lib:tdb: Add FALL_THROUGH statements in common/summary.c
[samba.git] / lib / tdb / common / summary.c
1  /*
2    Trivial Database: human-readable summary code
3    Copyright (C) Rusty Russell 2010
4
5    This library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 3 of the License, or (at your option) any later version.
9
10    This library 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 GNU
13    Lesser General Public License for more details.
14
15    You should have received a copy of the GNU Lesser General Public
16    License along with this library; if not, see <http://www.gnu.org/licenses/>.
17 */
18 #include "tdb_private.h"
19
20 #define SUMMARY_FORMAT \
21         "Size of file/data: %llu/%zu\n" \
22         "Header offset/logical size: %zu/%zu\n" \
23         "Number of records: %zu\n" \
24         "Incompatible hash: %s\n" \
25         "Active/supported feature flags: 0x%08x/0x%08x\n" \
26         "Robust mutexes locking: %s\n" \
27         "Smallest/average/largest keys: %zu/%zu/%zu\n" \
28         "Smallest/average/largest data: %zu/%zu/%zu\n" \
29         "Smallest/average/largest padding: %zu/%zu/%zu\n" \
30         "Number of dead records: %zu\n" \
31         "Smallest/average/largest dead records: %zu/%zu/%zu\n" \
32         "Number of free records: %zu\n" \
33         "Smallest/average/largest free records: %zu/%zu/%zu\n" \
34         "Number of hash chains: %zu\n" \
35         "Smallest/average/largest hash chains: %zu/%zu/%zu\n" \
36         "Number of uncoalesced records: %zu\n" \
37         "Smallest/average/largest uncoalesced runs: %zu/%zu/%zu\n" \
38         "Percentage keys/data/padding/free/dead/rechdrs&tailers/hashes: %.0f/%.0f/%.0f/%.0f/%.0f/%.0f/%.0f\n"
39
40 /* We don't use tally module, to keep upstream happy. */
41 struct tally {
42         size_t min, max, total;
43         size_t num;
44 };
45
46 static void tally_init(struct tally *tally)
47 {
48         tally->total = 0;
49         tally->num = 0;
50         tally->min = tally->max = 0;
51 }
52
53 static void tally_add(struct tally *tally, size_t len)
54 {
55         if (tally->num == 0)
56                 tally->max = tally->min = len;
57         else if (len > tally->max)
58                 tally->max = len;
59         else if (len < tally->min)
60                 tally->min = len;
61         tally->num++;
62         tally->total += len;
63 }
64
65 static size_t tally_mean(const struct tally *tally)
66 {
67         if (!tally->num)
68                 return 0;
69         return tally->total / tally->num;
70 }
71
72 static size_t get_hash_length(struct tdb_context *tdb, unsigned int i)
73 {
74         tdb_off_t rec_ptr;
75         size_t count = 0;
76
77         if (tdb_ofs_read(tdb, TDB_HASH_TOP(i), &rec_ptr) == -1)
78                 return 0;
79
80         /* keep looking until we find the right record */
81         while (rec_ptr) {
82                 struct tdb_record r;
83                 ++count;
84                 if (tdb_rec_read(tdb, rec_ptr, &r) == -1)
85                         return 0;
86                 rec_ptr = r.next;
87         }
88         return count;
89 }
90
91 _PUBLIC_ char *tdb_summary(struct tdb_context *tdb)
92 {
93         off_t file_size;
94         tdb_off_t off, rec_off;
95         struct tally freet, keys, data, dead, extra, hashval, uncoal;
96         struct tdb_record rec;
97         char *ret = NULL;
98         bool locked;
99         size_t unc = 0;
100         int len;
101         struct tdb_record recovery;
102
103         /* Read-only databases use no locking at all: it's best-effort.
