libfuse: example/cuse_client.c File Reference

libfuse

cuse_client.c File Reference
`#include <sys/types.h>`
`#include <fcntl.h>`
`#include <sys/stat.h>`
`#include <sys/ioctl.h>`
`#include <stdio.h>`
`#include <stdlib.h>`
`#include <ctype.h>`
`#include <errno.h>`
`#include "ioctl.h"`

Go to the source code of this file.

## Detailed Description

This program tests the cuse.c example file system.

Example usage (assuming that /dev/foobar is a CUSE device provided by the cuse.c example file system):

    $ cuse_client /dev/foobar s
    0

    $ echo "hello" | cuse_client /dev/foobar w 6
    Writing 6 bytes
    transferred 6 bytes (0 -> 6)

    $ cuse_client /dev/foobar s
    6

    $ cuse_client /dev/foobar r 10
    hello
    transferred 6 bytes (6 -> 6)

Compiling this example

    gcc -Wall cuse_client.c -o cuse_client

## Source Code

/*
FUSE fioclient: FUSE ioctl example client
Copyright (C) 2008 SUSE Linux Products GmbH
Copyright (C) 2008 Tejun Heo <teheo@suse.de>
This program can be distributed under the terms of the GNU GPLv2.
See the file COPYING.
*/
#include <sys/types.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include "ioctl.h"
const char *usage =
"Usage: cuse_client FIOC_FILE COMMAND\n"
"\n"
"COMMANDS\n"
" s [SIZE] : get size if SIZE is omitted, set size otherwise\n"
" r SIZE [OFF] : read SIZE bytes @ OFF (dfl 0) and output to stdout\n"
" w SIZE [OFF] : write SIZE bytes @ OFF (dfl 0) from stdin\n"
"\n";
static int do_rw(int fd, int is_read, size_t size, off_t offset,
size_t *prev_size, size_t *new_size)
{
struct fioc_rw_arg arg = { .offset = offset };
ssize_t ret;
arg.buf = calloc(1, size);
if (!arg.buf) {
fprintf(stderr, "failed to allocated %zu bytes\n", size);
return -1;
}
if (is_read) {
arg.size = size;
ret = ioctl(fd, FIOC_READ, &arg);
if (ret >= 0)
fwrite(arg.buf, 1, ret, stdout);
} else {
arg.size = fread(arg.buf, 1, size, stdin);
fprintf(stderr, "Writing %zu bytes\n", arg.size);
ret = ioctl(fd, FIOC_WRITE, &arg);
}
if (ret >= 0) {
*prev_size = arg.prev_size;
*new_size = arg.new_size;
} else
perror("ioctl");
free(arg.buf);
return ret;
}
int main(int argc, char **argv)
{
size_t param[2] = { };
size_t size, prev_size = 0, new_size = 0;
char cmd;
int fd, i, rc;
if (argc < 3)
goto usage;
fd = open(argv[1], O_RDWR);
if (fd < 0) {
perror("open");
return 1;
}
cmd = tolower(argv[2][0]);
argc -= 3;
argv += 3;
for (i = 0; i < argc; i++) {
char *endp;
param[i] = strtoul(argv[i], &endp, 0);
if (endp == argv[i] || *endp != '\0')
goto usage;
}
switch (cmd) {
case 's':
if (!argc) {
if (ioctl(fd, FIOC_GET_SIZE, &size)) {
perror("ioctl");
return 1;
}
printf("%zu\n", size);
} else {
size = param[0];
if (ioctl(fd, FIOC_SET_SIZE, &size)) {
perror("ioctl");
return 1;
}
}
return 0;
case 'r':
case 'w':
rc = do_rw(fd, cmd == 'r', param[0], param[1],
&prev_size, &new_size);
if (rc < 0)
return 1;
fprintf(stderr, "transferred %d bytes (%zu -> %zu)\n",
rc, prev_size, new_size);
return 0;
}
usage:
fprintf(stderr, "%s", usage);
return 1;
}

Definition in file cuse_client.c.