From d349995488a13687171a67efd981e986b3b703e5 Mon Sep 17 00:00:00 2001
From: OBATA Akio <obache@wizdas.com>
Date: Mon, 15 Apr 2019 18:02:32 +0900
Subject: Change and simplify `statvfs` conditions in FileSystemStats

`getfsstat` v.s. `getvfsstat` condition is different than
`statfs` v.s. `statvfs`, so split each condition and simplify.

For `get(v)fsstat` side, changed to check and use `getmntinfo`, because
it is better than `get(v)fsstat` with fixed buffer size, and easier
than improve it with dynamic buffer allocation.

Signed-off-by: OBATA Akio <obache@wizdas.com>
---
 ConfigureChecks.cmake                        | 14 ++++++++++++++
 config.h.cmake                               |  6 ++++++
 ksim/monitors/filesystem/filesystemstats.cpp | 26 ++++++++++++++------------
 3 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/ConfigureChecks.cmake b/ConfigureChecks.cmake
index 1b48407..148884c 100644
--- a/ConfigureChecks.cmake
+++ b/ConfigureChecks.cmake
@@ -155,6 +155,20 @@ if ( BUILD_KSIM )
 
   check_include_file( "sys/loadavg.h"  HAVE_SYS_LOADAVG_H )
   check_function_exists( getloadavg    HAVE_GETLOADAVG )
+  check_function_exists( statfs        HAVE_STATFS )
+  check_function_exists( statvfs       HAVE_STATVFS )
+  check_function_exists( getmntinfo    HAVE_GETMNTINFO )
+  if( HAVE_GETMNTINFO )
+    check_cxx_source_compiles("
+      #include <sys/types.h>
+      #include <sys/statvfs.h>
+      int main(){
+        struct statvfs *mntbufp;
+        int flags;
+        return getmntinfo(&mntbufp, flags);
+      }"
+      GETMNTINFO_USES_STATVFS )
+  endif( HAVE_GETMNTINFO )
 
   check_c_source_compiles(
     "#include <linux/kernel.h>
diff --git a/config.h.cmake b/config.h.cmake
index 52adf87..6676c8b 100644
--- a/config.h.cmake
+++ b/config.h.cmake
@@ -91,6 +91,12 @@
 #cmakedefine HAVE_GETLOADAVG
 #endif // HAVE_GETLOADAVG
 
+#cmakedefine HAVE_STATFS
+#if !defined( HAVE_STATVFS )
+#cmakedefine HAVE_STATVFS
+#endif
+#cmakedefine HAVE_GETMNTINFO
+#cmakedefine GETMNTINFO_USES_STATVFS
 
 // superkaramba
 
diff --git a/ksim/monitors/filesystem/filesystemstats.cpp b/ksim/monitors/filesystem/filesystemstats.cpp
index 1aa156d..f60ce58 100644
--- a/ksim/monitors/filesystem/filesystemstats.cpp
+++ b/ksim/monitors/filesystem/filesystemstats.cpp
@@ -30,7 +30,7 @@
 #include <sys/types.h>
 #include <sys/param.h>
 
-#if defined(HAVE_SYS_STATVFS_H) && !defined(__DragonFly__)
+#if defined(HAVE_SYS_STATVFS_H)
 #include <sys/statvfs.h>
 #elif defined( HAVE_SYS_STATFS_H )
 #include <sys/statfs.h>
@@ -59,12 +59,10 @@
 #include <stdio.h>
 #include <unistd.h>
 
-#if defined(HAVE_STATVFS) && !defined(__DragonFly__)
+#if defined(HAVE_STATVFS)
 typedef struct statvfs ksim_statfs;
-#define ksim_getfsstat getvfsstat
-#elif defined( HAVE_STATFS ) || defined( Q_OS_FREEBSD )
+#elif defined( HAVE_STATFS )
 typedef struct statfs ksim_statfs;
-#define ksim_getfsstat getfsstat
 #else
 typedef struct // fall back for (possibly) non-supported systems
 {
@@ -75,9 +73,9 @@ typedef struct // fall back for (possibly) non-supported systems
 
 int fsystemStats( const char * file, ksim_statfs & stats )
 {
-#if defined(HAVE_STATVFS) && !defined(__DragonFly__)
+#if defined(HAVE_STATVFS)
   return statvfs( file, &stats );
-#elif defined( HAVE_STATFS ) || defined( Q_OS_FREEBSD )
+#elif defined( HAVE_STATFS )
   return statfs( file, &stats );
 #else // fall back for (possibly) non-supported systems
   (void)file;
@@ -135,8 +133,8 @@ ksim_mntent * ksim_getmntent( FILE * file )
 }
 
 #define delete_mntent( x )
-#elif defined( HAVE_SYS_UCRED_H ) || defined( HAVE_SYS_MOUNT_H )
-#define USE_FSSTAT
+#elif defined( HAVE_GETMNTINFO )
+#define USE_MNTINFO
 #else
 #define USE_FAILSAFE
 #endif
@@ -163,10 +161,14 @@ FilesystemStats::List FilesystemStats::readEntries()
   endmntent( fp );
 #endif
 
-#ifdef USE_FSSTAT
-  ksim_statfs sfs[32];
+#ifdef USE_MNTINFO
+# ifdef GETMNTINFO_USES_STATVFS
+  struct statvfs *sfs;
+# else
+  struct statfs *sfs;
+# endif
   int fs_count;
-  if ( ( fs_count = ksim_getfsstat( sfs, sizeof( sfs ), 0 ) ) != -1 )
+  if ( ( fs_count = getmntinfo( &sfs, 0 ) ) != -1 )
   {
     for ( int i = 0; i < fs_count; i++ )
     {
-- 
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