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platform_system_core/init/devices.c
Benoit Goby d2278638d6 init: Add symlinks to USB character devices 
Since we now support USB host mode, devices might get a different device
file depending if other devices are connected on the host port. This
patch creates symlinks to USB character devices that depend on the port
devices are connected to, but not on the order they have been probed.
(e.g. /dev/usb/tty2-1:1.0 -> /dev/ttyUSB0)

Change-Id: I285bcc2d59446fbff8a7abbe39c21781f3bb4bd3
2010-08-10 15:13:07 -07:00

744 lines
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/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <dirent.h>
#include <unistd.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <linux/netlink.h>
#include <private/android_filesystem_config.h>
#include <sys/time.h>
#include <asm/page.h>
#include <sys/wait.h>
#include "devices.h"
#include "util.h"
#include "log.h"
#include "list.h"
#define SYSFS_PREFIX "/sys"
#define FIRMWARE_DIR "/etc/firmware"
static int device_fd = -1;
struct uevent {
const char *action;
const char *path;
const char *subsystem;
const char *firmware;
const char *partition_name;
int partition_num;
int major;
int minor;
};
static int open_uevent_socket(void)
{
struct sockaddr_nl addr;
int sz = 64*1024; // XXX larger? udev uses 16MB!
int on = 1;
int s;
memset(&addr, 0, sizeof(addr));
addr.nl_family = AF_NETLINK;
addr.nl_pid = getpid();
addr.nl_groups = 0xffffffff;
s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
if(s < 0)
return -1;
setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
close(s);
return -1;
}
return s;
}
struct perms_ {
char *name;
mode_t perm;
unsigned int uid;
unsigned int gid;
unsigned short prefix;
};
struct perm_node {
struct perms_ dp;
struct listnode plist;
};
static list_declare(dev_perms);
/*
* Permission override when in emulator mode, must be parsed before
* system properties is initalized.
*/
int add_dev_perms(const char *name, mode_t perm, unsigned int uid,
unsigned int gid, unsigned short prefix) {
int size;
char *tmp = 0;
struct perm_node *node = malloc(sizeof (struct perm_node));
if (!node)
return -ENOMEM;
size = strlen(name) + 1;
if ((node->dp.name = malloc(size)) == NULL)
return -ENOMEM;
memcpy(node->dp.name, name, size);
node->dp.perm = perm;
node->dp.uid = uid;
node->dp.gid = gid;
node->dp.prefix = prefix;
list_add_tail(&dev_perms, &node->plist);
return 0;
}
static int get_device_perm_inner(struct perms_ *perms, const char *path,
unsigned *uid, unsigned *gid, mode_t *perm)
{
int i;
for(i = 0; perms[i].name; i++) {
if(perms[i].prefix) {
if(strncmp(path, perms[i].name, strlen(perms[i].name)))
continue;
} else {
if(strcmp(path, perms[i].name))
continue;
}
*uid = perms[i].uid;
*gid = perms[i].gid;
*perm = perms[i].perm;
return 0;
}
return -1;
}
/* First checks for emulator specific permissions specified in /proc/cmdline. */
static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
{
mode_t perm;
struct listnode *node;
struct perm_node *perm_node;
struct perms_ *dp;
/* search the perms list in reverse so that ueventd.$hardware can
* override ueventd.rc
*/
list_for_each_reverse(node, &dev_perms) {
perm_node = node_to_item(node, struct perm_node, plist);
dp = &perm_node->dp;
if (dp->prefix) {
if (strncmp(path, dp->name, strlen(dp->name)))
continue;
} else {
if (strcmp(path, dp->name))
continue;
}
*uid = dp->uid;
*gid = dp->gid;
return dp->perm;
}
/* Default if nothing found. */
*uid = 0;
*gid = 0;
return 0600;
}
static void make_device(const char *path, int block, int major, int minor)
{
unsigned uid;
unsigned gid;
mode_t mode;
dev_t dev;
if(major > 255 || minor > 255)
return;
mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
dev = (major << 8) | minor;
/* Temporarily change egid to avoid race condition setting the gid of the
* device node. Unforunately changing the euid would prevent creation of
* some device nodes, so the uid has to be set with chown() and is still
* racy. Fixing the gid race at least fixed the issue with system_server
* opening dynamic input devices under the AID_INPUT gid. */
setegid(gid);
mknod(path, mode, dev);
chown(path, uid, -1);
setegid(AID_ROOT);
}
#if LOG_UEVENTS
static inline suseconds_t get_usecs(void)
{
struct timeval tv;
