PCP: support for 'dynamic columns' added at runtime

Implements support for arbitrary Performance Co-Pilot
metrics with per-process instance domains to form new
htop columns.  The column-to-metric mappings are setup
using configuration files which will be documented via
man pages as part of a follow-up commit.

We provide an initial set of column configurations so
as to provide new capabilities to pcp-htop: including
configs for containers, open fd counts, scheduler run
queue time, tcp/udp bytes/calls sent/recv, delay acct,
virtual machine guests, detailed virtual memory, swap.

Note there is a change to the configuration file path
resolution algorithm introduced for 'dynamic meters'.
First, look in any custom PCP_HTOP_DIR location.  Then
iterate, in priority order, users home directory, then
local sysadmins files in /etc/pcp/htop, then readonly
configuration files below /usr/share/pcp/htop.  This
final location becomes the preferred place for our own
shipped meter and column files.

The Settings file (htoprc) writing code is updated to
not using the numeric identifier for dynamic columns.
The same strategy used for dynamic meters is used here
where we write Dynamic(name) so the name can be setup
once more at start.  Regular (static) columns writing
to htoprc - i.e. numerically indexed - is unchanged.

1 files changed, 58 insertions, 20 deletions

diff --git a/pcp/Platform.c b/pcp/Platform.c
index 4ddf7e68..2854d9bd 100644
--- a/pcp/Platform.c
+++ b/pcp/Platform.c
@@ -2,7 +2,7 @@
 htop - linux/Platform.c
 (C) 2014 Hisham H. Muhammad
 (C) 2020-2021 htop dev team
-(C) 2020-2021 Red Hat, Inc.  All Rights Reserved.
+(C) 2020-2021 Red Hat, Inc.
 Released under the GNU GPLv2, see the COPYING file
 in the source distribution for its full text.
 */
@@ -42,6 +42,7 @@ in the source distribution for its full text.
 #include "linux/PressureStallMeter.h"
 #include "linux/ZramMeter.h"
 #include "linux/ZramStats.h"
+#include "pcp/PCPDynamicColumn.h"
 #include "pcp/PCPDynamicMeter.h"
 #include "pcp/PCPProcess.h"
 #include "pcp/PCPProcessList.h"
@@ -51,19 +52,20 @@ in the source distribution for its full text.
 
 
 typedef struct Platform_ {
-   int context;			/* PMAPI(3) context identifier */
-   unsigned int totalMetrics;	/* total number of all metrics */
-   const char** names;		/* name array indexed by Metric */
-   pmID* pmids;			/* all known metric identifiers */
-   pmID* fetch;			/* enabled identifiers for sampling */
-   pmDesc* descs;		/* metric desc array indexed by Metric */
-   pmResult* result;		/* sample values result indexed by Metric */
-   PCPDynamicMeters meters;	/* dynamic meters via configuration files */
-   struct timeval offset;	/* time offset used in archive mode only */
-   long long btime;		/* boottime in seconds since the epoch */
-   char* release;		/* uname and distro from this context */
-   int pidmax;			/* maximum platform process identifier */
-   int ncpu;			/* maximum processor count configured */
+   int context;               /* PMAPI(3) context identifier */
+   size_t totalMetrics;       /* total number of all metrics */
+   const char** names;        /* name array indexed by Metric */
+   pmID* pmids;               /* all known metric identifiers */
+   pmID* fetch;               /* enabled identifiers for sampling */
+   pmDesc* descs;             /* metric desc array indexed by Metric */
+   pmResult* result;          /* sample values result indexed by Metric */
+   PCPDynamicMeters meters;   /* dynamic meters via configuration files */
+   PCPDynamicColumns columns; /* dynamic columns via configuration files */
+   struct timeval offset;     /* time offset used in archive mode only */
+   long long btime;           /* boottime in seconds since the epoch */
+   char* release;             /* uname and distro from this context */
+   int pidmax;                /* maximum platform process identifier */
+   int ncpu;                  /* maximum processor count configured */
 } Platform;
 
 Platform* pcp;
@@ -251,6 +253,10 @@ const pmDesc* Metric_desc(Metric metric) {
    return &pcp->descs[metric];
 }
 
