Add SystemdMeter

1 files changed, 329 insertions, 0 deletions

diff --git a/linux/SystemdMeter.c b/linux/SystemdMeter.c
new file mode 100644
index 00000000..368d5cca
--- /dev/null
+++ b/linux/SystemdMeter.c
@@ -0,0 +1,329 @@
+/*
+htop - SystemdMeter.c
+(C) 2020 Christian Göttsche
+Released under the GNU GPLv2, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include "SystemdMeter.h"
+
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include "CRT.h"
+#include "XUtils.h"
+
+
+#define INVALID_VALUE ((unsigned int)-1)
+
+typedef void sd_bus;
+typedef void sd_bus_error;
+static int (*sym_sd_bus_open_system)(sd_bus**);
+static int (*sym_sd_bus_get_property_string)(sd_bus*, const char*, const char*, const char*, const char*, sd_bus_error*, char**);
+static int (*sym_sd_bus_get_property_trivial)(sd_bus*, const char*, const char*, const char*, const char*, sd_bus_error*, char, void*);
+static sd_bus* (*sym_sd_bus_unref)(sd_bus*);
+
+static char* systemState = NULL;
+static unsigned int nFailedUnits = INVALID_VALUE;
+static unsigned int nInstalledJobs = INVALID_VALUE;
+static unsigned int nNames = INVALID_VALUE;
+static unsigned int nJobs = INVALID_VALUE;
+static void* dlopenHandle = NULL;
+static sd_bus* bus = NULL;
+
+static void SystemdMeter_done(ATTR_UNUSED Meter* this) {
+   free(systemState);
+   systemState = NULL;
+
+   if (bus && dlopenHandle) {
+      sym_sd_bus_unref(bus);
+   }
+   bus = NULL;
+
+   if (dlopenHandle) {
+      dlclose(dlopenHandle);
+      dlopenHandle = NULL;
+   }
+}
+
+static int updateViaLib(void) {
+   if (!dlopenHandle) {
+      dlopenHandle = dlopen("libsystemd.so.0", RTLD_LAZY);
+      if (!dlopenHandle)
+         goto dlfailure;
+
+      /* Clear any errors */
+      dlerror();
+
+      #define resolve(symbolname) do {                                      \
+         *(void **)(&sym_##symbolname) = dlsym(dlopenHandle, #symbolname);  \
+         if (!sym_##symbolname || dlerror() != NULL)                        \
+            goto dlfailure;                                                 \
+      } while(0)
+
+      resolve(sd_bus_open_system);
+      resolve(sd_bus_get_property_string);
+      resolve(sd_bus_get_property_trivial);
+      resolve(sd_bus_unref);
+
+      #undef resolve
+   }
+
+   int r;
+
+   /* Connect to the system bus */
+   if (!bus) {
+      r = sym_sd_bus_open_system(&bus);
+      if (r < 0)
+         goto busfailure;
+   }
+
+   static const char* const busServiceName = "org.freedesktop.systemd1";
+   static const char* const busObjectPath = "/org/freedesktop/systemd1";
+   static const char* const busInterfaceName = "org.freedesktop.systemd1.Manager";
+
+   r = sym_sd_bus_get_property_string(bus,
+                                      busServiceName,        /* service to contact */
+                                      busObjectPath,         /* object path */
+                                      busInterfaceName,      /* interface name */
+                                      "SystemState",         /* property name */
+                                      NULL,                  /* object to return error in */
+                                      &systemState);
+   if (r < 0)
+      goto busfailure;
+
+   r = sym_sd_bus_get_property_trivial(bus,
+                                       busServiceName,       /* service to contact */
+                                       busObjectPath,        /* object path */
+                                       busInterfaceName,     /* interface name */
+                                       "NFailedUnits",       /* property name */
+                                       NULL,                 /* object to return error in */