gettimeofday(&tv, 0);
return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
}
#define log_event_print(x...) INFO(x)
#else
#define log_event_print(fmt, args...) do { } while (0)
#define get_usecs() 0
#endif
static void parse_event(const char *msg, struct uevent *uevent)
{
uevent->action = "";
uevent->path = "";
uevent->subsystem = "";
uevent->firmware = "";
uevent->major = -1;
uevent->minor = -1;
uevent->partition_name = NULL;
uevent->partition_num = -1;
/* currently ignoring SEQNUM */
while(*msg) {
if(!strncmp(msg, "ACTION=", 7)) {
msg += 7;
uevent->action = msg;
} else if(!strncmp(msg, "DEVPATH=", 8)) {
msg += 8;
uevent->path = msg;
} else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
msg += 10;
uevent->subsystem = msg;
} else if(!strncmp(msg, "FIRMWARE=", 9)) {
msg += 9;
uevent->firmware = msg;
} else if(!strncmp(msg, "MAJOR=", 6)) {
msg += 6;
uevent->major = atoi(msg);
} else if(!strncmp(msg, "MINOR=", 6)) {
msg += 6;
uevent->minor = atoi(msg);
} else if(!strncmp(msg, "PARTN=", 6)) {
msg += 6;
uevent->partition_num = atoi(msg);
} else if(!strncmp(msg, "PARTNAME=", 9)) {
msg += 9;
uevent->partition_name = msg;
}
/* advance to after the next \0 */
while(*msg++)
;
}
log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
uevent->action, uevent->path, uevent->subsystem,
uevent->firmware, uevent->major, uevent->minor);
}
static char **get_character_device_symlinks(struct uevent *uevent)
{
const char *parent;
char *slash;
char **links;
int link_num = 0;
int width;
if (strncmp(uevent->path, "/devices/platform/", 18))
return NULL;
links = malloc(sizeof(char *) * 2);
if (!links)
return NULL;
memset(links, 0, sizeof(char *) * 2);
/* skip "/devices/platform/<driver>" */
parent = strchr(uevent->path + 18, '/');
if (!*parent)
goto err;
if (!strncmp(parent, "/usb", 4)) {
/* skip root hub name and device. use device interface */
while (*++parent && *parent != '/');
if (*parent)
while (*++parent && *parent != '/');
if (!*parent)
goto err;
slash = strchr(++parent, '/');
if (!slash)
goto err;
width = slash - parent;
if (width <= 0)
goto err;
if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
link_num++;
else
links[link_num] = NULL;
mkdir("/dev/usb", 0755);
}
else {
goto err;
}
return links;
err:
free(links);
return NULL;
}
static char **parse_platform_block_device(struct uevent *uevent)
{
const char *driver;
const char *path;
char *slash;
int width;
char buf[256];
char link_path[256];
int fd;
int link_num = 0;
int ret;
char *p;
unsigned int size;
struct stat info;
char **links = malloc(sizeof(char *) * 4);
if (!links)
return NULL;
memset(links, 0, sizeof(char *) * 4);
/* Drop "/devices/platform/" */
path = uevent->path;
driver = path + 18;
slash = strchr(driver, '/');
if (!slash)
goto err;
width = slash - driver;
if (width <= 0)
goto err;
snprintf(link_path, sizeof(link_path), "/dev/block/platform/%.*s",
width, driver);
if (uevent->partition_name) {
p = strdup(uevent->partition_name);
sanitize(p);
if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
link_num++;
else
links[link_num] = NULL;
free(p);
}
if (uevent->partition_num >= 0) {
if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
link_num++;
else
links[link_num] = NULL;
}
slash = strrchr(path, '/');
if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
link_num++;
else
links[link_num] = NULL;
return links;
err:
free(links);
return NULL;
}
static void handle_device_event(struct uevent *uevent)
{
char devpath[96];
int devpath_ready = 0;
char *base, *name;
char **links = NULL;
int block;
int i;
/* if it's not a /dev device, nothing to do */
if((uevent->major < 0) || (uevent->minor < 0))
return;
/* do we have a name? */
name = strrchr(uevent->path, '/');
if(!name)
return;
name++;
/* too-long names would overrun our buffer */
if(strlen(name) > 64)
return;
/* are we block or char? where should we live? */
if(!strncmp(uevent->subsystem, "block", 5)) {
block = 1;
base = "/dev/block/";
mkdir(base, 0755);
if (!strncmp(uevent->path, "/devices/platform/", 18))
links = parse_platform_block_device(uevent);
} else {
block = 0;
/* this should probably be configurable somehow */
if (!strncmp(uevent->subsystem, "usb", 3)) {
if (!strcmp(uevent->subsystem, "usb")) {
/* This imitates the file system that would be created
* if we were using devfs instead.
