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-rw-r--r--wait_for_sysfs.c334
1 files changed, 334 insertions, 0 deletions
diff --git a/wait_for_sysfs.c b/wait_for_sysfs.c
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index 0000000000..b9efcddf87
--- /dev/null
+++ b/wait_for_sysfs.c
@@ -0,0 +1,334 @@
+/*
+ * wait_for_sysfs.c - small program to delay the execution
+ * of /etc/hotplug.d/ programs, until sysfs
+ * is populated by the kernel. Depending on
+ * the type of device, we wait for all expected
+ * directories and then just exit.
+ *
+ * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ *
+ * 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 "libsysfs/sysfs/libsysfs.h"
+
+#ifdef LOG
+unsigned char logname[LOGNAME_SIZE];
+void log_message(int level, const char *format, ...)
+{
+ va_list args;
+
+ va_start(args, format);
+ vsyslog(level, format, args);
+ va_end(args);
+}
+#endif
+
+#define WAIT_MAX_SECONDS 5
+#define WAIT_LOOP_PER_SECOND 20
+
+static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev)
+{
+ static struct class_file {
+ char *subsystem;
+ char *file;
+ } class_files[] = {
+ { .subsystem = "net", .file = "ifindex" },
+ { .subsystem = "usb_host", .file = NULL },
+ { .subsystem = "pcmcia_socket", .file = NULL },
+ { NULL, NULL }
+ };
+ struct class_file *classfile;
+ const char *file = "dev";
+ int loop;
+
+ /* look if we want to look for another file instead of "dev" */
+ for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
+ if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
+ if (classfile->file == NULL) {
+ dbg("class '%s' has no file to wait for", class_dev->classname);
+ return 0;
+ }
+ file = classfile->file;
+ break;
+ }
+ }
+ dbg("looking at class '%s' for specific file '%s'", class_dev->classname, file);
+
+ loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+ while (--loop) {
+ if (sysfs_get_classdev_attr(class_dev, file) != NULL) {
+ dbg("class '%s' specific file '%s' found", class_dev->classname, file);
+ return 0;
+ }
+ }
+
+ dbg("error: getting bus '%s' specific file '%s'", class_dev->classname, file);
+ return -1;
+}
+
+static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
+{
+ char **device;
+
+ static char *devices_without_link[] = {
+ "nb",
+ "ram",
+ "loop",
+ "fd",
+ "md",
+ "dos_cd",
+ "double",
+ "flash",
+ "msd",
+ "rflash",
+ "rom",
+ "rrom",
+ "sbpcd",
+ "pcd",
+ "pf",
+ "scd",
+ "sit",
+ "lp",
+ "ubd",
+ "vcs",
+ "vcsa",
+ "console",
+ "tty",
+ "ttyS",
+ NULL
+ };
+
+ for (device = devices_without_link; *device != NULL; device++) {
+ int len = strlen(*device);
+
+ /* look if name matches */
+ if (strncmp(class_dev->name, *device, len) != 0)
+ continue;
+
+ /* exact match */
+ if (strlen(class_dev->name) == len)
+ return 1;
+
+ /* instance numbers are matching too */
+ if (isdigit(class_dev->name[len]))
+ return 1;
+ }
+
+ return 0;
+}
+
+static int wait_for_bus_device(struct sysfs_device *device_dev)
+{
+ static struct bus_file {
+ char *bus;
+ char *file;
+ } bus_files[] = {
+ { .bus = "scsi", .file = "vendor" },
+ { .bus = "usb", .file = "idVendor" },
+ { .bus = "usb", .file = "iInterface" },
+ { .bus = "usb-serial", .file = "detach_state" },
+ { .bus = "ide", .file = "detach_state" },
+ { .bus = "pci", .file = "vendor" },
+ { NULL }
+ };
+ struct bus_file *busfile;
+ int loop;
+
+ /* wait for the /bus-device link to the /device-device */
+ loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+ while (--loop) {
+ if (sysfs_get_device_bus(device_dev) == 0)
+ break;
+
+ usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+ }
+ if (loop == 0) {
+ dbg("error: getting /bus-device link");
+ return -1;
+ }
+ dbg("/bus-device link found for bus '%s'", device_dev->bus);
+
+ /* wait for a bus specific file to show up */
+ loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+ while (--loop) {
