[PATCH] expose sysfs functions for sharing it

This patch exposes the wait_for_sysfs functions to all possible users,
so we need to maintain only one list of exceptions. The last list is
hereby removed from udev.c.

1 files changed, 387 insertions, 0 deletions

diff --git a/udev_sysfs.c b/udev_sysfs.c
new file mode 100644
index 00000000..624f5358
--- /dev/null
+++ b/udev_sysfs.c
@@ -0,0 +1,387 @@
+/*
+ * udev_sysfs.c  - sysfs linux kernel specific knowledge
+ *
+ * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License as published by the
+ *	Free Software Foundation version 2 of the License.
+ * 
+ *	This program is distributed in the hope that it will be useful, but
+ *	WITHOUT ANY WARRANTY; without even the implied warranty of
+ *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *	General Public License for more details.
+ * 
+ *	You should have received a copy of the GNU General Public License along
+ *	with this program; if not, write to the Free Software Foundation, Inc.,
+ *	675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#include "logging.h"
+#include "udev_version.h"
+#include "udev_sysfs.h"
+#include "libsysfs/sysfs/libsysfs.h"
+
+/* list of subsystem specific files
+ * NULL if there is no file to wait for
+ */
+static struct subsystem_file {
+	char *subsystem;
+	char *file;
+} subsystem_files[] = {
+	{ .subsystem = "net",		.file = "ifindex" },
+	{ .subsystem = "scsi_host",	.file = "unique_id" },
+	{ .subsystem = "scsi_device",	.file = NULL },
+	{ .subsystem = "pcmcia_socket",	.file = "card_type" },
+	{ .subsystem = "usb_host",	.file = NULL },
+	{ .subsystem = "bluetooth",	.file = "address" },
+	{ .subsystem = "firmware",	.file = "data" },
+	{ .subsystem = "i2c-adapter",	.file = NULL },
+	{ .subsystem = "pci_bus",	.file = NULL },
+	{ .subsystem = "ieee1394",	.file = NULL },
+	{ .subsystem = "ieee1394_host",	.file = NULL },
+	{ .subsystem = "ieee1394_node",	.file = NULL },
+	{ NULL, NULL }
+};
+
+int subsystem_expect_no_dev(const char *subsystem)
+{
+	struct subsystem_file *file;
+
+	for (file = subsystem_files; file->subsystem != NULL; file++)
+		if (strcmp(subsystem, file->subsystem) == 0)
+			return 1;
+
+	return 0;
+}
+
+/* get subsystem specific files, returns "dev" if no other found */
+static char *get_subsystem_specific_file(const char *subsystem)
+{
+	struct subsystem_file *file;
+
+	/* look if we want to look for another file instead of "dev" */
+	for (file = subsystem_files; file->subsystem != NULL; file++)
+		if (strcmp(subsystem, file->subsystem) == 0)
+			return file->file;
+
+	return "dev";
+}
+
+/* wait for class pecific file to show up */
+static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev,
+					    const char **error)
+{
+	const char *file;
+	char filename[SYSFS_PATH_MAX];
+	int loop;
+
+	file = get_subsystem_specific_file(class_dev->classname);
+	if (file == NULL) {
+		dbg("class '%s' has no file to wait for", class_dev->classname);
+		return 0;
+	}
+
+	strcpy(filename, class_dev->path);
+	strcat(filename, "/");
+	strcat(filename, file);
+	dbg("looking at class '%s' for specific file '%s' with full name %s", class_dev->classname, file, filename);
+
+	loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+	while (--loop) {
+		struct stat stats;
+
+		if (stat(class_dev->path, &stats) == -1) {
+			dbg("'%s' now disappeared (probably remove has beaten us)", class_dev->path);
+			return -ENODEV;
+		}
+
+		if (stat(filename, &stats) == 0) {
+			dbg("class '%s' specific file '%s' found", class_dev->classname, file);
+			return 0;
+		}
+
+		usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+	}
+
+	dbg("error: getting class '%s' specific file '%s'", class_dev->classname, file);
+	if (error)
+		*error = "class specific file unavailable";
+	return -ENOENT;
+}
+
+/* check if we need to wait for a physical device */
+static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
+{
+	/* list of devices without a "device" symlink to the physical device
+	 * if device is set to NULL, no devices in that subsystem has a link */
+	static struct class_device {
+		char *subsystem;
+		char *device;
+	} class_device[] = {
+		{ .subsystem = "block",		.device = "double" },
+		{ .subsystem = "block",		.device = "nb" },
+		{ .subsystem = "block",		.device = "ram" },
+		{ .subsystem = "block",		.device = "loop" },
+		{ .subsystem = "block",		.device = "fd" },
+		{ .subsystem = "block",		.device = "md" },
+		{ .subsystem = "block",		.device = "dos_cd" },
+		{ .subsystem = "block",		.device = "rflash" },
+		{ .subsystem = "block",		.device = "rom" },
+		{ .subsystem = "block",		.device = "rrom" },
+		{ .subsystem = "block",		.device = "flash" },
+		{ .subsystem = "block",		.device = "msd" },
+		{ .subsystem = "block",		.device = "sbpcd" },
+		{ .subsystem = "block",		.device = "pcd" },
+		{ .subsystem = "block",		.device = "pf" },
+		{ .subsystem = "block",		.device = "scd" },
+		{ .subsystem = "block",		.device = "ubd" },
+		{ .subsystem = "block",		.device = "dm-" },
+		{ .subsystem = "input",		.device = "event" },
+		{ .subsystem = "input",		.device = "mice" },
+		{ .subsystem = "input",		.device = "mouse" },
+		{ .subsystem = "input",		.device = "ts" },
+		{ .subsystem = "vc",		.device = NULL },
+		{ .subsystem = "tty",		.device = NULL },
+		{ .subsystem = "cpuid",		.device = "cpu" },
+		{ .subsystem = "graphics",	.device = "fb" },
+		{ .subsystem = "mem",		.device = NULL },
+		{ .subsystem = "misc",		.device = NULL },
+		{ .subsystem = "msr",		.device = NULL },
+		{ .subsystem = "netlink",	.device = NULL },
+		{ .subsystem = "net",		.device = "sit" },
+		{ .subsystem = "net",		.device = "lo" },
+		{ .subsystem = "net",		.device = "tap" },
+		{ .subsystem = "net",		.device = "ipsec" },
+		{ .subsystem = "net",		.device = "dummy" },
+		{ .subsystem = "net",		.device = "irda" },
+		{ .subsystem = "net",		.device = "ppp" },
+		{ .subsystem = "ppp",		.device = NULL },
+		{ .subsystem = "sound",		.device = NULL },
+		{ .subsystem = "printer",	.device = "lp" },
+		{ .subsystem = "nvidia",	.device = NULL },
+		{ .subsystem = "video4linux",	.device = "vbi" },
+		{ .subsystem = "lirc",		.device = NULL },
+		{ .subsystem = "firmware",	.device = NULL },
+		{ .subsystem = "drm",		.device = NULL },
+		{ .subsystem = "pci_bus",	.device = NULL },
+		{ .subsystem = "ieee1394",	.device = NULL },
+		{ .subsystem = "ieee1394_host",	.device = NULL },
+		{ .subsystem = "ieee1394_node",	.device = NULL },
+		{ .subsystem = "raw",		.device = NULL },
+		{ NULL, NULL }
+	};
+	struct class_device *classdevice;
+	int len;
+
+	for (classdevice = class_device; classdevice->subsystem != NULL; classdevice++) {
+		if (strcmp(class_dev->classname, classdevice->subsystem) == 0) {
+			/* see if no device in this class is expected to have a device-link */
+			if (classdevice->device == NULL)
+				return 1;
+
+			len = strlen(classdevice->device);
+
+			/* see if device name matches */
+			if (strncmp(class_dev->name, classdevice->device, len) != 0)
+				continue;
+
+			/* exact name match */
+			if (strlen(class_dev->name) == len)
+				return 1;
+
+			/* name match with instance number */
+			if (isdigit(class_dev->name[len]))
+				return 1;
+		}
+	}
+
+	return 0;
+}
+
+/* skip waiting for the bus */
+static int class_device_expect_no_bus(struct sysfs_class_device *class_dev)
+{
+	static char *devices_without_bus[] = {
+		"scsi_host",
+		"i2c-adapter",
+		NULL
+	};
+	char **device;
+
+	for (device = devices_without_bus; *device != NULL; device++) {
+		int len = strlen(*device);
+
+		if (strncmp(class_dev->classname, *device, len) == 0)
+			return 1;
+	}
+
+	return 0;
+}
+
+/* wait for the bus and for a bus specific file to show up */
+int wait_for_bus_device(struct sysfs_device *devices_dev,
+			const char **error)
+{
+	static struct bus_file {
+		char *bus;
+		char *file;
+	} bus_files[] = {
+		{ .bus = "scsi",	.file = "vendor" },
+		{ .bus = "usb",		.file = "idVendor" },
+		{ .bus = "usb",		.file = "iInterface" },
+		{ .bus = "usb",		.file = "bNumEndpoints" },
+		{ .bus = "usb-serial",	.file = "detach_state" },
+		{ .bus = "ide",		.file = "detach_state" },
+		{ .bus = "pci",		.file = "vendor" },
+		{ .bus = "platform",	.file = "detach_state" },
+		{ .bus = "i2c",		.file = "detach_state" },
+		{ NULL }
+	};
+	struct bus_file *busfile;
+	int loop;
+
+	/* wait for the bus device link to the devices device */
+	loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+	while (--loop) {
+		if (sysfs_get_device_bus(devices_dev) == 0)
+			break;
+
+		usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+	}
+	if (loop == 0) {
+		dbg("error: getting bus device link");
+		if (error)
+			*error = "no bus device link";
+		return -1;
+	}
+	dbg("bus device link found for bus '%s'", devices_dev->bus);
+
+	/* wait for a bus specific file to show up */
+	loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+	while (--loop) {
+		int found = 0;
+
+		for (busfile = bus_files; busfile->bus != NULL; busfile++) {
+			if (strcmp(devices_dev->bus, busfile->bus) == 0) {
+				found = 1;
+				dbg("looking at bus '%s' for specific file '%s'", devices_dev->bus, busfile->file);
+				if (sysfs_get_device_attr(devices_dev, busfile->file) != NULL) {
+					dbg("bus '%s' specific file '%s' found", devices_dev->bus, busfile->file);
+					return 0;
+				}
+			}
+		}
+		if (found == 0) {
+			if (error)
+				*error = "unknown bus";
+			info("error: unknown bus, please report to "
+			     "<linux-hotplug-devel@lists.sourceforge.net> '%s'", devices_dev->bus);
+			return -1;
+		}
+		usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+	}
+
+	dbg("error: getting bus '%s' specific file '%s'", devices_dev->bus, busfile->file);
+	if (error)
+		*error = "bus specific file unavailable";
+	return -1;
+}
+
+
+struct sysfs_class_device *open_class_device_wait(const char *path)
+{
+	struct sysfs_class_device *class_dev;
+	int loop;
+
+	loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+	while (--loop) {
+		class_dev = sysfs_open_class_device_path(path);
+		if (class_dev)
+			break;
+
+		usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+	}
+
+	return (class_dev);
+}
+
+int wait_for_class_device(struct sysfs_class_device *class_dev,
+			  const char **error)
+{
+	struct sysfs_class_device *class_dev_parent;
+	struct sysfs_device *devices_dev = NULL;
+	int loop;
+
+	if (wait_for_class_device_attributes(class_dev, error) != 0)
+		return -ENOENT;
+
+	/* skip devices without devices-link */
+	if (class_device_expect_no_device_link(class_dev)) {
+		dbg("no device symlink expected for '%s', ", class_dev->name);
+		return -ENODEV;
+	}
+
+	/* the symlink may be on the parent device */
+	class_dev_parent = sysfs_get_classdev_parent(class_dev);
+	if (class_dev_parent)
+		dbg("looking at parent device for device link '%s'", class_dev_parent->path);
+
+	/* wait for the symlink to the devices device */
+	dbg("waiting for symlink to devices device");
+	loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+	while (--loop) {
+		if (class_dev_parent)
+			devices_dev = sysfs_get_classdev_device(class_dev_parent);
+		else
+			devices_dev = sysfs_get_classdev_device(class_dev);
+
+		if (devices_dev)
+			break;
+
+		usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+	}
+	if (!devices_dev) {
+		dbg(" error: no devices device symlink found");
+		if (error)
+			*error = "no device symlink";
+		return -ENODEV;
+	}
+	dbg("device symlink found pointing to '%s'", devices_dev->path);
+
+	/* wait for the bus value */
+	if (class_device_expect_no_bus(class_dev)) {
+		dbg("no bus device expected for '%s', ", class_dev->classname);
+		return 0;
+	} else {
+		return wait_for_bus_device(devices_dev, error);
+	}
+}
+
+struct sysfs_device *open_devices_device_wait(const char *path)
+{
+	struct sysfs_device *devices_dev;
+	int loop;
+
+	loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+	while (--loop) {
+		devices_dev = sysfs_open_device_path(path);
+		if (devices_dev)
+			break;
+
+		usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+	}
+
+	return(devices_dev);
+}