Separate display from sampling in SysArch and Hostname Meters

Several of our newer meters have merged coding concerns in terms
of extracting values and displaying those values.  This commit
rectifies that for the SysArch and Hostname meters, allowing use
of this code with alternative front/back ends.  The SysArch code
is also refined to detect whether the platform has an os-release
file at all and/or the sys/utsname.h header via configure.ac.

14 files changed, 210 insertions, 77 deletions

diff --git a/Generic.c b/Generic.c
new file mode 100644
index 00000000..185ecb41
--- /dev/null
+++ b/Generic.c
@@ -0,0 +1,102 @@
+/*
+htop - Generic.c
+(C) 2021 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
+
+#include "Generic.h"
+
+#include <stdio.h>
+#ifdef HAVE_SYS_UTSNAME_H
+#include <sys/utsname.h>
+#endif
+#include <unistd.h>
+
+#include "XUtils.h"
+
+void Generic_Hostname(char* buffer, size_t size) {
+   gethostname(buffer, size - 1);
+}
+
+#ifdef HAVE_SYS_UTSNAME_H
+
+#ifndef OSRELEASEFILE
+#define OSRELEASEFILE "/etc/os-release"
+#endif
+
+static void parseOSRelease(char* buffer, size_t bufferLen) {
+   FILE* stream = fopen(OSRELEASEFILE, "r");
+   if (!stream) {
+      xSnprintf(buffer, bufferLen, "No OS Release");
+      return;
+   }
+
+   char name[64] = {'\0'};
+   char version[64] = {'\0'};
+   char lineBuffer[256];
+   while (fgets(lineBuffer, sizeof(lineBuffer), stream)) {
+      if (String_startsWith(lineBuffer, "PRETTY_NAME=\"")) {
+         const char* start = lineBuffer + strlen("PRETTY_NAME=\"");
+         const char* stop = strrchr(lineBuffer, '"');
+         if (!stop || stop <= start)
+            continue;
+         String_safeStrncpy(buffer, start, MINIMUM(bufferLen, (size_t)(stop - start + 1)));
+         fclose(stream);
+         return;
+      }
+      if (String_startsWith(lineBuffer, "NAME=\"")) {
+         const char* start = lineBuffer + strlen("NAME=\"");
+         const char* stop = strrchr(lineBuffer, '"');
+         if (!stop || stop <= start)
+            continue;
+         String_safeStrncpy(name, start, MINIMUM(sizeof(name), (size_t)(stop - start + 1)));
+         continue;
+      }
+      if (String_startsWith(lineBuffer, "VERSION=\"")) {
+         const char* start = lineBuffer + strlen("VERSION=\"");
+         const char* stop = strrchr(lineBuffer, '"');
+         if (!stop || stop <= start)
+            continue;
+         String_safeStrncpy(version, start, MINIMUM(sizeof(version), (size_t)(stop - start + 1)));
+         continue;
+      }
+   }
+   fclose(stream);
+
+   snprintf(buffer, bufferLen, "%s%s%s", name[0] ? name : "", name[0] && version[0] ? " " : "", version);
+}
+
+char* Generic_OSRelease(void) {
+   static struct utsname uname_info;
+
+   static char savedString[
+      /* uname structure fields - manpages recommend sizeof */
+      sizeof(uname_info.sysname) +
+      sizeof(uname_info.release) +
+      sizeof(uname_info.machine) +
+      16/*markup*/ +
+      128/*distro*/] = {'\0'};
+   static bool loaded_data = false;
+
+   if (!loaded_data) {
+      int uname_result = uname(&uname_info);
+
+      char distro[128];
+      parseOSRelease(distro, sizeof(distro));
+
+      if (uname_result == 0) {
+         size_t written = xSnprintf(savedString, sizeof(savedString), "%s %s [%s]", uname_info.sysname, uname_info.release, uname_info.machine);
+         if (!String_contains_i(savedString, distro) && sizeof(savedString) > written)
+            snprintf(savedString + written, sizeof(savedString) - written, " @ %s", distro);
+      } else {
+         snprintf(savedString, sizeof(savedString), "%s", distro);
+      }
+
+      loaded_data = true;
+   }
+
+   return savedString;
+}
+#endif
diff --git a/Generic.h b/Generic.h
new file mode 100644
index 00000000..44adc09e
--- /dev/null
+++ b/Generic.h
@@ -0,0 +1,16 @@
+#ifndef HEADER_Generic
+#define HEADER_Generic
+/*
+htop - Generic.h
+(C) 2021 htop dev team
+Released under the GNU GPLv2, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include <stddef.h>
+
+void Generic_Hostname(char* buffer, size_t size);
+
+char* Generic_OSRelease(void);
+
+#endif
diff --git a/HostnameMeter.c b/HostnameMeter.c
index af8e3493..924def11 100644
--- a/HostnameMeter.c
+++ b/HostnameMeter.c
@@ -8,6 +8,7 @@ in the source distribution for its full text.
 #include "config.h" // IWYU pragma: keep
 