+int Metric_type(Metric metric) {
+   return pcp->descs[metric].type;
+}
+
 pmAtomValue* Metric_values(Metric metric, pmAtomValue* atom, int count, int type) {
    if (pcp->result == NULL)
       return NULL;
@@ -398,12 +404,12 @@ bool Metric_fetch(struct timeval* timestamp) {
    return true;
 }
 
-int Platform_addMetric(Metric id, const char* name) {
+size_t Platform_addMetric(Metric id, const char* name) {
    unsigned int i = (unsigned int)id;
 
    if (i >= PCP_METRIC_COUNT && i >= pcp->totalMetrics) {
       /* added via configuration files */
-      unsigned int j = pcp->totalMetrics + 1;
+      size_t j = pcp->totalMetrics + 1;
       pcp->fetch = xRealloc(pcp->fetch, j * sizeof(pmID));
       pcp->pmids = xRealloc(pcp->pmids, j * sizeof(pmID));
       pcp->names = xRealloc(pcp->names, j * sizeof(char*));
@@ -465,14 +471,17 @@ void Platform_init(void) {
 
    PCPDynamicMeters_init(&pcp->meters);
 
+   pcp->columns.offset = PCP_METRIC_COUNT + pcp->meters.cursor;
+   PCPDynamicColumns_init(&pcp->columns);
+
    sts = pmLookupName(pcp->totalMetrics, pcp->names, pcp->pmids);
    if (sts < 0) {
       fprintf(stderr, "Error: cannot lookup metric names: %s\n", pmErrStr(sts));
       exit(1);
    }
 
-   for (unsigned int i = 0; i < pcp->totalMetrics; i++) {
-      pcp->fetch[i] = PM_ID_NULL;	/* default is to not sample */
+   for (size_t i = 0; i < pcp->totalMetrics; i++) {
+      pcp->fetch[i] = PM_ID_NULL; /* default is to not sample */
 
       /* expect some metrics to be missing - e.g. PMDA not available */
       if (pcp->pmids[i] == PM_ID_NULL)
@@ -501,11 +510,14 @@ void Platform_init(void) {
    Metric_enable(PCP_UNAME_MACHINE, true);
    Metric_enable(PCP_UNAME_DISTRO, true);
 
+   for (size_t i = pcp->columns.offset; i < pcp->columns.offset + pcp->columns.count; i++)
+      Metric_enable(i, true);
+
    Metric_fetch(NULL);
 
    for (Metric metric = 0; metric < PCP_PROC_PID; metric++)
       Metric_enable(metric, true);
-   Metric_enable(PCP_PID_MAX, false);	/* needed one time only */
+   Metric_enable(PCP_PID_MAX, false); /* needed one time only */
    Metric_enable(PCP_BOOTTIME, false);
    Metric_enable(PCP_UNAME_SYSNAME, false);
    Metric_enable(PCP_UNAME_RELEASE, false);
@@ -627,7 +639,7 @@ static double Platform_setOneCPUValues(Meter* this, pmAtomValue* values) {
 
 double Platform_setCPUValues(Meter* this, int cpu) {
    const PCPProcessList* pl = (const PCPProcessList*) this->pl;
-   if (cpu <= 0)	/* use aggregate values */
+   if (cpu <= 0) /* use aggregate values */
       return Platform_setOneCPUValues(this, pl->cpu);
    return Platform_setOneCPUValues(this, pl->percpu[cpu - 1]);
 }
@@ -924,3 +936,29 @@ void Platform_dynamicMeterDisplay(const Meter* meter, RichString* out) {
    if (this)
       PCPDynamicMeter_display(this, meter, out);
 }
+
+Hashtable* Platform_dynamicColumns(void) {
+   return pcp->columns.table;
+}
+
+const char* Platform_dynamicColumnInit(unsigned int key) {
+   PCPDynamicColumn* this = Hashtable_get(pcp->columns.table, key);
+   if (this) {
+      Metric_enable(this->id, true);
+      if (this->super.caption)
+         return this->super.caption;
+      if (this->super.heading)
+         return this->super.heading;
+      return this->super.name;
+   }
+   return NULL;
+}
+
+bool Platform_dynamicColumnWriteField(const Process* proc, RichString* str, unsigned int key) {
+   PCPDynamicColumn* this = Hashtable_get(pcp->columns.table, key);
+   if (this) {
+      PCPDynamicColumn_writeField(this, proc, str);
+      return true;
+   }
+   return false;
+}