diff --git a/examples/esp32/Makefile b/examples/esp32/Makefile
index bdf03ca6..ee2290a8 100644
--- a/examples/esp32/Makefile
+++ b/examples/esp32/Makefile
@@ -9,7 +9,7 @@ example: main/main.c Makefile
 COMPORT ?= /dev/cu.SLAB_USBtoUART
 ESPTOOL ?= esptool.py
 flash:
-	cd build && $(ESPTOOL) --chip esp32 -p $(COMPORT) -b 460800 --before=default_reset --after=hard_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 2MB 0x8000 partition_table/partition-table.bin 0x1000 bootloader/bootloader.bin 0x10000 mongoose-esp32-example.bin
+	cd build && $(ESPTOOL) --chip esp32 -p $(COMPORT) -b 460800 --before=default_reset --after=hard_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 2MB 0x8000 partition_table/partition-table.bin 0x1000 bootloader/bootloader.bin 0x100000 mongoose-esp32-example.bin
 
 clean:
 	rm -rf $(PROG) *.o *.dSYM *.gcov *.gcno *.gcda *.obj *.exe *.ilk *.pdb mongoose mongoose_* mongoose.* build sdkconfig
diff --git a/examples/esp32/main/CMakeLists.txt b/examples/esp32/main/CMakeLists.txt
index 5ca8e861..2dcf0bed 100644
--- a/examples/esp32/main/CMakeLists.txt
+++ b/examples/esp32/main/CMakeLists.txt
@@ -2,3 +2,4 @@ idf_component_register(SRCS "main.c"
                             "wifi.c"
                             "../../../mongoose.c"
                        INCLUDE_DIRS "../../..")
+component_compile_options(-DMG_ENABLE_DIRECTORY_LISTING=1 -DMG_ENABLE_LINES)
diff --git a/examples/esp32/main/main.c b/examples/esp32/main/main.c
index 1b92198a..4d508f4f 100644
--- a/examples/esp32/main/main.c
+++ b/examples/esp32/main/main.c
@@ -1,54 +1,53 @@
 // Copyright (c) 2020 Cesanta Software Limited
 // All rights reserved
 
+#include "esp_spiffs.h"
+#include "freertos/FreeRTOS.h"
 #include "mongoose.h"
 
 #define WIFI_SSID "WIFI_NETWORK"   // SET THIS!
 #define WIFI_PASS "WIFI_PASSWORD"  // SET THIS!
+#define FS_ROOT "/spiffs"
 
-#define SERVER_URL "http://0.0.0.0:80"
-#define CLIENT_URL "http://info.cern.ch"
-
-// Event handler for an server (accepted) connection
+// Event handler for an server (accepted) connection. Implemented endpoints:
+//    /api/stats  - return JSON object with ESP32 stats (free RAM)
+//    any other   - serve files from the filesystem
 static void cb(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
   if (ev == MG_EV_HTTP_MSG) {
-    mg_http_reply(c, 200, "", "Hello from ESP!\n");
+    struct mg_http_message *hm = ev_data;
+    if (mg_http_match_uri(hm, "/api/stats")) {
+      mg_http_reply(c, 200, "", "{\"ram\": %lu}\n", xPortGetFreeHeapSize());
+    } else {
+      struct mg_http_serve_opts opts = {.root_dir = FS_ROOT};
+      mg_http_serve_dir(c, hm, &opts);
+    }
   }
 }
 
