xref: /illumos-gate/usr/src/uts/common/exec/java/java.c (revision 4fd09333)
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(__x86)
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
javaexec(vnode_t * vp,struct execa * uap,struct uarg * args,struct intpdata * idatap,int level,long * execsz,int setid,caddr_t execfile,cred_t * cred,int brand_action)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 	bzero(&idata, sizeof (intpdata_t));
148 	idata.intp = NULL;
149 	idata.intp_name[0] = jexec;
150 	idata.intp_arg[0] = jexec_arg;
151 	if (error = pn_get(idata.intp_name[0], UIO_SYSSPACE, &lookpn))
152 		return (error);
153 	pn_alloc(&resolvepn);
154 	if (error = lookuppn(&lookpn, &resolvepn, FOLLOW, NULLVPP, &nvp)) {
155 		pn_free(&resolvepn);
156 		pn_free(&lookpn);
157 		return (ENOEXEC);
158 	}
159 	opath = args->pathname;
160 	args->pathname = resolvepn.pn_path;
161 	/* don't free resolvepn until we are done with args */
162 	pn_free(&lookpn);
163 	error = gexec(&nvp, uap, args, &idata, level + 1, execsz, execfile,
164 	    cred, EBA_NONE);
165 
166 	if (!error) {
167 		/*
168 		 * Close this Java executable as the interpreter
169 		 * will open and close it later on.
170 		 */
171 		(void) VOP_CLOSE(vp, FREAD, 1, (offset_t)0, cred, NULL);
172 	}
173 
174 	VN_RELE(nvp);
175 	args->pathname = opath;
176 	pn_free(&resolvepn);
177 	return (error);
178 }
179 
180 static struct execsw jexecsw = {
181 	javamagicstr,
182 	0,
183 	4,
184 	javaexec,
185 	NULL
186 };
187 
188 static struct modlexec jmodlexec = {
189 	&mod_execops, "exec for Java", &jexecsw
190 };
191 
192 static struct modlinkage jmodlinkage = {
193 	MODREV_1, &jmodlexec, NULL
194 };
195 
196 int
_init(void)197 _init(void)
198 {
199 	return (mod_install(&jmodlinkage));
200 }
201 
202 int
_fini(void)203 _fini(void)
204 {
205 	return (mod_remove(&jmodlinkage));
206 }
207 
208 int
_info(struct modinfo * modinfop)209 _info(struct modinfo *modinfop)
210 {
211 	return (mod_info(&jmodlinkage, modinfop));
212 }
213