+                                       'u',                  /* property type */
+                                       &nFailedUnits);
+   if (r < 0)
+      goto busfailure;
+
+   r = sym_sd_bus_get_property_trivial(bus,
+                                       busServiceName,       /* service to contact */
+                                       busObjectPath,        /* object path */
+                                       busInterfaceName,     /* interface name */
+                                       "NInstalledJobs",     /* property name */
+                                       NULL,                 /* object to return error in */
+                                       'u',                  /* property type */
+                                       &nInstalledJobs);
+   if (r < 0)
+      goto busfailure;
+
+   r = sym_sd_bus_get_property_trivial(bus,
+                                       busServiceName,       /* service to contact */
+                                       busObjectPath,        /* object path */
+                                       busInterfaceName,     /* interface name */
+                                       "NNames",             /* property name */
+                                       NULL,                 /* object to return error in */
+                                       'u',                  /* property type */
+                                       &nNames);
+   if (r < 0)
+      goto busfailure;
+
+   r = sym_sd_bus_get_property_trivial(bus,
+                                       busServiceName,       /* service to contact */
+                                       busObjectPath,        /* object path */
+                                       busInterfaceName,     /* interface name */
+                                       "NJobs",              /* property name */
+                                       NULL,                 /* object to return error in */
+                                       'u',                  /* property type */
+                                       &nJobs);
+   if (r < 0)
+      goto busfailure;
+
+   /* success */
+   return 0;
+
+busfailure:
+   sym_sd_bus_unref(bus);
+   bus = NULL;
+   return -2;
+
+dlfailure:
+   if (dlopenHandle) {
+      dlclose(dlopenHandle);
+      dlopenHandle = NULL;
+   }
+   return -1;
+}
+
+static void updateViaExec(void) {
+   int fdpair[2];
+   if (pipe(fdpair) < 0)
+      return;
+
+   pid_t child = fork();
+   if (child < 0) {
+      close(fdpair[1]);
+      close(fdpair[0]);
+      return;
+   }
+
+   if (child == 0) {
+      close(fdpair[0]);
+      dup2(fdpair[1], STDOUT_FILENO);
+      close(fdpair[1]);
+      int fdnull = open("/dev/null", O_WRONLY);
+      if (fdnull < 0)
+         exit(1);
+      dup2(fdnull, STDERR_FILENO);
+      close(fdnull);
+      execl("/bin/systemctl",
+            "/bin/systemctl",
+            "show",
+            "--property=SystemState",
+            "--property=NFailedUnits",
+            "--property=NNames",
+            "--property=NJobs",
+            "--property=NInstalledJobs",
+            NULL);
+      exit(127);
+   }
+   close(fdpair[1]);
+
+   int wstatus;
+   if (waitpid(child, &wstatus, 0) < 0 || !WIFEXITED(wstatus) || WEXITSTATUS(wstatus) != 0) {
+      close(fdpair[0]);
+      return;
+   }
+
+   FILE* commandOutput = fdopen(fdpair[0], "r");
+   if (!commandOutput) {
+      close(fdpair[0]);
+      return;
+   }
+
+   char lineBuffer[128];
+   while (fgets(lineBuffer, sizeof(lineBuffer), commandOutput)) {
+      if (String_startsWith(lineBuffer, "SystemState=")) {
+         char* newline = strchr(lineBuffer + strlen("SystemState="), '\n');
+         if (newline)
