X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Fsrc%2Fpalacios%2Fvmm_xml.c;h=a9c66592501e611773dbc59cb796c43deaebf43c;hb=210c49c1f9b523ff94fd5b6791961d242d5bbae4;hp=f3641be5159ccec1e99b0dab094869a6df52b1d5;hpb=1f7a670397e97ea1028294d7b7b45d6ef1797d65;p=palacios.git

diff --git a/palacios/src/palacios/vmm_xml.c b/palacios/src/palacios/vmm_xml.c
index f3641be..a9c6659 100644
--- a/palacios/src/palacios/vmm_xml.c
+++ b/palacios/src/palacios/vmm_xml.c
@@ -41,6 +41,8 @@
 #define V3_XML_DUP     0x20 // attribute name and value are strduped
 //
 
+static char * V3_XML_NIL[] = { NULL }; // empty, null terminated array of strings
+
 
 #define V3_XML_WS   "\t\r\n "  // whitespace
 #define V3_XML_ERRL 128        // maximum error string length
@@ -51,38 +53,35 @@ struct v3_xml_root {       // additional data for the root tag
     char *str_ptr;         // original xml string
     char *tmp_start;              // start of work area
     char *tmp_end;              // end of work area
-    char **ent;           // general entities (ampersand sequences)
-    char ***attr;         // default attributes
     short standalone;     // non-zero if <?xml standalone="yes"?>
-    char err[V3_XML_ERRL]; // error string
 };
 
 static char * empty_attrib_list[] = { NULL }; // empty, null terminated array of strings
 
 
-static void * tmp_realloc(void * old_ptr, uint_t old_size, uint_t new_size) {
-    void * new_buf = V3_Malloc(new_size);
 
+static void * tmp_realloc(void * old_ptr, size_t old_size, size_t new_size) {
+    void * new_buf = NULL; 
+
+    new_buf = V3_Malloc(new_size);
+    
     if (new_buf == NULL) {
+	PrintError(VM_NONE, VCORE_NONE, "Cannot allocate in tmp_realloc in xml\n");
         return NULL;
     }
 
+    memset(new_buf, 0, new_size);
+
     memcpy(new_buf, old_ptr, old_size);
     V3_Free(old_ptr);
 
     return new_buf;
 }
 
-
-
-
-
 // set an error string and return root
-static void v3_xml_err(struct v3_xml_root * root, char * xml_str, const char * err, ...) {
-    va_list ap;
+static void v3_xml_err(struct v3_xml_root * root, char * xml_str, const char * err, const char *arg) {
     int line = 1;
     char * tmp;
-    char fmt[V3_XML_ERRL];
     
     for (tmp = root->tmp_start; tmp < xml_str; tmp++) {
 	if (*tmp == '\n') {
@@ -90,14 +89,8 @@ static void v3_xml_err(struct v3_xml_root * root, char * xml_str, const char * e
 	}
     }
 
-    snprintf(fmt, V3_XML_ERRL, "[error near line %d]: %s", line, err);
-
-    va_start(ap, err);
-    vsnprintf(root->err, V3_XML_ERRL, fmt, ap);
-    va_end(ap);
-
-    PrintError("XML Error: %s\n", root->err);
-
+    PrintError(VM_NONE, VCORE_NONE, "XML Error: [error near line %d]: %s (%s)", line, err ,arg ? arg : "");
+    
     // free memory
     v3_xml_free(&(root->xml));
 
@@ -134,8 +127,6 @@ struct v3_xml * v3_xml_idx(struct v3_xml * xml, int idx) {
 // returns the value of the requested tag attribute or NULL if not found
 const char * v3_xml_attr(struct v3_xml * xml, const char * attr) {
     int i = 0;
-    int j = 1;
-    struct v3_xml_root * root = (struct v3_xml_root *)xml;
 
     if ((!xml) || (!xml->attr)) {
 	return NULL;
@@ -149,59 +140,18 @@ const char * v3_xml_attr(struct v3_xml * xml, const char * attr) {
 	return xml->attr[i + 1]; // found attribute
     }
 
-    while (root->xml.parent != NULL) {
-	root = (struct v3_xml_root *)root->xml.parent; // root tag
-    }
-
-    for (i = 0; 
-	 ( (root->attr[i] != NULL) && 
-	   (strcasecmp(xml->name, root->attr[i][0]) != 0) ); 
-	 i++);
-
-    if (! root->attr[i]) {
-	return NULL; // no matching default attributes
-    }
-
-    while ((root->attr[i][j] != NULL) && (strcasecmp(attr, root->attr[i][j]) != 0)) {
-	j += 3;
-    }
-
-    return (root->attr[i][j] != NULL) ? root->attr[i][j + 1] : NULL; // found default
+    return NULL; // found default
 }
 
