URL-encode filenames in generated links

Makefile

@@ -5,8 +5,8 @@ CFLAGS+=-g -Wall -pedantic -std=c99 -D_POSIX_C_SOURCE=20120607L
 LIBS=-lmicrohttpd
 
 TARGET=fileshare
-SOURCE=main.c logger.c dirlisting.c
-DEPS=logger.h templates.h dirlisting.h
+SOURCE=main.c logger.c dirlisting.c util.c
+DEPS=logger.h templates.h dirlisting.h util.h
 
 OBJ=$(patsubst %.c, %.o, $(SOURCE))
 

dirlisting.c

@@ -14,6 +14,7 @@
 
 #include "logger.h"
 #include "templates.h"
+#include "util.h"
 
 #define FLG_USED 1
 #define FLG_ISDIR 2
@@ -58,6 +59,7 @@ char* gen_html(const char *url, struct Entry *entries, size_t numentries) {
   size_t i;
   char buf[256];
   char fullpath[PATH_MAX];
+  char encName[2*PATH_MAX];
 
   // allocate a buffer for the result string
   allocated = strlen(HEADER1 HEADER2 FOOTER) + 64 * numentries + 4096;
@@ -134,12 +136,14 @@ char* gen_html(const char *url, struct Entry *entries, size_t numentries) {
       result = tmpresult;
     }
 
+    urlencode(entries[i].name, encName);
+
     if(isrootdir) {
       sprintf(buf, "<li><a href=\"/%s/\">%s/</a></li>\n",
-          entries[i].name, entries[i].name);
+          encName, entries[i].name);
     } else {
       sprintf(buf, "<li><a href=\"%s/%s/\">%s/</a></li>\n",
-          url, entries[i].name, entries[i].name);
+          url, encName, entries[i].name);
     }
     strcat(result, buf);
   }
@@ -171,12 +175,14 @@ char* gen_html(const char *url, struct Entry *entries, size_t numentries) {
       result = tmpresult;
     }
 
+    urlencode(entries[i].name, encName);
+
     if(isrootdir) {
       sprintf(buf, "<li><a href=\"/%s\">%s</a> [%s]</li>\n",
-          entries[i].name, entries[i].name, format_size(entries[i].size));
+          encName, entries[i].name, format_size(entries[i].size));
     } else {
       sprintf(buf, "<li><a href=\"%s/%s\">%s</a> [%s]</li>\n",
-          url, entries[i].name, entries[i].name, format_size(entries[i].size));
+          url, encName, entries[i].name, format_size(entries[i].size));
     }
     strcat(result, buf);
   }

main.c

@@ -16,6 +16,7 @@
 #include "logger.h"
 #include "templates.h"
 #include "dirlisting.h"
+#include "util.h"
 
 #define DEFAULT_PORT 8888
 
@@ -32,13 +33,6 @@ struct MHD_Response *error500Response;
 
 int running = 1;
 
-void remove_trailing_slash(char *str) {
-  size_t offset = strlen(str)-1;
-  if((offset != 0) && (str[offset] == '/')) {
-    str[offset] = '\0';
-  }
-}
-
 void request_completed(void *cls,
                        struct MHD_Connection * connection,
                        void **ptr,

util.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "util.h"
+
+void remove_trailing_slash(char *str) {
+  size_t offset = strlen(str)-1;
+  if((offset != 0) && (str[offset] == '/')) {
+    str[offset] = '\0';
+  }
+}
+
+void urlencode(const char *str, char *result) {
+  uint8_t c;
+  while(*str) {
+    c = *str;
+
+    if((c >= 'a' && c <= 'z') ||
+        (c >= 'A' && c <= 'Z') ||
+        (c >= '0' && c <= '9') ||
+        c == '-' ||
+        c == '_' ||
+        c == '!' ||
+        c == '(' ||
+        c == ')' ||
+        c == '$' ||
+        c == '*' ||
+        c == '\'' ||
+        c == ',' ||
+        c == '.') {
+      // simply print safe characters
+      result += sprintf(result, "%c", c);
+    } else {
+      // encode all others
+      result += sprintf(result, "%%%02X", c);
+    }
+
+    str++;
+  }
+}

util.h

@@ -0,0 +1,7 @@
+#ifndef UTIL_H
+#define UTIL_H
+
+void remove_trailing_slash(char *str);
+void urlencode(const char *str, char *result);
+
+#endif // UTIL_H