Commit 129616c7 authored by Daniel Black's avatar Daniel Black

MDEV-28592 disks plugin - getmntinfo (BSD) & getmntent (AIX)

Thanks to references from Brad Smith, BSDs use getmntinfo as
a system call for mounted filesystems.

Most BSDs return statfs structures, (and we use OSX's statfs64),
but NetBSD uses a statvfs structure.

Simplify Linux getmntent_r to just use getmntent.

AIX uses getmntent.

An attempt at writing Solaris compatibility with
a small bit of HPUX compatibility was made based on man page
entries only. Fixes welcome.

statvfs structures now use f_bsize for consistency with statfs

Test case adjusted as PATH_MAX is OS defined (e.g. 1023 on AIX)

Fixes: 0ee5cf83

also fixes:

MDEV-27818: Disk plugin does not show zpool mounted devices

This is because zpool mounted point don't begin with /.

Due to the proliferation of multiple filesystem types since this
was written, we restrict the entries listed in the disks plugin
to excude:
* read only mount points (no point monitoring, and
  includes squash, snaps, sysfs, procfs, cgroups...)
* mount points that aren't directories (excludes /etc/hostname and
  similar mounts in containers). (getmntent (Linux/AIX) only)
* exclude systems where there is no capacity listed (excludes various
  virtual filesystem types).

