hush: fix handling of backslashes in variable assignment

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

5 files changed, 74 insertions, 41 deletions

diff --git a/shell/ash_test/ash-vars/var_bash5.tests b/shell/ash_test/ash-vars/var_bash5.tests
index 3f49321e1..7f482a554 100755
--- a/shell/ash_test/ash-vars/var_bash5.tests
+++ b/shell/ash_test/ash-vars/var_bash5.tests
@@ -1,5 +1,5 @@
-# This testcase checks whether slashes in ${v/a/b} are parsed before or after expansions
-# in a part
+# This testcase checks whether slashes in ${v/a/b} are parsed before
+# or after expansions
 
 v='a/b/c'
 s='b/c'
diff --git a/shell/hush.c b/shell/hush.c
index e8dfb2499..d3dab5863 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -390,6 +390,7 @@ typedef struct o_string {
         smallint o_glob;
         /* At least some part of the string was inside '' or "",
          * possibly empty one: word"", wo''rd etc. */
+//TODO: rename to no_empty_expansion?
         smallint o_quoted;
         smallint has_empty_slot;
         smallint o_assignment; /* 0:maybe, 1:yes, 2:no */
@@ -2018,11 +2019,10 @@ static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len
 {
         while (len) {
                 o_addchr(o, *str);
-                if (*str++ == '\\'
-                 && (*str != '*' && *str != '?' && *str != '[')
-                ) {
+                if (*str == '\\') {
                         o_addchr(o, '\\');
                 }
+                str++;
                 len--;
         }
 }
@@ -2128,8 +2128,8 @@ static void debug_print_list(const char *prefix, o_string *o, int n)
         int i = 0;
 
         indent();
-        fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n",
-                        prefix, list, n, string_start, o->length, o->maxlen);
+        fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d glob:%d quoted:%d escape:%d\n",
+                        prefix, list, n, string_start, o->length, o->maxlen, o->o_glob, o->o_quoted, o->o_escape);
         while (i < n) {
                 indent();
                 fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i],
@@ -2563,9 +2563,9 @@ static char *expand_pseudo_dquoted(const char *str)
         struct in_str input;
         o_string dest = NULL_O_STRING;
 
-        if (strchr(str, '$') == NULL
+        if (!strchr(str, '$')
 #if ENABLE_HUSH_TICK
-         && strchr(str, '`') == NULL
+         && !strchr(str, '`')
 #endif
         ) {
                 return NULL;
@@ -2740,6 +2740,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
                 }
 #endif
                 default: { /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
+//TODO: move to a subroutine?
                         char *var;
                         char first_char;
                         char exp_op;
@@ -3000,18 +3001,22 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
         return n;
 }
 
-static char **expand_variables(char **argv, int or_mask)
+enum {
+        EXPVAR_FLAG_GLOB = 0x200,
+        EXPVAR_FLAG_ESCAPE_VARS = 0x100,
+        EXPVAR_FLAG_SINGLEWORD = 0x80, /* must be 0x80 */
+};
+static char **expand_variables(char **argv, unsigned or_mask)
 {
         int n;
         char **list;
         char **v;
         o_string output = NULL_O_STRING;
 
-        if (or_mask & 0x100) {
-                output.o_escape = 1; /* protect against globbing for "$var" */
-                /* (unquoted $var will temporarily switch it off) */
-                output.o_glob = 1;
-        }
+        /* protect against globbing for "$var"? */
+        /* (unquoted $var will temporarily switch it off) */
+        output.o_escape = 1 & (or_mask / EXPVAR_FLAG_ESCAPE_VARS);
+        output.o_glob = 1 & (or_mask / EXPVAR_FLAG_GLOB);
 
         n = 0;
         v = argv;
@@ -3029,13 +3034,13 @@ static char **expand_variables(char **argv, int or_mask)
 
 static char **expand_strvec_to_strvec(char **argv)
 {
-        return expand_variables(argv, 0x100);
+        return expand_variables(argv, EXPVAR_FLAG_GLOB | EXPVAR_FLAG_ESCAPE_VARS);
 }
 
 #if ENABLE_HUSH_BASH_COMPAT
 static char **expand_strvec_to_strvec_singleword_noglob(char **argv)
 {
-        return expand_variables(argv, 0x80);
+        return expand_variables(argv, EXPVAR_FLAG_SINGLEWORD);
 }
 #endif
 
