From 89de95a89953c20349a8c7c4684eba45feb34bf5 Mon Sep 17 00:00:00 2001
From: Jonathan McCrohan <jmccrohan@gmail.com>
Date: Mon, 5 Mar 2012 22:35:04 +0000
Subject: Imported Upstream version 0.7.4

---
 iw_if.c | 49 +++++++++++++++++++++++++++++--------------------
 1 file changed, 29 insertions(+), 20 deletions(-)

(limited to 'iw_if.c')

diff --git a/iw_if.c b/iw_if.c
index 708ff85..8a635f6 100644
--- a/iw_if.c
+++ b/iw_if.c
@@ -94,39 +94,45 @@ void if_getinf(const char *ifname, struct if_info *info)
 	close(skfd);
 }
 
-static FILE *open_proc_net(const char *filename)
-{
-	char path[128];
-	FILE *fp;
-
-	snprintf(path, sizeof(path), "/proc/net/%s", filename);
-	if (access(path, F_OK) != 0)
-		err_quit("'%s' not accessible - not compiled in?", path);
-
-	fp = fopen(path, "r");
-	if (fp == NULL)
-		err_sys("can not open %s", path);
-
-	return fp;
-}
-
 /**
  * iw_get_interface_list  -  Return NULL-terminated array of WiFi interfaces.
+ * Use the safe route of checking /proc/net/dev/ for wireless interfaces:
+ * - SIOCGIFCONF only returns running interfaces that have an IP address;
+ * - /proc/net/wireless may exist, but may not list all wireless interfaces.
  */
 char **iw_get_interface_list(void)
 {
 	char **if_list = NULL, *p, tmp[BUFSIZ];
 	int  nifs = 1;		/* if_list[nifs-1] = NULL */
-	FILE *fp = open_proc_net("wireless");
+	struct iwreq wrq;
+	FILE *fp;
+	int skfd = socket(AF_INET, SOCK_DGRAM, 0);
+
+	if (skfd < 0)
+		err_sys("%s: can not open socket", __func__);
+
+	fp = fopen("/proc/net/dev", "r");
+	if (fp == NULL)
+		err_sys("can not open /proc/net/dev");
 
-	while (fgets(tmp, sizeof(tmp), fp))
+	while (fgets(tmp, sizeof(tmp), fp)) {
 		if ((p = strchr(tmp, ':'))) {
-			if_list = realloc(if_list, sizeof(char *) * (nifs + 1));
 			for (*p = '\0', p = tmp; isspace(*p); )
 				p++;
+			/*
+			 * Use SIOCGIWNAME as indicator: if interface does not
+			 * support this ioctl, it has no wireless extensions.
+			 */
+			strncpy(wrq.ifr_name, p, IFNAMSIZ);
+			if (ioctl(skfd, SIOCGIWNAME, &wrq) < 0)
+				continue;
+
+			if_list = realloc(if_list, sizeof(char *) * (nifs + 1));
 			if_list[nifs-1] = strdup(p);
 			if_list[nifs++] = NULL;
 		}
+	}
+	close(skfd);
 	fclose(fp);
 	return if_list;
 }
@@ -136,8 +142,11 @@ void if_getstat(const char *ifname, struct if_stat *stat)
 	char line[0x100];
 	unsigned long d;
 	char *lp;
-	FILE *fp = open_proc_net("dev");
+	const char path[] = "/proc/net/dev";
+	FILE *fp = fopen(path, "r");
 
+	if (fp == NULL)
+		err_sys("can not open %s", path);
 	/*
 	 * Inter-|   Receive                                                | Transmit
 	 *  face |bytes    packets errs drop fifo frame compressed multicast|bytes packets
-- 
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