Squashed 'lib/lwip/lwip/' content from commit 0a0452b2c39b

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diff --git a/contrib/examples/httpd/fs_example/fs_example.c b/contrib/examples/httpd/fs_example/fs_example.c
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+/**
+ * @file
+ * HTTPD custom file system example
+ *
+ * This file demonstrates how to add support for an external file system to httpd.
+ * It provides access to the specified root directory and uses stdio.h file functions
+ * to read files.
+ *
+ * ATTENTION: This implementation is *not* secure: no checks are added to ensure
+ * files are only read below the specified root directory!
+ */
+ 
+ /*
+ * Copyright (c) 2017 Simon Goldschmidt
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Simon Goldschmidt <goldsimon@gmx.de>
+ *
+ */
+
+#include "lwip/opt.h"
+#include "fs_example.h"
+
+#include "lwip/apps/fs.h"
+#include "lwip/def.h"
+#include "lwip/mem.h"
+
+#include <stdio.h>
+#include <string.h>
+
+/** define LWIP_HTTPD_EXAMPLE_CUSTOMFILES to 1 to enable this file system */
+#ifndef LWIP_HTTPD_EXAMPLE_CUSTOMFILES
+#define LWIP_HTTPD_EXAMPLE_CUSTOMFILES 0
+#endif
+
+/** define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED to 1 to delay open and read
+ * as if e.g. reading from external SPI flash */
+#ifndef LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
+#define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED 1
+#endif
+
+/** define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ to the number of bytes
+ * to read to emulate limited transfer buffers and don't read whole files in
+ * one chunk.
+ * WARNING: lowering this slows down the connection!
+ */
+#ifndef LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ
+#define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ 0
+#endif
+
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES
+
+#if !LWIP_HTTPD_CUSTOM_FILES
+#error This needs LWIP_HTTPD_CUSTOM_FILES
+#endif
+#if !LWIP_HTTPD_DYNAMIC_HEADERS
+#error This needs LWIP_HTTPD_DYNAMIC_HEADERS
+#endif
+#if !LWIP_HTTPD_DYNAMIC_FILE_READ
+#error This wants to demonstrate read-after-open, so LWIP_HTTPD_DYNAMIC_FILE_READ is required!
+#endif
+#if !LWIP_HTTPD_FS_ASYNC_READ
+#error This needs LWIP_HTTPD_FS_ASYNC_READ
+#endif
+#if !LWIP_HTTPD_FILE_EXTENSION
+#error This needs LWIP_HTTPD_FILE_EXTENSION
+#endif
+
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
+#include "lwip/tcpip.h"
+#endif
+
+struct fs_custom_data {
+  FILE *f;
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
+  int delay_read;
+  fs_wait_cb callback_fn;
+  void *callback_arg;
+#endif
+};
+
+const char* fs_ex_root_dir;
+
+void
+fs_ex_init(const char *httpd_root_dir)
+{
+  fs_ex_root_dir = strdup(httpd_root_dir);
+}
+
+#if LWIP_HTTPD_CUSTOM_FILES
+int
+fs_open_custom(struct fs_file *file, const char *name)
+{
+  char full_filename[256];
+  FILE *f;
+
+  snprintf(full_filename, 255, "%s%s", fs_ex_root_dir, name);
+  full_filename[255] = 0;
+
+  f = fopen(full_filename, "rb");
+  if (f != NULL) {
+    if (!fseek(f, 0, SEEK_END)) {
+      int len = (int)ftell(f);
+      if(!fseek(f, 0, SEEK_SET)) {
+        struct fs_custom_data *data = (struct fs_custom_data *)mem_malloc(sizeof(struct fs_custom_data));
+        LWIP_ASSERT("out of memory?", data != NULL);
+        memset(file, 0, sizeof(struct fs_file));
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
+        file->len = 0; /* read size delayed */
+        data->delay_read = 3;
+        LWIP_UNUSED_ARG(len);
+#else
+        file->len = len;
+#endif
+        file->flags = FS_FILE_FLAGS_HEADER_PERSISTENT;
+        data->f = f;
+        file->pextension = data;
+        return 1;
+      }
+    }
+    fclose(f);
+  }
+  return 0;
+}
+
+void
+fs_close_custom(struct fs_file *file)
+{
+  if (file && file->pextension) {
+    struct fs_custom_data *data = (struct fs_custom_data *)file->pextension;
+    if (data->f != NULL) {
+      fclose(data->f);
+      data->f = NULL;
+    }
+    mem_free(data);
+  }
+}
+
+#if LWIP_HTTPD_FS_ASYNC_READ
+u8_t
+fs_canread_custom(struct fs_file *file)
+{
+  /* This function is only necessary for asynchronous I/O:
+     If reading would block, return 0 and implement fs_wait_read_custom() to call the
+     supplied callback if reading works. */
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
+  struct fs_custom_data *data;
+  LWIP_ASSERT("file != NULL", file != NULL);
+  data = (struct fs_custom_data *)file->pextension;
+  if (data == NULL) {
+    /* file transfer has been completed already */
