clang compiler warnings: Fix autological comparisons

This fixes autological comparison warnings in the following:
 * chan_skinny: letohl may return a signed or unsigned value, depending on the
   macro chosen
 * func_curl: Provide a specific cast to CURLoption to prevent mismatch
 * cel: Fix enum comparisons where the enum can never be negative
 * enum: Fix comparison of return result of dn_expand, which returns a signed
   int value
 * event: Fix enum comparisons where the enum can never be negative
 * indications: tone_data.freq1 and freq2 are unsigned, and hence can never be
   negative
 * presencestate: Use the actual enum value for INVALID state
 * security_events: Fix enum comparisons where the enum can never be negative
 * udptl: Don't bother to check if the return value from encode_length is less
   than 0, as it returns an unsigned int
 * translate: Since the parameters are unsigned int, don't bother checking
   to see if they are negative. The cast to unsigned int would already blow
   past the matrix bounds.

Review: https://reviewboard.asterisk.org/r/4533
ASTERISK-24917
Reported by: dkdegroot
patches:
  rb4533.patch submitted by dkdegroot (License 6600)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@434469 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_skinny.c

@@ -2229,6 +2229,7 @@ static char *callstate2str(int ind)
 static int transmit_response_bysession(struct skinnysession *s, struct skinny_req *req)
 {
 	int res = 0;
+	unsigned long len;
 
 	if (!s) {
 		ast_log(LOG_WARNING, "Asked to transmit to a non-existent session!\n");
@@ -2237,7 +2238,13 @@ static int transmit_response_bysession(struct skinnysession *s, struct skinny_re
 
 	ast_mutex_lock(&s->lock);
 
-	if ((letohl(req->len) > SKINNY_MAX_PACKET) || (letohl(req->len) < 0)) {
+	/* Don't optimize out assigning letohl() to len. It is necessary to guarantee that
+	 * the comparison will always catch invalid values.
+         * letohl() may or may not return a signed value depending upon which definition
+	 * is used.
+	 */
+	len = letohl(req->len);
+	if (SKINNY_MAX_PACKET < len) {
 		ast_log(LOG_WARNING, "transmit_response: the length of the request (%d) is out of bounds (%d)\n", letohl(req->len), SKINNY_MAX_PACKET);
 		ast_mutex_unlock(&s->lock);
 		return -1;

funcs/func_curl.c

@@ -171,7 +171,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #define CURLVERSION_ATLEAST(a,b,c) \
 	((LIBCURL_VERSION_MAJOR > (a)) || ((LIBCURL_VERSION_MAJOR == (a)) && (LIBCURL_VERSION_MINOR > (b))) || ((LIBCURL_VERSION_MAJOR == (a)) && (LIBCURL_VERSION_MINOR == (b)) && (LIBCURL_VERSION_PATCH >= (c))))
 
-#define CURLOPT_SPECIAL_HASHCOMPAT -500
+#define CURLOPT_SPECIAL_HASHCOMPAT ((CURLoption) -500)
 
 static void curlds_free(void *data);
 

include/asterisk/cel.h

@@ -53,6 +53,8 @@ enum ast_cel_ama_flag {
  * \brief CEL event types
  */
 enum ast_cel_event_type {
+	AST_CEL_INVALID_VALUE = -1,
+	AST_CEL_ALL = 0,
 	/*! \brief channel birth */
 	AST_CEL_CHANNEL_START = 1,
 	/*! \brief channel end */
@@ -105,7 +107,7 @@ enum ast_cel_event_type {
 	AST_CEL_FORWARD = 25,
 };
 
