Clean up usage and error reporting output

- Shorten/clean up some error messages
- Usage syntax should go to stderr like most BSD programs
- Make usage syntax use a single fprintf() call
- Use warnx() instead of warn() where applicable
- Use warnx() instead of printf() in some scenarios; these messages
  will now go to stderr instead of stdout
- Reflect the above changes in the man page

bsdhwmon.8

@@ -1,4 +1,4 @@
-.Dd January 21, 2016
+.Dd December 21, 2017
 .Dt BSDHWMON 8
 .Os
 .Sh NAME
@@ -14,7 +14,7 @@ is a user-land application which communicates via SMBus with hardware
 monitoring ICs on motherboards.  Many different pieces of information
 can be returned, but the most common are fan RPMs, processor and system
 temperatures, and motherboard voltages.  All data is sent to standard
-output.
+output.  Usage syntax and all errors are sent to standard error.
 .Pp
 At this time,
 .Nm

bsdhwmon.8.txt

@@ -11,7 +11,7 @@ DESCRIPTION
      hardware monitoring ICs on motherboards.  Many different pieces of infor-
      mation can be returned, but the most common are fan RPMs, processor and
      system temperatures, and motherboard voltages.  All data is sent to stan-
-     dard output.
+     dard output.  Usage syntax and all errors are sent to standard error.
 
      At this time, bsdhwmon supports a multitude of Winbond hardware monitor-
      ing ICs, predominantly on Supermicro motherboards.
@@ -149,4 +149,4 @@ CONTRIBUTORS
      lm_sensors project, for providing an unofficial secondary source of IC
      documentation and details of chip quirks.
 
-FreeBSD 9.3                    January 21, 2016                    FreeBSD 9.3
+FreeBSD 9.3                    December 21, 2017                   FreeBSD 9.3

main.c

@@ -83,18 +83,20 @@ VERBOSE(const char *fmt, ...)
 static void
 USAGE(void)
 {
-	printf("Usage: bsdhwmon [options]\n");
-	printf("\n");
-	printf("Options:\n");
-	printf("  -J            JSON-formatted output\n");
-	printf("  -c            comma-delimited output\n");
-	printf("  -f DEVICE     use DEVICE as smb(4) device (default: " DEFAULT_SMBDEV ")\n");
-	printf("  -l            list supported motherboard ID strings\n");
-	printf("  -h            print this message\n");
-	printf("  -v            be verbose (show debugging output)\n");
-	printf("\n");
-	printf("https://github.com/koitsu/bsdhwmon\n");
-	printf("Report bugs at https://github.com/koitsu/bsdhwmon/issues\n");
+	fprintf(stderr,
+		"Usage: bsdhwmon [options]\n"
+		"\n"
+		"Options:\n"
+		"  -J            JSON-formatted output\n"
+		"  -c            comma-delimited output\n"
+		"  -f DEVICE     use DEVICE as smb(4) device (default: " DEFAULT_SMBDEV ")\n"
+		"  -l            list supported motherboard ID strings\n"
+		"  -h            print this message\n"
+		"  -v            be verbose (show debugging output)\n"
+		"\n"
+		"https://github.com/koitsu/bsdhwmon\n"
+		"Report bugs at https://github.com/koitsu/bsdhwmon/issues\n"
+	);
 	exit(EX_USAGE);
 }
 
@@ -129,7 +131,7 @@ main(int argc, char *argv[])
 				break;
 			case 'f':
 				if (strlcpy(smbdev, optarg, MAXPATHLEN) >= MAXPATHLEN) {
-					warn("Device pathname exceeds %u bytes in length", MAXPATHLEN);
+					warnx("Device pathname exceeds %u bytes in length", MAXPATHLEN);
 					exitcode = EX_SOFTWARE;
 					goto finish;
 				}
@@ -154,7 +156,7 @@ main(int argc, char *argv[])
 	 * bsdhwmon requires root access due to opening /dev/smbX
 	 */
 	if (geteuid() != 0) {
-		warn("Must be run as root, or setuid root");
+		warnx("Must be run as root, or setuid root");
 		exitcode = EX_NOPERM;
 		goto finish;
 	}
@@ -163,7 +165,7 @@ main(int argc, char *argv[])
 	 * Do some basic argument conflict checking
 	 */
 	if (comma_output && json_output) {
-		warn("Please choose only one output format");
+		warnx("Please choose only one output format");
 		exitcode = EX_USAGE;
 		goto finish;
 	}
@@ -202,7 +204,7 @@ main(int argc, char *argv[])
 	}
 
 	if ((mb = board_lookup(maker, product)) == NULL) {
-		printf("Your motherboard does not appear to be supported.  Please visit\n"
+		warnx("Your motherboard does not appear to be supported.  Please visit\n"
 		     "https://github.com/koitsu/bsdhwmon to see if support for your motherboard\n"
 		     "and/or system is under development.\n");
 		exitcode = EX_DATAERR;
@@ -244,8 +246,7 @@ main(int argc, char *argv[])
 			ret = w83793g_main(smbfd, mb->slave, sdata);
 			break;
 		default:
-			printf("Internal bsdhwmon coding error.  Please report this bug\n"
-			     "to the bsdhwmon author.\n");
+			warnx("Internal error.  Please report this bug to the author.");
 			exitcode = EX_SOFTWARE;
 			goto finish;
 	}
@@ -255,9 +256,9 @@ main(int argc, char *argv[])
 	 * validation passed, etc.).
 	 */
 	if (ret != 0) {
-		printf("Your motherboard is supported, but H/W chip verification failed.\n"
+		warnx("Your motherboard is supported, but H/W chip verification failed.\n"
 		     "Please re-run bsdhwmon with the -v flag and send full output + bug\n"
-		     "report to the bsdhwmon author.\n");
+		     "report to the author.");
 		exitcode = EX_SOFTWARE;
 		goto finish;
 	}