[gawk-diffs] [SCM] gawk branch, master, updated. fc9109734ddcf57c5f1faaedfadc432ec6841aa8

[Arnold Robbins]

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http://git.sv.gnu.org/cgit/gawk.git/commit/?id=fc9109734ddcf57c5f1faaedfadc432ec6841aa8

commit fc9109734ddcf57c5f1faaedfadc432ec6841aa8
Author: Arnold D. Robbins <address@hidden>
Date:   Fri Sep 14 00:16:48 2012 +0300

    Allow extensions read-only access to built-in vars.

diff --git a/ChangeLog b/ChangeLog
index 2598c30..d729027 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2012-09-14         Arnold D. Robbins     <address@hidden>
+
+       Allow read-only access to built-in variables from extensions.
+
+       * awk.h (NO_EXT_SET): New flag.
+       * gawkapi.c (api_sym_lookup, api_sym_update_real): Set flag if off
+       limits variable instead of failing. Adjust logic.
+       (api_sym_update_scalar, api_set_array_element, api_del_array_element,
+       api_release_flattened_array): Adjust logic.
+       * gawkapi.h: Adjust documentation.
+
 2012-09-13         Arnold D. Robbins     <address@hidden>
 
        * configure.ac: Determination of DYNAMIC adjusted. Hopefully is
diff --git a/awk.h b/awk.h
index de42529..b0208e5 100644
--- a/awk.h
+++ b/awk.h
@@ -447,6 +447,7 @@ typedef struct exp_node {
 #              define  WSTRCUR 0x0400       /* wide str value is current */
 #              define  MPFN    0x0800       /* arbitrary-precision 
floating-point number */
 #              define  MPZN    0x1000       /* arbitrary-precision integer */
+#              define  NO_EXT_SET 0x2000    /* extension cannot set a value 
for this variable */
 
 /* type = Node_var_array */
 #              define  ARRAYMAXED      0x2000       /* array is at max size */
diff --git a/extension/ChangeLog b/extension/ChangeLog
index 1a32961..2552a38 100644
--- a/extension/ChangeLog
+++ b/extension/ChangeLog
@@ -1,3 +1,9 @@
+2012-09-14         Arnold D. Robbins     <address@hidden>
+
+       * testext.c (try_modify_environ): New function and test.
+       (var_test): Modified ARGC test, added additional.
+       (test_scalar_reserved): New function and test.
+
 2012-09-13         Dave Pitts            <address@hidden>
 
        * gawkfts.c: Add defines and ifdefs for z/OS.
diff --git a/extension/testext.c b/extension/testext.c
index bb62fa0..c11a4c8 100644
--- a/extension/testext.c
+++ b/extension/testext.c
@@ -186,6 +186,101 @@ out:
 
