Add dr_vfprintf (#2823)

Adds a new API routine dr_vfprintf(). Adds a sanity check test.
DynamoRIO · Feb 10, 2018 · cb09eec · cb09eec
1 parent 761e88e
commit cb09eec
Show file tree

Hide file tree

Showing 5 changed files with 51 additions and 4 deletions.
diff --git a/api/docs/release.dox b/api/docs/release.dox
@@ -227,6 +227,7 @@ Further non-compatibility-affecting changes include:
  - Added hashtable_apply_to_all_payloads() to iterate over all payloads in a
    hashtable.
  - Added drutil_insert_get_mem_addr_ex().
+ - Added dr_vfprintf().
 
 **************************************************
 <hr>

diff --git a/core/lib/instrument.c b/core/lib/instrument.c
@@ -4547,11 +4547,9 @@ dr_printf(const char *fmt, ...)
 }
 
 DR_API ssize_t
-dr_fprintf(file_t f, const char *fmt, ...)
+dr_vfprintf(file_t f, const char *fmt, va_list ap)
 {
     ssize_t written;
-    va_list ap;
-    va_start(ap, fmt);
 #ifdef WINDOWS
     if ((f == STDOUT || f == STDERR) && print_to_console) {
         written = dr_write_to_console(f == STDOUT, fmt, ap);
@@ -4560,10 +4558,20 @@ dr_fprintf(file_t f, const char *fmt, ...)
     } else
 #endif
         written = do_file_write(f, fmt, ap);
-    va_end(ap);
     return written;
 }
 
+DR_API ssize_t
+dr_fprintf(file_t f, const char *fmt, ...)
+{
+    va_list ap;
+    ssize_t res;
+    va_start(ap, fmt);
+    res = dr_vfprintf(f, fmt, ap);
+    va_end(ap);
+    return res;
+}
+
 DR_API int
 dr_snprintf(char *buf, size_t max, const char *fmt, ...)
 {

diff --git a/core/lib/instrument_api.h b/core/lib/instrument_api.h
@@ -4149,6 +4149,13 @@ DR_API
 ssize_t
 dr_fprintf(file_t f, const char *fmt, ...);
 
+DR_API
+/**
+ * Identical to dr_fprintf() but exposes va_list.
+ */
+ssize_t
+dr_vfprintf(file_t f, const char *fmt, va_list ap);
+
 #ifdef WINDOWS
 DR_API
 /**

diff --git a/suite/tests/client-interface/file_io.dll.c b/suite/tests/client-interface/file_io.dll.c
@@ -57,6 +57,7 @@ static void test_dir(void);
 static void test_relative(void);
 static void test_map_exe(void);
 static void test_times(void);
+static void test_vfprintf(void);
 
 byte *
 find_prot_edge(const byte *start, uint prot_flag)
@@ -302,6 +303,8 @@ void dr_init(client_id_t id)
     test_map_exe();
 
     test_times();
+
+    test_vfprintf();
 }
 
 /* Creates a closed, unique temporary file and returns its filename.
@@ -491,3 +494,30 @@ test_times(void)
      */
     dr_get_time(&drtime);
 }
+
+static void
+test_vfprintf_helper(file_t f, const char *fmt, ...)
+{
+    va_list ap;
+    ssize_t len1, len2;
+
+    va_start(ap, fmt);
+    len1 = dr_vfprintf(f, fmt, ap);
+    va_end(ap);
+
+    /* check length consistency, because why not. */
+    char buf[100];
+    va_start(ap, fmt);
+    len2 = dr_vsnprintf(buf, BUFFER_SIZE_ELEMENTS(buf), fmt, ap);
+    va_end(ap);
+
+    if (len1 != len2 && !(len1 > BUFFER_SIZE_ELEMENTS(buf) && len2 == -1)) {
+        dr_fprintf(STDERR, "dr_vfprintf and dr_vsnprintf disagree.\n");
+    }
+}
+
+static void
+test_vfprintf(void)
+{
+    test_vfprintf_helper(STDERR, "vfprintf check: %d\n", 1234);
+}
diff --git a/suite/tests/client-interface/file_io.expect b/suite/tests/client-interface/file_io.expect
@@ -10,6 +10,7 @@ read_only_buf is r
 dr_safe_read() check
 DR_TRY_EXCEPT check
 dr_safe_write() check
+vfprintf check: 1234
 file separation check
 float i/o test: 3.1416
 done