On 1.8.x branch: Merge r1808456 from trunk:

  Win32: Don't seek to the end when opening files with APR_FOPEN_APPEND.

git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.8.x@1902377 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 54 insertions, 1 deletions

diff --git a/CHANGES b/CHANGES
index 1e614b628..675365611 100644
--- a/CHANGES
+++ b/CHANGES
@@ -20,6 +20,9 @@ Changes for APR 1.8.0
   *) apr_file_gets: Optimize for buffered files on Windows.
      [Evgeny Kotkov <evgeny.kotkov visualsvn.com>]
 
+  *) Don't seek to the end when opening files with APR_FOPEN_APPEND on Windows.
+     [Evgeny Kotkov <evgeny.kotkov visualsvn.com>]
+
 Changes for APR 1.7.1
 
   *) SECURITY: CVE-2021-35940 (cve.mitre.org)
diff --git a/file_io/win32/open.c b/file_io/win32/open.c
index 3c00bfc79..f1a46286d 100644
--- a/file_io/win32/open.c
+++ b/file_io/win32/open.c
@@ -445,7 +445,6 @@ APR_DECLARE(apr_status_t) apr_file_open(apr_file_t **new, const char *fname,
 
     if (flag & APR_FOPEN_APPEND) {
         (*new)->append = 1;
-        SetFilePointer((*new)->filehand, 0, NULL, FILE_END);
     }
     if (flag & APR_FOPEN_BUFFERED) {
         (*new)->buffered = 1;
diff --git a/test/testfile.c b/test/testfile.c
index 9419b0a7c..9087b04f8 100644
--- a/test/testfile.c
+++ b/test/testfile.c
@@ -1711,6 +1711,56 @@ static void test_append_locked(abts_case *tc, void *data)
     apr_file_remove(fname, p);
 }
 
+static void test_append_read(abts_case *tc, void *data)
+{
+    apr_status_t rv;
+    apr_file_t *f;
+    const char *fname = "data/testappend_read.dat";
+    apr_off_t offset;
+    char buf[64];
+
+    apr_file_remove(fname, p);
+
+    /* Create file with contents. */
+    rv = apr_file_open(&f, fname, APR_FOPEN_WRITE | APR_FOPEN_CREATE,
+                       APR_FPROT_OS_DEFAULT, p);
+    APR_ASSERT_SUCCESS(tc, "create file", rv);
+
+    rv = apr_file_puts("abc", f);
+    APR_ASSERT_SUCCESS(tc, "write to file", rv);
+    apr_file_close(f);
+
+    /* Re-open it with APR_FOPEN_APPEND. */
+    rv = apr_file_open(&f, fname,
+                       APR_FOPEN_READ | APR_FOPEN_WRITE | APR_FOPEN_APPEND,
+                       APR_FPROT_OS_DEFAULT, p);
+    APR_ASSERT_SUCCESS(tc, "open file", rv);
+
+    /* Test the initial file offset.  Even though we used APR_FOPEN_APPEND,
+     * the offset should be kept in the beginning of the file until the
+     * first append.  (Previously, the Windows implementation performed
+     * an erroneous seek to the file's end right after opening it.)
+     */
+    offset = 0;
+    rv = apr_file_seek(f, APR_CUR, &offset);
+    APR_ASSERT_SUCCESS(tc, "get file offset", rv);
+    ABTS_INT_EQUAL(tc, 0, (int)offset);
+
+    /* Test reading from the file. */
+    rv = apr_file_gets(buf, sizeof(buf), f);
+    APR_ASSERT_SUCCESS(tc, "read from file", rv);
+    ABTS_STR_EQUAL(tc, "abc", buf);
+
+    /* Test the file offset after reading. */
+    offset = 0;
+    rv = apr_file_seek(f, APR_CUR, &offset);
+    APR_ASSERT_SUCCESS(tc, "get file offset", rv);
+    ABTS_INT_EQUAL(tc, 3, (int)offset);
+
+    apr_file_close(f);
+    apr_file_remove(fname, p);
+}
+
 abts_suite *testfile(abts_suite *suite)
 {
     suite = ADD_SUITE(suite)
@@ -1765,6 +1815,7 @@ abts_suite *testfile(abts_suite *suite)
     abts_run_test(suite, test_datasync_on_stream, NULL);
     abts_run_test(suite, test_atomic_append, NULL);
     abts_run_test(suite, test_append_locked, NULL);
+    abts_run_test(suite, test_append_read, NULL);
 
     return suite;
 }