-// same as v3_xml_get but takes an already initialized va_list
-static struct v3_xml * v3_xml_vget(struct v3_xml * xml, va_list ap) {
-    char * name = va_arg(ap, char *);
-    int idx = -1;
 
-    if ((name != NULL) && (*name != 0)) {
-        idx = va_arg(ap, int);    
-        xml = v3_xml_child(xml, name);
-    }
-    return (idx < 0) ? xml : v3_xml_vget(v3_xml_idx(xml, idx), ap);
-}
-
-// Traverses the xml tree to retrieve a specific subtag. Takes a variable
-// length list of tag names and indexes. The argument list must be terminated
-// by either an index of -1 or an empty string tag name. Example: 
-// title = v3_xml_get(library, "shelf", 0, "book", 2, "title", -1);
-// This retrieves the title of the 3rd book on the 1st shelf of library.
-// Returns NULL if not found.
-struct v3_xml * v3_xml_get(struct v3_xml * xml, ...) {
-    va_list ap;
-    struct v3_xml * r;
-
-    va_start(ap, xml);
-    r = v3_xml_vget(xml, ap);
-    va_end(ap);
-    return r;
-}
 
 
 // sets a flag for the given tag and returns the tag
 static struct v3_xml * v3_xml_set_flag(struct v3_xml * xml, short flag)
 {
-    if (xml) xml->flags |= flag;
+    if (xml) {
+	xml->flags |= flag;
+    }
     return xml;
 }
 
@@ -215,11 +165,10 @@ static struct v3_xml * v3_xml_set_flag(struct v3_xml * xml, short flag)
 // for cdata sections, ' ' for attribute normalization, or '*' for non-cdata
 // attribute normalization. Returns s, or if the decoded string is longer than
 // s, returns a malloced string that must be freed.
-static char * v3_xml_decode(char * s, char ** ent, char t) {
+static char * v3_xml_decode(char * s, char t) {
     char * e;
     char * r = s;
-    char * m = s;
-    long b, c, d, l;
+    long c, l;
 
     // normalize line endings
     for (; *s; s++) { 
@@ -262,28 +211,6 @@ static char * v3_xml_decode(char * s, char ** ent, char t) {
 	    *(s++) = c; 
 
             memmove(s, strchr(s, ';') + 1, strlen(strchr(s, ';')));
-        } else if ( ( (*s == '&') && 
-		      ((t == '&') || (t == ' ') || (t == '*'))) ||
-		    ( (*s == '%') && (t == '%'))) { 
-	    // entity reference`
-
-            for ( (b = 0); 
-		  (ent[b]) && (strncmp(s + 1, ent[b], strlen(ent[b])) != 0);
-		  (b += 2)); // find entity in entity list
-
-            if (ent[b++]) { // found a match
-                if (((c = strlen(ent[b])) - 1) > ((e = strchr(s, ';')) - s)) {
-                    l = (d = (s - r)) + c + strlen(e); // new length
-                    r = ((r == m) ? strcpy(V3_Malloc(l), r) : tmp_realloc(r, strlen(r), l));
-                    e = strchr((s = r + d), ';'); // fix up pointers
-                }
-
-                memmove(s + c, e + 1, strlen(e)); // shift rest of string
-                strncpy(s, ent[b], c); // copy in replacement text
-            } else {
-		// not a known entity
-		s++;
-	    }
         } else if ( ( (t == ' ') || (t == '*')) && 
 		    (isspace(*s))) {
 	    *(s++) = ' ';
@@ -327,16 +254,29 @@ static void v3_xml_char_content(struct v3_xml_root * root, char * s, size_t len,
     }
 
     s[len] = '\0'; // null terminate text (calling functions anticipate this)
-    len = strlen(s = v3_xml_decode(s, root->ent, t)) + 1;
+    len = strlen(s = v3_xml_decode(s, t)) + 1;
 