* Minors are broken up into groups of 128, starting at "001"
*/
int bus_id = uevent->minor / 128 + 1;
int device_id = uevent->minor % 128 + 1;
/* build directories */
mkdir("/dev/bus", 0755);
mkdir("/dev/bus/usb", 0755);
snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
mkdir(devpath, 0755);
snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
devpath_ready = 1;
} else {
/* ignore other USB events */
return;
}
} else if (!strncmp(uevent->subsystem, "graphics", 8)) {
base = "/dev/graphics/";
mkdir(base, 0755);
} else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
base = "/dev/oncrpc/";
mkdir(base, 0755);
} else if (!strncmp(uevent->subsystem, "adsp", 4)) {
base = "/dev/adsp/";
mkdir(base, 0755);
} else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
base = "/dev/msm_camera/";
mkdir(base, 0755);
} else if(!strncmp(uevent->subsystem, "input", 5)) {
base = "/dev/input/";
mkdir(base, 0755);
} else if(!strncmp(uevent->subsystem, "mtd", 3)) {
base = "/dev/mtd/";
mkdir(base, 0755);
} else if(!strncmp(uevent->subsystem, "sound", 5)) {
base = "/dev/snd/";
mkdir(base, 0755);
} else if(!strncmp(uevent->subsystem, "misc", 4) &&
!strncmp(name, "log_", 4)) {
base = "/dev/log/";
mkdir(base, 0755);
name += 4;
} else
base = "/dev/";
links = get_character_device_symlinks(uevent);
}
if (!devpath_ready)
snprintf(devpath, sizeof(devpath), "%s%s", base, name);
if(!strcmp(uevent->action, "add")) {
make_device(devpath, block, uevent->major, uevent->minor);
if (links) {
for (i = 0; links[i]; i++)
make_link(devpath, links[i]);
}
}
if(!strcmp(uevent->action, "remove")) {
if (links) {
for (i = 0; links[i]; i++)
remove_link(devpath, links[i]);
}
unlink(devpath);
}
if (links) {
for (i = 0; links[i]; i++)
free(links[i]);
free(links);
}
}
static int load_firmware(int fw_fd, int loading_fd, int data_fd)
{
struct stat st;
long len_to_copy;
int ret = 0;
if(fstat(fw_fd, &st) < 0)
return -1;
len_to_copy = st.st_size;
write(loading_fd, "1", 1); /* start transfer */
while (len_to_copy > 0) {
char buf[PAGE_SIZE];
ssize_t nr;
nr = read(fw_fd, buf, sizeof(buf));
if(!nr)
break;
if(nr < 0) {
ret = -1;
break;
}
len_to_copy -= nr;
while (nr > 0) {
ssize_t nw = 0;
nw = write(data_fd, buf + nw, nr);
if(nw <= 0) {
ret = -1;
goto out;
}
nr -= nw;
}
}
out:
if(!ret)
write(loading_fd, "0", 1); /* successful end of transfer */
else
write(loading_fd, "-1", 2); /* abort transfer */
return ret;
}
static void process_firmware_event(struct uevent *uevent)
{
char *root, *loading, *data, *file;
int l, loading_fd, data_fd, fw_fd;
log_event_print("firmware event { '%s', '%s' }\n",
uevent->path, uevent->firmware);
l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
if (l == -1)
return;
l = asprintf(&loading, "%sloading", root);
if (l == -1)
goto root_free_out;
l = asprintf(&data, "%sdata", root);
if (l == -1)
goto loading_free_out;
l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware);
if (l == -1)
goto data_free_out;
loading_fd = open(loading, O_WRONLY);
if(loading_fd < 0)
goto file_free_out;
data_fd = open(data, O_WRONLY);
if(data_fd < 0)
goto loading_close_out;
fw_fd = open(file, O_RDONLY);
if(fw_fd < 0)
goto data_close_out;
if(!load_firmware(fw_fd, loading_fd, data_fd))
log_event_print("firmware copy success { '%s', '%s' }\n", root, file);
