os_mon: Elucidate port program error messages

Try to avoid confusion of the message 'Erlang has closed' by
clarifying that the message is sent from os_mon port programs.

3 files changed, 37 insertions, 32 deletions

diff --git a/lib/os_mon/c_src/cpu_sup.c b/lib/os_mon/c_src/cpu_sup.c
index 9c5f9a6aa5..a0432b3093 100644
--- a/lib/os_mon/c_src/cpu_sup.c
+++ b/lib/os_mon/c_src/cpu_sup.c
@@ -458,8 +458,18 @@ static void error(char* err_msg) {
    * if we get error here we have trouble,
    * silence unnecessary warnings
    */
-  if(write(FD_ERR, err_msg, strlen(err_msg)));
-  if(write(FD_ERR, "\n", 1));
+  char buffer[256] = "[os_mon] cpu supervisor port (cpu_sup): ";
+  int i = strlen(buffer), j = 0;
+  int n = strlen(err_msg);
+
+  while(i < 253 && j < n) {
+      buffer[i++] = err_msg[j++];
+  }
+  buffer[i++] = '\r';
+  buffer[i++] = '\n';
+
+  /* try to use one write only */
+  if(write(FD_ERR, buffer, i));
   exit(-1);
 }
 
diff --git a/lib/os_mon/c_src/memsup.c b/lib/os_mon/c_src/memsup.c
index 078f20ff98..593a066f98 100644
--- a/lib/os_mon/c_src/memsup.c
+++ b/lib/os_mon/c_src/memsup.c
@@ -493,7 +493,7 @@ get_basic_mem(unsigned long *tot, unsigned long *used, unsigned long *pagesize){
 #elif defined(__linux__) && !defined(_SC_AVPHYS_PAGES)
     memory_ext me;
     if (get_mem_procfs(&me) < 0) {
-        print_error("ProcFS read error.");
+        print_error("ProcFS read error");
         exit(1);
     }
     *tot      = me.total;
@@ -582,7 +582,7 @@ message_loop(int erlin_fd)
 	 *  Wait for command from Erlang
 	 */
 	if ((res = read(erlin_fd, &cmdLen, 1)) < 0) {
-	    print_error("Error reading from Erlang.");
+	    print_error("Error reading from Erlang");
 	    return;
 	}
 
@@ -603,19 +603,19 @@ message_loop(int erlin_fd)
 		  break;
 		  
 		case 0:
-		  print_error("Erlang has closed.");
+		  print_error("Erlang has closed");
 		  return;
 
 		default:
-		  print_error("Error reading from Erlang.");
+		  print_error("Error reading from Erlang");
 		  return;
 		} /* switch() */
 	    } else { /* cmdLen != 1 */
-		print_error("Invalid command length (%d) received.", cmdLen);
+		print_error("Invalid command length (%d) received", cmdLen);
 		return;
 	    }
 	} else {		/* Erlang end closed */
-	    print_error("Erlang has closed.");
+	    print_error("Erlang has closed");
 	    return;
 	}
     }
@@ -641,15 +641,12 @@ static void
 print_error(const char *format,...)
 {
   va_list args;
+  char buffer[256];
 
   va_start(args, format);
-  fprintf(stderr, "%s: ", program_name);
-  vfprintf(stderr, format, args);
+  vsnprintf(buffer, 256, format, args);
   va_end(args);
-  fprintf(stderr, " \n");
+  /* try to use one write only */
+  fprintf(stderr, "[os_mon] memory supervisor port (memsup): %s\r\n", buffer);
+  fflush(stderr);
 }
-
-
-
-
-
diff --git a/lib/os_mon/c_src/win32sysinfo.c b/lib/os_mon/c_src/win32sysinfo.c
index 2a155aae87..9d4587393f 100644
--- a/lib/os_mon/c_src/win32sysinfo.c
+++ b/lib/os_mon/c_src/win32sysinfo.c
@@ -89,6 +89,7 @@ typedef BOOL (WINAPI *tfpGetDiskFreeSpaceEx)(LPCTSTR, PULARGE_INTEGER,PULARGE_IN
 
 static  tfpGetDiskFreeSpaceEx fpGetDiskFreeSpaceEx;
 
+static void print_error(const char *msg);
 static void
 return_answer(char* value)
 {
@@ -98,7 +99,7 @@ return_answer(char* value)
 
     res = write(1,(char*) &bytes,1);
     if (res != 1) {
-	fprintf(stderr,"win32sysinfo:Error writing to pipe");
+	print_error("Error writing to pipe");
 	exit(1);
     }
 
@@ -107,9 +108,8 @@ return_answer(char* value)
     while (left > 0)
     {
 	res = write(1, value+bytes-left, left);
-	if (res <= 0)
-	{
-	    fprintf(stderr,"win32sysinfo:Error writing to pipe");
+	if (res <= 0) {
+	    print_error("Error writing to pipe");
 	    exit(1);
 	}
 	left -= res;
@@ -248,7 +248,6 @@ message_loop()
     char cmd[512];
     int res;
     
-    fprintf(stderr,"in message_loop\n");
     /* Startup ACK. */
     return_answer(OK);
     while (1)
@@ -257,12 +256,12 @@ message_loop()
 	 *  Wait for command from Erlang
 	 */
 	if ((res = read(0, &cmdLen, 1)) < 0) {
-	    fprintf(stderr,"win32sysinfo:Error reading from Erlang.");
+	    print_error("Error reading from Erlang");
 	    return;
 	}
 	
 	if (res != 1){	/* Exactly one byte read ? */ 
-	    fprintf(stderr,"win32sysinfo:Erlang has closed.");
+	    print_error("Erlang has closed");
 	    return;
 	}
 	if ((res = read(0, &cmd, cmdLen)) == cmdLen){
@@ -291,11 +290,11 @@ message_loop()
 		    return_answer("xEND");
 	}    
 	else if (res == 0) {
-	    fprintf(stderr,"win32sysinfo:Erlang has closed.");
+	    print_error("Erlang has closed");
 	    return;
 	}
 	else {
-	    fprintf(stderr,"win32sysinfo:Error reading from Erlang.");
+	    print_error("Error reading from Erlang");
 	    return;
 	} 
     }
@@ -309,10 +308,9 @@ int main(int argc, char ** argv){
     message_loop();
     return 0;    
 }
-
-
-
-
-
-
-
+static void
+print_error(const char *msg) {
+  /* try to use one write only */
+  fprintf(stderr, "[os_mon] win32 supervisor port (win32sysinfo): %s\r\n", msg);
+  fflush(stderr);
+}