. DS understands publishing and subscribing where keys are in string

form. Subscriptions are regular expressions.
 . different types are stored per key; currently u32 and/or string.
   the same key can be referenced (publish, subscribe, check) as any type.
 . notify()s are sent when subscriptions are triggered (publishing or
   updating of matching keys); optionally, a subscribe flag sends
   updates for all matching keys at subscription time, instead of only
   after updates after subscribing
 . all interfacing to ds is in /usr/src/lib/syslib/ds.c.
 . subscribe is ds_subscribe
   publish functions are ds_publish_<type>
   retrieve functions are ds_retrieve_<type> (one-time retrieval of a value)
   check functions are ds_check_<type> (check for updated key caller
      subscribes to not yet checked for, or ESRCH for none)
 . ramdisk driver updated with new ds interface

lib/syslib/Makefile.in

@@ -63,6 +63,7 @@ libsys_FILES=" \
 	sys_voutb.c \
 	sys_voutl.c \
 	sys_voutw.c \
-	taskcall.c"
+	taskcall.c \
+	ds.c"
 
 TYPE=both

lib/syslib/ds.c

@@ -0,0 +1,259 @@
+
+#include <minix/ds.h>
+#include <string.h>
+
+#include "syslib.h"
+
+int
+ds_subscribe(ds_name_regexp, type, flags)
+char *ds_name_regexp;
+int type;
+int flags;
+{
+	int r;
+	message m;
+	cp_grant_id_t g;
+	size_t len;
+
+	len = strlen(ds_name_regexp)+1;
+	g = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) ds_name_regexp, len, CPF_READ);
+
+	if(!GRANT_VALID(g)) 
+		return -1;
+
+	flags &= DS_INITIAL;
+
+	m.DS_KEY_GRANT = (char *) g;
+	m.DS_KEY_LEN = len;
+	m.DS_FLAGS = flags | (type & DS_TYPE_MASK);
+
+	r = _taskcall(DS_PROC_NR, DS_SUBSCRIBE, &m);
+
+	cpf_revoke(g);
+
+	return r;
+}
+
+int ds_publish_u32(ds_name, value)
+char *ds_name;
+u32_t value;
+{
+	int r;
+	message m;
+	cp_grant_id_t g;
+	size_t len;
+
+	len = strlen(ds_name)+1;
+	g = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) ds_name, len, CPF_READ);
+
+	if(!GRANT_VALID(g)) 
+		return -1;
+
+	m.DS_KEY_GRANT = (char *) g;
+	m.DS_KEY_LEN = len;
+	m.DS_FLAGS = DS_TYPE_U32;
+	m.DS_VAL = value;
+	m.DS_VAL_LEN = sizeof(value);
+
+	r = _taskcall(DS_PROC_NR, DS_PUBLISH, &m);
+
+	cpf_revoke(g);
+
+	return r;
+}
+
+int ds_publish_str(ds_name, value)
+char *ds_name;
+char *value;
+{
+	int r;
+	message m;
+	cp_grant_id_t g_key, g_str;
+	size_t len_key, len_str;
+
+	/* Grant for key. */
+	len_key = strlen(ds_name)+1;
+	g_key = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) ds_name, len_key, CPF_READ);
+	if(!GRANT_VALID(g_key)) 
+		return -1;
+
+	/* Grant for value. */
+	len_str = strlen(value)+1;
+	g_str = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) value, len_str, CPF_READ);
+
+	if(!GRANT_VALID(g_str))  {
+		cpf_revoke(g_key);
+		return -1;
+	}
+
+	m.DS_KEY_GRANT = (char *) g_key;
+	m.DS_KEY_LEN = len_key;
+	m.DS_FLAGS = DS_TYPE_STR;
+	m.DS_VAL = g_str;
+	m.DS_VAL_LEN = len_str;
+
+	r = _taskcall(DS_PROC_NR, DS_PUBLISH, &m);
+
+	cpf_revoke(g_key);
+	cpf_revoke(g_str);
+