-// Event handler for a client connection - fetch the first web page in history
-// To enable TLS for HTTP,
-//   1. Copy "ca.pem" file to the ESP32 flash FS
-//   2. Add TLS init snippet for the connection, see examples/http-client
-static void cb2(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
-  if (ev == MG_EV_CONNECT) {
-    struct mg_str s = mg_url_host(CLIENT_URL);
-    mg_printf(c, "GET / HTTP/1.0\r\nHost: %.*s\r\n\r\n", (int) s.len, s.ptr);
-  } else if (ev == MG_EV_HTTP_MSG) {
-    struct mg_http_message *hm = ev_data;  // Print HTTP response
-    LOG(LL_INFO, ("Fetched:\n%.*s", (int) hm->message.len, hm->message.ptr));
-    c->is_closing = 1;
-  }
-}
-
-// Called after we're connected to WiFi network
-static void run_mongoose(void) {
-  struct mg_mgr mgr;
-  mg_log_set("3");
-  mg_mgr_init(&mgr);
-  mg_http_listen(&mgr, SERVER_URL, cb, &mgr);    // Listening server
-  mg_http_connect(&mgr, CLIENT_URL, cb2, &mgr);  // Example client
-  LOG(LL_INFO, ("Starting Mongoose web server v%s", MG_VERSION));
-  for (;;) mg_mgr_poll(&mgr, 1000);
-  mg_mgr_free(&mgr);
+// SPIFFS is flat, so tell Mongoose that the FS root is a directory
+// This cludge is not required for filesystems with directory support
+bool mg_is_dir(const char *path) {
+  return strcmp(path, FS_ROOT) == 0;
 }
 
 void app_main(void) {
+  // Mount filesystem
+  esp_vfs_spiffs_conf_t conf = {
+      .base_path = FS_ROOT, .max_files = 20, .format_if_mount_failed = true};
+  int res = esp_vfs_spiffs_register(&conf);
+  LOG(res == ESP_OK ? LL_INFO : LL_ERROR, ("FS %s, %d", conf.base_path, res));
+  mg_file_printf(FS_ROOT "/hello.txt", "%s", "hello from ESP");
+
   // Setup wifi. This function is implemented in wifi.c
   // It blocks until connected to the configured WiFi network
   void wifi_init(const char *ssid, const char *pass);
   wifi_init(WIFI_SSID, WIFI_PASS);
 
-  // Done connecting to WiFi, now start HTTP server
-  run_mongoose();
+  // Connected to WiFi, now start HTTP server
+  struct mg_mgr mgr;
+  mg_log_set("3");
+  mg_mgr_init(&mgr);
+  mg_http_listen(&mgr, "http://0.0.0.0:80", cb, &mgr);  // Listening server
+  LOG(LL_INFO, ("Starting Mongoose web server v%s", MG_VERSION));
+  for (;;) mg_mgr_poll(&mgr, 1000);  // Infinite event loop
 }
diff --git a/examples/esp32/partitions.csv b/examples/esp32/partitions.csv
new file mode 100644
index 00000000..8ab9ab77
--- /dev/null
+++ b/examples/esp32/partitions.csv
@@ -0,0 +1,5 @@
+# Name,   Type, SubType, Offset,  Size, Flags
+nvs,      data, nvs,     0x9000,  0x6000,
+phy_init, data, phy,     0xf000,  0x1000,
+storage,  data, spiffs,  0x10000, 0x10000,
+factory,  app,  factory, 0x100000, 1M,
diff --git a/examples/esp32/sdkconfig.defaults b/examples/esp32/sdkconfig.defaults
new file mode 100644
index 00000000..8ff365b1
--- /dev/null
+++ b/examples/esp32/sdkconfig.defaults
@@ -0,0 +1,3 @@
+CONFIG_PARTITION_TABLE_CUSTOM=y
+CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions.csv"
+CONFIG_PARTITION_TABLE_FILENAME="partitions.csv"
diff --git a/mongoose.c b/mongoose.c
index 0c1df381..ada38118 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -483,7 +483,7 @@ int mg_http_get_var(const struct mg_str *buf, const char *name, char *dst,
         s = (const char *) memchr(p, '&', (size_t)(e - p));
         if (s == NULL) s = e;
         len = mg_url_decode(p, (size_t)(s - p), dst, dst_len, 1);
-        if (len == -1) len = -3;  // Failed to decode
+        if (len < 0) len = -3;  // Failed to decode
         break;
       }
     }
@@ -511,7 +511,7 @@ int mg_url_decode(const char *src, size_t src_len, char *dst, size_t dst_len,
     }
   }
   if (j < dst_len) dst[j] = '\0';  // Null-terminate the destination
-  return i >= src_len ? (int) j : -1;
+  return i >= src_len && j < dst_len ? (int) j : -1;
 }
 
