Convert packet parsing

1 files changed, 118 insertions, 196 deletions

diff --git a/qarsh_packet.c b/qarsh_packet.c
index fea4435..dfd6e72 100644
--- a/qarsh_packet.c
+++ b/qarsh_packet.c
@@ -30,6 +30,7 @@
 #include <string.h>
 #include <assert.h>
 #include <sys/wait.h>
+#include <stdint.h>
 #include <endian.h>
 
 #include <libxml/parser.h>
@@ -38,18 +39,16 @@
 #include "qarsh_packet.h"
 
 /* Prototypes */
-static char *get_xpath_string(xmlXPathContextPtr ctxt, const char *xpath_query);
-
-int parse_qp_hello(xmlXPathContextPtr ctxt, struct qa_packet *qp);
-int parse_qp_returncode(xmlXPathContextPtr ctxt, struct qa_packet *qp);
-int parse_qp_ack(xmlXPathContextPtr ctxt, struct qa_packet *qp);
-int parse_qp_runcmd(xmlXPathContextPtr ctxt, struct qa_packet *qp);
-int parse_qp_cmdexit(xmlXPathContextPtr ctxt, struct qa_packet *qp);
-int parse_qp_setuser(xmlXPathContextPtr ctxt, struct qa_packet *qp);
-int parse_qp_kill(xmlXPathContextPtr ctxt, struct qa_packet *qp);
-int parse_qp_recvfile(xmlXPathContextPtr ctxt, struct qa_packet *qp);
-int parse_qp_sendfile(xmlXPathContextPtr ctxt, struct qa_packet *qp);
-int parse_qp_rstat(xmlXPathContextPtr ctxt, struct qa_packet *qp);
+void parse_qp_hello(char *buf, int *buflen, struct qa_packet *qp);
+void parse_qp_returncode(char *buf, int *buflen, struct qa_packet *qp);
+void parse_qp_ack(char *buf, int *buflen, struct qa_packet *qp);
+void parse_qp_runcmd(char *buf, int *buflen, struct qa_packet *qp);
+void parse_qp_cmdexit(char *buf, int *buflen, struct qa_packet *qp);
+void parse_qp_setuser(char *buf, int *buflen, struct qa_packet *qp);
+void parse_qp_kill(char *buf, int *buflen, struct qa_packet *qp);
+void parse_qp_recvfile(char *buf, int *buflen, struct qa_packet *qp);
+void parse_qp_sendfile(char *buf, int *buflen, struct qa_packet *qp);
+void parse_qp_rstat(char *buf, int *buflen, struct qa_packet *qp);
 
 char *store_qp_hello(char *buf, struct qa_packet *qp);
 char *store_qp_returncode(char *buf, struct qa_packet *qp);
@@ -83,7 +82,7 @@ void dump_qp_rstat(struct qa_packet *qp);
 
 struct packet_internals {
 	char *pi_name;
-	int (*pi_parse)(xmlXPathContextPtr ctxt, struct qa_packet *qp);
+	void (*pi_parse)(char *buf, int *buflen, struct qa_packet *qp);
 	char *(*pi_store)(char *buf, struct qa_packet *qp);
 	void (*pi_free)(struct qa_packet *qp);
 	void (*pi_dump)(struct qa_packet *qp);
@@ -191,237 +190,160 @@ qp_packet_type(enum qa_packet_type t)
 /*
  * Packet parsing functions
  */
-int
-parse_qp_hello(xmlXPathContextPtr ctxt, struct qa_packet *qp)
+
+char *
+fetch_int(char *buf, int *buflen, int *out)
 {
-	qp->qp_hello.qp_greeting = get_xpath_string(ctxt,
-			"param[@name='greeting']");
-	return 0;
+	int i;
+	if (*buflen < sizeof i) {
+		printf("Not enough data to unpack a uint32_t, %d\n", *buflen);
+		return buf;
+	}
+	memcpy(&i, buf, sizeof i);
+	*out = be32toh(i);
+	*buflen -= sizeof i;
+	return buf + sizeof i;
 }
 