-    if (! *(xml->txt)) {
+    if (xml->txt[0] == '\0') { // empty string
 	// initial character content
 	xml->txt = s;
     } else { 
+
 	// allocate our own memory and make a copy
-        xml->txt = (xml->flags & V3_XML_TXTM) ? 
-	    (tmp_realloc(xml->txt, strlen(xml->txt), (l = strlen(xml->txt)) + len)) : 
-	    (strcpy(V3_Malloc((l = strlen(xml->txt)) + len), xml->txt));
+	if (xml->flags & V3_XML_TXTM) {
+	    xml->txt = (tmp_realloc(xml->txt, strlen(xml->txt), (l = strlen(xml->txt)) + len));
+	} else {
+	    char * tmp = NULL;
+
+	    tmp = V3_Malloc((l = strlen(xml->txt)) + len);
+
+	    if (!tmp) {
+		PrintError(VM_NONE, VCORE_NONE, "Cannot allocate in xml char content\n");
+		return ;
+	    }
+
+	    strcpy(tmp, xml->txt);
+	    xml->txt = tmp;
+	}
 
         strcpy(xml->txt + l, s); // add new char content
 	
@@ -355,7 +295,7 @@ static int v3_xml_close_tag(struct v3_xml_root * root, char * name, char * s) {
     if ( (root->cur == NULL) || 
 	 (root->cur->name == NULL) || 
 	 (strcasecmp(name, root->cur->name))) {
-	v3_xml_err(root, s, "unexpected closing tag </%s>", name);
+	v3_xml_err(root, s, "unexpected closing tag", name);
 	return -1;
     }
 
@@ -363,37 +303,6 @@ static int v3_xml_close_tag(struct v3_xml_root * root, char * name, char * s) {
     return 0;
 }
 
-#if 0
-// checks for circular entity references, returns non-zero if no circular
-// references are found, zero otherwise
-static int v3_xml_ent_ok(char * name, char * s, char ** ent) {
-    int i;
-
-    for (; ; s++) {
-        while ((*s != '\0') && (*s != '&')) {
-	    // find next entity reference
-	    s++; 
-	}
-
-        if (*s == '\0') {
-	    return 1;
-	}
-
-        if (strncmp(s + 1, name, strlen(name)) == 0) {
-	    // circular ref.
-	    return 0;
-	}
-
-        for (i = 0; (ent[i]) && (strncmp(ent[i], s + 1, strlen(ent[i]))); i += 2);
-
-        if ((ent[i] != NULL) && (v3_xml_ent_ok(name, ent[i + 1], ent) == 0)) {
-	    return 0;
-	}
-    }
-}
-#endif
-
-
 
 // frees a tag attribute list
 static void v3_xml_free_attr(char **attr) {
@@ -412,16 +321,6 @@ static void v3_xml_free_attr(char **attr) {
 
     m = attr[i + 1]; // list of which names and values are malloced
 
-    for (i = 0; m[i]; i++) {
-        if (m[i] & V3_XML_NAMEM) {
-	    V3_Free(attr[i * 2]);
-	}
-
-        if (m[i] & V3_XML_TXTM) {
-	    V3_Free(attr[(i * 2) + 1]);
-	}
-    }
-
     V3_Free(m);
     V3_Free(attr);
 }
@@ -433,28 +332,26 @@ static void v3_xml_free_attr(char **attr) {
 
 // returns a new empty v3_xml structure with the given root tag name
 static struct v3_xml * v3_xml_new(const char * name) {
-    static char * ent[] = { "lt;", "&#60;", "gt;", "&#62;", "quot;", "&#34;",
-                           "apos;", "&#39;", "amp;", "&#38;", NULL };
 
     struct v3_xml_root * root = (struct v3_xml_root *)V3_Malloc(sizeof(struct v3_xml_root));
+
+    if (!root) {
+	PrintError(VM_NONE, VCORE_NONE, "Cannot allocate in xml_new\n");
+	return NULL;
+    }
+
     memset(root, 0, sizeof(struct v3_xml_root));
 
     root->xml.name = (char *)name;
     root->cur = &root->xml;
     root->xml.txt = "";
-    memset(root->err, 0, V3_XML_ERRL);
 
