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 }
197