libctf/ctf-subr.c

   1 /* Simple subrs.
   2    Copyright (C) 2019-2020 Free Software Foundation, Inc.
   3
   4    This file is part of libctf.
   5
   6    libctf is free software; you can redistribute it and/or modify it under
   7    the terms of the GNU General Public License as published by the Free
   8    Software Foundation; either version 3, or (at your option) any later
   9    version.
  10
  11    This program is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  14    See the GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; see the file COPYING.  If not see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <ctf-impl.h>
  21 #ifdef HAVE_MMAP
  22 #include <sys/mman.h>
  23 #endif
  24 #include <sys/types.h>
  25 #include <stdarg.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28
  29 int _libctf_version = CTF_VERSION;            /* Library client version.  */
  30 int _libctf_debug = 0;                        /* Debugging messages enabled.  */
  31
  32 /* Private, read-only mmap from a file, with fallback to copying.
  33
  34    No handling of page-offset issues at all: the caller must allow for that. */
  35
  36 _libctf_malloc_ void *
  37 ctf_mmap (size_t length, size_t offset, int fd)
  38 {
  39   void *data;
  40
  41 #ifdef HAVE_MMAP
  42   data = mmap (NULL, length, PROT_READ, MAP_PRIVATE, fd, offset);
  43   if (data == MAP_FAILED)
  44     data = NULL;
  45 #else
  46   if ((data = malloc (length)) != NULL)
  47     {
  48       if (ctf_pread (fd, data, length, offset) <= 0)
  49         {
  50           free (data);
  51           data = NULL;
  52         }
  53     }
  54 #endif
  55   return data;
  56 }
  57
  58 void
  59 ctf_munmap (void *buf, size_t length _libctf_unused_)
  60 {
  61 #ifdef HAVE_MMAP
  62   (void) munmap (buf, length);
  63 #else
  64   free (buf);
  65 #endif
  66 }
  67
  68 ssize_t
  69 ctf_pread (int fd, void *buf, ssize_t count, off_t offset)
  70 {
  71   ssize_t len;
  72   size_t acc = 0;
  73   char *data = (char *) buf;
  74
  75 #ifdef HAVE_PREAD
  76   while (count > 0)
  77     {
  78       errno = 0;
  79       if (((len = pread (fd, data, count, offset)) < 0) &&
  80           errno != EINTR)
  81           return len;
  82       if (errno == EINTR)
  83         continue;
  84
  85       acc += len;
  86       if (len == 0)                             /* EOF.  */
  87         return acc;
  88
  89       count -= len;
  90       offset += len;
  91       data += len;
  92     }
  93   return acc;
  94 #else
  95   off_t orig_off;
  96
  97   if ((orig_off = lseek (fd, 0, SEEK_CUR)) < 0)
  98     return -1;
  99   if ((lseek (fd, offset, SEEK_SET)) < 0)
 100     return -1;
 101
 102   while (count > 0)
 103     {
 104       errno = 0;
 105       if (((len = read (fd, data, count)) < 0) &&
 106           errno != EINTR)
 107           return len;
 108       if (errno == EINTR)
 109         continue;
 110
 111       acc += len;
 112       if (len == 0)                             /* EOF.  */
 113         break;
 114
 115       count -= len;
 116       data += len;
 117     }
 118   if ((lseek (fd, orig_off, SEEK_SET)) < 0)
 119     return -1;                                  /* offset is smashed.  */
 120 #endif
 121
 122   return acc;
 123 }
 124
 125 const char *
 126 ctf_strerror (int err)
 127 {
 128   return (const char *) (strerror (err));
 129 }
 130
 131 /* Set the CTF library client version to the specified version.  If version is
 132    zero, we just return the default library version number.  */
 133 int
 134 ctf_version (int version)
 135 {
 136   if (version < 0)
 137     {
 138       errno = EINVAL;
 139       return -1;
 140     }
 141
 142   if (version > 0)
 143     {
 144       /*  Dynamic version switching is not presently supported. */
 145       if (version != CTF_VERSION)
 146         {
 147           errno = ENOTSUP;
 148           return -1;
 149         }
 150       ctf_dprintf ("ctf_version: client using version %d\n", version);
 151       _libctf_version = version;
 152     }
 153
 154   return _libctf_version;
 155 }
 156
 157 void
 158 libctf_init_debug (void)
 159 {
 160   static int inited;
 161   if (!inited)
 162     {
 163       _libctf_debug = getenv ("LIBCTF_DEBUG") != NULL;
 164       inited = 1;
 165     }
 166 }
 167
 168 void ctf_setdebug (int debug)
 169 {
 170   /* Ensure that libctf_init_debug() has been called, so that we don't get our
 171      debugging-on-or-off smashed by the next call.  */
 172
 173   libctf_init_debug();
 174   _libctf_debug = debug;
 175   ctf_dprintf ("CTF debugging set to %i\n", debug);
 176 }
 177
 178 int ctf_getdebug (void)
 179 {
 180   return _libctf_debug;
 181 }
 182
 183 _libctf_printflike_ (1, 2)
 184 void ctf_dprintf (const char *format, ...)
 185 {
 186   if (_libctf_debug)
 187     {
 188       va_list alist;
 189
 190       va_start (alist, format);
 191       fflush (stdout);
 192       (void) fputs ("libctf DEBUG: ", stderr);
 193       (void) vfprintf (stderr, format, alist);
 194       va_end (alist);
 195     }
 196 }