usr/src/cmd/mdb/common/kmdb/kmdb_dl.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 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include <dlfcn.h>
  30 #include <sys/modctl.h>
  31 #include <sys/kobj.h>
  32
  33 #include <kmdb/kmdb_module.h>
  34 #include <mdb/mdb_debug.h>
  35 #include <mdb/mdb_gelf.h>
  36 #include <mdb/mdb_string.h>
  37 #include <mdb/mdb.h>
  38
  39 /*
  40  * kmdb libdl-style interface for the manipulation of dmods.
  41  */
  42
  43 static char *dl_errstr;
  44
  45 static kmdb_modctl_t *
  46 dl_name2ctl(const char *pathname)
  47 {
  48         mdb_var_t *v;
  49
  50         if ((v = mdb_nv_lookup(&mdb.m_dmodctl, strbasename(pathname))) ==
  51             NULL)
  52                 return (NULL);
  53
  54         return ((kmdb_modctl_t *)MDB_NV_COOKIE(v));
  55 }
  56
  57 /*ARGSUSED*/
  58 void *
  59 dlmopen(Lmid_t lmid, const char *pathname, int mode)
  60 {
  61         kmdb_modctl_t *kmc;
  62
  63         if ((kmc = dl_name2ctl(pathname)) == NULL) {
  64                 dl_errstr = "unregistered module";
  65                 return (NULL);
  66         }
  67
  68         kmc->kmc_dlrefcnt++;
  69
  70         dl_errstr = NULL;
  71
  72         return (kmc);
  73 }
  74
  75 int
  76 dlclose(void *dlp)
  77 {
  78         kmdb_modctl_t *kmc = dlp;
  79
  80         dl_errstr = NULL;
  81
  82         ASSERT(kmc->kmc_dlrefcnt > 0);
  83         if (--kmc->kmc_dlrefcnt > 0)
  84                 return (0);
  85
  86         return (0);
  87 }
  88
  89 char *
  90 dlerror(void)
  91 {
  92         char *str = dl_errstr;
  93
  94         dl_errstr = NULL;
  95
  96         return (str);
  97 }
  98
  99 static void *
 100 dl_findsym(kmdb_modctl_t *kmc, const char *name)
 101 {
 102         GElf_Sym sym;
 103         uint_t symid;
 104
 105         if (mdb_gelf_symtab_lookup_by_name(kmc->kmc_symtab, name, &sym,
 106             &symid) < 0)
 107                 return (NULL);
 108
 109         return ((void *)(uintptr_t)sym.st_value);
 110 }
 111
 112 /*ARGSUSED*/
 113 void *
 114 dlsym(void *dlp, const char *name)
 115 {
 116         kmdb_modctl_t *kmc = dlp;
 117         mdb_var_t *v;
 118         void *addr;
 119
 120         switch ((uintptr_t)dlp) {
 121         case (uintptr_t)RTLD_NEXT:
 122                 mdb_nv_rewind(&mdb.m_dmodctl);
 123                 while ((v = mdb_nv_advance(&mdb.m_dmodctl)) != NULL) {
 124                         if ((addr = dl_findsym(MDB_NV_COOKIE(v), name)) != NULL)
 125                                 break;
 126                 }
 127                 break;
 128
 129         case (uintptr_t)RTLD_DEFAULT:
 130         case (uintptr_t)RTLD_SELF:
 131                 dl_errstr = "invalid handle";
 132                 return (NULL);
 133
 134         default:
 135                 addr = dl_findsym(kmc, name);
 136         }
 137
 138         dl_errstr = (addr == NULL) ? "symbol not found" : NULL;
 139
 140         return (addr);
 141 }
 142
 143 #pragma weak _dladdr1 = dladdr1
 144 /*ARGSUSED*/
 145 int
 146 dladdr1(void *address, Dl_info *dlip, void **info, int flags)
 147 {
 148         /*
 149          * umem uses this for debugging information.  We'll pretend to fail.
 150          */
 151
 152         return (0);
 153 }