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udevd: create standard symlinks and handle /lib/udev/devices

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This commit is contained in:
Kay Sievers 2010-05-20 09:04:26 +02:00
parent c1332ae898
commit cb9a0eeeab
3 changed files with 156 additions and 24 deletions
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3
libudev/libudev-private.h
View File

@ -227,12 +227,15 @@ static inline void udev_selinux_init(struct udev *udev) {}
static inline void udev_selinux_exit(struct udev *udev) {}
static inline void udev_selinux_lsetfilecon(struct udev *udev, const char *file, unsigned int mode) {}
static inline void udev_selinux_setfscreatecon(struct udev *udev, const char *file, unsigned int mode) {}
static inline void udev_selinux_setfscreateconat(struct udev *udev, int dirfd, const char *file, unsigned int mode) {}
static inline void udev_selinux_resetfscreatecon(struct udev *udev) {}
#else
void udev_selinux_init(struct udev *udev);
void udev_selinux_exit(struct udev *udev);
void udev_selinux_lsetfilecon(struct udev *udev, const char *file, unsigned int mode);
void udev_selinux_setfscreatecon(struct udev *udev, const char *file, unsigned int mode);
void udev_selinux_setfscreateconat(struct udev *udev, int dirfd, const char *file, unsigned int mode);
void udev_selinux_resetfscreatecon(struct udev *udev);
#endif
#endif

28
libudev/libudev-selinux-private.c
View File

@ -53,7 +53,7 @@ void udev_selinux_lsetfilecon(struct udev *udev, const char *file, unsigned int
if (matchpathcon(file, mode, &scontext) < 0) {
err(udev, "matchpathcon(%s) failed\n", file);
return;
}
}
if (lsetfilecon(file, scontext) < 0)
err(udev, "setfilecon %s failed: %m\n", file);
freecon(scontext);
@ -65,6 +65,7 @@ void udev_selinux_setfscreatecon(struct udev *udev, const char *file, unsigned i
if (!selinux_enabled)
return;
if (matchpathcon(file, mode, &scontext) < 0) {
err(udev, "matchpathcon(%s) failed\n", file);
return;
@ -81,3 +82,28 @@ void udev_selinux_resetfscreatecon(struct udev *udev)
if (setfscreatecon(selinux_prev_scontext) < 0)
err(udev, "setfscreatecon failed: %m\n");
}
void udev_selinux_setfscreateconat(struct udev *udev, int dirfd, const char *file, unsigned int mode)
{
char filename[UTIL_PATH_SIZE];
if (!selinux_enabled)
return;
/* resolve relative filename */
if (file[0] != '/') {
char procfd[UTIL_PATH_SIZE];
char target[UTIL_PATH_SIZE];
ssize_t len;
snprintf(procfd, sizeof(procfd), "/proc/%u/fd/%u", getpid(), dirfd);
len = readlink(procfd, target, sizeof(target));
if (len <= 0 || len == sizeof(target))
return;
target[len] = '\0';
util_strscpyl(filename, sizeof(filename), target, "/", file, NULL);
file = filename;
}
udev_selinux_setfscreatecon(udev, file, mode);
}