+ for (busfile = bus_files; busfile->bus != NULL; busfile++) {
+ if (strcmp(device_dev->bus, busfile->bus) == 0) {
+ dbg("looking at bus '%s' for specific file '%s'", device_dev->bus, busfile->file);
+ if (sysfs_get_device_attr(device_dev, busfile->file) != NULL) {
+ dbg("bus '%s' specific file '%s' found", device_dev->bus, busfile->file);
+ return 0;
+ }
+ if (busfile->bus == NULL) {
+ info("error: unknown bus, update the build-in list '%s'", device_dev->bus);
+ return -1;
+ }
+ }
+ }
+ }
+
+ dbg("error: getting bus '%s' specific file '%s'", device_dev->bus, busfile->file);
+ return -1;
+}
+
+int main(int argc, char *argv[], char *envp[])
+{
+ const char *devpath = "";
+ const char *action;
+ const char *subsystem;
+ char sysfs_path[SYSFS_PATH_MAX];
+ char filename[SYSFS_PATH_MAX];
+ struct sysfs_class_device *class_dev;
+ struct sysfs_class_device *class_dev_parent;
+ struct sysfs_device *device_dev = NULL;
+ int loop;
+ int rc = 0;
+
+ if (argc != 2) {
+ dbg("error: subsystem");
+ return 1;
+ }
+ subsystem = argv[1];
+
+ devpath = getenv ("DEVPATH");
+ if (!devpath) {
+ dbg("error: no DEVPATH");
+ return 1;
+ }
+
+ action = getenv ("ACTION");
+ if (!action) {
+ dbg("error: no ACTION");
+ return 1;
+ }
+
+ if (strcmp(action, "add") != 0)
+ return 0;
+
+ if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
+ dbg("error: no sysfs path");
+ return 2;
+ }
+
+ if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
+ /* open the class device we are called for */
+ snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
+ filename[SYSFS_PATH_MAX-1] = '\0';
+
+ loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+ while (--loop) {
+ class_dev = sysfs_open_class_device_path(filename);
+ if (class_dev)
+ break;
+ }
+ if (class_dev == NULL) {
+ dbg("error: getting class_device");
+ rc = 4;
+ goto exit;
+ }
+ dbg("class_device opened '%s'", filename);
+
+ wait_for_class_device_attributes(class_dev);
+
+ if (class_device_expect_no_device_link(class_dev)) {
+ dbg("no device symlink expected");
+ sysfs_close_class_device(class_dev);
+ goto exit;
+ }
+
+ /* 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 /device-device */
+ dbg("waiting for symlink to /device-device");
+ loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+ while (--loop) {
+ if (class_dev_parent)
+ device_dev = sysfs_get_classdev_device(class_dev_parent);
+ else
+ device_dev = sysfs_get_classdev_device(class_dev);
+
+ if (device_dev)
+ break;
+
+ usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+ }
+ if (device_dev == NULL) {
+ dbg("error: getting /device-device");
+ sysfs_close_class_device(class_dev);
+ rc = 5;
+ goto exit;
+ }
+ dbg("device symlink found pointing to '%s'", device_dev->path);
+
+ /* wait for the bus value */
+ if (wait_for_bus_device(device_dev) != 0)
+ rc = 6;
+ sysfs_close_class_device(class_dev);
+
+ /* finished */
+ goto exit;
+
+ } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
+ /* open the path we are called for */
+ snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
+ filename[SYSFS_PATH_MAX-1] = '\0';
+
+ loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+ while (--loop) {
+ device_dev = sysfs_open_device_path(filename);
+ if (device_dev)
+ break;
+ }
+ if (device_dev == NULL) {
+ dbg("error: getting /device-device");
+ rc = 4;
+ goto exit;
+ }
+ dbg("device_device opened '%s'", filename);
+
+ /* wait for the bus value */
+ if (wait_for_bus_device(device_dev) != 0)
+ rc = 9;
+
+ sysfs_close_device(device_dev);
+
+ /* finished */
+ goto exit;
+
+ } else {
+ dbg("unhandled sysfs path, no need to wait");
+ }
+
+exit:
+ if (rc == 0)
+ info("result: waiting for sysfs successful '%s'", devpath);
+ else
+ info("result: waiting for sysfs failed '%s'", devpath);
+
+ return rc;
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-08-13 23:44:08 +0000