104          * We may have a write lock already, so skip that case too. */
105         if (tdb->read_only || tdb->allrecord_lock.count != 0) {
106                 locked = false;
107         } else {
108                 if (tdb_lockall_read(tdb) == -1)
109                         return NULL;
110                 locked = true;
111         }
112
113         if (tdb_recovery_area(tdb, tdb->methods, &rec_off, &recovery) != 0) {
114                 goto unlock;
115         }
116
117         tally_init(&freet);
118         tally_init(&keys);
119         tally_init(&data);
120         tally_init(&dead);
121         tally_init(&extra);
122         tally_init(&hashval);
123         tally_init(&uncoal);
124
125         for (off = TDB_DATA_START(tdb->hash_size);
126              off < tdb->map_size - 1;
127              off += sizeof(rec) + rec.rec_len) {
128                 if (tdb->methods->tdb_read(tdb, off, &rec, sizeof(rec),
129                                            DOCONV()) == -1)
130                         goto unlock;
131                 switch (rec.magic) {
132                 case TDB_MAGIC:
133                         tally_add(&keys, rec.key_len);
134                         tally_add(&data, rec.data_len);
135                         tally_add(&extra, rec.rec_len - (rec.key_len
136                                                          + rec.data_len));
137                         if (unc > 1)
138                                 tally_add(&uncoal, unc - 1);
139                         unc = 0;
140                         break;
141                 case TDB_FREE_MAGIC:
142                         tally_add(&freet, rec.rec_len);
143                         unc++;
144                         break;
145                 /* If we crash after ftruncate, we can get zeroes or fill. */
146                 case TDB_RECOVERY_INVALID_MAGIC:
147                 case 0x42424242:
148                         unc++;
149                         /* If it's a valid recovery, we can trust rec_len. */
150                         if (off != rec_off) {
151                                 rec.rec_len = tdb_dead_space(tdb, off)
152                                         - sizeof(rec);
153                         }
154
155                         FALL_THROUGH;
156                 case TDB_DEAD_MAGIC:
157                         tally_add(&dead, rec.rec_len);
158                         break;
159                 default:
160                         TDB_LOG((tdb, TDB_DEBUG_ERROR,
161                                  "Unexpected record magic 0x%x at offset %u\n",
162                                  rec.magic, off));
163                         goto unlock;
164                 }
165         }
166         if (unc > 1)
167                 tally_add(&uncoal, unc - 1);
168
169         for (off = 0; off < tdb->hash_size; off++)
170                 tally_add(&hashval, get_hash_length(tdb, off));
171
172         file_size = tdb->hdr_ofs + tdb->map_size;
173
174         len = asprintf(&ret, SUMMARY_FORMAT,
175                  (unsigned long long)file_size, keys.total+data.total,
176                  (size_t)tdb->hdr_ofs, (size_t)tdb->map_size,
177                  keys.num,
178                  (tdb->hash_fn == tdb_jenkins_hash)?"yes":"no",
179                  (unsigned)tdb->feature_flags, TDB_SUPPORTED_FEATURE_FLAGS,
180                  (tdb->feature_flags & TDB_FEATURE_FLAG_MUTEX)?"yes":"no",
181                  keys.min, tally_mean(&keys), keys.max,
182                  data.min, tally_mean(&data), data.max,
183                  extra.min, tally_mean(&extra), extra.max,
184                  dead.num,
185                  dead.min, tally_mean(&dead), dead.max,
186                  freet.num,
187                  freet.min, tally_mean(&freet), freet.max,
188                  hashval.num,
189                  hashval.min, tally_mean(&hashval), hashval.max,
190                  uncoal.total,
191                  uncoal.min, tally_mean(&uncoal), uncoal.max,
192                  keys.total * 100.0 / file_size,
193                  data.total * 100.0 / file_size,
194                  extra.total * 100.0 / file_size,
195                  freet.total * 100.0 / file_size,
196                  dead.total * 100.0 / file_size,
197                  (keys.num + freet.num + dead.num)
198                  * (sizeof(struct tdb_record) + sizeof(uint32_t))
199                  * 100.0 / file_size,
200                  tdb->hash_size * sizeof(tdb_off_t)
201                  * 100.0 / file_size);
202         if (len == -1) {
203                 goto unlock;
204         }
205
206 unlock:
207         if (locked) {
208                 tdb_unlockall_read(tdb);
209         }
210         return ret;
211 }