#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <dirent.h>
#include <unistd.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>

static int verbose = 1;
static unsigned int dirc = 0, filec = 0, errc = 0;
static time_t last_ts;

/* RSS in kilobytes */
static unsigned int
get_rss()
{
    char buf[1024];
    int bytes, i, nf = 1;
    int fd = open("/proc/self/stat", O_RDONLY);
    if (fd == -1)
        return 0;
    bytes = read(fd, buf, sizeof(buf) - 1);
    close(fd);
    if (bytes <= 0)
        return 0;
    buf[bytes] = 0;
    for (i = 0; i < bytes; i++) {
        switch (buf[i]) {
        case 0x20:
            nf++;
            if (nf == 24) /* RSS */
                return atoi(buf + i) << 2;
            break;
        case 0:
            return 0;
        }
    }
    return 0;
}

static void
show_progress()
{
    time_t now = time(NULL);
    if (now != last_ts) {
        last_ts = now;
        printf("\r%u items removed, %u errors, rss = %.2fM", dirc + filec, errc, get_rss() / 1024.0);
        fflush(stdout);
    }
}

static void
dir_removed()
{
    dirc++;
    if (verbose)
        show_progress();
}

static void
file_removed()
{
    filec++;
    if (verbose)
        show_progress();
}

static void
error()
{
    errc++;
    if (verbose)
        show_progress();
}

static int
cleardir(int rootfd, const char *relpath)
{
    DIR *dir;
    struct dirent *e;
    struct {
        struct dirent e;
        char path[256];
    } buf;
    int dfd = openat(rootfd, relpath, O_RDONLY | O_DIRECTORY);
    if (dfd == -1) {
        perror("openat");
        return -1;
    }

    dir = fdopendir(dfd);
    if (dir == NULL) {
        perror("fdopendir");
        close(dfd);
        return -1;
    }

    while (readdir_r(dir, &buf.e, &e) == 0) {
        if (e == NULL)
            break;
        if (strcmp(e->d_name, ".") == 0
                || strcmp(e->d_name, "..") == 0)
            continue;
        if (unlinkat(dfd, e->d_name, 0) == 0) {
            file_removed();
            continue;
        }
        switch (errno) {
        case EISDIR:
            /* try to unlink possible empty directory */
            if (unlinkat(dfd, e->d_name, AT_REMOVEDIR) == 0) {
                dir_removed();
            } else if (errno == ENOTEMPTY && cleardir(dfd, e->d_name) == 0) {
                if (unlinkat(dfd, e->d_name, AT_REMOVEDIR) == 0)
                    dir_removed();
                else
                    error();
            }
            break;
        default:
            perror("unlinkat");
            error();
        }
    }

    closedir(dir);
    return 0;
}

int main(int argc, char *argv[])
{
    int i;
    last_ts = time(NULL);
    for (i = 1; i < argc; i++)
        cleardir(AT_FDCWD, argv[i]);
    last_ts = 0;
    show_progress();
    puts("");
    return 0;
}