elf/dl-misc.c

   1 /* Miscellaneous support functions for dynamic linker
   2    Copyright (C) 1997-2002, 2003, 2004, 2006 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <assert.h>
  21 #include <fcntl.h>
  22 #include <ldsodefs.h>
  23 #include <limits.h>
  24 #include <link.h>
  25 #include <stdarg.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <sys/mman.h>
  30 #include <sys/param.h>
  31 #include <sys/stat.h>
  32 #include <sys/uio.h>
  33 #include <sysdep.h>
  34 #include <stdio-common/_itoa.h>
  35 #include <bits/libc-lock.h>
  36
  37 #ifndef MAP_ANON
  38 /* This is the only dl-sysdep.c function that is actually needed at run-time
  39    by _dl_map_object.  */
  40
  41 int
  42 _dl_sysdep_open_zero_fill (void)
  43 {
  44   return __open ("/dev/zero", O_RDONLY);
  45 }
  46 #endif
  47
  48 /* Read the whole contents of FILE into new mmap'd space with given
  49    protections.  *SIZEP gets the size of the file.  On error MAP_FAILED
  50    is returned.  */
  51
  52 void *
  53 internal_function
  54 _dl_sysdep_read_whole_file (const char *file, size_t *sizep, int prot)
  55 {
  56   void *result = MAP_FAILED;
  57   struct stat64 st;
  58   int fd = __open (file, O_RDONLY);
  59   if (fd >= 0)
  60     {
  61       if (__fxstat64 (_STAT_VER, fd, &st) >= 0)
  62         {
  63           *sizep = st.st_size;
  64
  65           /* No need to map the file if it is empty.  */
  66           if (*sizep != 0)
  67             /* Map a copy of the file contents.  */
  68             result = __mmap (NULL, *sizep, prot,
  69 #ifdef MAP_COPY
  70                              MAP_COPY
  71 #else
  72                              MAP_PRIVATE
  73 #endif
  74 #ifdef MAP_FILE
  75                              | MAP_FILE
  76 #endif
  77                              , fd, 0);
  78         }
  79       __close (fd);
  80     }
  81   return result;
  82 }
  83
  84
  85 /* Bare-bones printf implementation.  This function only knows about
  86    the formats and flags needed and can handle only up to 64 stripes in
  87    the output.  */
  88 static void
  89 _dl_debug_vdprintf (int fd, int tag_p, const char *fmt, va_list arg)
  90 {
  91 # define NIOVMAX 64
  92   struct iovec iov[NIOVMAX];
  93   int niov = 0;
  94   pid_t pid = 0;
  95   char pidbuf[12];
  96
  97   while (*fmt != '\0')
  98     {
  99       const char *startp = fmt;
 100
 101       if (tag_p > 0)
 102         {
 103           /* Generate the tag line once.  It consists of the PID and a
 104              colon followed by a tab.  */
 105           if (pid == 0)
 106             {
 107               char *p;
 108               pid = __getpid ();
 109               assert (pid >= 0 && sizeof (pid_t) <= 4);
 110               p = _itoa (pid, &pidbuf[10], 10, 0);
 111               while (p > pidbuf)
 112                 *--p = ' ';
 113               pidbuf[10] = ':';
 114               pidbuf[11] = '\t';
 115             }
 116
 117           /* Append to the output.  */
 118           assert (niov < NIOVMAX);
 119           iov[niov].iov_len = 12;
 120           iov[niov++].iov_base = pidbuf;
 121
 122           /* No more tags until we see the next newline.  */
 123           tag_p = -1;
 124         }
 125
 126       /* Skip everything except % and \n (if tags are needed).  */
 127       while (*fmt != '\0' && *fmt != '%' && (! tag_p || *fmt != '\n'))
 128         ++fmt;
 129
 130       /* Append constant string.  */
 131       assert (niov < NIOVMAX);
 132       if ((iov[niov].iov_len = fmt - startp) != 0)
 133         iov[niov++].iov_base = (char *) startp;
 134
 135       if (*fmt == '%')
 136         {
 137           /* It is a format specifier.  */
 138           char fill = ' ';
 139           int width = -1;
 140           int prec = -1;
 141 #if LONG_MAX != INT_MAX
 142           int long_mod = 0;
 143 #endif
 144
 145           /* Recognize zero-digit fill flag.  */
 146           if (*++fmt == '0')
 147             {
 148               fill = '0';
 149               ++fmt;
 150             }
 151
 152           /* See whether with comes from a parameter.  Note that no other
 153              way to specify the width is implemented.  */
 154           if (*fmt == '*')
 155             {
 156               width = va_arg (arg, int);
 157               ++fmt;
 158             }
 159
 160           /* Handle precision.  */
 161           if (*fmt == '.' && fmt[1] == '*')
 162             {
 163               prec = va_arg (arg, int);
 164               fmt += 2;
 165             }
 166
 167           /* Recognize the l modifier.  It is only important on some
 168              platforms where long and int have a different size.  We
 169              can use the same code for size_t.  */
 170           if (*fmt == 'l' || *fmt == 'Z')
 171             {
 172 #if LONG_MAX != INT_MAX
 173               long_mod = 1;