+	return r;
+}
+
+int ds_retrieve_u32(ds_name, value)
+char *ds_name;
+u32_t *value;
+{
+	int r;
+	message m;
+	cp_grant_id_t g_key;
+	size_t len_key;
+
+	/* Grant for key. */
+	len_key = strlen(ds_name)+1;
+	g_key = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) ds_name, len_key, CPF_READ);
+	if(!GRANT_VALID(g_key)) 
+		return -1;
+
+	/* Do request. */
+	m.DS_KEY_GRANT = (char *) g_key;
+	m.DS_KEY_LEN = len_key;
+	m.DS_FLAGS = DS_TYPE_U32;
+
+	r = _taskcall(DS_PROC_NR, DS_RETRIEVE, &m);
+
+	cpf_revoke(g_key);
+
+	/* Assign u32 value. */
+	*value = m.DS_VAL;
+
+	return r;
+}
+
+int ds_retrieve_str(ds_name, value, len_str)
+char *ds_name;
+char *value;
+size_t len_str;
+{
+	int r;
+	message m;
+	cp_grant_id_t g_key, g_str;
+	size_t len_key;
+
+	/* Grant for key. */
+	len_key = strlen(ds_name)+1;
+	g_key = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) ds_name, len_key, CPF_READ);
+	if(!GRANT_VALID(g_key)) 
+		return -1;
+
+	/* Grant for value. */
+	g_str = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) value, len_str, CPF_WRITE);
+
+	if(!GRANT_VALID(g_str))  {
+		cpf_revoke(g_key);
+		return -1;
+	}
+
+	/* Do request. */
+
+	m.DS_KEY_GRANT = (char *) g_key;
+	m.DS_KEY_LEN = len_key;
+	m.DS_FLAGS = DS_TYPE_STR;
+	m.DS_VAL = g_str;
+	m.DS_VAL_LEN = len_str;
+
+	r = _taskcall(DS_PROC_NR, DS_RETRIEVE, &m);
+
+	cpf_revoke(g_key);
+	cpf_revoke(g_str);
+
+	return r;
+}
+
+int ds_check_str(ds_key, len_key, value, len_str)
+char *ds_key;
+size_t len_key;
+char *value;
+size_t len_str;
+{
+	int r;
+	message m;
+	cp_grant_id_t g_key, g_str;
+
+	if(len_key < 1 || len_str < 1) return -1;
+
+	/* Grant for key. */
+	g_key = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) ds_key, len_key, CPF_WRITE);
+	if(!GRANT_VALID(g_key)) 
+		return -1;
+
+	/* Grant for value. */
+	g_str = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) value, len_str, CPF_WRITE);
+
+	if(!GRANT_VALID(g_str))  {
+		cpf_revoke(g_key);
+		return -1;
+	}
+
+	/* Do request. */
+
+	m.DS_KEY_GRANT = (char *) g_key;
+	m.DS_KEY_LEN = len_key;
+	m.DS_FLAGS = DS_TYPE_STR;
+	m.DS_VAL = g_str;
+	m.DS_VAL_LEN = len_str;
+
+	r = _taskcall(DS_PROC_NR, DS_CHECK, &m);
+
+	cpf_revoke(g_key);
+	cpf_revoke(g_str);
+
+	ds_key[len_key-1] = '\0';
+	value[len_str-1] = '\0';
+
+	return r;
+}
+
+int ds_check_u32(ds_key, len_key, value)
+char *ds_key;
+size_t len_key;
+u32_t *value;
+{
+	int r;
+	message m;
+	cp_grant_id_t g_key;
+
+	if(len_key < 1) return -1;
+
+	/* Grant for key. */
+	g_key = cpf_grant_direct(DS_PROC_NR,
+		(vir_bytes) ds_key, len_key, CPF_WRITE);
+	if(!GRANT_VALID(g_key)) 
+		return -1;
+
+	/* Do request. */
+	m.DS_KEY_GRANT = (char *) g_key;
+	m.DS_KEY_LEN = len_key;
+	m.DS_FLAGS = DS_TYPE_U32;
+
+	r = _taskcall(DS_PROC_NR, DS_CHECK, &m);
+
+	cpf_revoke(g_key);
+
+	ds_key[len_key-1] = '\0';
+
+	/* Assign u32 value. */
+	*value = m.DS_VAL;
+
+	return r;
+}
+

lib/syslib/safecopies.c

@@ -310,3 +310,4 @@ cp_grant_id_t gid;
 	return 0;
 }
 
+