 int mg_http_get_request_len(const unsigned char *buf, size_t buf_len) {
@@ -819,21 +819,23 @@ void mg_http_serve_file(struct mg_connection *c, struct mg_http_message *hm,
     MG_ARCH == MG_ARCH_FREERTOS
 char *realpath(const char *src, char *dst) {
   int len = strlen(src);
-  if (len > PATH_MAX - 1) len = PATH_MAX - 1;
+  if (len > MG_PATH_MAX - 1) len = MG_PATH_MAX - 1;
   strncpy(dst, src, len);
   dst[len] = '\0';
+  LOG(LL_DEBUG, ("[%s] -> [%s]", src, dst));
   return dst;
 }
 #endif
 
-// Try to avoid dirent API
-static int mg_is_dir(const char *path) {
+// Allow user to override this function
+bool mg_is_dir(const char *path) WEAK;
+bool mg_is_dir(const char *path) {
 #if MG_ARCH == MG_ARCH_FREERTOS
   struct FF_STAT st;
   return (ff_stat(path, &st) == 0) && (st.st_mode & FF_IFDIR);
 #else
-  struct stat st;
-  return (stat(path, &st) == 0) && (st.st_mode & S_IFDIR);
+  mg_stat_t st;
+  return mg_stat(path, &st) == 0 && S_ISDIR(st.st_mode);
 #endif
 }
 
@@ -978,7 +980,7 @@ static void printdirentry(struct mg_connection *c, struct mg_http_message *hm,
 
 static void listdir(struct mg_connection *c, struct mg_http_message *hm,
                     char *dir) {
-  char path[PATH_MAX + 1], *p = &dir[strlen(dir) - 1], tmp[10];
+  char path[MG_PATH_MAX], *p = &dir[strlen(dir) - 1], tmp[10];
   struct dirent *dp;
   DIR *dirp;
 
@@ -997,14 +999,17 @@ static void listdir(struct mg_connection *c, struct mg_http_message *hm,
               (int) hm->uri.len, hm->uri.ptr, (int) hm->uri.len, hm->uri.ptr);
     while ((dp = readdir(dirp)) != NULL) {
       mg_stat_t st;
+      const char *sep = dp->d_name[0] == MG_DIRSEP ? "/" : "";
       // Do not show current dir and hidden files
       if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")) continue;
-      snprintf(path, sizeof(path), "%s/%s", dir, dp->d_name);
-      if (mg_stat(path, &st) != 0) {
+      // SPIFFS can report "/foo.txt" in the dp->d_name
+      if (snprintf(path, sizeof(path), "%s%s%s", dir, sep, dp->d_name) < 0) {
+        LOG(LL_ERROR, ("%s truncated", dp->d_name));
+      } else if (mg_stat(path, &st) != 0) {
         LOG(LL_ERROR, ("%lu stat(%s): %d", c->id, path, errno));
-        continue;
+      } else {
+        printdirentry(c, hm, dp->d_name, &st);
       }
-      printdirentry(c, hm, dp->d_name, &st);
     }
     closedir(dirp);
     mg_printf(c,
@@ -1022,59 +1027,70 @@ static void listdir(struct mg_connection *c, struct mg_http_message *hm,
 
