Add no-caching feature

Signed-off-by: Jose Bollo <jose.bollo@iot.bzh>

9 files changed, 141 insertions, 41 deletions

diff --git a/src/anydb.c b/src/anydb.c
index bfd2c09..ef41af7 100644
--- a/src/anydb.c
+++ b/src/anydb.c
@@ -209,6 +209,8 @@ expired(
 	time_t expire,
 	time_t now
 ) {
+	if (expire < 0)
+		expire = -(expire + 1);
 	return expire && expire <= now;
 }
 
diff --git a/src/cache.c b/src/cache.c
index df346a8..d14e877 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -284,7 +284,7 @@ cache_put(
 	item_t *item;
 	size_t size;
 
-	if (cache == NULL || value < -128 || value > 127)
+	if (cache == NULL || value < -128 || value > 127 || expire < 0)
 		return -EINVAL;
 
 	item = search(cache, key);
diff --git a/src/cyn-server.c b/src/cyn-server.c
index 78143a4..8339d09 100644
--- a/src/cyn-server.c
+++ b/src/cyn-server.c
@@ -272,7 +272,7 @@ entercb(
 /** translate optional expire value */
 static
 const char *
-exp2txt(
+exp2check(
 	time_t expire,
 	char *buffer,
 	size_t bufsz
@@ -280,11 +280,37 @@ exp2txt(
 	if (!expire)
 		return NULL;
 
+	if (expire < 0)
+		return "-"; /* no cache */
+
 	/* TODO: check size */
 	snprintf(buffer, bufsz, "%lld", (long long)expire);
 	return buffer;
 }
 
+/** translate optional expire value */
+static
+const char *
+exp2get(
+	time_t expire,
+	char *buffer,
+	size_t bufsz
+) {
+	if (!expire)
+		return NULL;
+
+	if (expire < 0) {
+		expire = -(expire + 1);
+		if (!expire)
+			return "-";
+		*buffer++ = '-';
+		bufsz--;
+	}
+
+	snprintf(buffer, bufsz, "%lld", (long long)expire);
+	return buffer;
+}
+
 /** callback of checking */
 static
 void
@@ -299,7 +325,7 @@ testcheckcb(
 
 	if (!value) {
 		vtxt = _no_;
-		etxt = 0;
+		etxt = NULL;
 	} else {
 		if (!strcmp(value->value, ALLOW))
 			vtxt = _yes_;
@@ -307,7 +333,7 @@ testcheckcb(
 			vtxt = _no_;
 		else
 			vtxt = _done_;
-		etxt = exp2txt(value->expire, text, sizeof text);
+		etxt = exp2check(value->expire, text, sizeof text);
 	}
 	putx(cli, vtxt, etxt, NULL);
 	flushw(cli);
@@ -346,7 +372,7 @@ getcb(
 	char text[30];
 
 	putx(cli, _item_, key->client, key->session, key->user, key->permission,
-		value->value, exp2txt(value->expire, text, sizeof text), NULL);
+		value->value, exp2get(value->expire, text, sizeof text), NULL);
 }
 
 /** handle a request */
diff --git a/src/cynagora.c b/src/cynagora.c
index ee55dc6..4434d89 100644
--- a/src/cynagora.c
+++ b/src/cynagora.c
@@ -363,10 +363,12 @@ status_check(
 	else
 		rc = -EPROTO;
 
-	if (cynagora->reply.count >= 2)
-		*expire = strtoll(cynagora->reply.fields[1], NULL, 10);
-	else
+	if (cynagora->reply.count < 2)
 		*expire = 0;
+	else if (cynagora->reply.fields[1][0] == '-')
+		*expire = -1;
+	else
+		*expire = strtoll(cynagora->reply.fields[1], NULL, 10);
 
