Add support for the NO_PROXY / no_proxy environment variable as used by

lynx, curl etc.  Note that this patch differs significantly from that
in the PR, as the submitter refined it after submitting the PR.

PR:		110388
Submitted by:	Alexander Pohoyda <alexander.pohoyda@gmx.net>
MFC after:	3 weeks

4 files changed, 63 insertions, 8 deletions

diff --git a/lib/libfetch/common.c b/lib/libfetch/common.c
index dc9eee0..936524f 100644
--- a/lib/libfetch/common.c
+++ b/lib/libfetch/common.c
@@ -33,8 +33,10 @@ __FBSDID("$FreeBSD$");
 #include <sys/socket.h>
 #include <sys/time.h>
 #include <sys/uio.h>
+
 #include <netinet/in.h>
 
+#include <ctype.h>
 #include <errno.h>
 #include <netdb.h>
 #include <pwd.h>
@@ -734,3 +736,51 @@ fetch_netrc_auth(struct url *url)
 	fclose(f);
 	return (-1);
 }
+
+/*
+ * The no_proxy environment variable specifies a set of domains for
+ * which the proxy should not be consulted; the contents is a comma-,
+ * or space-separated list of domain names.  A single asterisk will
+ * override all proxy variables and no transactions will be proxied
+ * (for compatability with lynx and curl, see the discussion at
+ * <http://curl.haxx.se/mail/archive_pre_oct_99/0009.html>).
+ */
+int
+fetch_no_proxy_match(const char *host)
+{
+	const char *no_proxy, *p, *q;
+	size_t h_len, d_len;
+
+	if ((no_proxy = getenv("NO_PROXY")) == NULL &&
+	    (no_proxy = getenv("no_proxy")) == NULL)
+		return (0);
+
+	/* asterisk matches any hostname */
+	if (strcmp(no_proxy, "*") == 0)
+		return (1);
+
+	h_len = strlen(host);
+	p = no_proxy;
+	do {
+		/* position p at the beginning of a domain suffix */
+		while (*p == ',' || isspace((int)*p))
+			p++;
+
+		/* position q at the first separator character */
+		for (q = p; *q; ++q)
+			if (*q == ',' || isspace((int)*q))
+				break;
+
+		d_len = q - p;
+		if (d_len > 0 && h_len > d_len &&
+		    strncasecmp(host + h_len - d_len,
+			p, d_len) == 0) {
+			/* domain name matches */
+			return (1);
+		}
+
+		p = q + 1;
+	} while (*q);
+
+	return (0);
+}
diff --git a/lib/libfetch/common.h b/lib/libfetch/common.h
index 2382eb0..05bee03 100644
--- a/lib/libfetch/common.h
+++ b/lib/libfetch/common.h
@@ -90,6 +90,7 @@ int		 fetch_close(conn_t *);
 int		 fetch_add_entry(struct url_ent **, int *, int *,
 		     const char *, struct url_stat *);
 int		 fetch_netrc_auth(struct url *url);
+int		 fetch_no_proxy_match(const char *);
 
 #define ftp_seterr(n)	 fetch_seterr(ftp_errlist, n)
 #define http_seterr(n)	 fetch_seterr(http_errlist, n)
diff --git a/lib/libfetch/ftp.c b/lib/libfetch/ftp.c
index bac5c72..4316346e 100644
--- a/lib/libfetch/ftp.c
+++ b/lib/libfetch/ftp.c
@@ -1057,13 +1057,15 @@ ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
  * Check the proxy settings
  */
 static struct url *
-ftp_get_proxy(const char *flags)
+ftp_get_proxy(struct url * url, const char *flags)
 {
 	struct url *purl;
 	char *p;
 
 	if (flags != NULL && strchr(flags, 'd') != NULL)
 		return (NULL);
+	if (fetch_no_proxy_match(url->host))
+		return (NULL);
 	if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
 		(p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
 	    *p && (purl = fetchParseURL(p)) != NULL) {
@@ -1140,7 +1142,7 @@ ftp_request(struct url *url, const char *op, struct url_stat *us,
 FILE *
 fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
 {
-	return (ftp_request(url, "RETR", us, ftp_get_proxy(flags), flags));
+	return (ftp_request(url, "RETR", us, ftp_get_proxy(url, flags), flags));
 }
 
 /*
@@ -1158,9 +1160,8 @@ fetchGetFTP(struct url *url, const char *flags)
 FILE *
 fetchPutFTP(struct url *url, const char *flags)
 {
-
 	return (ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
-	    ftp_get_proxy(flags), flags));
+	    ftp_get_proxy(url, flags), flags));
 }
 
 /*
@@ -1171,9 +1172,10 @@ fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
 {
 	FILE *f;
 
-	f = ftp_request(url, "STAT", us, ftp_get_proxy(flags), flags);
+	f = ftp_request(url, "STAT", us, ftp_get_proxy(url, flags), flags);
 	if (f == NULL)
 		return (-1);
+	fclose(f);
 	return (0);
 }
 
diff --git a/lib/libfetch/http.c b/lib/libfetch/http.c
index 909b91c..c89f5f1 100644
--- a/lib/libfetch/http.c
+++ b/lib/libfetch/http.c
@@ -719,13 +719,15 @@ http_connect(struct url *URL, struct url *purl, const char *flags)
 }
 
 static struct url *
-http_get_proxy(const char *flags)
+http_get_proxy(struct url * url, const char *flags)
 {
 	struct url *purl;
 	char *p;
 
 	if (flags != NULL && strchr(flags, 'd') != NULL)
 		return (NULL);
+	if (fetch_no_proxy_match(url->host))
+		return (NULL);
 	if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
 	    *p && (purl = fetchParseURL(p))) {
 		if (!*purl->scheme)
@@ -1168,7 +1170,7 @@ ouch:
 FILE *
 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
 {
-	return (http_request(URL, "GET", us, http_get_proxy(flags), flags));
+	return (http_request(URL, "GET", us, http_get_proxy(URL, flags), flags));
 }
 
 /*
@@ -1198,7 +1200,7 @@ fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
 {
 	FILE *f;
 
-	f = http_request(URL, "HEAD", us, http_get_proxy(flags), flags);
+	f = http_request(URL, "HEAD", us, http_get_proxy(URL, flags), flags);
 	if (f == NULL)
 		return (-1);
 	fclose(f);