 void mg_http_serve_dir(struct mg_connection *c, struct mg_http_message *hm,
                        struct mg_http_serve_opts *opts) {
-  char path[PATH_MAX + 2], root[sizeof(path) - 2], real[sizeof(path) - 2];
-  path[0] = root[0] = real[0] = '\0';
-  if (realpath(opts->root_dir, root) == NULL)
-    LOG(LL_DEBUG, ("realpath(%s): %d", opts->root_dir, errno));
-  if (!mg_is_dir(root)) {
-    mg_http_reply(c, 400, "", "Bad web root [%s]\n", root);
+  char t1[MG_PATH_MAX], t2[sizeof(t1)];
+  t1[0] = t2[0] = '\0';
+
+  if (realpath(opts->root_dir, t1) == NULL)
+    LOG(LL_ERROR, ("realpath(%s): %d", opts->root_dir, errno));
+
+  LOG(LL_DEBUG, ("realpath(%s) -> [%s] %zu", opts->root_dir, t1, sizeof(t1)));
+
+  if (!mg_is_dir(t1)) {
+    mg_http_reply(c, 400, "", "Bad web root [%s]\n", t1);
   } else {
-    char dec[PATH_MAX];
     // NOTE(lsm): Xilinx snprintf does not 0-terminate the detination for
     // the %.*s specifier, if the length is zero. Make sure hm->uri.len > 0
     bool is_index = false;
-    int ndec = mg_url_decode(hm->uri.ptr, hm->uri.len, dec, sizeof(dec), 0);
-    size_t n =
-        snprintf(path, sizeof(path), "%s%.*s", root, ndec < 0 ? 0 : ndec, dec);
-    while (n > 0 && n < sizeof(path) && path[n - 1] == '/') path[--n] = 0;
-    if (realpath(path, real) == NULL)
-      LOG(LL_DEBUG, ("realpath(%s): %d", path, errno));
-    // LOG(LL_INFO, ("[%s] [%s] [%s] [%s]", dir, root, path, real));
-    if (mg_is_dir(real)) {
-      strncat(real, "/index.html", sizeof(real) - strlen(real) - 1);
-      real[sizeof(real) - 1] = '\0';
+    size_t n1 = strlen(t1), n2;
+
+    mg_url_decode(hm->uri.ptr, hm->uri.len, t1 + n1, sizeof(t1) - n1, 0);
+    t1[sizeof(t1) - 1] = '\0';
+    n2 = strlen(t1);
+    while (n2 > 0 && t1[n2 - 1] == '/') t1[--n2] = 0;
+
+    if (realpath(t1, t2) == NULL)
+      LOG(LL_ERROR, ("realpath(%s): %d", t1, errno));
+
+    if (mg_is_dir(t2)) {
+      strncat(t2, "/index.html", sizeof(t2) - strlen(t2) - 1);
+      t2[sizeof(t2) - 1] = '\0';
       is_index = true;
     }
-    if (strlen(real) < strlen(root) || memcmp(real, root, strlen(root)) != 0) {
+
+    LOG(LL_DEBUG, (" --> [%s] [%s] %zu", t1, t2, sizeof(t1)));
+
+    if (strlen(t2) < n1 || memcmp(t1, t2, n1) != 0) {
+      // Requested file is located outside root directory, fail
       mg_http_reply(c, 404, "", "Not found %.*s\n", hm->uri.len, hm->uri.ptr);
     } else {
-      FILE *fp = fopen(real, "r");
+      FILE *fp = fopen(t2, "r");
 #if MG_ENABLE_SSI
       if (is_index && fp == NULL) {
-        char *p = real + strlen(real);
-        while (p > real && p[-1] != '/') p--;
-        strncpy(p, "index.shtml", &real[sizeof(real)] - p - 2);
-        real[sizeof(real) - 1] = '\0';
-        fp = fopen(real, "r");
+        char *p = t2 + strlen(t2);
