LM (Linux): support version detection

src/detection/lm/lm.h

@@ -9,8 +9,7 @@ typedef struct FFLMResult
 {
     FFstrbuf service;
     FFstrbuf type;
-    // bool isDisplay;
-    // bool remote;
+    FFstrbuf version;
 } FFLMResult;
 
 const char* ffDetectLM(FFLMResult* result);

src/detection/lm/lm_linux.c

@@ -1,6 +1,7 @@
 #include "lm.h"
 #include "common/properties.h"
 #include "common/dbus.h"
+#include "common/processing.h"
 #include "detection/displayserver/displayserver.h"
 
 #include <unistd.h>
@@ -8,6 +9,90 @@
 #define FF_SYSTEMD_SESSIONS_PATH "/var/run/systemd/sessions/"
 #define FF_SYSTEMD_USERS_PATH "/run/systemd/users/"
 
+static const char* getGdmVersion(FFstrbuf* version)
+{
+    const char* error = ffProcessAppendStdOut(version, (char* const[]) {
+        "gdm",
+        "--version",
+        NULL
+    });
+    if (error)
+        return error;
+
+    // GDM 44.1
+    ffStrbufSubstrAfterFirstC(version, ' ');
+    return NULL;
+}
+
+#ifdef FF_HAVE_ZLIB
+#include "common/library.h"
+#include <stdlib.h>
+#include <zlib.h>
+
+static const char* getSddmVersion(FFstrbuf* version)
+{
+    FF_LIBRARY_LOAD(zlib, &instance.config.libZ, "dlopen libz failed", "libz" FF_LIBRARY_EXTENSION, 2)
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(zlib, gzopen);
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(zlib, gzread);
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(zlib, gzerror);
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(zlib, gztell);
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(zlib, gzrewind);
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(zlib, gzclose);
+
+    gzFile file = ffgzopen("/usr/share/man/man1/sddm.1.gz", "rb");
+    if (file == Z_NULL)
+        return "ffgzopen(\"/usr/share/man/man1/sddm.1.gz\", \"rb\") failed";
+
+    ffStrbufEnsureFree(version, 2047);
+    memset(version->chars, 0, version->allocated);
+    int size = ffgzread(file, version->chars, version->allocated - 1);
+    ffgzclose(file);
+
+    if (size <= 0)
+        return "ffgzread(file, version->chars, version->length) failed";
+
+    version->length = (uint32_t) size;
+    uint32_t index = ffStrbufFirstIndexS(version, ".TH ");
+    if (index == version->length)
+    {
+        ffStrbufClear(version);
+        return ".TH is not found";
+    }
+
+    ffStrbufSubstrBefore(version, ffStrbufNextIndexC(version, index, '\n'));
+    ffStrbufSubstrAfter(version, index + strlen(".TH "));
+
+    // "SDDM" 1 "May 2014" "sddm 0.20.0" "sddm"
+    ffStrbufSubstrBeforeLastC(version, ' ');
+    ffStrbufTrimRight(version, '"');
+    ffStrbufSubstrAfterLastC(version, ' ');
+
+    return NULL;
+}
+#else
+static const char* getSddmVersion(FF_MAYBE_UNUSED FFstrbuf* version)
+{
+    return "Fastfetch is built without libz support";
+}
+#endif
+
+static const char* getXfwmVersion(FFstrbuf* version)
+{
+    const char* error = ffProcessAppendStdOut(version, (char* const[]) {
+        "xfwm4",
+        "--version",
+        NULL
+    });
+    if (error)
+        return error;
+
+    //         This is xfwm4 version 4.18.0 (revision 7e7473c5b) for Xfce 4.18...
+    ffStrbufSubstrAfterFirstS(version, "version ");
+    ffStrbufSubstrBeforeFirstC(version, ' ');
+
+    return NULL;
+}
+
 const char* ffDetectLM(FFLMResult* result)
 {
     FF_STRBUF_AUTO_DESTROY path = ffStrbufCreate();
@@ -38,6 +123,13 @@ const char* ffDetectLM(FFLMResult* result)
     }))
         return "Failed to parse /run/systemd/sessions/$XDG_SESSION_ID";
 
+    if (ffStrbufStartsWithS(&result->service, "gdm"))
+        getGdmVersion(&result->version);
+    else if (ffStrbufStartsWithS(&result->service, "sddm"))
+        getSddmVersion(&result->version);
+    else if (ffStrbufStartsWithS(&result->service, "xfwm"))
+        getXfwmVersion(&result->version);
+
     // Correct char cases
     if (ffStrbufIgnCaseEqualS(&result->type, FF_WM_PROTOCOL_WAYLAND))
         ffStrbufSetS(&result->type, FF_WM_PROTOCOL_WAYLAND);