syscalls.cc: unlink_nt: Try FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE

I think we don't need an extra flag as we can utilize: access & FILE_WRITE_ATTRIBUTES
What do you think?

Ben Wijen (1):
  syscalls.cc: unlink_nt: Try FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE

 winsup/cygwin/ntdll.h     |  3 ++-
 winsup/cygwin/syscalls.cc | 22 +++++++--------
 winsup/cygwin/wincap.cc   | 11 ++++++++
 winsup/cygwin/wincap.h    | 56 ++++++++++++++++++++-------------------
 4 files changed, 53 insertions(+), 39 deletions(-)

--
2.30.0

>From 2d0ff6fec10d03c24d11c747852018b7bc1136ac Mon Sep 17 00:00:00 2001
In-Reply-To: <20210122105201.GD810271@calimero.vinschen.de>
References: <20210122105201.GD810271@calimero.vinschen.de>
From: Ben Wijen <ben@wijen.net>
Date: Tue, 17 Dec 2019 15:15:25 +0100
Subject: [PATCH v3 1/8] syscalls.cc: unlink_nt: Try
 FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE

Implement wincap.has_posix_unlink_semantics_with_ignore_readonly and when set
skip setting/clearing of READONLY attribute and instead use
FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE

4 files changed, 53 insertions, 39 deletions

diff --git a/winsup/cygwin/ntdll.h b/winsup/cygwin/ntdll.h
index d4f6aaf45..7eee383dd 100644
--- a/winsup/cygwin/ntdll.h
+++ b/winsup/cygwin/ntdll.h
@@ -497,7 +497,8 @@ enum {
   FILE_DISPOSITION_DELETE				= 0x01,
   FILE_DISPOSITION_POSIX_SEMANTICS			= 0x02,
   FILE_DISPOSITION_FORCE_IMAGE_SECTION_CHECK		= 0x04,
-  FILE_DISPOSITION_ON_CLOSE				= 0x08
+  FILE_DISPOSITION_ON_CLOSE				= 0x08,
+  FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE		= 0x10,
 };
 
 enum
diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc
index c985142eb..b3a110aaa 100644
--- a/winsup/cygwin/syscalls.cc
+++ b/winsup/cygwin/syscalls.cc
@@ -719,7 +719,7 @@ _unlink_nt (path_conv &pc, bool shareable)
 
   pc.get_object_attr (attr, sec_none_nih);
 
-  /* First check if we can use POSIX unlink semantics: W10 1709++, local NTFS.
+  /* First check if we can use POSIX unlink semantics: W10 1709+, local NTFS.
      With POSIX unlink semantics the entire job gets MUCH easier and faster.
      Just try to do it and if it fails, it fails. */
   if (wincap.has_posix_unlink_semantics ()
@@ -727,20 +727,18 @@ _unlink_nt (path_conv &pc, bool shareable)
     {
       FILE_DISPOSITION_INFORMATION_EX fdie;
 
