tool_ipfs: simplify the ipfs gateway logic

- make sure memory allocated by libcurl is freed with curl_free()

- drop the ensure_trailing_slash complexity

Closes #19097

src/tool_ipfs.c

@@ -30,100 +30,70 @@
 #include "tool_ipfs.h"
 #include "memdebug.h" /* keep this as LAST include */
 
-/* ensure input ends in slash */
-static CURLcode ensure_trailing_slash(char **input)
+/* input string ends in slash? */
+static bool has_trailing_slash(const char *input)
 {
-  if(*input && **input) {
-    size_t len = strlen(*input);
-    if(((*input)[len - 1] != '/')) {
-      struct dynbuf dyn;
-      curlx_dyn_init(&dyn, len + 2);
-
-      if(curlx_dyn_addn(&dyn, *input, len)) {
-        tool_safefree(*input);
-        return CURLE_OUT_OF_MEMORY;
-      }
-
-      tool_safefree(*input);
-
-      if(curlx_dyn_addn(&dyn, "/", 1))
-        return CURLE_OUT_OF_MEMORY;
-
-      *input = curlx_dyn_ptr(&dyn);
-    }
-  }
-
-  return CURLE_OK;
+  size_t len = strlen(input);
+  return (len && input[len - 1] == '/');
 }
 
 static char *ipfs_gateway(void)
 {
-  char *ipfs_path = NULL;
-  char *gateway_composed_file_path = NULL;
-  FILE *gateway_file = NULL;
-  char *gateway = curl_getenv("IPFS_GATEWAY");
+  char *ipfs_path_c = NULL;
+  char *gateway_composed_c = NULL;
+  FILE *gfile = NULL;
+  char *gateway_env = getenv("IPFS_GATEWAY");
 
-  /* Gateway is found from environment variable. */
-  if(gateway) {
-    if(ensure_trailing_slash(&gateway))
-      goto fail;
-    return gateway;
-  }
+  if(gateway_env)
+    return strdup(gateway_env);
 
   /* Try to find the gateway in the IPFS data folder. */
-  ipfs_path = curl_getenv("IPFS_PATH");
+  ipfs_path_c = curl_getenv("IPFS_PATH");
 
-  if(!ipfs_path) {
+  if(!ipfs_path_c) {
     char *home = getenv("HOME");
-    if(home && *home)
-      ipfs_path = curl_maprintf("%s/.ipfs/", home);
     /* fallback to "~/.ipfs", as that is the default location. */
+    if(home && *home)
+      ipfs_path_c = curl_maprintf("%s/.ipfs/", home);
+    if(!ipfs_path_c)
+      goto fail;
   }
 
-  if(!ipfs_path || ensure_trailing_slash(&ipfs_path))
+  gateway_composed_c =
+    curl_maprintf("%s%sgateway", ipfs_path_c,
+                  has_trailing_slash(ipfs_path_c) ? "" : "/");
+
+  if(!gateway_composed_c)
     goto fail;
 
-  gateway_composed_file_path = curl_maprintf("%sgateway", ipfs_path);
+  gfile = curlx_fopen(gateway_composed_c, FOPEN_READTEXT);
+  curl_free(gateway_composed_c);
 
-  if(!gateway_composed_file_path)
-    goto fail;
-
-  gateway_file = curlx_fopen(gateway_composed_file_path, FOPEN_READTEXT);
-  tool_safefree(gateway_composed_file_path);
-
-  if(gateway_file) {
+  if(gfile) {
     int c;
     struct dynbuf dyn;
+    char *gateway = NULL;
     curlx_dyn_init(&dyn, MAX_GATEWAY_URL_LEN);
 
     /* get the first line of the gateway file, ignore the rest */
-    while((c = getc(gateway_file)) != EOF && c != '\n' && c != '\r') {
+    while((c = getc(gfile)) != EOF && c != '\n' && c != '\r') {
       char c_char = (char)c;
       if(curlx_dyn_addn(&dyn, &c_char, 1))
         goto fail;
     }
 
-    curlx_fclose(gateway_file);
-    gateway_file = NULL;
-
     if(curlx_dyn_len(&dyn))
       gateway = curlx_dyn_ptr(&dyn);
 
-    if(gateway)
-      ensure_trailing_slash(&gateway);
-
-    if(!gateway)
-      goto fail;
-
-    tool_safefree(ipfs_path);
+    curl_free(ipfs_path_c);
+    curlx_fclose(gfile);
 
     return gateway;
   }
 fail:
-  if(gateway_file)
-    curlx_fclose(gateway_file);
-  tool_safefree(gateway);
-  tool_safefree(ipfs_path);
+  if(gfile)
+    curlx_fclose(gfile);
+  curl_free(ipfs_path_c);
   return NULL;
 }
 
@@ -161,20 +131,13 @@ CURLcode ipfs_url_rewrite(CURLU *uh, const char *protocol, char **url,
    * if we do have something but if it is an invalid url.
    */
   if(config->ipfs_gateway) {
-    /* ensure the gateway ends in a trailing / */
-    if(ensure_trailing_slash(&config->ipfs_gateway) != CURLE_OK) {
-      result = CURLE_OUT_OF_MEMORY;
-      goto clean;
-    }
-
     if(!curl_url_set(gatewayurl, CURLUPART_URL, config->ipfs_gateway,
-                    CURLU_GUESS_SCHEME)) {
+                     CURLU_GUESS_SCHEME)) {
       gateway = strdup(config->ipfs_gateway);
       if(!gateway) {
         result = CURLE_URL_MALFORMAT;
         goto clean;
       }
-
     }
     else {
       result = CURLE_BAD_FUNCTION_ARGUMENT;
@@ -182,7 +145,6 @@ CURLcode ipfs_url_rewrite(CURLU *uh, const char *protocol, char **url,
     }
   }
   else {
-    /* this is ensured to end in a trailing / within ipfs_gateway() */
     gateway = ipfs_gateway();
     if(!gateway) {
       result = CURLE_FILE_COULDNT_READ_FILE;
@@ -230,10 +192,10 @@ CURLcode ipfs_url_rewrite(CURLU *uh, const char *protocol, char **url,
   if(inputpath && (inputpath[0] == '/') && !inputpath[1])
     *inputpath = '\0';
 
-  /* ensure the gateway path ends with a trailing slash */
-  ensure_trailing_slash(&gwpath);
 
-  pathbuffer = curl_maprintf("%s%s/%s%s", gwpath, protocol, cid,
+  pathbuffer = curl_maprintf("%s%s%s/%s%s", gwpath,
+                             has_trailing_slash(gwpath) ? "" : "/",
+                             protocol, cid,
                              inputpath ? inputpath : "");
   if(!pathbuffer) {
     goto clean;