Utils.cpp - SHIFTPHONES/android_system_vold - Gitiles

 /*
  * Copyright (C) 2015 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 "sehandle.h"
 #include "Utils.h"
 #include "Process.h"

 #include <base/logging.h>
 #include <base/stringprintf.h>
 #include <cutils/fs.h>
 #include <private/android_filesystem_config.h>
 #include <logwrap/logwrap.h>

 #include <fcntl.h>
 #include <linux/fs.h>
 #include <stdlib.h>
 #include <sys/mount.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/wait.h>

 #ifndef UMOUNT_NOFOLLOW
 #define UMOUNT_NOFOLLOW    0x00000008  /* Don't follow symlink on umount */
 #endif

 using android::base::StringPrintf;

 namespace android {
 namespace vold {

 security_context_t sBlkidContext = nullptr;
 security_context_t sBlkidUntrustedContext = nullptr;
 security_context_t sFsckContext = nullptr;
 security_context_t sFsckUntrustedContext = nullptr;

 static const char* kBlkidPath = "/system/bin/blkid";

 status_t CreateDeviceNode(const std::string& path, dev_t dev) {
     const char* cpath = path.c_str();
     status_t res = 0;

     char* secontext = nullptr;
     if (sehandle) {
         if (!selabel_lookup(sehandle, &secontext, cpath, S_IFBLK)) {
             setfscreatecon(secontext);
         }
     }

     mode_t mode = 0660 | S_IFBLK;
     if (mknod(cpath, mode, dev) < 0) {
         if (errno != EEXIST) {
             PLOG(ERROR) << "Failed to create device node for " << major(dev)
                     << ":" << minor(dev) << " at " << path;
             res = -errno;
         }
     }

     if (secontext) {
         setfscreatecon(nullptr);
         freecon(secontext);
     }

     return res;
 }

 status_t DestroyDeviceNode(const std::string& path) {
     const char* cpath = path.c_str();
     if (TEMP_FAILURE_RETRY(unlink(cpath))) {
         return -errno;
     } else {
         return OK;
     }
 }

 status_t PrepareDir(const std::string& path, mode_t mode, uid_t uid, gid_t gid) {
     const char* cpath = path.c_str();

     char* secontext = nullptr;
     if (sehandle) {
         if (!selabel_lookup(sehandle, &secontext, cpath, S_IFDIR)) {
             setfscreatecon(secontext);
         }
     }

     int res = fs_prepare_dir(cpath, mode, uid, gid);

     if (secontext) {
         setfscreatecon(nullptr);
         freecon(secontext);
     }

     if (res == 0) {
         return OK;
     } else {
         return -errno;
     }
 }

 status_t ForceUnmount(const std::string& path) {
     const char* cpath = path.c_str();
     if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
         return OK;
     }
     PLOG(WARNING) << "Failed to unmount " << path;

     sleep(5);
     Process::killProcessesWithOpenFiles(cpath, SIGTERM);

     if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
         return OK;
     }
     PLOG(WARNING) << "Failed to unmount " << path;

     sleep(5);
     Process::killProcessesWithOpenFiles(cpath, SIGKILL);

     if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
         return OK;
     }
     PLOG(ERROR) << "Failed to unmount " << path;

     return -errno;
 }

 status_t BindMount(const std::string& source, const std::string& target) {
     if (::mount(source.c_str(), target.c_str(), "", MS_BIND, NULL)) {
         PLOG(ERROR) << "Failed to bind mount " << source << " to " << target;
         return -errno;
     }
     return OK;
 }

 static status_t readMetadata(const std::string& path, std::string& fsType,
         std::string& fsUuid, std::string& fsLabel, bool untrusted) {
     fsType.clear();
     fsUuid.clear();
     fsLabel.clear();

     std::string cmd(StringPrintf("%s -c /dev/null %s", kBlkidPath, path.c_str()));
     if (setexeccon(untrusted ? sBlkidUntrustedContext : sBlkidContext)) {
         LOG(ERROR) << "Failed to setexeccon()";
         return -EPERM;
     }
     FILE* fp = popen(cmd.c_str(), "r");
     if (setexeccon(NULL)) {
         abort();
     }
     if (!fp) {
         PLOG(ERROR) << "Failed to run " << cmd;
         return -errno;
     }

     status_t res = OK;
     char line[1024];
     char value[128];
     if (fgets(line, sizeof(line), fp) != nullptr) {
         LOG(DEBUG) << "blkid identified " << path << " as " << line;

