altsvc: keep a copy of the file name to survive handle reset

The alt-svc cache survives a call to curl_easy_reset fine, but the file
name to use for saving the cache was cleared. Now the alt-svc cache has
a copy of the file name to survive handle resets.

Added test 1908 to verify.

Reported-by: Craig Andrews
Fixes #4898
Closes #4902

1 files changed, 16 insertions, 1 deletions

diff --git a/lib/altsvc.c b/lib/altsvc.c
index 93cc302bd..c05562985 100644
--- a/lib/altsvc.c
+++ b/lib/altsvc.c
@@ -185,7 +185,16 @@ static CURLcode altsvc_load(struct altsvcinfo *asi, const char *file)
 {
   CURLcode result = CURLE_OK;
   char *line = NULL;
-  FILE *fp = fopen(file, FOPEN_READTEXT);
+  FILE *fp;
+
+  /* we need a private copy of the file name so that the altsvc cache file
+     name survives an easy handle reset */
+  free(asi->filename);
+  asi->filename = strdup(file);
+  if(!asi->filename)
+    return CURLE_OUT_OF_MEMORY;
+
+  fp = fopen(file, FOPEN_READTEXT);
   if(fp) {
     line = malloc(MAX_ALTSVC_LINE);
     if(!line)
@@ -206,6 +215,7 @@ static CURLcode altsvc_load(struct altsvcinfo *asi, const char *file)
   return result;
 
   fail:
+  Curl_safefree(asi->filename);
   free(line);
   fclose(fp);
   return CURLE_OUT_OF_MEMORY;
@@ -299,6 +309,7 @@ void Curl_altsvc_cleanup(struct altsvcinfo *altsvc)
       n = e->next;
       altsvc_free(as);
     }
+    free(altsvc->filename);
     free(altsvc);
   }
 }
@@ -317,6 +328,10 @@ CURLcode Curl_altsvc_save(struct altsvcinfo *altsvc, const char *file)
     /* no cache activated */
     return CURLE_OK;
 
+  /* if not new name is given, use the one we stored from the load */
+  if(!file && altsvc->filename)
+    file = altsvc->filename;
+
   if((altsvc->flags & CURLALTSVC_READONLYFILE) || !file || !file[0])
     /* marked as read-only, no file or zero length file name */
     return CURLE_OK;