Only initialize and gather delay accounting data if a related column is enabled

Avoid creating and communicating over a netlink socket by default, which
triggers cap_net_admin checks as root.

linux/LinuxProcess.c

@@ -88,9 +88,9 @@ const ProcessFieldData Process_fields[LAST_PROCESSFIELD] = {
    [OOM] = { .name = "OOM", .title = " OOM ", .description = "OOM (Out-of-Memory) killer score", .flags = PROCESS_FLAG_LINUX_OOM, },
    [IO_PRIORITY] = { .name = "IO_PRIORITY", .title = "IO ", .description = "I/O priority", .flags = PROCESS_FLAG_LINUX_IOPRIO, },
 #ifdef HAVE_DELAYACCT
-   [PERCENT_CPU_DELAY] = { .name = "PERCENT_CPU_DELAY", .title = "CPUD% ", .description = "CPU delay %", .flags = 0, },
-   [PERCENT_IO_DELAY] = { .name = "PERCENT_IO_DELAY", .title = "IOD% ", .description = "Block I/O delay %", .flags = 0, },
-   [PERCENT_SWAP_DELAY] = { .name = "PERCENT_SWAP_DELAY", .title = "SWAPD% ", .description = "Swapin delay %", .flags = 0, },
+   [PERCENT_CPU_DELAY] = { .name = "PERCENT_CPU_DELAY", .title = "CPUD% ", .description = "CPU delay %", .flags = PROCESS_FLAG_LINUX_DELAYACCT, },
+   [PERCENT_IO_DELAY] = { .name = "PERCENT_IO_DELAY", .title = "IOD% ", .description = "Block I/O delay %", .flags = PROCESS_FLAG_LINUX_DELAYACCT, },
+   [PERCENT_SWAP_DELAY] = { .name = "PERCENT_SWAP_DELAY", .title = "SWAPD% ", .description = "Swapin delay %", .flags = PROCESS_FLAG_LINUX_DELAYACCT, },
 #endif
    [M_PSS] = { .name = "M_PSS", .title = "  PSS ", .description = "proportional set size, same as M_RESIDENT but each page is divided by the number of processes sharing it.", .flags = PROCESS_FLAG_LINUX_SMAPS, },
    [M_SWAP] = { .name = "M_SWAP", .title = " SWAP ", .description = "Size of the process's swapped pages", .flags = PROCESS_FLAG_LINUX_SMAPS, },

linux/LinuxProcess.h

@@ -18,16 +18,17 @@ in the source distribution for its full text.
 #include "Settings.h"
 
 
-#define PROCESS_FLAG_LINUX_IOPRIO   0x00000100
-#define PROCESS_FLAG_LINUX_OPENVZ   0x00000200
-#define PROCESS_FLAG_LINUX_VSERVER  0x00000400
-#define PROCESS_FLAG_LINUX_CGROUP   0x00000800
-#define PROCESS_FLAG_LINUX_OOM      0x00001000
-#define PROCESS_FLAG_LINUX_SMAPS    0x00002000
-#define PROCESS_FLAG_LINUX_CTXT     0x00004000
-#define PROCESS_FLAG_LINUX_SECATTR  0x00008000
-#define PROCESS_FLAG_LINUX_LRS_FIX  0x00010000
-#define PROCESS_FLAG_LINUX_CWD      0x00020000
+#define PROCESS_FLAG_LINUX_IOPRIO    0x00000100
+#define PROCESS_FLAG_LINUX_OPENVZ    0x00000200
+#define PROCESS_FLAG_LINUX_VSERVER   0x00000400
+#define PROCESS_FLAG_LINUX_CGROUP    0x00000800
+#define PROCESS_FLAG_LINUX_OOM       0x00001000
+#define PROCESS_FLAG_LINUX_SMAPS     0x00002000
+#define PROCESS_FLAG_LINUX_CTXT      0x00004000
+#define PROCESS_FLAG_LINUX_SECATTR   0x00008000
+#define PROCESS_FLAG_LINUX_LRS_FIX   0x00010000
+#define PROCESS_FLAG_LINUX_CWD       0x00020000
+#define PROCESS_FLAG_LINUX_DELAYACCT 0x00040000
 
 
 /* LinuxProcessMergedCommand is populated by LinuxProcess_makeCommandStr: It

linux/LinuxProcessList.c

@@ -208,10 +208,6 @@ ProcessList* ProcessList_new(UsersTable* usersTable, Hashtable* pidMatchList, ui
    ProcessList_init(pl, Class(LinuxProcess), usersTable, pidMatchList, userId);
    LinuxProcessList_initTtyDrivers(this);
 
-   #ifdef HAVE_DELAYACCT
-   LinuxProcessList_initNetlinkSocket(this);
-   #endif
-
    // Initialize page size
    pageSize = sysconf(_SC_PAGESIZE);
    if (pageSize == -1)
@@ -955,12 +951,19 @@ static int handleNetlinkMsg(struct nl_msg* nlmsg, void* linuxProcess) {
 static void LinuxProcessList_readDelayAcctData(LinuxProcessList* this, LinuxProcess* process) {
    struct nl_msg* msg;
 
+   if (!this->netlink_socket) {
+       LinuxProcessList_initNetlinkSocket(this);
+       if (!this->netlink_socket) {
+          goto delayacct_failure;
+       }
+   }
+
    if (nl_socket_modify_cb(this->netlink_socket, NL_CB_VALID, NL_CB_CUSTOM, handleNetlinkMsg, process) < 0) {
-      return;
+      goto delayacct_failure;
    }
 
    if (! (msg = nlmsg_alloc())) {
-      return;
+      goto delayacct_failure;
    }
 
    if (! genlmsg_put(msg, NL_AUTO_PID, NL_AUTO_SEQ, this->netlink_family, 0, NLM_F_REQUEST, TASKSTATS_CMD_GET, TASKSTATS_VERSION)) {
@@ -972,15 +975,19 @@ static void LinuxProcessList_readDelayAcctData(LinuxProcessList* this, LinuxProc
    }
 
    if (nl_send_sync(this->netlink_socket, msg) < 0) {
-      process->swapin_delay_percent = NAN;
-      process->blkio_delay_percent = NAN;
-      process->cpu_delay_percent = NAN;
-      return;
+      goto delayacct_failure;
    }
 
    if (nl_recvmsgs_default(this->netlink_socket) < 0) {
-      return;
+      goto delayacct_failure;
    }
+
+   return;
+
+delayacct_failure:
+   process->swapin_delay_percent = NAN;
+   process->blkio_delay_percent = NAN;
+   process->cpu_delay_percent = NAN;
 }
 
 #endif
@@ -1419,7 +1426,9 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, openat_arg_
       }
 
       #ifdef HAVE_DELAYACCT
-      LinuxProcessList_readDelayAcctData(this, lp);
+      if (settings->flags & PROCESS_FLAG_LINUX_DELAYACCT) {
+         LinuxProcessList_readDelayAcctData(this, lp);
+      }
       #endif
 
       if (settings->flags & PROCESS_FLAG_LINUX_CGROUP) {