include/babeltrace/compat/stdio.h

   1 #ifndef _BABELTRACE_COMPAT_STDIO_H
   2 #define _BABELTRACE_COMPAT_STDIO_H
   3
   4 /*
   5  * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24  */
  25
  26 #include <stdio.h>
  27 #include <errno.h>
  28 #include <assert.h>
  29
  30 #define BT_GETLINE_MINBUFLEN    64
  31
  32 static inline
  33 char * _bt_getline_bufalloc(char **lineptr, size_t *n, size_t linelen)
  34 {
  35         size_t buflen = *n;
  36         char *buf = *lineptr;
  37
  38         if (buflen >= linelen && buf != NULL) {
  39                 return buf;
  40         }
  41         if (buf == NULL) {
  42                 buflen = BT_GETLINE_MINBUFLEN;
  43         } else {
  44                 buflen = buflen << 1;
  45                 if (buflen < BT_GETLINE_MINBUFLEN) {
  46                         buflen = BT_GETLINE_MINBUFLEN;
  47                 }
  48         }
  49         /* Check below not strictly needed, extra safety. */
  50         if (buflen < linelen) {
  51                 buflen = linelen;
  52         }
  53         buf = realloc(buf, buflen);
  54         if (!buf) {
  55                 errno = ENOMEM;
  56                 return NULL;
  57         }
  58         *n = buflen;
  59         *lineptr = buf;
  60         return buf;
  61 }
  62
  63 /*
  64  * Returns line length (including possible final \n, excluding final
  65  * \0). On end of file, returns -1 with nonzero feof(stream) and errno
  66  * set to 0. On error, returns -1 with errno set.
  67  *
  68  * This interface is similar to the getline(3) man page part of the
  69  * Linux man-pages project, release 3.74. One major difference from the
  70  * Open Group POSIX specification is that this implementation does not
  71  * necessarily set the ferror() flag on error (because it is internal to
  72  * libc).
  73  */
  74 static inline
  75 ssize_t bt_getline(char **lineptr, size_t *n, FILE *stream)
  76 {
  77         size_t linelen = 0;
  78         char *buf;
  79         int found_eof = 0;
  80
  81         if (lineptr == NULL || n == NULL) {
  82                 errno = EINVAL;
  83                 return -1;
  84         }
  85         for (;;) {
  86                 char c;
  87
  88                 c = fgetc(stream);
  89                 if (c == EOF) {
  90                         if (ferror(stream)) {
  91                                 /* ferror() is set, errno set by fgetc(). */
  92                                 return -1;
  93                         }
  94                         assert(feof(stream));
  95                         found_eof = 1;
  96                         break;
  97                 }
  98                 if (linelen == SSIZE_MAX) {
  99                         errno = EOVERFLOW;
 100                         return -1;
 101                 }
 102                 buf = _bt_getline_bufalloc(lineptr, n, ++linelen);
 103                 if (!buf) {
 104                         return -1;
 105                 }
 106                 buf[linelen - 1] = c;
 107                 if (c == '\n') {
 108                         break;
 109                 }
 110         }
 111         if (!linelen && found_eof) {
 112                 /* feof() is set. */
 113                 errno = 0;
 114                 return -1;
 115         }
 116         buf = _bt_getline_bufalloc(lineptr, n, ++linelen);
 117         if (!buf) {
 118                 return -1;
 119         }
 120         buf[linelen - 1] = '\0';
 121         return linelen - 1;     /* Count don't include final \0. */
 122 }
 123
 124 #endif /* _BABELTRACE_COMPAT_STDIO_H */