b7ping

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#define xstr(s) str(s)
#define str(s) #s
#define NUM_COPS 5
#define DELAY    0.5

int do_ping(const char *url, double *time)
{
    double acum = 0.0, cur_time = 0.0;
    int i, cops_fet = 0;
    int fd[2];
    pipe(fd);

    int pid = fork();
    if (pid == 0) {
        close(fd[0]);
        close(1);
        dup2(fd[1], 1);
        close(fd[1]);
        execlp("ping", "ping", "-i", xstr(DELAY), "-c", xstr(NUM_COPS), url, NULL);
        exit(0);
    } else if (pid > 0) {
        close(fd[1]);
        char buff[512];
        int n;
        while ((n = read(fd[0], buff, sizeof(buff)-1)) > 0) {
            buff[n] = '\0';
            char *p = strstr(buff, "time=");
            if (p) {
                p += strlen("time=");
                cur_time = 0.0;
                sscanf(p, "%lf", &cur_time);
                printf("%s: %lf\n", url, cur_time);
                if (cur_time > 0.0) {
                    cops_fet++;
                    acum += cur_time;
                }
            }
        }
        close(fd[0]);
        waitpid(-1, NULL, 0);
        *time = acum/cops_fet;
    } else {
        printf("fork() error\n");
        return 0;
    }
    return 1;
}

int main(int argc, char *argv[])
{
    if (argc < 3) {
        printf("Usage:\n\t b7ping serverlist outfile\n");
        return -1;
    }

    FILE *fp_in, *fp_out;
    char *line = NULL;
    size_t len = 0;
    ssize_t read;

    fp_in = fopen(argv[1], "r");
    if (fp_in == NULL) {
        printf("Error opening %s\n", argv[1]);
        return-1;
    }

    fp_out = fopen(argv[2], "w");
    if (fp_in == NULL) {
        printf("Error opening %s\n", argv[2]);
        return-1;
    }

    double time;

    while ((read = getline(&line, &len, fp_in)) != -1) {
        line[strlen(line)-1] = '\0';
        do_ping(line, &time);
        fprintf(fp_out, "%s %f\n", line, time);
        usleep(100*1000);
    }

    fclose(fp_in);
    fclose(fp_out);
    if (line) free(line);
    return 0;
}