usr/src/cmd/mdb/common/modules/libumem/misc.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 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #include "misc.h"
  27
  28 #define UMEM_OBJNAME "libumem.so.1"
  29
  30 int umem_debug_level = 0;
  31 int umem_is_standalone = 0;
  32
  33 /*ARGSUSED*/
  34 int
  35 umem_debug(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
  36 {
  37         umem_debug_level ^= 1;
  38
  39         mdb_printf("umem: debugging is now %s\n",
  40             umem_debug_level ? "on" : "off");
  41
  42         return (DCMD_OK);
  43 }
  44
  45 /*
  46  * To further confuse the issue, this dmod can run against either
  47  * libumem.so.1 *or* the libstandumem.so linked into kmdb(1M).  To figure
  48  * out which one we are working against, we look up "umem_alloc" in both
  49  * libumem.so and the executable.
  50  *
  51  * A further wrinkle is that libumem.so may not yet be loaded into the
  52  * process' address space.  That can lead to either the lookup failing, or
  53  * being unable to read from the data segment.  We treat either case as
  54  * an error.
  55  */
  56 int
  57 umem_set_standalone(void)
  58 {
  59         GElf_Sym sym;
  60         int ready;
  61
  62         if (mdb_lookup_by_obj(UMEM_OBJNAME, "umem_alloc", &sym) == 0)
  63                 umem_is_standalone = 0;
  64         else if (mdb_lookup_by_obj(MDB_OBJ_EXEC, "umem_alloc", &sym) == 0)
  65                 umem_is_standalone = 1;
  66         else
  67                 return (-1);
  68
  69         /*
  70          * now that we know where things should be, make sure we can actually
  71          * read things out.
  72          */
  73         if (umem_readvar(&ready, "umem_ready") == -1)
  74                 return (-1);
  75         return (0);
  76 }
  77
  78 ssize_t
  79 umem_lookup_by_name(const char *name, GElf_Sym *sym)
  80 {
  81         return (mdb_lookup_by_obj((umem_is_standalone ? MDB_OBJ_EXEC :
  82             UMEM_OBJNAME), name, sym));
  83 }
  84
  85 /* This is like mdb_readvar, only for libumem.so's symbols */
  86 ssize_t
  87 umem_readvar(void *buf, const char *name)
  88 {
  89         GElf_Sym sym;
  90
  91         if (umem_lookup_by_name(name, &sym))
  92                 return (-1);
  93
  94         if (mdb_vread(buf, sym.st_size, (uintptr_t)sym.st_value)
  95             == sym.st_size)
  96                 return ((ssize_t)sym.st_size);
  97
  98         return (-1);
  99 }
 100
 101 int
 102 is_umem_sym(const char *sym, const char *prefix)
 103 {
 104         char *tick_p = strrchr(sym, '`');
 105
 106         return (strncmp(sym, "libumem", 7) == 0 && tick_p != NULL &&
 107             strncmp(tick_p + 1, prefix, strlen(prefix)) == 0);
 108 }