Create new File Descriptor meter

CRT.c

@@ -202,6 +202,8 @@ static int CRT_colorSchemes[LAST_COLORSCHEME][LAST_COLORELEMENT] = {
       [PRESSURE_STALL_THREEHUNDRED] = ColorPair(Cyan, Black),
       [PRESSURE_STALL_SIXTY] = A_BOLD | ColorPair(Cyan, Black),
       [PRESSURE_STALL_TEN] = A_BOLD | ColorPair(White, Black),
+      [FILE_DESCRIPTOR_USED] = ColorPair(Green, Black),
+      [FILE_DESCRIPTOR_MAX] = ColorPair(Red, Black),
       [ZFS_MFU] = ColorPair(Blue, Black),
       [ZFS_MRU] = ColorPair(Yellow, Black),
       [ZFS_ANON] = ColorPair(Magenta, Black),
@@ -309,6 +311,8 @@ static int CRT_colorSchemes[LAST_COLORSCHEME][LAST_COLORELEMENT] = {
       [PRESSURE_STALL_THREEHUNDRED] = A_DIM,
       [PRESSURE_STALL_SIXTY] = A_NORMAL,
       [PRESSURE_STALL_TEN] = A_BOLD,
+      [FILE_DESCRIPTOR_USED] = A_BOLD,
+      [FILE_DESCRIPTOR_MAX] = A_BOLD,
       [ZFS_MFU] = A_NORMAL,
       [ZFS_MRU] = A_NORMAL,
       [ZFS_ANON] = A_DIM,
@@ -416,6 +420,8 @@ static int CRT_colorSchemes[LAST_COLORSCHEME][LAST_COLORELEMENT] = {
       [PRESSURE_STALL_THREEHUNDRED] = ColorPair(Black, White),
       [PRESSURE_STALL_SIXTY] = ColorPair(Black, White),
       [PRESSURE_STALL_TEN] = ColorPair(Black, White),
+      [FILE_DESCRIPTOR_USED] = ColorPair(Green, White),
+      [FILE_DESCRIPTOR_MAX] = ColorPair(Red, White),
       [ZFS_MFU] = ColorPair(Cyan, White),
       [ZFS_MRU] = ColorPair(Yellow, White),
       [ZFS_ANON] = ColorPair(Magenta, White),
@@ -523,6 +529,8 @@ static int CRT_colorSchemes[LAST_COLORSCHEME][LAST_COLORELEMENT] = {
       [PRESSURE_STALL_THREEHUNDRED] = ColorPair(Black, Black),
       [PRESSURE_STALL_SIXTY] = ColorPair(Black, Black),
       [PRESSURE_STALL_TEN] = ColorPair(Black, Black),
+      [FILE_DESCRIPTOR_USED] = ColorPair(Green, Black),
+      [FILE_DESCRIPTOR_MAX] = ColorPair(Red, Black),
       [ZFS_MFU] = ColorPair(Cyan, Black),
       [ZFS_MRU] = ColorPair(Yellow, Black),
       [ZFS_ANON] = A_BOLD | ColorPair(Magenta, Black),
@@ -630,6 +638,8 @@ static int CRT_colorSchemes[LAST_COLORSCHEME][LAST_COLORELEMENT] = {
       [PRESSURE_STALL_THREEHUNDRED] = A_BOLD | ColorPair(Black, Blue),
       [PRESSURE_STALL_SIXTY] = A_NORMAL | ColorPair(White, Blue),
       [PRESSURE_STALL_TEN] = A_BOLD | ColorPair(White, Blue),
+      [FILE_DESCRIPTOR_USED] = A_BOLD | ColorPair(Green, Blue),
+      [FILE_DESCRIPTOR_MAX] = A_BOLD | ColorPair(Red, Blue),
       [ZFS_MFU] = A_BOLD | ColorPair(White, Blue),
       [ZFS_MRU] = A_BOLD | ColorPair(Yellow, Blue),
       [ZFS_ANON] = A_BOLD | ColorPair(Magenta, Blue),
@@ -735,6 +745,8 @@ static int CRT_colorSchemes[LAST_COLORSCHEME][LAST_COLORELEMENT] = {
       [PRESSURE_STALL_THREEHUNDRED] = ColorPair(Green, Black),
       [PRESSURE_STALL_SIXTY] = ColorPair(Green, Black),
       [PRESSURE_STALL_TEN] = A_BOLD | ColorPair(Green, Black),
+      [FILE_DESCRIPTOR_USED] = ColorPair(Green, Black),
+      [FILE_DESCRIPTOR_MAX] = ColorPair(Red, Black),
       [ZFS_MFU] = ColorPair(Blue, Black),
       [ZFS_MRU] = ColorPair(Yellow, Black),
       [ZFS_ANON] = ColorPair(Magenta, Black),

CRT.h

@@ -128,6 +128,8 @@ typedef enum ColorElements_ {
    PRESSURE_STALL_TEN,
    PRESSURE_STALL_SIXTY,
    PRESSURE_STALL_THREEHUNDRED,
+   FILE_DESCRIPTOR_USED,
+   FILE_DESCRIPTOR_MAX,
    ZFS_MFU,
    ZFS_MRU,
    ZFS_ANON,