Reviewer: Sergei Golubchik
parent 57739ae9
......@@ -64,6 +64,10 @@ SET(HAVE_GETHOSTBYADDR_R CACHE INTERNAL "")
SET(HAVE_GETHRTIME CACHE INTERNAL "")
SET(HAVE_GETPAGESIZE CACHE INTERNAL "")
SET(HAVE_GETPASS CACHE INTERNAL "")
SET(HAVE_GETMNTENT CACHE INTERNAL "")
SET(HAVE_GETMNTENT_IN_SYS_MNTAB CACHE INTERNAL "")
SET(HAVE_GETMNTINFO CACHE INTERNAL "")
SET(HAVE_GETMNTINFO64 CACHE INTERNAL "")
SET(HAVE_GETPASSPHRASE CACHE INTERNAL "")
SET(HAVE_GETPWNAM CACHE INTERNAL "")
SET(HAVE_GETPWUID CACHE INTERNAL "")
......@@ -146,6 +150,7 @@ SET(HAVE_SELECT 1 CACHE INTERNAL "")
SET(HAVE_SELECT_H CACHE INTERNAL "")
SET(HAVE_SETENV CACHE INTERNAL "")
SET(HAVE_SETLOCALE 1 CACHE INTERNAL "")
SET(HAVE_SETMNTENT CACHE INTERNAL "")
SET(HAVE_SIGACTION CACHE INTERNAL "")
SET(HAVE_SIGINT 1 CACHE INTERNAL "")
SET(HAVE_SIGPIPE CACHE INTERNAL "")
......
......@@ -35,6 +35,11 @@
#cmakedefine HAVE_FLOAT_H 1
#cmakedefine HAVE_FNMATCH_H 1
#cmakedefine HAVE_FPU_CONTROL_H 1
#cmakedefine HAVE_GETMNTENT 1
#cmakedefine HAVE_GETMNTENT_IN_SYS_MNTAB 1
#cmakedefine HAVE_GETMNTINFO 1
#cmakedefine HAVE_GETMNTINFO64 1
#cmakedefine HAVE_GETMNTINFO_TAKES_statvfs 1
#cmakedefine HAVE_GRP_H 1
#cmakedefine HAVE_IA64INTRIN_H 1
#cmakedefine HAVE_IEEEFP_H 1
......@@ -214,6 +219,7 @@
#cmakedefine HAVE_SELECT 1
#cmakedefine HAVE_SETENV 1
#cmakedefine HAVE_SETLOCALE 1
#cmakedefine HAVE_SETMNTENT 1
#cmakedefine HAVE_SETUPTERM 1
#cmakedefine HAVE_SIGSET 1
#cmakedefine HAVE_SIGACTION 1
......
INCLUDE (CheckIncludeFiles)
CHECK_INCLUDE_FILES ("sys/statvfs.h;mntent.h" INFO_HEADERS LANGUAGE CXX)
IF (INFO_HEADERS)
CHECK_SYMBOL_EXISTS (getmntent "mntent.h" HAVE_GETMNTENT)
CHECK_SYMBOL_EXISTS (getmntent "sys/mnttab.h" HAVE_GETMNTENT_IN_SYS_MNTAB)
CHECK_SYMBOL_EXISTS (setmntent "mntent.h" HAVE_SETMNTENT)
CHECK_SYMBOL_EXISTS (getmntinfo "sys/types.h;sys/mount.h" HAVE_GETMNTINFO)
CHECK_SYMBOL_EXISTS (getmntinfo64 "sys/types.h;sys/mount.h" HAVE_GETMNTINFO64)
IF (HAVE_GETMNTINFO)
CHECK_CXX_SOURCE_COMPILES("
#include <sys/types.h>
#include <sys/statvfs.h>
int main()
{
struct statvfs *s;
return getmntinfo(&s, ST_WAIT);
}
" HAVE_GETMNTINFO_TAKES_statvfs)
ENDIF()
IF (HAVE_GETMNTENT OR HAVE_GETMNTENT_IN_SYS_MNTAB OR
HAVE_GETMNTINFO OR HAVE_GETMNTINFO64)
INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/sql)
MYSQL_ADD_PLUGIN(DISKS information_schema_disks.cc MODULE_ONLY RECOMPILE_FOR_EMBEDDED)
ENDIF()
......@@ -17,11 +17,45 @@
#include <my_global.h>
#include <sys/statvfs.h>
#include <sys/types.h>
#if defined(HAVE_GETMNTENT)
#include <mntent.h>
#elif !defined(HAVE_GETMNTINFO_TAKES_statvfs)
/* getmntinfo (the not NetBSD variants) */
#include <sys/param.h>
#include <sys/ucred.h>
#include <sys/mount.h>
#endif
#if defined(HAVE_GETMNTENT_IN_SYS_MNTAB)
#include <sys/mnttab.h>
#define HAVE_GETMNTENT
#endif
#include <sql_class.h>
#include <table.h>
#include <sql_acl.h> /* check_global_access() */
/*
This intends to support *BSD's, macOS, Solaris, AIX, HP-UX, and Linux.
specificly:
FreeBSD/OpenBSD/DragonFly (statfs) NetBSD (statvfs) uses getmntinfo().
macOS uses getmntinfo64().
Linux can use getmntent_r(), but we've just used getmntent for simplification.
Linux/Solaris/AIX/HP-UX uses setmntent()/getmntent().
Solaris uses getmntent() with a diffent prototype, return structure, and
no setmntent(fopen instead)
*/
#if defined(HAVE_GETMNTINFO_TAKES_statvfs) || defined(HAVE_GETMNTENT)
typedef struct statvfs st_info;
#elif defined(HAVE_GETMNTINFO64)
typedef struct statfs64 st_info;
#else // GETMNTINFO
typedef struct statfs st_info;