149
udev/udevd.c
View File

@ -449,29 +449,6 @@ static void worker_kill(struct udev *udev, int retain)
}
}
static int mem_size_mb(void)
{
FILE *f;
char buf[4096];
long int memsize = -1;
f = fopen("/proc/meminfo", "r");
if (f == NULL)
return -1;
while (fgets(buf, sizeof(buf), f) != NULL) {
long int value;
if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
memsize = value / 1024;
break;
}
}
fclose(f);
return memsize;
}
/* lookup event for identical, parent, child device */
static bool is_devpath_busy(struct event *event)
{
@ -768,6 +745,130 @@ static void handle_signal(struct udev *udev, int signo)
}
}
static int copy_dir(struct udev *udev, DIR *dir_from, DIR *dir_to, int maxdepth)
{
struct dirent *dent;
for (dent = readdir(dir_from); dent != NULL; dent = readdir(dir_from)) {
struct stat stats;
if (dent->d_name[0] == '.')
continue;
if (fstatat(dirfd(dir_from), dent->d_name, &stats, AT_SYMLINK_NOFOLLOW) != 0)
continue;
if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, stats.st_mode & 0777);
if (mknodat(dirfd(dir_to), dent->d_name, stats.st_mode, stats.st_rdev) == 0) {
fchmodat(dirfd(dir_to), dent->d_name, stats.st_mode & 0777, 0);
fchownat(dirfd(dir_to), dent->d_name, stats.st_uid, stats.st_gid, 0);
} else {
utimensat(dirfd(dir_to), dent->d_name, NULL, 0);
}
udev_selinux_resetfscreatecon(udev);
} else if (S_ISLNK(stats.st_mode)) {
char target[UTIL_PATH_SIZE];
ssize_t len;
len = readlinkat(dirfd(dir_from), dent->d_name, target, sizeof(target));
if (len <= 0 || len == (ssize_t)sizeof(target))
continue;
target[len] = '\0';
udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, S_IFLNK);
if (symlinkat(target, dirfd(dir_to), dent->d_name) < 0 && errno == EEXIST)
utimensat(dirfd(dir_to), dent->d_name, NULL, AT_SYMLINK_NOFOLLOW);
udev_selinux_resetfscreatecon(udev);
} else if (S_ISDIR(stats.st_mode)) {
DIR *dir2_from, *dir2_to;
if (maxdepth == 0)
continue;
udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, S_IFDIR|0755);
mkdirat(dirfd(dir_to), dent->d_name, 0755);
udev_selinux_resetfscreatecon(udev);
dir2_to = fdopendir(openat(dirfd(dir_to), dent->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC));
if (dir2_to == NULL)
continue;
dir2_from = fdopendir(openat(dirfd(dir_from), dent->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC));
if (dir2_from == NULL) {
closedir(dir2_to);
continue;
}
copy_dir(udev, dir2_from, dir2_to, maxdepth-1);
closedir(dir2_to);
closedir(dir2_from);
}
}
return 0;
}
static void prepare_dev(struct udev *udev)
{
struct stdlinks {
const char *link;
const char *target;
};
static const struct stdlinks stdlinks[] = {
{ "core", "/proc/kcore" },
{ "fd", "/proc/fd" },
{ "stdin", "/proc/self/fd/0" },
{ "stdout", "/proc/self/fd/1" },
{ "stderr", "/proc/self/fd/2" },
};
unsigned int i;
DIR *dir_from, *dir_to;
dir_to = opendir(udev_get_dev_path(udev));
if (dir_to == NULL)
return;
/* create standard symlinks to /proc */
for (i = 0; i < ARRAY_SIZE(stdlinks); i++) {
udev_selinux_setfscreateconat(udev, dirfd(dir_to), stdlinks[i].link, S_IFLNK);
if (symlinkat(stdlinks[i].target, dirfd(dir_to), stdlinks[i].link) < 0 && errno == EEXIST)
utimensat(dirfd(dir_to), stdlinks[i].link, NULL, AT_SYMLINK_NOFOLLOW);
udev_selinux_resetfscreatecon(udev);
}
/* copy content from /lib/udev/devices to /dev */
dir_from = opendir(LIBEXECDIR "/devices");
if (dir_from != NULL) {
copy_dir(udev, dir_from, dir_to, 8);
closedir(dir_from);
}
closedir(dir_to);
}
static int mem_size_mb(void)
{
FILE *f;
char buf[4096];
long int memsize = -1;
f = fopen("/proc/meminfo", "r");
if (f == NULL)
return -1;
while (fgets(buf, sizeof(buf), f) != NULL) {
long int value;
if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
memsize = value / 1024;
break;
}
}
fclose(f);
return memsize;
}
int main(int argc, char *argv[])
{
struct udev *udev;
@ -858,6 +959,8 @@ int main(int argc, char *argv[])
if (write(STDERR_FILENO, 0, 0) < 0)
dup2(fd, STDERR_FILENO);
prepare_dev(udev);
/* init control socket, bind() ensures, that only one udevd instance is running */
udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
if (udev_ctrl == NULL) {