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platform_system_core/init/devices.c
Stephen Smalley e2eb69db6d Handle policy reloads within ueventd rather than restarting it. 
Restarting ueventd upon policy reloads has reportedly created
stability problems for some users and could cause events to be lost.
Stop restarting ueventd and instead handle policy reloads within ueventd.

Also stops restarting installd upon policy reloads.

Change-Id: Ic7f310d69a7c420e48fbc974000cf4a5b9ab4a3b
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
2013-07-26 15:39:41 -04:00

937 lines
24 KiB
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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 <stddef.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 <selinux/selinux.h>
#include <selinux/label.h>
#include <selinux/android.h>
#include <selinux/avc.h>
#include <private/android_filesystem_config.h>
#include <sys/time.h>
#include <asm/page.h>
#include <sys/wait.h>
#include <cutils/list.h>
#include <cutils/uevent.h>
#include "devices.h"
#include "util.h"
#include "log.h"
#define SYSFS_PREFIX "/sys"
#define FIRMWARE_DIR1 "/etc/firmware"
#define FIRMWARE_DIR2 "/vendor/firmware"
#define FIRMWARE_DIR3 "/firmware/image"
extern struct selabel_handle *sehandle;
static int device_fd = -1;
struct uevent {
const char *action;
const char *path;
const char *subsystem;
const char *firmware;
const char *partition_name;
const char *device_name;
int partition_num;
int major;
int minor;
};
struct perms_ {
char *name;
char *attr;
mode_t perm;
unsigned int uid;
unsigned int gid;
unsigned short prefix;
};
struct perm_node {
struct perms_ dp;
struct listnode plist;
};
struct platform_node {
char *name;
char *path;
int path_len;
struct listnode list;
};
static list_declare(sys_perms);
static list_declare(dev_perms);
static list_declare(platform_names);
int add_dev_perms(const char *name, const char *attr,
mode_t perm, unsigned int uid, unsigned int gid,
unsigned short prefix) {
struct perm_node *node = calloc(1, sizeof(*node));
if (!node)
return -ENOMEM;
node->dp.name = strdup(name);
if (!node->dp.name)
return -ENOMEM;
if (attr) {
node->dp.attr = strdup(attr);
if (!node->dp.attr)
return -ENOMEM;
}
node->dp.perm = perm;
node->dp.uid = uid;
node->dp.gid = gid;
node->dp.prefix = prefix;
if (attr)
list_add_tail(&sys_perms, &node->plist);
else
list_add_tail(&dev_perms, &node->plist);
return 0;
}
void fixup_sys_perms(const char *upath)
{
char buf[512];
struct listnode *node;
struct perms_ *dp;
char *secontext;
/* upaths omit the "/sys" that paths in this list
* contain, so we add 4 when comparing...
*/
list_for_each(node, &sys_perms) {
dp = &(node_to_item(node, struct perm_node, plist))->dp;
if (dp->prefix) {
if (strncmp(upath, dp->name + 4, strlen(dp->name + 4)))
continue;
} else {
if (strcmp(upath, dp->name + 4))
continue;
}
if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
return;
sprintf(buf,"/sys%s/%s", upath, dp->attr);
INFO("fixup %s %d %d 0%o\n", buf, dp->uid, dp->gid, dp->perm);
chown(buf, dp->uid, dp->gid);
chmod(buf, dp->perm);
if (sehandle) {
secontext = NULL;
selabel_lookup(sehandle, &secontext, buf, 0);
if (secontext) {
setfilecon(buf, secontext);
freecon(secontext);
}
}
}
}
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,
const char *upath,
int block, int major, int minor)
{
unsigned uid;
unsigned gid;
mode_t mode;
dev_t dev;
char *secontext = NULL;
mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
if (sehandle) {
selabel_lookup(sehandle, &secontext, path, mode);
setfscreatecon(secontext);
}
dev = makedev(major, 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 (secontext) {
freecon(secontext);
setfscreatecon(NULL);
}
}
static void add_platform_device(const char *path)
{
int path_len = strlen(path);
struct listnode *node;
struct platform_node *bus;
const char *name = path;
if (!strncmp(path, "/devices/", 9)) {
name += 9;
if (!strncmp(name, "platform/", 9))
name += 9;
}
list_for_each_reverse(node, &platform_names) {
bus = node_to_item(node, struct platform_node, list);
if ((bus->path_len < path_len) &&
(path[bus->path_len] == '/') &&
!strncmp(path, bus->path, bus->path_len))
/* subdevice of an existing platform, ignore it */
return;
}
INFO("adding platform device %s (%s)\n", name, path);
bus = calloc(1, sizeof(struct platform_node));
bus->path = strdup(path);
bus->path_len = path_len;
bus->name = bus->path + (name - path);
list_add_tail(&platform_names, &bus->list);
}
/*
* given a path that may start with a platform device, find the length of the
* platform device prefix. If it doesn't start with a platform device, return
* 0.
