From 8eb4932b1395ad90283aca141b6af5fd3920db4a Mon Sep 17 00:00:00 2001
From: Kinsey Moore <kinsey.moore@oarcorp.com>
Date: Thu, 11 Jul 2024 21:34:09 -0500
Subject: [PATCH] cpukit/shell: Account for tick rate in timeouts

On systems that don't provide a proper terminal or have broken window
size detection, the RTEMS shell can take a long time execute commands if
the kernel tick interval is longer than 1ms. This updates the shell
window size retrieval timeout code to account for the kernel tick
interval bringing the experienced timeout from 12.5ms to 1.25ms when
using the default kernel tick interval (10ms).
---
 cpukit/libmisc/shell/shell.c | 37 ++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/cpukit/libmisc/shell/shell.c b/cpukit/libmisc/shell/shell.c
index 9cefc80255..9c47a3f566 100644
--- a/cpukit/libmisc/shell/shell.c
+++ b/cpukit/libmisc/shell/shell.c
@@ -805,26 +805,38 @@ void rtems_shell_print_env(
 }
 #endif
 
+static int get_ticks_from_ms(const int timeout_ms)
+{
+  int ticks = timeout_ms * 1000;
+
+  ticks /= rtems_configuration_get_microseconds_per_tick();
+
+  return MAX(1, ticks);
+}
+
 /*
  * Wait for the string to return or timeout.
  */
-static bool rtems_shell_term_wait_for(const int fd, const char* str, const int timeout)
+static bool rtems_shell_term_wait_for(const int fd,
+                                      const char* str,
+                                      const int timeout_ms)
 {
-  int msec = timeout;
+  const int timeout_ticks = get_ticks_from_ms(timeout_ms);
+  int tick_count = timeout_ticks;
   int i = 0;
-  while (msec-- > 0 && str[i] != '\0') {
+  while (tick_count-- > 0 && str[i] != '\0') {
     char ch[2];
     if (read(fd, &ch[0], 1) == 1) {
       fflush(stdout);
       if (ch[0] != str[i++]) {
         return false;
       }
-      msec = timeout;
+      tick_count = timeout_ticks;
     } else {
-      usleep(1000);
+      rtems_task_wake_after(1);
     }
   }
-  if (msec == 0) {
+  if (tick_count == 0) {
     return false;
   }
   return true;
@@ -837,13 +849,14 @@ static int rtems_shell_term_buffer_until(const int fd,
                                          char* buf,
                                          const int size,
                                          const char* end,
-                                         const int timeout)
+                                         const int timeout_ms)
 {
-  int msec = timeout;
+  const int timeout_ticks = get_ticks_from_ms(timeout_ms);
+  int tick_count = timeout_ticks;
   int i = 0;
   int e = 0;
   memset(&buf[0], 0, size);
-  while (msec-- > 0 && i < size && end[e] != '\0') {
+  while (tick_count-- > 0 && i < size && end[e] != '\0') {
     char ch[2];
     if (read(fd, &ch[0], 1) == 1) {
       fflush(stdout);
@@ -853,12 +866,12 @@ static int rtems_shell_term_buffer_until(const int fd,
       } else {
         e = 0;
       }
-      msec = timeout;
+      tick_count = timeout_ticks;
     } else {
-      usleep(1000);
+      rtems_task_wake_after(1);
     }
   }
-  if (msec == 0 || end[e] != '\0') {
+  if (tick_count == 0 || end[e] != '\0') {
     return -1;
   }
   i -= e;