 #include "HostnameMeter.h"
+#include "Platform.h"
 
 #include <unistd.h>
 
@@ -19,9 +20,8 @@ static const int HostnameMeter_attributes[] = {
    HOSTNAME
 };
 
-static void HostnameMeter_updateValues(Meter* this, char* buffer, size_t size) {
-   (void) this;
-   gethostname(buffer, size - 1);
+static void HostnameMeter_updateValues(ATTR_UNUSED Meter* this, char* buffer, size_t size) {
+   Platform_getHostname(buffer, size);
 }
 
 const MeterClass HostnameMeter_class = {
diff --git a/Makefile.am b/Makefile.am
index 0498fc8a..082f6e7a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -42,6 +42,7 @@ myhtopsources = \
 	DisplayOptionsPanel.c \
 	EnvScreen.c \
 	FunctionBar.c \
+	Generic.c \
 	Hashtable.c \
 	Header.c \
 	HostnameMeter.c \
@@ -96,6 +97,7 @@ myhtopheaders = \
 	DisplayOptionsPanel.h \
 	EnvScreen.h \
 	FunctionBar.h \
+	Generic.h \
 	Hashtable.h \
 	Header.h \
 	HostnameMeter.h \
diff --git a/SysArchMeter.c b/SysArchMeter.c
index cc962630..c368e944 100644
--- a/SysArchMeter.c
+++ b/SysArchMeter.c
@@ -6,90 +6,21 @@ in the source distribution for its full text.
 */
 #include "config.h"  // IWYU pragma: keep
 
+#include "Platform.h"
 #include "SysArchMeter.h"
 
-#include <stdio.h>
-#include <sys/utsname.h>
-
 #include "XUtils.h"
 
 
 static const int SysArchMeter_attributes[] = {HOSTNAME};
 
-static void parseOSRelease(char* buffer, size_t bufferLen) {
-   FILE* stream = fopen("/etc/os-release", "r");
-   if (!stream) {
-      stream = fopen("/usr/lib/os-release", "r");
-      if (!stream) {
-         xSnprintf(buffer, bufferLen, "Unknown Distro");
-         return;
-      }
-   }
-
-   char name[64] = {'\0'};
-   char version[64] = {'\0'};
-   char lineBuffer[256];
-   while (fgets(lineBuffer, sizeof(lineBuffer), stream)) {
-      if (String_startsWith(lineBuffer, "PRETTY_NAME=\"")) {
-         const char* start = lineBuffer + strlen("PRETTY_NAME=\"");
-         const char* stop = strrchr(lineBuffer, '"');
-         if (!stop || stop <= start)
-            continue;
-         String_safeStrncpy(buffer, start, MINIMUM(bufferLen, (size_t)(stop - start + 1)));
-         fclose(stream);
-         return;
-      }
-      if (String_startsWith(lineBuffer, "NAME=\"")) {
-         const char* start = lineBuffer + strlen("NAME=\"");
-         const char* stop = strrchr(lineBuffer, '"');
-         if (!stop || stop <= start)
-            continue;
-         String_safeStrncpy(name, start, MINIMUM(sizeof(name), (size_t)(stop - start + 1)));
-         continue;
-      }
-      if (String_startsWith(lineBuffer, "VERSION=\"")) {
-         const char* start = lineBuffer + strlen("VERSION=\"");
-         const char* stop = strrchr(lineBuffer, '"');
-         if (!stop || stop <= start)
-            continue;
-         String_safeStrncpy(version, start, MINIMUM(sizeof(version), (size_t)(stop - start + 1)));
-         continue;
-      }
-   }
-   fclose(stream);
-
-   snprintf(buffer, bufferLen, "%s%s%s", name[0] ? name : "", name[0] && version[0] ? " " : "", version);
-}
-
 static void SysArchMeter_updateValues(ATTR_UNUSED Meter* this, char* buffer, size_t size) {
-   static char savedString[
-      /* uname structure fields - manpages recommend sizeof */
-      sizeof(((struct utsname*)0)->sysname) +
-      sizeof(((struct utsname*)0)->release) +
-      sizeof(((struct utsname*)0)->machine) +
-      16/*markup*/ +
-      128/*distro*/] = {'\0'};
-   static bool loaded_data = false;
-
-   if (!loaded_data) {
-      struct utsname uname_info;
-      int uname_result = uname(&uname_info);
-
-      char distro[128];
-      parseOSRelease(distro, sizeof(distro));
-
-      if (uname_result == 0) {
-         size_t written = xSnprintf(savedString, sizeof(savedString), "%s %s [%s]", uname_info.sysname, uname_info.release, uname_info.machine);
-         if (!String_contains_i(savedString, distro) && sizeof(savedString) > written)
-            snprintf(savedString + written, sizeof(savedString) - written, " @ %s", distro);
-      } else {
-         snprintf(savedString, sizeof(savedString), "%s", distro);
-      }
+   static char* string;
 