*/
static struct platform_node *find_platform_device(const char *path)
{
int path_len = strlen(path);
struct listnode *node;
struct platform_node *bus;
list_for_each_reverse(node, &platform_names) {
bus = node_to_item(node, struct platform_node, list);
if ((bus->path_len < path_len) &&
(path[bus->path_len] == '/') &&
!strncmp(path, bus->path, bus->path_len))
return bus;
}
return NULL;
}
static void remove_platform_device(const char *path)
{
struct listnode *node;
struct platform_node *bus;
list_for_each_reverse(node, &platform_names) {
bus = node_to_item(node, struct platform_node, list);
if (!strcmp(path, bus->path)) {
INFO("removing platform device %s\n", bus->name);
free(bus->path);
list_remove(node);
free(bus);
return;
}
}
}
#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;
uevent->device_name = NULL;
/* 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;
} else if(!strncmp(msg, "DEVNAME=", 8)) {
msg += 8;
uevent->device_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;
struct platform_node *pdev;
pdev = find_platform_device(uevent->path);
if (!pdev)
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 + pdev->path_len, '/');
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 *device;
struct platform_node *pdev;
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;
pdev = find_platform_device(uevent->path);
if (!pdev)
return NULL;
device = pdev->name;
char **links = malloc(sizeof(char *) * 4);
if (!links)
return NULL;
memset(links, 0, sizeof(char *) * 4);
INFO("found platform device %s\n", device);
snprintf(link_path, sizeof(link_path), "/dev/block/platform/%s", device);
if (uevent->partition_name) {
p = strdup(uevent->partition_name);
sanitize(p);
if (strcmp(uevent->partition_name, p))
NOTICE("Linking partition '%s' as '%s'\n", uevent->partition_name, 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(uevent->path, '/');
if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
link_num++;
else
links[link_num] = NULL;
return links;
}
static void handle_device(const char *action, const char *devpath,
const char *path, int block, int major, int minor, char **links)
{
int i;
if(!strcmp(action, "add")) {
make_device(devpath, path, block, major, minor);
if (links) {
for (i = 0; links[i]; i++)
make_link(devpath, links[i]);
}
}
if(!strcmp(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 void handle_platform_device_event(struct uevent *uevent)
{
const char *path = uevent->path;
if (!strcmp(uevent->action, "add"))
add_platform_device(path);
else if (!strcmp(uevent->action, "remove"))
remove_platform_device(path);
}
static const char *parse_device_name(struct uevent *uevent, unsigned int len)
{
const char *name;
/* if it's not a /dev device, nothing else to do */
if((uevent->major < 0) || (uevent->minor < 0))
return NULL;
/* do we have a name? */
name = strrchr(uevent->path, '/');
if(!name)
return NULL;
name++;
/* too-long names would overrun our buffer */
if(strlen(name) > len)
return NULL;
return name;
}
static void handle_block_device_event(struct uevent *uevent)
{
const char *base = "/dev/block/";
const char *name;
char devpath[96];
char **links = NULL;
name = parse_device_name(uevent, 64);
if (!name)
return;
snprintf(devpath, sizeof(devpath), "%s%s", base, name);
make_dir(base, 0755);
if (!strncmp(uevent->path, "/devices/", 9))
links = parse_platform_block_device(uevent);
handle_device(uevent->action, devpath, uevent->path, 1,
uevent->major, uevent->minor, links);
}
static void handle_generic_device_event(struct uevent *uevent)
{
char *base;
const char *name;
char devpath[96] = {0};
char **links = NULL;
name = parse_device_name(uevent, 64);
if (!name)
return;
if (!strncmp(uevent->subsystem, "usb", 3)) {
if (!strcmp(uevent->subsystem, "usb")) {
if (uevent->device_name) {
/*
* create device node provided by kernel if present
* see drivers/base/core.c
*/
char *p = devpath;
snprintf(devpath, sizeof(devpath), "/dev/%s", uevent->device_name);
/* skip leading /dev/ */
p += 5;
/* build directories */
while (*p) {
if (*p == '/') {
*p = 0;
make_dir(devpath, 0755);
*p = '/';
}
p++;
}
}
else {
/* 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 */
make_dir("/dev/bus", 0755);
make_dir("/dev/bus/usb", 0755);
snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
