Read named pipes and print the decimal and hex value.

read_fifo.c

/* Build for STB: /opt/CodeSourcery/mips-4.4/bin/mips-linux-gnu-gcc -EL read_fifo.c -o read_fifo */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include <sys/time.h>
#include <sys/types.h>
#include <sys/select.h>
#include <sys/stat.h>
#include <sys/ioctl.h>

#include <fcntl.h>

int main(int argc, char *argv[])
{
    int readlen, i;
    int fifo_fd = 0;
    int retries = 60;

    if (argc != 2)
    {
        printf("USAGE: %s [pipe]\n", argv[0]);
        return -1;
    }

    // Open named pipe for read
    while( (fifo_fd = open(argv[1], O_RDONLY)) == -1 )
    {
        if (retries--)
        {
            if (fifo_fd)
            {
                printf("ERROR: Pipe %s could not be opened, retry in 1 second\n", argv[1]);
                fifo_fd = 0;
            }
            else
            {
                printf("ERROR: Pipe %s is locked, retry in 1 second\n", argv[1]);
            }

            sleep(1);
            continue;
        }

        printf("ERROR: Could not open pipe %s, give up\n", argv[1]);
    }

    while(1)
    {
        unsigned int code = 0;
        struct timeval tv;
        int res;
        fd_set fds;

        FD_ZERO(&fds);
        FD_SET(fifo_fd, &fds);

        tv.tv_sec = 0;
        tv.tv_usec = 150;

        // Check if pipe is ready for a timeout of 150 usec...
        res = select(FD_SETSIZE, &fds, NULL, NULL, &tv);
        if (res == 0) // The timeout expires, so continue...
            continue;

        // Read 4 bytes and put them on code...
        readlen = read(fifo_fd, &code, 4);

        if (readlen == 0)
            continue;

        if (readlen < 0)
        {
            printf("ERROR: readlen < 0\n");
            break;
        }

        if (readlen > 0)
        {
            time_t tm = 0;
            tm = time (NULL);
            printf("%ld - Data read(Read %d bytes): %ld (0x%x)\n", tm, readlen, code, code);
        }
    }

    if (readlen < 0 && errno != EINTR)
        printf("Fatal Error\n");

    return 0;
}