-      loaded_data = true;
-   }
+   if (string == NULL)
+      Platform_getRelease(&string);
 
-   String_safeStrncpy(buffer, savedString, size);
+   String_safeStrncpy(buffer, string, size);
 }
 
 const MeterClass SysArchMeter_class = {
diff --git a/configure.ac b/configure.ac
index ee7e8ee5..95b01143 100644
--- a/configure.ac
+++ b/configure.ac
@@ -108,6 +108,7 @@ AC_CHECK_HEADERS([ \
     strings.h \
     sys/param.h \
     sys/time.h \
+    sys/utsname.h \
     unistd.h
    ], [], [AC_MSG_ERROR([can not find required generic header files])])
 
@@ -316,6 +317,18 @@ case "$enable_hwloc" in
       ;;
 esac
 
+AC_ARG_WITH([os-release],
+            [AS_HELP_STRING([--with-os-release=FILE],
+			    [location of an os-release file @<:@default=/etc/os-release@:>@])],
+            [],
+            [with_os_release=/etc/os-release])
+if test -n "$with_os_release" -a ! -f "$with_os_release"; then
+   if test -f "/usr/lib/os-release"; then
+      with_os_release="/usr/lib/os-release"
+   fi
+fi
+AC_DEFINE_UNQUOTED([OSRELEASEFILE], ["$with_os_release"], [File with OS release details.])
+
 # ----------------------------------------------------------------------
 
 
@@ -608,6 +621,7 @@ AC_MSG_RESULT([
   ${PACKAGE_NAME} ${VERSION}
 
   platform:                  $my_htop_platform
+  os-release file:           $with_os_release
   (Linux) proc directory:    $with_proc
   (Linux) openvz:            $enable_openvz
   (Linux) vserver:           $enable_vserver
diff --git a/darwin/Platform.h b/darwin/Platform.h
index 2a97270a..59c2b9c7 100644
--- a/darwin/Platform.h
+++ b/darwin/Platform.h
@@ -16,6 +16,7 @@ in the source distribution for its full text.
 #include "CPUMeter.h"
 #include "DarwinProcess.h"
 #include "DiskIOMeter.h"
+#include "Generic.h"
 #include "NetworkIOMeter.h"
 #include "ProcessLocksScreen.h"
 #include "SignalsPanel.h"
@@ -67,4 +68,12 @@ bool Platform_getNetworkIO(NetworkIOData* data);
 
 void Platform_getBattery(double *percent, ACPresence *isOnAC);
 
+static inline void Platform_getHostname(char* buffer, size_t size) {
+   Generic_Hostname(buffer, size);
+}
+
+static inline void Platform_getRelease(char** string) {
+   *string = Generic_OSRelease();
+}
+
 #endif
diff --git a/dragonflybsd/Platform.h b/dragonflybsd/Platform.h
index 1ae13938..4d70e4b7 100644
--- a/dragonflybsd/Platform.h
+++ b/dragonflybsd/Platform.h
@@ -14,6 +14,7 @@ in the source distribution for its full text.
 #include "Action.h"
 #include "BatteryMeter.h"
 #include "DiskIOMeter.h"
+#include "Generic.h"
 #include "NetworkIOMeter.h"
 #include "ProcessLocksScreen.h"
 #include "SignalsPanel.h"
@@ -57,4 +58,12 @@ bool Platform_getNetworkIO(NetworkIOData* data);
 
 void Platform_getBattery(double* percent, ACPresence* isOnAC);
 
+static inline void Platform_getHostname(char* buffer, size_t size) {
+   Generic_Hostname(buffer, size);
+}
+
+static inline void Platform_getRelease(char** string) {
+   *string = Generic_OSRelease();
+}
+
 #endif
diff --git a/freebsd/Platform.h b/freebsd/Platform.h
index 8f25d83a..4ec130d7 100644
--- a/freebsd/Platform.h
+++ b/freebsd/Platform.h
@@ -13,6 +13,7 @@ in the source distribution for its full text.
 #include "Action.h"
 #include "BatteryMeter.h"
 #include "DiskIOMeter.h"
+#include "Generic.h"
 #include "Meter.h"
 #include "NetworkIOMeter.h"
 #include "Process.h"
@@ -62,4 +63,12 @@ bool Platform_getNetworkIO(NetworkIOData* data);
 
 void Platform_getBattery(double* percent, ACPresence* isOnAC);
 
