src/utils.c

   1 /* nbdkit
   2  * Copyright (C) 2013 Red Hat Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met:
   8  *
   9  * * Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  *
  12  * * Redistributions in binary form must reproduce the above copyright
  13  * notice, this list of conditions and the following disclaimer in the
  14  * documentation and/or other materials provided with the distribution.
  15  *
  16  * * Neither the name of Red Hat nor the names of its contributors may be
  17  * used to endorse or promote products derived from this software without
  18  * specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  22  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  23  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  27  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  28  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  30  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <config.h>
  35
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <stdbool.h>
  39 #include <stdint.h>
  40 #include <inttypes.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43 #include <errno.h>
  44
  45 #include "nbdkit-plugin.h"
  46 #include "internal.h"
  47
  48 char *
  49 nbdkit_absolute_path (const char *path)
  50 {
  51   CLEANUP_FREE char *pwd = NULL;
  52   char *ret;
  53
  54   if (path == NULL || *path == '\0') {
  55     nbdkit_error ("cannot convert null or empty path to an absolute path");
  56     return NULL;
  57   }
  58
  59   if (*path == '/') {
  60     ret = strdup (path);
  61     if (!ret) {
  62       nbdkit_error ("strdup: %m");
  63       return NULL;
  64     }
  65     return ret;
  66   }
  67
  68   pwd = get_current_dir_name ();
  69   if (pwd == NULL) {
  70     nbdkit_error ("get_current_dir_name: %m");
  71     return NULL;
  72   }
  73
  74   if (asprintf (&ret, "%s/%s", pwd, path) == -1) {
  75     nbdkit_error ("asprintf: %m");
  76     return NULL;
  77   }
  78
  79   return ret;
  80 }
  81
  82 /* XXX Multiple problems with this function.  Really we should use the
  83  * 'human*' functions from gnulib.
  84  */
  85 int64_t
  86 nbdkit_parse_size (const char *str)
  87 {
  88   uint64_t size;
  89   char t;
  90
  91   if (sscanf (str, "%" SCNu64, &size) == 1)
  92     return (int64_t) size;
  93   if (sscanf (str, "%" SCNu64 "%c", &size, &t) == 2) {
  94     switch (t) {
  95     case 'b': case 'B':
  96       return (int64_t) size;
  97     case 'k': case 'K':
  98       return (int64_t) size * 1024;
  99     case 'm': case 'M':
 100       return (int64_t) size * 1024 * 1024;
 101     case 'g': case 'G':
 102       return (int64_t) size * 1024 * 1024 * 1024;
 103     case 't': case 'T':
 104       return (int64_t) size * 1024 * 1024 * 1024 * 1024;
 105     case 'p': case 'P':
 106       return (int64_t) size * 1024 * 1024 * 1024 * 1024 * 1024;
 107     case 'e': case 'E':
 108       return (int64_t) size * 1024 * 1024 * 1024 * 1024 * 1024 * 1024;
 109
 110     case 's': case 'S':         /* "sectors", ie. units of 512 bytes,
 111                                  * even if that's not the real sector size
 112                                  */
 113       return (int64_t) size * 512;
 114
 115     default:
 116       nbdkit_error ("could not parse size: unknown specifier '%c'", t);
 117       return -1;
 118     }
 119   }
 120
 121   nbdkit_error ("could not parse size string (%s)", str);
 122   return -1;
 123 }
 124
 125 /* Write buffer to socket and either succeed completely (returns 0)
 126  * or fail (returns -1).
 127  */
 128 int
 129 xwrite (int sock, const void *vbuf, size_t len)
 130 {
 131   const char *buf = vbuf;
 132   ssize_t r;
 133
 134   while (len > 0) {
 135     r = write (sock, buf, len);
 136     if (r == -1) {
 137       if (errno == EINTR || errno == EAGAIN)
 138         continue;
 139       return -1;
 140     }
 141     buf += r;
 142     len -= r;
 143   }
 144
 145   return 0;
 146 }
 147
 148 /* Read buffer from socket and either succeed completely (returns > 0),
 149  * read an EOF (returns 0), or fail (returns -1).
 150  */
 151 int
 152 xread (int sock, void *vbuf, size_t len)
 153 {
 154   char *buf = vbuf;
 155   ssize_t r;
 156   bool first_read = true;
 157
 158   while (len > 0) {
 159     r = read (sock, buf, len);
 160     if (r == -1) {
 161       if (errno == EINTR || errno == EAGAIN)
 162         continue;
 163       return -1;
 164     }
 165     if (r == 0) {
 166       if (first_read)
 167         return 0;
 168       /* Partial record read.  This is an error. */
 169       errno = EBADMSG;
 170       return -1;
 171     }
 172     first_read = false;
 173     buf += r;
 174     len -= r;
 175   }
 176
 177   return 1;
 178 }