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platform_system_core
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platform_system_core/init/util.c

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/*
* Copyright (C) 2008 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 <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <ctype.h>
#include <errno.h>
#include <time.h>
#include <ftw.h>
#include <selinux/label.h>
#include <selinux/android.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
/* for ANDROID_SOCKET_* */
#include <cutils/sockets.h>
#include <private/android_filesystem_config.h>
#include "init.h"
#include "log.h"
#include "util.h"
/*
* android_name_to_id - returns the integer uid/gid associated with the given
* name, or -1U on error.
*/
static unsigned int android_name_to_id(const char *name)
{
const struct android_id_info *info = android_ids;
unsigned int n;
for (n = 0; n < android_id_count; n++) {
if (!strcmp(info[n].name, name))
return info[n].aid;
}
return -1U;
}
/*
* decode_uid - decodes and returns the given string, which can be either the
* numeric or name representation, into the integer uid or gid. Returns -1U on
* error.
*/
unsigned int decode_uid(const char *s)
{
unsigned int v;
if (!s || *s == '\0')
return -1U;
if (isalpha(s[0]))
return android_name_to_id(s);
errno = 0;
v = (unsigned int) strtoul(s, 0, 0);
if (errno)
return -1U;
return v;
}
/*
* create_socket - creates a Unix domain socket in ANDROID_SOCKET_DIR
* ("/dev/socket") as dictated in init.rc. This socket is inherited by the
* daemon. We communicate the file descriptor's value via the environment
* variable ANDROID_SOCKET_ENV_PREFIX<name> ("ANDROID_SOCKET_foo").
*/
int create_socket(const char *name, int type, mode_t perm, uid_t uid,
gid_t gid, const char *socketcon)
{
struct sockaddr_un addr;
int fd, ret;
char *filecon;
if (socketcon)
setsockcreatecon(socketcon);
fd = socket(PF_UNIX, type, 0);
if (fd < 0) {
ERROR("Failed to open socket '%s': %s\n", name, strerror(errno));
return -1;
}
if (socketcon)
setsockcreatecon(NULL);
memset(&addr, 0 , sizeof(addr));
addr.sun_family = AF_UNIX;
snprintf(addr.sun_path, sizeof(addr.sun_path), ANDROID_SOCKET_DIR"/%s",
name);
ret = unlink(addr.sun_path);
if (ret != 0 && errno != ENOENT) {
ERROR("Failed to unlink old socket '%s': %s\n", name, strerror(errno));
goto out_close;
}
filecon = NULL;
if (sehandle) {
ret = selabel_lookup(sehandle, &filecon, addr.sun_path, S_IFSOCK);
if (ret == 0)
setfscreatecon(filecon);
}
ret = bind(fd, (struct sockaddr *) &addr, sizeof (addr));
if (ret) {
ERROR("Failed to bind socket '%s': %s\n", name, strerror(errno));
goto out_unlink;
}
setfscreatecon(NULL);
freecon(filecon);
chown(addr.sun_path, uid, gid);
chmod(addr.sun_path, perm);
INFO("Created socket '%s' with mode '%o', user '%d', group '%d'\n",
addr.sun_path, perm, uid, gid);
return fd;
out_unlink:
unlink(addr.sun_path);
out_close:
close(fd);
return -1;
}
/* reads a file, making sure it is terminated with \n \0 */
void *read_file(const char *fn, unsigned *_sz)
{
char *data;
int sz;
int fd;
struct stat sb;
data = 0;
fd = open(fn, O_RDONLY);
if(fd < 0) return 0;
// for security reasons, disallow world-writable
// or group-writable files
if (fstat(fd, &sb) < 0) {