 	return rc;
 }
@@ -553,7 +555,7 @@ check_or_test(
 		rc = wait_pending_reply(cynagora);
 		if (rc >= 0) {
 			rc = status_check(cynagora, &expire);
-			if (rc >= 0 && action == _check_ && cynagora->cache)
+			if (rc >= 0 && action == _check_)
 				cache_put(cynagora->cache, key, rc, expire);
 		}
 	}
diff --git a/src/cynagora.h b/src/cynagora.h
index d17476c..b77c0f4 100644
--- a/src/cynagora.h
+++ b/src/cynagora.h
@@ -58,7 +58,7 @@ struct cynagora_key {
 struct cynagora_value {
 	/** the associated value */
 	const char *value;
-	/** the expiration */
+	/** the expiration in seconds since epoch, negative to avoid cache */
 	time_t expire;
 };
 
diff --git a/src/dbinit.c b/src/dbinit.c
index e2366ad..67738f4 100644
--- a/src/dbinit.c
+++ b/src/dbinit.c
@@ -96,8 +96,7 @@ int dbinit_add_file(const char *path)
 		key.user = item[2];
 		key.permission = item[3];
 		value.value = item[4];
-		value.expire = txt2exp(item[5]);
-		if (value.expire < 0) {
+		if (!txt2exp(item[5], &value.expire)) {
 			fprintf(stderr, "bad expiration %s (%s:%d)\n", item[5], path, lino);
 			rc = -EINVAL;
 			goto error2;
diff --git a/src/expire.c b/src/expire.c
index 23ce6ae..2207d3c 100644
--- a/src/expire.c
+++ b/src/expire.c
@@ -20,9 +20,11 @@
 /******************************************************************************/
 /******************************************************************************/
 
+#include <stdbool.h>
 #include <time.h>
 #include <string.h>
 #include <stdio.h>
+#include <limits.h>
 
 #include "expire.h"
 
@@ -31,52 +33,116 @@ static const int MIN = 60;
 static const int HOUR = 60*60;
 static const int DAY = 24*60*60;
 static const int WEEK = 7*24*60*60;
-static const int YEAR = 365*24*60*60 + 24*60*60/4;
+static const int YEAR = 365*24*60*60 + 24*60*60/4; /* average includes leap */
+static const time_t TMIN = (time_t)1 << ((CHAR_BIT * sizeof(time_t)) - 1);
+static const time_t TMAX = ~TMIN;
 
-/* see expire.h */
-time_t txt2exp(const char *txt)
+/** add positives x and y with saturation */
+static time_t pt_add(time_t x, time_t y)
 {
-	time_t r, x;
+	time_t r = x + y;
+	return r < 0 ? TMAX : r;
+}
 
-	/* infinite time */
-	if (!strcmp(txt, "always") || !strcmp(txt, "forever") || !strcmp(txt, "*"))
-		return 0;
+/** multiply positive x by m with saturation */
+static time_t pt_mul(time_t x, int m)
+{
+	time_t r;
+
+	if (m <= 1)
+		r = 0;
+	else {
+		r = pt_mul(x, m >> 1) << 1;
+		if (r < 0)
+			r = TMAX;
+	}
+	return (m & 1) ? pt_add(r, x) : r;
+}
+
+/** multiply positive x by m and then add y with saturation */
+static time_t pt_muladd(time_t x, int m, time_t y)
+{
+	return pt_add(pt_mul(x, m), y);
+}
+
+/** multiply positive x by 10 and then add d with saturation */
+static time_t pt_tm10a(time_t x, int d)
+{
+	return pt_muladd(x, 10, (time_t)d);
+}
+
+/** translate the string 'txt' to its time representation */
+static bool parse_time_spec(const char *txt, time_t *time_out)
+{
+	time_t r, x;
 