@@ -3075,15 +3080,15 @@ static char **expand_strvec_to_strvec_singleword_noglob_cond(char **argv)
 #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*" */
+/* NB: should NOT do globbing!
+ * "export v=/bin/c*; env | grep ^v=" outputs "v=/bin/c*" */
 static char *expand_string_to_string(const char *str)
 {
         char *argv[2], **list;
 
         argv[0] = (char*)str;
         argv[1] = NULL;
-        list = expand_variables(argv, 0x80); /* 0x80: singleword expansion */
+        list = expand_variables(argv, EXPVAR_FLAG_ESCAPE_VARS | EXPVAR_FLAG_SINGLEWORD);
         if (HUSH_DEBUG)
                 if (!list[0] || list[1])
                         bb_error_msg_and_die("BUG in varexp2");
@@ -3099,7 +3104,7 @@ static char* expand_strvec_to_string(char **argv)
 {
         char **list;
 
-        list = expand_variables(argv, 0x80);
+        list = expand_variables(argv, EXPVAR_FLAG_SINGLEWORD);
         /* Convert all NULs to spaces */
         if (list[0]) {
                 int n = 1;
diff --git a/shell/hush_test/hush-vars/var_unbackslash.right b/shell/hush_test/hush-vars/var_unbackslash.right
new file mode 100644
index 000000000..20c2ddf55
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_unbackslash.right
@@ -0,0 +1,11 @@
+b1=-qwerty-t-\-"---z-*-?-
+b1=-qwerty-t-\-"---z-*-?-
+b2=-qwerty-\t-\-"-\--\z-\*-\?-
+b2=-qwerty-\t-\-"-\--\z-\*-\?-
+b3=-$a-\t-\\-\"-\--\z-\*-\?-
+b3=-$a-\t-\\-\"-\--\z-\*-\?-
+c=-$a-\t-\\-\"-\--\z-\*-\?-
+c=-$a-\t-\\-\"-\--\z-\*-\?-
+c=-$a-\t-\\-\"-\--\z-\*-\?-
+c=-$a-\t-\\-\"-\--\z-\*-\?-
+Done: 0
diff --git a/shell/hush_test/hush-vars/var_unbackslash.tests b/shell/hush_test/hush-vars/var_unbackslash.tests
new file mode 100755
index 000000000..3c35d7df5
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_unbackslash.tests
@@ -0,0 +1,23 @@
+# Test for correct handling of backslashes
+a=qwerty
+
+b=-$a-\t-\\-\"-\--\z-\*-\?-
+echo b1=$b
+echo "b1=$b"
+b="-$a-\t-\\-\"-\--\z-\*-\?-"
+echo b2=$b
+echo "b2=$b"
+b='-$a-\t-\\-\"-\--\z-\*-\?-'
+echo b3=$b
+echo "b3=$b"
+
+c=$b
+echo "c=$c"
+c=${b}
+echo "c=$c"
+c="$b"
+echo "c=$c"
+c="${b}"
+echo "c=$c"
+
+echo "Done: $?"
diff --git a/shell/match.c b/shell/match.c
index 8b1ddacd5..01b843918 100644
--- a/shell/match.c
+++ b/shell/match.c
@@ -31,26 +31,23 @@ char *scanleft(char *string, char *pattern, bool match_at_left)
         char c;
         char *loc = string;
 
-        do {
+        while (1) {
                 int match;
-                const char *s;
 
                 c = *loc;
                 if (match_at_left) {
                         *loc = '\0';
-                        s = string;
-                } else
-                        s = loc;
-                match = pmatch(pattern, s);
-                *loc = c;
-
+                        match = pmatch(pattern, string);
+                        *loc = c;
+                } else {
+                        match = pmatch(pattern, loc);
+                }
                 if (match)
                         return loc;
-
+                if (!c)
+                        return NULL;
                 loc++;
-        } while (c);
-
-        return NULL;
+        }
 }
 
 char *scanright(char *string, char *pattern, bool match_at_left)
@@ -60,20 +57,17 @@ char *scanright(char *string, char *pattern, bool match_at_left)
 
         while (loc >= string) {
                 int match;
-                const char *s;
 
                 c = *loc;
                 if (match_at_left) {
                         *loc = '\0';
-                        s = string;
-                } else
-                        s = loc;
-                match = pmatch(pattern, s);
-                *loc = c;
-
+                        match = pmatch(pattern, string);
+                        *loc = c;
+                } else {
+                        match = pmatch(pattern, loc);
+                }
                 if (match)
                         return loc;
-
                 loc--;
         }