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libudev: add udev event monitor API

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This commit is contained in:
Kay Sievers 2008-08-28 23:05:01 +02:00
parent 530fc1f526
commit ba6929f669
9 changed files with 441 additions and 63 deletions
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7
NEWS
View file

@ -2,6 +2,13 @@ udev 127
========
Bugfixes.
A shared library "libudev" will be installed now, to access udev
device information. DeviceKit, the successor of HAL, will need this
library to access the udev database and search sysfs for devices.
The library is currently in an experimental state, also the API is
expected to change, as long as the DeviceKit integration isn't
finished.
udev 126
========
We use ./configure now. See INSTALL for details. Current

1
udev/lib/Makefile.am
View file

@ -24,6 +24,7 @@ libudev_la_SOURCES =\
libudev-utils.c \
libudev-device.c \
libudev-enumerate.c \
libudev-monitor.c \
../list.h \
../udev.h \
../udev_utils.c \

6
udev/lib/exported_symbols
View file

@ -15,3 +15,9 @@ udev_device_get_subsystem
udev_device_get_devlinks
udev_device_get_properties
udev_devices_enumerate
udev_monitor_new_from_socket
udev_monitor_ref
udev_monitor_unref
udev_monitor_get_udev
udev_monitor_get_fd
udev_monitor_get_device

