From: Nick Ing-Simmons <nik@tiuk.ti.com>
Date: Tue, 21 Jan 2003 20:22:55 +0000 (+0000)
Subject: Try the invalidate_fileno() idea for non-leaky stdio sockets.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=0d7a53989a672378609205d638df0119542bcf7e;p=p5sagit%2Fp5-mst-13.2.git

Try the invalidate_fileno() idea for non-leaky stdio sockets.

p4raw-id: //depot/perlio@18539
---

diff --git a/perlio.c b/perlio.c
index 2d5785b..996b893 100644
--- a/perlio.c
+++ b/perlio.c
@@ -2684,13 +2684,86 @@ PerlIOStdio_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
     return f;
 }
 
+static int
+PerlIOStdio_invalidate_fileno(pTHX_ FILE *f)
+{
+    /* XXX this could use PerlIO_canset_fileno() and
+     * PerlIO_set_fileno() support from Configure 
+     */
+#  if defined(__GLIBC__)
+    /* There may be a better way for GLIBC:
+    	- libio.h defines a flag to not close() on cleanup 
+     */	
+    f->_fileno = -1;
+    return 1;
+#  elif defined(__sun__)
+#    if defined(_LP64)
+    /* On solaris, if _LP64 is defined, the FILE structure is this:
+     *
+     *  struct FILE {
+     *      long __pad[16];
+     *  };
+     *
+     * It turns out that the fd is stored in the top 32 bits of 
+     * file->__pad[4]. The lower 32 bits contain flags. file->pad[5] appears
+     * to contain a pointer or offset into another structure. All the
+     * remaining fields are zero.
+     *
+     * We set the top bits to -1 (0xFFFFFFFF).
+     */
+    f->__pad[4] |= 0xffffffff00000000L;
+    assert(fileno(f) == 0xffffffff);
+#    else /* !defined(_LP64) */
+    /* _file is just a unsigned char :-( 
+       Not clear why we dup() rather than using -1 
+       even if that would be treated as 0xFF - so will 
+       a dup fail ...
+     */
+    f->_file = PerlLIO_dup(fd);
+#    endif /* defined(_LP64) */
+    return 1;
+#  elif defined(__hpux)
+    f->__fileH = 0xff;
+    f->__fileL = 0xff;
+    return 1;
+#  elif defined(_AIX)
+    f->_file = -1;
+    return 1;
+#  elif defined(__FreeBSD__)
+    /* There may be a better way on FreeBSD:
+        - we could insert a dummy func in the _close function entry 
+	f->_close = (int (*)(void *)) dummy_close; 
+     */
+    f->_file = -1;
+    return 1;
+#  elif defined(__CYGWIN__)
+    /* There may be a better way on CYGWIN:
+        - we could insert a dummy func in the _close function entry 
+	f->_close = (int (*)(void *)) dummy_close; 
+     */
+    f->_file = -1;
+    return 1;
+#  elif defined(WIN32)
+#    if defined(__BORLANDC__)
+    f->fd = PerlLIO_dup(fileno(f));
+#    else
+    f->_file = -1;
+#    endif
+    return 1;
+#  else
+#if 0
+    /* Sarathy's code did this - we fall back to a dup/dup2 hack 
+       (which isn't thread safe) instead
+     */  
+#    error "Don't know how to set FILE.fileno on your platform"
+#endif
+    return 0;
+#  endif
+}
+
 IV
 PerlIOStdio_close(pTHX_ PerlIO *f)
 {
-#ifdef SOCKS5_VERSION_NAME
-    int optval;
-    Sock_size_t optlen = sizeof(int);
-#endif
     FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
     if (!stdio) {
 	errno = EBADF;
@@ -2698,52 +2771,66 @@ PerlIOStdio_close(pTHX_ PerlIO *f)
     }
     else {
         int fd = fileno(stdio);
-	int dupfd = -1;
+	int socksfd = 0;
+	int invalidate = 0;
 	IV result;
+	int saveerr = 0;
+	int dupfd = 0;
+#ifdef SOCKS5_VERSION_NAME
+    	/* Socks lib overrides close() but stdio isn't linked to 
+	   that library (though we are) - so we must call close() 
+	   on sockets on stdio's behalf. 
+	 */   
+    	int optval;
+    	Sock_size_t optlen = sizeof(int);
+    	if (getsockopt(fd, SOL_SOCKET, SO_TYPE, (void *) &optval, &optlen) == 0) {
+            socksfd = 1;
+	    invalidate = 1;  
+    	}
+#endif
     	if (PerlIOUnix_refcnt_dec(fd) > 0) {
 	    /* File descriptor still in use */
-	    if (fd < 3) {
-	    	/* For STD* handles don't close the stdio at all */
+	    invalidate = 1;
+	    socksfd = 0;
+	}    
+	if (invalidate) {
+   	    /* For STD* handles don't close the stdio at all 
+	       this is because we have shared the FILE * too 
+   	     */
+	    if (stdio == stdin) {
+	    	/* Some stdios are buggy fflush-ing inputs */
+	    	return 0;
+	    }
+	    else if (stdio == stdout || stdio == stderr) {
 	    	return PerlIO_flush(f);
 	    }
-	    else {
-            	/* Tricky - must fclose(stdio) to free memory but not close(fd) */ 
-#ifdef USE_THREADS
-    	    	/* Sarathy pointed out that another thread could reuse
-		   fd after fclose() but before we dup2() below
-		   so take out a MUTEX to shut them out 
-		 */  
-    	    	MUTEX_LOCK(&PerlIO_mutex);
-#endif
+            /* Tricky - must fclose(stdio) to free memory but not close(fd) 
+	       Use Sarathy's trick from maint-5.6 to invalidate the 
+	       fileno slot of the FILE * 
+	    */ 
+	    saveerr = errno;
+    	    if (!(invalidate = PerlIOStdio_invalidate_fileno(aTHX_ stdio))) {
 	    	dupfd = PerlLIO_dup(fd);
 	    }
-	}    
-        result = (
-#ifdef SOCKS5_VERSION_NAME
-	       (getsockopt
-		(PerlIO_fileno(f), SOL_SOCKET, SO_TYPE, (void *) &optval,
-		 &optlen) <
-		0) ? PerlSIO_fclose(stdio) : close(PerlIO_fileno(f))
-#else
-	       PerlSIO_fclose(stdio)
-#endif
-	);
-	if (dupfd >= 0) {
-	    /* We need to restore fd from the saved copy */
-	    if (PerlLIO_dup2(dupfd,fd) != fd)
-	      result = -1;
-#ifdef USE_THREADS
-    	    MUTEX_UNLOCK(&PerlIO_mutex);
-#endif
-	    if (PerlLIO_close(dupfd) != 0)
-	      result = -1; 
+	} 
+        result = PerlSIO_fclose(stdio);
+	/* We treat EBADF from stdio as success if we invalidated */
+	if (invalidate && result != 0 && errno == EBADF) {
+	    errno = saveerr;
+	    result = 0;
+	} 
+	if (socksfd) {
+	    /* in SOCKS case let close() determine return value */
+	    result = close(fd);
+	}
+	if (dupfd) {
+	    PerlLIO_dup2(dupfd,fd);
+	    close(dupfd);
 	}
 	return result;
     } 
 }
 
-
-
 SSize_t
 PerlIOStdio_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
 {