nldev

commit b9f67568d14c2dead805172f0d42ad6c9f98cdf2
parent e0713f648e6bc486632c261e29d36c052c54f381
Author: Platon Ryzhikov <ihummer63@yandex.ru>
Date:   Sat, 11 Sep 2021 15:24:27 +0300

if neither subsystem nor runpath is specified, process uevents based on compiled-in config

Signed-off-by: Christoph Lohmann <20h@r-36.net>

Diffstat:
Makefile
 | 
7
+++++--
config.def.h
 | 
5
+++++
nldev.8
 | 
6
+++++-
nldev.c
 | 
32
++++++++++++++++++++++++++++++--

4 files changed, 45 insertions(+), 5 deletions(-)
diff --git a/Makefile b/Makefile
@@ -18,7 +18,10 @@ options:
 	@echo CC $<
 	@${CC} -c ${CFLAGS} $<
 
-${OBJ}: config.mk
+${OBJ}: config.h config.mk
+
+config.h:
+	cp config.def.h $@
 
 ${NAME}: ${OBJ}
 	@echo CC -o $@
@@ -31,7 +34,7 @@ clean:
 dist: clean
 	@echo creating dist tarball
 	@mkdir -p ${NAME}-${VERSION}
-	@cp -R LICENSE Makefile README.md FIXES.md config.mk \
+	@cp -R LICENSE Makefile README.md FIXES.md config.def.h config.mk \
 		${SRC} ${NAME}.8 *.h ${NAME}-${VERSION}
 	@tar -cf ${NAME}-${VERSION}.tar ${NAME}-${VERSION}
 	@gzip ${NAME}-${VERSION}.tar
diff --git a/config.def.h b/config.def.h
@@ -0,0 +1,5 @@
+static const Rule rules[] = {
+	/* ACTION    SUBSYSTEM      other env variables   command to run */
+	{  "add",    NULL,          "DEVNAME",            "/bin/mdev" },
+	{  "remove", NULL,          "DEVNAME",            "/bin/mdev" },
+};
diff --git a/nldev.8 b/nldev.8
@@ -42,7 +42,8 @@ Turn on debug messages. This will not work in conjunction with
 .
 .It Fl f Ar subsystem
 This option will filter for the subsystem key in a netlink message
-and compare it to the subsystem string.
+and compare it to the subsystem string. On success runpath helper
+will be run.
 .
 .It Fl h
 Show usage.
@@ -58,6 +59,9 @@ Only show netlink messages from libudev.
 This option specifies the runpath for the helper that is launched
 on every received netlink event (default: /bin/mdev).
 .El
+
+If neither subsystem nor runpath is specified, uevents are processed
+based on compiled-in config.
 .
 .Sh AUTHORS
 See the LICENSE file for the authors of this software.
diff --git a/nldev.c b/nldev.c
@@ -21,7 +21,17 @@
 #include <linux/types.h>
 #include <linux/netlink.h>
 
+typedef struct {
+	const char *action; /* ACTION to run rule for */
+	const char *subsystem; /* SUBSYSTEM to run the rule for, NULL for any */
+	const char *envvar; /* other environment variable to run rule for, NULL for any */
+	const char *runpath;
+} Rule;
+
 #include "arg.h"
+#include "config.h"
+
+#define LENGTH(X)               (sizeof X / sizeof X[0])
 
 char *argv0;
 int listfd = -1;
@@ -199,7 +209,7 @@ main(int argc, char *argv[])
 	showkernel = 1;
 	showudev = 1;
 	subsystem = NULL;
-	runpath = "/bin/mdev";
+	runpath = NULL;
 
 	ARGBEGIN {
 	case 'b':
@@ -210,6 +220,8 @@ main(int argc, char *argv[])
 		break;
 	case 'f':
 		subsystem = EARGF(usage());
+		if (!runpath)
+			runpath = "/bin/mdev";
 		break;
 	case 'k':
 		showudev = 0;
@@ -324,7 +336,23 @@ main(int argc, char *argv[])
 				getenv("DEVPATH") != NULL &&
 				getenv("SUBSYSTEM") != NULL &&
 				getenv("SEQNUM") != NULL) {
-			child(runpath);
+			if (runpath)
+				child(runpath);
+			else {
+				for (i = 0; i < LENGTH(rules); i+=1) {
+					if (rules[i].action == NULL || rules[i].runpath == NULL) /* rule must have non-NULL action and runpath */
+						continue;
+					if (strcmp(getenv("ACTION"), rules[i].action))
+						continue;
+					if (rules[i].subsystem != NULL)
+						if (strcmp(getenv("SUBSYSTEM"), rules[i].subsystem))
+							continue;
+					if (rules[i].envvar != NULL)
+						if (getenv(rules[i].envvar) == NULL)
+							continue;
+					child(rules[i].runpath);
+				}
+			}
 		}
 	}