98
udev/lib/libudev-device.c
View file

@ -32,16 +32,22 @@
#include "libudev-private.h"
#include "../udev.h"
static struct udev_device *device_init(struct udev *udev)
struct udev_device *device_init(struct udev *udev)
{
struct udev_device *udev_device;
if (udev == NULL)
return NULL;
udev_device = malloc(sizeof(struct udev_device));
if (udev_device == NULL)
return NULL;
memset(udev_device, 0x00, sizeof(struct udev_device));
udev_device->refcount = 1;
udev_device->udev = udev;
INIT_LIST_HEAD(&udev_device->link_list);
INIT_LIST_HEAD(&udev_device->env_list);
log_info(udev_device->udev, "udev_device: %p created\n", udev_device);
return udev_device;
}
@ -64,8 +70,15 @@ struct udev_device *udev_device_new_from_devpath(struct udev *udev, const char *
char path[PATH_SIZE];
struct stat statbuf;
struct udev_device *udev_device;
struct udevice *udevice;
struct name_entry *name_loop;
int err;
if (udev == NULL)
return NULL;
if (devpath == NULL)
return NULL;
strlcpy(path, udev_get_sys_path(udev), sizeof(path));
strlcat(path, devpath, sizeof(path));
if (stat(path, &statbuf) != 0)
@ -77,20 +90,38 @@ struct udev_device *udev_device_new_from_devpath(struct udev *udev, const char *
if (udev_device == NULL)
return NULL;
udev_device->udevice = udev_device_init(NULL);
if (udev_device->udevice == NULL) {
udevice = udev_device_init(NULL);
if (udevice == NULL) {
free(udev_device);
return NULL;
}
log_info(udev, "device %p created\n", udev_device);
/* resolve possible symlink to real path */
strlcpy(path, devpath, sizeof(path));
sysfs_resolve_link(path, sizeof(path));
udev_device->devpath = strdup(path);
log_info(udev, "device %p has devpath '%s'\n", udev_device, udev_device_get_devpath(udev_device));
err = udev_db_get_device(udev_device->udevice, path);
err = udev_db_get_device(udevice, path);
if (err >= 0)
log_info(udev, "device %p filled with udev database data\n", udev_device);
log_info(udev, "device %p filled with %s data\n", udev_device, udev_device_get_devpath(udev_device));
if (udevice->name[0] != '\0')
asprintf(&udev_device->devname, "%s/%s", udev_get_dev_path(udev), udevice->name);
list_for_each_entry(name_loop, &udevice->symlink_list, node) {
char name[PATH_SIZE];
strlcpy(name, udev_get_dev_path(udev), sizeof(name));
strlcat(name, "/", sizeof(name));
strlcat(name, name_loop->name, sizeof(name));
name_list_add(&udev_device->link_list, name, 0);
}
list_for_each_entry(name_loop, &udevice->env_list, node)
name_list_add(&udev_device->env_list, name_loop->name, 0);
udev_device_cleanup(udevice);
return udev_device;
}
@ -103,6 +134,8 @@ struct udev_device *udev_device_new_from_devpath(struct udev *udev, const char *
**/
struct udev *udev_device_get_udev(struct udev_device *udev_device)
{
if (udev_device == NULL)
return NULL;
return udev_device->udev;
}
@ -116,6 +149,8 @@ struct udev *udev_device_get_udev(struct udev_device *udev_device)
**/
struct udev_device *udev_device_ref(struct udev_device *udev_device)
{
if (udev_device == NULL)
return NULL;
udev_device->refcount++;
return udev_device;
}
@ -130,10 +165,17 @@ struct udev_device *udev_device_ref(struct udev_device *udev_device)
**/
void udev_device_unref(struct udev_device *udev_device)
{
if (udev_device == NULL)
return;
udev_device->refcount--;
if (udev_device->refcount > 0)
return;
udev_device_cleanup(udev_device->udevice);
free(udev_device->devpath);
free(udev_device->devname);
free(udev_device->subsystem);
name_list_cleanup(&udev_device->link_list);
name_list_cleanup(&udev_device->env_list);
log_info(udev_device->udev, "udev_device: %p released\n", udev_device);
free(udev_device);
}
@ -148,7 +190,9 @@ void udev_device_unref(struct udev_device *udev_device)
**/
const char *udev_device_get_devpath(struct udev_device *udev_device)
{
return udev_device->udevice->dev->devpath;
if (udev_device == NULL)
return NULL;
return udev_device->devpath;
}
/**
@ -156,16 +200,15 @@ const char *udev_device_get_devpath(struct udev_device *udev_device)
* @udev_device: udev device
*
* Retrieve the device node file name belonging to the udev device.
* The path does not contain the device directory, and does not contain
* a leading '/'.
* The path is an absolute path, and starts with the device directory.
*
* Returns: the device node file name of the udev device, or #NULL if no device node exists
**/
const char *udev_device_get_devname(struct udev_device *udev_device)
{
if (udev_device->udevice->name[0] == '\0')
if (udev_device == NULL)
return NULL;
return udev_device->udevice->name;
return udev_device->devname;
}
/**
@ -179,13 +222,16 @@ const char *udev_device_get_devname(struct udev_device *udev_device)
**/
const char *udev_device_get_subsystem(struct udev_device *udev_device)
{
struct sysfs_device *dev = udev_device->udevice->dev;
if (dev->subsystem[0] != '\0')
return dev->subsystem;
if (util_get_sys_subsystem(udev_device->udev, dev->devpath,
dev->subsystem, sizeof(dev->subsystem)) < 2)
char subsystem[NAME_SIZE];
if (udev_device == NULL)
return NULL;
return dev->subsystem;
if (udev_device->subsystem != NULL)
return udev_device->subsystem;
if (util_get_sys_subsystem(udev_device->udev, udev_device->devpath, subsystem, sizeof(subsystem)) < 2)
return NULL;
udev_device->subsystem = strdup(subsystem);
return udev_device->subsystem;
}
/**
@ -196,10 +242,9 @@ const char *udev_device_get_subsystem(struct udev_device *udev_device)
*
* Retrieve the device links pointing to the device file of the
* udev device. For every device link, the passed function will be
* called with the device link string. If the function returns 1,
* remaning device links will be ignored. The device link path
* does not contain the device directory, and does not contain
* a leading '/'.
* called with the device link string.
* The path is an absolute path, and starts with the device directory.
* If the function returns 1, remaning device links will be ignored.
*
* Returns: the number of device links passed to the caller, or a negative value on error
**/
@ -210,7 +255,9 @@ int udev_device_get_devlinks(struct udev_device *udev_device,
struct name_entry *name_loop;
int count = 0;
list_for_each_entry(name_loop, &udev_device->udevice->symlink_list, node) {
if (udev_device == NULL)
return -1;
list_for_each_entry(name_loop, &udev_device->link_list, node) {
count++;
if (cb(udev_device, name_loop->name, data) != 0)
break;
@ -238,7 +285,9 @@ int udev_device_get_properties(struct udev_device *udev_device,
struct name_entry *name_loop;
int count = 0;
list_for_each_entry(name_loop, &udev_device->udevice->env_list, node) {
if (udev_device == NULL)
return -1;
list_for_each_entry(name_loop, &udev_device->env_list, node) {
char name[PATH_SIZE];
char *val;
@ -249,6 +298,7 @@ int udev_device_get_properties(struct udev_device *udev_device,
continue;
val[0] = '\0';
val = &val[1];
count++;
if (cb(udev_device, name, val, data) != 0)
break;
}