-/*! 
+/*!
  * \brief Check to see if CEL is enabled
  *
  * \since 1.8

main/cel.c

@@ -123,7 +123,7 @@ static char cel_dateformat[256];
  * \brief Map of ast_cel_event_type to strings
  */
 static const char * const cel_event_types[CEL_MAX_EVENT_IDS] = {
-	[0]                        = "ALL",
+	[AST_CEL_ALL]              = "ALL",
 	[AST_CEL_CHANNEL_START]    = "CHAN_START",
 	[AST_CEL_CHANNEL_END]      = "CHAN_END",
 	[AST_CEL_ANSWER]           = "ANSWER",
@@ -256,15 +256,12 @@ enum ast_cel_event_type ast_cel_str_to_event_type(const char *name)
 	unsigned int i;
 
 	for (i = 0; i < ARRAY_LEN(cel_event_types); i++) {
-		if (!cel_event_types[i]) {
-			continue;
-		}
-
-		if (!strcasecmp(name, cel_event_types[i])) {
+		if (cel_event_types[i] && !strcasecmp(name, cel_event_types[i])) {
 			return i;
 		}
 	}
 
+	ast_log(LOG_ERROR, "Unknown event name '%s'\n", name);
 	return -1;
 }
 
@@ -288,10 +285,10 @@ static void parse_events(const char *val)
 
 		event_type = ast_cel_str_to_event_type(cur_event);
 
-		if (event_type == 0) {
+		if (event_type == AST_CEL_ALL) {
 			/* All events */
 			eventset = (int64_t) -1;
-		} else if (event_type == -1) {
+		} else if (event_type == AST_CEL_INVALID_VALUE) {
 			ast_log(LOG_WARNING, "Unknown event name '%s'\n",
 					cur_event);
 		} else {
@@ -416,7 +413,7 @@ const char *ast_cel_get_type_name(enum ast_cel_event_type type)
 
 const char *ast_cel_get_ama_flag_name(enum ast_cel_ama_flag flag)
 {
-	if (flag < 0 || flag >= ARRAY_LEN(cel_ama_flags)) {
+	if (flag >= ARRAY_LEN(cel_ama_flags)) {
 		ast_log(LOG_WARNING, "Invalid AMA flag: %u\n", flag);
 		return "Unknown";
 	}

main/enum.c

@@ -250,7 +250,7 @@ struct ebl_context {
 static int ebl_callback(void *context, unsigned char *answer, int len, unsigned char *fullanswer)
 {
 	struct ebl_context *c = context;
-	unsigned int i;
+	int i;
 
 	c->pos = 0;	/* default to empty */
 	c->separator[0] = 0;

main/event.c

@@ -295,7 +295,7 @@ const char *ast_event_get_type_name(const struct ast_event *event)
 
 	type = ast_event_get_type(event);
 
-	if (type < 0 || type >= ARRAY_LEN(event_names)) {
+	if (type >= ARRAY_LEN(event_names)) {
 		ast_log(LOG_ERROR, "Invalid event type - '%u'\n", type);
 		return "";
 	}
@@ -725,6 +725,7 @@ void ast_event_report_subs(const struct ast_event_sub *event_sub)
 	struct ast_event *event;
 	struct ast_event_sub *sub;
 	enum ast_event_type event_type = -1;
+	int found = 0;
 	struct ast_event_ie_val *ie_val;
 
 	if (event_sub->type != AST_EVENT_SUB)
@@ -733,12 +734,14 @@ void ast_event_report_subs(const struct ast_event_sub *event_sub)
 	AST_LIST_TRAVERSE(&event_sub->ie_vals, ie_val, entry) {
 		if (ie_val->ie_type == AST_EVENT_IE_EVENTTYPE) {
 			event_type = ie_val->payload.uint;
+			found = 1;
 			break;
 		}
 	}
 
-	if (event_type == -1)
+	if (!found) {
 		return;
+	}
 
 	AST_RWDLLIST_RDLOCK(&ast_event_subs[event_type]);
 	AST_RWDLLIST_TRAVERSE(&ast_event_subs[event_type], sub, entry) {
@@ -763,7 +766,7 @@ struct ast_event_sub *ast_event_subscribe_new(enum ast_event_type type,
 {
 	struct ast_event_sub *sub;
 
