From 3ff51d108b39bd34e8c6caab20ff8412d9c30304 Mon Sep 17 00:00:00 2001
From: Xiang Xiao <xiaoxiang@xiaomi.com>
Date: Mon, 4 Sep 2023 02:35:38 +0800
Subject: [PATCH] system/cu: Merge infd and outfd into devfd

to avoid opening the same device twice since
some special device can't work in this case

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
---
 system/cu/cu.h      |  3 +--
 system/cu/cu_main.c | 48 ++++++++++++++++-----------------------------
 2 files changed, 18 insertions(+), 33 deletions(-)

diff --git a/system/cu/cu.h b/system/cu/cu.h
index fa7d72c7d..9f69104bc 100644
--- a/system/cu/cu.h
+++ b/system/cu/cu.h
@@ -71,8 +71,7 @@
 
 struct cu_globals_s
 {
-  int infd;              /* Incoming data from serial port */
-  int outfd;             /* Outgoing data to serial port */
+  int devfd;             /* I/O data to serial port */
   int stdfd;             /* I/O data to standard console */
   struct termios devtio; /* Original serial port setting */
   struct termios stdtio; /* Original standard console setting */
diff --git a/system/cu/cu_main.c b/system/cu/cu_main.c
index 6252667ca..ea0df68aa 100644
--- a/system/cu/cu_main.c
+++ b/system/cu/cu_main.c
@@ -104,7 +104,7 @@ static FAR void *cu_listener(FAR void *parameter)
       int rc;
       char ch;
 
-      rc = read(cu->infd, &ch, 1);
+      rc = read(cu->devfd, &ch, 1);
       if (rc <= 0)
         {
           break;
@@ -176,7 +176,7 @@ static int set_termios(FAR struct cu_globals_s *cu, int nocrlf)
       tio.c_oflag |= ONLCR;
     }
 
-  ret = tcsetattr(cu->outfd, TCSANOW, &tio);
+  ret = tcsetattr(cu->devfd, TCSANOW, &tio);
   if (ret)
     {
       cu_error("set_termios: ERROR during tcsetattr(): %d\n", errno);
@@ -209,7 +209,7 @@ errout:
 
 static void retrieve_termios(FAR struct cu_globals_s *cu)
 {
-  tcsetattr(cu->outfd, TCSANOW, &cu->devtio);
+  tcsetattr(cu->devfd, TCSANOW, &cu->devtio);
   if (cu->stdfd >= 0)
     {
       tcsetattr(cu->stdfd, TCSANOW, &cu->stdtio);
@@ -355,10 +355,10 @@ int main(int argc, FAR char *argv[])
       return exitval;
     }
 
-  /* Open the serial device for writing */
+  /* Open the serial device for reading and writing */
 
-  cu->outfd = open(devname, O_WRONLY);
-  if (cu->outfd < 0)
+  cu->devfd = open(devname, O_RDWR);
+  if (cu->devfd < 0)
     {
       cu_error("cu_main: ERROR: Failed to open %s for writing: %d\n",
               devname, errno);
@@ -367,11 +367,11 @@ int main(int argc, FAR char *argv[])
 
   /* Remember serial device termios attributes */
 
-  ret = tcgetattr(cu->outfd, &cu->devtio);
+  ret = tcgetattr(cu->devfd, &cu->devtio);
   if (ret)
     {
       cu_error("cu_main: ERROR during tcgetattr(): %d\n", errno);
-      goto errout_with_outfd;
+      goto errout_with_devfd;
     }
 
   /* Remember std termios attributes if it is a tty. Try to select
@@ -406,19 +406,7 @@ int main(int argc, FAR char *argv[])
   if (set_termios(cu, nocrlf) != 0)
 #endif
     {
-      goto errout_with_outfd_retrieve;
-    }
-
-  /* Open the serial device for reading.  Since we are already connected,
-   * this should not fail.
-   */
-
-  cu->infd = open(devname, O_RDONLY);
-  if (cu->infd < 0)
-    {
-      cu_error("cu_main: ERROR: Failed to open %s for reading: %d\n",
-             devname, errno);
-      goto errout_with_outfd;
+      goto errout_with_devfd_retrieve;
     }
 
   /* Start the serial receiver thread */
@@ -427,7 +415,7 @@ int main(int argc, FAR char *argv[])
   if (ret != OK)
     {
       cu_error("cu_main: pthread_attr_init failed: %d\n", ret);
-      goto errout_with_fds;
+      goto errout_with_devfd_retrieve;
     }
 
   /* Set priority of listener to configured value */
@@ -439,7 +427,7 @@ int main(int argc, FAR char *argv[])
   if (ret != 0)
     {
       cu_error("cu_main: Error in thread creation: %d\n", ret);
-      goto errout_with_fds;
+      goto errout_with_devfd_retrieve;
     }
 
   /* Send messages and get responses -- forever */
@@ -458,7 +446,7 @@ int main(int argc, FAR char *argv[])
 
       if (nobreak == 1)
         {
-          write(cu->outfd, &ch, 1);
+          write(cu->devfd, &ch, 1);
           continue;
         }
 
@@ -474,7 +462,7 @@ int main(int argc, FAR char *argv[])
             {
               /* Escaping a tilde: handle like normal char */
 
-              write(cu->outfd, &ch, 1);
+              write(cu->devfd, &ch, 1);
               continue;
             }
           else
@@ -488,7 +476,7 @@ int main(int argc, FAR char *argv[])
 
       /* Normal character */
 
-      write(cu->outfd, &ch, 1);
+      write(cu->devfd, &ch, 1);
 
       /* Determine if we are now at the start of a new line or not */
 
@@ -507,12 +495,10 @@ int main(int argc, FAR char *argv[])
 
   /* Error exits */
 
-errout_with_fds:
-  close(cu->infd);
-errout_with_outfd_retrieve:
+errout_with_devfd_retrieve:
   retrieve_termios(cu);
-errout_with_outfd:
-  close(cu->outfd);
+errout_with_devfd:
+  close(cu->devfd);
 errout_with_devinit:
   return exitval;
 }