ionice: add the way to specify the target processes with pgid and uid

ioprio_get and ioprio_set system call accept not only process ID but
also process group ID(pgid) and user ID(uid) to specify the target
process(es).  However, ionice command accepts only process ID.  With
this patch a user can specify the target processes with pgid(-P
option) and uid(-u option).

[kzak@redhat.com: - tiny cleanup in usage()]

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

1 files changed, 48 insertions, 22 deletions

diff --git a/schedutils/ionice.c b/schedutils/ionice.c
index 50616dfc6..a3edf5512 100644
--- a/schedutils/ionice.c
+++ b/schedutils/ionice.c
@@ -68,9 +68,9 @@ static int parse_ioclass(const char *str)
 	return -1;
 }
 
-static void ioprio_print(int pid)
+static void ioprio_print(int pid, int who)
 {
-	int ioprio = ioprio_get(IOPRIO_WHO_PROCESS, pid);
+	int ioprio = ioprio_get(who, pid);
 
 	if (ioprio == -1)
 		err(EXIT_FAILURE, _("ioprio_get failed"));
@@ -89,9 +89,9 @@ static void ioprio_print(int pid)
 	}
 }
 
-static void ioprio_setpid(pid_t pid, int ioclass, int data)
+static void ioprio_setid(int which, int ioclass, int data, int who)
 {
-	int rc = ioprio_set(IOPRIO_WHO_PROCESS, pid,
+	int rc = ioprio_set(who, which,
 			    IOPRIO_PRIO_VALUE(ioclass, data));
 
 	if (rc == -1 && !tolerant)
@@ -106,6 +106,8 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out)
 		 "\n"
 		 "Usage:\n"
 		 "  %1$s [OPTION] -p PID [PID...]\n"
+		 "  %1$s [OPTION] -P PGID [PGID...]\n"
+		 "  %1$s [OPTION] -u UID [UID...]\n"
 		 "  %1$s [OPTION] COMMAND\n"
 		 "\n"
 		 "Options:\n"
@@ -113,8 +115,10 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out)
 		 "                           0: none, 1: realtime, 2: best-effort, 3: idle\n"
 		 "  -n, --classdata <num> scheduling class data\n"
 		 "                           0-7 for realtime and best-effort classes\n"
-		 "  -p, --pid=PID         view or modify already running process\n"
+		 "  -p, --pid <pid>       view or modify already running process\n"
+		 "  -P, --pgid <pgrp>     view or modify already running process group\n"
 		 "  -t, --ignore          ignore failures\n"
+		 "  -u, --uid <uid>       view or modify already running processes owned by a user\n"
 		 "  -V, --version         output version information and exit\n"
 		 "  -h, --help            display this help and exit\n\n"),
 		program_invocation_short_name);
@@ -125,7 +129,8 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out)
 int main(int argc, char **argv)
 {
 	int data = 4, set = 0, ioclass = IOPRIO_CLASS_BE, c;
-	pid_t pid = 0;
+	int which = 0, who = 0;
+	const char *invalid_msg = NULL;
 
 	static const struct option longopts[] = {
 		{ "classdata", required_argument, NULL, 'n' },
@@ -133,6 +138,8 @@ int main(int argc, char **argv)
 		{ "help",      no_argument,       NULL, 'h' },
 		{ "ignore",    no_argument,       NULL, 't' },
 		{ "pid",       required_argument, NULL, 'p' },
+		{ "pgid",      required_argument, NULL, 'P' },
+		{ "uid",       required_argument, NULL, 'u' },
 		{ "version",   no_argument,       NULL, 'V' },
 		{ NULL, 0, NULL, 0 }
 	};
@@ -142,7 +149,7 @@ int main(int argc, char **argv)
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	while ((c = getopt_long(argc, argv, "+n:c:p:tVh", longopts, NULL)) != EOF)
+	while ((c = getopt_long(argc, argv, "+n:c:p:P:u:tVh", longopts, NULL)) != EOF)
 		switch (c) {
 		case 'n':
 			data = strtos32_or_err(optarg, _("invalid class data argument"));
@@ -162,7 +169,27 @@ int main(int argc, char **argv)
 			set |= 2;
 			break;
 		case 'p':
-			pid = strtos32_or_err(optarg, _("invalid PID argument"));
+			if (who)
+				errx(EXIT_FAILURE,
+				     _("can handle one of pid, pgid or uid at once"));
+			invalid_msg = _("invalid PID argument");
+			which = strtos32_or_err(optarg, invalid_msg);
+			who = IOPRIO_WHO_PROCESS;
+			break;
+		case 'P':
+			if (who)
+				errx(EXIT_FAILURE,
+				     _("can handle one of pid, pgid or uid at once"));
+			invalid_msg = _("invalid PGID argument");
+			which = strtos32_or_err(optarg, invalid_msg);
+			who = IOPRIO_WHO_PGRP;
+			break;
+		case 'u':
+			if (who)
+				errx(EXIT_FAILURE,
+				     _("can handle one of pid, pgid or uid at once"));
+			which = strtos32_or_err(optarg, invalid_msg);
+			who = IOPRIO_WHO_USER;
 			break;
 		case 't':
 			tolerant = 1;
@@ -197,37 +224,36 @@ int main(int argc, char **argv)
 			break;
 	}
 
-	if (!set && !pid && optind == argc)
+	if (!set && !which && optind == argc)
 		/*
 		 * ionice without options, print the current ioprio
 		 */
-		ioprio_print(0);
-
-	else if (!set && pid) {
+		ioprio_print(0, IOPRIO_WHO_PROCESS);
+	else if (!set && who) {
 		/*
-		 * ionice -p PID [PID ...]
+		 * ionice -p|-P|-u ID [ID ...]
 		 */
-		ioprio_print(pid);
+		ioprio_print(which, who);
 
 		for(; argv[optind]; ++optind) {
-			pid = strtos32_or_err(argv[optind], _("invalid PID argument"));
-			ioprio_print(pid);
+			which = strtos32_or_err(argv[optind], invalid_msg);
+			ioprio_print(which, who);
 		}
-	} else if (set && pid) {
+	} else if (set && who) {
 		/*
-		 * ionice -c CLASS -p PID [PID ...]
+		 * ionice -c CLASS -p|-P|-u ID [ID ...]
 		 */
-		ioprio_setpid(pid, ioclass, data);
+		ioprio_setid(which, ioclass, data, who);
 
 		for(; argv[optind]; ++optind) {
-			pid = strtos32_or_err(argv[optind], _("invalid PID argument"));
-			ioprio_setpid(pid, ioclass, data);
+			which = strtos32_or_err(argv[optind], invalid_msg);
+			ioprio_setid(which, ioclass, data, who);
 		}
 	} else if (argv[optind]) {
 		/*
 		 * ionice [-c CLASS] COMMAND
 		 */
-		ioprio_setpid(0, ioclass, data);
+		ioprio_setid(0, ioclass, data, IOPRIO_WHO_PROCESS);
 		execvp(argv[optind], &argv[optind]);
 		err(EXIT_FAILURE, _("failed to execute %s"), argv[optind]);
 	} else