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Re: gethostbyname threadsafe

From: Victor J. Orlikowski <v.j.orlikowski(at)gte.net>
Date: Mon Jul 30 2001 - 17:40:38 EDT

So, I got told the proper way to do things. ;) At any rate, here is a patch to get rid of gethostbyname(). Please review; if no-one screams within 24 hours or so, I'll commit. NOTE: This is not quite IPv6 safe. There are a lot of IPv4 assumptions made in the proxy. If no-one beats be to fixing them (after I commit this), I'll take care of it.

Index: modules/proxy/mod_proxy.c

RCS file: /home/cvs/httpd-proxy/module-2.0/mod_proxy.c,v retrieving revision 1.49

diff -u -d -r1.49 mod_proxy.c
--- modules/proxy/mod_proxy.c	2001/07/09 06:35:51	1.49
+++ modules/proxy/mod_proxy.c	2001/07/30 21:31:43
@@ -615,7 +615,7 @@
     if (!found) {
 	New = apr_array_push(conf->dirconn);
         New->name = apr_pstrdup(parms->pool, arg);
-	New->hostentry = NULL;
+	New->hostaddr = NULL;
 
 	if (ap_proxy_is_ipaddr(New, parms->pool)) {

#if DEBUGGING
Index: modules/proxy/mod_proxy.h

RCS file: /home/cvs/httpd-proxy/module-2.0/mod_proxy.h,v retrieving revision 1.53

diff -u -d -r1.53 mod_proxy.h
--- modules/proxy/mod_proxy.h	2001/06/06 21:51:56	1.53
+++ modules/proxy/mod_proxy.h	2001/07/30 21:31:43

@@ -150,7 +150,7 @@
struct dirconn_entry {

     char *name;
     struct in_addr addr, mask;

- struct hostent *hostentry;

+ struct apr_sockaddr_t *hostaddr;

int (*matcher) (struct dirconn_entry * This, request_rec *r); };

@@ -244,7 +244,6 @@

 PROXY_DECLARE(char *)ap_proxy_removestr(apr_pool_t *pool, const char *list, const char *val);
 PROXY_DECLARE(int) ap_proxy_hex2sec(const char *x);
 PROXY_DECLARE(void) ap_proxy_sec2hex(int t, char *y);
-PROXY_DECLARE(const char *)ap_proxy_host2addr(const char *host, struct hostent *reqhp);
 PROXY_DECLARE(int) ap_proxyerror(request_rec *r, int statuscode, const char *message);
 PROXY_DECLARE(int) ap_proxy_is_ipaddr(struct dirconn_entry *This, apr_pool_t *p);
 PROXY_DECLARE(int) ap_proxy_is_domainname(struct dirconn_entry *This, apr_pool_t *p);

Index: modules/proxy/proxy_util.c

RCS file: /home/cvs/httpd-proxy/module-2.0/proxy_util.c,v retrieving revision 1.63

diff -u -d -r1.63 proxy_util.c
--- modules/proxy/proxy_util.c	2001/06/28 12:48:57	1.63
+++ modules/proxy/proxy_util.c	2001/07/30 21:31:44

@@ -64,7 +64,6 @@

 static int proxy_match_domainname(struct dirconn_entry *This, request_rec *r);
 static int proxy_match_hostname(struct dirconn_entry *This, request_rec *r);
 static int proxy_match_word(struct dirconn_entry *This, request_rec *r);

-static struct per_thread_data *get_per_thread_data(void);

/* already called in the knowledge that the characters are hex digits */ PROXY_DECLARE(int) ap_proxy_hex2c(const char *x) @@ -595,42 +594,6 @@

return statuscode;
}

-/*
- * This routine returns its own error message
- */
-PROXY_DECLARE(const char *)ap_proxy_host2addr(const char *host, struct hostent *reqhp)
-{