         // Extract values from blkid output, if defined
         char* start = strstr(line, "TYPE=");
         if (start != nullptr && sscanf(start + 5, "\"%127[^\"]\"", value) == 1) {
             fsType = value;
         }

         start = strstr(line, "UUID=");
         if (start != nullptr && sscanf(start + 5, "\"%127[^\"]\"", value) == 1) {
             fsUuid = value;
         }

         start = strstr(line, "LABEL=");
         if (start != nullptr && sscanf(start + 6, "\"%127[^\"]\"", value) == 1) {
             fsLabel = value;
         }
     } else {
         LOG(WARNING) << "blkid failed to identify " << path;
         res = -ENODATA;
     }

     pclose(fp);
     return res;
 }

 status_t ReadMetadata(const std::string& path, std::string& fsType,
         std::string& fsUuid, std::string& fsLabel) {
     return readMetadata(path, fsType, fsUuid, fsLabel, false);
 }

 status_t ReadMetadataUntrusted(const std::string& path, std::string& fsType,
         std::string& fsUuid, std::string& fsLabel) {
     return readMetadata(path, fsType, fsUuid, fsLabel, true);
 }

 status_t ForkExecvp(const std::vector<std::string>& args, int* status,
         bool ignore_int_quit, bool logwrap) {
     int argc = args.size();
     char** argv = (char**) calloc(argc, sizeof(char*));
     for (int i = 0; i < argc; i++) {
         argv[i] = (char*) args[i].c_str();
         if (i == 0) {
             LOG(VERBOSE) << args[i];
         } else {
             LOG(VERBOSE) << "    " << args[i];
         }
     }
     int res = android_fork_execvp(argc, argv, status, ignore_int_quit, logwrap);
     free(argv);
     return res;
 }

 status_t ReadRandomBytes(size_t bytes, std::string& out) {
     out.clear();

     int fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOFOLLOW));
     if (fd == -1) {
         return -errno;
     }

     char buf[BUFSIZ];
     size_t n;
     while ((n = TEMP_FAILURE_RETRY(read(fd, &buf[0], std::min(sizeof(buf), bytes)))) > 0) {
         out.append(buf, n);
         bytes -= n;
     }
     TEMP_FAILURE_RETRY(close(fd));

     if (bytes == 0) {
         return OK;
     } else {
         return -EIO;
     }
 }

 status_t HexToStr(const std::string& hex, std::string& str) {
     str.clear();
     bool even = true;
     char cur = 0;
     for (size_t i = 0; i < hex.size(); i++) {
         int val = 0;
         switch (hex[i]) {
         case ' ': case '-': case ':': continue;
         case 'f': case 'F': val = 15; break;
         case 'e': case 'E': val = 14; break;
         case 'd': case 'D': val = 13; break;
         case 'c': case 'C': val = 12; break;
         case 'b': case 'B': val = 11; break;
         case 'a': case 'A': val = 10; break;
         case '9': val = 9; break;
         case '8': val = 8; break;
         case '7': val = 7; break;
         case '6': val = 6; break;
         case '5': val = 5; break;
         case '4': val = 4; break;
         case '3': val = 3; break;
         case '2': val = 2; break;
         case '1': val = 1; break;
         case '0': val = 0; break;
         default: return -EINVAL;
         }

         if (even) {
             cur = val << 4;
         } else {
             cur += val;
             str.push_back(cur);
             cur = 0;
         }
         even = !even;
     }
     return even ? OK : -EINVAL;
 }

 static const char* kLookup = "0123456789abcdef";

 status_t StrToHex(const std::string& str, std::string& hex) {
     hex.clear();
     for (size_t i = 0; i < str.size(); i++) {
         hex.push_back(kLookup[str[i] >> 4]);
         hex.push_back(kLookup[str[i] & 0x0F]);
     }
     return OK;
 }

 }  // namespace vold
 }  // namespace android
	/*
	* Copyright (C) 2015 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 "sehandle.h"
	#include "Utils.h"
	#include "Process.h"

