root / rfid-web / main.c @ f3599378
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1 | f3599378 | Tom Mullins | #include <sys/types.h> |
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2 | #include <sys/stat.h> |
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3 | #include <fcntl.h> |
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4 | #include <termios.h> |
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5 | #include <unistd.h> |
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6 | #include <stdio.h> |
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7 | #include <stdarg.h> |
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8 | #include <stdlib.h> |
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9 | #include <string.h> |
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10 | |||
11 | #define RFID_OK 1 |
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12 | static char read_cmd[] = {'!', 'R', 'W', 1, 32}; |
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13 | static int serno; |
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14 | |||
15 | void init_tty(int fd) { |
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16 | struct termios ios;
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17 | bzero(&ios, sizeof(ios));
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18 | ios.c_cflag = B9600 | CS8 | CREAD; |
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19 | tcsetattr(fd, TCSAFLUSH, &ios); |
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20 | } |
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21 | |||
22 | int bswap(int x) { |
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23 | return ((x&0xff) << 24) | ((x&0xff00) << 8) |
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24 | | ((x>>8) & 0xff00) | ((x>>24) & 0xff); |
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25 | } |
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26 | |||
27 | void read_all(int fd, void *buf, int n) { |
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28 | int nread;
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29 | while (n > 0) { |
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30 | nread = read(fd, buf, n); |
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31 | buf += nread; |
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32 | n -= nread; |
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33 | usleep(10000);
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34 | } |
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35 | } |
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36 | |||
37 | void write_all(int fd, void *buf, int n) { |
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38 | int nwritten;
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39 | while (n > 0) { |
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40 | nwritten = write(fd, buf, n); |
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41 | buf += nwritten; |
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42 | n -= nwritten; |
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43 | usleep(10000);
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44 | } |
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45 | } |
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46 | |||
47 | void fail_error(const char *error, ...) { |
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48 | va_list args; |
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49 | va_start(args, error); |
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50 | printf("Status: 500 Internal Server Error\n");
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51 | printf("Content-type: text/plain\n\n");
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52 | vprintf(error, args); |
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53 | va_end(args); |
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54 | exit(0);
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55 | } |
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56 | |||
57 | int main(int argc, char **argv) { |
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58 | int fd;
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59 | char status;
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60 | |||
61 | fd = open("/dev/ttyUSB0", O_RDWR | O_NOCTTY);
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62 | if (fd < 0) |
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63 | fail_error("Could not open /dev/ttyUSB0\n");
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64 | |||
65 | init_tty(fd); |
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66 | tcflush(fd, TCIFLUSH); |
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67 | write_all(fd, read_cmd, sizeof(read_cmd));
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68 | |||
69 | read_all(fd, &status, 1);
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70 | if (status == RFID_OK) {
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71 | read_all(fd, &serno, 4);
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72 | serno = bswap(serno); |
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73 | printf("Content-type: text/plain\n\n");
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74 | printf("%08x\n", serno);
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75 | } else {
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76 | fail_error("Reader gave error %d\n", (int)(unsigned char)status); |
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77 | } |
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78 | |||
79 | close(fd); |
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80 | return 0; |
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81 | } |