+    LWIP_ASSERT("transfer complete", file->index == file->len);
+    return 1;
+  }
+  LWIP_ASSERT("data != NULL", data != NULL);
+  /* This just simulates a simple delay. This delay would normally come e.g. from SPI transfer */
+  if (data->delay_read == 3) {
+    /* delayed file size mode */
+    data->delay_read = 1;
+    LWIP_ASSERT("", file->len == 0);
+    if (!fseek(data->f, 0, SEEK_END)) {
+      int len = (int)ftell(data->f);
+      if(!fseek(data->f, 0, SEEK_SET)) {
+        file->len = len; /* read size delayed */
+        data->delay_read = 1;
+        return 0;
+      }
+    }
+    /* if we come here, something is wrong with the file */
+    LWIP_ASSERT("file error", 0);
+  }
+  if (data->delay_read == 1) {
+    /* tell read function to delay further */
+  }
+#endif
+  LWIP_UNUSED_ARG(file);
+  return 1;
+}
+
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
+static void
+fs_example_read_cb(void *arg)
+{
+  struct fs_custom_data *data = (struct fs_custom_data *)arg;
+  fs_wait_cb callback_fn = data->callback_fn;
+  void *callback_arg = data->callback_arg;
+  data->callback_fn = NULL;
+  data->callback_arg = NULL;
+
+  LWIP_ASSERT("no callback_fn", callback_fn != NULL);
+
+  callback_fn(callback_arg);
+}
+#endif
+
+u8_t
+fs_wait_read_custom(struct fs_file *file, fs_wait_cb callback_fn, void *callback_arg)
+{
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
+  err_t err;
+  struct fs_custom_data *data = (struct fs_custom_data *)file->pextension;
+  LWIP_ASSERT("data not set", data != NULL);
+  data->callback_fn = callback_fn;
+  data->callback_arg = callback_arg;
+  err = tcpip_try_callback(fs_example_read_cb, data);
+  LWIP_ASSERT("out of queue elements?", err == ERR_OK);
+  LWIP_UNUSED_ARG(err);
+#else
+  LWIP_ASSERT("not implemented in this example configuration", 0);
+#endif
+  LWIP_UNUSED_ARG(file);
+  LWIP_UNUSED_ARG(callback_fn);
+  LWIP_UNUSED_ARG(callback_arg);
+  /* Return
+     - 0 if ready to read (at least one byte)
+     - 1 if reading should be delayed (call 'tcpip_callback(callback_fn, callback_arg)' when ready) */
+  return 1;
+}
+
+int
+fs_read_async_custom(struct fs_file *file, char *buffer, int count, fs_wait_cb callback_fn, void *callback_arg)
+{
+  struct fs_custom_data *data = (struct fs_custom_data *)file->pextension;
+  FILE *f;
+  int len;
+  int read_count = count;
+  LWIP_ASSERT("data not set", data != NULL);
+
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
+  /* This just simulates a delay. This delay would normally come e.g. from SPI transfer */
+  LWIP_ASSERT("invalid state", data->delay_read >= 0 && data->delay_read <= 2);
+  if (data->delay_read == 2) {
+    /* no delay next time */
+    data->delay_read = 0;
+    return FS_READ_DELAYED;
+  } else if (data->delay_read == 1) {
+    err_t err;
+    /* execute requested delay */
+    data->delay_read = 2;
+    LWIP_ASSERT("duplicate callback request", data->callback_fn == NULL);
+    data->callback_fn = callback_fn;
+    data->callback_arg = callback_arg;
+    err = tcpip_try_callback(fs_example_read_cb, data);
+    LWIP_ASSERT("out of queue elements?", err == ERR_OK);
+    LWIP_UNUSED_ARG(err);
+    return FS_READ_DELAYED;
+  }
+  /* execute this read but delay the next one */
+  data->delay_read = 1;
+#endif
+
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ
+  read_count = LWIP_MIN(read_count, LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ);
+#endif
+
+  f = data->f;
+  len = (int)fread(buffer, 1, read_count, f);
+
+  LWIP_UNUSED_ARG(callback_fn);
+  LWIP_UNUSED_ARG(callback_arg);
+
+  file->index += len;
+
+  /* Return
+     - FS_READ_EOF if all bytes have been read
+     - FS_READ_DELAYED if reading is delayed (call 'tcpip_callback(callback_fn, callback_arg)' when done) */
+  if (len == 0) {
+    /* all bytes read already */
+    return FS_READ_EOF;
+  }
+  return len;
+}
+
+#else /* LWIP_HTTPD_FS_ASYNC_READ */
+int
+fs_read_custom(struct fs_file *file, char *buffer, int count)
+{
+  struct fs_custom_data *data = (struct fs_custom_data *)file->pextension;
+  FILE *f;
+  int len;
+  int read_count = count;
+  LWIP_ASSERT("data not set", data != NULL);
+
+#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ
+  read_count = LWIP_MIN(read_count, LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ);
+#endif
+
+  f = data->f;
+  len = (int)fread(buffer, 1, read_count, f);
+
+  file->index += len;
+
+  /* Return FS_READ_EOF if all bytes have been read */
+  return len;
+}
+
+#endif /* LWIP_HTTPD_FS_ASYNC_READ */
+#endif /* LWIP_HTTPD_CUSTOM_FILES */
+
+#endif /* LWIP_HTTPD_EXAMPLE_CUSTOMFILES */