make_dir(devpath, 0755);
snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
}
} else {
/* ignore other USB events */
return;
}
} else if (!strncmp(uevent->subsystem, "graphics", 8)) {
base = "/dev/graphics/";
make_dir(base, 0755);
} else if (!strncmp(uevent->subsystem, "drm", 3)) {
base = "/dev/dri/";
make_dir(base, 0755);
} else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
base = "/dev/oncrpc/";
make_dir(base, 0755);
} else if (!strncmp(uevent->subsystem, "adsp", 4)) {
base = "/dev/adsp/";
make_dir(base, 0755);
} else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
base = "/dev/msm_camera/";
make_dir(base, 0755);
} else if(!strncmp(uevent->subsystem, "input", 5)) {
base = "/dev/input/";
make_dir(base, 0755);
} else if(!strncmp(uevent->subsystem, "mtd", 3)) {
base = "/dev/mtd/";
make_dir(base, 0755);
} else if(!strncmp(uevent->subsystem, "sound", 5)) {
base = "/dev/snd/";
make_dir(base, 0755);
} else if(!strncmp(uevent->subsystem, "misc", 4) &&
!strncmp(name, "log_", 4)) {
base = "/dev/log/";
make_dir(base, 0755);
name += 4;
} else
base = "/dev/";
links = get_character_device_symlinks(uevent);
if (!devpath[0])
snprintf(devpath, sizeof(devpath), "%s%s", base, name);
handle_device(uevent->action, devpath, uevent->path, 0,
uevent->major, uevent->minor, links);
}
static void handle_device_event(struct uevent *uevent)
{
if (!strcmp(uevent->action,"add") || !strcmp(uevent->action, "change"))
fixup_sys_perms(uevent->path);
if (!strncmp(uevent->subsystem, "block", 5)) {
handle_block_device_event(uevent);
} else if (!strncmp(uevent->subsystem, "platform", 8)) {
handle_platform_device_event(uevent);
} else {
handle_generic_device_event(uevent);
}
}
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 int is_booting(void)
{
return access("/dev/.booting", F_OK) == 0;
}
static void process_firmware_event(struct uevent *uevent)
{
char *root, *loading, *data, *file1 = NULL, *file2 = NULL, *file3 = NULL;
int l, loading_fd, data_fd, fw_fd;
int booting = is_booting();
INFO("firmware: loading '%s' for '%s'\n",
uevent->firmware, uevent->path);
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(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
if (l == -1)
goto data_free_out;
l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
if (l == -1)
goto data_free_out;
l = asprintf(&file3, FIRMWARE_DIR3"/%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;
try_loading_again:
fw_fd = open(file1, O_RDONLY);
if(fw_fd < 0) {
fw_fd = open(file2, O_RDONLY);
if (fw_fd < 0) {
fw_fd = open(file3, O_RDONLY);
if (fw_fd < 0) {
if (booting) {
/* If we're not fully booted, we may be missing
* filesystems needed for firmware, wait and retry.
*/
usleep(100000);
booting = is_booting();
goto try_loading_again;
}
INFO("firmware: could not open '%s' %d\n", uevent->firmware, errno);
write(loading_fd, "-1", 2);
goto data_close_out;
}
}
}
if(!load_firmware(fw_fd, loading_fd, data_fd))
INFO("firmware: copy success { '%s', '%s' }\n", root, uevent->firmware);
else
INFO("firmware: copy failure { '%s', '%s' }\n", root, uevent->firmware);
close(fw_fd);
data_close_out:
close(data_fd);
loading_close_out:
close(loading_fd);
file_free_out:
free(file1);
free(file2);
free(file3);
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 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);
}
}
#define UEVENT_MSG_LEN 1024
void handle_device_fd()
{
char msg[UEVENT_MSG_LEN+2];
int n;
while ((n = uevent_kernel_multicast_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) {
if(n >= UEVENT_MSG_LEN) /* overflow -- discard */
continue;
msg[n] = '\0';
msg[n+1] = '\0';
struct uevent uevent;
parse_event(msg, &uevent);
if (sehandle && selinux_status_updated() > 0) {
struct selabel_handle *sehandle2;
sehandle2 = selinux_android_file_context_handle();
if (sehandle2) {
selabel_close(sehandle);
sehandle = sehandle2;
}
}
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;
sehandle = NULL;
if (is_selinux_enabled() > 0) {
sehandle = selinux_android_file_context_handle();
selinux_status_open(true);
}
/* is 256K enough? udev uses 16MB! */
device_fd = uevent_open_socket(256*1024, true);
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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