usr/src/cmd/sgs/libld/common/exit.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 (c) 1988 AT&T
  24  *        All Rights Reserved
  25  *
  26  * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
  27  */
  28
  29 /*
  30  * Utility functions
  31  */
  32 #include        <unistd.h>
  33 #include        <signal.h>
  34 #include        <locale.h>
  35 #include        <string.h>
  36 #include        "msg.h"
  37 #include        "_libld.h"
  38
  39 /*
  40  * Exit after cleaning up.
  41  */
  42 int
  43 ld_exit(Ofl_desc *ofl)
  44 {
  45         /*
  46          * If we have created an output file remove it.
  47          */
  48         if ((ofl->ofl_fd > 0) && ((ofl->ofl_flags1 & FLG_OF1_NONREG) == 0))
  49                 (void) unlink(ofl->ofl_name);
  50
  51         /*
  52          * Inform any support library that the link-edit has failed.
  53          */
  54         ld_sup_atexit(ofl, 1);
  55
  56         /*
  57          * Wrap up debug output file if one is open
  58          */
  59         dbg_cleanup();
  60
  61         /* If any ERR_GUIDANCE messages were issued, add a summary */
  62         if (ofl->ofl_guideflags & FLG_OFG_ISSUED)
  63                 ld_eprintf(ofl, ERR_GUIDANCE, MSG_INTL(MSG_GUIDE_SUMMARY));
  64
  65         return (1);
  66 }
  67
  68 /*
  69  * Establish the signals we're interested in, and the handlers that need to be
  70  * reinstalled should any of these signals occur.
  71  */
  72 typedef struct {
  73         int     signo;
  74         void (* defhdl)();
  75 } Signals;
  76
  77 static Signals signals[] = {
  78         { SIGHUP,       SIG_DFL },
  79         { SIGINT,       SIG_IGN },
  80         { SIGQUIT,      SIG_DFL },
  81         { SIGBUS,       SIG_DFL },
  82         { SIGTERM,      SIG_IGN },
  83         { 0,            0 } };
  84
  85 static Ofl_desc *Ofl = NULL;
  86
  87 /*
  88  * Define our signal handler.
  89  */
  90 static void
  91 /* ARGSUSED2 */
  92 handler(int sig, siginfo_t *sip, void *utp)
  93 {
  94         struct sigaction        nact;
  95         Signals *               sigs;
  96
  97         /*
  98          * Reset all ignore handlers regardless of how we got here.
  99          */
 100         nact.sa_handler = SIG_IGN;
 101         nact.sa_flags = 0;
 102         (void) sigemptyset(&nact.sa_mask);
 103
 104         for (sigs = signals; sigs->signo; sigs++) {
 105                 if (sigs->defhdl == SIG_IGN)
 106                         (void) sigaction(sigs->signo, &nact, NULL);
 107         }
 108
 109         /*
 110          * The model for creating an output file is to ftruncate() it to the
 111          * required size and mmap() a mapping into which the new contents are
 112          * written.  Neither of these operations guarantee that the required
 113          * disk blocks exist, and should we run out of disk space a bus error
 114          * is generated.
 115          * Other situations have been reported to result in ld catching a bus
 116          * error (one instance was a stale NFS handle from an unstable server).
 117          * Thus we catch all bus errors and hope we can decode a better error.
 118          */
 119         if ((sig == SIGBUS) && sip && Ofl->ofl_name) {
 120                 ld_eprintf(Ofl, ERR_FATAL, MSG_INTL(MSG_FIL_INTERRUPT),
 121                     Ofl->ofl_name, strerror(sip->si_errno));
 122         }
 123         /*
 124          * This assert(0) causes DEBUG enabled linkers to produce a core file.
 125          */
 126         if ((sig != SIGHUP) && (sig != SIGINT))
 127                 assert(0);
 128
 129         exit(ld_exit(Ofl));
 130 }
 131
 132 /*
 133  * Establish a signal handler for all signals we're interested in.
 134  */
 135 void
 136 ld_init_sighandler(Ofl_desc *ofl)
 137 {
 138         struct sigaction        nact, oact;
 139         Signals *               sigs;
 140
 141         Ofl = ofl;
 142
 143         /*
 144          * Our heavy use of mmap() means that we are susceptible to
 145          * receiving a SIGBUS in low diskspace situations. The main
 146          * purpose of the signal handler is to handle that situation
 147          * gracefully, so that out of disk errors don't drop a core file.
 148          *
 149          * In rare cases, this will prevent us from getting a core from a
 150          * SIGBUS triggered by an internal alignment error in libld.
 151          * If -znosighandler is set, return without registering the
 152          * handler. This is primarily of use for debugging problems in
 153          * the field, and is not of general interest.
 154          */
 155         if (ofl->ofl_flags1 & FLG_OF1_NOSGHND)
 156                 return;
 157
 158         /*
 159          * For each signal we're interested in set up a signal handler that
 160          * insures we clean up any output file we're in the middle of creating.
 161          */
 162         nact.sa_sigaction = handler;
 163         (void) sigemptyset(&nact.sa_mask);
 164
 165         for (sigs = signals; sigs->signo; sigs++) {
 166                 if ((sigaction(sigs->signo, NULL, &oact) == 0) &&
 167                     (oact.sa_handler != SIG_IGN)) {
 168                         nact.sa_flags = SA_SIGINFO;
 169                         if (sigs->defhdl == SIG_DFL)
 170                                 nact.sa_flags |= (SA_RESETHAND | SA_NODEFER);
 171                         (void) sigaction(sigs->signo, &nact, NULL);
 172                 }
 173         }
 174 }