	/* extract field data size */
82  #define	XFJAVASIG	0xcafe		/* java executables */
83  
84  /*ARGSUSED3*/
85  static int
86  javaexec(vnode_t *vp, struct execa *uap, struct uarg *args,
87      struct intpdata *idatap, int level, long *execsz, int setid,
88      caddr_t execfile, cred_t *cred, int brand_action)
89  {
90  	struct intpdata idata;
91  	int error;
92  	ssize_t resid;
93  	vnode_t *nvp;
94  	off_t xoff, xoff_end;
95  	char lochdr[LOCHDRSIZ];
96  	struct pathname lookpn;
97  	struct pathname resolvepn;
98  	char *opath;
99  
100  	if (level)
101  		return (ENOEXEC);	/* no recursion */
102  
103  	/*
104  	 * Read in the full local file header, and validate
105  	 * the initial signature.
106  	 */
107  	if ((error = vn_rdwr(UIO_READ, vp, lochdr, sizeof (lochdr),
108  	    0, UIO_SYSSPACE, 0, (rlim64_t)0, cred, &resid)) != 0)
109  		return (error);
110  	if (resid != 0 || strncmp(lochdr, LOCSIG, SIGSIZ) != 0)
111  		return (ENOEXEC);
112  
113  	/*
114  	 * Ok, so this -is- a ZIP file, and might even be a JAR file.
115  	 * Is it a Java executable?
116  	 */
117  	xoff = sizeof (lochdr) + LOCNAM(lochdr);
118  	xoff_end = xoff + LOCEXT(lochdr);
119  
120  	while (xoff < xoff_end) {
121  		char xfhdr[XFHSIZ];
122  
123  		if ((error = vn_rdwr(UIO_READ, vp, xfhdr, sizeof (xfhdr),
124  		    xoff, UIO_SYSSPACE, 0, (rlim64_t)0, cred, &resid)) != 0)
125  			return (error);
126  		if (resid != 0)
127  			return (ENOEXEC);
128  		if (XFHID(xfhdr) == XFJAVASIG)
129  			break;
130  		xoff += sizeof (xfhdr) + XFDATASIZ(xfhdr);
131  	}
132  
133  	if (xoff >= xoff_end)
134  		return (ENOEXEC);
135  
136  	/*
137  	 * Note: If we ever make setid execution work, we need to ensure
138  	 * that we use /dev/fd to avoid the classic setuid shell script
139  	 * security hole.
140  	 */
141  	if (setid)
142  		return (EACCES);
143  
144  	/*
145  	 * Find and invoke the Java runtime environment on the file
146  	 */
147  	idata.intp = NULL;
148  	idata.intp_name = jexec;
149  	idata.intp_arg = jexec_arg;
150  	if (error = pn_get(idata.intp_name, UIO_SYSSPACE, &lookpn))
151  		return (error);
152  	pn_alloc(&resolvepn);
153  	if (error = lookuppn(&lookpn, &resolvepn, FOLLOW, NULLVPP, &nvp)) {
154  		pn_free(&resolvepn);
155  		pn_free(&lookpn);
156  		return (ENOEXEC);
157  	}
158  	opath = args->pathname;
159  	args->pathname = resolvepn.pn_path;
160  	/* don't free resolvepn until we are done with args */
161  	pn_free(&lookpn);
162  	error = gexec(&nvp, uap, args, &idata, level + 1, execsz, execfile,
163  	    cred, EBA_NONE);
164  
165  	if (!error) {
166  		/*
167  		 * Close this Java executable as the interpreter
168  		 * will open and close it later on.
169  		 */
170  		(void) VOP_CLOSE(vp, FREAD, 1, (offset_t)0, cred, NULL);
171  	}
172  
173  	VN_RELE(nvp);
174  	args->pathname = opath;
175  	pn_free(&resolvepn);
176  	return (error);
177  }
178  
179  static struct execsw jexecsw = {
180  	javamagicstr,
181  	0,
182  	4,
183  	javaexec,
184  	NULL
185  };
186  
187  static struct modlexec jmodlexec = {
188  	&mod_execops, "exec for Java", &jexecsw
189  };
190  
191  static struct modlinkage jmodlinkage = {
192  	MODREV_1, &jmodlexec, NULL
193  };
194  
195  int
196  _init(void)
197  {
198  	return (mod_install(&jmodlinkage));
199  }
200  
201  int
202  _fini(void)
203  {
204  	return (mod_remove(&jmodlinkage));
205  }
206  
207  int
208  _info(struct modinfo *modinfop)
209  {
210  	return (mod_info(&jmodlinkage, modinfop));
211  }
212