else
log_event_print("firmware copy failure { '%s', '%s' }\n", root, file);
close(fw_fd);
data_close_out:
close(data_fd);
loading_close_out:
close(loading_fd);
file_free_out:
free(file);
data_free_out:
free(data);
loading_free_out:
free(loading);
root_free_out:
free(root);
}
static void handle_firmware_event(struct uevent *uevent)
{
pid_t pid;
int status;
int ret;
if(strcmp(uevent->subsystem, "firmware"))
return;
if(strcmp(uevent->action, "add"))
return;
/* we fork, to avoid making large memory allocations in init proper */
pid = fork();
if (!pid) {
process_firmware_event(uevent);
exit(EXIT_SUCCESS);
} else {
do {
ret = waitpid(pid, &status, 0);
} while (ret == -1 && errno == EINTR);
}
}
#define UEVENT_MSG_LEN 1024
void handle_device_fd()
{
for(;;) {
char msg[UEVENT_MSG_LEN+2];
char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
struct iovec iov = {msg, sizeof(msg)};
struct sockaddr_nl snl;
struct msghdr hdr = {&snl, sizeof(snl), &iov, 1, cred_msg, sizeof(cred_msg), 0};
ssize_t n = recvmsg(device_fd, &hdr, 0);
if (n <= 0) {
break;
}
if ((snl.nl_groups != 1) || (snl.nl_pid != 0)) {
/* ignoring non-kernel netlink multicast message */
continue;
}
struct cmsghdr * cmsg = CMSG_FIRSTHDR(&hdr);
if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
/* no sender credentials received, ignore message */
continue;
}
struct ucred * cred = (struct ucred *)CMSG_DATA(cmsg);
if (cred->uid != 0) {
/* message from non-root user, ignore */
continue;
}
if(n >= UEVENT_MSG_LEN) /* overflow -- discard */
continue;
msg[n] = '\0';
msg[n+1] = '\0';
struct uevent uevent;
parse_event(msg, &uevent);
handle_device_event(&uevent);
handle_firmware_event(&uevent);
}
}
/* Coldboot walks parts of the /sys tree and pokes the uevent files
** to cause the kernel to regenerate device add events that happened
** before init's device manager was started
**
** We drain any pending events from the netlink socket every time
** we poke another uevent file to make sure we don't overrun the
** socket's buffer.
*/
static void do_coldboot(DIR *d)
{
struct dirent *de;
int dfd, fd;
dfd = dirfd(d);
fd = openat(dfd, "uevent", O_WRONLY);
if(fd >= 0) {
write(fd, "add\n", 4);
close(fd);
handle_device_fd();
}
while((de = readdir(d))) {
DIR *d2;
if(de->d_type != DT_DIR || de->d_name[0] == '.')
continue;
fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
if(fd < 0)
continue;
d2 = fdopendir(fd);
if(d2 == 0)
close(fd);
else {
do_coldboot(d2);
closedir(d2);
}
}
}
static void coldboot(const char *path)
{
DIR *d = opendir(path);
if(d) {
do_coldboot(d);
closedir(d);
}
}
void device_init(void)
{
suseconds_t t0, t1;
struct stat info;
int fd;
device_fd = open_uevent_socket();
if(device_fd < 0)
return;
fcntl(device_fd, F_SETFD, FD_CLOEXEC);
fcntl(device_fd, F_SETFL, O_NONBLOCK);
if (stat(coldboot_done, &info) < 0) {
t0 = get_usecs();
coldboot("/sys/class");
coldboot("/sys/block");
coldboot("/sys/devices");
t1 = get_usecs();
fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
close(fd);
log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
} else {
log_event_print("skipping coldboot, already done\n");
}
}
int get_device_fd()
{
return device_fd;
}
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