	#include <base/logging.h>
	#include <base/stringprintf.h>
	#include <cutils/fs.h>
	#include <private/android_filesystem_config.h>
	#include <logwrap/logwrap.h>

	#include <fcntl.h>
	#include <linux/fs.h>
	#include <stdlib.h>
	#include <sys/mount.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <sys/wait.h>

	#ifndef UMOUNT_NOFOLLOW
	#define UMOUNT_NOFOLLOW 0x00000008 /* Don't follow symlink on umount */
	#endif

	using android::base::StringPrintf;

	namespace android {
	namespace vold {

	security_context_t sBlkidContext = nullptr;
	security_context_t sBlkidUntrustedContext = nullptr;
	security_context_t sFsckContext = nullptr;
	security_context_t sFsckUntrustedContext = nullptr;

	static const char* kBlkidPath = "/system/bin/blkid";

	status_t CreateDeviceNode(const std::string& path, dev_t dev) {
	const char* cpath = path.c_str();
	status_t res = 0;

	char* secontext = nullptr;
	if (sehandle) {
	if (!selabel_lookup(sehandle, &secontext, cpath, S_IFBLK)) {
	setfscreatecon(secontext);
	}
	}

	mode_t mode = 0660 \| S_IFBLK;
	if (mknod(cpath, mode, dev) < 0) {
	if (errno != EEXIST) {
	PLOG(ERROR) << "Failed to create device node for " << major(dev)
	<< ":" << minor(dev) << " at " << path;
	res = -errno;
	}
	}

	if (secontext) {
	setfscreatecon(nullptr);
	freecon(secontext);
	}

	return res;
	}

	status_t DestroyDeviceNode(const std::string& path) {
	const char* cpath = path.c_str();
	if (TEMP_FAILURE_RETRY(unlink(cpath))) {
	return -errno;
	} else {
	return OK;
	}
	}

	status_t PrepareDir(const std::string& path, mode_t mode, uid_t uid, gid_t gid) {
	const char* cpath = path.c_str();

	char* secontext = nullptr;
	if (sehandle) {
	if (!selabel_lookup(sehandle, &secontext, cpath, S_IFDIR)) {
	setfscreatecon(secontext);
	}
	}

	int res = fs_prepare_dir(cpath, mode, uid, gid);

	if (secontext) {
	setfscreatecon(nullptr);
	freecon(secontext);
	}

	if (res == 0) {
	return OK;
	} else {
	return -errno;
	}
	}

	status_t ForceUnmount(const std::string& path) {
	const char* cpath = path.c_str();
	if (!umount2(cpath, UMOUNT_NOFOLLOW) \|\| errno == EINVAL \|\| errno == ENOENT) {
	return OK;
	}
	PLOG(WARNING) << "Failed to unmount " << path;

	sleep(5);
	Process::killProcessesWithOpenFiles(cpath, SIGTERM);

	if (!umount2(cpath, UMOUNT_NOFOLLOW) \|\| errno == EINVAL \|\| errno == ENOENT) {
	return OK;
	}
	PLOG(WARNING) << "Failed to unmount " << path;

	sleep(5);
	Process::killProcessesWithOpenFiles(cpath, SIGKILL);

	if (!umount2(cpath, UMOUNT_NOFOLLOW) \|\| errno == EINVAL \|\| errno == ENOENT) {
	return OK;
	}
	PLOG(ERROR) << "Failed to unmount " << path;

	return -errno;
	}

	status_t BindMount(const std::string& source, const std::string& target) {
	if (::mount(source.c_str(), target.c_str(), "", MS_BIND, NULL)) {
	PLOG(ERROR) << "Failed to bind mount " << source << " to " << target;
	return -errno;
	}
	return OK;
	}

	static status_t readMetadata(const std::string& path, std::string& fsType,
	std::string& fsUuid, std::string& fsLabel, bool untrusted) {
	fsType.clear();
	fsUuid.clear();
	fsLabel.clear();

	std::string cmd(StringPrintf("%s -c /dev/null %s", kBlkidPath, path.c_str()));
	if (setexeccon(untrusted ? sBlkidUntrustedContext : sBlkidContext)) {
	LOG(ERROR) << "Failed to setexeccon()";
	return -EPERM;
	}
	FILE* fp = popen(cmd.c_str(), "r");
	if (setexeccon(NULL)) {
	abort();
	}
	if (!fp) {
	PLOG(ERROR) << "Failed to run " << cmd;
	return -errno;
	}

	status_t res = OK;
	char line[1024];
	char value[128];
	if (fgets(line, sizeof(line), fp) != nullptr) {
	LOG(DEBUG) << "blkid identified " << path << " as " << line;