-      if (pc.file_attributes () & FILE_ATTRIBUTE_READONLY)
+      /* POSIX unlink semantics are nice, but they still fail if the file has
+	 the R/O attribute set. If so, ignoring might be an option: W10 1809+
+	 Removing the file is very much a safe bet afterwards, so, no
+	 transaction. */
+      if ((pc.file_attributes () & FILE_ATTRIBUTE_READONLY)
+          && !wincap.has_posix_unlink_semantics_with_ignore_readonly ())
 	access |= FILE_WRITE_ATTRIBUTES;
       status = NtOpenFile (&fh, access, &attr, &io, FILE_SHARE_VALID_FLAGS,
 			   flags);
       if (!NT_SUCCESS (status))
 	goto out;
-      /* Why didn't the devs add a FILE_DELETE_IGNORE_READONLY_ATTRIBUTE
-	 flag just like they did with FILE_LINK_IGNORE_READONLY_ATTRIBUTE
-	 and FILE_LINK_IGNORE_READONLY_ATTRIBUTE???
-
-         POSIX unlink semantics are nice, but they still fail if the file
-	 has the R/O attribute set.  Removing the file is very much a safe
-	 bet afterwards, so, no transaction. */
-      if (pc.file_attributes () & FILE_ATTRIBUTE_READONLY)
+      if (access & FILE_WRITE_ATTRIBUTES)
 	{
 	  status = NtSetAttributesFile (fh, pc.file_attributes ()
 					    & ~FILE_ATTRIBUTE_READONLY);
@@ -751,10 +749,12 @@ _unlink_nt (path_conv &pc, bool shareable)
 	    }
 	}
       fdie.Flags = FILE_DISPOSITION_DELETE | FILE_DISPOSITION_POSIX_SEMANTICS;
+      if (wincap.has_posix_unlink_semantics_with_ignore_readonly ())
+        fdie.Flags |= FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE;
       status = NtSetInformationFile (fh, &io, &fdie, sizeof fdie,
 				     FileDispositionInformationEx);
       /* Restore R/O attribute in case we have multiple hardlinks. */
-      if (pc.file_attributes () & FILE_ATTRIBUTE_READONLY)
+      if (access & FILE_WRITE_ATTRIBUTES)
 	NtSetAttributesFile (fh, pc.file_attributes ());
       NtClose (fh);
       /* Trying to delete in-use executables and DLLs using
diff --git a/winsup/cygwin/wincap.cc b/winsup/cygwin/wincap.cc
index b18e732cd..635e0892b 100644
--- a/winsup/cygwin/wincap.cc
+++ b/winsup/cygwin/wincap.cc
@@ -38,6 +38,7 @@ wincaps wincap_vista __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_unbiased_interrupt_time:false,
     has_precise_interrupt_time:false,
     has_posix_unlink_semantics:false,
+    has_posix_unlink_semantics_with_ignore_readonly:false,
     has_case_sensitive_dirs:false,
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:true,
@@ -72,6 +73,7 @@ wincaps wincap_7 __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:false,
     has_posix_unlink_semantics:false,
+    has_posix_unlink_semantics_with_ignore_readonly:false,
     has_case_sensitive_dirs:false,
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:true,
@@ -106,6 +108,7 @@ wincaps wincap_8 __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:false,
     has_posix_unlink_semantics:false,
+    has_posix_unlink_semantics_with_ignore_readonly:false,
     has_case_sensitive_dirs:false,
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
@@ -140,6 +143,7 @@ wincaps wincap_8_1 __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:false,
     has_posix_unlink_semantics:false,
+    has_posix_unlink_semantics_with_ignore_readonly:false,
     has_case_sensitive_dirs:false,
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
@@ -174,6 +178,7 @@ wincaps  wincap_10_1507 __attribute__((section (".cygwin_dll_common"), shared))
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:true,
     has_posix_unlink_semantics:false,
+    has_posix_unlink_semantics_with_ignore_readonly:false,
     has_case_sensitive_dirs:false,
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
@@ -208,6 +213,7 @@ wincaps  wincap_10_1607 __attribute__((section (".cygwin_dll_common"), shared))
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:true,
     has_posix_unlink_semantics:false,
+    has_posix_unlink_semantics_with_ignore_readonly:false,
     has_case_sensitive_dirs:false,
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
@@ -242,6 +248,7 @@ wincaps wincap_10_1703 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:true,
     has_posix_unlink_semantics:false,
+    has_posix_unlink_semantics_with_ignore_readonly:false,
     has_case_sensitive_dirs:false,
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
@@ -276,6 +283,7 @@ wincaps wincap_10_1709 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:true,
