example/fioclient.c

   1 /*
   2   FUSE fioclient: FUSE ioctl example client
   3   Copyright (C) 2008       SUSE Linux Products GmbH
   4   Copyright (C) 2008       Tejun Heo <teheo@suse.de>
   5
   6   This program can be distributed under the terms of the GNU GPL.
   7   See the file COPYING.
   8
   9   gcc -Wall fioclient.c -o fioclient
  10 */
  11
  12 #include <sys/types.h>
  13 #include <sys/fcntl.h>
  14 #include <sys/stat.h>
  15 #include <sys/ioctl.h>
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <ctype.h>
  19 #include <errno.h>
  20 #include "fioc.h"
  21
  22 const char *usage =
  23 "Usage: fioclient FIOC_FILE COMMAND\n"
  24 "\n"
  25 "COMMANDS\n"
  26 "  s [SIZE]     : get size if SIZE is omitted, set size otherwise\n"
  27 "  r SIZE [OFF] : read SIZE bytes @ OFF (dfl 0) and output to stdout\n"
  28 "  w SIZE [OFF] : write SIZE bytes @ OFF (dfl 0) from stdin\n"
  29 "\n";
  30
  31 static int do_rw(int fd, int is_read, size_t size, off_t offset,
  32                  size_t *prev_size, size_t *new_size)
  33 {
  34         struct fioc_rw_arg arg = { .offset = offset };
  35         ssize_t ret;
  36
  37         arg.buf = calloc(1, size);
  38         if (!arg.buf) {
  39                 fprintf(stderr, "failed to allocated %zu bytes\n", size);
  40                 return -1;
  41         }
  42
  43         if (is_read) {
  44                 arg.size = size;
  45                 ret = ioctl(fd, FIOC_READ, &arg);
  46                 if (ret >= 0)
  47                         fwrite(arg.buf, 1, ret, stdout);
  48         } else {
  49                 arg.size = fread(arg.buf, 1, size, stdin);
  50                 fprintf(stderr, "Writing %zu bytes\n", arg.size);
  51                 ret = ioctl(fd, FIOC_WRITE, &arg);
  52         }
  53
  54         if (ret >= 0) {
  55                 *prev_size = arg.prev_size;
  56                 *new_size = arg.new_size;
  57         } else
  58                 perror("ioctl");
  59
  60         free(arg.buf);
  61         return ret;
  62 }
  63
  64 int main(int argc, char **argv)
  65 {
  66         size_t param[2] = { };
  67         size_t size, prev_size = 0, new_size = 0;
  68         char cmd;
  69         int fd, i, rc;
  70
  71         if (argc < 3)
  72                 goto usage;
  73
  74         fd = open(argv[1], O_RDWR);
  75         if (fd < 0) {
  76                 perror("open");
  77                 return 1;
  78         }
  79
  80         cmd = tolower(argv[2][0]);
  81         argc -= 3;
  82         argv += 3;
  83
  84         for (i = 0; i < argc; i++) {
  85                 char *endp;
  86                 param[i] = strtoul(argv[i], &endp, 0);
  87                 if (endp == argv[i] || *endp != '\0')
  88                         goto usage;
  89         }
  90
  91         switch (cmd) {
  92         case 's':
  93                 if (!argc) {
  94                         if (ioctl(fd, FIOC_GET_SIZE, &size)) {
  95                                 perror("ioctl");
  96                                 return 1;
  97                         }
  98                         printf("%zu\n", size);
  99                 } else {
 100                         size = param[0];
 101                         if (ioctl(fd, FIOC_SET_SIZE, &size)) {
 102                                 perror("ioctl");
 103                                 return 1;
 104                         }
 105                 }
 106                 return 0;
 107
 108         case 'r':
 109         case 'w':
 110                 rc = do_rw(fd, cmd == 'r', param[0], param[1],
 111                            &prev_size, &new_size);
 112                 if (rc < 0)
 113                         return 1;
 114                 fprintf(stderr, "transferred %d bytes (%zu -> %zu)\n",
 115                         rc, prev_size, new_size);
 116                 return 0;
 117         }
 118
 119  usage:
 120         fprintf(stderr, "%s", usage);
 121         return 1;
 122 }