- int i;

struct hostent *hp;
struct per_thread_data *ptd = get_per_thread_data(); -
for (i = 0; host[i] != '\0'; i++)
if (!apr_isdigit(host[i]) && host[i] != '.')
break; -
if (host[i] != '\0') {
hp = gethostbyname(host);
if (hp == NULL)
return "Host not found";
}
else {
ptd->ipaddr = ap_inet_addr(host);
hp = gethostbyaddr((char *) &ptd->ipaddr, sizeof(ptd->ipaddr), AF_INET);
if (hp == NULL) {
memset(&ptd->hpbuf, 0, sizeof(ptd->hpbuf));
ptd->hpbuf.h_name = 0;
ptd->hpbuf.h_addrtype = AF_INET;
ptd->hpbuf.h_length = sizeof(ptd->ipaddr);
ptd->hpbuf.h_addr_list = ptd->charpbuf;
ptd->hpbuf.h_addr_list[0] = (char *) &ptd->ipaddr;
ptd->hpbuf.h_addr_list[1] = 0;
hp = &ptd->hpbuf;
}
}
*reqhp = *hp;
return NULL; -} - static const char * proxy_get_host_of_request(request_rec *r) { @@ -766,12 +729,8 @@ /* Return TRUE if addr represents an IP address (or an IP network address) */ static int proxy_match_ipaddr(struct dirconn_entry *This, request_rec *r) {
int i;
int ip_addr[4];
struct in_addr addr;
struct in_addr *ip_list;
char **ip_listptr;
const char *found; + int i, ip_addr[4]; + struct in_addr addr, *ip; const char *host = proxy_get_host_of_request(r);

if (host == NULL) /* oops! */
@@ -807,48 +766,46 @@
#endif

     }
     else {
-	struct hostent the_host;
-
-	memset(&the_host, '\0', sizeof the_host);
-	found = ap_proxy_host2addr(host, &the_host);
+	struct apr_sockaddr_t *reqaddr;
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-	if (found != NULL) {
+        if (apr_sockaddr_info_get(&reqaddr, host, APR_UNSPEC, 0, 0, r->pool)
+	    != APR_SUCCESS) {
 #if DEBUGGING


-        ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,


-                         "2)IP-NoMatch: hostname=%s msg=%s", host, found);


+	    ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
+			 "2)IP-NoMatch: hostname=%s msg=Host not found", 
+			 host);
 #endif
 	    return 0;
 	}
 
-	if (the_host.h_name != NULL)
-	    found = the_host.h_name;
-	else
-	    found = host;
-
 	/* Try to deal with multiple IP addr's for a host */
-	for (ip_listptr = the_host.h_addr_list; *ip_listptr; ++ip_listptr) {
-	    ip_list = (struct in_addr *) *ip_listptr;
-	    if (This->addr.s_addr == (ip_list->s_addr & This->mask.s_addr)) {
+	/* FIXME: This needs to be able to deal with IPv6 */
+	while (reqaddr) {
+	    ip = (struct in_addr *) reqaddr->ipaddr_ptr;
+	    if (This->addr.s_addr == (ip->s_addr & This->mask.s_addr)) {
 #if DEBUGGING

-        ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,

-                       "3)IP-Match: %s[%s] <-> ", found, inet_ntoa(*ip_list));

-        ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,

-                       "%s/", inet_ntoa(This->addr));

-        ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,


-                       "%s", inet_ntoa(This->mask));


+		ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
+			     "3)IP-Match: %s[%s] <-> ", host, 
+			     inet_ntoa(*ip));
+		ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
+			     "%s/", inet_ntoa(This->addr));
+		ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
+			     "%s", inet_ntoa(This->mask));
 #endif
 		return 1;
 	    }
 #if DEBUGGING
 	    else {
                 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,


-                       "3)IP-NoMatch: %s[%s] <-> ", found, inet_ntoa(*ip_list));


+			     "3)IP-NoMatch: %s[%s] <-> ", host, 
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+			     inet_ntoa(*ip));
                 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,


-                       "%s/", inet_ntoa(This->addr));


+			     "%s/", inet_ntoa(This->addr));
                 ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,


-                       "%s", inet_ntoa(This->mask));


+			     "%s", inet_ntoa(This->mask));
 	    }
 #endif
+	    reqaddr = reqaddr->next;
 	}
     }
 
@@ -908,81 +865,29 @@
     return h_len > d_len
 	&& strncasecmp(&host[h_len - d_len], This->name, d_len) == 0;

}

-
-/* Create a copy of a "struct hostent" record; it was presumably returned
- * from a call to gethostbyname() and lives in static storage.
- * By creating a copy we can tuck it away for later use.
- */
-static struct hostent * pduphostent(apr_pool_t *p, const struct hostent *hp)
-{

