xref: /reactos/ntoskrnl/ke/config.c (revision b09b5584) 
1 /*
2  * PROJECT:         ReactOS Kernel
3  * LICENSE:         GPL - See COPYING in the top level directory
4  * FILE:            ntoskrnl/ke/config.c
5  * PURPOSE:         Configuration Tree Routines
6  * PROGRAMMERS:     Alex Ionescu (alex.ionescu@reactos.org)
7  */
8 
9 /* INCLUDES ******************************************************************/
10 
11 #include <ntoskrnl.h>
12 #define NDEBUG
13 #include <debug.h>
14 
15 /* FUNCTIONS *****************************************************************/
16 
17 /*
18  * @implemented
19  */
20 PCONFIGURATION_COMPONENT_DATA
21 NTAPI
22 KeFindConfigurationEntry(IN PCONFIGURATION_COMPONENT_DATA Child,
23                          IN CONFIGURATION_CLASS Class,
24                          IN CONFIGURATION_TYPE Type,
25                          IN PULONG ComponentKey OPTIONAL)
26 {
27     PCONFIGURATION_COMPONENT_DATA NextLink = NULL;
28 
29     /* Start Search at Root */
30     return KeFindConfigurationNextEntry(Child,
31                                         Class,
32                                         Type,
33                                         ComponentKey,
34                                         &NextLink);
35 }
36 
37 /*
38  * @implemented
39  */
40 PCONFIGURATION_COMPONENT_DATA
41 NTAPI
42 KeFindConfigurationNextEntry(IN PCONFIGURATION_COMPONENT_DATA Child,
43                              IN CONFIGURATION_CLASS Class,
44                              IN CONFIGURATION_TYPE Type,
45                              IN PULONG ComponentKey OPTIONAL,
46                              IN PCONFIGURATION_COMPONENT_DATA *NextLink)
47 {
48     ULONG Key = 0;
49     ULONG Mask = 0;
50     PCONFIGURATION_COMPONENT_DATA Sibling;
51     PCONFIGURATION_COMPONENT_DATA ReturnEntry;
52 
53     /* If we did get a key, then use it instead */
54     if (ComponentKey)
55     {
56         Key = *ComponentKey;
57         Mask = -1;
58     }
59 
60     /* Loop the Components until we find a a match */
61     while (Child)
62     {
63         /* Check if we are starting somewhere already */
64         if (*NextLink)
65         {
66             /* If we've found the place where we started, clear and continue */
67             if (Child == *NextLink) *NextLink = NULL;
68         }
69         else
70         {
71             /* Try to get a match */
72             if ((Child->ComponentEntry.Class) == Class &&
73                 (Child->ComponentEntry.Type) == Type &&
74                 (Child->ComponentEntry.Key & Mask) == Key)
75             {
76                 /* Match found */
77                 return Child;
78             }
79         }
80 
81         /* Now we've also got to lookup the siblings */
82         Sibling = Child->Sibling;
83         while (Sibling)
84         {
85             /* Check if we are starting somewhere already */
86             if (*NextLink)
87             {
88                 /* If we've found the place where we started, clear and continue */
89                 if (Sibling == *NextLink) *NextLink = NULL;
90             }
91             else
92             {
93                 /* Try to get a match */
94                 if ((Sibling->ComponentEntry.Class == Class) &&
95                     (Sibling->ComponentEntry.Type == Type) &&
96                     (Sibling->ComponentEntry.Key & Mask) == Key)
97                 {
98                     /* Match found */
99                     return Sibling;
100                 }
101             }
102 
103             /* We've got to check if the Sibling has a Child as well */
104             if (Sibling->Child)
105             {
106                 /* We're just going to call ourselves again */
107                 ReturnEntry = KeFindConfigurationNextEntry(Sibling->Child,
108                                                            Class,
109                                                            Type,
110                                                            ComponentKey,
111                                                            NextLink);
112                 if (ReturnEntry) return ReturnEntry;
113             }
114 
115             /* Next Sibling */
116             Sibling = Sibling->Sibling;
117         }
118 
119         /* Next Child */
120         Child = Child->Child;
121     }
122 
123     /* If we got here, nothing was found */
124     return NULL;
125 }
126