1 /*
2   Copyright 2021 Northern.tech AS
3 
4   This file is part of CFEngine 3 - written and maintained by Northern.tech AS.
5 
6   This program is free software; you can redistribute it and/or modify it
7   under the terms of the GNU General Public License as published by the
8   Free Software Foundation; version 3.
9 
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU General Public License for more details.
14 
15   You should have received a copy of the GNU General Public License
16   along with this program; if not, write to the Free Software
17   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA
18 
19   To the extent this program is licensed as part of the Enterprise
20   versions of CFEngine, the applicable Commercial Open Source License
21   (COSL) may apply to this file if you as a licensee so wish it. See
22   included file COSL.txt.
23 */
24 
25 #include <cf3.defs.h>
26 
27 
28 /*
29  * Cumulative statistics support and conversion to instant values
30  */
31 
32 typedef struct PrevValue_ PrevValue;
33 
34 struct PrevValue_
35 {
36     char *name;
37     char *subname;
38     union
39     {
40         unsigned u32;
41         unsigned long long u64;
42     } value;
43     time_t timestamp;
44     PrevValue *next;
45 };
46 
47 /* Globals */
48 
49 static PrevValue *values;
50 
51 /* Implementation */
52 
AppendNewValue(const char * name,const char * subname,time_t timestamp)53 static PrevValue *AppendNewValue(const char *name, const char *subname, time_t timestamp)
54 {
55     PrevValue *v = xmalloc(sizeof(PrevValue));
56 
57     v->name = xstrdup(name);
58     v->subname = xstrdup(subname);
59     v->timestamp = timestamp;
60     v->next = values;
61     values = v;
62     return v;
63 }
64 
GetInstantUint32Value(const char * name,const char * subname,unsigned value,time_t timestamp)65 unsigned GetInstantUint32Value(const char *name, const char *subname, unsigned value, time_t timestamp)
66 {
67     PrevValue *v;
68 
69     for (v = values; v; v = v->next)
70     {
71         if (!strcmp(v->name, name) && !strcmp(v->subname, subname))
72         {
73             unsigned diff;
74             unsigned difft;
75 
76             /* Check for wraparound */
77             if (value < v->value.u32)
78             {
79                 diff = INT_MAX - v->value.u32 + value;
80             }
81             else
82             {
83                 diff = value - v->value.u32;
84             }
85             difft = timestamp - v->timestamp;
86 
87             v->value.u32 = value;
88             v->timestamp = timestamp;
89 
90             if (difft != 0)
91             {
92                 return diff / difft;
93             }
94             else
95             {
96                 return (unsigned) -1;
97             }
98         }
99     }
100 
101     AppendNewValue(name, subname, timestamp)->value.u32 = value;
102     return (unsigned) -1;
103 }
104 
GetInstantUint64Value(const char * name,const char * subname,unsigned long long value,time_t timestamp)105 unsigned long long GetInstantUint64Value(const char *name, const char *subname, unsigned long long value,
106                                          time_t timestamp)
107 {
108     PrevValue *v;
109 
110     for (v = values; v; v = v->next)
111     {
112         if (!strcmp(v->name, name) && !strcmp(v->subname, subname))
113         {
114             unsigned long long diff = value - v->value.u64;
115             unsigned difft = timestamp - v->timestamp;
116 
117             v->value.u64 = value;
118             v->timestamp = timestamp;
119 
120             if (difft != 0)
121             {
122                 return diff / difft;
123             }
124             else
125             {
126                 return (unsigned long long) -1;
127             }
128         }
129     }
130 
131     AppendNewValue(name, subname, timestamp)->value.u64 = value;
132     return (unsigned long long) -1;
133 }
134