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 /* Set the CTF library client version to the specified version.  If version is
 126    zero, we just return the default library version number.  */
 127 int
 128 ctf_version (int version)
 129 {
 130   if (version < 0)
 131     {
 132       errno = EINVAL;
 133       return -1;
 134     }
 135
 136   if (version > 0)
 137     {
 138       /*  Dynamic version switching is not presently supported. */
 139       if (version != CTF_VERSION)
 140         {
 141           errno = ENOTSUP;
 142           return -1;
 143         }
 144       ctf_dprintf ("ctf_version: client using version %d\n", version);
 145       _libctf_version = version;
 146     }
 147
 148   return _libctf_version;
 149 }
 150
 151 void
 152 libctf_init_debug (void)
 153 {
 154   static int inited;
 155   if (!inited)
 156     {
 157       _libctf_debug = getenv ("LIBCTF_DEBUG") != NULL;
 158       inited = 1;
 159     }
 160 }
 161
 162 void ctf_setdebug (int debug)
 163 {
 164   /* Ensure that libctf_init_debug() has been called, so that we don't get our
 165      debugging-on-or-off smashed by the next call.  */
 166
 167   libctf_init_debug();
 168   _libctf_debug = debug;
 169   ctf_dprintf ("CTF debugging set to %i\n", debug);
 170 }
 171
 172 int ctf_getdebug (void)
 173 {
 174   return _libctf_debug;
 175 }
 176
 177 _libctf_printflike_ (1, 2)
 178 void ctf_dprintf (const char *format, ...)
 179 {
 180   if (_libctf_unlikely_ (_libctf_debug))
 181     {
 182       va_list alist;
 183
 184       va_start (alist, format);
 185       fflush (stdout);
 186       (void) fputs ("libctf DEBUG: ", stderr);
 187       (void) vfprintf (stderr, format, alist);
 188       va_end (alist);
 189     }
 190 }
 191
 192 /* Errors and warnings.  */
 193 _libctf_printflike_ (3, 4)
 194 extern void
 195 ctf_err_warn (ctf_file_t *fp, int is_warning, const char *format, ...)
 196 {
 197   va_list alist;
 198   ctf_err_warning_t *cew;
 199
 200   /* Don't bother reporting errors here: we can't do much about them if they
 201      happen.  If we're so short of memory that a tiny malloc doesn't work, a
 202      vfprintf isn't going to work either and the caller will have to rely on the
 203      ENOMEM return they'll be getting in short order anyway.  */
 204
 205   if ((cew = malloc (sizeof (ctf_err_warning_t))) == NULL)
 206     return;
 207
 208   cew->cew_is_warning = is_warning;
 209   va_start (alist, format);
 210   if (vasprintf (&cew->cew_text, format, alist) < 0)
 211     {
 212       free (cew);
 213       va_end (alist);
 214       return;
 215     }
 216   va_end (alist);
 217
 218   ctf_dprintf ("%s: %s\n", is_warning ? "error" : "warning", cew->cew_text);
 219
 220   ctf_list_append (&fp->ctf_errs_warnings, cew);
 221 }
 222
 223 /* Error-warning reporting: an 'iterator' that returns errors and warnings from
 224    the error/warning list, in order of emission.  Errors and warnings are popped
 225    after return: the caller must free the returned error-text pointer.  */
 226 char *
 227 ctf_errwarning_next (ctf_file_t *fp, ctf_next_t **it, int *is_warning)
 228 {
 229   ctf_next_t *i = *it;
 230   char *ret;
 231   ctf_err_warning_t *cew;
 232
 233   if (!i)
 234     {
 235       if ((i = ctf_next_create ()) == NULL)
 236         {
 237           ctf_set_errno (fp, ENOMEM);
 238           return NULL;
 239         }
 240
 241       i->cu.ctn_fp = fp;
 242       i->ctn_iter_fun = (void (*) (void)) ctf_errwarning_next;
 243       *it = i;
 244     }
 245
 246   if ((void (*) (void)) ctf_errwarning_next != i->ctn_iter_fun)
 247     {
 248       ctf_set_errno (fp, ECTF_NEXT_WRONGFUN);
 249       return NULL;
 250     }
 251
 252   if (fp != i->cu.ctn_fp)
 253     {
 254       ctf_set_errno (fp, ECTF_NEXT_WRONGFP);
 255       return NULL;
 256     }
 257
 258   cew = ctf_list_next (&fp->ctf_errs_warnings);
 259
 260   if (!cew)
 261     {
 262       ctf_next_destroy (i);
 263       *it = NULL;
 264       ctf_set_errno (fp, ECTF_NEXT_END);
 265       return NULL;
 266     }
 267
 268   if (is_warning)
 269     *is_warning = cew->cew_is_warning;
 270   ret = cew->cew_text;
 271   ctf_list_delete (&fp->ctf_errs_warnings, cew);
 272   free (cew);
 273   return ret;
 274 }
 275
 276 void
 277 ctf_assert_fail_internal (ctf_file_t *fp, const char *file, size_t line,
 278                           const char *exprstr)
 279 {
 280   ctf_err_warn (fp, 0, "%s: %lu: libctf assertion failed: %s", file,
 281                 (long unsigned int) line, exprstr);
 282   ctf_set_errno (fp, ECTF_INTERNAL);
 283 }