+static inline void Platform_getHostname(char* buffer, size_t size) {
+   Generic_Hostname(buffer, size);
+}
+
+static inline void Platform_getRelease(char** string) {
+   *string = Generic_OSRelease();
+}
+
 #endif
diff --git a/linux/Platform.h b/linux/Platform.h
index f932c583..c2a86f73 100644
--- a/linux/Platform.h
+++ b/linux/Platform.h
@@ -14,6 +14,7 @@ in the source distribution for its full text.
 #include "Action.h"
 #include "BatteryMeter.h"
 #include "DiskIOMeter.h"
+#include "Generic.h"
 #include "Meter.h"
 #include "NetworkIOMeter.h"
 #include "Process.h"
@@ -72,4 +73,12 @@ bool Platform_getNetworkIO(NetworkIOData* data);
 
 void Platform_getBattery(double *percent, ACPresence *isOnAC);
 
+static inline void Platform_getHostname(char* buffer, size_t size) {
+   Generic_Hostname(buffer, size);
+}
+
+static inline void Platform_getRelease(char** string) {
+   *string = Generic_OSRelease();
+}
+
 #endif
diff --git a/openbsd/Platform.h b/openbsd/Platform.h
index 66b804de..ca739988 100644
--- a/openbsd/Platform.h
+++ b/openbsd/Platform.h
@@ -14,6 +14,7 @@ in the source distribution for its full text.
 #include "Action.h"
 #include "BatteryMeter.h"
 #include "DiskIOMeter.h"
+#include "Generic.h"
 #include "Meter.h"
 #include "NetworkIOMeter.h"
 #include "Process.h"
@@ -60,4 +61,12 @@ bool Platform_getNetworkIO(NetworkIOData* data);
 
 void Platform_getBattery(double* percent, ACPresence* isOnAC);
 
+static inline void Platform_getHostname(char* buffer, size_t size) {
+   Generic_Hostname(buffer, size);
+}
+
+static inline void Platform_getRelease(char** string) {
+   *string = Generic_OSRelease();
+}
+
 #endif
diff --git a/solaris/Platform.h b/solaris/Platform.h
index 08636ef9..d4496bc2 100644
--- a/solaris/Platform.h
+++ b/solaris/Platform.h
@@ -19,6 +19,7 @@ in the source distribution for its full text.
 #include "Action.h"
 #include "BatteryMeter.h"
 #include "DiskIOMeter.h"
+#include "Generic.h"
 #include "NetworkIOMeter.h"
 #include "ProcessLocksScreen.h"
 #include "SignalsPanel.h"
@@ -79,4 +80,12 @@ bool Platform_getNetworkIO(NetworkIOData* data);
 
 void Platform_getBattery(double* percent, ACPresence* isOnAC);
 
+static inline void Platform_getHostname(char* buffer, size_t size) {
+   Generic_Hostname(buffer, size);
+}
+
+static inline void Platform_getRelease(char** string) {
+   *string = Generic_OSRelease();
+}
+
 #endif
diff --git a/unsupported/Platform.c b/unsupported/Platform.c
index 5791acca..9dc457b7 100644
--- a/unsupported/Platform.c
+++ b/unsupported/Platform.c
@@ -64,6 +64,8 @@ const MeterClass* const Platform_meterTypes[] = {
    NULL
 };
 
+static const char Platform_unsupported[] = "unsupported";
+
 void Platform_init(void) {
    /* no platform-specific setup needed */
 }
@@ -146,3 +148,11 @@ void Platform_getBattery(double* percent, ACPresence* isOnAC) {
    *percent = NAN;
    *isOnAC = AC_ERROR;
 }
+
+void Platform_getHostname(char* buffer, size_t size) {
+   String_safeStrncpy(buffer, Platform_unsupported, size);
+}
+
+void Platform_getRelease(char** string) {
+    *string = xStrdup(Platform_unsupported);
+}
diff --git a/unsupported/Platform.h b/unsupported/Platform.h
index 9b98fd97..837daca4 100644
--- a/unsupported/Platform.h
+++ b/unsupported/Platform.h
@@ -57,4 +57,8 @@ bool Platform_getNetworkIO(NetworkIOData* data);
 
 void Platform_getBattery(double *percent, ACPresence *isOnAC);
 
+void Platform_getHostname(char* buffer, size_t size);
+
+void Platform_getRelease(char** string);
+
 #endif