-    root->ent = V3_Malloc(sizeof(ent));
-    memcpy(root->ent, ent, sizeof(ent));
-
-    root->xml.attr = empty_attrib_list;
-    root->attr = (char ***)(empty_attrib_list);
 
     return &root->xml;
 }
 
 // inserts an existing tag into an v3_xml structure
-static struct v3_xml * v3_xml_insert(struct v3_xml * xml, struct v3_xml * dest, size_t off) {
+struct v3_xml * v3_xml_insert(struct v3_xml * xml, struct v3_xml * dest, size_t off) {
     struct v3_xml * cur, * prev, * head;
 
     xml->next = NULL;
@@ -537,6 +434,12 @@ static struct v3_xml * v3_xml_add_child(struct v3_xml * xml, const char * name,
     }
 
     child = (struct v3_xml *)V3_Malloc(sizeof(struct v3_xml));
+
+    if (!child) {
+	PrintError(VM_NONE, VCORE_NONE, "Cannot allocate in xml_add_child\n");
+	return NULL;
+    }
+
     memset(child, 0, sizeof(struct v3_xml));
 
     child->name = (char *)name;
@@ -575,14 +478,20 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
     char last_char; 
     char * tag_ptr;
     char ** attr; 
-    char ** tmp_attr = NULL; // initialize a to avoid compile warning
     int attr_idx;
-    int i, j;
+
+    if (buf==NULL) {
+      return NULL;
+    }
+
+    if (root==NULL) {
+      return NULL;
+    }
 
     root->str_ptr = buf;
 
     if (len == 0) {
-	v3_xml_err(root, NULL, "Empty XML String\n");
+	v3_xml_err(root, NULL, "Empty XML String", 0);
 	return NULL;
     }
 
@@ -598,7 +507,7 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
     }
 
     if (*buf == '\0') {
-	v3_xml_err(root, buf, "root tag missing");
+	v3_xml_err(root, buf, "root tag missing", 0);
 	return NULL;
     }
 
@@ -610,7 +519,7 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
 	    // new tag
 
             if (root->cur == NULL) {
-                v3_xml_err(root, tag_ptr, "markup outside of root element");
+                v3_xml_err(root, tag_ptr, "markup outside of root element", 0);
 		return NULL;
 	    }
 
@@ -622,17 +531,7 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
 		*(buf++) = '\0';
 	    }
 
-	    // check if attribute follows tag
-            if ((*buf) && (*buf != '/') && (*buf != '>')) {
-		// there is an attribute
-		// find attributes for correct tag
-                for ((i = 0); 
-		     ((tmp_attr = root->attr[i]) && 
-		      (strcasecmp(tmp_attr[0], tag_ptr) != 0)); 
-		     (i++)) ;
-		
-		// 'tmp_attr' now points to the attribute list associated with 'tag_ptr'
-	    }
+	
 
 	    // attributes are name value pairs, 
 	    //     2nd to last entry is null  (end of list)
@@ -656,15 +555,33 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
 					(2 * sizeof(char *))), 
 				       ((attr_cnt * (2 * sizeof(char *))) + 
 					(2 * sizeof(char *))));
-		
+
+		    if (!attr) {
+			PrintError(VM_NONE, VCORE_NONE, "Cannot reallocate in xml parse string\n");
+			return NULL;
+		    }
+
 		    attr[last_idx] = tmp_realloc(attr[last_idx - 2], 
 						 attr_cnt,
 						 (attr_cnt + 1)); 
+
+		    if (!attr[last_idx]) {
+			PrintError(VM_NONE, VCORE_NONE, "Cannot reallocate in xml parse string\n");
+			return NULL;
+		    }
+
 		} else {
 		    attr = V3_Malloc(4 * sizeof(char *)); 
+		    if (!attr) {
+			PrintError(VM_NONE, VCORE_NONE, "Cannot allocate in xml parse string\n");
+			return NULL;
+		    }
 		    attr[last_idx] = V3_Malloc(2);
+		    if (!attr[last_idx]) {
+			PrintError(VM_NONE, VCORE_NONE, "Cannot alloocate in xml parse string\n");
+			return NULL;
+		    }
 		}
-		
 
                 attr[attr_idx] = buf; // set attribute name
                 attr[val_idx] = ""; // temporary attribute value
@@ -674,9 +591,9 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
                 buf += strcspn(buf, V3_XML_WS "=/>");
 
                 if ((*buf == '=') || isspace(*buf)) {
-                    
+
 		    *(buf++) = '\0'; // null terminate tag attribute name
-		    
+
 		    // eat whitespace (and more multiple '=' ?)
 		    buf += strspn(buf, V3_XML_WS "=");
 
@@ -693,25 +610,14 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
 			    // null terminate attribute val
 			    *(buf++) = '\0';
 			} else {
+			    char err_buf[2] = {quote_char,0};
+
                             v3_xml_free_attr(attr);
-                            v3_xml_err(root, tag_ptr, "missing %c", quote_char);
+                            v3_xml_err(root, tag_ptr, "missing quote char", err_buf);
 			    return NULL;
                         }
 
