ionice: add strtol() checks, cleanup usage text and man page

 * cleanup usage() output

 * check strtol(); don't ignore wrong command line options

The original ionice design was a little broken, because it was
possible to specify a PID and also a COMMAND:

	ionice -c2 -p 123 /bin/foo

but the command /bin/foo was executed without requested scheduling
class. That's stupid behaviour.

Now you have to use "-p PID" **or** COMMAND, but not both. Nothing is
ignored and all options are checked.

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 40 insertions, 18 deletions

diff --git a/schedutils/ionice.c b/schedutils/ionice.c
index 2331bec4f..d41a8fad4 100644
--- a/schedutils/ionice.c
+++ b/schedutils/ionice.c
@@ -78,22 +78,45 @@ static void ioprio_setpid(pid_t pid, int ioprio, int ioclass)
 static void usage(int rc)
 {
 	fprintf(stdout, _(
-	"\nionice - sets or gets process io scheduling class and priority.\n\n"
-	"Usage: ionice [OPTIONS] [COMMAND [ARG]...]\n\n"
+	"\nionice - sets or gets process io scheduling class and priority.\n"
+	"\nUsage:\n"
+	"  ionice [ options ] -p <pid> [<pid> ...]\n"
+	"  ionoce [ options ] <command> [<arg> ...]\n"
+	"\nOptions:\n"
 	"  -n <classdata>      class data (0-7, lower being higher prio)\n"
 	"  -c <class>          scheduling class\n"
 	"                      1: realtime, 2: best-effort, 3: idle\n"
-	"  -p <pid>            process pid\n"
-	"  -t                  ignore failures, run command unconditionally\n"
+	"  -t                  ignore failures\n"
 	"  -h                  this help\n\n"));
-
 	exit(rc);
 }
 
+static long getnum(const char *str)
+{
+	long num;
+	char *end = NULL;
+
+	if (str == NULL || *str == '\0')
+		goto err;
+	errno = 0;
+	num = strtol(str, &end, 10);
+
+	if (errno || (end && *end))
+		goto err;
+
+	return num;
+err:
+	if (errno)
+		err(EXIT_SUCCESS, _("cannot parse number '%s'"), str);
+	else
+		errx(EXIT_SUCCESS, _("cannot parse number '%s'"), str);
+	return 0;
+}
+
 int main(int argc, char *argv[])
 {
-	int ioprio = 4, set = 0, ioclass = IOPRIO_CLASS_BE;
-	int c, pid = 0;
+	int ioprio = 4, set = 0, ioclass = IOPRIO_CLASS_BE, c;
+	pid_t pid = 0;
 
 	setlocale(LC_ALL, "");
 	bindtextdomain(PACKAGE, LOCALEDIR);
@@ -102,15 +125,15 @@ int main(int argc, char *argv[])
 	while ((c = getopt(argc, argv, "+n:c:p:th")) != EOF) {
 		switch (c) {
 		case 'n':
-			ioprio = strtol(optarg, NULL, 10);
+			ioprio = getnum(optarg);
 			set |= 1;
 			break;
 		case 'c':
-			ioclass = strtol(optarg, NULL, 10);
+			ioclass = getnum(optarg);
 			set |= 2;
 			break;
 		case 'p':
-			pid = strtol(optarg, NULL, 10);
+			pid = getnum(optarg);
 			break;
 		case 't':
 			tolerant = 1;
@@ -142,7 +165,7 @@ int main(int argc, char *argv[])
 		ioprio_print(pid);
 
 		for(; argv[optind]; ++optind) {
-			pid = strtol(argv[optind], NULL, 10);
+			pid = getnum(argv[optind]);
 			ioprio_print(pid);
 		}
 	} else {
@@ -151,16 +174,15 @@ int main(int argc, char *argv[])
 
 			for(; argv[optind]; ++optind)
 			{
-				pid = strtol(argv[optind], NULL, 10);
+				pid = getnum(argv[optind]);
 				ioprio_setpid(pid, ioprio, ioclass);
 			}
-		} else {
+		}
+		else if (argv[optind]) {
 			ioprio_setpid(0, ioprio, ioclass);
-			if (argv[optind]) {
-				execvp(argv[optind], &argv[optind]);
-				/* execvp should never return */
-				err(EXIT_FAILURE, _("execvp failed"));
-			}
+			execvp(argv[optind], &argv[optind]);
+			/* execvp should never return */
+			err(EXIT_FAILURE, _("execvp failed"));
 		}
 	}