+        while (p > t2 && p[-1] != '/') p--;
+        strncpy(p, "index.shtml", &t2[sizeof(t2)] - p - 2);
+        t2[sizeof(t2) - 1] = '\0';
+        fp = fopen(t2, "r");
       }
 #endif
 #if MG_ENABLE_HTTP_DEBUG_ENDPOINT
-      snprintf(c->label, sizeof(c->label) - 1, "<-F %s", real);
+      snprintf(c->label, sizeof(c->label) - 1, "<-F %s", t2);
 #endif
       if (is_index && fp == NULL) {
 #if MG_ENABLE_DIRECTORY_LISTING
-        listdir(c, hm, real);
+        listdir(c, hm, t2);
 #else
         mg_http_reply(c, 403, "", "%s", "Directory listing not supported");
 #endif
 #if MG_ENABLE_SSI
       } else if (opts->ssi_pattern != NULL &&
-                 mg_globmatch(opts->ssi_pattern, strlen(opts->ssi_pattern),
-                              real, strlen(real))) {
-        mg_http_serve_ssi(c, root, real);
+                 mg_globmatch(opts->ssi_pattern, strlen(opts->ssi_pattern), t2,
+                              strlen(t2))) {
+        t1[n1] = '\0';
+        mg_http_serve_ssi(c, t1, t2);
 #endif
       } else {
-        mg_http_serve_file(c, hm, real, guess_content_type(real), NULL);
+        mg_http_serve_file(c, hm, t2, guess_content_type(t2), NULL);
       }
       if (fp != NULL) fclose(fp);
     }
@@ -3058,7 +3074,7 @@ static char *mg_ssi(const char *path, const char *root, int depth) {
       if (intag && ch == '>' && buf[len - 1] == '-' && buf[len - 2] == '-') {
         buf[len++] = ch & 0xff;
         if (sscanf(buf, "<!--#include file=\"%[^\"]", arg)) {
-          char tmp[PATH_MAX], *p = (char *) path + strlen(path), *data;
+          char tmp[MG_PATH_MAX], *p = (char *) path + strlen(path), *data;
           while (p > path && p[-1] != MG_DIRSEP && p[-1] != '/') p--;
           snprintf(tmp, sizeof(tmp), "%.*s%s", (int) (p - path), path, arg);
           if (depth < MG_MAX_SSI_DEPTH &&
@@ -3069,7 +3085,7 @@ static char *mg_ssi(const char *path, const char *root, int depth) {
             LOG(LL_ERROR, ("%s: file=%s error or too deep", path, arg));
           }
         } else if (sscanf(buf, "<!--#include virtual=\"%[^\"]", arg)) {
-          char tmp[PATH_MAX], *data;
+          char tmp[MG_PATH_MAX], *data;
           snprintf(tmp, sizeof(tmp), "%s%s", root, arg);
           if (depth < MG_MAX_SSI_DEPTH &&
               (data = mg_ssi(tmp, root, depth + 1)) != NULL) {
@@ -3755,7 +3771,7 @@ char *mg_file_read(const char *path) {
 bool mg_file_write(const char *path, const void *buf, size_t len) {
   bool result = false;
   FILE *fp;
-  char tmp[PATH_MAX];
+  char tmp[MG_PATH_MAX];
   snprintf(tmp, sizeof(tmp), "%s.%d", path, rand());
   fp = fopen(tmp, "wb");
   if (fp != NULL) {
diff --git a/mongoose.h b/mongoose.h
index 6350cb1d..fc883dc7 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -120,8 +120,12 @@
 