-	if (type < 0 || type >= AST_EVENT_TOTAL) {
+	if (type >= AST_EVENT_TOTAL) {
 		ast_log(LOG_ERROR, "%u is an invalid type!\n", type);
 		return NULL;
 	}

main/indications.c

@@ -360,14 +360,13 @@ int ast_playtones_start(struct ast_channel *chan, int vol, const char *playlst,
 
 		if (tone_data.midinote) {
 			/* midi notes must be between 0 and 127 */
-
-			if (tone_data.freq1 >= 0 && tone_data.freq1 <= 127) {
+			if (tone_data.freq1 <= 127) {
 				tone_data.freq1 = midi_tohz[tone_data.freq1];
 			} else {
 				tone_data.freq1 = 0;
 			}
 
-			if (tone_data.freq2 >= 0 && tone_data.freq2 <= 127) {
+			if (tone_data.freq2 <= 127) {
 				tone_data.freq2 = midi_tohz[tone_data.freq2];
 			} else {
 				tone_data.freq2 = 0;

main/presencestate.c

@@ -240,7 +240,7 @@ static void do_presence_state_change(const char *provider)
 
 	state = ast_presence_state_helper(provider, &subtype, &message, 0);
 
-	if (state < 0) {
+	if (state == AST_PRESENCE_INVALID) {
 		return;
 	}
 

main/security_events.c

@@ -427,7 +427,7 @@ const char *ast_security_event_severity_get_name(
 
 static int check_event_type(const enum ast_security_event_type event_type)
 {
-	if (event_type < 0 || event_type >= AST_SECURITY_EVENT_NUM_TYPES) {
+	if (event_type >= AST_SECURITY_EVENT_NUM_TYPES) {
 		ast_log(LOG_ERROR, "Invalid security event type %u\n", event_type);
 		return -1;
 	}
@@ -680,7 +680,7 @@ int ast_security_event_report(const struct ast_security_event_common *sec)
 {
 	int res;
 
-	if (sec->event_type < 0 || sec->event_type >= AST_SECURITY_EVENT_NUM_TYPES) {
+	if (sec->event_type >= AST_SECURITY_EVENT_NUM_TYPES) {
 		ast_log(LOG_ERROR, "Invalid security event type\n");
 		return -1;
 	}

main/translate.c

@@ -263,9 +263,6 @@ static void matrix_clear(void)
  */
 static struct translator_path *matrix_get(unsigned int x, unsigned int y)
 {
-	if (!(x >= 0 && y >= 0)) {
-		return NULL;
-	}
 	return __matrix[x] + y;
 }
 

main/udptl.c

@@ -320,8 +320,7 @@ static int encode_open_type(const struct ast_udptl *udptl, uint8_t *buf, unsigne
 	}
 	/* Encode the open type */
 	for (octet_idx = 0; ; num_octets -= enclen, octet_idx += enclen) {
-		if ((enclen = encode_length(buf, len, num_octets)) < 0)
-			return -1;
+		enclen = encode_length(buf, len, num_octets);
 		if (enclen + *len > buflen) {
 			ast_log(LOG_ERROR, "UDPTL (%s): Buffer overflow detected (%u + %u > %u)\n",
 				LOG_TAG(udptl), enclen, *len, buflen);
@@ -604,8 +603,7 @@ static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, unsigned int bu
 		buf[len++] = 0x00;
 		/* The number of entries will always be zero, so it is pointless allowing
 		   for the fragmented case here. */
-		if (encode_length(buf, &len, 0) < 0)
-			return -1;
+		encode_length(buf, &len, 0);
 		break;
 	case UDPTL_ERROR_CORRECTION_REDUNDANCY:
 		/* Encode the error recovery type */
@@ -616,8 +614,7 @@ static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, unsigned int bu
 			entries = s->tx_seq_no;
 		/* The number of entries will always be small, so it is pointless allowing
 		   for the fragmented case here. */
-		if (encode_length(buf, &len, entries) < 0)
-			return -1;
+		encode_length(buf, &len, entries);
 		/* Encode the elements */
 		for (i = 0; i < entries; i++) {
 			j = (entry - i - 1) & UDPTL_BUF_MASK;