linux: move libnl code into separate file

Move all the code using libnl functionality into a separate file to ease
modifications.

No functional change.

1 files changed, 123 insertions, 0 deletions

diff --git a/linux/LibNl.c b/linux/LibNl.c
new file mode 100644
index 00000000..e61b14f6
--- /dev/null
+++ b/linux/LibNl.c
@@ -0,0 +1,123 @@
+/*
+htop - linux/LibNl.c
+(C) 2024 htop dev team
+Released under the GNU GPLv2+, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include "config.h" // IWYU pragma: keep
+
+#ifndef HAVE_DELAYACCT
+#error Compiling this file requires HAVE_DELAYACCT
+#endif
+
+#include "linux/LibNl.h"
+
+#include <linux/netlink.h>
+#include <linux/taskstats.h>
+
+#include <netlink/attr.h>
+#include <netlink/handlers.h>
+#include <netlink/msg.h>
+#include <netlink/netlink.h>
+#include <netlink/socket.h>
+#include <netlink/genl/genl.h>
+#include <netlink/genl/ctrl.h>
+
+
+static void initNetlinkSocket(LinuxProcessTable* this) {
+   this->netlink_socket = nl_socket_alloc();
+   if (this->netlink_socket == NULL) {
+      return;
+   }
+   if (nl_connect(this->netlink_socket, NETLINK_GENERIC) < 0) {
+      return;
+   }
+   this->netlink_family = genl_ctrl_resolve(this->netlink_socket, TASKSTATS_GENL_NAME);
+}
+
+void LibNl_destroyNetlinkSocket(LinuxProcessTable* this) {
+   if (!this->netlink_socket)
+      return;
+
+   nl_close(this->netlink_socket);
+   nl_socket_free(this->netlink_socket);
+   this->netlink_socket = NULL;
+}
+
+static int handleNetlinkMsg(struct nl_msg* nlmsg, void* linuxProcess) {
+   struct nlmsghdr* nlhdr;
+   struct nlattr* nlattrs[TASKSTATS_TYPE_MAX + 1];
+   const struct nlattr* nlattr;
+   struct taskstats stats;
+   int rem;
+   LinuxProcess* lp = (LinuxProcess*) linuxProcess;
+
+   nlhdr = nlmsg_hdr(nlmsg);
+
+   if (genlmsg_parse(nlhdr, 0, nlattrs, TASKSTATS_TYPE_MAX, NULL) < 0) {
+      return NL_SKIP;
+   }
+
+   if ((nlattr = nlattrs[TASKSTATS_TYPE_AGGR_PID]) || (nlattr = nlattrs[TASKSTATS_TYPE_NULL])) {
+      memcpy(&stats, nla_data(nla_next(nla_data(nlattr), &rem)), sizeof(stats));
+      assert(Process_getPid(&lp->super) == (pid_t)stats.ac_pid);
+
+      // The xxx_delay_total values wrap around on overflow.
+      // (Linux Kernel "Documentation/accounting/taskstats-struct.rst")
+      unsigned long long int timeDelta = stats.ac_etime * 1000 - lp->delay_read_time;
+      #define DELTAPERC(x, y) (timeDelta ? MINIMUM((float)((x) - (y)) / timeDelta * 100.0f, 100.0f) : NAN)
+      lp->cpu_delay_percent = DELTAPERC(stats.cpu_delay_total, lp->cpu_delay_total);
+      lp->blkio_delay_percent = DELTAPERC(stats.blkio_delay_total, lp->blkio_delay_total);
+      lp->swapin_delay_percent = DELTAPERC(stats.swapin_delay_total, lp->swapin_delay_total);
+      #undef DELTAPERC
+
+      lp->swapin_delay_total = stats.swapin_delay_total;
+      lp->blkio_delay_total = stats.blkio_delay_total;
+      lp->cpu_delay_total = stats.cpu_delay_total;
+      lp->delay_read_time = stats.ac_etime * 1000;
+   }
+   return NL_OK;
+}
+
+void LibNl_readDelayAcctData(LinuxProcessTable* this, LinuxProcess* process) {
+   struct nl_msg* msg;
+
+   if (!this->netlink_socket) {
+      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) {
+      goto delayacct_failure;
+   }
+
+   if (! (msg = nlmsg_alloc())) {
+      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)) {
+      nlmsg_free(msg);
+   }
+
+   if (nla_put_u32(msg, TASKSTATS_CMD_ATTR_PID, Process_getPid(&process->super)) < 0) {
+      nlmsg_free(msg);
+   }
+
+   if (nl_send_sync(this->netlink_socket, msg) < 0) {
+      goto delayacct_failure;
+   }
+
+   if (nl_recvmsgs_default(this->netlink_socket) < 0) {
+      goto delayacct_failure;
+   }
+
+   return;
+
+delayacct_failure:
+   process->swapin_delay_percent = NAN;
+   process->blkio_delay_percent = NAN;
+   process->cpu_delay_percent = NAN;
+}