hush: handle LINENO the same way as RANDOM: variable is "ephemeral"

"env - hush" invocation (that is, with empty environment)
should not show LINENO in "set" output.

function                                             old     new   delta
get_local_var_value                                  263     294     +31
hush_main                                           1105    1070     -35
handle_changed_special_names                          79      38     -41
run_pipe                                            1834    1765     -69
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/3 up/down: 31/-145)          Total: -114 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 18 insertions, 32 deletions

diff --git a/shell/hush.c b/shell/hush.c
index e2927afc4..629b7ff92 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -967,8 +967,8 @@ struct globals {
         smallint we_have_children;
 #endif
 #if ENABLE_HUSH_LINENO_VAR
-        unsigned lineno;
-        char *lineno_var;
+        unsigned parse_lineno;
+        unsigned execute_lineno;
 #endif
         HFILE *HFILE_list;
         /* Which signals have non-DFL handler (even with no traps set)?
@@ -2221,6 +2221,10 @@ static const char* FAST_FUNC get_local_var_value(const char *name)
         if (strcmp(name, "RANDOM") == 0)
                 return utoa(next_random(&G.random_gen));
 #endif
+#if ENABLE_HUSH_LINENO_VAR
+        if (strcmp(name, "LINENO") == 0)
+                return utoa(G.execute_lineno);
+#endif
 #if BASH_EPOCH_VARS
         {
                 const char *fmt = NULL;
@@ -2240,22 +2244,14 @@ static const char* FAST_FUNC get_local_var_value(const char *name)
         return NULL;
 }
 
-#if ENABLE_HUSH_LINENO_VAR || ENABLE_HUSH_GETOPTS
+#if ENABLE_HUSH_GETOPTS
 static void handle_changed_special_names(const char *name, unsigned name_len)
 {
         if (name_len == 6) {
-# if ENABLE_HUSH_LINENO_VAR
-                if (strncmp(name, "LINENO", 6) == 0) {
-                        G.lineno_var = NULL;
-                        return;
-                }
-# endif
-# if ENABLE_HUSH_GETOPTS
                 if (strncmp(name, "OPTIND", 6) == 0) {
                         G.getopt_count = 0;
                         return;
                 }
-# endif
         }
 }
 #else
@@ -2727,8 +2723,8 @@ static int i_getch(struct in_str *i)
         i->last_char = ch;
 #if ENABLE_HUSH_LINENO_VAR
         if (ch == '\n') {
-                G.lineno++;
-                debug_printf_parse("G.lineno++ = %u\n", G.lineno);
+                G.parse_lineno++;
+                debug_printf_parse("G.parse_lineno++ = %u\n", G.parse_lineno);
         }
 #endif
         return ch;
@@ -3730,8 +3726,8 @@ static int done_command(struct parse_context *ctx)
  clear_and_ret:
         memset(command, 0, sizeof(*command));
 #if ENABLE_HUSH_LINENO_VAR
-        command->lineno = G.lineno;
-        debug_printf_parse("command->lineno = G.lineno (%u)\n", G.lineno);
+        command->lineno = G.parse_lineno;
+        debug_printf_parse("command->lineno = G.parse_lineno (%u)\n", G.parse_lineno);
 #endif
         return pi->num_cmds; /* used only for 0/nonzero check */
 }
@@ -7261,22 +7257,22 @@ static void parse_and_run_stream(struct in_str *inp, int end_trigger)
 static void parse_and_run_string(const char *s)
 {
         struct in_str input;
-        //IF_HUSH_LINENO_VAR(unsigned sv = G.lineno;)
+        //IF_HUSH_LINENO_VAR(unsigned sv = G.parse_lineno;)
 
         setup_string_in_str(&input, s);
         parse_and_run_stream(&input, '\0');
-        //IF_HUSH_LINENO_VAR(G.lineno = sv;)
+        //IF_HUSH_LINENO_VAR(G.parse_lineno = sv;)
 }
 
 static void parse_and_run_file(HFILE *fp)
 {
         struct in_str input;
-        IF_HUSH_LINENO_VAR(unsigned sv = G.lineno;)
+        IF_HUSH_LINENO_VAR(unsigned sv = G.parse_lineno;)
 
-        IF_HUSH_LINENO_VAR(G.lineno = 1;)
+        IF_HUSH_LINENO_VAR(G.parse_lineno = 1;)
         setup_file_in_str(&input, fp);
         parse_and_run_stream(&input, ';');
-        IF_HUSH_LINENO_VAR(G.lineno = sv;)
+        IF_HUSH_LINENO_VAR(G.parse_lineno = sv;)
 }
 
 #if ENABLE_HUSH_TICK
@@ -8975,8 +8971,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
                 struct variable *old_vars;
 
 #if ENABLE_HUSH_LINENO_VAR
-                if (G.lineno_var)
-                        strcpy(G.lineno_var + sizeof("LINENO=")-1, utoa(command->lineno));
+                G.execute_lineno = command->lineno;
 #endif
 
                 if (argv[command->assignment_cnt] == NULL) {
@@ -9209,8 +9204,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
                         xpiped_pair(pipefds);
 
 #if ENABLE_HUSH_LINENO_VAR
-                if (G.lineno_var)
-                        strcpy(G.lineno_var + sizeof("LINENO=")-1, utoa(command->lineno));
+                G.execute_lineno = command->lineno;
 #endif
 
                 command->pid = BB_MMU ? fork() : vfork();
@@ -9946,14 +9940,6 @@ int hush_main(int argc, char **argv)
          * PS4='+ '
          */
 
-#if ENABLE_HUSH_LINENO_VAR
-        if (ENABLE_HUSH_LINENO_VAR) {
-                char *p = xasprintf("LINENO=%*s", (int)(sizeof(int)*3), "");
-                set_local_var(p, /*flags*/ 0);
-                G.lineno_var = p; /* can't assign before set_local_var("LINENO=...") */
-        }
-#endif
-
 #if ENABLE_FEATURE_EDITING
         G.line_input_state = new_line_input_t(FOR_SHELL);
 #endif