1 files changed, 181 insertions, 2 deletions

diff --git a/cpukit/libmisc/shell/shell.c b/cpukit/libmisc/shell/shell.c
index 64f90be121..9cefc80255 100644
--- a/cpukit/libmisc/shell/shell.c
+++ b/cpukit/libmisc/shell/shell.c
@@ -1,6 +1,6 @@
 /**
  * @file
- * 
+ *
  * @brief Instantatiate a new terminal shell.
  */
 
@@ -805,6 +805,183 @@ void rtems_shell_print_env(
 }
 #endif
 
+/*
+ * Wait for the string to return or timeout.
+ */
+static bool rtems_shell_term_wait_for(const int fd, const char* str, const int timeout)
+{
+  int msec = timeout;
+  int i = 0;
+  while (msec-- > 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;
+    } else {
+      usleep(1000);
+    }
+  }
+  if (msec == 0) {
+    return false;
+  }
+  return true;
+}
+
+/*
+ * Buffer a string up to the end string
+ */
+static int rtems_shell_term_buffer_until(const int fd,
+                                         char* buf,
+                                         const int size,
+                                         const char* end,
+                                         const int timeout)
+{
+  int msec = timeout;
+  int i = 0;
+  int e = 0;
+  memset(&buf[0], 0, size);
+  while (msec-- > 0 && i < size && end[e] != '\0') {
+    char ch[2];
+    if (read(fd, &ch[0], 1) == 1) {
+      fflush(stdout);
+      buf[i++] = ch[0];
+      if (ch[0] == end[e]) {
+        e++;
+      } else {
+        e = 0;
+      }
+      msec = timeout;
+    } else {
+      usleep(1000);
+    }
+  }
+  if (msec == 0 || end[e] != '\0') {
+    return -1;
+  }
+  i -= e;
+  if (i < size) {
+    buf[i] = '\0';
+  }
+  return i;
+}
+
+/*
+ * Determine if the terminal has the row and column values
+ * swapped
+ *
+ * https://github.com/tmux/tmux/issues/3457
+ *
+ * Tmux has a bug where the lines and cols are swapped. There is a lag
+ * in the time it takes to get the fix into code so see if tmux is
+ * running and which version and work around the bug.
+ *
+ * The terminal device needs to have VMIN=0, and VTIME=0
+ */
+static bool rtems_shell_term_row_column_swapped(const int fd, const int timeout) {
+  char buf[64];
+  memset(&buf[0], 0, sizeof(buf));
+  /*
+   * CSI > Ps q
+   *    Ps = 0   =>   DCS > | text ST
+   */
+  fputs("\033[>0q", stdout);
+  fflush(stdout);
+  if (rtems_shell_term_wait_for(fd, "\033P>|", timeout)) {
+    int len = rtems_shell_term_buffer_until(fd, buf, sizeof(buf), "\033\\", timeout);
+    if (len > 0) {
+      if (memcmp(buf, "tmux ", 5) == 0) {
+        static const char* bad_versions[] = {
+          "3.2", "3.2a", "3.3", "3.3a"
+        };
+        size_t i;
+        for (i = 0; i < RTEMS_ARRAY_SIZE(bad_versions); ++i) {
+          if (strcmp(bad_versions[i], buf + 5) == 0) {
+            return true;
+          }
+        }
+      }
+    }
+  }
+  return false;
+}
+
+/*
+ * Direct method to get the size of an XTERM window.
+ *
+ * If you do not use an XTERM the env variables are not define.
+ */
+static void rtems_shell_winsize( void )
+{
+  const int fd = fileno(stdin);
+  struct winsize ws;
+  const int timeout = 150;
+  char buf[64];
+  bool ok = false;
+  int lines = 0;
+  int cols = 0;
+  int r;
+  r = ioctl(fd, TIOCGWINSZ, &ws);
+  if (r == 0) {
+    ok = true;
+    lines = ws.ws_row;
+    cols = ws.ws_col;
+  } else if (isatty(fd)) {
+    struct termios cterm;
+    if (tcgetattr(fd, &cterm) >= 0) {
+      struct termios term = cterm;
+      term.c_cc[VMIN] = 0;
+      term.c_cc[VTIME] = 0;
+      if (tcsetattr (fd, TCSADRAIN, &term) >= 0) {
+        memset(&buf[0], 0, sizeof(buf));
+        /*
+         * https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-Miscellaneous
+         *
+         * CSI 1 8 t
+         */
+        fputs("\033[18t", stdout);
+        fflush(stdout);
+        if (rtems_shell_term_wait_for(fd, "\033[8;", timeout)) {
+          int len = rtems_shell_term_buffer_until(fd, buf, sizeof(buf), ";", timeout);
+          if (len > 0) {
+            int i;
+            lines = 0;
+            i = 0;
+            while (i < len) {
+              lines *= 10;
+              lines += buf[i++] - '0';
+            }
+            len = rtems_shell_term_buffer_until(fd, buf, sizeof(buf), "t", timeout);
+            if (len > 0) {
+              cols = 0;
+              i = 0;
+              while (i < len) {
+                cols *= 10;
+                cols += buf[i++] - '0';
+              }
+              ok = true;
+            }
+          }
+        }
+      }
+      if (rtems_shell_term_row_column_swapped(fd, timeout)) {
+        int tmp = lines;
+        lines = cols;
+        cols = tmp;
+      }
+      tcsetattr (fd, TCSADRAIN, &cterm);
+    }
+  }
+  if (ok) {
+    snprintf(buf, sizeof(buf) - 1, "%d", lines);
+    setenv("LINES", buf, 1);
+    snprintf(buf, sizeof(buf) - 1, "%d", cols);
+    setenv("COLUMNS", buf, 1);
+  }
+}
+
 static rtems_task rtems_shell_task(rtems_task_argument task_argument)
 {
   rtems_shell_env_t *shell_env = (rtems_shell_env_t*) task_argument;
@@ -984,7 +1161,9 @@ static bool shell_main_loop(
           memcpy (cmd_argv, cmds[cmd], RTEMS_SHELL_CMD_SIZE);
           if (!rtems_shell_make_args(cmd_argv, &argc, argv,
                                      RTEMS_SHELL_MAXIMUM_ARGUMENTS)) {
-            int exit_code = rtems_shell_execute_cmd(argv[0], argc, argv);
+            int exit_code;
+            rtems_shell_winsize();
+            exit_code = rtems_shell_execute_cmd(argv[0], argc, argv);
             if (shell_env->exit_code != NULL)
               *shell_env->exit_code = exit_code;
             if (exit_code != 0 && shell_env->exit_on_error)