cookies: only save the cookie file if the engine is enabled

Follow-up to 8eddb8f4259.

If the cookieinfo pointer is NULL there really is nothing to save.

Without this fix, we got a problem when a handle was using shared object
with cookies and is told to "FLUSH" it to file (which worked) and then
the share object was removed and when the easy handle was closed just
afterwards it has no cookieinfo and no cookies so it decided to save an
empty jar (overwriting the file just flushed).

Test 1905 now verifies that this works.

Assisted-by: Michael Wallner
Assisted-by: Marcel Raad

Closes #3621

5 files changed, 165 insertions, 5 deletions

diff --git a/lib/cookie.c b/lib/cookie.c
index a58ce2b35..65cc11732 100644
--- a/lib/cookie.c
+++ b/lib/cookie.c
@@ -1541,9 +1541,12 @@ static int cookie_output(struct CookieInfo *c, const char *dumphere)
   unsigned int j;
   struct Cookie **array;
 
+  if(!c)
+    /* no cookie engine alive */
+    return 0;
+
   /* at first, remove expired cookies */
-  if(c)
-    remove_expired(c);
+  remove_expired(c);
 
   if(!strcmp("-", dumphere)) {
     /* use stdout */
@@ -1562,7 +1565,7 @@ static int cookie_output(struct CookieInfo *c, const char *dumphere)
         "# This file was generated by libcurl! Edit at your own risk.\n\n",
         out);
 
-  if(c && c->numcookies) {
+  if(c->numcookies) {
     array = malloc(sizeof(struct Cookie *) * c->numcookies);
     if(!array) {
       if(!use_stdout)
diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 3d13e3a27..0dcbedfe5 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -189,7 +189,7 @@ test1700 test1701 test1702 \
 \
 test1800 test1801 \
 \
-test1900 test1901 test1902 test1903 test1904 \
+test1900 test1901 test1902 test1903 test1904 test1905 \
 \
 test2000 test2001 test2002 test2003 test2004 test2005 test2006 test2007 \
 test2008 test2009 test2010 test2011 test2012 test2013 test2014 test2015 \
diff --git a/tests/data/test1905 b/tests/data/test1905
new file mode 100644
index 000000000..dac1471f5
--- /dev/null
+++ b/tests/data/test1905
@@ -0,0 +1,60 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+cookies
+FLUSH
+</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
+Set-Cookie: foobar=name;
+Set-Cookie: secondcookie=present;
+
+</data>
+</reply>
+
+# Client-side
+<client>
+<server>
+http
+</server>
+ <name>
+CURLOPT_COOKIELIST set to "FLUSH" of a shared cookie object
+ </name>
+<tool>
+lib1905
+</tool
+<command>
+http://%HOSTIP:%HTTPPORT/we/want/1905
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<strip>
+^User-Agent:.*
+</strip>
+<protocol>
+GET /we/want/1905 HTTP/1.1

+Host: %HOSTIP:%HTTPPORT

+Accept: */*

+

+</protocol>
+<file name="log/cookies1905" mode="text">
+# Netscape HTTP Cookie File
+# https://curl.haxx.se/docs/http-cookies.html
+# This file was generated by libcurl! Edit at your own risk.
+
+%HOSTIP	FALSE	/we/want/	FALSE	0	secondcookie	present
+%HOSTIP	FALSE	/we/want/	FALSE	0	foobar	name
+</file>
+</verify>
+</testcase>
diff --git a/tests/libtest/Makefile.inc b/tests/libtest/Makefile.inc
index 2e5236fad..91fd85a87 100644
--- a/tests/libtest/Makefile.inc
+++ b/tests/libtest/Makefile.inc
@@ -33,7 +33,7 @@ noinst_PROGRAMS = chkhostname libauthretry libntlmconnect                \
  lib1558 \
  lib1560 \
  lib1591 lib1592 \
- lib1900 \
+ lib1900 lib1905 \
  lib2033
 
 chkdecimalpoint_SOURCES = chkdecimalpoint.c ../../lib/mprintf.c \
@@ -535,6 +535,10 @@ lib1900_SOURCES = lib1900.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1900_LDADD = $(TESTUTIL_LIBS)
 lib1900_CPPFLAGS = $(AM_CPPFLAGS)
 
+lib1905_SOURCES = lib1905.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
+lib1905_LDADD = $(TESTUTIL_LIBS)
+lib1905_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/lib1905.c b/tests/libtest/lib1905.c
new file mode 100644
index 000000000..1d1de27e7
--- /dev/null
+++ b/tests/libtest/lib1905.c
@@ -0,0 +1,93 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2019, 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
+ * 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)
+{
+  CURLM *cm = NULL;
+  CURLSH *sh = NULL;
+  CURL *ch = NULL;
+  int unfinished;
+
+  cm = curl_multi_init();
+  if(!cm)
+    return 1;
+  sh = curl_share_init();
+  if(!sh)
+    goto cleanup;
+
+  curl_share_setopt(sh, CURLSHOPT_SHARE, CURL_LOCK_DATA_COOKIE);
+  curl_share_setopt(sh, CURLSHOPT_SHARE, CURL_LOCK_DATA_COOKIE);
+
+  ch = curl_easy_init();
+  if(!ch)
+    goto cleanup;
+
+  curl_easy_setopt(ch, CURLOPT_SHARE, sh);
+  curl_easy_setopt(ch, CURLOPT_URL, URL);
+  curl_easy_setopt(ch, CURLOPT_COOKIEFILE, "log/cookies1905");
+  curl_easy_setopt(ch, CURLOPT_COOKIEJAR, "log/cookies1905");
+
+  curl_multi_add_handle(cm, ch);
+
+  unfinished = 1;
+  while(unfinished) {
+    int MAX;
+    long max_tout;
+    fd_set R, W, E;
+    struct timeval timeout;
+
+    FD_ZERO(&R);
+    FD_ZERO(&W);
+    FD_ZERO(&E);
+    curl_multi_perform(cm, &unfinished);
+
+    curl_multi_fdset(cm, &R, &W, &E, &MAX);
+    curl_multi_timeout(cm, &max_tout);
+
+    if(max_tout > 0) {
+      timeout.tv_sec = max_tout / 1000;
+      timeout.tv_usec = (max_tout % 1000) * 1000;
+    }
+    else {
+      timeout.tv_sec = 0;
+      timeout.tv_usec = 1000;
+    }
+
+    select(MAX + 1, &R, &W, &E, &timeout);
+  }
+
+  curl_easy_setopt(ch, CURLOPT_COOKIELIST, "FLUSH");
+  curl_easy_setopt(ch, CURLOPT_SHARE, NULL);
+
+  curl_multi_remove_handle(cm, ch);
+  cleanup:
+  curl_easy_cleanup(ch);
+  curl_share_cleanup(sh);
+  curl_multi_cleanup(cm);
+
+  return 0;
+}