 #include <dirent.h>
 #include <netdb.h>
+#include <sys/stat.h>
 #define MG_DIRSEP '/'
 #define MG_INT64_FMT "%lld"
+#ifndef MG_PATH_MAX
+#define MG_PATH_MAX 128
+#endif
 
 #endif
 
@@ -351,6 +355,10 @@ typedef int socklen_t;
 #define MG_MAX_HTTP_HEADERS 40
 #endif
 
+#ifndef MG_PATH_MAX
+#define MG_PATH_MAX PATH_MAX
+#endif
+
 
 #include <ctype.h>
 #include <string.h>
diff --git a/src/arch_esp32.h b/src/arch_esp32.h
index a50711b3..3ad98e8f 100644
--- a/src/arch_esp32.h
+++ b/src/arch_esp32.h
@@ -4,7 +4,11 @@
 
 #include <dirent.h>
 #include <netdb.h>
+#include <sys/stat.h>
 #define MG_DIRSEP '/'
 #define MG_INT64_FMT "%lld"
+#ifndef MG_PATH_MAX
+#define MG_PATH_MAX 128
+#endif
 
 #endif
diff --git a/src/config.h b/src/config.h
index d01120ac..2a83c945 100644
--- a/src/config.h
+++ b/src/config.h
@@ -67,3 +67,7 @@
 #ifndef MG_MAX_HTTP_HEADERS
 #define MG_MAX_HTTP_HEADERS 40
 #endif
+
+#ifndef MG_PATH_MAX
+#define MG_PATH_MAX PATH_MAX
+#endif
diff --git a/src/http.c b/src/http.c
index 9d81fbc6..f0869a27 100644
--- a/src/http.c
+++ b/src/http.c
@@ -63,7 +63,7 @@ int mg_http_get_var(const struct mg_str *buf, const char *name, char *dst,
         s = (const char *) memchr(p, '&', (size_t)(e - p));
         if (s == NULL) s = e;
         len = mg_url_decode(p, (size_t)(s - p), dst, dst_len, 1);
-        if (len == -1) len = -3;  // Failed to decode
+        if (len < 0) len = -3;  // Failed to decode
         break;
       }
     }
@@ -91,7 +91,7 @@ int mg_url_decode(const char *src, size_t src_len, char *dst, size_t dst_len,
     }
   }
   if (j < dst_len) dst[j] = '\0';  // Null-terminate the destination
-  return i >= src_len ? (int) j : -1;
+  return i >= src_len && j < dst_len ? (int) j : -1;
 }
 
 int mg_http_get_request_len(const unsigned char *buf, size_t buf_len) {
@@ -399,21 +399,23 @@ void mg_http_serve_file(struct mg_connection *c, struct mg_http_message *hm,
     MG_ARCH == MG_ARCH_FREERTOS
 char *realpath(const char *src, char *dst) {
   int len = strlen(src);
-  if (len > PATH_MAX - 1) len = PATH_MAX - 1;
+  if (len > MG_PATH_MAX - 1) len = MG_PATH_MAX - 1;
   strncpy(dst, src, len);
   dst[len] = '\0';
+  LOG(LL_DEBUG, ("[%s] -> [%s]", src, dst));
   return dst;
 }
 #endif
 
-// Try to avoid dirent API
-static int mg_is_dir(const char *path) {
+// Allow user to override this function
+bool mg_is_dir(const char *path) WEAK;
+bool mg_is_dir(const char *path) {
 #if MG_ARCH == MG_ARCH_FREERTOS
   struct FF_STAT st;
   return (ff_stat(path, &st) == 0) && (st.st_mode & FF_IFDIR);
 #else
-  struct stat st;
-  return (stat(path, &st) == 0) && (st.st_mode & S_IFDIR);
+  mg_stat_t st;
+  return mg_stat(path, &st) == 0 && S_ISDIR(st.st_mode);
 #endif
 }
 
@@ -558,7 +560,7 @@ static void printdirentry(struct mg_connection *c, struct mg_http_message *hm,
 
 static void listdir(struct mg_connection *c, struct mg_http_message *hm,
                     char *dir) {
-  char path[PATH_MAX + 1], *p = &dir[strlen(dir) - 1], tmp[10];
+  char path[MG_PATH_MAX], *p = &dir[strlen(dir) - 1], tmp[10];
   struct dirent *dp;
   DIR *dirp;
 
@@ -577,14 +579,17 @@ static void listdir(struct mg_connection *c, struct mg_http_message *hm,
               (int) hm->uri.len, hm->uri.ptr, (int) hm->uri.len, hm->uri.ptr);
     while ((dp = readdir(dirp)) != NULL) {
       mg_stat_t st;
+      const char *sep = dp->d_name[0] == MG_DIRSEP ? "/" : "";
       // Do not show current dir and hidden files
       if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")) continue;
-      snprintf(path, sizeof(path), "%s/%s", dir, dp->d_name);
-      if (mg_stat(path, &st) != 0) {
+      // SPIFFS can report "/foo.txt" in the dp->d_name
+      if (snprintf(path, sizeof(path), "%s%s%s", dir, sep, dp->d_name) < 0) {
+        LOG(LL_ERROR, ("%s truncated", dp->d_name));
+      } else if (mg_stat(path, &st) != 0) {
         LOG(LL_ERROR, ("%lu stat(%s): %d", c->id, path, errno));
-        continue;
+      } else {
+        printdirentry(c, hm, dp->d_name, &st);
       }
-      printdirentry(c, hm, dp->d_name, &st);
     }
     closedir(dirp);
     mg_printf(c,
@@ -602,59 +607,70 @@ static void listdir(struct mg_connection *c, struct mg_http_message *hm,
 
