utils.c

   1 /*
   2     Copyright (C) 2007-2009 Proxmox Server Solutions GmbH
   3
   4     Copyright: vzdump is under GNU GPL, the GNU General Public License.
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; version 2 dated June, 1991.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the
  17     Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  18     MA 02110-1301, USA.
  19
  20     Author: Dietmar Maurer <dietmar@proxmox.com>
  21
  22 */
  23
  24 #define _GNU_SOURCE
  25
  26 #include <sys/types.h>
  27 #include <sys/stat.h>
  28 #include <fcntl.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <unistd.h>
  32 #include <errno.h>
  33 #include <string.h>
  34 #include <signal.h>
  35
  36 /* Set a signal handler */
  37 static void
  38 setsig (struct sigaction *sa, int sig, void (*fun)(int), int flags)
  39 {
  40   sa->sa_handler = fun;
  41   sa->sa_flags = flags;
  42   sigemptyset(&sa->sa_mask);
  43   sigaction(sig, sa, NULL);
  44 }
  45
  46 int
  47 block_is_zero (char const *buffer, size_t size)
  48 {
  49   while (size--)
  50     if (*buffer++)
  51       return 0;
  52
  53   return 1;
  54 }
  55
  56 ssize_t
  57 safe_read(int fd, char *buf, size_t count)
  58 {
  59   ssize_t n;
  60
  61   do {
  62     n = read(fd, buf, count);
  63   } while (n < 0 && errno == EINTR);
  64
  65   return n;
  66 }
  67
  68 int
  69 full_read(int fd, char *buf, size_t len)
  70 {
  71   ssize_t n;
  72   size_t total;
  73
  74   total = 0;
  75
  76   while (len > 0) {
  77     n = safe_read(fd, buf, len);
  78
  79     if (n == 0)
  80             return total;
  81
  82     if (n < 0)
  83             break;
  84
  85     buf += n;
  86     total += n;
  87     len -= n;
  88   }
  89
  90   if (len) {
  91           fprintf (stderr, "ERROR: incomplete read detected\n");
  92           exit (-1);
  93   }
  94
  95   return total;
  96 }
  97
  98 ssize_t
  99 safe_write(int fd, char *buf, size_t count)
 100 {
 101   ssize_t n;
 102
 103   do {
 104     n = write(fd, buf, count);
 105   } while (n < 0 && errno == EINTR);
 106
 107   return n;
 108 }
 109
 110 int
 111 full_write(int fd, char *buf, size_t len)
 112 {
 113   ssize_t n;
 114   size_t total;
 115
 116   total = 0;
 117
 118   while (len > 0) {
 119     n = safe_write(fd, buf, len);
 120
 121     if (n < 0)
 122       break;
 123
 124     buf += n;
 125     total += n;
 126     len -= n;
 127   }
 128
 129   if (len) {
 130     fprintf (stderr, "ERROR: incomplete write detected\n");
 131     exit (-1);
 132   }
 133
 134   return total;
 135 }