1 /*
2 Copyright (c) 2017, MariaDB
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; version 2 of the License.
7
8 This program is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 GNU General Public License for more details.
12
13 You should have received a copy of the GNU General Public License
14 along with this program; if not, write to the Free Software
15 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
16
17 #include <my_global.h>
18 #include <sys/statvfs.h>
19 #include <sys/types.h>
20 #include <mntent.h>
21 #include <sql_class.h>
22 #include <table.h>
23 #include <sql_acl.h> /* check_global_access() */
24
25 bool schema_table_store_record(THD *thd, TABLE *table);
26
27 namespace
28 {
29
30 struct st_mysql_information_schema disks_table_info = { MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION };
31
32 ST_FIELD_INFO disks_table_fields[]=
33 {
34 { "Disk", PATH_MAX, MYSQL_TYPE_STRING, 0, 0 ,0, 0 },
35 { "Path", PATH_MAX, MYSQL_TYPE_STRING, 0, 0 ,0, 0 },
36 { "Total", 32, MYSQL_TYPE_LONGLONG, 0, 0 ,0 ,0 }, // Total amount available
37 { "Used", 32, MYSQL_TYPE_LONGLONG, 0, 0 ,0 ,0 }, // Amount of space used
38 { "Available", 32, MYSQL_TYPE_LONGLONG, 0, 0 ,0 ,0 }, // Amount available to users other than root.
39 { 0, 0, MYSQL_TYPE_NULL, 0, 0, 0, 0 }
40 };
41
disks_table_add_row(THD * pThd,TABLE * pTable,const char * zDisk,const char * zPath,const struct statvfs & info)42 int disks_table_add_row(THD* pThd,
43 TABLE* pTable,
44 const char* zDisk,
45 const char* zPath,
46 const struct statvfs& info)
47 {
48 // From: http://pubs.opengroup.org/onlinepubs/009695399/basedefs/sys/statvfs.h.html
49 //
50 // f_frsize Fundamental file system block size.
51 // f_blocks Total number of blocks on file system in units of f_frsize.
52 // f_bfree Total number of free blocks.
53 // f_bavail Number of free blocks available to non-privileged process.
54
55 ulonglong total = ((ulonglong)info.f_frsize * info.f_blocks) / 1024;
56 ulonglong used = ((ulonglong)info.f_frsize *
57 (info.f_blocks - info.f_bfree)) / 1024;
58 ulonglong avail = ((ulonglong)info.f_frsize * info.f_bavail) / 1024;
59
60 pTable->field[0]->store(zDisk, strlen(zDisk), system_charset_info);
61 pTable->field[1]->store(zPath, strlen(zPath), system_charset_info);
62 pTable->field[2]->store(total);
63 pTable->field[3]->store(used);
64 pTable->field[4]->store(avail);
65
66 // 0 means success.
67 return (schema_table_store_record(pThd, pTable) != 0) ? 1 : 0;
68 }
69
disks_table_add_row(THD * pThd,TABLE * pTable,const char * zDisk,const char * zPath)70 int disks_table_add_row(THD* pThd, TABLE* pTable, const char* zDisk, const char* zPath)
71 {
72 int rv = 0;
73
74 struct statvfs info;
75
76 if (statvfs(zPath, &info) == 0) // We ignore failures.
77 {
78 rv = disks_table_add_row(pThd, pTable, zDisk, zPath, info);
79 }
80
81 return rv;
82 }
83
disks_fill_table(THD * pThd,TABLE_LIST * pTables,Item * pCond)84 int disks_fill_table(THD* pThd, TABLE_LIST* pTables, Item* pCond)
85 {
86 int rv = 1;
87 TABLE* pTable = pTables->table;
88
89 if (check_global_access(pThd, FILE_ACL, true))
90 return 0;
91
92 FILE* pFile = setmntent("/etc/mtab", "r");
93
94 if (pFile)
95 {
96 const size_t BUFFER_SIZE = 4096; // 4K should be sufficient.
97
98 char* pBuffer = new (std::nothrow) char [BUFFER_SIZE];
99
100 if (pBuffer)
101 {
102 rv = 0;
103
104 struct mntent ent;
105 struct mntent* pEnt;
106
107 while ((rv == 0) && (pEnt = getmntent_r(pFile, &ent, pBuffer, BUFFER_SIZE)))
108 {
109 // We only report the ones that refer to physical disks.
110 if (pEnt->mnt_fsname[0] == '/')
111 {
112 rv = disks_table_add_row(pThd, pTable, pEnt->mnt_fsname, pEnt->mnt_dir);
113 }
114 }
115
116 delete [] pBuffer;
117 }
118 else
119 {
120 rv = 1;
121 }
122
123 endmntent(pFile);
124 }
125
126 return rv;
127 }
128
disks_table_init(void * ptr)129 int disks_table_init(void *ptr)
130 {
131 ST_SCHEMA_TABLE* pSchema_table = (ST_SCHEMA_TABLE*)ptr;
132
133 pSchema_table->fields_info = disks_table_fields;
134 pSchema_table->fill_table = disks_fill_table;
135 return 0;
136 }
137
138 }
139
140 extern "C"
141 {
142
maria_declare_plugin(disks)143 maria_declare_plugin(disks)
144 {
145 MYSQL_INFORMATION_SCHEMA_PLUGIN,
146 &disks_table_info, /* type-specific descriptor */
147 "DISKS", /* table name */
148 "Johan Wikman", /* author */
149 "Disk space information", /* description */
150 PLUGIN_LICENSE_GPL, /* license type */
151 disks_table_init, /* init function */
152 NULL, /* deinit function */
153 0x0101, /* version = 1.1 */
154 NULL, /* no status variables */
155 NULL, /* no system variables */
156 "1.1", /* String version representation */
157 MariaDB_PLUGIN_MATURITY_STABLE /* Maturity (see include/mysql/plugin.h)*/
158 }
159 mysql_declare_plugin_end;
160
161 }
162