-                        for (j = 1; 
-			     ( (tmp_attr) && (tmp_attr[j]) && 
-			       (strcasecmp(tmp_attr[j], attr[attr_idx]) != 0)); 
-			     j += 3);
-
-                        attr[val_idx] = v3_xml_decode(attr[val_idx], root->ent, 
-						      ((tmp_attr && tmp_attr[j]) ? 
-						       *tmp_attr[j + 2] : 
-						       ' '));
-			
-                        if ( (attr[val_idx] < tag_ptr) || 
-			     (attr[val_idx] > buf) ) {
-                            attr[last_idx][attr_cnt - 1] = V3_XML_TXTM; // value malloced
-			}
+                        attr[val_idx] = v3_xml_decode(attr[val_idx], ' ');
                     }
                 }
 
@@ -730,7 +636,7 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
                     if (attr_idx > 0) {
 			v3_xml_free_attr(attr);
 		    }
-		    v3_xml_err(root, tag_ptr, "missing >");
+		    v3_xml_err(root, tag_ptr, "missing >", 0);
 		    return NULL;
                 }
                 v3_xml_open_tag(root, tag_ptr, attr);
@@ -745,7 +651,7 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
                 if (attr_idx > 0) {
 		    v3_xml_free_attr(attr);
 		}
-		v3_xml_err(root, tag_ptr, "missing >"); 
+		v3_xml_err(root, tag_ptr, "missing >", 0); 
 		return NULL;
             }
         } else if (*buf == '/') { 
@@ -755,7 +661,7 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
             
 	    quote_char = *buf;
 	    if ((*buf == '\0') && (last_char != '>')) {
-		v3_xml_err(root, tag_ptr, "missing >");
+		v3_xml_err(root, tag_ptr, "missing >", 0);
 		return NULL;
             }
 
@@ -774,7 +680,7 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
             if ( ((buf = strstr(buf + 3, "--")) == 0) || 
 		 ((*(buf += 2) != '>') && (*buf)) ||
 		 ((!*buf) && (last_char != '>'))) {
-		v3_xml_err(root, tag_ptr, "unclosed <!--");
+		v3_xml_err(root, tag_ptr, "unclosed <!--", 0);
 		return NULL;
 	    }
         } else if (! strncmp(buf, "![CDATA[", 8)) { 
@@ -782,21 +688,27 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
             if ((buf = strstr(buf, "]]>"))) {
                 v3_xml_char_content(root, tag_ptr + 8, (buf += 2) - tag_ptr - 10, 'c');
 	    } else {
-		v3_xml_err(root, tag_ptr, "unclosed <![CDATA[");
+		v3_xml_err(root, tag_ptr, "unclosed <![CDATA[", 0);
 		return NULL;
 	    }
 	} else {
-	    v3_xml_err(root, tag_ptr, "unexpected <");
+	    v3_xml_err(root, tag_ptr, "unexpected <",0);
 	    return NULL;
         }
 
-        if (! buf || ! *buf) {
+	// at this point, buf cannot be NULL
+        if (!*buf) {
 	    break;
 	}
 
         *buf = '\0';
         tag_ptr = ++buf;
 
+	/* Eat leading whitespace */
+	while (*buf && isspace(*buf)) {
+	    buf++;
+	}
+
         if (*buf && (*buf != '<')) { 
 	    // tag character content
             while (*buf && (*buf != '<')) {
@@ -816,10 +728,10 @@ static struct v3_xml * parse_str(char * buf, size_t len) {
     if (root->cur == NULL) {
 	return &root->xml;
     } else if (root->cur->name == NULL) {
-	v3_xml_err(root, tag_ptr, "root tag missing");
+	v3_xml_err(root, tag_ptr, "root tag missing",0);
 	return NULL;
     } else {
-	v3_xml_err(root, tag_ptr, "unclosed tag <%s>", root->cur->name);
+	v3_xml_err(root, tag_ptr, "unclosed tag", root->cur->name);
 	return NULL;
     }
 }
@@ -835,6 +747,12 @@ struct v3_xml * v3_xml_parse(char * buf) {
 
     str_len = strlen(buf);
     xml_buf = (char *)V3_Malloc(str_len + 1);
+
+    if (!xml_buf) {
+	PrintError(VM_NONE, VCORE_NONE, "Cannot allocate in xml parse\n");
+	return NULL;
+    }
+
     strcpy(xml_buf, buf);
 