ERROR("fstat failed for '%s'\n", fn);
goto oops;
}
if ((sb.st_mode & (S_IWGRP | S_IWOTH)) != 0) {
ERROR("skipping insecure file '%s'\n", fn);
goto oops;
}
sz = lseek(fd, 0, SEEK_END);
if(sz < 0) goto oops;
if(lseek(fd, 0, SEEK_SET) != 0) goto oops;
data = (char*) malloc(sz + 2);
if(data == 0) goto oops;
if(read(fd, data, sz) != sz) goto oops;
close(fd);
data[sz] = '\n';
data[sz+1] = 0;
if(_sz) *_sz = sz;
return data;
oops:
close(fd);
if(data != 0) free(data);
return 0;
}
#define MAX_MTD_PARTITIONS 16
static struct {
char name[16];
int number;
} mtd_part_map[MAX_MTD_PARTITIONS];
static int mtd_part_count = -1;
static void find_mtd_partitions(void)
{
int fd;
char buf[1024];
char *pmtdbufp;
ssize_t pmtdsize;
int r;
fd = open("/proc/mtd", O_RDONLY);
if (fd < 0)
return;
buf[sizeof(buf) - 1] = '\0';
pmtdsize = read(fd, buf, sizeof(buf) - 1);
pmtdbufp = buf;
while (pmtdsize > 0) {
int mtdnum, mtdsize, mtderasesize;
char mtdname[16];
mtdname[0] = '\0';
mtdnum = -1;
r = sscanf(pmtdbufp, "mtd%d: %x %x %15s",
&mtdnum, &mtdsize, &mtderasesize, mtdname);
if ((r == 4) && (mtdname[0] == '"')) {
char *x = strchr(mtdname + 1, '"');
if (x) {
*x = 0;
}
INFO("mtd partition %d, %s\n", mtdnum, mtdname + 1);
if (mtd_part_count < MAX_MTD_PARTITIONS) {
strcpy(mtd_part_map[mtd_part_count].name, mtdname + 1);
mtd_part_map[mtd_part_count].number = mtdnum;
mtd_part_count++;
} else {
ERROR("too many mtd partitions\n");
}
}
while (pmtdsize > 0 && *pmtdbufp != '\n') {
pmtdbufp++;
pmtdsize--;
}
if (pmtdsize > 0) {
pmtdbufp++;
pmtdsize--;
}
}
close(fd);
}
int mtd_name_to_number(const char *name)
{
int n;
if (mtd_part_count < 0) {
mtd_part_count = 0;
find_mtd_partitions();
}
for (n = 0; n < mtd_part_count; n++) {
if (!strcmp(name, mtd_part_map[n].name)) {
return mtd_part_map[n].number;
}
}
return -1;
}
/*
* gettime() - returns the time in seconds of the system's monotonic clock or
* zero on error.
*/
time_t gettime(void)
{
struct timespec ts;
int ret;
ret = clock_gettime(CLOCK_MONOTONIC, &ts);
if (ret < 0) {
ERROR("clock_gettime(CLOCK_MONOTONIC) failed: %s\n", strerror(errno));
return 0;
}
return ts.tv_sec;
}
int mkdir_recursive(const char *pathname, mode_t mode)
{
char buf[128];
const char *slash;
const char *p = pathname;
int width;
int ret;
struct stat info;
while ((slash = strchr(p, '/')) != NULL) {
width = slash - pathname;
p = slash + 1;
if (width < 0)
break;
if (width == 0)
continue;
if ((unsigned int)width > sizeof(buf) - 1) {
ERROR("path too long for mkdir_recursive\n");
return -1;
}
memcpy(buf, pathname, width);
buf[width] = 0;
if (stat(buf, &info) != 0) {
ret = make_dir(buf, mode);
if (ret && errno != EEXIST)
return ret;
}
}
ret = make_dir(pathname, mode);
if (ret && errno != EEXIST)
return ret;
return 0;
}
/*
* replaces any unacceptable characters with '_', the
* length of the resulting string is equal to the input string
*/
void sanitize(char *s)
{
const char* accept =
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"0123456789"
"_-.";
if (!s)
return;
while (*s) {
s += strspn(s, accept);
if (*s) *s++ = '_';
}
}
void make_link(const char *oldpath, const char *newpath)
{
int ret;
char buf[256];
char *slash;
int width;
slash = strrchr(newpath, '/');
if (!slash)
return;
width = slash - newpath;
if (width <= 0 || width > (int)sizeof(buf) - 1)
