hush: fix globbing+backslashes in unquoted $var expansion

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

1 files changed, 61 insertions, 73 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 2a4e80b6e..ef46372de 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2007,12 +2007,17 @@ static void o_addstr_with_NUL(o_string *o, const char *str)
 static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len)
 {
         while (len) {
+                len--;
                 o_addchr(o, *str);
-                if (*str == '\\') {
+                if (*str++ == '\\') {
+                        /* \z -> \\\z; \<eol> -> \\<eol> */
                         o_addchr(o, '\\');
+                        if (len) {
+                                len--;
+                                o_addchr(o, '\\');
+                                o_addchr(o, *str++);
+                        }
                 }
-                str++;
-                len--;
         }
 }
 
@@ -2067,12 +2072,8 @@ static void o_addQchr(o_string *o, int ch)
         o->data[o->length] = '\0';
 }
 
-static void o_addQblock(o_string *o, const char *str, int len)
+static void o_addqblock(o_string *o, const char *str, int len)
 {
-        if (!o->o_escape) {
-                o_addblock(o, str, len);
-                return;
-        }
         while (len) {
                 char ch;
                 int sz;
@@ -2099,6 +2100,15 @@ static void o_addQblock(o_string *o, const char *str, int len)
         }
 }
 
+static void o_addQblock(o_string *o, const char *str, int len)
+{
+        if (!o->o_escape) {
+                o_addblock(o, str, len);
+                return;
+        }
+        o_addqblock(o, str, len);
+}
+
 static void o_addQstr(o_string *o, const char *str)
 {
         o_addQblock(o, str, strlen(str));
@@ -2356,11 +2366,11 @@ static int glob_brace(char *pattern, o_string *o, int n)
 /* Performs globbing on last list[],
  * saving each result as a new list[].
  */
-static int o_glob(o_string *o, int n)
+static int perform_glob(o_string *o, int n)
 {
         char *pattern, *copy;
 
-        debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
+        debug_printf_glob("start perform_glob: n:%d o->data:%p\n", n, o->data);
         if (!o->data)
                 return o_save_ptr_helper(o, n);
         pattern = o->data + o_get_last_ptr(o, n);
@@ -2378,7 +2388,7 @@ static int o_glob(o_string *o, int n)
         n = glob_brace(copy, o, n);
         free(copy);
         if (DEBUG_GLOB)
-                debug_print_list("o_glob returning", o, n);
+                debug_print_list("perform_glob returning", o, n);
         return n;
 }
 
@@ -2403,13 +2413,13 @@ static int glob_needed(const char *s)
 /* Performs globbing on last list[],
  * saving each result as a new list[].
  */
-static int o_glob(o_string *o, int n)
+static int perform_glob(o_string *o, int n)
 {
         glob_t globdata;
         int gr;
         char *pattern;
 
-        debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
+        debug_printf_glob("start perform_glob: n:%d o->data:%p\n", n, o->data);
         if (!o->data)
                 return o_save_ptr_helper(o, n);
         pattern = o->data + o_get_last_ptr(o, n);
@@ -2455,7 +2465,7 @@ static int o_glob(o_string *o, int n)
         }
         globfree(&globdata);
         if (DEBUG_GLOB)
-                debug_print_list("o_glob returning", o, n);
+                debug_print_list("perform_glob returning", o, n);
         return n;
 }
 
