ctf-subr.c revision 1.1.1.1 
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
29int _libctf_version = CTF_VERSION;	      /* Library client version.  */
30int _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 *
37ctf_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
58void
59ctf_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
68ssize_t
69ctf_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
125const char *
126ctf_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.  */
133int
134ctf_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
157void
158libctf_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
168void 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
178int ctf_getdebug (void)
179{
180  return _libctf_debug;
181}
182
183_libctf_printflike_ (1, 2)
184void 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}
197