#endif
#ifndef MOUNTED
/* HPUX - https://docstore.mik.ua/manuals/hp-ux/en/B2355-60130/getmntent.3X.html */
#define MOUNTED MNT_MNTTAB
#endif
bool schema_table_store_record(THD *thd, TABLE *table);
namespace
......@@ -39,23 +73,40 @@ ST_FIELD_INFO disks_table_fields[]=
{ 0, 0, MYSQL_TYPE_NULL, 0, 0, 0, 0 }
};
int disks_table_add_row(THD* pThd,
TABLE* pTable,
const char* zDisk,
const char* zPath,
const struct statvfs& info)
static int disks_table_add_row_stat(
THD* pThd,
TABLE* pTable,
const char* zDisk,
const char* zPath,
const st_info &info)
{
// From: http://pubs.opengroup.org/onlinepubs/009695399/basedefs/sys/statvfs.h.html
// and same for statfs:
// From: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/statfs.2.html#//apple_ref/doc/man/2/statfs
// and: https://www.freebsd.org/cgi/man.cgi?query=statfs&sektion=2&apropos=0&manpath=FreeBSD+13.1-RELEASE+and+Ports
//
// f_frsize Fundamental file system block size.
// f_bsize Fundamental file system block size.
// f_blocks Total number of blocks on file system in units of f_frsize.
// f_bfree Total number of free blocks.
// f_bavail Number of free blocks available to non-privileged process.
ulong block_size= (ulong) info.f_bsize;
ulonglong total = ((ulonglong)info.f_frsize * info.f_blocks) / 1024;
ulonglong used = ((ulonglong)info.f_frsize *
ulonglong total = ((ulonglong) block_size * info.f_blocks) / 1024;
ulonglong used = ((ulonglong) block_size *
(info.f_blocks - info.f_bfree)) / 1024;
ulonglong avail = ((ulonglong)info.f_frsize * info.f_bavail) / 1024;
ulonglong avail = ((ulonglong) block_size * info.f_bavail) / 1024;
/* skip filesystems that don't have any space */
if (!info.f_blocks)
return 0;
/* skip RO mounted filesystems */
#if defined(HAVE_GETMNTINFO_TAKES_statvfs) || defined(HAVE_GETMNTENT)
if (info.f_flag & ST_RDONLY)
#else
if (info.f_flags & MNT_RDONLY)
#endif
return 0;
pTable->field[0]->store(zDisk, strlen(zDisk), system_charset_info);
pTable->field[1]->store(zPath, strlen(zPath), system_charset_info);
......@@ -67,71 +118,147 @@ int disks_table_add_row(THD* pThd,
return (schema_table_store_record(pThd, pTable) != 0) ? 1 : 0;
}
int disks_table_add_row(THD* pThd, TABLE* pTable, const char* zDisk, const char* zPath)
#ifdef HAVE_GETMNTENT
static int disks_table_add_row(THD* pThd, TABLE* pTable, const char* zDisk, const char* zPath)
{
int rv = 0;
struct statvfs info;
st_info info;
if (statvfs(zPath, &info) == 0) // We ignore failures.
{
rv = disks_table_add_row(pThd, pTable, zDisk, zPath, info);
rv = disks_table_add_row_stat(pThd, pTable, zDisk, zPath, info);
}
return rv;
}
#endif
int disks_fill_table(THD* pThd, TABLE_LIST* pTables, Item* pCond)
#ifdef HAVE_GETMNTINFO
static int disks_fill_table(THD* pThd, TABLE_LIST* pTables, Item* pCond)
{
int rv = 1;
TABLE* pTable = pTables->table;
st_info *s;
int count, rv= 0;
TABLE* pTable= pTables->table;
if (check_global_access(pThd, FILE_ACL, true))
return 0;
return 0;
#if defined(HAVE_GETMNTINFO_TAKES_statvfs)
count= getmntinfo(&s, ST_WAIT);
#elif defined(HAVE_GETMNTINFO64)
count= getmntinfo64(&s, MNT_WAIT);
#else
count= getmntinfo(&s, MNT_WAIT);
#endif
if (count == 0)
return 1;
while (count && rv == 0)
{
rv= disks_table_add_row_stat(pThd, pTable, s->f_mntfromname, s->f_mntonname, *s);
count--;
s++;
}
return rv;
}
#else /* HAVE_GETMNTINFO */
static mysql_mutex_t m_getmntent;
FILE* pFile = setmntent("/etc/mtab", "r");
/* HAVE_GETMNTENT */
static int disks_fill_table(THD* pThd, TABLE_LIST* pTables, Item* pCond)
{
int rv= 1;
#ifdef HAVE_SETMNTENT
