hush: fix handling of \^C and "^C"

function                                             old     new   delta
parse_stream                                        2238    2252     +14
encode_string                                        243     256     +13
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 27/0)               Total: 27 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
(cherry picked from commit 1b7a9b68d0e9aa19147d7fda16eb9a6b54156985)

9 files changed, 23 insertions, 0 deletions

diff --git a/shell/ash_test/ash-misc/control_char3.right b/shell/ash_test/ash-misc/control_char3.right
new file mode 100644
index 000000000..283e02cbb
--- /dev/null
+++ b/shell/ash_test/ash-misc/control_char3.right
@@ -0,0 +1 @@
+SHELL: line 1: : not found
diff --git a/shell/ash_test/ash-misc/control_char3.tests b/shell/ash_test/ash-misc/control_char3.tests
new file mode 100755
index 000000000..4359db3f3
--- /dev/null
+++ b/shell/ash_test/ash-misc/control_char3.tests
@@ -0,0 +1,2 @@
+# (set argv0 to "SHELL" to avoid "/path/to/shell: blah" in error messages)
+$THIS_SH -c '\' SHELL
diff --git a/shell/ash_test/ash-misc/control_char4.right b/shell/ash_test/ash-misc/control_char4.right
new file mode 100644
index 000000000..2bf18e684
--- /dev/null
+++ b/shell/ash_test/ash-misc/control_char4.right
@@ -0,0 +1 @@
+SHELL: line 1: -: not found
diff --git a/shell/ash_test/ash-misc/control_char4.tests b/shell/ash_test/ash-misc/control_char4.tests
new file mode 100755
index 000000000..48010f154
--- /dev/null
+++ b/shell/ash_test/ash-misc/control_char4.tests
@@ -0,0 +1,2 @@
+# (set argv0 to "SHELL" to avoid "/path/to/shell: blah" in error messages)
+$THIS_SH -c '"-"' SHELL
diff --git a/shell/hush.c b/shell/hush.c
index 9fead37da..249728b9d 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -5235,6 +5235,11 @@ static int encode_string(o_string *as_string,
         }
 #endif
         o_addQchr(dest, ch);
+        if (ch == SPECIAL_VAR_SYMBOL) {
+                /* Convert "^C" to corresponding special variable reference */
+                o_addchr(dest, SPECIAL_VAR_QUOTED_SVS);
+                o_addchr(dest, SPECIAL_VAR_SYMBOL);
+        }
         goto again;
 #undef as_string
 }
@@ -5346,6 +5351,11 @@ static struct pipe *parse_stream(char **pstring,
                         if (ch == '\n')
                                 continue; /* drop \<newline>, get next char */
                         nommu_addchr(&ctx.as_string, '\\');
+                        if (ch == SPECIAL_VAR_SYMBOL) {
+                                nommu_addchr(&ctx.as_string, ch);
+                                /* Convert \^C to corresponding special variable reference */
+                                goto case_SPECIAL_VAR_SYMBOL;
+                        }
                         o_addchr(&ctx.word, '\\');
                         if (ch == EOF) {
                                 /* Testcase: eval 'echo Ok\' */
@@ -5670,6 +5680,7 @@ static struct pipe *parse_stream(char **pstring,
                 /* Note: nommu_addchr(&ctx.as_string, ch) is already done */
 
                 switch (ch) {
+                case_SPECIAL_VAR_SYMBOL:
                 case SPECIAL_VAR_SYMBOL:
                         /* Convert raw ^C to corresponding special variable reference */
                         o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL);
diff --git a/shell/hush_test/hush-misc/control_char3.right b/shell/hush_test/hush-misc/control_char3.right
new file mode 100644
index 000000000..94b4f8699
--- /dev/null
+++ b/shell/hush_test/hush-misc/control_char3.right
@@ -0,0 +1 @@
+hush: can't execute '': No such file or directory
diff --git a/shell/hush_test/hush-misc/control_char3.tests b/shell/hush_test/hush-misc/control_char3.tests
new file mode 100755
index 000000000..4359db3f3
--- /dev/null
+++ b/shell/hush_test/hush-misc/control_char3.tests
@@ -0,0 +1,2 @@
+# (set argv0 to "SHELL" to avoid "/path/to/shell: blah" in error messages)
+$THIS_SH -c '\' SHELL
diff --git a/shell/hush_test/hush-misc/control_char4.right b/shell/hush_test/hush-misc/control_char4.right
new file mode 100644
index 000000000..698e21427
--- /dev/null
+++ b/shell/hush_test/hush-misc/control_char4.right
@@ -0,0 +1 @@
+hush: can't execute '-': No such file or directory
diff --git a/shell/hush_test/hush-misc/control_char4.tests b/shell/hush_test/hush-misc/control_char4.tests
new file mode 100755
index 000000000..48010f154
--- /dev/null
+++ b/shell/hush_test/hush-misc/control_char4.tests
@@ -0,0 +1,2 @@
+# (set argv0 to "SHELL" to avoid "/path/to/shell: blah" in error messages)
+$THIS_SH -c '"-"' SHELL