-int
-parse_qp_returncode(xmlXPathContextPtr ctxt, struct qa_packet *qp)
+char *
+fetch_string(char *buf, int *buflen, char **out)
 {
-	char *s;
-	s = get_xpath_string(ctxt, "param[@name='rc']");
-	qp->qp_returncode.qp_rc = atoi(s);
-	free(s);
-	s = get_xpath_string(ctxt, "param[@name='errno']");
-	qp->qp_returncode.qp_errno = atoi(s);
-	free(s);
-	qp->qp_returncode.qp_strerror = get_xpath_string(ctxt,
-			"param[@name='strerror']");
-	return 0;
-}
+	int slen;
+	if (*buflen < sizeof slen) {
+		printf("Not enough data to unpack string length, %d\n", *buflen);
+		*out = NULL;
+		return buf;
+	}
+	buf = fetch_int(buf, buflen, &slen);
+	if (slen > *buflen) {
+		printf("String is more than available data, %d > %d\n", slen, *buflen);
+		*out = NULL;
+		return buf;
+	}
+	*out = malloc(slen+1);
+	memcpy(*out, buf, slen);
+	(*out)[slen] = '\0';
 
-int
-parse_qp_runcmd(xmlXPathContextPtr ctxt, struct qa_packet *qp)
-{
-	char *s;
-	qp->qp_runcmd.qp_cmdline = get_xpath_string(ctxt,
-			"param[@name='cmdline']");
-	s = get_xpath_string(ctxt, "param[@name='stdin']");
-	qp->qp_runcmd.qp_stdin_port = atoi(s);
-	free(s);
-	s = get_xpath_string(ctxt, "param[@name='stdout']");
-	qp->qp_runcmd.qp_stdout_port = atoi(s);
-	free(s);
-	s = get_xpath_string(ctxt, "param[@name='stderr']");
-	qp->qp_runcmd.qp_stderr_port = atoi(s);
-	free(s);
-	return 0;
+	*buflen -= slen;
+	return buf+slen;
 }
 
-int
-parse_qp_ack(xmlXPathContextPtr ctxt, struct qa_packet *qp)
+char *
+fetch_off_t(char *buf, int *buflen, off_t *out)
 {
-	char *s;
-	s = get_xpath_string(ctxt, "param[@name='type']");
-	qp->qp_ack.qp_ack_type = parse_packet_type(s);
-	free(s);
-	s = get_xpath_string(ctxt, "param[@name='seq']");
-	qp->qp_ack.qp_ack_seq = atoi(s);
-	free(s);
-	return 0;
+	off_t i;
+	if (*buflen < sizeof i) {
+		printf("Not enough data to unpack a off_t, %d\n", *buflen);
+		return buf;
+	}
+	memcpy(&i, buf, sizeof i);
+	*out = be64toh(i);
+	*buflen -= sizeof i;
+	return buf + sizeof i;
 }
 
-int
-parse_qp_cmdexit(xmlXPathContextPtr ctxt, struct qa_packet *qp)
+void
+parse_qp_hello(char *buf, int *buflen, struct qa_packet *qp)
 {
-	char *s;
-
-	s = get_xpath_string(ctxt, "param[@name='status']");
-	qp->qp_cmdexit.qp_status = atoi(s);
-	free(s);
-	return 0;
+	fetch_string(buf, buflen, &(qp->qp_hello.qp_greeting));
 }
 
-int
-parse_qp_setuser(xmlXPathContextPtr ctxt, struct qa_packet *qp)
+void
+parse_qp_returncode(char *buf, int *buflen, struct qa_packet *qp)
 {
-	qp->qp_setuser.qp_user = get_xpath_string(ctxt, "param[@name='user']");
-	qp->qp_setuser.qp_group = get_xpath_string(ctxt, "param[@name='group']");
-	return 0;
+	buf = fetch_int(buf, buflen, &(qp->qp_returncode.qp_rc));
+	buf = fetch_int(buf, buflen, &(qp->qp_returncode.qp_errno));
+	buf = fetch_string(buf, buflen, &(qp->qp_returncode.qp_strerror));
 }
-	
-int
-parse_qp_kill(xmlXPathContextPtr ctxt, struct qa_packet *qp)
-{
-	char *s;
 