 174 #endif
 175               ++fmt;
 176             }
 177
 178           switch (*fmt)
 179             {
 180               /* Integer formatting.  */
 181             case 'u':
 182             case 'x':
 183               {
 184                 /* We have to make a difference if long and int have a
 185                    different size.  */
 186 #if LONG_MAX != INT_MAX
 187                 unsigned long int num = (long_mod
 188                                          ? va_arg (arg, unsigned long int)
 189                                          : va_arg (arg, unsigned int));
 190 #else
 191                 unsigned long int num = va_arg (arg, unsigned int);
 192 #endif
 193                 /* We use alloca() to allocate the buffer with the most
 194                    pessimistic guess for the size.  Using alloca() allows
 195                    having more than one integer formatting in a call.  */
 196                 char *buf = (char *) alloca (3 * sizeof (unsigned long int));
 197                 char *endp = &buf[3 * sizeof (unsigned long int)];
 198                 char *cp = _itoa (num, endp, *fmt == 'x' ? 16 : 10, 0);
 199
 200                 /* Pad to the width the user specified.  */
 201                 if (width != -1)
 202                   while (endp - cp < width)
 203                     *--cp = fill;
 204
 205                 iov[niov].iov_base = cp;
 206                 iov[niov].iov_len = endp - cp;
 207                 ++niov;
 208               }
 209               break;
 210
 211             case 's':
 212               /* Get the string argument.  */
 213               iov[niov].iov_base = va_arg (arg, char *);
 214               iov[niov].iov_len = strlen (iov[niov].iov_base);
 215               if (prec != -1)
 216                 iov[niov].iov_len = MIN ((size_t) prec, iov[niov].iov_len);
 217               ++niov;
 218               break;
 219
 220             case '%':
 221               iov[niov].iov_base = (void *) fmt;
 222               iov[niov].iov_len = 1;
 223               ++niov;
 224               break;
 225
 226             default:
 227               assert (! "invalid format specifier");
 228             }
 229           ++fmt;
 230         }
 231       else if (*fmt == '\n')
 232         {
 233           /* See whether we have to print a single newline character.  */
 234           if (fmt == startp)
 235             {
 236               iov[niov].iov_base = (char *) startp;
 237               iov[niov++].iov_len = 1;
 238             }
 239           else
 240             /* No, just add it to the rest of the string.  */
 241             ++iov[niov - 1].iov_len;
 242
 243           /* Next line, print a tag again.  */
 244           tag_p = 1;
 245           ++fmt;
 246         }
 247     }
 248
 249   /* Finally write the result.  */
 250 #ifdef HAVE_INLINED_SYSCALLS
 251   INTERNAL_SYSCALL_DECL (err);
 252   INTERNAL_SYSCALL (writev, err, 3, fd, &iov, niov);
 253 #elif RTLD_PRIVATE_ERRNO
 254   /* We have to take this lock just to be sure we don't clobber the private
 255      errno when it's being used by another thread that cares about it.
 256      Yet we must be sure not to try calling the lock functions before
 257      the thread library is fully initialized.  */
 258   if (__builtin_expect (INTUSE (_dl_starting_up), 0))
 259     __writev (fd, iov, niov);
 260   else
 261     {
 262       __rtld_lock_lock_recursive (GL(dl_load_lock));
 263       __writev (fd, iov, niov);
 264       __rtld_lock_unlock_recursive (GL(dl_load_lock));
 265     }
 266 #else
 267   __writev (fd, iov, niov);
 268 #endif
 269 }
 270
 271
 272 /* Write to debug file.  */
 273 void
 274 _dl_debug_printf (const char *fmt, ...)
 275 {
 276   va_list arg;
 277
 278   va_start (arg, fmt);
 279   _dl_debug_vdprintf (GLRO(dl_debug_fd), 1, fmt, arg);
 280   va_end (arg);
 281 }
 282
 283
 284 /* Write to debug file but don't start with a tag.  */
 285 void
 286 _dl_debug_printf_c (const char *fmt, ...)
 287 {
 288   va_list arg;
 289
 290   va_start (arg, fmt);
 291   _dl_debug_vdprintf (GLRO(dl_debug_fd), -1, fmt, arg);
 292   va_end (arg);
 293 }
 294
 295
 296 /* Write the given file descriptor.  */
 297 void
 298 _dl_dprintf (int fd, const char *fmt, ...)
 299 {
 300   va_list arg;
 301
 302   va_start (arg, fmt);
 303   _dl_debug_vdprintf (fd, 0, fmt, arg);
 304   va_end (arg);
 305 }
 306
 307
 308 /* Test whether given NAME matches any of the names of the given object.  */
 309 int
 310 internal_function
 311 _dl_name_match_p (const char *name, const struct link_map *map)
 312 {
 313   if (strcmp (name, map->l_name) == 0)
 314     return 1;
 315
 316   struct libname_list *runp = map->l_libname;
 317
 318   while (runp != NULL)
 319     if (strcmp (name, runp->name) == 0)
 320       return 1;
 321     else
 322       runp = runp->next;
 323
 324   return 0;
 325 }