     return parse_str(xml_buf, str_len);
@@ -845,8 +763,6 @@ struct v3_xml * v3_xml_parse(char * buf) {
 // free the memory allocated for the v3_xml structure
 void v3_xml_free(struct v3_xml * xml) {
     struct v3_xml_root * root = (struct v3_xml_root *)xml;
-    int i, j;
-    char **a, *s;
 
     if (xml == NULL) {
         return;
@@ -857,46 +773,349 @@ void v3_xml_free(struct v3_xml * xml) {
 
     if (xml->parent == NULL) { 
 	// free root tag allocations
+	V3_Free(root->str_ptr); // malloced xml data
+    }
+
+    v3_xml_free_attr(xml->attr); // tag attributes
+
+
+
+    if ((xml->flags & V3_XML_TXTM)) {
+	// character content
+	V3_Free(xml->txt); 
+    }
+
+    if ((xml->flags & V3_XML_NAMEM)) {
+	// tag name
+	V3_Free(xml->name);
+    }
+
+    V3_Free(xml);
+}
+
+
+
+
+
+/* Adding XML data */
+
+
+
+
+// sets the character content for the given tag and returns the tag
+struct v3_xml *  v3_xml_set_txt(struct v3_xml * xml, const char *txt) {
+    if (! xml) {
+	return NULL;
+    }
+
+    if (xml->flags & V3_XML_TXTM) {
+	// existing txt was malloced
+	V3_Free(xml->txt); 
+    }
+
+    xml->flags &= ~V3_XML_TXTM;
+    xml->txt = (char *)txt;
+    return xml;
+}
+
+// Sets the given tag attribute or adds a new attribute if not found. A value
+// of NULL will remove the specified attribute. Returns the tag given.
+struct v3_xml * v3_xml_set_attr(struct v3_xml * xml, const char * name, const char * value) {
+    int l = 0;
+    int c;
+
+    if (! xml) {
+	return NULL;
+    }
+
+    while (xml->attr[l] && strcmp(xml->attr[l], name)) {
+	l += 2;
+    }
+
+    if (! xml->attr[l]) { 
+	// not found, add as new attribute
         
-	for (i = 10; root->ent[i]; i += 2) {
-	    // 0 - 9 are default entites (<>&"')
-            if ((s = root->ent[i + 1]) < root->tmp_start || s > root->tmp_end) {
-		V3_Free(s);
+	if (! value) {
+	    // nothing to do
+	    return xml;
+	}
+       
+	if (xml->attr == V3_XML_NIL) { 
+	    // first attribute
+            xml->attr = V3_Malloc(4 * sizeof(char *));
+
+	    if (!xml->attr) {
+		PrintError(VM_NONE, VCORE_NONE, "Cannot allocate in xml set attr\n");
+		return NULL;
+	    }
+
+	    // empty list of malloced names/vals
+            xml->attr[1] = strdup(""); 
+
+	    if (!xml->attr[1]) {
+		PrintError(VM_NONE, VCORE_NONE, "Cannot strdup in xml set attr\n");
+		return NULL;
 	    }
+
+        } else {
+	    xml->attr = tmp_realloc(xml->attr, l * sizeof(char *), (l + 4) * sizeof(char *));
+
+	    if (!xml->attr) {
+		PrintError(VM_NONE, VCORE_NONE, "Cannot reallocate in xml set attr\n");
+		return NULL;
+	    }
+	}
+
+	// set attribute name
+        xml->attr[l] = (char *)name; 
+
+	// null terminate attribute list
+        xml->attr[l + 2] = NULL; 
+
+        xml->attr[l + 3] = tmp_realloc(xml->attr[l + 1],
+				       strlen(xml->attr[l + 1]),
+				       (c = strlen(xml->attr[l + 1])) + 2);
+
+
+	if (!xml->attr[l + 3]) {
+	    PrintError(VM_NONE, VCORE_NONE, "Cannot reallocate in xml set attr\n");
+	    return NULL;
+	}
+
+	// set name/value as not malloced
+        strcpy(xml->attr[l + 3] + c, " "); 
+
+        if (xml->flags & V3_XML_DUP) {
+	    xml->attr[l + 3][c] = V3_XML_NAMEM;
+	}
+    } else if (xml->flags & V3_XML_DUP) {
+	// name was strduped
+	V3_Free((char *)name); 
+    }
+
+
+    // find end of attribute list
+    for (c = l; xml->attr[c]; c += 2); 
+
+    if (xml->attr[c + 1][l / 2] & V3_XML_TXTM) {
+	//old val
+	V3_Free(xml->attr[l + 1]); 
+    }
+
+    if (xml->flags & V3_XML_DUP) {
+	xml->attr[c + 1][l / 2] |= V3_XML_TXTM;
+    } else {
+	xml->attr[c + 1][l / 2] &= ~V3_XML_TXTM;
+    }
+
+
+    if (value) {
+	// set attribute value
+	xml->attr[l + 1] = (char *)value; 
+    } else { 
+	// remove attribute
+        
+	if (xml->attr[c + 1][l / 2] & V3_XML_NAMEM) {
+	    V3_Free(xml->attr[l]);
 	}
 
