[reactos] 01/01: [NTOS:EX] Clarify the situation with the SystemPathInformation class. (#4065)

[Hermès Bélusca-Maïto]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=712f469671a339b29ccd9…

commit 712f469671a339b29ccd9b4e4cb61ae435098286
Author:     Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
AuthorDate: Sun Oct 24 18:57:52 2021 +0200
Commit:     Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
CommitDate: Thu Nov 18 22:37:54 2021 +0100

    [NTOS:EX] Clarify the situation with the SystemPathInformation class. (#4065)
    
    Since NT 3.51, this information class is trivially implemented.
    The path to the NT directory is now stored in KUSER_SHARED_DATA
    as the NtSystemRoot member.
    Windows Checked builds show the following message and break to
    the debugger before failing the function as not implemented:
    
    EX: SystemPathInformation now available via SharedUserData
    
    See
https://www.geoffchappell.com/studies/windows/km/ntoskrnl/api/ex/sysinfo/qu…
    and
https://www.geoffchappell.com/studies/windows/km/ntoskrnl/inc/api/ntexapi_x…
    for more information.
---
 ntoskrnl/ex/sysinfo.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/ntoskrnl/ex/sysinfo.c b/ntoskrnl/ex/sysinfo.c
index bb037466850..7fcc3e8260d 100644
--- a/ntoskrnl/ex/sysinfo.c
+++ b/ntoskrnl/ex/sysinfo.c
@@ -861,13 +861,21 @@ QSI_DEF(SystemTimeOfDayInformation)
     return STATUS_SUCCESS;
 }
 
-/* Class 4 - Path Information */
+/* Class 4 - Path Information (DEPRECATED) */
 QSI_DEF(SystemPathInformation)
 {
-    /* FIXME: QSI returns STATUS_BREAKPOINT. Why? */
-    DPRINT1("NtQuerySystemInformation - SystemPathInformation not
implemented\n");
-
-    return STATUS_BREAKPOINT;
+    /*
+     * Since NT 3.51, this information class is trivially implemented.
+     * The path to the NT directory is now stored in KUSER_SHARED_DATA
+     * as the NtSystemRoot member.
+     * Windows Checked builds show the following message and break to
+     * the debugger before failing the function as not implemented.
+     */
+#if DBG
+    DPRINT1("EX: SystemPathInformation now available via SharedUserData\n");
+    // DbgBreakPoint(); // Not needed in ReactOS.
+#endif
+    return STATUS_NOT_IMPLEMENTED;
 }
 
 /* Class 5 - Process Information */
@@ -2830,7 +2838,7 @@ CallQS[] =
     SI_QX(SystemProcessorInformation),
     SI_QX(SystemPerformanceInformation),
     SI_QX(SystemTimeOfDayInformation),
-    SI_QX(SystemPathInformation), /* should be SI_XX */
+    SI_QX(SystemPathInformation),
     SI_QX(SystemProcessInformation),
     SI_QX(SystemCallCountInformation),
     SI_QX(SystemDeviceInformation),