     has_posix_unlink_semantics:true,
+    has_posix_unlink_semantics_with_ignore_readonly:false,
     has_case_sensitive_dirs:false,
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
@@ -310,6 +318,7 @@ wincaps wincap_10_1803 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:true,
     has_posix_unlink_semantics:true,
+    has_posix_unlink_semantics_with_ignore_readonly:false,
     has_case_sensitive_dirs:true,
     has_posix_rename_semantics:false,
     no_msv1_0_s4u_logon_in_wow64:false,
@@ -344,6 +353,7 @@ wincaps wincap_10_1809 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:true,
     has_posix_unlink_semantics:true,
+    has_posix_unlink_semantics_with_ignore_readonly:true,
     has_case_sensitive_dirs:true,
     has_posix_rename_semantics:true,
     no_msv1_0_s4u_logon_in_wow64:false,
@@ -378,6 +388,7 @@ wincaps wincap_10_1903 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_unbiased_interrupt_time:true,
     has_precise_interrupt_time:true,
     has_posix_unlink_semantics:true,
+    has_posix_unlink_semantics_with_ignore_readonly:true,
     has_case_sensitive_dirs:true,
     has_posix_rename_semantics:true,
     no_msv1_0_s4u_logon_in_wow64:false,
diff --git a/winsup/cygwin/wincap.h b/winsup/cygwin/wincap.h
index 2f4191aa1..6be2ca2a1 100644
--- a/winsup/cygwin/wincap.h
+++ b/winsup/cygwin/wincap.h
@@ -16,33 +16,34 @@ struct wincaps
   /* The bitfields must be 8 byte aligned on x86_64, otherwise the bitfield
      ops generated by gcc are off by 4 bytes. */
   struct  __attribute__ ((aligned (8))) {
-    unsigned is_server				: 1;
-    unsigned needs_count_in_si_lpres2		: 1;
-    unsigned needs_query_information		: 1;
-    unsigned has_gaa_largeaddress_bug		: 1;
-    unsigned has_broken_alloc_console		: 1;
-    unsigned has_console_logon_sid		: 1;
-    unsigned has_precise_system_time		: 1;
-    unsigned has_microsoft_accounts		: 1;
-    unsigned has_processor_groups		: 1;
-    unsigned has_broken_prefetchvm		: 1;
-    unsigned has_new_pebteb_region		: 1;
-    unsigned has_broken_whoami			: 1;
-    unsigned has_unprivileged_createsymlink	: 1;
-    unsigned has_unbiased_interrupt_time	: 1;
-    unsigned has_precise_interrupt_time		: 1;
-    unsigned has_posix_unlink_semantics		: 1;
-    unsigned has_case_sensitive_dirs		: 1;
-    unsigned has_posix_rename_semantics		: 1;
-    unsigned no_msv1_0_s4u_logon_in_wow64	: 1;
-    unsigned has_con_24bit_colors		: 1;
-    unsigned has_con_broken_csi3j		: 1;
-    unsigned has_con_broken_il_dl		: 1;
-    unsigned has_con_esc_rep			: 1;
-    unsigned has_extended_mem_api		: 1;
-    unsigned has_tcp_fastopen			: 1;
-    unsigned has_linux_tcp_keepalive_sockopts	: 1;
-    unsigned has_tcp_maxrtms			: 1;
+    unsigned is_server						: 1;
+    unsigned needs_count_in_si_lpres2				: 1;
+    unsigned needs_query_information				: 1;
+    unsigned has_gaa_largeaddress_bug				: 1;
+    unsigned has_broken_alloc_console				: 1;
+    unsigned has_console_logon_sid				: 1;
+    unsigned has_precise_system_time				: 1;
+    unsigned has_microsoft_accounts				: 1;
+    unsigned has_processor_groups				: 1;
+    unsigned has_broken_prefetchvm				: 1;
+    unsigned has_new_pebteb_region				: 1;
+    unsigned has_broken_whoami					: 1;
+    unsigned has_unprivileged_createsymlink			: 1;
+    unsigned has_unbiased_interrupt_time			: 1;
+    unsigned has_precise_interrupt_time				: 1;
+    unsigned has_posix_unlink_semantics				: 1;
+    unsigned has_posix_unlink_semantics_with_ignore_readonly	: 1;
+    unsigned has_case_sensitive_dirs				: 1;
+    unsigned has_posix_rename_semantics				: 1;
+    unsigned no_msv1_0_s4u_logon_in_wow64			: 1;
+    unsigned has_con_24bit_colors				: 1;
+    unsigned has_con_broken_csi3j				: 1;
+    unsigned has_con_broken_il_dl				: 1;
+    unsigned has_con_esc_rep					: 1;
+    unsigned has_extended_mem_api				: 1;
+    unsigned has_tcp_fastopen					: 1;
+    unsigned has_linux_tcp_keepalive_sockopts			: 1;
+    unsigned has_tcp_maxrtms					: 1;
   };
 };
 
@@ -98,6 +99,7 @@ public:
   bool	IMPLEMENT (has_unbiased_interrupt_time)
   bool	IMPLEMENT (has_precise_interrupt_time)
   bool	IMPLEMENT (has_posix_unlink_semantics)
+  bool	IMPLEMENT (has_posix_unlink_semantics_with_ignore_readonly)
   bool	IMPLEMENT (has_case_sensitive_dirs)
   bool	IMPLEMENT (has_posix_rename_semantics)
   bool	IMPLEMENT (no_msv1_0_s4u_logon_in_wow64)