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-rw-r--r--init/util.cpp466
1 files changed, 466 insertions, 0 deletions
diff --git a/init/util.cpp b/init/util.cpp
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index 0000000..20ce806
--- /dev/null
+++ b/init/util.cpp
@@ -0,0 +1,466 @@
+/*
+ * 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>
+
+#include <base/file.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;
+}
+
+bool read_file(const char* path, std::string* content) {
+ content->clear();
+
+ int fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY|O_NOFOLLOW|O_CLOEXEC));
+ if (fd == -1) {
+ return false;
+ }
+
+ // For security reasons, disallow world-writable
+ // or group-writable files.
+ struct stat sb;
+ if (fstat(fd, &sb) == -1) {
+ ERROR("fstat failed for '%s': %s\n", path, strerror(errno));
+ return false;
+ }
+ if ((sb.st_mode & (S_IWGRP | S_IWOTH)) != 0) {
+ ERROR("skipping insecure file '%s'\n", path);
+ return false;
+ }
+
+ bool okay = android::base::ReadFdToString(fd, content);
+ TEMP_FAILURE_RETRY(close(fd));
+ if (okay) {
+ content->append("\n", 1);
+ }
+ return okay;
+}
+
+int write_file(const char* path, const char* content) {
+ int fd = TEMP_FAILURE_RETRY(open(path, O_WRONLY|O_CREAT|O_NOFOLLOW|O_CLOEXEC, 0600));
+ if (fd == -1) {
+ NOTICE("write_file: Unable to open '%s': %s\n", path, strerror(errno));
+ return -1;
+ }
+ int result = android::base::WriteStringToFd(content, fd) ? 0 : -1;
+ if (result == -1) {
+ NOTICE("write_file: Unable to write to '%s': %s\n", path, strerror(errno));
+ }
+ TEMP_FAILURE_RETRY(close(fd));
+ return result;
+}
+
+#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|O_CLOEXEC);
+ 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;
+}
+
+time_t gettime() {
+ timespec now;
+ clock_gettime(CLOCK_MONOTONIC, &now);
+ return now.tv_sec;
+}
+
+uint64_t gettime_ns() {
+ timespec now;
+ clock_gettime(CLOCK_MONOTONIC, &now);
+ return static_cast<uint64_t>(now.tv_sec) * UINT64_C(1000000000) + now.tv_nsec;
+}
+
+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_init(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)
+{
+ // Try to avoid the mknod() call if we can. Since SELinux makes
+ // a /dev/null replacement available for free, let's use it.
+ int fd = open("/sys/fs/selinux/null", O_RDWR);
+ if (fd == -1) {
+ // OOPS, /sys/fs/selinux/null isn't available, likely because
+ // /sys/fs/selinux isn't mounted. Fall back to mknod.
+ 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 == -1) {
+ exit(1);
+ }
+ }
+
+ dup2(fd, 0);
+ dup2(fd, 1);
+ dup2(fd, 2);
+ if (fd > 2) {
+ close(fd);
+ }
+}
+
+void import_kernel_cmdline(bool in_qemu, std::function<void(char*,bool)> import_kernel_nv)
+{
+ char cmdline[2048];
+ char *ptr;
+ int fd;
+
+ fd = open("/proc/cmdline", O_RDONLY | O_CLOEXEC);
+ 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);
+}
generated by cgit v1.1 at 2025-08-16 10:12:36 +0000