i#2006 generalize drcachesim: add DRX_FILE_SKIP_OPEN for skip file open

Adds DRX_FILE_SKIP_OPEN so that drx_open_unique_file/drx_open_unique_appid_file
can skip the file open and return the resulting file name string only.

Adds test for using DRX_FILE_SKIP_OPEN.

Review-URL: https://codereview.appspot.com/311960043

api/docs/release.dox

@@ -157,6 +157,7 @@ Further non-compatibility-affecting changes include:
    modules for post-processing and across library reloads.  This is part of
    the \p drcovlib Extension.  See #drmodtrack_init() and related functions.
  - Added drx_open_unique_appid_dir().
+ - Added #DRX_FILE_SKIP_OPEN.
  - Added %[] support to dr_sscanf.
  - Added dr_map_executable_file() and dr_unmap_executable_file().
  - Added dr_get_microseconds().

ext/drx/drx.c

@@ -1304,17 +1304,21 @@ drx_open_unique_file(const char *dir, const char *prefix, const char *suffix,
                      uint extra_flags, char *result OUT, size_t result_len)
 {
     char buf[MAXIMUM_PATH];
-    file_t f;
+    file_t f = INVALID_FILE;
     int i;
     ssize_t len;
     for (i = 0; i < 10000; i++) {
         len = dr_snprintf(buf, BUFFER_SIZE_ELEMENTS(buf),
-                          "%s%c%s.%04d.%s", dir, DIRSEP, prefix, i, suffix);
+                          "%s%c%s.%04d.%s", dir, DIRSEP, prefix,
+                          (extra_flags == DRX_FILE_SKIP_OPEN) ?
+                          dr_get_random_value(9999) : i,
+                          suffix);
         if (len < 0)
-            return false;
+            return INVALID_FILE;
         NULL_TERMINATE_BUFFER(buf);
-        f = dr_open_file(buf, DR_FILE_WRITE_REQUIRE_NEW | extra_flags);
-        if (f != INVALID_FILE) {
+        if (extra_flags != DRX_FILE_SKIP_OPEN)
+            f = dr_open_file(buf, DR_FILE_WRITE_REQUIRE_NEW | extra_flags);
+        if (f != INVALID_FILE || extra_flags == DRX_FILE_SKIP_OPEN) {
             if (result != NULL)
                 dr_snprintf(result, result_len, "%s", buf);
             return f;

ext/drx/drx.h

@@ -219,17 +219,31 @@ drx_register_soft_kills(bool (*event_cb)(process_id_t pid, int exit_code));
  * LOGGING
  */
 
+/**
+ * Flag for use with drx_open_unique_file() or drx_open_unique_appid_file()
+ * in \p extra_flags to skip the file open and get the path string only.
+ *
+ * \note This flag value must not conflict with any DR_FILE_* flag value
+ * used by dr_open_file().
+ */
+#define DRX_FILE_SKIP_OPEN  0x8000
+
 DR_EXPORT
 /**
  * Opens a new file with a name constructed from "dir/prefix.xxxx.suffix",
  * where xxxx is a 4-digit number incremented until a unique name is found
  * that does not collide with any existing file.
  *
- * Passes \p extra_flags through to the dr_open_file() call.
+ * Passes \p extra_flags through to the dr_open_file() call if \p extra_flags
+ * is not DRX_FILE_SKIP_OPEN.
  *
  * On success, returns the file handle and optionally the resulting path
  * in \p result.  On failure, returns INVALID_FILE.
  *
+ * Skips dr_open_file() if \p extra_flags is DRX_FILE_SKIP_OPEN.
+ * Returns INVALID_FILE and optionally the resulting path in \p result.
+ * Unique name is not guaranteed and xxxx is set randomly.
+ *
  * \note May be called without calling drx_init().
  */
 file_t
@@ -244,11 +258,16 @@ DR_EXPORT
  * from dr_get_application_name().  The id portion of the string is from \p id,
  * which is meant to be either the process id or the thread id.
  *
- * Passes \p extra_flags through to the dr_open_file() call.
+ * Passes \p extra_flags through to the dr_open_file() call if \p extra_flags
+ * is not DRX_FILE_SKIP_OPEN.
  *
  * On success, returns the file handle and optionally the resulting path
  * in \p result.  On failure, returns INVALID_FILE.
  *
+ * Skips dr_open_file() if \p extra_flags is DRX_FILE_SKIP_OPEN.
+ * Returns INVALID_FILE and optionally the resulting path in \p result.
+ * Unique name is not guaranteed and xxxx is set randomly.
+ *
  * \note May be called without calling drx_init().
  */
 file_t

suite/tests/client-interface/drx-test.dll.c

@@ -36,6 +36,7 @@
 #include "dr_api.h"
 #include "drx.h"
 #include "client_tools.h"
+#include "string.h"
 
 #define CHECK(x, msg) do {               \
     if (!(x)) {                          \
@@ -113,6 +114,12 @@ test_unique_files(void)
     NULL_TERMINATE_BUFFER(cwd);
 #endif
 
+    f = drx_open_unique_file(cwd, "drx-test", "log",
+                             DRX_FILE_SKIP_OPEN,
+                             buf, BUFFER_SIZE_ELEMENTS(buf));
+    CHECK(f == INVALID_FILE, "drx_open_unique_file should skip file open");
+    CHECK(strstr(buf, "drx-test.") != NULL,
+          "drx_open_unique_file fail to return path string");
     f = drx_open_unique_file(cwd, "drx-test", "log",
                              0, buf, BUFFER_SIZE_ELEMENTS(buf));
     CHECK(f != INVALID_FILE, "drx_open_unique_file failed");
@@ -121,6 +128,13 @@ test_unique_files(void)
     res = dr_delete_file(buf);
     CHECK(res, "drx_open_unique_file failed");
 
+    f = drx_open_unique_appid_file(cwd, 1234, "drx-test", "txt",
+                                   DRX_FILE_SKIP_OPEN,
+                                   buf, BUFFER_SIZE_ELEMENTS(buf));
+    CHECK(f == INVALID_FILE, "drx_open_unique_appid_file should skip file open");
+    CHECK(strstr(buf,
+                 "drx-test.client.drx-test.") != NULL,
+          "drx_open_unique_appid_file fail to return path string");
     f = drx_open_unique_appid_file(cwd, dr_get_process_id(), "drx-test", "txt",
                                    0, buf, BUFFER_SIZE_ELEMENTS(buf));
     CHECK(f != INVALID_FILE, "drx_open_unique_appid_file failed");