struct mntent* pEnt;
#else
struct mnttab mnttabent, *pEnt= &mnttabent;
#endif
FILE* pFile;
TABLE* pTable= pTables->table;
if (pFile)
if (check_global_access(pThd, FILE_ACL, true))
return 0;
#ifdef HAVE_SETMNTENT
pFile= setmntent(MOUNTED, "r");
#else
/* Solaris */
pFile= fopen("/etc/mnttab", "r");
#endif
if (!pFile)
return 1;
rv= 0;
/*
We lock the outer loop rather than between getmntent so the multiple
infomation_schema.disks reads don't all start blocking each other and
no-one gets any answers.
*/
mysql_mutex_lock(&m_getmntent);
while ((rv == 0) &&
#if defined(HAVE_SETMNTENT)
(pEnt = getmntent(pFile))
#else
getmntent(pFile, pEnt) != 0
#endif
)
{
const size_t BUFFER_SIZE = 4096; // 4K should be sufficient.
char* pBuffer = new (std::nothrow) char [BUFFER_SIZE];
if (pBuffer)
{
rv = 0;
struct mntent ent;
struct mntent* pEnt;
while ((rv == 0) && (pEnt = getmntent_r(pFile, &ent, pBuffer, BUFFER_SIZE)))
{
// We only report the ones that refer to physical disks.
if (pEnt->mnt_fsname[0] == '/')
{
rv = disks_table_add_row(pThd, pTable, pEnt->mnt_fsname, pEnt->mnt_dir);
}
}
delete [] pBuffer;
}
else
{
rv = 1;
}
endmntent(pFile);
struct stat f;
const char *path, *point;
#ifdef HAVE_SETMNTENT
path= pEnt->mnt_dir;
point= pEnt->mnt_fsname;
#else
path= pEnt->mnt_mountp;
point= pEnt->mnt_special;
#endif
// Try to keep to real storage by excluding
// read only mounts, and mount points that aren't directories
if (hasmntopt(pEnt, MNTOPT_RO) != NULL)
continue;
if (stat(path, &f))
continue;
if (!S_ISDIR(f.st_mode))
continue;
rv= disks_table_add_row(pThd, pTable, point, path);
}
mysql_mutex_unlock(&m_getmntent);
#ifdef HAVE_SETMNTENT
endmntent(pFile);
#else
fclose(pFile);
#endif
return rv;
}
#endif /* HAVE_GETMNTINFO */
int disks_table_init(void *ptr)
static int disks_table_init(void *ptr)
{
ST_SCHEMA_TABLE* pSchema_table = (ST_SCHEMA_TABLE*)ptr;
pSchema_table->fields_info = disks_table_fields;
pSchema_table->fill_table = disks_fill_table;
#ifndef HAVE_GETMNTINFO
mysql_mutex_init(0, &m_getmntent, MY_MUTEX_INIT_SLOW);
#endif
return 0;
}
static int disks_table_deinit(void *ptr __attribute__((unused)))
{
#ifndef HAVE_GETMNTINFO
mysql_mutex_destroy(&m_getmntent);
#endif
return 0;
}
......@@ -145,15 +272,15 @@ maria_declare_plugin(disks)
MYSQL_INFORMATION_SCHEMA_PLUGIN,
&disks_table_info, /* type-specific descriptor */
"DISKS", /* table name */
"Johan Wikman", /* author */
"Johan Wikman, Daniel Black", /* author */
"Disk space information", /* description */
PLUGIN_LICENSE_GPL, /* license type */
disks_table_init, /* init function */
NULL, /* deinit function */
0x0101, /* version = 1.1 */
disks_table_deinit, /* deinit function */
0x0102, /* version = 1.2 */
NULL, /* no status variables */
NULL, /* no system variables */
"1.1", /* String version representation */
"1.2", /* String version representation */
MariaDB_PLUGIN_MATURITY_STABLE /* Maturity (see include/mysql/plugin.h)*/
}
mysql_declare_plugin_end;
......
show create table information_schema.disks;
Table Create Table
DISKS CREATE TEMPORARY TABLE `DISKS` (
`Disk` varchar(4096) NOT NULL,
`Path` varchar(4096) NOT NULL,
`Disk` varchar(pathlen) NOT NULL,
`Path` varchar(pathlen) NOT NULL,
`Total` bigint(32) NOT NULL,
`Used` bigint(32) NOT NULL,
`Available` bigint(32) NOT NULL
......
--replace_regex /varchar\([0-9]+\)/varchar(pathlen)/
show create table information_schema.disks;
select sum(Total) > sum(Available), sum(Total)>sum(Used) from information_schema.disks;
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