libudev: device - add device lookup by subsystem:sysname

4 files changed, 179 insertions, 47 deletions

diff --git a/udev/lib/exported_symbols b/udev/lib/exported_symbols
index 2574d13e67..8e0be1ab8d 100644
--- a/udev/lib/exported_symbols
+++ b/udev/lib/exported_symbols
@@ -14,6 +14,7 @@ udev_list_entry_get_name
 udev_list_entry_get_value
 udev_device_new_from_syspath
 udev_device_new_from_devnum
+udev_device_new_from_subsystem_sysname
 udev_device_get_parent
 udev_device_get_parent_with_subsystem
 udev_device_ref
diff --git a/udev/lib/libudev-device.c b/udev/lib/libudev-device.c
index 55fcad655e..0cb992c9ea 100644
--- a/udev/lib/libudev-device.c
+++ b/udev/lib/libudev-device.c
@@ -381,6 +381,94 @@ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, de
 	return device;
 }
 
+struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
+{
+	size_t sys_path_len;
+	char path_full[UTIL_PATH_SIZE];
+	char *path;
+	struct stat statbuf;
+
+	sys_path_len = util_strlcpy(path_full, udev_get_sys_path(udev), sizeof(path_full));
+	path = &path_full[sys_path_len];
+
+	if (strcmp(subsystem, "subsystem") == 0) {
+		util_strlcpy(path, "/subsystem/", sizeof(path_full) - sys_path_len);
+		util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
+		if (stat(path_full, &statbuf) == 0)
+			goto found;
+
+		util_strlcpy(path, "/bus/", sizeof(path_full) - sys_path_len);
+		util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
+		if (stat(path_full, &statbuf) == 0)
+			goto found;
+
+		util_strlcpy(path, "/class/", sizeof(path_full) - sys_path_len);
+		util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
+		if (stat(path_full, &statbuf) == 0)
+			goto found;
+		goto out;
+	}
+
+	if (strcmp(subsystem, "module") == 0) {
+		util_strlcpy(path, "/module/", sizeof(path_full) - sys_path_len);
+		util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
+		if (stat(path_full, &statbuf) == 0)
+			goto found;
+		goto out;
+	}
+
+	if (strcmp(subsystem, "drivers") == 0) {
+		char subsys[UTIL_NAME_SIZE];
+		char *driver;
+
+		util_strlcpy(subsys, sysname, sizeof(subsys));
+		driver = strchr(subsys, ':');
+		if (driver != NULL) {
+			driver[0] = '\0';
+			driver = &driver[1];
+			util_strlcpy(path, "/subsystem/", sizeof(path_full) - sys_path_len);
+			util_strlcat(path, subsys, sizeof(path_full) - sys_path_len);
+			util_strlcat(path, "/drivers/", sizeof(path_full) - sys_path_len);
+			util_strlcat(path, driver, sizeof(path_full) - sys_path_len);
+			if (stat(path_full, &statbuf) == 0)
+				goto found;
+
+			util_strlcpy(path, "/bus/", sizeof(path_full) - sys_path_len);
+			util_strlcat(path, subsys, sizeof(path_full) - sys_path_len);
+			util_strlcat(path, "/drivers/", sizeof(path_full) - sys_path_len);
+			util_strlcat(path, driver, sizeof(path_full) - sys_path_len);
+			if (stat(path_full, &statbuf) == 0)
+				goto found;
+		}
+		goto out;
+	}
+
+	util_strlcpy(path, "/subsystem/", sizeof(path_full) - sys_path_len);
+	util_strlcat(path, subsystem, sizeof(path_full) - sys_path_len);
+	util_strlcat(path, "/devices/", sizeof(path_full) - sys_path_len);
+	util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
+	if (stat(path_full, &statbuf) == 0)
+		goto found;
+
+	util_strlcpy(path, "/bus/", sizeof(path_full) - sys_path_len);
+	util_strlcat(path, subsystem, sizeof(path_full) - sys_path_len);
+	util_strlcat(path, "/devices/", sizeof(path_full) - sys_path_len);
+	util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
+	if (stat(path_full, &statbuf) == 0)
+		goto found;
+
+	util_strlcpy(path, "/class/", sizeof(path_full) - sys_path_len);
+	util_strlcat(path, subsystem, sizeof(path_full) - sys_path_len);
+	util_strlcat(path, "/", sizeof(path_full) - sys_path_len);
+	util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
+	if (stat(path_full, &statbuf) == 0)
+		goto found;
+out:
+	return NULL;
+found:
+	return udev_device_new_from_syspath(udev, path_full);
+}
+
 static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
 {
 	struct udev_device *udev_device_parent = NULL;
diff --git a/udev/lib/libudev.h b/udev/lib/libudev.h
index fabe59d7d7..3f4cccf8c3 100644
--- a/udev/lib/libudev.h
+++ b/udev/lib/libudev.h
@@ -59,6 +59,7 @@ extern const char *udev_list_entry_get_value(struct udev_list_entry *list_entry)
 struct udev_device;
 extern struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath);
 extern struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum);
+extern struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname);
 extern struct udev_device *udev_device_get_parent(struct udev_device *udev_device);
 extern struct udev_device *udev_device_get_parent_with_subsystem(struct udev_device *udev_device, const char *subsystem);
 extern struct udev_device *udev_device_ref(struct udev_device *udev_device);
diff --git a/udev/lib/test-libudev.c b/udev/lib/test-libudev.c
index 854a0a9faa..65d84159ce 100644
--- a/udev/lib/test-libudev.c
+++ b/udev/lib/test-libudev.c
@@ -154,6 +154,40 @@ static int test_device_devnum(struct udev *udev)
 	return 0;
 }
 
