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/* SPDX-License-Identifier: MIT */
#define _DEFAULT_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include "liburing/compat.h"
#include "liburing/io_uring.h"
#include "liburing.h"
#include "syscall.h"
static void io_uring_unmap_rings(struct io_uring_sq *sq, struct io_uring_cq *cq)
{
munmap(sq->ring_ptr, sq->ring_sz);
if (cq->ring_ptr && cq->ring_ptr != sq->ring_ptr)
munmap(cq->ring_ptr, cq->ring_sz);
}
static int io_uring_mmap(int fd, struct io_uring_params *p,
struct io_uring_sq *sq, struct io_uring_cq *cq)
{
size_t size;
int ret;
sq->ring_sz = p->sq_off.array + p->sq_entries * sizeof(unsigned);
cq->ring_sz = p->cq_off.cqes + p->cq_entries * sizeof(struct io_uring_cqe);
if (p->features & IORING_FEAT_SINGLE_MMAP) {
if (cq->ring_sz > sq->ring_sz)
sq->ring_sz = cq->ring_sz;
cq->ring_sz = sq->ring_sz;
}
sq->ring_ptr = mmap(0, sq->ring_sz, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_SQ_RING);
if (sq->ring_ptr == MAP_FAILED)
return -errno;
if (p->features & IORING_FEAT_SINGLE_MMAP) {
cq->ring_ptr = sq->ring_ptr;
} else {
cq->ring_ptr = mmap(0, cq->ring_sz, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_CQ_RING);
if (cq->ring_ptr == MAP_FAILED) {
cq->ring_ptr = NULL;
ret = -errno;
goto err;
}
}
sq->khead = sq->ring_ptr + p->sq_off.head;
sq->ktail = sq->ring_ptr + p->sq_off.tail;
sq->kring_mask = sq->ring_ptr + p->sq_off.ring_mask;
sq->kring_entries = sq->ring_ptr + p->sq_off.ring_entries;
sq->kflags = sq->ring_ptr + p->sq_off.flags;
sq->kdropped = sq->ring_ptr + p->sq_off.dropped;
sq->array = sq->ring_ptr + p->sq_off.array;
size = p->sq_entries * sizeof(struct io_uring_sqe);
sq->sqes = mmap(0, size, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_POPULATE, fd,
IORING_OFF_SQES);
if (sq->sqes == MAP_FAILED) {
ret = -errno;
err:
io_uring_unmap_rings(sq, cq);
return ret;
}
cq->khead = cq->ring_ptr + p->cq_off.head;
cq->ktail = cq->ring_ptr + p->cq_off.tail;
cq->kring_mask = cq->ring_ptr + p->cq_off.ring_mask;
cq->kring_entries = cq->ring_ptr + p->cq_off.ring_entries;
cq->koverflow = cq->ring_ptr + p->cq_off.overflow;
cq->cqes = cq->ring_ptr + p->cq_off.cqes;
if (p->cq_off.flags)
cq->kflags = cq->ring_ptr + p->cq_off.flags;
return 0;
}
/*
* For users that want to specify sq_thread_cpu or sq_thread_idle, this
* interface is a convenient helper for mmap()ing the rings.
* Returns -errno on error, or zero on success. On success, 'ring'
* contains the necessary information to read/write to the rings.
*/
int io_uring_queue_mmap(int fd, struct io_uring_params *p, struct io_uring *ring)
{
int ret;
memset(ring, 0, sizeof(*ring));
ret = io_uring_mmap(fd, p, &ring->sq, &ring->cq);
if (!ret) {
ring->flags = p->flags;
ring->ring_fd = fd;
}
return ret;
}
/*
* Ensure that the mmap'ed rings aren't available to a child after a fork(2).
* This uses madvise(..., MADV_DONTFORK) on the mmap'ed ranges.
*/
int io_uring_ring_dontfork(struct io_uring *ring)
{
size_t len;
int ret;
if (!ring->sq.ring_ptr || !ring->sq.sqes || !ring->cq.ring_ptr)
return -EINVAL;
len = *ring->sq.kring_entries * sizeof(struct io_uring_sqe);
ret = madvise(ring->sq.sqes, len, MADV_DONTFORK);
if (ret == -1)
return -errno;
len = ring->sq.ring_sz;
ret = madvise(ring->sq.ring_ptr, len, MADV_DONTFORK);
if (ret == -1)
return -errno;
if (ring->cq.ring_ptr != ring->sq.ring_ptr) {
len = ring->cq.ring_sz;
ret = madvise(ring->cq.ring_ptr, len, MADV_DONTFORK);
if (ret == -1)
return -errno;
}
return 0;
}
int io_uring_queue_init_params(unsigned entries, struct io_uring *ring,
struct io_uring_params *p)
{
int fd, ret;
fd = __sys_io_uring_setup(entries, p);
if (fd < 0)
return -errno;
ret = io_uring_queue_mmap(fd, p, ring);
if (ret) {
close(fd);
return ret;
}
ring->features = p->features;
return 0;
}
/*
* Returns -errno on error, or zero on success. On success, 'ring'
* contains the necessary information to read/write to the rings.
*/
int io_uring_queue_init(unsigned entries, struct io_uring *ring, unsigned flags)
{
struct io_uring_params p;
memset(&p, 0, sizeof(p));
p.flags = flags;
return io_uring_queue_init_params(entries, ring, &p);
}
void io_uring_queue_exit(struct io_uring *ring)
{
struct io_uring_sq *sq = &ring->sq;
struct io_uring_cq *cq = &ring->cq;
munmap(sq->sqes, *sq->kring_entries * sizeof(struct io_uring_sqe));
io_uring_unmap_rings(sq, cq);
close(ring->ring_fd);
}
struct io_uring_probe *io_uring_get_probe_ring(struct io_uring *ring)
{
struct io_uring_probe *probe;
int r;
size_t len = sizeof(*probe) + 256 * sizeof(struct io_uring_probe_op);
probe = malloc(len);
memset(probe, 0, len);
r = io_uring_register_probe(ring, probe, 256);
if (r < 0)
goto fail;
return probe;
fail:
free(probe);
return NULL;
}
struct io_uring_probe *io_uring_get_probe(void)
{
struct io_uring ring;
struct io_uring_probe* probe = NULL;
int r = io_uring_queue_init(2, &ring, 0);
if (r < 0)
return NULL;
probe = io_uring_get_probe_ring(&ring);
io_uring_queue_exit(&ring);
return probe;
}
void io_uring_free_probe(struct io_uring_probe *probe)
{
free(probe);
}
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