FileDescriptorMeter.c

@@ -0,0 +1,80 @@
+/*
+htop - FileDescriptorMeter.c
+(C) 2022 htop dev team
+Released under the GNU GPLv2+, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include "FileDescriptorMeter.h"
+
+#include <math.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "CRT.h"
+#include "Meter.h"
+#include "Object.h"
+#include "Platform.h"
+#include "RichString.h"
+#include "XUtils.h"
+
+
+static const int FileDescriptorMeter_attributes[] = {
+   FILE_DESCRIPTOR_USED,
+   FILE_DESCRIPTOR_MAX
+};
+
+static void FileDescriptorMeter_updateValues(Meter* this) {
+   this->values[0] = 0;
+   this->values[1] = 1;
+
+   Platform_getFileDescriptors(&this->values[0], &this->values[1]);
+
+   /* only print bar for first value */
+   this->curItems = 1;
+
+   /* Use maximum value for scaling of bar mode */
+   this->total = this->values[1];
+
+   if (isnan(this->values[0])) {
+      xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "unknown/unknown");
+   } else {
+      xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "%.0lf/%.0lf", this->values[0], this->values[1]);
+   }
+}
+
+static void FileDescriptorMeter_display(const Object* cast, RichString* out) {
+   const Meter* this = (const Meter*)cast;
+   char buffer[50];
+   int len;
+
+   if (isnan(this->values[0])) {
+      RichString_appendAscii(out, CRT_colors[METER_TEXT], "unknown");
+      return;
+   }
+
+   RichString_appendAscii(out, CRT_colors[METER_TEXT], "used: ");
+   len = xSnprintf(buffer, sizeof(buffer), "%.0lf", this->values[0]);
+   RichString_appendnAscii(out, CRT_colors[FILE_DESCRIPTOR_USED], buffer, len);
+
+   RichString_appendAscii(out, CRT_colors[METER_TEXT], " max: ");
+   len = xSnprintf(buffer, sizeof(buffer), "%.0lf", this->values[1]);
+   RichString_appendnAscii(out, CRT_colors[FILE_DESCRIPTOR_MAX], buffer, len);
+}
+
+const MeterClass FileDescriptorMeter_class = {
+   .super = {
+      .extends = Class(Meter),
+      .delete = Meter_delete,
+      .display = FileDescriptorMeter_display,
+   },
+   .updateValues = FileDescriptorMeter_updateValues,
+   .defaultMode = TEXT_METERMODE,
+   .maxItems = 2,
+   .total = 100.0,
+   .attributes = FileDescriptorMeter_attributes,
+   .name = "FileDescriptors",
+   .uiName = "File Descriptors",
+   .caption = "FDs: ",
+   .description = "Number of allocated/available file descriptors"
+};

FileDescriptorMeter.h

@@ -0,0 +1,15 @@
+#ifndef HEADER_FileDescriptorMeter
+#define HEADER_FileDescriptorMeter
+/*
+htop - FileDescriptorMeter.h
+(C) 2022 htop dev team
+Released under the GNU GPLv2+, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include "Meter.h"
+
+
+extern const MeterClass FileDescriptorMeter_class;
+
+#endif

Makefile.am

@@ -152,6 +152,7 @@ myhtopheaders = \
 # -----
 
 linux_platform_headers = \
+	FileDescriptorMeter.h \
 	generic/gettime.h \
 	generic/hostname.h \
 	generic/uname.h \
@@ -174,6 +175,7 @@ linux_platform_headers = \
 	zfs/ZfsCompressedArcMeter.h
 
 linux_platform_sources = \
+	FileDescriptorMeter.c \
 	generic/gettime.c \
 	generic/hostname.c \
 	generic/uname.c \

linux/Platform.c

@@ -29,6 +29,7 @@ in the source distribution for its full text.
 #include "DateMeter.h"
 #include "DateTimeMeter.h"
 #include "DiskIOMeter.h"
+#include "FileDescriptorMeter.h"
 #include "HostnameMeter.h"
 #include "HugePageMeter.h"
 #include "LoadAverageMeter.h"
@@ -247,6 +248,7 @@ const MeterClass* const Platform_meterTypes[] = {
    &NetworkIOMeter_class,
    &SELinuxMeter_class,
    &SystemdMeter_class,
+   &FileDescriptorMeter_class,
    NULL
 };
 
@@ -557,6 +559,24 @@ void Platform_getPressureStall(const char* file, bool some, double* ten, double*
    fclose(fd);
 }
 
+void Platform_getFileDescriptors(double* used, double* max) {
+   *used = NAN;
+   *max = 65536;
+
+   FILE* fd = fopen(PROCDIR "/sys/fs/file-nr", "r");
+   if (!fd)
+      return;
+
+   unsigned long v1, v2, v3;
+   int total = fscanf(fd, "%lu %lu %lu", &v1, &v2, &v3);
+   if (total == 3) {
+      *used = v1;
+      *max = v3;
+   }
+
+   fclose(fd);
+}
+
 bool Platform_getDiskIO(DiskIOData* data) {
    FILE* fd = fopen(PROCDIR "/diskstats", "r");
    if (!fd)

linux/Platform.h

@@ -79,6 +79,8 @@ FileLocks_ProcessData* Platform_getProcessLocks(pid_t pid);
 
 void Platform_getPressureStall(const char* file, bool some, double* ten, double* sixty, double* threehundred);
 
+void Platform_getFileDescriptors(double* used, double* max);
+
 bool Platform_getDiskIO(DiskIOData* data);
 
 bool Platform_getNetworkIO(NetworkIOData* data);