 /*
 BEGIN {
+       ENVIRON["testext"]++
+       try_modify_environ()
+       if ("testext" in ENVIRON)
+               print "try_del_environ() could not delete element - pass"
+       else
+               print "try_del_environ() deleted element! - fail"
+       if ("testext2" in ENVIRON)
+               print "try_del_environ() added an element - fail"
+       else
+               print "try_del_environ() could not add an element - pass"
+}
+*/
+
+static awk_value_t *
+try_modify_environ(int nargs, awk_value_t *result)
+{
+       awk_value_t value, index, newvalue;
+       awk_flat_array_t *flat_array;
+       size_t count;
+       int i;
+
+       assert(result != NULL);
+       make_number(0.0, result);
+
+       if (nargs != 0) {
+               printf("try_modify_environ: nargs not right (%d should be 
0)\n", nargs);
+               goto out;
+       }
+
+       /* get ENVIRON array */
+       if (sym_lookup("ENVIRON", AWK_ARRAY, & value))
+               printf("try_modify_environ: sym_lookup of ENVIRON passed\n");
+       else {
+               printf("try_modify_environ: sym_lookup of ENVIRON failed\n");
+               goto out;
+       }
+
+       if (! get_element_count(value.array_cookie, & count)) {
+               printf("try_modify_environ: get_element_count failed\n");
+               goto out;
+       }
+
+       printf("try_modify_environ: incoming size is %lu\n", (unsigned long) 
count);
+
+       /* setting an array element should fail */
+       (void) make_const_string("testext2", 8, & index);
+       (void) make_const_string("a value", 7, & value);
+       if (set_array_element(value.array_cookie, & index, & newvalue)) {
+               printf("try_modify_environ: set_array_element of ENVIRON 
passed\n");
+       } else {
+               printf("try_modify_environ: set_array_element of ENVIRON 
failed\n");
+               free(index.str_value.str);
+               free(value.str_value.str);
+       }
+
+       if (! flatten_array(value.array_cookie, & flat_array)) {
+               printf("try_modify_environ: could not flatten array\n");
+               goto out;
+       }
+
+       if (flat_array->count != count) {
+               printf("try_modify_environ: flat_array->count (%lu) != count 
(%lu)\n",
+                               (unsigned long) flat_array->count,
+                               (unsigned long) count);
+               goto out;
+       }
+
+       for (i = 0; i < flat_array->count; i++) {
+               /* don't print */
+       /*
+               printf("\t%s[\"%.*s\"] = %s\n",
+                       name,
+                       (int) flat_array->elements[i].index.str_value.len,
+                       flat_array->elements[i].index.str_value.str,
+                       valrep2str(& flat_array->elements[i].value));
+       */
+               if (strcmp("testext", 
flat_array->elements[i].index.str_value.str) == 0) {
+                       flat_array->elements[i].flags |= AWK_ELEMENT_DELETE;
+                       printf("try_modify_environ: marking element \"%s\" for 
deletion\n",
+                               flat_array->elements[i].index.str_value.str);
+               }
+       }
+
+       if (! release_flattened_array(value.array_cookie, flat_array)) {
+               printf("try_modify_environ: could not release flattened 
array\n");
+               goto out;
+       }
+
+       make_number(1.0, result);
+out:
+       return result;
+}
+
+/*
+BEGIN {
        testvar = "One Adam Twelve"
        ret = var_test("testvar")
        printf "var_test() returned %d, test_var = %s\n", ret, testvar
@@ -207,11 +302,18 @@ var_test(int nargs, awk_value_t *result)
                goto out;
        }
 
-       /* look up a reserved variable - should fail */
+       /* look up a reserved variable - should pass */
        if (sym_lookup("ARGC", AWK_NUMBER, & value))
-               printf("var_test: sym_lookup of ARGC failed - got a value!\n");
+               printf("var_test: sym_lookup of ARGC passed - got a value!\n");
+       else
+               printf("var_test: sym_lookup of ARGC failed - did not get a 
value\n");
+
+       /* now try to set it - should fail */
+       value.num_value++;
+       if (sym_update("ARGC", & value))
+               printf("var_test: sym_update of ARGC passed and should not 
have!\n");
        else
-               printf("var_test: sym_lookup of ARGC passed - did not get a 
value\n");
+               printf("var_test: sym_update of ARGC failed - correctly\n");
 
        /* look up variable whose name is passed in, should pass */
        if (get_argument(0, AWK_STRING, & value)) {
@@ -535,6 +637,47 @@ test_scalar(int nargs, awk_value_t *result)
        }
 
        if (! sym_update_scalar(the_scalar.scalar_cookie, & new_value2)) {
+               printf("test_scalar: could not update new_value2!\n");
+               goto out;
+       }
+
+       make_number(1.0, result);
+
+out:
+       return result;
+}
+
+/*
+BEGIN {
+       test_scalar_reserved()
+}
+*/
+
+/* test_scalar_reserved --- test scalar cookie on special variable */
+
+static awk_value_t *
+test_scalar_reserved(int nargs, awk_value_t *result)
+{
+       awk_value_t new_value;
+       awk_value_t the_scalar;
+
+       make_number(0.0, result);
+
+       /* look up a reserved variable - should pass */
+       if (sym_lookup("ARGC", AWK_SCALAR, & the_scalar)) {
+               printf("test_scalar_reserved: sym_lookup of ARGC passed - got a 
value!\n");
+       } else {
+               printf("test_scalar_reserved: sym_lookup of ARGC failed - did 
not get a value\n");
+               goto out;
+       }
+
+       /* updating it should fail */
+       make_number(42.0, & new_value);
+       if (! sym_update_scalar(the_scalar.scalar_cookie, & new_value)) {
+               printf("test_scalar_reserved: could not update new_value2 for 
ARGC - pass\n");
+       } else {
+               printf("test_scalar_reserved: was able to update new_value2 for 
ARGC - fail\n");
+               goto out;
        }
 
