libfuse: example/cuse_client.c Source File

libfuse

cuse_client.c
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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 GPLv2.
7 See the file GPL2.txt.
8*/
9
40#include <sys/types.h>
41#include <fcntl.h>
42#include <sys/stat.h>
43#include <sys/ioctl.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <ctype.h>
47#include <errno.h>
48#include <unistd.h>
49#include "ioctl.h"
50
51const char *usage =
52"Usage: cuse_client FIOC_FILE COMMAND\n"
53"\n"
54"COMMANDS\n"
55" s [SIZE] : get size if SIZE is omitted, set size otherwise\n"
56" r SIZE [OFF] : read SIZE bytes @ OFF (dfl 0) and output to stdout\n"
57" w SIZE [OFF] : write SIZE bytes @ OFF (dfl 0) from stdin\n"
58"\n";
59
60static int do_rw(int fd, int is_read, size_t size, off_t offset,
61 size_t *prev_size, size_t *new_size)
62{
63 struct fioc_rw_arg arg = { .offset = offset };
64 ssize_t ret;
65
66 arg.buf = calloc(1, size);
67 if (!arg.buf) {
68 fprintf(stderr, "failed to allocated %zu bytes\n", size);
69 return -1;
70 }
71
72 if (is_read) {
73 arg.size = size;
74 ret = ioctl(fd, FIOC_READ, &arg);
75 if (ret >= 0)
76 fwrite(arg.buf, 1, ret, stdout);
77 } else {
78 arg.size = fread(arg.buf, 1, size, stdin);
79 fprintf(stderr, "Writing %zu bytes\n", arg.size);
80 ret = ioctl(fd, FIOC_WRITE, &arg);
81 }
82
83 if (ret >= 0) {
84 *prev_size = arg.prev_size;
85 *new_size = arg.new_size;
86 } else
87 perror("ioctl");
88
89 free(arg.buf);
90 return ret;
91}
92
93int main(int argc, char **argv)
94{
95 size_t param[2] = { };
96 size_t size, prev_size = 0, new_size = 0;
97 char cmd;
98 int fd, i, rc;
99
100 if (argc < 3)
101 goto usage;
102
103 fd = open(argv[1], O_RDWR);
104 if (fd < 0) {
105 perror("open");
106 return 1;
107 }
108
109 cmd = tolower(argv[2][0]);
110 argc -= 3;
111 argv += 3;
112
113 for (i = 0; i < argc; i++) {
114 char *endp;
115 param[i] = strtoul(argv[i], &endp, 0);
116 if (endp == argv[i] || *endp != '\0')
117 goto usage;
118 }
119
120 switch (cmd) {
121 case 's':
122 if (!argc) {
123 if (ioctl(fd, FIOC_GET_SIZE, &size)) {
124 perror("ioctl");
125 goto error;
126 }
127 printf("%zu\n", size);
128 } else {
129 size = param[0];
130 if (ioctl(fd, FIOC_SET_SIZE, &size)) {
131 perror("ioctl");
132 goto error;
133 }
134 }
135 close(fd);
136 return 0;
137
138 case 'r':
139 case 'w':
140 rc = do_rw(fd, cmd == 'r', param[0], param[1],
141 &prev_size, &new_size);
142 if (rc < 0)
143 goto error;
144 fprintf(stderr, "transferred %d bytes (%zu -> %zu)\n",
145 rc, prev_size, new_size);
146 close(fd);
147 return 0;
148 }
149
150usage:
151 fprintf(stderr, "%s", usage);
152 return 1;
153
154error:
155 close(fd);
156 return 1;
157}
ioctl.h