Ignore errno for GNU TLS read/write handlers.

Author: michaelrsweet

CHANGES.md

@@ -12,6 +12,7 @@ v3.0.1 - YYYY-MM-DD
 - Updated `cupsRasterReadHeader` to validate more of the page header values.
 - Fixed a bug when the `ippFindXxx` and `ippSetXxx` functions were mixed
   (Issue #138)
+- Fixed error handling in the low-level TLS read/write functions.
 
 
 v3.0.0 - 2026-01-08

cups/tls-gnutls.c

@@ -1616,7 +1616,7 @@ _httpTLSRead(http_t *http,		// I - Connection to server
 
   result = gnutls_record_recv(http->tls, buf, (size_t)len);
 
-  if (result < 0 && !errno)
+  if (result < 0)
   {
     // Convert GNU TLS error to errno value...
     switch (result)
@@ -2025,7 +2025,7 @@ _httpTLSWrite(http_t     *http,		// I - Connection to server
 
   result = gnutls_record_send(http->tls, buf, (size_t)len);
 
-  if (result < 0 && !errno)
+  if (result < 0)
   {
     // Convert GNU TLS error to errno value...
     switch (result)

cups/tls-openssl.c

@@ -3,7 +3,7 @@
 //
 // Note: This file is included from tls.c
 //
-// Copyright © 2020-2025 by OpenPrinting
+// Copyright © 2020-2026 by OpenPrinting
 // Copyright © 2007-2019 by Apple Inc.
 // Copyright © 1997-2007 by Easy Software Products, all rights reserved.
 //
@@ -1718,9 +1718,17 @@ _httpTLSRead(http_t *http,		// I - Connection to server
   int bytes = SSL_read((SSL *)(http->tls), buf, len);
 					// Bytes read
 
-  DEBUG_printf("7_httpTLSRead(http=%p, buf=%p, len=%d) returning %d", (void *)http, (void *)buf, len, bytes);
+  DEBUG_printf("7_httpTLSRead(http=%p, buf=%p, len=%d) got %d", (void *)http, (void *)buf, len, bytes);
 
-  return (bytes);
+  if (bytes > 0)
+    return (bytes);
+
+  if (SSL_get_error(http->tls, bytes) == SSL_ERROR_WANT_READ)
+    errno = EAGAIN;
+  else
+    errno = EPIPE;
+
+  return (-1);
 }
 
 
@@ -2053,7 +2061,20 @@ _httpTLSWrite(http_t     *http,		// I - Connection to server
 	      const char *buf,		// I - Buffer holding data
 	      int        len)		// I - Length of buffer
 {
-  return (SSL_write(http->tls, buf, len));
+  int bytes = SSL_write(http->tls, buf, len);
+					// Bytes written
+
+  DEBUG_printf("7_httpTLSWrite(http=%p, buf=%p, len=%d) got %d", (void *)http, (void *)buf, len, bytes);
+
+  if (bytes > 0)
+    return (bytes);
+
+  if (SSL_get_error(http->tls, bytes) == SSL_ERROR_WANT_WRITE)
+    errno = EAGAIN;
+  else
+    errno = EPIPE;
+
+  return (-1);
 }
 
 

xcode/libcups.xcodeproj/project.pbxproj

@@ -1291,7 +1291,7 @@
 		273BF6C61333B5370022CAAB /* testcups.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; name = testcups.c; path = ../cups/testcups.c; sourceTree = "<group>"; };
 		274265BC2C08EC5200510CD4 /* oauth.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; name = oauth.c; path = ../cups/oauth.c; sourceTree = "<group>"; };
 		274265BD2C08EC5200510CD4 /* oauth.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = oauth.h; path = ../cups/oauth.h; sourceTree = "<group>"; };
-		274561471F545B2E000378E4 /* cupspm.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; name = cupspm.md; path = ../cups/cupspm.md; sourceTree = "<group>"; };
+		274561471F545B2E000378E4 /* cupspm3.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; name = cupspm3.md; path = ../cups/cupspm3.md; sourceTree = "<group>"; };
 		2746EBD429DCD74E006A82B1 /* testhash */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = testhash; sourceTree = BUILT_PRODUCTS_DIR; };
 		2746EBD729DCD79A006A82B1 /* testhash.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; name = testhash.c; path = ../cups/testhash.c; sourceTree = "<group>"; };
 		274770E02345342B0089BC31 /* testthreads */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = testthreads; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -2182,7 +2182,7 @@
 			children = (
 				72E65BDE18DCA35700097E89 /* CHANGES.md */,
 				72E65BDF18DCA35700097E89 /* CREDITS.md */,
-				274561471F545B2E000378E4 /* cupspm.md */,
+				274561471F545B2E000378E4 /* cupspm3.md */,
 				72E65BB918DC7A3600097E89 /* doc */,
 				72E65BE018DCA35700097E89 /* INSTALL.md */,
 				72E65BE218DCA35700097E89 /* LICENSE */,