test and update the printf functionality

Signed-off-by: Ava Hahn <ava@aidanis.online>

Makefile

@@ -20,7 +20,7 @@ ALOG_LIB = $(TARGET_DIR)/alog.so
 include $(dir $(lastword $(MAKEFILE_LIST)))tests/tests.mk
 
 .PHONY: alog-so
-alog-so: $(if $(shell stat $(ALOG_LIB)), clean) $(ALOG_LIB)
+alog-so: $(if $(shell stat $(ALOG_LIB)), alog-clean) $(ALOG_LIB)
 
 $(ALOG_LIB): $(TARGET_DIR) $(ALOG_OBJ)
 	$(CC) $(LDFLAGS) -o $(ALOG_LIB) $(ALOG_OBJ)

alog.c

@@ -144,20 +144,19 @@ void alog_remove_target(int fd) {
 
 // TODO: use preprocessor directives to gate off the posix timestamp stuff
 // unless the right variable is passed in at compile time
-void alog (
+int _alog (
   alog_sev severity,
   const char * message,
-  ...
+  va_list fmt
 ) {
-  TEST_ALOG_STATE();
   if (severity == DEBUG &&
       !ALOG_LOGGING_STATE->log_debug_messages) {
     // nop :)
-    return;
+    return -1;
   }
 
   va_list fmt_list;
-  va_start(fmt_list, message);
+  va_copy(fmt_list, fmt);
 
   char *buffer;
   int size;
@@ -177,8 +176,8 @@ void alog (
 
     // TODO: Why even use msg_and_timestamp if I am going to write it wholesale into buffer?
     size = vsnprintf(NULL, 0, msg_and_timestamp, fmt_list);
-    va_start(fmt_list, message);
     va_end(fmt_list);
+    va_copy(fmt_list, fmt);
     buffer = malloc(size + 1);
     vsprintf(buffer, msg_and_timestamp, fmt_list);
     va_end(fmt_list);
@@ -187,14 +186,18 @@ void alog (
   // if severity is PRINT we avoid timestamp
   } else {
     size = vsnprintf(NULL, 0, message, fmt_list);
-    va_start(fmt_list, message);
+    va_end(fmt_list);
+    va_copy(fmt_list, fmt);
     buffer = malloc(size + 1);
     vsprintf(buffer, message, fmt_list);
     va_end(fmt_list);
   }
 
+  int written = 0;
   for (int i = 0; i < _alog_num_out_fds; i++) {
-    if (write(_alog_out_fds[i], buffer, size) < size) {
+    int num = write(_alog_out_fds[i], buffer, size);
+    written += num;
+    if (num < size) {
       // TODO: how to handle? probably cant log another message lmao
       // perhaps it should be yanked from the list? maybe not?
       ;;
@@ -204,7 +207,9 @@ void alog (
 
   if (severity == ERROR) {
     for (int i = 0; i < _alog_num_err_fds; i++) {
-      if (write(_alog_err_fds[i], buffer, size) < size) {
+      int num = write(_alog_err_fds[i], buffer, size);
+      written += num;
+      if (num < size) {
         // TODO: see above
         ;;
       }
@@ -213,19 +218,31 @@ void alog (
   }
 
   free(buffer);
+  return written;
 }
 
+int alog (
+  alog_sev severity,
+  const char * message,
+  ...
+) {
+  TEST_ALOG_STATE();
+  va_list fmt_list;
+  va_start(fmt_list, message);
+  int res = _alog(severity, message, fmt_list);
+  va_end(fmt_list);
+  return res;
+}
+
+
 #ifdef ALOG_HIJACK_PRINTF
 int printf(const char *format, ...) {
   TEST_ALOG_STATE();
   va_list fmt_list;
   va_start(fmt_list, format);
-  /* TODO: this is a duplicate call given the implementation of alog.
-   * Lets figure out a better way to handle this */
-  int size = snprintf(NULL, 0, format, fmt_list);
-  alog(PRINT, NULL, format, fmt_list);
+  int i = _alog(PRINT, format, fmt_list);
   va_end(fmt_list);
-  return size;
+  return i;
   /* potentially accept a mem leak at end of program for alog state.
    * That is, if the program using this is not already using alog correctly
    * or if ALOG has been LD_PRELOAD'ed into a program to override its printf */

alog.h

@@ -78,8 +78,9 @@ void alog_add_target(int, char);
 /* removes an fd from both out fds and err fds */
 void alog_remove_target(int);
 
-/* call to log a message. Takes a severity, a message, and format stuff */
-void alog(alog_sev, const char *, ...);
+/* call to log a message. Takes a severity, a message, and format stuff
+ * returns number of bytes written*/
+int alog(alog_sev, const char *, ...);
 
 /* overrides all calls to printf with a call to alog */
 #ifdef ALOG_HIJACK_PRINTF