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
  10 /** @file
  11  * @tableofcontents
  12  *
  13  * fioclient.c - FUSE fioclient: FUSE ioctl example client
  14  *
  15  * \section section_compile compiling this example
  16  *
  17  * gcc -Wall fioclient.c -o fioclient
  18  *
  19  * \section section_source the complete source
  20  * fioclient.c
  21  * \include fioclient.c
  22  */
  23
  24 #include <config.h>
  25
  26 #include <sys/types.h>
  27 #include <sys/fcntl.h>
  28 #include <sys/stat.h>
  29 #include <sys/ioctl.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <ctype.h>
  33 #include <errno.h>
  34 #include "fioc.h"
  35
  36 const char *usage =
  37 "Usage: fioclient FIOC_FILE COMMAND\n"
  38 "\n"
  39 "COMMANDS\n"
  40 "  s [SIZE]     : get size if SIZE is omitted, set size otherwise\n"
  41 "  r SIZE [OFF] : read SIZE bytes @ OFF (dfl 0) and output to stdout\n"
  42 "  w SIZE [OFF] : write SIZE bytes @ OFF (dfl 0) from stdin\n"
  43 "\n";
  44
  45 static int do_rw(int fd, int is_read, size_t size, off_t offset,
  46                  size_t *prev_size, size_t *new_size)
  47 {
  48         struct fioc_rw_arg arg = { .offset = offset };
  49         ssize_t ret;
  50
  51         arg.buf = calloc(1, size);
  52         if (!arg.buf) {
  53                 fprintf(stderr, "failed to allocated %zu bytes\n", size);
  54                 return -1;
  55         }
  56
  57         if (is_read) {
  58                 arg.size = size;
  59                 ret = ioctl(fd, FIOC_READ, &arg);
  60                 if (ret >= 0)
  61                         fwrite(arg.buf, 1, ret, stdout);
  62         } else {
  63                 arg.size = fread(arg.buf, 1, size, stdin);
  64                 fprintf(stderr, "Writing %zu bytes\n", arg.size);
  65                 ret = ioctl(fd, FIOC_WRITE, &arg);
  66         }
  67
  68         if (ret >= 0) {
  69                 *prev_size = arg.prev_size;
  70                 *new_size = arg.new_size;
  71         } else
  72                 perror("ioctl");
  73
  74         free(arg.buf);
  75         return ret;
  76 }
  77
  78 int main(int argc, char **argv)
  79 {
  80         size_t param[2] = { };
  81         size_t size, prev_size = 0, new_size = 0;
  82         char cmd;
  83         int fd, i, rc;
  84
  85         if (argc < 3)
  86                 goto usage;
  87
  88         fd = open(argv[1], O_RDWR);
  89         if (fd < 0) {
  90                 perror("open");
  91                 return 1;
  92         }
  93
  94         cmd = tolower(argv[2][0]);
  95         argc -= 3;
  96         argv += 3;
  97
  98         for (i = 0; i < argc; i++) {
  99                 char *endp;
 100                 param[i] = strtoul(argv[i], &endp, 0);
 101                 if (endp == argv[i] || *endp != '\0')
 102                         goto usage;
 103         }
 104
 105         switch (cmd) {
 106         case 's':
 107                 if (!argc) {
 108                         if (ioctl(fd, FIOC_GET_SIZE, &size)) {
 109                                 perror("ioctl");
 110                                 return 1;
 111                         }
 112                         printf("%zu\n", size);
 113                 } else {
 114                         size = param[0];
 115                         if (ioctl(fd, FIOC_SET_SIZE, &size)) {
 116                                 perror("ioctl");
 117                                 return 1;
 118                         }
 119                 }
 120                 return 0;
 121
 122         case 'r':
 123         case 'w':
 124                 rc = do_rw(fd, cmd == 'r', param[0], param[1],
 125                            &prev_size, &new_size);
 126                 if (rc < 0)
 127                         return 1;
 128                 fprintf(stderr, "transferred %d bytes (%zu -> %zu)\n",
 129                         rc, prev_size, new_size);
 130                 return 0;
 131         }
 132
 133  usage:
 134         fprintf(stderr, "%s", usage);
 135         return 1;
 136 }