-    struct hostent *newent;

-    char	  **ptrs;

-    char	  **aliases;

-    struct in_addr *addrs;


-    int		   i = 0, j = 0;


-


-    if (hp == NULL)


-	return NULL;
-

- /* Count number of alias entries */

if (hp->h_aliases != NULL)
for (; hp->h_aliases[j] != NULL; ++j)
continue; -
/* Count number of in_addr entries */
if (hp->h_addr_list != NULL)
for (; hp->h_addr_list[i] != NULL; ++i)
continue; -
/* Allocate hostent structure, alias ptrs, addr ptrs, addrs */
newent = (struct hostent *) apr_palloc(p, sizeof(*hp));
aliases = (char **) apr_palloc(p, (j+1) * sizeof(char*));
ptrs = (char **) apr_palloc(p, (i+1) * sizeof(char*));
addrs = (struct in_addr *) apr_palloc(p, (i+1) * sizeof(struct in_addr)); -
*newent = *hp;
newent->h_name = apr_pstrdup(p, hp->h_name);
newent->h_aliases = aliases;
newent->h_addr_list = (char**) ptrs; -
/* Copy Alias Names: */
for (j = 0; hp->h_aliases[j] != NULL; ++j) {
aliases[j] = apr_pstrdup(p, hp->h_aliases[j]);
}
aliases[j] = NULL; -
/* Copy address entries */
for (i = 0; hp->h_addr_list[i] != NULL; ++i) {
ptrs[i] = (char*) &addrs[i];
addrs[i] = *(struct in_addr *) hp->h_addr_list[i];
}
ptrs[i] = NULL; -
return newent; -}

Do you need help?

-/* Return TRUE if addr represents a host name */ +/* Return TRUE if host represents a host name */ PROXY_DECLARE(int) ap_proxy_is_hostname(struct dirconn_entry *This, apr_pool_t *p) {
- struct hostent host;

char *addr = This->name; + struct apr_sockaddr_t *addr; + char *host = This->name; int i;

/* Host names must not start with a '.' */
- if (addr[0] == '.')

+ if (host[0] == '.')

return 0;

/* rfc1035 says DNS names must consist of "[-a-zA-Z0-9]" and '.' */
- for (i = 0; apr_isalnum(addr[i]) || addr[i] == '-' || addr[i] == '.'; ++i);
+ for (i = 0; apr_isalnum(host[i]) || host[i] == '-' || host[i] == '.'; ++i);

if (addr[i] != '\0' || ap_proxy_host2addr(addr, &host) != NULL) + if (host[i] != '\0' || apr_sockaddr_info_get(&addr, host, APR_UNSPEC, 0, 0, p) != APR_SUCCESS) return 0; -
This->hostentry = pduphostent (p, &host); + + This->hostaddr = addr;

/* Strip trailing dots */
- for (i = strlen(addr) - 1; i > 0 && addr[i] == '.'; --i)
- addr[i] = '\0';
+ for (i = strlen(host) - 1; i > 0 && host[i] == '.'; --i) + host[i] = '\0';

     This->matcher = proxy_match_hostname;
     return 1;
@@ -1003,12 +908,14 @@
     h1_len = strlen(host);

#if 0
- unsigned long *ip_list;

+ struct apr_sockaddr_t *addr = *This->hostaddr;

/* Try to deal with multiple IP addr's for a host */
- for (ip_list = *This->hostentry->h_addr_list; *ip_list != 0UL; ++ip_list)
- if (*ip_list == ? ? ? ? ? ? ? ? ? ? ? ? ?) + while (addr) {

+	if (addr->ipaddr_ptr == ? ? ? ? ? ? ? ? ? ? ? ? ?)
 	    return 1;
+	addr = addr->next;

+ }
#endif

/* Ignore trailing dots in host2 comparison: */ @@ -1182,8 +1089,3 @@
}

Can't find what you're looking for?

#endif

-
-static struct per_thread_data *get_per_thread_data(void)
-{

- return NULL;

-}

Victor

-- 
Victor J. Orlikowski   | The Wall is Down, But the Threat Remains!
==================================================================
v.j.orlikowski@gte.net | orlikowski@apache.org | vjo@us.ibm.com

Received on Mon Jul 30 21:40:38 2001

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