        make_number(1.0, result);
@@ -628,6 +771,7 @@ static void at_exit2(void *data, int exit_status)
 
 static awk_ext_func_t func_table[] = {
        { "dump_array_and_delete", dump_array_and_delete, 2 },
+       { "try_modify_environ", try_modify_environ, 0 },
        { "var_test", var_test, 1 },
        { "test_errno", test_errno, 0 },
        { "test_array_size", test_array_size, 1 },
@@ -635,6 +779,7 @@ static awk_ext_func_t func_table[] = {
        { "test_array_param", test_array_param, 1 },
        { "print_do_lint", print_do_lint, 0 },
        { "test_scalar", test_scalar, 1 },
+       { "test_scalar_reserved", test_scalar_reserved, 0 },
 };
 
 /* init_testext --- additional initialization function */
diff --git a/gawkapi.c b/gawkapi.c
index 5d372bb..dbb8549 100644
--- a/gawkapi.c
+++ b/gawkapi.c
@@ -489,10 +489,12 @@ api_sym_lookup(awk_ext_id_t id,
        if (   name == NULL
            || *name == '\0'
            || result == NULL
-           || is_off_limits_var(name)  /* most built-in vars not allowed */
            || (node = lookup(name)) == NULL)
                return false;
 
+       if (is_off_limits_var(name))    /* a built-in variable */
+               node->flags |= NO_EXT_SET;
+
        return node_to_awk_value(node, result, wanted);
 }
 
@@ -527,7 +529,6 @@ sym_update_real(awk_ext_id_t id,
 
        if (   name == NULL
            || *name == '\0'
-           || is_off_limits_var(name)  /* most built-in vars not allowed */
            || value == NULL)
                return false;
 
@@ -573,6 +574,12 @@ sym_update_real(awk_ext_id_t id,
         * If we get here, then it exists already.  Any valid type is
         * OK except for AWK_ARRAY.
         */
+       if (   (node->flags & NO_EXT_SET) != 0
+           || is_off_limits_var(name)) {       /* most built-in vars not 
allowed */
+               node->flags |= NO_EXT_SET;
+               return false;
+       }
+
        if (    value->val_type != AWK_ARRAY
            && (node->type == Node_var || node->type == Node_var_new)) {
                unref(node->var_value);
@@ -618,7 +625,8 @@ api_sym_update_scalar(awk_ext_id_t id,
 
        if (value == NULL
            || node == NULL
-           || node->type != Node_var)
+           || node->type != Node_var
+           || (node->flags & NO_EXT_SET) != 0)
                return false;
 
