[PATCH] handle EPROTOTYPE for socket invocations with SOCK_* flags

[Pino Toscano <toscano dot pino at tiscali dot it>]

Hi,

since glibc 2.16, Hurd's bits/socket.h provides SOCK_CLOEXEC and 
SOCK_NONBLOCK (which accept4 handles), but __ASSUME_SOCK_CLOEXEC is not 
defined since socket and socketpair do not handle them, yet.

The snippets of fallback code that handle failures of invocation of 
socket with SOCK_CLOEXEC or SOCK_NONBLOCK seem to not correctly disable 
have_sock_cloexec/__have_sock_cloexec if errno is EPROTOTYPE, as 
returned when the socket type (like "SOCK_STREAM | SOCK_CLOEXEC" for 
socket with no handling of flags) is unknown.

The attached patch handles EPROTOTYPE as if it was EINVAL, disabling 
have_sock_cloexec/__have_sock_cloexec if socket does not handle SOCK_* 
flags.

(OTOH, it seems that there are few Linux archs -- like mips*, arm, hppa, 
m68k -- which don't have __ASSUME_SOCK_CLOEXEC enabled in their
kernel-features.h at all: does it mean the Linux kernel really returns 
EINVAL for unknown values as socket types?)

Thanks,
-- 
Pino Toscano

Handle EPROTOTYPE for socket invocations with SOCK_* flags

If SOCK_CLOEXEC and SOCK_NONBLOCK are defined but not __ASSUME_SOCK_CLOEXEC,
trying to use them as socket type in invocations of socket will return
EPROTOTYPE if socket and socketpair do not handle those flags; EPROTOTYPE is
not considered properly, behaving as if those flags were actually supported.

Checking for the EPROTOTYPE errno in addition to EINVAL handles the situation.

2013-02-06  Pino Toscano  <toscano.pino@tiscali.it>

	* nscd/connections.c (nscd_init) [!defined __ASSUME_SOCK_CLOEXEC]:
	Check for EPROTOTYPE in addition to EINVAL.
	* nscd/nscd_helper.c (open_socket) [defined SOCK_CLOEXEC]
	[!defined __ASSUME_SOCK_CLOEXEC]: Likewise.
	* resolv/res_send.c (reopen) [!defined __ASSUME_SOCK_CLOEXEC]: Likewise.
	* sunrpc/clnt_udp.c (__libc_clntudp_bufcreate) [defined SOCK_NONBLOCK]
	[!defined __ASSUME_SOCK_CLOEXEC]: Likewise.
	* misc/syslog.c (openlog_internal) [defined SOCK_CLOEXEC]
	[!defined __ASSUME_SOCK_CLOEXEC]: Likewise.

--- a/nscd/connections.c
+++ b/nscd/connections.c
@@ -856,7 +856,7 @@ cannot set socket to close on exec: %s;
       sock = socket (AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
 #ifndef __ASSUME_SOCK_CLOEXEC
       if (have_sock_cloexec == 0)
-	have_sock_cloexec = sock != -1 || errno != EINVAL ? 1 : -1;
+	have_sock_cloexec = sock != -1 || (errno != EINVAL && errno != EPROTOTYPE) ? 1 : -1;
 #endif
     }
 #ifndef __ASSUME_SOCK_CLOEXEC
--- a/nscd/nscd_helper.c
+++ b/nscd/nscd_helper.c
@@ -172,7 +172,7 @@ open_socket (request_type type, const ch
       sock = __socket (PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
 # ifndef __ASSUME_SOCK_CLOEXEC
       if (__have_sock_cloexec == 0)
-	__have_sock_cloexec = sock != -1 || errno != EINVAL ? 1 : -1;
+	__have_sock_cloexec = sock != -1 || (errno != EINVAL && errno != EPROTOTYPE) ? 1 : -1;
 # endif
     }
 #endif
--- a/resolv/res_send.c
+++ b/resolv/res_send.c
@@ -925,7 +925,7 @@ reopen (res_state statp, int *terrno, in
 				if (__have_o_nonblock == 0)
 					__have_o_nonblock
 					  = (EXT(statp).nssocks[ns] == -1
-					     && errno == EINVAL ? -1 : 1);
+					     && (errno == EINVAL || errno == EPROTOTYPE) ? -1 : 1);
 #endif
 			}
 			if (__builtin_expect (__have_o_nonblock < 0, 0))
@@ -943,7 +943,7 @@ reopen (res_state statp, int *terrno, in
 				if (__have_o_nonblock == 0)
 					__have_o_nonblock
 					  = (EXT(statp).nssocks[ns] == -1
-					     && errno == EINVAL ? -1 : 1);
+					     && (errno == EINVAL || errno == EPROTOTYPE) ? -1 : 1);
 #endif
 			}
 			if (__builtin_expect (__have_o_nonblock < 0, 0))
--- a/sunrpc/clnt_udp.c
+++ b/sunrpc/clnt_udp.c
@@ -179,7 +179,7 @@ __libc_clntudp_bufcreate (struct sockadd
 			     IPPROTO_UDP);
 # ifndef __ASSUME_SOCK_CLOEXEC
 	  if (__have_sock_cloexec == 0)
-	    __have_sock_cloexec = *sockp >= 0 || errno != EINVAL ? 1 : -1;
+	    __have_sock_cloexec = *sockp >= 0 || (errno != EINVAL && errno != EPROTOTYPE) ? 1 : -1;
 # endif
 	}
 #endif
--- a/misc/syslog.c
+++ b/misc/syslog.c
@@ -357,7 +357,7 @@ openlog_internal(const char *ident, int
 					if (__have_sock_cloexec == 0)
 						__have_sock_cloexec
 						  = ((LogFile != -1
-						      || errno != EINVAL)
+						      || (errno != EINVAL && errno != EPROTOTYPE))
 						     ? 1 : -1);
 				}
 # endif

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