(nuttx-apps) branch master updated: examples: gps: bound NMEA line reads

[xiaoxiang]

This is an automated email from the ASF dual-hosted git repository.

xiaoxiang781216 pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/nuttx-apps.git


The following commit(s) were added to refs/heads/master by this push:
     new e94e89113 examples: gps: bound NMEA line reads
e94e89113 is described below

commit e94e89113a39649bdd7d617c99c2302f5df6ecac
Author: Old-Ding <35417409+old-d...@users.noreply.github.com>
AuthorDate: Mon Jul 6 05:45:03 2026 +0800

    examples: gps: bound NMEA line reads
    
    The GPS example appends serial input to a fixed-size NMEA line buffer until 
CR or LF without checking the buffer limit. A malformed or overlong input line 
can write past the end of line[], and the code also uses ch even when read() 
does not return a byte.
    
    Read bytes only after a successful read(), stop storing at 
MINMEA_MAX_LENGTH - 1, drain overlong lines until the line ending, and skip 
parsing truncated sentences.
    
    Generated-by: OpenAI Codex
    Signed-off-by: Old-Ding <35417409+old-d...@users.noreply.github.com>
---
 examples/gps/gps_main.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/examples/gps/gps_main.c b/examples/gps/gps_main.c
index 68f6da66e..a308f5213 100644
--- a/examples/gps/gps_main.c
+++ b/examples/gps/gps_main.c
@@ -26,6 +26,7 @@
 
 #include <nuttx/config.h>
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <fcntl.h>
 #include <wchar.h>
@@ -52,9 +53,11 @@ int main(int argc, FAR char *argv[])
 {
   int fd;
   int cnt;
+  ssize_t nread;
   char ch;
   char line[MINMEA_MAX_LENGTH];
   char *port = "/dev/ttyS1";
+  bool truncated;
 
   /* Get the GPS serial port argument. If none specified, default to ttyS1 */
 
@@ -79,18 +82,38 @@ int main(int argc, FAR char *argv[])
       /* Read until we complete a line */
 
       cnt = 0;
-      do
+      truncated = false;
+
+      for (; ; )
         {
-          read(fd, &ch, 1);
-          if (ch != '\r' && ch != '\n')
+          nread = read(fd, &ch, 1);
+          if (nread <= 0)
+            {
+              continue;
+            }
+
+          if (ch == '\r' || ch == '\n')
+            {
+              break;
+            }
+
+          if (cnt < MINMEA_MAX_LENGTH - 1)
             {
               line[cnt++] = ch;
             }
+          else
+            {
+              truncated = true;
+            }
         }
-      while (ch != '\r' && ch != '\n');
 
       line[cnt] = '\0';
 
+      if (truncated)
+        {
+          continue;
+        }
+
       switch (minmea_sentence_id(line, false))
         {
           case MINMEA_SENTENCE_RMC: