lib/csu/common_aout/common.c

   1 /*      $NetBSD: common.c,v 1.19 2004/08/07 21:33:04 chs Exp $  */
   2
   3 /*-
   4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Paul Kranenburg.
   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 #ifdef DYNAMIC
  33
  34 typedef int (*rtld_entry_fn) __P((int, struct crt_ldso *));
  35 static struct ld_entry  **ld_entry;
  36
  37 static void
  38 __load_rtld(dp)
  39         struct _dynamic *dp;
  40 {
  41         static struct crt_ldso  crt;
  42         struct exec     hdr;
  43         rtld_entry_fn   entry;
  44 #if defined(sun) && defined(DUPZFD)
  45         int             dupzfd;
  46 #endif
  47
  48 #ifdef DEBUG
  49         /* Provision for alternate ld.so - security risk! */
  50         if ((crt.crt_ldso = _getenv("LDSO")) == NULL)
  51 #endif
  52                 crt.crt_ldso = LDSO;
  53
  54         crt.crt_ldfd = open(crt.crt_ldso, 0, 0);
  55         if (crt.crt_ldfd == -1) {
  56                 _FATAL("No ld.so\n");
  57         }
  58
  59         /* Read LDSO exec header */
  60         if (read(crt.crt_ldfd, &hdr, sizeof hdr) < sizeof hdr) {
  61                 _FATAL("Failure reading ld.so\n");
  62         }
  63         if (N_GETMAGIC(hdr) != ZMAGIC && N_GETMAGIC(hdr) != QMAGIC) {
  64                 _FATAL("Bad magic: ld.so\n");
  65         }
  66
  67 #ifdef sun
  68         /* Get bucket of zeroes */
  69         crt.crt_dzfd = open("/dev/zero", 0, 0);
  70         if (crt.crt_dzfd == -1) {
  71                 _FATAL("No /dev/zero\n");
  72         }
  73 #endif
  74 #ifdef __NetBSD__
  75         /* We use MAP_ANON */
  76         crt.crt_dzfd = -1;
  77 #endif
  78
  79 #if defined(sun) && defined(DUPZFD)
  80         if ((dupzfd = dup(crt.crt_dzfd)) < 0) {
  81                 _FATAL("Cannot dup /dev/zero\n");
  82         }
  83 #endif
  84
  85         /* Map in ld.so */
  86         crt.crt_ba = mmap(0, hdr.a_text+hdr.a_data+hdr.a_bss,
  87                         PROT_READ|PROT_EXEC,
  88                         MAP_FILE|MAP_PRIVATE,
  89                         crt.crt_ldfd, N_TXTOFF(hdr));
  90         if (crt.crt_ba == -1) {
  91                 _FATAL("Cannot map ld.so\n");
  92         }
  93
  94 #ifdef __NetBSD__
  95 /* !!!
  96  * This is gross, ld.so is a ZMAGIC a.out, but has `sizeof(hdr)' for
  97  * an entry point and not at PAGSIZ as the N_*ADDR macros assume.
  98  */
  99 #undef N_DATADDR
 100 #undef N_BSSADDR
 101 #define N_DATADDR(x)    ((x).a_text)
 102 #define N_BSSADDR(x)    ((x).a_text + (x).a_data)
 103 #endif
 104
 105         /* Map in data segment of ld.so writable */
 106         if (mmap(crt.crt_ba+N_DATADDR(hdr), hdr.a_data,
 107                         PROT_READ|PROT_WRITE|PROT_EXEC,
 108                         MAP_FILE|MAP_PRIVATE|MAP_FIXED,
 109                         crt.crt_ldfd, N_DATOFF(hdr)) == -1) {
 110                 _FATAL("Cannot map ld.so\n");
 111         }
 112
 113         /* Map bss segment of ld.so zero */
 114         if (hdr.a_bss && mmap(crt.crt_ba+N_BSSADDR(hdr), hdr.a_bss,
 115                         PROT_READ|PROT_WRITE,
 116                         MAP_ANON|MAP_PRIVATE|MAP_FIXED,
 117                         crt.crt_dzfd, 0) == -1) {
 118                 _FATAL("Cannot map ld.so\n");
 119         }
 120
 121         crt.crt_dp = dp;
 122         crt.crt_ep = environ;
 123         crt.crt_bp = (caddr_t)_callmain;
 124         crt.crt_prog = __progname;
 125
 126 #ifdef sun
 127         /* Call Sun's ld.so entry point: version 1, offset crt */
 128         __call(CRT_VERSION_SUN, &crt, crt.crt_ba + sizeof hdr);
 129 #else
 130         ld_entry = &crt.crt_ldentry;
 131         entry = (rtld_entry_fn)(crt.crt_ba + sizeof hdr);
 132         if ((*entry)(CRT_VERSION_BSD_4, &crt) == -1) {