+static int test_device_subsys_name(struct udev *udev)
+{
+	struct udev_device *device;
+
+	printf("looking up device: 'block':'sda'\n");
+	device = udev_device_new_from_subsystem_sysname(udev, "block", "sda");
+	if (device == NULL)
+		return -1;
+	print_device(device);
+	udev_device_unref(device);
+
+	printf("looking up device: 'subsystem':'pci'\n");
+	device = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
+	if (device == NULL)
+		return -1;
+	print_device(device);
+	udev_device_unref(device);
+
+	printf("looking up device: 'drivers':'scsi:sd'\n");
+	device = udev_device_new_from_subsystem_sysname(udev, "drivers", "scsi:sd");
+	if (device == NULL)
+		return -1;
+	print_device(device);
+	udev_device_unref(device);
+
+	printf("looking up device: 'module':'printk'\n");
+	device = udev_device_new_from_subsystem_sysname(udev, "module", "printk");
+	if (device == NULL)
+		return -1;
+	print_device(device);
+	udev_device_unref(device);
+	return 0;
+}
+
 static int test_enumerate_print_list(struct udev_enumerate *enumerate)
 {
 	struct udev_list_entry *list_entry;
@@ -269,7 +303,59 @@ static int test_queue(struct udev *udev)
 	return 0;
 }
 