216
udev/lib/libudev-monitor.c Normal file
View file

@ -0,0 +1,216 @@
/*
* libudev - interface to udev device information
*
* Copyright (C) 2008 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, either version 2 of the License, or
* (at your option) any later version.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include "libudev.h"
#include "libudev-private.h"
#include "../udev.h"
struct udev_monitor {
struct udev *udev;
int refcount;
int socket;
};
struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path)
{
struct udev_monitor *udev_monitor;
struct sockaddr_un saddr;
socklen_t addrlen;
const int on = 1;
if (udev == NULL)
return NULL;
if (socket_path == NULL)
return NULL;
udev_monitor = malloc(sizeof(struct udev_monitor));
if (udev_monitor == NULL)
return NULL;
memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
udev_monitor->refcount = 1;
udev_monitor->udev = udev;
memset(&saddr, 0x00, sizeof(saddr));
saddr.sun_family = AF_LOCAL;
strcpy(saddr.sun_path, socket_path);
addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path);
/* translate leading '@' to abstract namespace */
if (saddr.sun_path[0] == '@')
saddr.sun_path[0] = '\0';
udev_monitor->socket = socket(AF_LOCAL, SOCK_DGRAM, 0);
if (udev_monitor->socket == -1) {
log_err(udev, "error getting socket: %s\n", strerror(errno));
free(udev_monitor);
return NULL;
}
if (bind(udev_monitor->socket, (struct sockaddr *) &saddr, addrlen) < 0) {
log_err(udev, "bind failed: %s\n", strerror(errno));
close(udev_monitor->socket);
free(udev_monitor);
return NULL;
}
/* enable receiving of the sender credentials */
setsockopt(udev_monitor->socket, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
log_info(udev_monitor->udev, "udev_monitor: %p created\n", udev_monitor);
return udev_monitor;
}
struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return NULL;
udev_monitor->refcount++;
return udev_monitor;
}
void udev_monitor_unref(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return;
udev_monitor->refcount--;
if (udev_monitor->refcount > 0)
return;
close(udev_monitor->socket);
log_info(udev_monitor->udev, "udev_monitor: %p released\n", udev_monitor);
free(udev_monitor);
}
struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return NULL;
return udev_monitor->udev;
}
int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
{
if (udev_monitor == NULL)
return -1;
return udev_monitor->socket;
}
struct udev_device *udev_monitor_get_device(struct udev_monitor *udev_monitor)
{
struct udev_device *udev_device;
struct msghdr smsg;
struct cmsghdr *cmsg;
struct iovec iov;
struct ucred *cred;
char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
char buf[4096];
size_t bufpos;
if (udev_monitor == NULL)
return NULL;
memset(buf, 0x00, sizeof(buf));
iov.iov_base = &buf;
iov.iov_len = sizeof(buf);
memset (&smsg, 0x00, sizeof(struct msghdr));
smsg.msg_iov = &iov;
smsg.msg_iovlen = 1;
smsg.msg_control = cred_msg;
smsg.msg_controllen = sizeof(cred_msg);
if (recvmsg(udev_monitor->socket, &smsg, 0) < 0) {
if (errno != EINTR)
log_info(udev_monitor->udev, "unable to receive message");
return NULL;
}
cmsg = CMSG_FIRSTHDR(&smsg);
cred = (struct ucred *)CMSG_DATA (cmsg);
if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
log_info(udev_monitor->udev, "no sender credentials received, message ignored");
return NULL;
}
if (cred->uid != 0) {
log_info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
return NULL;
}
/* skip header */
bufpos = strlen(buf) + 1;
if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
log_info(udev_monitor->udev, "invalid message length");
return NULL;
}
/* check message header */
if (strstr(buf, "@/") == NULL) {
log_info(udev_monitor->udev, "unrecognized message header");
return NULL;
}
udev_device = device_init(udev_monitor->udev);
if (udev_device == NULL) {
return NULL;
}
while (bufpos < sizeof(buf)) {
char *key;
size_t keylen;
key = &buf[bufpos];
keylen = strlen(key);
if (keylen == 0)
break;
bufpos += keylen + 1;
if (strncmp(key, "DEVPATH=", 8) == 0) {
udev_device->devpath = strdup(&key[8]);
} else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
udev_device->subsystem = strdup(&key[10]);
} else if (strncmp(key, "DEVNAME=", 8) == 0) {
udev_device->devname = strdup(&key[8]);
} else if (strncmp(key, "DEVLINKS=", 9) == 0) {
char *slink = &key[9];
char *next = strchr(slink, ' ');
while (next != NULL) {
next[0] = '\0';
name_list_add(&udev_device->link_list, slink, 0);
slink = &next[1];
next = strchr(slink, ' ');
}
if (slink[0] != '\0')
name_list_add(&udev_device->link_list, slink, 0);
}
name_list_add(&udev_device->env_list, key, 0);
}
return udev_device;
}

