curl_path: make Curl_get_pathname use dynbuf

... instead of malloc and memcpy

- unit test 2604 verifies Curl_get_pathname()

Closes #13550

lib/curl_path.c

@@ -98,8 +98,8 @@ CURLcode Curl_getworkingpath(struct Curl_easy *data,
   return CURLE_OK;
 }
 
-/* The get_pathname() function is being borrowed from OpenSSH sftp.c
-   version 4.6p1. */
+/* The original get_pathname() function came from OpenSSH sftp.c version
+   4.6p1. */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -115,38 +115,37 @@ CURLcode Curl_getworkingpath(struct Curl_easy *data,
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
-CURLcode Curl_get_pathname(const char **cpp, char **path, char *homedir)
+
+#define MAX_PATHLENGTH 65535 /* arbitrary long */
+
+CURLcode Curl_get_pathname(const char **cpp, char **path, const char *homedir)
 {
   const char *cp = *cpp, *end;
   char quot;
-  unsigned int i, j;
-  size_t fullPathLength, pathLength;
-  bool relativePath = false;
+  unsigned int i;
   static const char WHITESPACE[] = " \t\r\n";
+  struct dynbuf out;
+  CURLcode result;
 
   DEBUGASSERT(homedir);
-  if(!*cp || !homedir) {
-    *cpp = NULL;
-    *path = NULL;
+  *path = NULL;
+  *cpp = NULL;
+  if(!*cp || !homedir)
     return CURLE_QUOTE_ERROR;
-  }
+
+  Curl_dyn_init(&out, MAX_PATHLENGTH);
+
   /* Ignore leading whitespace */
   cp += strspn(cp, WHITESPACE);
-  /* Allocate enough space for home directory and filename + separator */
-  fullPathLength = strlen(cp) + strlen(homedir) + 2;
-  *path = malloc(fullPathLength);
-  if(!*path)
-    return CURLE_OUT_OF_MEMORY;
 
   /* Check for quoted filenames */
   if(*cp == '\"' || *cp == '\'') {
     quot = *cp++;
 
     /* Search for terminating quote, unescape some chars */
-    for(i = j = 0; i <= strlen(cp); i++) {
+    for(i = 0; i <= strlen(cp); i++) {
       if(cp[i] == quot) {  /* Found quote */
         i++;
-        (*path)[j] = '\0';
         break;
       }
       if(cp[i] == '\0') {  /* End of string */
@@ -159,40 +158,45 @@ CURLcode Curl_get_pathname(const char **cpp, char **path, char *homedir)
           goto fail;
         }
       }
-      (*path)[j++] = cp[i];
+      result = Curl_dyn_addn(&out, &cp[i], 1);
+      if(result)
+        return result;
     }
 
-    if(j == 0) {
+    if(!Curl_dyn_len(&out))
       goto fail;
-    }
-    *cpp = cp + i + strspn(cp + i, WHITESPACE);
+
+    /* return pointer to second parameter if it exists */
+    *cpp = &cp[i] + strspn(&cp[i], WHITESPACE);
   }
   else {
     /* Read to end of filename - either to whitespace or terminator */
     end = strpbrk(cp, WHITESPACE);
     if(!end)
       end = strchr(cp, '\0');
+
     /* return pointer to second parameter if it exists */
     *cpp = end + strspn(end, WHITESPACE);
-    pathLength = 0;
-    relativePath = (cp[0] == '/' && cp[1] == '~' && cp[2] == '/');
+
     /* Handling for relative path - prepend home directory */
-    if(relativePath) {
-      strcpy(*path, homedir);
-      pathLength = strlen(homedir);
-      (*path)[pathLength++] = '/';
-      (*path)[pathLength] = '\0';
+    if(cp[0] == '/' && cp[1] == '~' && cp[2] == '/') {
+      result = Curl_dyn_add(&out, homedir);
+      if(!result)
+        result = Curl_dyn_addn(&out, "/", 1);
+      if(result)
+        return result;
       cp += 3;
     }
     /* Copy path name up until first "whitespace" */
-    memcpy(&(*path)[pathLength], cp, (int)(end - cp));
-    pathLength += (int)(end - cp);
-    (*path)[pathLength] = '\0';
+    result = Curl_dyn_addn(&out, cp, (end - cp));
+    if(result)
+      return result;
   }
+  *path = Curl_dyn_ptr(&out);
   return CURLE_OK;
 
 fail:
-  Curl_safefree(*path);
+  Curl_dyn_free(&out);
   return CURLE_QUOTE_ERROR;
 }
 

lib/curl_path.h

@@ -45,5 +45,5 @@ CURLcode Curl_getworkingpath(struct Curl_easy *data,
                              char *homedir,
                              char **path);
 
-CURLcode Curl_get_pathname(const char **cpp, char **path, char *homedir);
+CURLcode Curl_get_pathname(const char **cpp, char **path, const char *homedir);
 #endif /* HEADER_CURL_PATH_H */