-	V3_Free(root->ent); // free list of general entities
+        memmove(xml->attr + l, xml->attr + l + 2, (c - l + 2) * sizeof(char*));
+
+        xml->attr = tmp_realloc(xml->attr, c * sizeof(char *), (c + 2) * sizeof(char *));
+
+	// fix list of which name/vals are malloced
+        memmove(xml->attr[c + 1] + (l / 2), xml->attr[c + 1] + (l / 2) + 1,
+                (c / 2) - (l / 2)); 
+    }
+
+    // clear strdup() flag
+    xml->flags &= ~V3_XML_DUP; 
+
+    return xml;
+}
+
+// removes a tag along with its subtags without freeing its memory
+struct v3_xml * v3_xml_cut(struct v3_xml * xml) {
+    struct v3_xml * cur;
+
+    if (! xml) {
+	// nothing to do
+	return NULL; 
+    }
+
+    if (xml->next) {
+	// patch sibling list
+	xml->next->sibling = xml->sibling; 
+    }
+
+
+    if (xml->parent) { 
+	// not root tag
+
+	// find head of subtag list
+        cur = xml->parent->child; 
+
+        if (cur == xml) {
+	    // first subtag
+	    xml->parent->child = xml->ordered; 
+	} else { 
+	// not first subtag
+
+            while (cur->ordered != xml) {
+		cur = cur->ordered;
+	    }
+
+	    // patch ordered list
+            cur->ordered = cur->ordered->ordered; 
 
-        for (i = 0; (a = root->attr[i]); i++) {
-            for (j = 1; a[j++]; j += 2) {
-		// free malloced attribute values
-                if (a[j] && (a[j] < root->tmp_start || a[j] > root->tmp_end)) {
-		    V3_Free(a[j]);
+	    // go back to head of subtag list
+            cur = xml->parent->child; 
+
+            if (strcmp(cur->name, xml->name)) {
+		// not in first sibling list
+
+                while (strcmp(cur->sibling->name, xml->name)) {
+                    cur = cur->sibling;
+		}
+
+                if (cur->sibling == xml) { 
+		    // first of a sibling list
+                    cur->sibling = (xml->next) ? xml->next
+                                               : cur->sibling->sibling;
+                } else {
+		    // not first of a sibling list
+		    cur = cur->sibling;
 		}
+            }
+
+            while (cur->next && cur->next != xml) {
+		cur = cur->next;
 	    }
-            V3_Free(a);
-        }
 
-        if (root->attr[0]) {
-	    // free default attribute list
-	    V3_Free(root->attr);
+            if (cur->next) {
+		// patch next list
+		cur->next = cur->next->next; 
+	    }
+        } 
+   }
+    xml->ordered = xml->sibling = xml->next = NULL;
+    return xml;
+}
+
+
+
+
+/* ************************** */
+/* *** XML ENCODING       *** */
+/* ************************** */
+
+// Encodes ampersand sequences appending the results to *dst, reallocating *dst
+// if length excedes max. a is non-zero for attribute encoding. Returns *dst
+static char *ampencode(const char *s, size_t len, char **dst, size_t *dlen,
+                      size_t * max, short a)
+{
+    const char * e;
+    
+    for (e = s + len; s != e; s++) {
+        while (*dlen + 10 > *max) {
+	    *dst = tmp_realloc(*dst, *max, *max + V3_XML_BUFSIZE);
+	    *max += V3_XML_BUFSIZE;
 	}
 