14
udev/lib/libudev-private.h
View file

@ -23,17 +23,14 @@
#include "libudev.h"
#include "../udev.h"
struct udev {
int refcount;
void (*log_fn)(struct udev *udev,
int priority, const char *file, int line, const char *fn,
const char *format, va_list args);
};
struct udev_device {
int refcount;
struct udev *udev;
struct udevice *udevice;
char *devpath;
char *devname;
char *subsystem;
struct list_head link_list;
struct list_head env_list;
};
#ifdef USE_LOG
@ -57,6 +54,7 @@ static inline void udev_log(struct udev *udev,
__attribute__ ((format(printf, 6, 7))) {}
#endif
extern struct udev_device *device_init(struct udev *udev);
extern ssize_t util_get_sys_subsystem(struct udev *udev, const char *devpath, char *subsystem, size_t size);
#endif

15
udev/lib/libudev.c
View file

@ -32,6 +32,13 @@
#include "libudev-private.h"
#include "../udev.h"
struct udev {
int refcount;
void (*log_fn)(struct udev *udev,
int priority, const char *file, int line, const char *fn,
const char *format, va_list args);
};
void udev_log(struct udev *udev,
int priority, const char *file, int line, const char *fn,
const char *format, ...)
@ -110,6 +117,8 @@ struct udev *udev_new(void)
**/
struct udev *udev_ref(struct udev *udev)
{
if (udev == NULL)
return NULL;
udev->refcount++;
return udev;
}
@ -124,6 +133,8 @@ struct udev *udev_ref(struct udev *udev)
**/
void udev_unref(struct udev *udev)
{
if (udev == NULL)
return;
udev->refcount--;
if (udev->refcount > 0)
return;
@ -164,6 +175,8 @@ void udev_set_log_fn(struct udev *udev,
**/
const char *udev_get_sys_path(struct udev *udev)
{
if (udev == NULL)
return NULL;
return sysfs_path;
}
@ -179,5 +192,7 @@ const char *udev_get_sys_path(struct udev *udev)
**/
const char *udev_get_dev_path(struct udev *udev)
{
if (udev == NULL)
return NULL;
return udev_root;
}

8
udev/lib/libudev.h
View file

@ -22,6 +22,7 @@
struct udev;
struct udev_device;
struct udev_monitor;
extern struct udev *udev_new(void);
extern struct udev *udev_ref(struct udev *udev);
@ -54,4 +55,11 @@ extern int udev_devices_enumerate(struct udev *udev, const char *subsystem,
const char *devpath, const char *subsystem, const char *name, void *data),
void *data);
extern struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path);
extern struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor);
extern void udev_monitor_unref(struct udev_monitor *udev_monitor);
extern struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor);
extern int udev_monitor_get_fd(struct udev_monitor *udev_monitor);
extern struct udev_device *udev_monitor_get_device(struct udev_monitor *udev_monitor);
#endif