+            *newline = '\0';
+         systemState = xStrdup(lineBuffer + strlen("SystemState="));
+      } else if (String_startsWith(lineBuffer, "NFailedUnits=")) {
+         nFailedUnits = strtoul(lineBuffer + strlen("NFailedUnits="), NULL, 10);
+      } else if (String_startsWith(lineBuffer, "NNames=")) {
+         nNames = strtoul(lineBuffer + strlen("NNames="), NULL, 10);
+      } else if (String_startsWith(lineBuffer, "NJobs=")) {
+         nJobs = strtoul(lineBuffer + strlen("NJobs="), NULL, 10);
+      } else if (String_startsWith(lineBuffer, "NInstalledJobs=")) {
+         nInstalledJobs = strtoul(lineBuffer + strlen("NInstalledJobs="), NULL, 10);
+      }
+   }
+
+   fclose(commandOutput);
+}
+
+static void SystemdMeter_updateValues(ATTR_UNUSED Meter* this, char* buffer, int size) {
+   free(systemState);
+   systemState = NULL;
+   nFailedUnits = nInstalledJobs = nNames = nJobs = INVALID_VALUE;
+
+   if (updateViaLib() < 0)
+      updateViaExec();
+
+   xSnprintf(buffer, size, "%s", systemState ? systemState : "???");
+}
+
+static int zeroDigitColor(unsigned int value) {
+   switch (value) {
+   case 0:
+      return CRT_colors[METER_VALUE];
+   case INVALID_VALUE:
+      return CRT_colors[METER_VALUE_ERROR];
+   default:
+      return CRT_colors[METER_VALUE_NOTICE];
+   }
+}
+
+static int valueDigitColor(unsigned int value) {
+   switch (value) {
+      case 0:
+         return CRT_colors[METER_VALUE_NOTICE];
+      case INVALID_VALUE:
+         return CRT_colors[METER_VALUE_ERROR];
+      default:
+         return CRT_colors[METER_VALUE];
+   }
+}
+
+
+static void SystemdMeter_display(ATTR_UNUSED const Object* cast, RichString* out) {
+   char buffer[16];
+
+   int color = (systemState && 0 == strcmp(systemState, "running")) ? METER_VALUE_OK : METER_VALUE_ERROR;
+   RichString_write(out, CRT_colors[color], systemState ? systemState : "???");
+
+   RichString_append(out, CRT_colors[METER_TEXT], " (");
+
+   if (nFailedUnits == INVALID_VALUE) {
+      buffer[0] = '?';
+      buffer[1] = '\0';
+   } else {
+      xSnprintf(buffer, sizeof(buffer), "%u", nFailedUnits);
+   }
+   RichString_append(out, zeroDigitColor(nFailedUnits), buffer);
+
+   RichString_append(out, CRT_colors[METER_TEXT], "/");
+
+   if (nNames == INVALID_VALUE) {
+      buffer[0] = '?';
+      buffer[1] = '\0';
+   } else {
+      xSnprintf(buffer, sizeof(buffer), "%u", nNames);
+   }
+   RichString_append(out, valueDigitColor(nNames), buffer);
+
+   RichString_append(out, CRT_colors[METER_TEXT], " failed) (");
+
+   if (nJobs == INVALID_VALUE) {
+      buffer[0] = '?';
+      buffer[1] = '\0';
+   } else {
+      xSnprintf(buffer, sizeof(buffer), "%u", nJobs);
+   }
+   RichString_append(out, zeroDigitColor(nJobs), buffer);
+
+   RichString_append(out, CRT_colors[METER_TEXT], "/");
+
+   if (nInstalledJobs == INVALID_VALUE) {
+      buffer[0] = '?';
+      buffer[1] = '\0';
+   } else {
+      xSnprintf(buffer, sizeof(buffer), "%u", nInstalledJobs);
+   }
+   RichString_append(out, valueDigitColor(nInstalledJobs), buffer);
+
+   RichString_append(out, CRT_colors[METER_TEXT], " jobs)");
+}
+
+static const int SystemdMeter_attributes[] = {
+   METER_VALUE
+};
+
+const MeterClass SystemdMeter_class = {
+   .super = {
+      .extends = Class(Meter),
+      .delete = Meter_delete,
+      .display = SystemdMeter_display
+   },
+   .updateValues = SystemdMeter_updateValues,
+   .done = SystemdMeter_done,
+   .defaultMode = TEXT_METERMODE,
+   .maxItems = 0,
+   .total = 100.0,
+   .attributes = SystemdMeter_attributes,
+   .name = "Systemd",
+   .uiName = "Systemd state",
+   .description = "Systemd system state and unit overview",
+   .caption = "Systemd: ",
+};