92 lines
1.7 KiB
C
92 lines
1.7 KiB
C
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/*
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* Microcontroller Message Bus
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* Userspace commandline utility
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*
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* Copyright (c) 2009 Michael Buesch <mb@bu3sch.de>
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*
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* Licensed under the GNU/GPL. See COPYING for details.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#define UCMB_DEV "/dev/ucmb"
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static void usage(int argc, char **argv)
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{
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fprintf(stderr, "Usage: %s read|write\n", argv[0]);
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}
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int main(int argc, char **argv)
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{
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const char *command;
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int errcode = 0;
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int ucmb_fd;
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char *buf;
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size_t count, buflen;
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ssize_t nrbytes;
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if (argc != 2) {
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usage(argc, argv);
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return 1;
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}
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command = argv[1];
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ucmb_fd = open(UCMB_DEV, O_RDWR);
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if (ucmb_fd == -1) {
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fprintf(stderr, "Failed to open %s\n", UCMB_DEV);
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errcode = 1;
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goto out;
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}
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buflen = 4096;
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buf = malloc(buflen);
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if (!buf) {
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fprintf(stderr, "Out of memory\n");
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errcode = 1;
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goto out_close;
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}
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if (strcasecmp(command, "read") == 0) {
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nrbytes = read(ucmb_fd, buf, buflen);
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if (nrbytes < 0) {
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fprintf(stderr, "Failed to read UCMB: %s (%d)\n",
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strerror(errno), errno);
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goto out_free;
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}
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if (fwrite(buf, nrbytes, 1, stdout) != 1) {
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fprintf(stderr, "Failed to write stdout\n");
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goto out_free;
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}
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} else if (strcasecmp(command, "write") == 0) {
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count = fread(buf, 1, buflen, stdin);
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if (!count) {
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fprintf(stderr, "Failed to read stdin\n");
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goto out_free;
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}
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nrbytes = write(ucmb_fd, buf, count);
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if (nrbytes != count) {
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fprintf(stderr, "Failed to write UCMB: %s (%d)\n",
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strerror(errno), errno);
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goto out_free;
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}
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} else {
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usage(argc, argv);
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errcode = 1;
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goto out_free;
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}
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out_free:
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free(buf);
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out_close:
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close(ucmb_fd);
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out:
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return errcode;
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}
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