-	V3_Free(root->str_ptr); // malloced xml data
+        switch (*s) {
+        case '\0': return *dst;
+        case '&': *dlen += sprintf(*dst + *dlen, "&amp;"); break;
+        case '<': *dlen += sprintf(*dst + *dlen, "&lt;"); break;
+        case '>': *dlen += sprintf(*dst + *dlen, "&gt;"); break;
+        case '"': *dlen += sprintf(*dst + *dlen, (a) ? "&quot;" : "\""); break;
+        case '\n': *dlen += sprintf(*dst + *dlen, (a) ? "&#xA;" : "\n"); break;
+        case '\t': *dlen += sprintf(*dst + *dlen, (a) ? "&#x9;" : "\t"); break;
+        case '\r': *dlen += sprintf(*dst + *dlen, "&#xD;"); break;
+        default: (*dst)[(*dlen)++] = *s;
+        }
     }
+    return *dst;
+}
 
-    v3_xml_free_attr(xml->attr); // tag attributes
 
-    if ((xml->flags & V3_XML_TXTM)) {
-	// character content
-	V3_Free(xml->txt); 
+
+// Recursively converts each tag to xml appending it to *s. Reallocates *s if
+// its length excedes max. start is the location of the previous tag in the
+// parent tag's character content. Returns *s.
+static char *toxml_r(struct v3_xml * xml, char **s, size_t *len, size_t *max,
+                    size_t start) {
+    int i;
+    char *txt = (xml->parent) ? xml->parent->txt : "";
+    size_t off = 0;
+
+    // parent character content up to this tag
+    *s = ampencode(txt + start, xml->off - start, s, len, max, 0);
+
+    while (*len + strlen(xml->name) + 4 > *max) {
+	// reallocate s
+        *s = tmp_realloc(*s, *max, *max + V3_XML_BUFSIZE);
+	*max += V3_XML_BUFSIZE;
     }
 
-    if ((xml->flags & V3_XML_NAMEM)) {
-	// tag name
-	V3_Free(xml->name);
+
+    *len += sprintf(*s + *len, "<%s", xml->name); // open tag
+    for (i = 0; xml->attr[i]; i += 2) { // tag attributes
+        if (v3_xml_attr(xml, xml->attr[i]) != xml->attr[i + 1]) continue;
+        while (*len + strlen(xml->attr[i]) + 7 > *max) {
+	    // reallocate s
+            *s = tmp_realloc(*s, *max, *max + V3_XML_BUFSIZE);
+	    *max += V3_XML_BUFSIZE;
+	}
+
+        *len += sprintf(*s + *len, " %s=\"", xml->attr[i]);
+        ampencode(xml->attr[i + 1], -1, s, len, max, 1);
+        *len += sprintf(*s + *len, "\"");
     }
 
-    V3_Free(xml);
+  
+    *len += sprintf(*s + *len, ">");
+
+    *s = (xml->child) ? toxml_r(xml->child, s, len, max, 0) //child
+                      : ampencode(xml->txt, -1, s, len, max, 0);  //data
+    
+    while (*len + strlen(xml->name) + 4 > *max) {
+	// reallocate s
+        *s = tmp_realloc(*s, *max, *max + V3_XML_BUFSIZE);
+	*max += V3_XML_BUFSIZE;
+    }
+
+    *len += sprintf(*s + *len, "</%s>", xml->name); // close tag
+
+    while (off < xml->off && txt[off]) off++; // make sure off is within bounds
+    return (xml->ordered) ? toxml_r(xml->ordered, s, len, max, off)
+                          : ampencode(txt + off, -1, s, len, max, 0);
 }
 
+// Converts an xml structure back to xml. Returns a string of xml data that
+// must be freed.
+char * v3_xml_tostr(struct v3_xml * xml) {
+    struct v3_xml * p = (xml) ? xml->parent : NULL;
+    struct v3_xml * o = (xml) ? xml->ordered : NULL;
+    struct v3_xml_root * root = (struct v3_xml_root *)xml;
+    size_t len = 0, max = V3_XML_BUFSIZE;
+    char *s = V3_Malloc(max);
+
+    if (!s) {
+	PrintError(VM_NONE, VCORE_NONE, "Cannot allocate in xml tostrr\n");
+	return NULL;
+    }
+
+    strcpy(s, "");
+
+    if (! xml || ! xml->name) return tmp_realloc(s, max, len + 1);
+    while (root->xml.parent) root = (struct v3_xml_root *)root->xml.parent; // root tag
+
+
+    xml->parent = xml->ordered = NULL;
+    s = toxml_r(xml, &s, &len, &max, 0);
+    xml->parent = p;
+    xml->ordered = o;
+
+
+    return tmp_realloc(s, max, len + 1);
+}