        /*
@@ -766,6 +774,7 @@ api_set_array_element(awk_ext_id_t id, awk_array_t a_cookie,
        /* don't check for index len zero, null str is ok as index */
        if (   array == NULL
            || array->type != Node_var_array
+           || (array->flags & NO_EXT_SET) != 0
            || index == NULL
            || value == NULL
            || ! valid_subscript_type(index->val_type))
@@ -825,6 +834,7 @@ api_del_array_element(awk_ext_id_t id,
        array = (NODE *) a_cookie;
        if (   array == NULL
            || array->type != Node_var_array
+           || (array->flags & NO_EXT_SET) != 0
            || index == NULL
            || ! valid_subscript_type(index->val_type))
                return false;
@@ -957,7 +967,8 @@ api_release_flattened_array(awk_ext_id_t id,
        /* free index nodes */
        for (i = j = 0, k = 2 * array->table_size; i < k; i += 2, j++) {
                /* Delete items flagged for delete. */
-               if ((data->elements[j].flags & AWK_ELEMENT_DELETE) != 0) {
+               if (   (data->elements[j].flags & AWK_ELEMENT_DELETE) != 0
+                   && (array->flags & NO_EXT_SET) == 0) {
                        remove_element(array, list[i]);
                }
                unref(list[i]);
diff --git a/gawkapi.h b/gawkapi.h
index 95effd9..e8b7ebf 100644
--- a/gawkapi.h
+++ b/gawkapi.h
@@ -447,8 +447,8 @@ typedef struct gawk_api {
         * or if the wrong type was requested.
         * In the latter case, fills in vaule->val_type with the real type,
         * as described above.
-        * Built-in variables (except PROCINFO) may not be accessed by an
-        * extension.
+        * Built-in variables may be accessed by an extension, but, with
+        * the exception of PROCINFO, they may not be modified.
         *
         *      awk_value_t val;
         *      if (! api->sym_lookup(id, name, wanted, & val))
@@ -495,13 +495,15 @@ typedef struct gawk_api {
         * Flow is
         *      sym_lookup with wanted == AWK_SCALAR
         *      if returns false
-        *              sym_update with real initial value
+        *              sym_update with real initial value to install it
         *              sym_lookup again with AWK_SCALAR
         *      else
         *              use the scalar cookie
         *
         * Return will be false if the new value is not one of
         * AWK_STRING or AWK_NUMBER.
+        *
+        * Here too, the built-in variables may not be updated.
         */
        awk_bool_t (*api_sym_update_scalar)(awk_ext_id_t id,
                                awk_scalar_t cookie, awk_value_t *value);
@@ -522,6 +524,8 @@ typedef struct gawk_api {
        /*
         * Change (or create) element in existing array with
         * element->index and element->value.
+        *
+        * ARGV and ENVIRON may not be updated.
         */
        awk_bool_t (*api_set_array_element)(awk_ext_id_t id, awk_array_t 
a_cookie,
                                        const awk_value_t *const index,
diff --git a/test/ChangeLog b/test/ChangeLog
index ff99236..4bab479 100644
--- a/test/ChangeLog
+++ b/test/ChangeLog
@@ -1,3 +1,7 @@
+2012-09-14         Arnold D. Robbins     <address@hidden>
+
+       * testext.ok: Updated.
+
 2012-09-11         Arnold D. Robbins     <address@hidden>
 
        * Makefile.am (shlib-tests): Check if DYNAMIC is enabled and
diff --git a/test/testext.ok b/test/testext.ok
index 132179c..d291f72 100644
--- a/test/testext.ok
+++ b/test/testext.ok
@@ -10,7 +10,14 @@ dump_array_and_delete: marking element "3" for deletion
 dump_array_and_delete(pets) returned 1
 dump_array_and_delete() did remove index "3"!
 
-var_test: sym_lookup of ARGC passed - did not get a value
+try_modify_environ: sym_lookup of ENVIRON passed
+try_modify_environ: incoming size is 60
+try_modify_environ: set_array_element of ENVIRON failed
+try_modify_environ: could not flatten array
+try_del_environ() could not delete element - pass
+try_del_environ() could not add an element - pass
+var_test: sym_lookup of ARGC passed - got a value!
+var_test: sym_update of ARGC failed - correctly
 var_test: sym_update("testvar") succeeded
 var_test() returned 1, test_var = 42
 
@@ -57,6 +64,8 @@ test_scalar(over) returned 1, the_scalar is over
 test_scalar(the) returned 1, the_scalar is the
 test_scalar(lazy) returned 1, the_scalar is lazy
 test_scalar(dog) returned 1, the_scalar is dog
+test_scalar_reserved: sym_lookup of ARGC passed - got a value!
+test_scalar_reserved: could not update new_value2 for ARGC - pass
 answer_num = 42
 message_string = hello, world
 new_array["hello"] = "world"

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog           |   11 ++++
 awk.h               |    1 +
 extension/ChangeLog |    6 ++
 extension/testext.c |  151 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 gawkapi.c           |   19 +++++--
 gawkapi.h           |   10 +++-
 test/ChangeLog      |    4 ++
 test/testext.ok     |   11 ++++-
 8 files changed, 202 insertions(+), 11 deletions(-)


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