sys/compat/linux/common/linux_uselib.c

   1 /*      $NetBSD: linux_uselib.c,v 1.29 2009/08/15 23:39:35 matt Exp $   */
   2
   3 /*-
   4  * Copyright (c) 1995, 1998 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, Frank van der Linden and Eric Haszlakiewicz.
   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 #include <sys/cdefs.h>
  33 __KERNEL_RCSID(0, "$NetBSD: linux_uselib.c,v 1.29 2009/08/15 23:39:35 matt Exp $");
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/kernel.h>
  38 #include <sys/proc.h>
  39 #include <sys/malloc.h>
  40 #include <sys/namei.h>
  41 #include <sys/vnode.h>
  42 #include <sys/mount.h>
  43 #include <sys/exec.h>
  44 #include <sys/exec_aout.h>
  45
  46 #include <sys/mman.h>
  47 #include <sys/syscallargs.h>
  48
  49 #include <sys/cpu.h>
  50 #include <machine/reg.h>
  51
  52 #include <compat/linux/common/linux_types.h>
  53 #include <compat/linux/common/linux_signal.h>
  54 #include <compat/linux/common/linux_util.h>
  55 #include <compat/linux/common/linux_exec.h>
  56 #include <compat/linux/common/linux_machdep.h>
  57 #include <compat/linux/common/linux_ipc.h>
  58 #include <compat/linux/common/linux_sem.h>
  59
  60 #ifndef EXEC_AOUT
  61 /* define EXEC_AOUT to get prototype from linux_syscall.h */
  62 #define EXEC_AOUT
  63 #endif
  64
  65 #include <compat/linux/linux_syscallargs.h>
  66 #include <compat/linux/linux_syscall.h>
  67
  68 /*
  69  * The Linux system call to load shared libraries, a.out version. The
  70  * a.out shared libs are just files that are mapped onto a fixed
  71  * address in the process' address space. The address is given in
  72  * a_entry. Read in the header, set up some VM commands and run them.
  73  *
  74  * Yes, both text and data are mapped at once, so we're left with
  75  * writable text for the shared libs. The Linux crt0 seemed to break
  76  * sometimes when data was mapped separately. It munmapped a uselib()
  77  * of ld.so by hand, which failed with shared text and data for ld.so
  78  * Yuck.
  79  *
  80  * Because of the problem with ZMAGIC executables (text starts
  81  * at 0x400 in the file, but needs to be mapped at 0), ZMAGIC
  82  * shared libs are not handled very efficiently :-(
  83  */
  84
  85 int
  86 linux_sys_uselib(struct lwp *l, const struct linux_sys_uselib_args *uap, register_t *retval)
  87 {
  88         /* {
  89                 syscallarg(const char *) path;
  90         } */
  91         long bsize, dsize, tsize, taddr, baddr, daddr;
  92         struct vnode *vp;
  93         struct exec hdr;
  94         struct exec_vmcmd_set vcset;
  95         int i, magic, error;
  96         size_t rem;
  97
  98         error = namei_simple_user(SCARG(uap, path),
  99                                 NSM_FOLLOW_TRYEMULROOT, &vp);
 100         if (error != 0)
 101                 return error;
 102
 103         if ((error = vn_rdwr(UIO_READ, vp, (void *) &hdr, LINUX_AOUT_HDR_SIZE,
 104                              0, UIO_SYSSPACE, IO_NODELOCKED, l->l_cred,
 105                              &rem, NULL))) {
 106                 vrele(vp);
 107                 return error;
 108         }
 109
 110         if (rem != 0) {
 111                 vrele(vp);
 112                 return ENOEXEC;
 113         }
 114
 115         if (LINUX_N_MACHTYPE(&hdr) != LINUX_MID_MACHINE)
 116                 return ENOEXEC;
 117
 118         magic = LINUX_N_MAGIC(&hdr);
 119         taddr = hdr.a_entry & (~(PAGE_SIZE - 1));
 120         tsize = hdr.a_text;
 121         daddr = taddr + tsize;
 122         dsize = hdr.a_data + hdr.a_bss;
 123
 124         error = vn_marktext(vp);
 125         if (error)
 126                 return (error);
 127
 128         vcset.evs_cnt = 0;
 129         vcset.evs_used = 0;
 130
 131         NEW_VMCMD(&vcset,
 132                   magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn,
 133                   hdr.a_text + hdr.a_data, taddr,
 134                   vp, LINUX_N_TXTOFF(hdr, magic),
 135                   VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE);
 136
 137         baddr = roundup(daddr + hdr.a_data, PAGE_SIZE);
 138         bsize = daddr + dsize - baddr;
 139         if (bsize > 0) {
 140                 NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr,
 141                     NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
 142         }
 143
 144         for (i = 0; i < vcset.evs_used && !error; i++) {
 145                 struct exec_vmcmd *vcp;
 146
 147                 vcp = &vcset.evs_cmds[i];
 148                 error = (*vcp->ev_proc)(l, vcp);
 149         }
 150
 151         kill_vmcmds(&vcset);
 152
 153         vrele(vp);
 154
 155         return error;
 156 }