fix(storage/vfs_console): stop new console opens from overwriting existing fds

components/esp_vfs_console/vfs_console.c

@@ -15,8 +15,8 @@
 #include "esp_vfs_console.h"
 #include "sdkconfig.h"
 #include "esp_private/startup_internal.h"
-#include "esp_vfs_null.h"
 #include "esp_private/nullfs.h"
+#include <sys/errno.h>
 
 #define STRINGIFY(s) STRINGIFY2(s)
 #define STRINGIFY2(s) #s
@@ -45,8 +45,18 @@ const static esp_vfs_fs_ops_t *primary_vfs = NULL;
 
 static vfs_console_context_t vfs_console = {0};
 
+static size_t s_open_count = 0;
+
 int console_open(const char * path, int flags, int mode)
 {
+    if (s_open_count > 0) {
+        // Underlying fd is already open, so just increment the open count
+        // and return the same fd
+
+        s_open_count++;
+        return 0;
+    }
+
 // Primary port open
 #if CONFIG_ESP_CONSOLE_UART
     vfs_console.fd_primary = open("/dev/uart/"STRINGIFY(CONFIG_ESP_CONSOLE_UART_NUM), flags, mode);
@@ -62,6 +72,8 @@ int console_open(const char * path, int flags, int mode)
 #if CONFIG_ESP_CONSOLE_SECONDARY_USB_SERIAL_JTAG
     vfs_console.fd_secondary = open("/dev/secondary", flags, mode);
 #endif
+
+    s_open_count++;
     return 0;
 }
 
@@ -82,6 +94,18 @@ int console_fstat(int fd, struct stat * st)
 
 int console_close(int fd)
 {
+    if (s_open_count == 0) {
+        errno = EBADF;
+        return -1;
+    }
+
+    s_open_count--;
+
+    // We don't actually close the underlying fd until the open count reaches 0
+    if (s_open_count > 0) {
+        return 0;
+    }
+
     // All function calls are to primary, except from write and close, which will be forwarded to both primary and secondary.
     close(vfs_console.fd_primary);
 #if CONFIG_ESP_CONSOLE_SECONDARY_USB_SERIAL_JTAG