build: Merge submodules into repo

src/minarch/libretro-common/file/nbio/nbio_linux.c

@@ -0,0 +1,235 @@
+/* Copyright  (C) 2010-2020 The RetroArch team
+ *
+ * ---------------------------------------------------------------------------------------
+ * The following license statement only applies to this file (nbio_linux.c).
+ * ---------------------------------------------------------------------------------------
+ *
+ * Permission is hereby granted, free of charge,
+ * to any person obtaining a copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <file/nbio.h>
+
+#if defined(__linux__)
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <time.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/syscall.h>
+#include <linux/aio_abi.h>
+
+struct nbio_linux_t
+{
+   void* ptr;
+   aio_context_t ctx;
+   struct iocb cb;
+   size_t len;
+   int fd;
+   bool busy;
+};
+
+/* there's also a Unix AIO thingy, but it's not in glibc
+ * and we don't want more dependencies */
+
+static int io_setup(unsigned nr, aio_context_t * ctxp)
+{
+   return syscall(__NR_io_setup, nr, ctxp);
+}
+
+static int io_destroy(aio_context_t ctx)
+{
+   return syscall(__NR_io_destroy, ctx);
+}
+
+static int io_submit(aio_context_t ctx, long nr, struct iocb ** cbp)
+{
+   return syscall(__NR_io_submit, ctx, nr, cbp);
+}
+
+static int io_cancel(aio_context_t ctx, struct iocb * iocb, struct io_event * result)
+{
+   return syscall(__NR_io_cancel, ctx, iocb, result);
+}
+
+static int io_getevents(aio_context_t ctx, long min_nr, long nr,
+      struct io_event * events, struct timespec * timeout)
+{
+   return syscall(__NR_io_getevents, ctx, min_nr, nr, events, timeout);
+}
+
+static void nbio_begin_op(struct nbio_linux_t* handle, uint16_t op)
+{
+   struct iocb * cbp         = &handle->cb;
+
+   memset(&handle->cb, 0, sizeof(handle->cb));
+
+   handle->cb.aio_fildes     = handle->fd;
+   handle->cb.aio_lio_opcode = op;
+
+   handle->cb.aio_buf        = (uint64_t)(uintptr_t)handle->ptr;
+   handle->cb.aio_offset     = 0;
+   handle->cb.aio_nbytes     = handle->len;
+
+   if (io_submit(handle->ctx, 1, &cbp) != 1)
+      abort();
+
+   handle->busy = true;
+}
+
+static void *nbio_linux_open(const char * filename, unsigned mode)
+{
+   static const int o_flags[]  =   { O_RDONLY, O_RDWR|O_CREAT|O_TRUNC, O_RDWR, O_RDONLY, O_RDWR|O_CREAT|O_TRUNC };
+
+   aio_context_t ctx           = 0;
+   struct nbio_linux_t* handle = NULL;
+   int fd                      = open(filename, o_flags[mode]|O_CLOEXEC, 0644);
+   if (fd < 0)
+      return NULL;
+
+   if (io_setup(128, &ctx) < 0)
+   {
+      close(fd);
+      return NULL;
+   }
+
+   handle       = (struct nbio_linux_t*)malloc(sizeof(struct nbio_linux_t));
+   handle->fd   = fd;
+   handle->ctx  = ctx;
+   handle->len  = lseek(fd, 0, SEEK_END);
+   handle->ptr  = malloc(handle->len);
+   handle->busy = false;
+
+   return handle;
+}
+
+static void nbio_linux_begin_read(void *data)
+{
+   struct nbio_linux_t* handle = (struct nbio_linux_t*)data;
+   if (handle)
+      nbio_begin_op(handle, IOCB_CMD_PREAD);
+}
+
+static void nbio_linux_begin_write(void *data)
+{
+   struct nbio_linux_t* handle = (struct nbio_linux_t*)data;
+   if (handle)
+      nbio_begin_op(handle, IOCB_CMD_PWRITE);
+}
+
+static bool nbio_linux_iterate(void *data)
+{
+   struct nbio_linux_t* handle = (struct nbio_linux_t*)data;
+   if (!handle)
+      return false;
+   if (handle->busy)
+   {
+      struct io_event ev;
+      if (io_getevents(handle->ctx, 0, 1, &ev, NULL) == 1)
+         handle->busy = false;
+   }
+   return !handle->busy;
+}
+
+static void nbio_linux_resize(void *data, size_t len)
+{
+   struct nbio_linux_t* handle = (struct nbio_linux_t*)data;
+   if (!handle)
+      return;
+
+   /* This works perfectly fine if this check is removed, but it
+    * won't work on other nbio implementations */
+   /* therefore, it's blocked so nobody accidentally relies on it */
+   if (len < handle->len)
+      abort();
+
+   if (ftruncate(handle->fd, len) != 0)
+      abort(); /* this one returns void and I can't find any other way
+                  for it to report failure */
+
+   handle->ptr = realloc(handle->ptr, len);
+   handle->len = len;
+}
+
+static void *nbio_linux_get_ptr(void *data, size_t* len)
+{
+   struct nbio_linux_t* handle = (struct nbio_linux_t*)data;
+   if (!handle)
+      return NULL;
+   if (len)
+      *len = handle->len;
+   if (!handle->busy)
+      return handle->ptr;
+   return NULL;
+}
+
+static void nbio_linux_cancel(void *data)
+{
+   struct nbio_linux_t* handle = (struct nbio_linux_t*)data;
+   if (!handle)
+      return;
+
+   if (handle->busy)
+   {
+      struct io_event ev;
+      io_cancel(handle->ctx, &handle->cb, &ev);
+      handle->busy = false;
+   }
+}
+
+static void nbio_linux_free(void *data)
+{
+   struct nbio_linux_t* handle = (struct nbio_linux_t*)data;
+   if (!handle)
+      return;
+
+   io_destroy(handle->ctx);
+   close(handle->fd);
+   free(handle->ptr);
+   free(handle);
+}
+
+nbio_intf_t nbio_linux = {
+   nbio_linux_open,
+   nbio_linux_begin_read,
+   nbio_linux_begin_write,
+   nbio_linux_iterate,
+   nbio_linux_resize,
+   nbio_linux_get_ptr,
+   nbio_linux_cancel,
+   nbio_linux_free,
+   "nbio_linux",
+};
+#else
+nbio_intf_t nbio_linux = {
+   NULL,
+   NULL,
+   NULL,
+   NULL,
+   NULL,
+   NULL,
+   NULL,
+   NULL,
+   "nbio_linux",
+};
+
+#endif