return;
memcpy(buf, newpath, width);
buf[width] = 0;
ret = mkdir_recursive(buf, 0755);
if (ret)
ERROR("Failed to create directory %s: %s (%d)\n", buf, strerror(errno), errno);
ret = symlink(oldpath, newpath);
if (ret && errno != EEXIST)
ERROR("Failed to symlink %s to %s: %s (%d)\n", oldpath, newpath, strerror(errno), errno);
}
void remove_link(const char *oldpath, const char *newpath)
{
char path[256];
ssize_t ret;
ret = readlink(newpath, path, sizeof(path) - 1);
if (ret <= 0)
return;
path[ret] = 0;
if (!strcmp(path, oldpath))
unlink(newpath);
}
int wait_for_file(const char *filename, int timeout)
{
struct stat info;
time_t timeout_time = gettime() + timeout;
int ret = -1;
while (gettime() < timeout_time && ((ret = stat(filename, &info)) < 0))
usleep(10000);
return ret;
}
void open_devnull_stdio(void)
{
int fd;
static const char *name = "/dev/__null__";
if (mknod(name, S_IFCHR | 0600, (1 << 8) | 3) == 0) {
fd = open(name, O_RDWR);
unlink(name);
if (fd >= 0) {
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
if (fd > 2) {
close(fd);
}
return;
}
}
exit(1);
}
void get_hardware_name(char *hardware, unsigned int *revision)
{
const char *cpuinfo = "/proc/cpuinfo";
char *data = NULL;
size_t len = 0, limit = 1024;
int fd, n;
char *x, *hw, *rev;
/* Hardware string was provided on kernel command line */
if (hardware[0])
return;
fd = open(cpuinfo, O_RDONLY);
if (fd < 0) return;
for (;;) {
x = realloc(data, limit);
if (!x) {
ERROR("Failed to allocate memory to read %s\n", cpuinfo);
goto done;
}
data = x;
n = read(fd, data + len, limit - len);
if (n < 0) {
ERROR("Failed reading %s: %s (%d)\n", cpuinfo, strerror(errno), errno);
goto done;
}
len += n;
if (len < limit)
break;
/* We filled the buffer, so increase size and loop to read more */
limit *= 2;
}
data[len] = 0;
hw = strstr(data, "\nHardware");
rev = strstr(data, "\nRevision");
if (hw) {
x = strstr(hw, ": ");
if (x) {
x += 2;
n = 0;
while (*x && *x != '\n') {
if (!isspace(*x))
hardware[n++] = tolower(*x);
x++;
if (n == 31) break;
}
hardware[n] = 0;
}
}
if (rev) {
x = strstr(rev, ": ");
if (x) {
*revision = strtoul(x + 2, 0, 16);
}
}
done:
close(fd);
free(data);
}
void import_kernel_cmdline(int in_qemu,
void (*import_kernel_nv)(char *name, int in_qemu))
{
char cmdline[2048];
char *ptr;
int fd;
fd = open("/proc/cmdline", O_RDONLY);
if (fd >= 0) {
int n = read(fd, cmdline, sizeof(cmdline) - 1);
if (n < 0) n = 0;
/* get rid of trailing newline, it happens */
if (n > 0 && cmdline[n-1] == '\n') n--;
cmdline[n] = 0;
close(fd);
} else {
cmdline[0] = 0;
}
ptr = cmdline;
while (ptr && *ptr) {
char *x = strchr(ptr, ' ');
if (x != 0) *x++ = 0;
import_kernel_nv(ptr, in_qemu);
ptr = x;
}
}
int make_dir(const char *path, mode_t mode)
{
int rc;
char *secontext = NULL;
if (sehandle) {
selabel_lookup(sehandle, &secontext, path, mode);
setfscreatecon(secontext);
}
rc = mkdir(path, mode);
if (secontext) {
int save_errno = errno;
freecon(secontext);
setfscreatecon(NULL);
errno = save_errno;
}
return rc;
}
int restorecon(const char* pathname)
{
return selinux_android_restorecon(pathname, 0);
}
int restorecon_recursive(const char* pathname)
{
return selinux_android_restorecon(pathname, SELINUX_ANDROID_RESTORECON_RECURSE);
}
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