 void mg_http_serve_dir(struct mg_connection *c, struct mg_http_message *hm,
                        struct mg_http_serve_opts *opts) {
-  char path[PATH_MAX + 2], root[sizeof(path) - 2], real[sizeof(path) - 2];
-  path[0] = root[0] = real[0] = '\0';
-  if (realpath(opts->root_dir, root) == NULL)
-    LOG(LL_DEBUG, ("realpath(%s): %d", opts->root_dir, errno));
-  if (!mg_is_dir(root)) {
-    mg_http_reply(c, 400, "", "Bad web root [%s]\n", root);
+  char t1[MG_PATH_MAX], t2[sizeof(t1)];
+  t1[0] = t2[0] = '\0';
+
+  if (realpath(opts->root_dir, t1) == NULL)
+    LOG(LL_ERROR, ("realpath(%s): %d", opts->root_dir, errno));
+
+  LOG(LL_DEBUG, ("realpath(%s) -> [%s] %zu", opts->root_dir, t1, sizeof(t1)));
+
+  if (!mg_is_dir(t1)) {
+    mg_http_reply(c, 400, "", "Bad web root [%s]\n", t1);
   } else {
-    char dec[PATH_MAX];
     // NOTE(lsm): Xilinx snprintf does not 0-terminate the detination for
     // the %.*s specifier, if the length is zero. Make sure hm->uri.len > 0
     bool is_index = false;
-    int ndec = mg_url_decode(hm->uri.ptr, hm->uri.len, dec, sizeof(dec), 0);
-    size_t n =
-        snprintf(path, sizeof(path), "%s%.*s", root, ndec < 0 ? 0 : ndec, dec);
-    while (n > 0 && n < sizeof(path) && path[n - 1] == '/') path[--n] = 0;
-    if (realpath(path, real) == NULL)
-      LOG(LL_DEBUG, ("realpath(%s): %d", path, errno));
-    // LOG(LL_INFO, ("[%s] [%s] [%s] [%s]", dir, root, path, real));
-    if (mg_is_dir(real)) {
-      strncat(real, "/index.html", sizeof(real) - strlen(real) - 1);
-      real[sizeof(real) - 1] = '\0';
+    size_t n1 = strlen(t1), n2;
+
+    mg_url_decode(hm->uri.ptr, hm->uri.len, t1 + n1, sizeof(t1) - n1, 0);
+    t1[sizeof(t1) - 1] = '\0';
+    n2 = strlen(t1);
+    while (n2 > 0 && t1[n2 - 1] == '/') t1[--n2] = 0;
+
+    if (realpath(t1, t2) == NULL)
+      LOG(LL_ERROR, ("realpath(%s): %d", t1, errno));
+
+    if (mg_is_dir(t2)) {
+      strncat(t2, "/index.html", sizeof(t2) - strlen(t2) - 1);
+      t2[sizeof(t2) - 1] = '\0';
       is_index = true;
     }
-    if (strlen(real) < strlen(root) || memcmp(real, root, strlen(root)) != 0) {
+
+    LOG(LL_DEBUG, (" --> [%s] [%s] %zu", t1, t2, sizeof(t1)));
+
+    if (strlen(t2) < n1 || memcmp(t1, t2, n1) != 0) {
+      // Requested file is located outside root directory, fail
       mg_http_reply(c, 404, "", "Not found %.*s\n", hm->uri.len, hm->uri.ptr);
     } else {
-      FILE *fp = fopen(real, "r");
+      FILE *fp = fopen(t2, "r");
 #if MG_ENABLE_SSI
       if (is_index && fp == NULL) {
-        char *p = real + strlen(real);
-        while (p > real && p[-1] != '/') p--;
-        strncpy(p, "index.shtml", &real[sizeof(real)] - p - 2);
-        real[sizeof(real) - 1] = '\0';
-        fp = fopen(real, "r");
+        char *p = t2 + strlen(t2);
+        while (p > t2 && p[-1] != '/') p--;