	// Extract values from blkid output, if defined
	char* start = strstr(line, "TYPE=");
	if (start != nullptr && sscanf(start + 5, "\"%127[^\"]\"", value) == 1) {
	fsType = value;
	}

	start = strstr(line, "UUID=");
	if (start != nullptr && sscanf(start + 5, "\"%127[^\"]\"", value) == 1) {
	fsUuid = value;
	}

	start = strstr(line, "LABEL=");
	if (start != nullptr && sscanf(start + 6, "\"%127[^\"]\"", value) == 1) {
	fsLabel = value;
	}
	} else {
	LOG(WARNING) << "blkid failed to identify " << path;
	res = -ENODATA;
	}

	pclose(fp);
	return res;
	}

	status_t ReadMetadata(const std::string& path, std::string& fsType,
	std::string& fsUuid, std::string& fsLabel) {
	return readMetadata(path, fsType, fsUuid, fsLabel, false);
	}

	status_t ReadMetadataUntrusted(const std::string& path, std::string& fsType,
	std::string& fsUuid, std::string& fsLabel) {
	return readMetadata(path, fsType, fsUuid, fsLabel, true);
	}

	status_t ForkExecvp(const std::vector<std::string>& args, int* status,
	bool ignore_int_quit, bool logwrap) {
	int argc = args.size();
	char argv = (char) calloc(argc, sizeof(char*));
	for (int i = 0; i < argc; i++) {
	argv[i] = (char*) args[i].c_str();
	if (i == 0) {
	LOG(VERBOSE) << args[i];
	} else {
	LOG(VERBOSE) << " " << args[i];
	}
	}
	int res = android_fork_execvp(argc, argv, status, ignore_int_quit, logwrap);
	free(argv);
	return res;
	}

	status_t ReadRandomBytes(size_t bytes, std::string& out) {
	out.clear();

	int fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY \| O_CLOEXEC \| O_NOFOLLOW));
	if (fd == -1) {
	return -errno;
	}

	char buf[BUFSIZ];
	size_t n;
	while ((n = TEMP_FAILURE_RETRY(read(fd, &buf[0], std::min(sizeof(buf), bytes)))) > 0) {
	out.append(buf, n);
	bytes -= n;
	}
	TEMP_FAILURE_RETRY(close(fd));

	if (bytes == 0) {
	return OK;
	} else {
	return -EIO;
	}
	}

	status_t HexToStr(const std::string& hex, std::string& str) {
	str.clear();
	bool even = true;
	char cur = 0;
	for (size_t i = 0; i < hex.size(); i++) {
	int val = 0;
	switch (hex[i]) {
	case ' ': case '-': case ':': continue;
	case 'f': case 'F': val = 15; break;
	case 'e': case 'E': val = 14; break;
	case 'd': case 'D': val = 13; break;
	case 'c': case 'C': val = 12; break;
	case 'b': case 'B': val = 11; break;
	case 'a': case 'A': val = 10; break;
	case '9': val = 9; break;
	case '8': val = 8; break;
	case '7': val = 7; break;
	case '6': val = 6; break;
	case '5': val = 5; break;
	case '4': val = 4; break;
	case '3': val = 3; break;
	case '2': val = 2; break;
	case '1': val = 1; break;
	case '0': val = 0; break;
	default: return -EINVAL;
	}

	if (even) {
	cur = val << 4;
	} else {
	cur += val;
	str.push_back(cur);
	cur = 0;
	}
	even = !even;
	}
	return even ? OK : -EINVAL;
	}

	static const char* kLookup = "0123456789abcdef";

	status_t StrToHex(const std::string& str, std::string& hex) {
	hex.clear();
	for (size_t i = 0; i < str.size(); i++) {
	hex.push_back(kLookup[str[i] >> 4]);
	hex.push_back(kLookup[str[i] & 0x0F]);
	}
	return OK;
	}

	} // namespace vold
	} // namespace android