usr/src/uts/common/exec/java/java.c

   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, 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, 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[0] = jexec;
 149         idata.intp_arg[0] = jexec_arg;
 150         if (error = pn_get(idata.intp_name[0], 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) fop_close(vp, FREAD, 1, 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 }