shell: avoid miscounting backslashes in read built-in

When the '-n' option was used to limit the number of characters
read, any backslashes in the input weren't correctly accounted
for.

Adds 16 bytes.

(GitHub issue #504)

1 files changed, 5 insertions, 2 deletions

diff --git a/shell/shell_common.c b/shell/shell_common.c
index 6ea08ad74..2702ef98a 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -295,7 +295,7 @@ shell_builtin_read(struct builtin_read_params *params)
                                  *   and exit BS context.
                                  * - CR LF not in BS context: replace CR with LF */
                                 buffer[--bufpos] = c;
-                                ++nchars;
+                                nchars += 1 + (backslash == 2);
                         }
                 } else if (backslash == 2) {
                         /* We saw BS CR ??, keep escaped CR, exit BS context,
@@ -315,6 +315,9 @@ shell_builtin_read(struct builtin_read_params *params)
                                 backslash = 0;
                                 if (c != '\n')
                                         goto put;
+#if ENABLE_PLATFORM_MINGW32
+                                ++nchars;
+#endif
                                 continue;
                         }
                         if (c == '\\') {
@@ -355,7 +358,7 @@ shell_builtin_read(struct builtin_read_params *params)
                 }
  put:
                 bufpos++;
-        } while (--nchars);
+        } while (IF_PLATFORM_MINGW32(backslash ||) --nchars);
 
         if (argv[0]) {
                 /* Remove trailing space $IFS chars */