1 /*
2 Copyright (c) 2017, 2019, 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 <sql_i_s.h>
23 #include <sql_acl.h> /* check_global_access() */
24
25 bool schema_table_store_record(THD *thd, TABLE *table);
26
27
28 struct st_mysql_information_schema disks_table_info = { MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION };
29
30
31 namespace Show {
32
33 ST_FIELD_INFO disks_table_fields[]=
34 {
35 Column("Disk", Varchar(PATH_MAX), NOT_NULL),
36 Column("Path", Varchar(PATH_MAX), NOT_NULL),
37 Column("Total", SLonglong(32), NOT_NULL), // Total amount available
38 Column("Used", SLonglong(32), NOT_NULL), // Amount of space used
39 Column("Available", SLonglong(32), NOT_NULL), // Amount available to users other than root.
40 CEnd()
41 };
42
43
44
disks_table_add_row(THD * pThd,TABLE * pTable,const char * zDisk,const char * zPath,const struct statvfs & info)45 int disks_table_add_row(THD* pThd,
46 TABLE* pTable,
47 const char* zDisk,
48 const char* zPath,
49 const struct statvfs& info)
50 {
51 // From: http://pubs.opengroup.org/onlinepubs/009695399/basedefs/sys/statvfs.h.html
52 //
53 // f_frsize Fundamental file system block size.
54 // f_blocks Total number of blocks on file system in units of f_frsize.
55 // f_bfree Total number of free blocks.
56 // f_bavail Number of free blocks available to non-privileged process.
57
58 ulonglong total = ((ulonglong)info.f_frsize * info.f_blocks) / 1024;
59 ulonglong used = ((ulonglong)info.f_frsize *
60 (info.f_blocks - info.f_bfree)) / 1024;
61 ulonglong avail = ((ulonglong)info.f_frsize * info.f_bavail) / 1024;
62
63 pTable->field[0]->store(zDisk, strlen(zDisk), system_charset_info);
64 pTable->field[1]->store(zPath, strlen(zPath), system_charset_info);
65 pTable->field[2]->store(total);
66 pTable->field[3]->store(used);
67 pTable->field[4]->store(avail);
68
69 // 0 means success.
70 return (schema_table_store_record(pThd, pTable) != 0) ? 1 : 0;
71 }
72
disks_table_add_row(THD * pThd,TABLE * pTable,const char * zDisk,const char * zPath)73 int disks_table_add_row(THD* pThd, TABLE* pTable, const char* zDisk, const char* zPath)
74 {
75 int rv = 0;
76
77 struct statvfs info;
78
79 if (statvfs(zPath, &info) == 0) // We ignore failures.
80 {
81 rv = disks_table_add_row(pThd, pTable, zDisk, zPath, info);
82 }
83
84 return rv;
85 }
86
disks_fill_table(THD * pThd,TABLE_LIST * pTables,Item * pCond)87 int disks_fill_table(THD* pThd, TABLE_LIST* pTables, Item* pCond)
88 {
89 int rv = 1;
90 TABLE* pTable = pTables->table;
91
92 if (check_global_access(pThd, FILE_ACL, true))
93 return 0;
94
95 FILE* pFile = setmntent("/etc/mtab", "r");
96
97 if (pFile)
98 {
99 const size_t BUFFER_SIZE = 4096; // 4K should be sufficient.
100
101 char* pBuffer = new (std::nothrow) char [BUFFER_SIZE];
102
103 if (pBuffer)
104 {
105 rv = 0;
106
107 struct mntent ent;
108 struct mntent* pEnt;
109
110 while ((rv == 0) && (pEnt = getmntent_r(pFile, &ent, pBuffer, BUFFER_SIZE)))
111 {
112 // We only report the ones that refer to physical disks.
113 if (pEnt->mnt_fsname[0] == '/')
114 {
115 rv = disks_table_add_row(pThd, pTable, pEnt->mnt_fsname, pEnt->mnt_dir);
116 }
117 }
118
119 delete [] pBuffer;
120 }
121 else
122 {
123 rv = 1;
124 }
125
126 endmntent(pFile);
127 }
128
129 return rv;
130 }
131
disks_table_init(void * ptr)132 int disks_table_init(void *ptr)
133 {
134 ST_SCHEMA_TABLE* pSchema_table = (ST_SCHEMA_TABLE*)ptr;
135
136 pSchema_table->fields_info = disks_table_fields;
137 pSchema_table->fill_table = disks_fill_table;
138 return 0;
139 }
140
141 } // namespace Show
142
143 extern "C"
144 {
145
maria_declare_plugin(disks)146 maria_declare_plugin(disks)
147 {
148 MYSQL_INFORMATION_SCHEMA_PLUGIN,
149 &disks_table_info, /* type-specific descriptor */
150 "DISKS", /* table name */
151 "Johan Wikman", /* author */
152 "Disk space information", /* description */
153 PLUGIN_LICENSE_GPL, /* license type */
154 Show::disks_table_init, /* init function */
155 NULL, /* deinit function */
156 0x0101, /* version = 1.1 */
157 NULL, /* no status variables */
158 NULL, /* no system variables */
159 "1.1", /* String version representation */
160 MariaDB_PLUGIN_MATURITY_STABLE /* Maturity (see include/mysql/plugin.h)*/
161 }
162 mysql_declare_plugin_end;
163
164 }
165