From 35ea136d5a65318cdb9c1eca57f9c69ba32f49f1 Mon Sep 17 00:00:00 2001
From: Ivan Grokhotkov <ivan@espressif.com>
Date: Thu, 1 Dec 2022 13:55:12 +0100
Subject: [PATCH] newlib: implement fsync for the case of
 CONFIG_VFS_SUPPORT_IO=0

This feature allows calling fsync even if the vfs component is not
used.
The second part of the commit adds an fsync call in the panic test app
enabling it to be used over usb-serial-jtag.
---
 components/newlib/syscalls.c                   | 18 ++++++++++++++++++
 tools/test_apps/system/panic/main/test_panic.c |  1 +
 2 files changed, 19 insertions(+)

diff --git a/components/newlib/syscalls.c b/components/newlib/syscalls.c
index 06e342407c..e5e1f24a0b 100644
--- a/components/newlib/syscalls.c
+++ b/components/newlib/syscalls.c
@@ -73,6 +73,22 @@ static ssize_t _fstat_r_console(struct _reent *r, int fd, struct stat * st)
     return -1;
 }
 
+static int _fsync_console(int fd)
+{
+    if (fd == STDOUT_FILENO || fd == STDERR_FILENO) {
+#ifdef CONFIG_ESP_CONSOLE_UART
+        esp_rom_uart_flush_tx(CONFIG_ESP_CONSOLE_UART_NUM);
+#elif defined(CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG)
+        esp_rom_uart_flush_tx(CONFIG_ESP_ROM_USB_SERIAL_DEVICE_NUM);
+#elif defined(CONFIG_ESP_CONSOLE_USB_CDC)
+        esp_rom_uart_flush_tx(CONFIG_ESP_ROM_USB_OTG_NUM);
+#endif
+        return 0;
+    }
+    errno = EBADF;
+    return -1;
+}
+
 
 /* The following weak definitions of syscalls will be used unless
  * another definition is provided. That definition may come from
@@ -84,6 +100,8 @@ ssize_t _write_r(struct _reent *r, int fd, const void * data, size_t size)
     __attribute__((weak,alias("_write_r_console")));
 int _fstat_r (struct _reent *r, int fd, struct stat *st)
     __attribute__((weak,alias("_fstat_r_console")));
+int fsync(int fd)
+    __attribute__((weak,alias("_fsync_console")));
 
 
 /* The aliases below are to "syscall_not_implemented", which
diff --git a/tools/test_apps/system/panic/main/test_panic.c b/tools/test_apps/system/panic/main/test_panic.c
index 10d9f9e5a8..19f200ad76 100644
--- a/tools/test_apps/system/panic/main/test_panic.c
+++ b/tools/test_apps/system/panic/main/test_panic.c
@@ -27,6 +27,7 @@ void die(const char* msg)
 {
     printf("Test error: %s\n\n", msg);
     fflush(stdout);
+    fsync(fileno(stdout));
     usleep(1000);
     /* Don't use abort here as it would enter the panic handler */
     esp_restart_noos();