@@ -2470,7 +2480,7 @@ static int o_save_ptr(o_string *o, int n)
                  * (if it was requested back then when it was filled)
                  * so don't do that again! */
                 if (!o->has_empty_slot)
-                        return o_glob(o, n); /* o_save_ptr_helper is inside */
+                        return perform_glob(o, n); /* o_save_ptr_helper is inside */
         }
         return o_save_ptr_helper(o, n);
 }
@@ -2927,15 +2937,6 @@ static int done_word(o_string *word, struct parse_context *ctx)
                                                 (ctx->ctx_res_w == RES_SNTX));
                                 return (ctx->ctx_res_w == RES_SNTX);
                         }
-# ifdef CMD_SINGLEWORD_NOGLOB_COND
-                        if (strcmp(word->data, "export") == 0
-#  if ENABLE_HUSH_LOCAL
-                         || strcmp(word->data, "local") == 0
-#  endif
-                        ) {
-                                command->cmd_type = CMD_SINGLEWORD_NOGLOB_COND;
-                        } else
-# endif
 # if ENABLE_HUSH_BASH_COMPAT
                         if (strcmp(word->data, "[[") == 0) {
                                 command->cmd_type = CMD_SINGLEWORD_NOGLOB;
@@ -4371,10 +4372,19 @@ static int expand_on_ifs(o_string *output, int n, const char *str)
         while (1) {
                 int word_len = strcspn(str, G.ifs);
                 if (word_len) {
-                        if (output->o_escape || !output->o_glob)
-                                o_addQblock(output, str, word_len);
-                        else /* protect backslashes against globbing up :) */
+                        if (output->o_escape)
+                                o_addqblock(output, str, word_len);
+                        else if (!output->o_glob)
+                                o_addblock(output, str, word_len);
+                        else /* if (!escape && glob) */ {
+                                /* Protect backslashes against globbing up :)
+                                 * Example: "v='\*'; echo b$v"
+                                 */
                                 o_addblock_duplicate_backslash(output, str, word_len);
+                                /*/ Why can't we do it easier? */
+                                /*o_addblock(output, str, word_len); - WRONG: "v='\*'; echo Z$v" prints "Z*" instead of "Z\*" */
+                                /*o_addqblock(output, str, word_len); - WRONG: "v='*'; echo Z$v" prints "Z*" instead of Z* files */
+                        }
                         str += word_len;
                 }
                 if (!*str)  /* EOL - do not finalize word */
@@ -4594,8 +4604,9 @@ static NOINLINE const char *expand_one_var(char **to_be_freed_pp, char *arg, cha
                                 if (exp_op == *exp_word)        /* ## or %% */
                                         exp_word++;
 //TODO: avoid xstrdup unless needed
-// (see HACK ALERT below)
+// (see HACK ALERT below for an example)
                                 val = to_be_freed = xstrdup(val);
+//TODO: fix expansion rules:
                                 exp_exp_word = expand_pseudo_dquoted(exp_word);
                                 if (exp_exp_word)
                                         exp_word = exp_exp_word;
@@ -4613,10 +4624,26 @@ static NOINLINE const char *expand_one_var(char **to_be_freed_pp, char *arg, cha
                 }
 #if ENABLE_HUSH_BASH_COMPAT
                 else if (exp_op == '/' || exp_op == '\\') {
+                        /* It's ${var/[/]pattern[/repl]} thing.
+                         * Note that in encoded form it has TWO parts:
+                         * var/pattern<SPECIAL_VAR_SYMBOL>repl<SPECIAL_VAR_SYMBOL>
+                         */
                         /* Empty variable always gives nothing: */
-                        // "v=''; echo ${v/*/w}" prints ""
+                        // "v=''; echo ${v/*/w}" prints "", not "w"
                         if (val && val[0]) {
                                 /* It's ${var/[/]pattern[/repl]} thing */
+                                /*
+                                 * Pattern is taken literally, while
+                                 * repl should be de-backslased and globbed
+                                 * by the usual expansion rules:
+                                 * >az; >bz;
+                                 * v='a bz'; echo "${v/a*z/a*z}" prints "a*z"
+                                 * v='a bz'; echo "${v/a*z/\z}"  prints "\z"
+                                 * v='a bz'; echo ${v/a*z/a*z}   prints "az"
+                                 * v='a bz'; echo ${v/a*z/\z}    prints "z"
+                                 * (note that a*z _pattern_ is never globbed!)
+                                 */
+//TODO: fix expansion rules:
                                 char *pattern, *repl, *t;
                                 pattern = expand_pseudo_dquoted(exp_word);
                                 if (!pattern)
@@ -4772,7 +4799,6 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
 
         while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
                 char first_ch;
-                int i;
                 char *to_be_freed = NULL;
                 const char *val = NULL;
 #if ENABLE_HUSH_TICK
@@ -4795,10 +4821,11 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
                 switch (first_ch & 0x7f) {
                 /* Highest bit in first_ch indicates that var is double-quoted */
                 case '*':
-                case '@':
-                        i = 1;
-                        if (!G.global_argv[i])
+                case '@': {
+                        int i;
+                        if (!G.global_argv[1])
                                 break;
+                        i = 1;
                         ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
                         if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
                                 smallint sv = output->o_escape;
@@ -4839,6 +4866,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
                                 }
                         }
                         break;
+                }
                 case SPECIAL_VAR_SYMBOL: /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
                         /* "Empty variable", used to make "" etc to not disappear */
                         arg++;
@@ -4984,41 +5012,6 @@ static char **expand_strvec_to_strvec_singleword_noglob(char **argv)
 }
 #endif
 
-#ifdef CMD_SINGLEWORD_NOGLOB_COND
-static char **expand_strvec_to_strvec_singleword_noglob_cond(char **argv)
-{
-        int n;
-        char **list;
-        char **v;
-        o_string output = NULL_O_STRING;
-
-        n = 0;
-        v = argv;
-        while (*v) {
-                int is_var = is_well_formed_var_name(*v, '=');
-                /* is_var * 0x80: singleword expansion for vars */
-                n = expand_vars_to_list(&output, n, *v, is_var * 0x80);
-
-                /* Subtle! expand_vars_to_list did not glob last word yet.
-                 * It does this only when fed with further data.
-                 * Therefore we set globbing flags AFTER it, not before:
-                 */
-
-                /* if it is not recognizably abc=...; then: */
-                output.o_escape = !is_var; /* protect against globbing for "$var" */
-                /* (unquoted $var will temporarily switch it off) */
-                output.o_glob = !is_var; /* and indeed do globbing */
-                v++;
-        }
-        debug_print_list("expand_cond", &output, n);
-
-        /* output.data (malloced in one block) gets returned in "list" */
-        list = o_finalize_list(&output, n);
-        debug_print_strings("expand_cond[1]", list);
-        return list;
-}
-#endif
-
 /* Used for expansion of right hand of assignments */
 /* NB: should NOT do globbing!
  * "export v=/bin/c*; env | grep ^v=" outputs "v=/bin/c*" */
@@ -6567,11 +6560,6 @@ static NOINLINE int run_pipe(struct pipe *pi)
                         argv_expanded = expand_strvec_to_strvec_singleword_noglob(argv + command->assignment_cnt);
                 }
 #endif
-#ifdef CMD_SINGLEWORD_NOGLOB_COND
-                else if (command->cmd_type == CMD_SINGLEWORD_NOGLOB_COND) {
-                        argv_expanded = expand_strvec_to_strvec_singleword_noglob_cond(argv + command->assignment_cnt);
-                }
-#endif
                 else {
                         argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
                 }