 	/* parse */
-	r = time(NULL);
+	r = 0;
 	while(*txt) {
 		x = 0;
 		while('0' <= *txt && *txt <= '9')
-			x = (x << 3) + (x << 1) + (time_t)(*txt++ - '0');
+			x = pt_tm10a(x, *txt++ - '0');
 		switch(*txt) {
-		case 'y': r += x * YEAR; txt++; break;
-		case 'w': r += x * WEEK; txt++; break;
-		case 'd': r += x * DAY; txt++; break;
-		case 'h': r += x * HOUR; txt++; break;
-		case 'm': r += x * MIN; txt++; break;
+		case 'y': r = pt_muladd(x, YEAR, r); txt++; break;
+		case 'w': r = pt_muladd(x, WEEK, r); txt++; break;
+		case 'd': r = pt_muladd(x, DAY, r); txt++; break;
+		case 'h': r = pt_muladd(x, HOUR, r); txt++; break;
+		case 'm': r = pt_muladd(x, MIN, r); txt++; break;
 		case 's': txt++; /*@fallthrough@*/
-		case 0: r += x * SEC; break;
-		default: return -1;
+		case 0: r = pt_muladd(x, SEC, r); break;
+		default: return false;
 		}
 	}
-	return r;
+	*time_out = r;
+	return true;
+}
+
+
+/* see expire.h */
+bool txt2exp(const char *txt, time_t *time_out)
+{
+	bool nocache;
+	time_t r;
+
+	/* no cache */
+	nocache = txt[0] == '-';
+	txt += nocache;
+
+	/* infinite time */
+	if (!txt[0] || !strcmp(txt, "always") || !strcmp(txt, "forever") || !strcmp(txt, "*")) {
+		r = 0;
+	} else {
+		/* parse */
+		if (!parse_time_spec(txt, &r))
+			return false;
+		/* relative time */
+		r = pt_add(r, time(NULL));
+	}
+
+	*time_out = nocache ? -(r + 1) : r;
+	return true;
 }
 
 /* see expire.h */
 size_t exp2txt(time_t expire, char *buffer, size_t buflen)
 {
 	char b[100];
-	size_t l;
-	int n;
+	size_t l, n;
 
-	if (!expire)
-		strncpy(b, "forever", sizeof b);
-	else {
+	n = 0;
+	if (expire < 0) {
+		b[n++] = '-';
+		b[n] = 0;
+		expire = -(expire + 1);
+	}
+	if (!expire) {
+		if (!n)
+			strncpy(b, "forever", sizeof b);
+	} else {
 		expire -= time(NULL);
-		n = 0;
 #define ADD(C,U) \
   if (expire >= U) { \
-    n += snprintf(&b[n], sizeof b - (size_t)n, "%lld" #C, (long long)(expire / U)); \
+    n += (size_t)snprintf(&b[n], sizeof b - (size_t)n, "%lld" #C, (long long)(expire / U)); \
     expire %= U; \
   }
 		ADD(y,YEAR)
diff --git a/src/expire.h b/src/expire.h
index 1de82c2..4d996f8 100644
--- a/src/expire.h
+++ b/src/expire.h
@@ -34,12 +34,14 @@
  *  - 2m2w means two months and 2 weeks
  *
  * @param txt the text to convert
- * @return the value for the text
+ * @param time_out where to store the result
+ * @return true if valid false otherwise
  */
 extern
-time_t
+bool
 txt2exp(
-	const char *txt
+	const char *txt,
+	time_t *time_out
 );
 
 /**
diff --git a/src/main-cynagoracli.c b/src/main-cynagoracli.c
index db36243..af84760 100644
--- a/src/main-cynagoracli.c
+++ b/src/main-cynagoracli.c
@@ -334,9 +334,12 @@ int get_csupve(int ac, char **av, int *used, const char *def)
 	key.user = n > 3 ? av[3] : def;
 	key.permission = n > 4 ? av[4] : def;
 	value.value = n > 5 ? av[5] : "no";
-	value.expire = n > 6 ? txt2exp(av[6]) : 0;
+	if (n <= 6)
+		value.expire = 0;
+	else if (!txt2exp(av[6], &value.expire))
+		return -EINVAL;
 
-	return key.client && key.session && key.user && key.permission && value.value && value.expire >= 0 ? 0 : -EINVAL;
+	return key.client && key.session && key.user && key.permission && value.value ? 0 : -EINVAL;
 }
 
 int get_csup(int ac, char **av, int *used, const char *def)