crappy grayscale lemonbar manager

barm.c

/*
 * lemonbar manager
 * by eeeeeta
 */
#define UPDATE_INTERVAL 10

#define GRAY "%{F#808080}"
#define WHITE "%{F#FFFFFF}"
#include <stdio.h>
#include <time.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
FILE *barfp;

char *callocr(int sz) {
    char *ret;
    if ((ret = calloc(sz, 1)) == NULL) {
        perror("calloc failed");
        pclose(barfp);
        exit(EXIT_FAILURE);
    }
    return ret;
}
char *exec(char *cmd) {
    FILE *fp;
    char *state = callocr(175);
    if ((fp = popen(cmd, "r")) == NULL) {
        printf("popen failed\n");
        if (errno != 0) perror("popen() failed");
        strncpy(state, "popen() failed!", 100);
        return state;
    }
    if ((errno = 0) == 0 && fgets(state, 175, fp) == NULL && errno != 0) {
        printf("fgets failed\n");
        strncpy(state, "fgets() failed!", 100);
        return state;
    }
    if (pclose(fp) == -1) {
        printf("warn: pclose failed\n");
        perror("pclose");
    }
    int len = strlen(state);
    if (state[len-1] == '\n') state[len-1] = '\0';
    return state;
}
char *get_load() {
    double loadavg[3];
    char *ret = callocr(50);
    if ((getloadavg(loadavg, 3)) == -1) {
        strncpy(ret, "err", 14);
        return ret;
    }
    snprintf(ret, 50, "%sload%s %1.2f", GRAY, WHITE, loadavg[0]);
    return ret;
}
char *get_vol() {
    char *vol = exec("pulseaudio-ctl full-status");
    if (strcmp(vol, "failed") == 0) return vol;
    char *ret = callocr(100);
    char *rvol = strtok(vol, " ");
    char *mute = strtok(NULL, " ");
    snprintf(ret, 100, "%svol %s%s%% %smuted %s%s", GRAY, WHITE, rvol, GRAY, WHITE, mute);
    free(vol);
    return ret;
}
char *get_time() {
    char *ret = callocr(50);
    time_t rawtime;
    struct tm * timeinfo;
    time(&rawtime);
    timeinfo = localtime(&rawtime);
    strftime(ret, 50, "%I:%M", timeinfo);
    return ret;
}
void bar_upd(int sig) {
   char *mpc_state = exec("mpc current -f \"%{F##808080}title%{F##FFFFFF} %title% %{F##808080}artist %{F##FFFFFF}%artist% %{F##808080}album %{F##FFFFFF}%album%\"");
   char *load = get_load();
   char *time = get_time();
   char *vol = get_vol();
   char *win = exec("bspc query -D -d focused");
   char *login;
   if ((login = getlogin()) == NULL) login = "getlogin() failed :(";
   char barstr[1000];
   snprintf(barstr, 500, "%%{l}%sdesktop %s%s%%{c}%s%%{r}%s %s %suser %s%s %stime %s%s\n", GRAY, WHITE, win, mpc_state, vol, load, GRAY, WHITE, login, GRAY, WHITE, time);
   fputs(barstr, barfp);
   fflush(barfp);
   free(mpc_state);
   free(win);
   free(vol);
   free(time);
   free(load);
}
int main(int argc, char *argv[]) {
    int upd = UPDATE_INTERVAL;
    printf("eeeeeta's lemonbar manager\n");
    if (argc > 1) {
        upd = strtol(argv[1], NULL, 10);
    }
    printf("spawning lemonbar...");
    if ((barfp = popen("lemonbar -g 1890x20+15+10 -f Inconsolata", "w")) == NULL) {
        printf("failed\n");
        if (errno != 0) perror("popen() failed");
    }
    printf("done :D\n");
    struct sigaction sa;
    sa.sa_handler = bar_upd;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART;
    if (sigaction(SIGUSR1, &sa, NULL) == -1) {
        perror("sigaction failed");
        exit(EXIT_FAILURE);
    }
    bar_upd(SIGUSR1);
    printf("updating every %d seconds, or when I get a SIGUSR1\n", upd);
    while (1) {
        if (sleep(upd) == 0) bar_upd(SIGUSR1);
    }
}