-	s = get_xpath_string(ctxt, "param[@name='signal']");
-	qp->qp_kill.qp_sig = atoi(s);
-	free(s);
-	return 0;
+void
+parse_qp_runcmd(char *buf, int *buflen, struct qa_packet *qp)
+{
+	buf = fetch_string(buf, buflen, &(qp->qp_runcmd.qp_cmdline));
+	buf = fetch_int(buf, buflen, &(qp->qp_runcmd.qp_stdin_port));
+	buf = fetch_int(buf, buflen, &(qp->qp_runcmd.qp_stdout_port));
+	buf = fetch_int(buf, buflen, &(qp->qp_runcmd.qp_stderr_port));
 }
 
-int
-parse_qp_recvfile(xmlXPathContextPtr ctxt, struct qa_packet *qp)
+void
+parse_qp_ack(char *buf, int *buflen, struct qa_packet *qp)
 {
-	char *s;
-
-	qp->qp_recvfile.qp_path = get_xpath_string(ctxt, "param[@name='path']");
-
-	s = get_xpath_string(ctxt, "param[@name='if_port']");
-	qp->qp_recvfile.qp_if_port = atoi(s);
-	free(s);
-
-	s = get_xpath_string(ctxt, "param[@name='count']");
-	qp->qp_recvfile.qp_count = atoll(s);
-	free(s);
-
-	s = get_xpath_string(ctxt, "param[@name='mode']");
-	qp->qp_recvfile.qp_mode = atoi(s);
-	free(s);
-
-	return 0;
+	buf = fetch_int(buf, buflen, &(qp->qp_ack.qp_ack_type));
+	buf = fetch_int(buf, buflen, &(qp->qp_ack.qp_ack_seq));
 }
 
-int
-parse_qp_sendfile(xmlXPathContextPtr ctxt, struct qa_packet *qp)
+void
+parse_qp_cmdexit(char *buf, int *buflen, struct qa_packet *qp)
 {
-	char *s;
-
-	qp->qp_sendfile.qp_path = get_xpath_string(ctxt, "param[@name='path']");
-	s = get_xpath_string(ctxt, "param[@name='of_port']");
-	qp->qp_sendfile.qp_of_port = atoi(s);
-	free(s);
-	return 0;
+	buf = fetch_int(buf, buflen, &(qp->qp_cmdexit.qp_pid));
+	buf = fetch_int(buf, buflen, &(qp->qp_cmdexit.qp_status));
 }
 
-int
-parse_qp_rstat(xmlXPathContextPtr ctxt, struct qa_packet *qp)
+void
+parse_qp_setuser(char *buf, int *buflen, struct qa_packet *qp)
 {
-	char *s;
-
-	qp->qp_rstat.qp_path = get_xpath_string(ctxt, "param[@name='path']");
-
-	s = get_xpath_string(ctxt, "param[@name='st_mode']");
-	qp->qp_rstat.qp_st_mode = atoi(s);
-	free(s);
+	buf = fetch_string(buf, buflen, &(qp->qp_setuser.qp_user));
+       	if (*buflen)
+		buf = fetch_string(buf, buflen, &(qp->qp_setuser.qp_group));
+}
+	
+void
+parse_qp_kill(char *buf, int *buflen, struct qa_packet *qp)
+{
+	fetch_int(buf, buflen, &(qp->qp_kill.qp_sig));
+}
 
-	s = get_xpath_string(ctxt, "param[@name='st_uid']");
-	qp->qp_rstat.qp_st_uid = atoi(s);
-	free(s);
+void
+parse_qp_recvfile(char *buf, int *buflen, struct qa_packet *qp)
+{
+	buf = fetch_string(buf, buflen, &(qp->qp_recvfile.qp_path));
+	buf = fetch_int(buf, buflen, &(qp->qp_recvfile.qp_if_port));
+	buf = fetch_off_t(buf, buflen, &(qp->qp_recvfile.qp_count));
+	buf = fetch_int(buf, buflen, &(qp->qp_recvfile.qp_mode));
+}
 
-	s = get_xpath_string(ctxt, "param[@name='st_gid']");
-	qp->qp_rstat.qp_st_gid = atoi(s);
-	free(s);
+void
+parse_qp_sendfile(char *buf, int *buflen, struct qa_packet *qp)
+{
+	buf = fetch_string(buf, buflen, &(qp->qp_sendfile.qp_path));
+	buf = fetch_int(buf, buflen, &(qp->qp_sendfile.qp_of_port));
+}
 
