tpws: check broken gzip and zlib errors

tpws/gzip.c

@@ -73,3 +73,9 @@ zerr:
  }
  return r;
 }
+
+bool is_gzip(FILE* F)
+{
+ unsigned char magic[2];
+ return !fseek(F,0,SEEK_SET) && fread(magic, 1, 2, F)==2 && magic[0]==0x1F && magic[1]==0x8B;
+}

tpws/gzip.h

@@ -2,5 +2,7 @@
 
 #include <stdio.h>
 #include <zlib.h>
+#include <stdbool.h>
 
 int z_readfile(FILE *F,char **buf,size_t *size);
+bool is_gzip(FILE* F);

tpws/hostlist.c

@@ -28,6 +28,7 @@ bool LoadHostList(strpool **hostlist, char *filename)
 	size_t zsize;
 	int ct = 0;
 	FILE *F;
+	int r;
 	
 	if (*hostlist)
 	{
@@ -40,10 +41,10 @@ bool LoadHostList(strpool **hostlist, char *filename)
 		fprintf(stderr, "Could not open %s\n", filename);
 		return false;
 	}
-	if (z_readfile(F,&zbuf,&zsize)==Z_OK)
+	if ((r=z_readfile(F,&zbuf,&zsize))==Z_OK)
 	{
 	
-		printf("libz compression detected. uncompressed size : %zu\n", zsize);
+		printf("zlib compression detected. uncompressed size : %zu\n", zsize);
 		fclose(F);
 		
 		p = zbuf;
@@ -60,9 +61,21 @@ bool LoadHostList(strpool **hostlist, char *filename)
 		}
 		free(zbuf);
 	}
+	else if (r!=Z_DATA_ERROR)
+	{
+		fprintf(stderr, "zlib decompression failed : result %d\n",r);
+		return false;
+	}
 	else
 	{
+		if (is_gzip(F))
+		{
+			fprintf(stderr, "hostlist is gzip but is broken : %s\n",filename);
+			return false;
+		}
+		
 		fseek(F,0,SEEK_SET);
+		printf("loading plain text list\n",r);
 		
 		while (fgets(s, 256, F))
 		{