awk: make -F STR interpret escape sequences. Closes 5126

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

2 files changed, 24 insertions, 7 deletions

diff --git a/editors/awk.c b/editors/awk.c
index 71abca215..d69720d64 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -696,6 +696,10 @@ static char nextchar(char **s)
         pps = *s;
         if (c == '\\')
                 c = bb_process_escape_sequence((const char**)s);
+        /* Example awk statement:
+         * s = "abc\"def"
+         * we must treat \" as "
+         */
         if (c == '\\' && *s == pps) { /* unrecognized \z? */
                 c = *(*s); /* yes, fetch z */
                 if (c)
@@ -704,6 +708,15 @@ static char nextchar(char **s)
         return c;
 }
 
+/* TODO: merge with strcpy_and_process_escape_sequences()?
+ */
+static void unescape_string_in_place(char *s1)
+{
+        char *s = s1;
+        while ((*s1 = nextchar(&s)) != '\0')
+                s1++;
+}
+
 static ALWAYS_INLINE int isalnum_(int c)
 {
         return (isalnum(c) || c == '_');
@@ -2992,7 +3005,7 @@ static int awk_exit(int r)
  * otherwise return 0 */
 static int is_assignment(const char *expr)
 {
-        char *exprc, *val, *s, *s1;
+        char *exprc, *val;
 
         if (!isalnum_(*expr) || (val = strchr(expr, '=')) == NULL) {
                 return FALSE;
@@ -3002,10 +3015,7 @@ static int is_assignment(const char *expr)
         val = exprc + (val - expr);
         *val++ = '\0';
 
-        s = s1 = val;
-        while ((*s1 = nextchar(&s)) != '\0')
-                s1++;
-
+        unescape_string_in_place(val);
         setvar_u(newvar(exprc), val);
         free(exprc);
         return TRUE;
@@ -3118,8 +3128,10 @@ int awk_main(int argc, char **argv)
         opt = getopt32(argv, "F:v:f:W:", &opt_F, &list_v, &list_f, NULL);
         argv += optind;
         argc -= optind;
-        if (opt & 0x1)
-                setvar_s(intvar[FS], opt_F); // -F
+        if (opt & 0x1) { /* -F */
+                unescape_string_in_place(opt_F);
+                setvar_s(intvar[FS], opt_F);
+        }
         while (list_v) { /* -v */
                 if (!is_assignment(llist_pop(&list_v)))
                         bb_show_usage();
diff --git a/testsuite/awk.tests b/testsuite/awk.tests
index e67190757..d4c390d31 100755
--- a/testsuite/awk.tests
+++ b/testsuite/awk.tests
@@ -43,6 +43,11 @@ testing "awk long field sep" "awk -F-- '{ print NF, length(\$NF), \$NF }'" \
         "" \
         "a--\na--b--\na--b--c--\na--b--c--d--"
 
+testing "awk -F handles escapes" "awk -F'\\x21' '{print \$1}'" \
+        "a\n" \
+        "" \
+        "a!b\n"
+
 # '@(samp|code|file)\{' is an invalid extended regex (unmatched '{'),
 # but gawk 3.1.5 does not bail out on it.
 testing "awk gsub falls back to non-extended-regex" \