-int main(int argc, char *argv[], char *envp[])
+static int test_enumerate(struct udev *udev, const char *subsystem)
+{
+	struct udev_enumerate *udev_enumerate;
+
+	printf("enumerate '%s'\n", subsystem == NULL ? "<all>" : subsystem);
+	udev_enumerate = udev_enumerate_new(udev);
+	if (udev_enumerate == NULL)
+		return -1;
+	udev_enumerate_add_match_subsystem(udev_enumerate, subsystem);
+	udev_enumerate_scan_devices(udev_enumerate);
+	test_enumerate_print_list(udev_enumerate);
+	udev_enumerate_unref(udev_enumerate);
+
+	printf("enumerate 'block'\n");
+	udev_enumerate = udev_enumerate_new(udev);
+	if (udev_enumerate == NULL)
+		return -1;
+	udev_enumerate_add_match_subsystem(udev_enumerate,"block");
+	udev_enumerate_scan_devices(udev_enumerate);
+	test_enumerate_print_list(udev_enumerate);
+	udev_enumerate_unref(udev_enumerate);
+
+	printf("enumerate 'not block'\n");
+	udev_enumerate = udev_enumerate_new(udev);
+	if (udev_enumerate == NULL)
+		return -1;
+	udev_enumerate_add_nomatch_subsystem(udev_enumerate, "block");
+	udev_enumerate_scan_devices(udev_enumerate);
+	test_enumerate_print_list(udev_enumerate);
+	udev_enumerate_unref(udev_enumerate);
+
+	printf("enumerate 'pci, mem, vc'\n");
+	udev_enumerate = udev_enumerate_new(udev);
+	if (udev_enumerate == NULL)
+		return -1;
+	udev_enumerate_add_match_subsystem(udev_enumerate, "pci");
+	udev_enumerate_add_match_subsystem(udev_enumerate, "mem");
+	udev_enumerate_add_match_subsystem(udev_enumerate, "vc");
+	udev_enumerate_scan_devices(udev_enumerate);
+	test_enumerate_print_list(udev_enumerate);
+	udev_enumerate_unref(udev_enumerate);
+
+	printf("enumerate 'subsystem'\n");
+	udev_enumerate = udev_enumerate_new(udev);
+	if (udev_enumerate == NULL)
+		return -1;
+	udev_enumerate_scan_subsystems(udev_enumerate);
+	test_enumerate_print_list(udev_enumerate);
+	udev_enumerate_unref(udev_enumerate);
+	return 0;
+}
+
+int main(int argc, char *argv[])
 {
 	struct udev *udev = NULL;
 	static const struct option options[] = {
@@ -281,7 +367,6 @@ int main(int argc, char *argv[], char *envp[])
 		{ "version", no_argument, NULL, 'V' },
 		{}
 	};
-	struct udev_enumerate *udev_enumerate;
 	const char *syspath = "/devices/virtual/mem/null";
 	const char *subsystem = NULL;
 	const char *socket = "@/org/kernel/udev/monitor";
@@ -342,53 +427,10 @@ int main(int argc, char *argv[], char *envp[])
 
 	test_device(udev, syspath);
 	test_device_devnum(udev);
+	test_device_subsys_name(udev);
 	test_device_parents(udev, syspath);
 
-	printf("enumerate '%s'\n", subsystem == NULL ? "<all>" : subsystem);
-	udev_enumerate = udev_enumerate_new(udev);
-	if (udev_enumerate == NULL)
-		return -1;
-	udev_enumerate_add_match_subsystem(udev_enumerate, subsystem);
-	udev_enumerate_scan_devices(udev_enumerate);
-	test_enumerate_print_list(udev_enumerate);
-	udev_enumerate_unref(udev_enumerate);
-
-	printf("enumerate 'block'\n");
-	udev_enumerate = udev_enumerate_new(udev);
-	if (udev_enumerate == NULL)
-		return -1;
-	udev_enumerate_add_match_subsystem(udev_enumerate,"block");
-	udev_enumerate_scan_devices(udev_enumerate);
-	test_enumerate_print_list(udev_enumerate);
-	udev_enumerate_unref(udev_enumerate);
-
-	printf("enumerate 'not block'\n");
-	udev_enumerate = udev_enumerate_new(udev);
-	if (udev_enumerate == NULL)
-		return -1;
-	udev_enumerate_add_nomatch_subsystem(udev_enumerate, "block");
-	udev_enumerate_scan_devices(udev_enumerate);
-	test_enumerate_print_list(udev_enumerate);
-	udev_enumerate_unref(udev_enumerate);
-
-	printf("enumerate 'pci, mem, vc'\n");
-	udev_enumerate = udev_enumerate_new(udev);
-	if (udev_enumerate == NULL)
-		return -1;
-	udev_enumerate_add_match_subsystem(udev_enumerate, "pci");
-	udev_enumerate_add_match_subsystem(udev_enumerate, "mem");
-	udev_enumerate_add_match_subsystem(udev_enumerate, "vc");
-	udev_enumerate_scan_devices(udev_enumerate);
-	test_enumerate_print_list(udev_enumerate);
-	udev_enumerate_unref(udev_enumerate);
-
-	printf("enumerate 'subsystem'\n");
-	udev_enumerate = udev_enumerate_new(udev);
-	if (udev_enumerate == NULL)
-		return -1;
-	udev_enumerate_scan_subsystems(udev_enumerate);
-	test_enumerate_print_list(udev_enumerate);
-	udev_enumerate_unref(udev_enumerate);
+	test_enumerate(udev, subsystem);
 
 	test_queue(udev);