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

6 files changed, 143 insertions, 4 deletions

diff --git a/docs/libcurl/curl_easy_reset.3 b/docs/libcurl/curl_easy_reset.3
index 539f9c716..3c844c7dd 100644
--- a/docs/libcurl/curl_easy_reset.3
+++ b/docs/libcurl/curl_easy_reset.3
@@ -5,7 +5,7 @@
 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
-.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
 .\" *
 .\" * This software is licensed as described in the file COPYING, which
 .\" * you should have received as part of this distribution. The terms
@@ -33,7 +33,8 @@ default values. This puts back the handle to the same state as it was in when
 it was just created with \fIcurl_easy_init(3)\fP.
 
 It does not change the following information kept in the handle: live
-connections, the Session ID cache, the DNS cache, the cookies and shares.
+connections, the Session ID cache, the DNS cache, the cookies, the shares or
+the alt-svc cache.
 .SH AVAILABILITY
 This function was added in libcurl 7.12.1
 .SH RETURN VALUE
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;
diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 5fbe18396..be55f0460 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -192,6 +192,7 @@ test1700 test1701 test1702 \
 test1800 test1801 \
 \
 test1900 test1901 test1902 test1903 test1904 test1905 test1906 test1907 \
+test1908 \
 \
 test2000 test2001 test2002 test2003 test2004 test2005 test2006 test2007 \
 test2008 test2009 test2010 test2011 test2012 test2013 test2014 test2015 \
diff --git a/tests/data/test1908 b/tests/data/test1908
new file mode 100644
index 000000000..de34d0ee2
--- /dev/null
+++ b/tests/data/test1908
@@ -0,0 +1,71 @@
+<testcase>
+<info>
+<keywords>
+CURLINFO_EFFECTIVE_URL
+</keywords>
+</info>
+
+# Server-side
+<reply>
+<data nocheck="yes">
+HTTP/1.1 200 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Content-Type: text/html
+Funny-head: yesyes swsclose
+Content-Length: 0
+alt-svc: h2="3dbbdetxoyw4nsp6c3cc456oj2ays6s43ezxzsfxxri3h5xqd.example:443"; ma=315360000; persist=1
+
+</data>
+</reply>
+
+# Client-side
+<client>
+<server>
+http
+</server>
+
+# require debug so that alt-svc can work over plain old HTTP
+<features>
+alt-svc
+debug
+</features>
+<name>
+alt-svc cache save after resetting the handle
+</name>
+<setenv>
+# make debug-curl accept Alt-Svc over plain HTTP
+CURL_ALTSVC_HTTP="yeah"
+</setenv>
+<tool>
+lib1908
+</tool>
+
+<command>
+%HOSTIP:%HTTPPORT/1908
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<strip>
+^User-Agent:.*
+</strip>
+<protocol>
+GET /1908 HTTP/1.1

+Host: %HOSTIP:%HTTPPORT

+Accept: */*

+

+</protocol>
+<stripfile>
+# strip out the (dynamic) expire date from the file so that the rest
+# matches
+s/\"([^\"]*)\"/TIMESTAMP/
+</stripfile>
+<file name="log/altsvc-1908">
+# Your alt-svc cache. https://curl.haxx.se/docs/alt-svc.html
+# This file was generated by libcurl! Edit at your own risk.
+h1 127.0.0.1 8990 h2 3dbbdetxoyw4nsp6c3cc456oj2ays6s43ezxzsfxxri3h5xqd.example 443 TIMESTAMP 1 0
+</file>
+</verify>
+</testcase>
diff --git a/tests/libtest/Makefile.inc b/tests/libtest/Makefile.inc
index 374a66747..95ef8309b 100644
--- a/tests/libtest/Makefile.inc
+++ b/tests/libtest/Makefile.inc
@@ -33,7 +33,7 @@ noinst_PROGRAMS = chkhostname libauthretry libntlmconnect                \
  lib1550 lib1551 lib1552 lib1553 lib1554 lib1555 lib1556 lib1557 \
  lib1558 lib1559 lib1560 lib1564 lib1565 \
  lib1591 lib1592 lib1593 lib1594 lib1596 \
- lib1900 lib1905 lib1906 lib1907 \
+ lib1900 lib1905 lib1906 lib1907 lib1908 \
  lib2033
 
 chkdecimalpoint_SOURCES = chkdecimalpoint.c ../../lib/mprintf.c \
@@ -578,6 +578,10 @@ lib1907_SOURCES = lib1907.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1907_LDADD = $(TESTUTIL_LIBS)
 lib1907_CPPFLAGS = $(AM_CPPFLAGS)
 
+lib1908_SOURCES = lib1908.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
+lib1908_LDADD = $(TESTUTIL_LIBS)
+lib1908_CPPFLAGS = $(AM_CPPFLAGS)
+
 lib2033_SOURCES = libntlmconnect.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib2033_LDADD = $(TESTUTIL_LIBS)
 lib2033_CPPFLAGS = $(AM_CPPFLAGS) -DUSE_PIPELINING
diff --git a/tests/libtest/lib1908.c b/tests/libtest/lib1908.c
new file mode 100644
index 000000000..bacbc9710
--- /dev/null
+++ b/tests/libtest/lib1908.c
@@ -0,0 +1,47 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2013 - 2020, Linus Nielsen Feltzing, <linus@haxx.se>
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+#include "test.h"
+
+#include "testutil.h"
+#include "warnless.h"
+#include "memdebug.h"
+
+int test(char *URL)
+{
+  CURLcode ret = CURLE_OK;
+  CURL *hnd;
+  start_test_timing();
+
+  curl_global_init(CURL_GLOBAL_ALL);
+
+  hnd = curl_easy_init();
+  if(hnd) {
+    curl_easy_setopt(hnd, CURLOPT_URL, URL);
+    curl_easy_setopt(hnd, CURLOPT_NOPROGRESS, 1L);
+    curl_easy_setopt(hnd, CURLOPT_ALTSVC, "log/altsvc-1908");
+    ret = curl_easy_perform(hnd);
+    curl_easy_reset(hnd);
+    curl_easy_cleanup(hnd);
+  }
+  curl_global_cleanup();
+  return (int)ret;
+}