Linux: add process->starttime and use it for STARTTIME column (#700)

this way a remount of /proc will not reset starttimes
and we can also see startup times for processes started before the mount
of /proc

also record btime (boot time in seconds since epoch) as Linux semi-global

linux/LinuxProcess.c

@@ -15,6 +15,7 @@ in the source distribution for its full text.
 #include <unistd.h>
 #include <string.h>
 #include <sys/syscall.h>
+#include <time.h>
 
 /*{
 
@@ -106,6 +107,7 @@ typedef struct LinuxProcess_ {
    long m_drs;
    long m_lrs;
    long m_dt;
+   unsigned long long starttime;
    #ifdef HAVE_TASKSTATS
    unsigned long long io_rchar;
    unsigned long long io_wchar;
@@ -152,6 +154,8 @@ typedef struct LinuxProcess_ {
 
 }*/
 
+long long btime; /* semi-global */
+
 ProcessFieldData Process_fields[] = {
    [0] = { .name = "", .title = NULL, .description = NULL, .flags = 0, },
    [PID] = { .name = "PID", .title = "    PID ", .description = "Process/thread ID", .flags = 0, },
@@ -344,6 +348,13 @@ void LinuxProcess_writeField(Process* this, RichString* str, ProcessField field)
    case STIME: Process_printTime(str, lp->stime); return;
    case CUTIME: Process_printTime(str, lp->cutime); return;
    case CSTIME: Process_printTime(str, lp->cstime); return;
+   case STARTTIME: {
+     struct tm date;
+     time_t starttimewall = btime + (lp->starttime / sysconf(_SC_CLK_TCK));
+     (void) localtime_r(&starttimewall, &date);
+     strftime(buffer, n, ((starttimewall > time(NULL) - 86400) ? "%R " : "%b%d "), &date);
+     break;
+   }
    #ifdef HAVE_TASKSTATS
    case RCHAR:  Process_colorNumber(str, lp->io_rchar, coloring); return;
    case WCHAR:  Process_colorNumber(str, lp->io_wchar, coloring); return;
@@ -428,6 +439,12 @@ long LinuxProcess_compare(const void* v1, const void* v2) {
    case CUTIME: diff = p2->cutime - p1->cutime; goto test_diff;
    case STIME:  diff = p2->stime - p1->stime; goto test_diff;
    case CSTIME: diff = p2->cstime - p1->cstime; goto test_diff;
+   case STARTTIME: {
+      if (p1->starttime == p2->starttime)
+         return (p1->super.pid - p2->super.pid);
+      else
+         return (p1->starttime - p2->starttime);
+   }
    #ifdef HAVE_TASKSTATS
    case RCHAR:  diff = p2->io_rchar - p1->io_rchar; goto test_diff;
    case WCHAR:  diff = p2->io_wchar - p1->io_wchar; goto test_diff;

linux/LinuxProcess.h

@@ -98,6 +98,7 @@ typedef struct LinuxProcess_ {
    long m_drs;
    long m_lrs;
    long m_dt;
+   unsigned long long starttime;
    #ifdef HAVE_TASKSTATS
    unsigned long long io_rchar;
    unsigned long long io_wchar;
@@ -143,6 +144,8 @@ typedef struct LinuxProcess_ {
 #endif
 
 
+long long btime; /* semi-global */
+
 extern ProcessFieldData Process_fields[];
 
 extern ProcessPidColumn Process_pidColumns[];

linux/LinuxProcessList.c

@@ -47,6 +47,8 @@ in the source distribution for its full text.
 
 #include "ProcessList.h"
 
+extern long long btime;
+
 typedef struct CPUData_ {
    unsigned long long int totalTime;
    unsigned long long int userTime;
@@ -111,7 +113,7 @@ typedef struct LinuxProcessList_ {
 #endif
 
 #ifndef PROC_LINE_LENGTH
-#define PROC_LINE_LENGTH 512
+#define PROC_LINE_LENGTH 4096
 #endif
 
 }*/
@@ -230,8 +232,8 @@ static void LinuxProcessList_initNetlinkSocket(LinuxProcessList* this) {
 ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* pidWhiteList, uid_t userId) {
    LinuxProcessList* this = xCalloc(1, sizeof(LinuxProcessList));
    ProcessList* pl = &(this->super);
+
    ProcessList_init(pl, Class(LinuxProcess), usersTable, pidWhiteList, userId);
-   
    LinuxProcessList_initTtyDrivers(this);
 
    #ifdef HAVE_DELAYACCT
@@ -243,13 +245,19 @@ ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* pidWhiteList, ui
    if (file == NULL) {
       CRT_fatalError("Cannot open " PROCSTATFILE);
    }
-   char buffer[PROC_LINE_LENGTH + 1];
    int cpus = -1;
    do {
-      cpus++;
-      char * s = fgets(buffer, PROC_LINE_LENGTH, file);
-      (void) s;
-   } while (String_startsWith(buffer, "cpu"));
+      char buffer[PROC_LINE_LENGTH + 1];
+      if (fgets(buffer, PROC_LINE_LENGTH + 1, file) == NULL) {
+         CRT_fatalError("No btime in " PROCSTATFILE);
+      } else if (String_startsWith(buffer, "cpu")) {
+         cpus++;
+      } else if (String_startsWith(buffer, "btime ")) {
+         sscanf(buffer, "btime %lld\n", &btime);
+         break;
+      }
+   } while(true);
+
    fclose(file);
 
    pl->cpuCount = MAX(cpus - 1, 1);
@@ -259,7 +267,6 @@ ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* pidWhiteList, ui
       this->cpus[i].totalTime = 1;
       this->cpus[i].totalPeriod = 1;
    }
-
    return pl;
 }
 
@@ -355,7 +362,10 @@ static bool LinuxProcessList_readStatFile(Process *process, const char* dirname,
    location += 1;
    process->nlwp = strtol(location, &location, 10);
    location += 1;
-   for (int i=0; i<17; i++) location = strchr(location, ' ')+1;
+   location = strchr(location, ' ')+1;
+   lp->starttime = strtoll(location, &location, 10);
+   location += 1;
+   for (int i=0; i<15; i++) location = strchr(location, ' ')+1;
    process->exit_signal = strtol(location, &location, 10);
    location += 1;
    assert(location != NULL);
@@ -377,13 +387,6 @@ static bool LinuxProcessList_statProcessDir(Process* process, const char* dirnam
    if (statok == -1)
       return false;
    process->st_uid = sstat.st_uid;
-  
-   struct tm date;
-   time_t ctime = sstat.st_ctime;
-   process->starttime_ctime = ctime;
-   (void) localtime_r((time_t*) &ctime, &date);
-   strftime(process->starttime_show, 7, ((ctime > curTime - 86400) ? "%R " : "%b%d "), &date);
-   
    return true;
 }
 

linux/LinuxProcessList.h

@@ -20,6 +20,8 @@ in the source distribution for its full text.
 
 #include "ProcessList.h"
 
+extern long long btime;
+
 typedef struct CPUData_ {
    unsigned long long int totalTime;
    unsigned long long int userTime;
@@ -84,7 +86,7 @@ typedef struct LinuxProcessList_ {
 #endif
 
 #ifndef PROC_LINE_LENGTH
-#define PROC_LINE_LENGTH 512
+#define PROC_LINE_LENGTH 4096
 #endif