hush: implement $LINENO bashism

function                                             old     new   delta
run_pipe                                            1697    1774     +77
unset_local_var_len                                  258     301     +43
hush_main                                           1009    1051     +42
set_local_var                                        516     554     +38
parse_and_run_file                                    42      75     +33
i_getch                                               96     116     +20
.rodata                                            18858   18876     +18
done_command                                         106     122     +16
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 8/0 up/down: 287/0)             Total: 287 bytes

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

3 files changed, 68 insertions, 2 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 79d7a53dd..8ba48de95 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -361,6 +361,7 @@
 #define BASH_SUBSTR        ENABLE_HUSH_BASH_COMPAT
 #define BASH_SOURCE        ENABLE_HUSH_BASH_COMPAT
 #define BASH_HOSTNAME_VAR  ENABLE_HUSH_BASH_COMPAT
+#define BASH_LINENO_VAR    ENABLE_HUSH_BASH_COMPAT
 #define BASH_TEST2         (ENABLE_HUSH_BASH_COMPAT && ENABLE_HUSH_TEST)
 #define BASH_READ_D        ENABLE_HUSH_BASH_COMPAT
 
@@ -612,6 +613,9 @@ typedef enum redir_type {
 struct command {
         pid_t pid;                  /* 0 if exited */
         int assignment_cnt;         /* how many argv[i] are assignments? */
+#if BASH_LINENO_VAR
+        unsigned lineno;
+#endif
         smallint cmd_type;          /* CMD_xxx */
 #define CMD_NORMAL   0
 #define CMD_SUBSHELL 1
@@ -931,6 +935,13 @@ struct globals {
         unsigned handled_SIGCHLD;
         smallint we_have_children;
 #endif
+#if BASH_LINENO_VAR
+        unsigned lineno;
+        char *lineno_var;
+# define G_lineno_var G.lineno_var
+#else
+# define G_lineno_var ((char*)NULL)
+#endif
         struct FILE_list *FILE_list;
         /* Which signals have non-DFL handler (even with no traps set)?
          * Set at the start to:
@@ -2135,6 +2146,13 @@ static int set_local_var(char *str, unsigned flags)
         }
 
         name_len = eq_sign - str + 1; /* including '=' */
+#if BASH_LINENO_VAR
+        if (G.lineno_var) {
+                if (name_len == 7 && strncmp("LINENO", str, 6) == 0)
+                        G.lineno_var = NULL;
+        }
+#endif
+
         var_pp = &G.top_var;
         while ((cur = *var_pp) != NULL) {
                 if (strncmp(cur->varstr, str, name_len) != 0) {
@@ -2256,10 +2274,16 @@ static int unset_local_var_len(const char *name, int name_len)
 
         if (!name)
                 return EXIT_SUCCESS;
+
 #if ENABLE_HUSH_GETOPTS
         if (name_len == 6 && strncmp(name, "OPTIND", 6) == 0)
                 G.getopt_count = 0;
 #endif
+#if BASH_LINENO_VAR
+        if (name_len == 6 && G.lineno_var && strncmp(name, "LINENO", 6) == 0)
+                G.lineno_var = NULL;
+#endif
+
         var_pp = &G.top_var;
         while ((cur = *var_pp) != NULL) {
                 if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
@@ -2578,6 +2602,10 @@ static int i_getch(struct in_str *i)
  out:
         debug_printf("file_get: got '%c' %d\n", ch, ch);
         i->last_char = ch;
+#if BASH_LINENO_VAR
+        if (ch == '\n')
+                G.lineno++;
+#endif
         return ch;
 }
 
@@ -3460,6 +3488,9 @@ static int done_command(struct parse_context *ctx)
         ctx->command = command = &pi->cmds[pi->num_cmds];
  clear_and_ret:
         memset(command, 0, sizeof(*command));
+#if BASH_LINENO_VAR
+        command->lineno = G.lineno;
+#endif
         return pi->num_cmds; /* used only for 0/nonzero check */
 }
 
@@ -6520,8 +6551,13 @@ static void parse_and_run_string(const char *s)
 static void parse_and_run_file(FILE *f)
 {
         struct in_str input;
+        unsigned sv;
+
         setup_file_in_str(&input, f);
+        sv = G.lineno;
+        G.lineno = 1;
         parse_and_run_stream(&input, ';');
+        G.lineno = sv;
 }
 
 #if ENABLE_HUSH_TICK
@@ -8068,6 +8104,9 @@ static NOINLINE int run_pipe(struct pipe *pi)
                 char **new_env = NULL;
                 struct variable *old_vars = NULL;
 
+                if (G_lineno_var)
+                        strcpy(G_lineno_var + sizeof("LINENO=")-1, utoa(command->lineno));
+
                 if (argv[command->assignment_cnt] == NULL) {
                         /* Assignments, but no command */
                         /* Ensure redirects take effect (that is, create files).
@@ -8272,6 +8311,9 @@ static NOINLINE int run_pipe(struct pipe *pi)
                 if (cmd_no < pi->num_cmds)
                         xpiped_pair(pipefds);
 
+                if (G_lineno_var)
+                        strcpy(G_lineno_var + sizeof("LINENO=")-1, utoa(command->lineno));
+
                 command->pid = BB_MMU ? fork() : vfork();
                 if (!command->pid) { /* child */
 #if ENABLE_HUSH_JOB
@@ -8907,17 +8949,19 @@ int hush_main(int argc, char **argv)
 #if !BB_MMU
         G.argv0_for_re_execing = argv[0];
 #endif
+
         /* Deal with HUSH_VERSION */
+        debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
+        unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
         shell_ver = xzalloc(sizeof(*shell_ver));
         shell_ver->flg_export = 1;
         shell_ver->flg_read_only = 1;
         /* Code which handles ${var<op>...} needs writable values for all variables,
          * therefore we xstrdup: */
         shell_ver->varstr = xstrdup(hush_version_str);
+
         /* Create shell local variables from the values
          * currently living in the environment */
-        debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
-        unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
         G.top_var = shell_ver;
         cur_var = G.top_var;
         e = environ;
@@ -8983,6 +9027,14 @@ int hush_main(int argc, char **argv)
          */
 #endif
 
+#if BASH_LINENO_VAR
+        if (BASH_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
diff --git a/shell/hush_test/hush-vars/var_LINENO1.right b/shell/hush_test/hush-vars/var_LINENO1.right
new file mode 100644
index 000000000..31e1a4478
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_LINENO1.right
@@ -0,0 +1,8 @@
+2:2
+3:3
+4:4
+5:5
+2:2
+3:3
+4:4
+5:5
diff --git a/shell/hush_test/hush-vars/var_LINENO1.tests b/shell/hush_test/hush-vars/var_LINENO1.tests
new file mode 100755
index 000000000..851b52cf5
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_LINENO1.tests
@@ -0,0 +1,6 @@
+env | grep LINENO
+echo 2:$LINENO
+echo 3:$LINENO >&2 \
+| { sleep 0.1; echo 4:$LINENO; }
+echo 5:$LINENO
+test "$1" || . ./var_LINENO1.tests norepeat