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#include <assert.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/xattr.h>
#include <unistd.h>
#include "helpers.h"
#include "liburing.h"
#define BUFFER_SIZE 512
#define LIST_INIT(name) { &(name), &(name) }
#define CONTAINER_OF(ptr, type, member) ( \
{ \
const typeof(((type *)0)->member) *__ptr = (ptr); \
(type *)((char *)__ptr - (intptr_t)(&((type *)0)->member)); \
})
struct list {
struct list *next;
struct list *prev;
};
struct dir {
struct list list;
int ret;
struct dir *parent;
int fd;
uint64_t off;
uint8_t buf[BUFFER_SIZE];
char name[0];
};
struct linux_dirent64 {
int64_t d_ino; /* 64-bit inode number */
int64_t d_off; /* 64-bit offset to next structure */
unsigned short d_reclen; /* Size of this dirent */
unsigned char d_type; /* File type */
char d_name[]; /* Filename (null-terminated) */
};
/* Define global variables. */
static struct io_uring ring;
static struct list active = LIST_INIT(active);
static int sqes_in_flight = 0;
static int num_dir_entries = 0;
/* Forward declarations. */
static void drain_cqes(void);
static void schedule_readdir(struct dir *dir);
/* List helper functions. */
static inline void
list_add_tail(struct list *l, struct list *head)
{
l->next = head;
l->prev = head->prev;
head->prev->next = l;
head->prev = l;
}
static inline void list_del(struct list *l)
{
l->prev->next = l->next;
l->next->prev = l->prev;
l->prev = NULL;
l->next = NULL;
}
static inline int is_list_empty(const struct list *l)
{
return l->next == l;
}
static struct io_uring_sqe *get_sqe(void)
{
struct io_uring_sqe *sqe;
sqe = io_uring_get_sqe(&ring);
while (sqe == NULL) {
drain_cqes();
int ret = io_uring_submit(&ring);
if (ret < 0 && errno != EBUSY) {
perror("io_uring_submit");
exit(EXIT_FAILURE);
}
sqe = io_uring_get_sqe(&ring);
}
sqes_in_flight++;
return sqe;
}
static void drain_cqes(void)
{
int count;
uint32_t head;
struct io_uring_cqe *cqe;
count = 0;
io_uring_for_each_cqe (&ring, head, cqe) {
struct dir *dir;
dir = io_uring_cqe_get_data(cqe);
list_add_tail(&dir->list, &active);
dir->ret = cqe->res;
count++;
}
sqes_in_flight -= count;
io_uring_cq_advance(&ring, count);
}
static void schedule_opendir(struct dir *parent, const char *name)
{
int len = strlen(name);
struct dir *dir;
struct io_uring_sqe *sqe;
dir = malloc(sizeof(*dir) + len + 1);
if (dir == NULL) {
fprintf(stderr, "out of memory\n");
exit(EXIT_FAILURE);
}
dir->parent = parent;
dir->fd = -1;
memcpy(dir->name, name, len);
dir->name[len] = 0;
sqe = get_sqe();
io_uring_prep_openat(sqe,
(parent != NULL) ? parent->fd : AT_FDCWD,
dir->name,
O_DIRECTORY,
0);
io_uring_sqe_set_data(sqe, dir);
}
static void opendir_completion(struct dir *dir, int ret)
{
if (ret < 0) {
fprintf(stderr, "error opening ");
fprintf(stderr, ": %s\n", strerror(-ret));
return;
}
dir->fd = ret;
dir->off = 0;
schedule_readdir(dir);
}
static void schedule_readdir(struct dir *dir)
{
struct io_uring_sqe *sqe;
sqe = get_sqe();
io_uring_prep_getdents(sqe, dir->fd, dir->buf, sizeof(dir->buf), dir->off);
io_uring_sqe_set_data(sqe, dir);
}
static void readdir_completion(struct dir *dir, int ret)
{
uint8_t *bufp;
uint8_t *end;
if (ret < 0) {
fprintf(stderr, "error reading ");
fprintf(stderr, ": %s (%d)\n", strerror(-ret), ret);
return;
}
if (ret == 0) {
free(dir);
return;
}
bufp = dir->buf;
end = bufp + ret;
while (bufp < end) {
struct linux_dirent64 *dent;
dent = (struct linux_dirent64 *)bufp;
if (strcmp(dent->d_name, ".") && strcmp(dent->d_name, "..")) {
if (dent->d_type == DT_DIR)
schedule_opendir(dir, dent->d_name);
}
dir->off = dent->d_off;
bufp += dent->d_reclen;
++num_dir_entries;
}
schedule_readdir(dir);
}
int main(int argc, char *argv[])
{
struct rlimit rlim;
/* Increase number of files rlimit to 1M. */
if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
perror("getrlimit");
return 1;
}
if (geteuid() == 0 && rlim.rlim_max < 1048576)
rlim.rlim_max = 1048576;
if (rlim.rlim_cur < rlim.rlim_max) {
rlim.rlim_cur = rlim.rlim_max;
setrlimit(RLIMIT_NOFILE, &rlim);
}
if (io_uring_queue_init(256, &ring, 0) < 0) {
perror("io_uring_queue_init");
return 1;
}
/* Submit and handle requests. */
schedule_opendir(NULL, ".");
while (sqes_in_flight) {
int ret = io_uring_submit_and_wait(&ring, 1);
if (ret < 0 && errno != EBUSY) {
perror("io_uring_submit_and_wait");
return 1;
}
drain_cqes();
while (!is_list_empty(&active)) {
struct dir *dir;
dir = CONTAINER_OF(active.next, struct dir, list);
list_del(&dir->list);
if (dir->fd == -1)
opendir_completion(dir, dir->ret);
else
readdir_completion(dir, dir->ret);
}
}
io_uring_queue_exit(&ring);
return num_dir_entries < 50;
}
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