tailf sourcecode

tailf.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <malloc.h>
#include <sys/stat.h>
#include <signal.h>
//#include "mongo.h"
#define _(s) s

static size_t filesize(const char *filename)
{
    struct stat sb;

    if (!stat(filename, &sb)) return sb.st_size;
    return 0;
}

static void tailf(const char *filename, int lines)
{
    char **buffer;
    int  head = 0;
    int  tail = 0;
    FILE *str;
    int  i;

    if (!(str = fopen(filename, "r"))) {
    }

    buffer = malloc(lines * sizeof(*buffer));
    for (i = 0; i < lines; i++) buffer[i] = malloc(BUFSIZ + 1);

    while (fgets(buffer[tail], BUFSIZ, str)) {
        if (++tail >= lines) {
            tail = 0;
            head = 1;
        }
    }
    if (head) {
        for (i = tail; i < lines; i++) fputs(buffer[i], stdout);
        for (i = 0; i < tail; i++)     fputs(buffer[i], stdout);
    } else {
        for (i = head; i < tail; i++)  fputs(buffer[i], stdout);
    }
    fflush(stdout); 

    for (i = 0; i < lines; i++) free(buffer[i]);
    free(buffer);
}
void restart(int num)
    {

    }

int main(int argc, char **argv)
{
    char       buffer[BUFSIZ];
    size_t     osize, nsize;
    FILE       *str;
    const char *filename;
    int        count;
    int signum =11;
    signal(signum, restart);
    if (argc != 2) {
        fprintf(stderr, _("Usage: tailf logfile\n"));
    }

    filename = argv[1];
    tailf(filename, 1);

    for (osize = filesize(filename);;) {
        nsize = filesize(filename);
        if (nsize != osize) {
            if (!(str = fopen(filename, "r"))) {
        }
            if (!fseek(str, osize, SEEK_SET))
                while ((count = fread(buffer, 1, sizeof(buffer), str)) > 0)
                    buffer[count+1] = '\0';
                    printf(buffer,1,count);
                    printf("####################################");
            fclose(str);
            osize = nsize;
        }
        usleep(250000);         /* 250mS */
    }
    return 0;
}
;