139
udev/lib/test-libudev.c
View file

@ -21,6 +21,11 @@
#include <stdio.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/select.h>
#include "libudev.h"
static void log_fn(struct udev *udev,
@ -31,9 +36,49 @@ static void log_fn(struct udev *udev,
vprintf(format, args);
}
static int devlinks_cb(struct udev_device *udev_device, const char *value, void *data)
static int print_devlinks_cb(struct udev_device *udev_device, const char *value, void *data)
{
printf("link: %s\n", value);
printf("link: '%s'\n", value);
return 0;
}
static int print_properties_cb(struct udev_device *udev_device, const char *key, const char *value, void *data)
{
printf("property: '%s=%s'\n", key, value);
return 0;
}
static void print_device(struct udev_device *device)
{
const char *str;
int count;
printf("*** device: %p ***\n", device);
str = udev_device_get_devpath(device);
printf("devpath: '%s'\n", str);
str = udev_device_get_subsystem(device);
printf("subsystem: '%s'\n", str);
str = udev_device_get_devname(device);
printf("devname: '%s'\n", str);
count = udev_device_get_devlinks(device, print_devlinks_cb, NULL);
printf("found %i links\n", count);
count = udev_device_get_properties(device, print_properties_cb, NULL);
printf("found %i properties\n", count);
printf("\n");
}
static int test_device(struct udev *udev, const char *devpath)
{
struct udev_device *device;
printf("looking at device: %s\n", devpath);
device = udev_device_new_from_devpath(udev, devpath);
if (device == NULL) {
printf("no device\n");
return -1;
}
print_device(device);
udev_device_unref(device);
return 0;
}
@ -41,28 +86,79 @@ static int devices_enum_cb(struct udev *udev,
const char *devpath, const char *subsystem, const char *name,
void *data)
{
printf("device: %s (%s) %s\n", devpath, subsystem, name);
printf("device: '%s' (%s) '%s'\n", devpath, subsystem, name);
return 0;
}
static int properties_cb(struct udev_device *udev_device, const char *key, const char *value, void *data)
static int test_enumerate(struct udev *udev, const char *subsystem)
{
printf("property: %s=%s\n", key, value);
int count;
count = udev_devices_enumerate(udev, subsystem, devices_enum_cb, NULL);
printf("found %i devices\n\n", count);
return count;
}
static int test_monitor(struct udev *udev, const char *socket_path)
{
struct udev_monitor *udev_monitor;
fd_set readfds;
int fd;
udev_monitor = udev_monitor_new_from_socket(udev, socket_path);
if (udev_monitor == NULL) {
printf("no socket\n");
return -1;
}
fd = udev_monitor_get_fd(udev_monitor);
FD_ZERO(&readfds);
while (1) {
struct udev_device *device;
int fdcount;
FD_SET(STDIN_FILENO, &readfds);
FD_SET(fd, &readfds);
printf("waiting for events on %s, press ENTER to exit\n", socket_path);
fdcount = select(fd+1, &readfds, NULL, NULL, NULL);
printf("select fd count: %i\n", fdcount);
if (FD_ISSET(fd, &readfds)) {
device = udev_monitor_get_device(udev_monitor);
if (device == NULL) {
printf("no device from socket\n");
continue;
}
print_device(device);
udev_device_unref(device);
}
if (FD_ISSET(STDIN_FILENO, &readfds)) {
printf("exiting loop\n");
break;
}
}
udev_monitor_unref(udev_monitor);
return 0;
}
int main(int argc, char *argv[], char *envp[])
{
struct udev *udev;
struct udev_device *device;
const char *str;
const char *devpath = "/devices/virtual/mem/null";
const char *subsystem = NULL;
const char *socket = "@/org/kernel/udev/monitor";
const char *str;
if (argv[1] != NULL) {
devpath = argv[1];
if (argv[2] != NULL)
subsystem = argv[2];
if (argv[3] != NULL)
socket = argv[3];
}
udev = udev_new();
@ -75,32 +171,13 @@ int main(int argc, char *argv[], char *envp[])
printf("set log: %p\n", log_fn);
str = udev_get_sys_path(udev);
printf("sys_path: %s\n", str);
printf("sys_path: '%s'\n", str);
str = udev_get_dev_path(udev);
printf("dev_path: %s\n", str);
printf("dev_path: '%s'\n", str);
printf("looking at device: %s\n", devpath);
device = udev_device_new_from_devpath(udev, devpath);
printf("device: %p\n", device);
if (device == NULL) {
printf("no device\n");
return 1;
}
str = udev_device_get_devpath(device);
printf("devpath: %s\n", str);
str = udev_device_get_subsystem(device);
printf("subsystem: %s\n", str);
str = udev_device_get_devname(device);
printf("devname: %s\n", str);
udev_device_get_devlinks(device, devlinks_cb, NULL);
udev_device_get_properties(device, properties_cb, NULL);
udev_device_unref(device);
if (subsystem == NULL)
printf("enumerating devices from all subsystems\n");
else
printf("enumerating devices from subsystem: %s\n", subsystem);
udev_devices_enumerate(udev, subsystem, devices_enum_cb, NULL);
test_device(udev, devpath);
test_enumerate(udev, subsystem);
test_monitor(udev, socket);
udev_unref(udev);
return 0;