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compat_util.c revision 1.43.4.1
      1 /* 	$NetBSD: compat_util.c,v 1.43.4.1 2011/03/05 20:52:38 rmind Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1994 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas and Frank van der Linden.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * Copyright (c) 2008, 2009 Matthew R. Green
     34  * All rights reserved.
     35  *
     36  * Redistribution and use in source and binary forms, with or without
     37  * modification, are permitted provided that the following conditions
     38  * are met:
     39  * 1. Redistributions of source code must retain the above copyright
     40  *    notice, this list of conditions and the following disclaimer.
     41  * 2. Redistributions in binary form must reproduce the above copyright
     42  *    notice, this list of conditions and the following disclaimer in the
     43  *    documentation and/or other materials provided with the distribution.
     44  * 3. The name of the author may not be used to endorse or promote products
     45  *    derived from this software without specific prior written permission.
     46  *
     47  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     48  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     49  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     50  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     51  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     52  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     53  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     54  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     55  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     57  * SUCH DAMAGE.
     58  */
     59 
     60 #include <sys/cdefs.h>
     61 __KERNEL_RCSID(0, "$NetBSD: compat_util.c,v 1.43.4.1 2011/03/05 20:52:38 rmind Exp $");
     62 
     63 #include <sys/param.h>
     64 #include <sys/systm.h>
     65 #include <sys/namei.h>
     66 #include <sys/proc.h>
     67 #include <sys/file.h>
     68 #include <sys/stat.h>
     69 #include <sys/filedesc.h>
     70 #include <sys/exec.h>
     71 #include <sys/ioctl.h>
     72 #include <sys/kernel.h>
     73 #include <sys/malloc.h>
     74 #include <sys/vnode.h>
     75 #include <sys/syslog.h>
     76 #include <sys/mount.h>
     77 
     78 #include <compat/common/compat_util.h>
     79 
     80 void
     81 emul_find_root(struct lwp *l, struct exec_package *epp)
     82 {
     83 	struct vnode *vp;
     84 	const char *emul_path;
     85 
     86 	if (epp->ep_emul_root != NULL)
     87 		/* We've already found it */
     88 		return;
     89 
     90 	emul_path = epp->ep_esch->es_emul->e_path;
     91 	if (emul_path == NULL)
     92 		/* Emulation doesn't have a root */
     93 		return;
     94 
     95 	if (namei_simple_kernel(emul_path, NSM_FOLLOW_NOEMULROOT, &vp) != 0)
     96 		/* emulation root doesn't exist */
     97 		return;
     98 
     99 	epp->ep_emul_root = vp;
    100 }
    101 
    102 /*
    103  * Search the alternate path for dynamic binary interpreter. If not found
    104  * there, check if the interpreter exists in within 'proper' tree.
    105  */
    106 int
    107 emul_find_interp(struct lwp *l, struct exec_package *epp, const char *itp)
    108 {
    109 	int error;
    110 	struct pathbuf *pb;
    111 	struct nameidata nd;
    112 	unsigned int flags;
    113 
    114 	pb = pathbuf_create(itp);
    115 	if (pb == NULL) {
    116 		return ENOMEM;
    117 	}
    118 
    119 	/* If we haven't found the emulation root already, do so now */
    120 	/* Maybe we should remember failures somehow ? */
    121 	if (epp->ep_esch->es_emul->e_path != 0 && epp->ep_emul_root == NULL)
    122 		emul_find_root(l, epp);
    123 
    124 	if (epp->ep_interp != NULL)
    125 		vrele(epp->ep_interp);
    126 
    127 	/* We need to use the emulation root for the new program,
    128 	 * not the one for the current process. */
    129 	if (epp->ep_emul_root == NULL)
    130 		flags = FOLLOW;
    131 	else {
    132 		nd.ni_erootdir = epp->ep_emul_root;
    133 		/* hack: Pass in the emulation path for ktrace calls */
    134 		nd.ni_next = epp->ep_esch->es_emul->e_path;
    135 		flags = FOLLOW | TRYEMULROOT | EMULROOTSET;
    136 	}
    137 
    138 	NDINIT(&nd, LOOKUP, flags, pb);
    139 	error = namei(&nd);
    140 	if (error != 0) {
    141 		epp->ep_interp = NULL;
    142 		return error;
    143 	}
    144 
    145 	/* Save interpreter in case we actually need to load it */
    146 	epp->ep_interp = nd.ni_vp;
    147 
    148 	pathbuf_destroy(pb);
    149 
    150 	return 0;
    151 }
    152 
    153 /*
    154  * Translate one set of flags to another, based on the entries in
    155  * the given table.  If 'leftover' is specified, it is filled in
    156  * with any flags which could not be translated.
    157  */
    158 unsigned long
    159 emul_flags_translate(const struct emul_flags_xtab *tab,
    160 		     unsigned long in, unsigned long *leftover)
    161 {
    162 	unsigned long out;
    163 
    164 	for (out = 0; tab->omask != 0; tab++) {
    165 		if ((in & tab->omask) == tab->oval) {
    166 			in &= ~tab->omask;
    167 			out |= tab->nval;
    168 		}
    169 	}
    170 	if (leftover != NULL)
    171 		*leftover = in;
    172 	return (out);
    173 }
    174 
    175 void
    176 compat_offseterr(struct vnode *vp, const char *msg)
    177 {
    178 	struct mount *mp;
    179 
    180 	mp = vp->v_mount;
    181 
    182 	log(LOG_ERR, "%s: dir offset too large on fs %s (mounted from %s)\n",
    183 	    msg, mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname);
    184 	uprintf("%s: dir offset too large for emulated program\n", msg);
    185 }
    186 
    187 /*
    188  * Look for native NetBSD compatibility libraries, usually interp-ABI.
    189  * It returns 0 if it changed the interpreter, otherwise it returns
    190  * the error from namei().  Callers should not try any more processing
    191  * if this returns 0, and probably should just ignore the return value.
    192  */
    193 int
    194 compat_elf_check_interp(struct exec_package *epp,
    195 			char *interp,
    196 			const char *interp_suffix)
    197 {
    198 	int error = 0;
    199 
    200 	/*
    201 	 * Don't look for something else, if someone has already found and
    202 	 * setup the ep_interp already.
    203 	 */
    204 	if (interp && epp->ep_interp == NULL) {
    205 		/*
    206 		 * If the path is exactly "/usr/libexec/ld.elf_so", first
    207 		 * try to see if "/usr/libexec/ld.elf_so-<abi>" exists
    208 		 * and if so, use that instead.
    209 		 */
    210 		if (strcmp(interp, "/usr/libexec/ld.elf_so") == 0 ||
    211 		    strcmp(interp, "/libexec/ld.elf_so") == 0) {
    212 			struct vnode *vp;
    213 			char *path;
    214 
    215 			path = PNBUF_GET();
    216 			snprintf(path, MAXPATHLEN, "%s-%s", interp, interp_suffix);
    217 			error = namei_simple_kernel(path,
    218 					NSM_FOLLOW_NOEMULROOT, &vp);
    219 			/*
    220 			 * If that worked, replace interpreter in case we
    221 			 * actually need to load it.
    222 			 */
    223 			if (error == 0) {
    224 				epp->ep_interp = vp;
    225 				snprintf(interp, MAXPATHLEN, "%s", path);
    226 			}
    227 			PNBUF_PUT(path);
    228 		}
    229 	}
    230 	return error;
    231 }
    232