-	s = get_xpath_string(ctxt, "param[@name='st_size']");
-	qp->qp_rstat.qp_st_size = atol(s);
-	free(s);
+void
+parse_qp_rstat(char *buf, int *buflen, struct qa_packet *qp)
+{
 
-	return 0;
+	buf = fetch_string(buf, buflen, &(qp->qp_rstat.qp_path));
+	buf = fetch_int(buf, buflen, &(qp->qp_rstat.qp_st_mode));
+	buf = fetch_int(buf, buflen, &(qp->qp_rstat.qp_st_uid));
+	buf = fetch_int(buf, buflen, &(qp->qp_rstat.qp_st_gid));
+	buf = fetch_off_t(buf, buflen, &(qp->qp_rstat.qp_st_size));
 }
 
 
 struct qa_packet *
-parse_packet(xmlXPathContextPtr ctxt)
+parse_packet(char *buf, int buflen)
 {
 	struct qa_packet *qp = NULL;
-	char *s;
 
 	qp = malloc(sizeof *qp);
 	assert(qp);
 	memset(qp, 0, sizeof *qp);
 
-	s = get_xpath_string(ctxt, "@type");
-	qp->qp_type = parse_packet_type(s);
-	free(s);
-	s = get_xpath_string(ctxt, "@seq");
-	qp->qp_seq = atoi(s);
-	free(s);
-	
+	buf = fetch_int(buf, &buflen, &(qp->qp_seq));
+	buf = fetch_int(buf, &buflen, &(qp->qp_type));
+
 	if (qa_pi[qp->qp_type].pi_parse)
-		qa_pi[qp->qp_type].pi_parse(ctxt, qp);
+		qa_pi[qp->qp_type].pi_parse(buf, &buflen, qp);
 	else {
-		printf("Packet type %s not implemented yet\n", s);
+		printf("Packet type %d not implemented yet\n", qp->qp_type);
 		free(qp);
 		qp = NULL;
 	}
+	if (buflen) { printf("%d remaining bytes of data in packet\n", buflen); }
 	return qp;
 }
 
-struct qa_packet *
-parse_packets(char *buf, int n)
-{
-	xmlDocPtr doc;
-	xmlXPathContextPtr context;
-	xmlXPathObjectPtr obj = NULL;
-	struct qa_packet *qp = NULL;
-	
-	doc = xmlParseMemory(buf, n);
-
-	/* If we can't parse the packet, we don't care about it */
-	if (doc == NULL) return NULL;
-
-	context = xmlXPathNewContext(doc);
-	obj = xmlXPathEvalExpression((xmlChar *)"//packet", context);
-	if (obj == NULL) {
-		printf("didn't find anything\n");
-		goto free_context;
-	} 
-	if (obj->type != XPATH_NODESET || obj->nodesetval->nodeNr == 0) {
-		printf("didn't find anything\n");
-		goto free_obj;
-	}
-	if (obj->nodesetval->nodeNr > 1) {
-		printf("One packet at a time please!\n");
-	}
-	context->node = xmlXPathNodeSetItem(obj->nodesetval, 0);
-	qp = parse_packet(context);
-
-free_obj:
-	xmlXPathFreeObject(obj);
-free_context:
-	xmlXPathFreeContext(context);
-	xmlFreeDoc(doc);
-	return qp;
-}
-
-
-static char *
-get_xpath_string(xmlXPathContextPtr ctxt, const char *xpath_query)
-{
-	xmlXPathObjectPtr obj = NULL;
-	char querystr[512];
-	char *ret;
-
-	snprintf(querystr, 512, "string(%s)", xpath_query);
-	obj = xmlXPathEvalExpression((xmlChar *)querystr, ctxt);
-
-	if (obj == NULL) return NULL;
-	if (obj->type != XPATH_STRING) { 
-		xmlXPathFreeObject(obj); 
-		return NULL;
-	}
-
-	ret = strdup((char *)obj->stringval);
-	xmlXPathFreeObject(obj);
-	return ret;
-}
-
 /*
  * Packet serialization functions
  *