 133                 /* Feeble attempt to deal with out-dated ld.so */
 134 #ifdef __STDC__
 135 #               define str "crt0: update " LDSO "\n"
 136 #else
 137 #               define str "crt0: update ld.so\n"
 138 #endif
 139                 (void)write(2, str, sizeof(str)-1);
 140 #               undef str
 141                 if ((*entry)(CRT_VERSION_BSD_3, &crt) == -1) {
 142                         _FATAL("ld.so failed\n");
 143                 }
 144                 ld_entry = &dp->d_entry;
 145                 return;
 146         }
 147         atexit((*ld_entry)->dlexit);
 148 #endif
 149
 150 #if defined(sun) && defined(DUPZFD)
 151         if (dup2(dupzfd, crt.crt_dzfd) < 0) {
 152                 _FATAL("Cannot dup2 /dev/zero\n");
 153         }
 154         (void)close(dupzfd);
 155 #endif
 156         return;
 157 }
 158
 159 /*
 160  * DL stubs
 161  */
 162
 163 void *
 164 dlopen(name, mode)
 165         const char      *name;
 166         int     mode;
 167 {
 168         if ((*ld_entry) == NULL)
 169                 return NULL;
 170
 171         return ((*ld_entry)->dlopen)(name, mode);
 172 }
 173
 174 int
 175 dlclose(fd)
 176         void    *fd;
 177 {
 178         if ((*ld_entry) == NULL)
 179                 return -1;
 180
 181         return ((*ld_entry)->dlclose)(fd);
 182 }
 183
 184 void *
 185 dlsym(fd, name)
 186         void    *fd;
 187         const char      *name;
 188 {
 189         if ((*ld_entry) == NULL)
 190                 return NULL;
 191
 192         return ((*ld_entry)->dlsym)(fd, name);
 193 }
 194
 195 int
 196 dlctl(fd, cmd, arg)
 197         void    *fd, *arg;
 198         int     cmd;
 199 {
 200         if ((*ld_entry) == NULL)
 201                 return -1;
 202
 203         return ((*ld_entry)->dlctl)(fd, cmd, arg);
 204 }
 205
 206 __aconst char *
 207 dlerror()
 208 {
 209         int     error;
 210
 211         if ((*ld_entry) == NULL ||
 212             (*(*ld_entry)->dlctl)(NULL, DL_GETERRNO, &error) == -1)
 213                 return "Service unavailable";
 214
 215         return ((char *)(error == 0 ? NULL : strerror(error)));
 216 }
 217
 218 int
 219 dladdr(addr, dli)
 220         const void      *addr;
 221         Dl_info *dli;
 222 {
 223         if ((*ld_entry) == NULL || (*ld_entry)->dladdr == NULL)
 224                 return (0);
 225
 226         return ((*ld_entry)->dladdr)(addr, dli);
 227 }
 228
 229 /*
 230  * Support routines
 231  */
 232
 233 #ifdef DEBUG
 234 static int
 235 _strncmp(s1, s2, n)
 236         char *s1, *s2;
 237         int n;
 238 {
 239
 240         if (n == 0)
 241                 return (0);
 242         do {
 243                 if (*s1 != *s2++)
 244                         return (*(unsigned char *)s1 - *(unsigned char *)--s2);
 245                 if (*s1++ == 0)
 246                         break;
 247         } while (--n != 0);
 248         return (0);
 249 }
 250
 251 static char *
 252 _getenv(name)
 253         char *name;
 254 {
 255         extern char **environ;
 256         int len;
 257         char **P, *C;
 258
 259         for (C = name, len = 0; *C && *C != '='; ++C, ++len);
 260         for (P = environ; *P; ++P)
 261                 if (!_strncmp(*P, name, len))
 262                         if (*(C = *P + len) == '=') {
 263                                 return(++C);
 264                         }
 265         return (char *)0;
 266 }
 267 #endif
 268
 269 static char *
 270 _strrchr(p, ch)
 271 char *p, ch;
 272 {
 273         char *save;
 274
 275         for (save = NULL;; ++p) {
 276                 if (*p == ch)
 277                         save = (char *)p;
 278                 if (!*p)
 279                         return(save);
 280         }
 281 /* NOTREACHED */
 282 }
 283
 284 #endif /* DYNAMIC */