+        strncpy(p, "index.shtml", &t2[sizeof(t2)] - p - 2);
+        t2[sizeof(t2) - 1] = '\0';
+        fp = fopen(t2, "r");
       }
 #endif
 #if MG_ENABLE_HTTP_DEBUG_ENDPOINT
-      snprintf(c->label, sizeof(c->label) - 1, "<-F %s", real);
+      snprintf(c->label, sizeof(c->label) - 1, "<-F %s", t2);
 #endif
       if (is_index && fp == NULL) {
 #if MG_ENABLE_DIRECTORY_LISTING
-        listdir(c, hm, real);
+        listdir(c, hm, t2);
 #else
         mg_http_reply(c, 403, "", "%s", "Directory listing not supported");
 #endif
 #if MG_ENABLE_SSI
       } else if (opts->ssi_pattern != NULL &&
-                 mg_globmatch(opts->ssi_pattern, strlen(opts->ssi_pattern),
-                              real, strlen(real))) {
-        mg_http_serve_ssi(c, root, real);
+                 mg_globmatch(opts->ssi_pattern, strlen(opts->ssi_pattern), t2,
+                              strlen(t2))) {
+        t1[n1] = '\0';
+        mg_http_serve_ssi(c, t1, t2);
 #endif
       } else {
-        mg_http_serve_file(c, hm, real, guess_content_type(real), NULL);
+        mg_http_serve_file(c, hm, t2, guess_content_type(t2), NULL);
       }
       if (fp != NULL) fclose(fp);
     }
diff --git a/src/ssi.c b/src/ssi.c
index b2b822e2..0417d51c 100644
--- a/src/ssi.c
+++ b/src/ssi.c
@@ -17,7 +17,7 @@ static char *mg_ssi(const char *path, const char *root, int depth) {
       if (intag && ch == '>' && buf[len - 1] == '-' && buf[len - 2] == '-') {
         buf[len++] = ch & 0xff;
         if (sscanf(buf, "<!--#include file=\"%[^\"]", arg)) {
-          char tmp[PATH_MAX], *p = (char *) path + strlen(path), *data;
+          char tmp[MG_PATH_MAX], *p = (char *) path + strlen(path), *data;
           while (p > path && p[-1] != MG_DIRSEP && p[-1] != '/') p--;
           snprintf(tmp, sizeof(tmp), "%.*s%s", (int) (p - path), path, arg);
           if (depth < MG_MAX_SSI_DEPTH &&
@@ -28,7 +28,7 @@ static char *mg_ssi(const char *path, const char *root, int depth) {
             LOG(LL_ERROR, ("%s: file=%s error or too deep", path, arg));
           }
         } else if (sscanf(buf, "<!--#include virtual=\"%[^\"]", arg)) {
-          char tmp[PATH_MAX], *data;
+          char tmp[MG_PATH_MAX], *data;
           snprintf(tmp, sizeof(tmp), "%s%s", root, arg);
           if (depth < MG_MAX_SSI_DEPTH &&
               (data = mg_ssi(tmp, root, depth + 1)) != NULL) {
diff --git a/src/util.c b/src/util.c
index 697bd4c0..6dbbd170 100644
--- a/src/util.c
+++ b/src/util.c
@@ -34,7 +34,7 @@ char *mg_file_read(const char *path) {
 bool mg_file_write(const char *path, const void *buf, size_t len) {
   bool result = false;
   FILE *fp;
-  char tmp[PATH_MAX];
+  char tmp[MG_PATH_MAX];
   snprintf(tmp, sizeof(tmp), "%s.%d", path, rand());
   fp = fopen(tmp, "wb");
   if (fp != NULL) {