add support for downloadable zip mod packages

getmod modname
  Try to download mods/modname.zip from all configured package servers.
  Does not automatically activate the mod. The zip files are limited to
  one megabyte total.

DOCREF getmod

source/src/autodownload.cpp

@@ -221,6 +221,11 @@ bool requirepackage(int type, const char *name, const char *host)
             pck->exts = mapexts;
             break;
 
+        case PCK_MOD:
+            prefix = "mods/";
+            forceext = ".zip";
+            break;
+
         default:
             conoutf("\f3requirepackage: illegal package type %d (\"%s\")", type, name); // should probably be fatal()
             delete pck;
@@ -230,7 +235,7 @@ bool requirepackage(int type, const char *name, const char *host)
     copystring(upath, name);
     unixpath(upath);
     filtertext(pck->name, name, FTXT__MEDIAFILEPATH); // also changes backslashes to slashes
-    if(strlen(upath) > 100 || strcmp(upath, pck->name) || (checkprefix && strncmp(pck->name, checkprefix, strlen(checkprefix))))
+    if(strlen(upath) > 100 || strcmp(upath, pck->name) || (checkprefix && strncmp(pck->name, checkprefix, strlen(checkprefix))) || (type == PCK_MOD && !validzipmodname(upath)))
     {
         conoutf("\f3requirepackage: illegal media path \"%s\" (type: %d)", name, type);
         delete pck;
@@ -305,7 +310,7 @@ void processdownload(package *pck, stream *f) // write downloaded data to file(s
         stream *d = openfile(path(pck->fullpath, true), "wb");
         if(d)
         {
-            streamcopy(d, f, MAXMEDIADOWNLOADFILESIZE);
+            streamcopy(d, f, pck->type == PCK_MOD ? MAXMODDOWNLOADSIZE : MAXMEDIADOWNLOADFILESIZE);
             delete d;
         }
         delete f;
@@ -493,3 +498,10 @@ void writepcksourcecfg()
         delete f;
     }
 }
+
+void getmod(char *name)
+{
+    if(requirepackage(PCK_MOD, name) && downloadpackages()) conoutf("mod package %s successfully downloaded", name);
+    else conoutf("failed to download mod package %s", name);
+}
+COMMAND(getmod, "s");

source/src/protocol.h

@@ -12,6 +12,7 @@
 #define MAXMAPSENDSIZE 65536
 #define MAXCFGFILESIZE 65536
 #define MAXMEDIADOWNLOADFILESIZE 1024000 // hard cap on filesizes (raw and unzipped) - to limit the effect of zip bombs - no nice error messages: just cap
+#define MAXMODDOWNLOADSIZE 1024000      // hard cap on the filesize of downloaded mod packages - to keep stuff reasonable
 #define MAXFILESINADZIP 21              // max number of files extracted from a zip by autodownload
 
 extern bool modprotocol;

source/src/protos.h

@@ -371,7 +371,7 @@ extern Texture *crosshairs[];
 extern void drawcrosshair(playerent *p, int n, struct color *c = NULL, float size = -1.0f);
 
 // autodownload
-enum { PCK_TEXTURE = 0, PCK_SKYBOX, PCK_MAPMODEL, PCK_AUDIO, PCK_MAP, PCK_NUM };
+enum { PCK_TEXTURE = 0, PCK_SKYBOX, PCK_MAPMODEL, PCK_AUDIO, PCK_MAP, PCK_MOD, PCK_NUM };
 extern int autodownload;
 extern void setupautodownload();
 extern void pollautodownloadresponse();

source/src/tools.h

@@ -963,6 +963,7 @@ extern void listfilesrecursive(const char *dir, vector<char *> &files, int level
 extern void listzipfiles(const char *dir, const char *ext, vector<char *> &files);
 extern bool delfile(const char *path);
 extern void backup(char *name, char *backupname);
+extern bool validzipmodname(char *name);
 extern void *zipmanualopen(stream *f, vector<const char *> &files);
 extern stream *zipmanualstream(void *a, int n);
 extern int zipmanualread(void *a, int n, stream *f, int maxlen = INT_MAX);

source/src/zip.cpp

@@ -498,6 +498,11 @@ const char *fixzipname(char *name) // check, if valid path + filename, based on
     return path(pname);
 }
 
+bool validzipmodname(char *name) // check for valid _downloadable_ zip mod name (no '#' allowed), also changes backslashes to slashes
+{
+    return fixzipname(name) && !strchr(name, '#');
+}
+
 VAR(zipcachemaxsize, 0, 512, 1024); // load zip files smaller than 512K straight into RAM
 
 void addzipmod(char *name)