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1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "descriptors.h"
18 
19 #include <ctype.h>
20 #include <fcntl.h>
21 #include <sys/stat.h>
22 #include <unistd.h>
23 
24 #include <android-base/logging.h>
25 #include <android-base/stringprintf.h>
26 #include <android-base/strings.h>
27 #include <android-base/unique_fd.h>
28 #include <cutils/android_get_control_file.h>
29 #include <cutils/sockets.h>
30 
31 #include "util.h"
32 
33 namespace android {
34 namespace init {
35 
DescriptorInfo(const std::string & name,const std::string & type,uid_t uid,gid_t gid,int perm,const std::string & context)36 DescriptorInfo::DescriptorInfo(const std::string& name, const std::string& type, uid_t uid,
37                                gid_t gid, int perm, const std::string& context)
38         : name_(name), type_(type), uid_(uid), gid_(gid), perm_(perm), context_(context) {
39 }
40 
~DescriptorInfo()41 DescriptorInfo::~DescriptorInfo() {
42 }
43 
operator <<(std::ostream & os,const DescriptorInfo & info)44 std::ostream& operator<<(std::ostream& os, const DescriptorInfo& info) {
45   return os << "  descriptors " << info.name_ << " " << info.type_ << " " << std::oct << info.perm_;
46 }
47 
operator ==(const DescriptorInfo & other) const48 bool DescriptorInfo::operator==(const DescriptorInfo& other) const {
49   return name_ == other.name_ && type_ == other.type_ && key() == other.key();
50 }
51 
CreateAndPublish(const std::string & globalContext) const52 void DescriptorInfo::CreateAndPublish(const std::string& globalContext) const {
53   // Create
54   const std::string& contextStr = context_.empty() ? globalContext : context_;
55   int fd = Create(contextStr);
56   if (fd < 0) return;
57 
58   // Publish
59   std::string publishedName = key() + name_;
60   std::for_each(publishedName.begin(), publishedName.end(),
61                 [] (char& c) { c = isalnum(c) ? c : '_'; });
62 
63   std::string val = std::to_string(fd);
64   setenv(publishedName.c_str(), val.c_str(), 1);
65 
66   // make sure we don't close on exec
67   fcntl(fd, F_SETFD, 0);
68 }
69 
Clean() const70 void DescriptorInfo::Clean() const {
71 }
72 
SocketInfo(const std::string & name,const std::string & type,uid_t uid,gid_t gid,int perm,const std::string & context)73 SocketInfo::SocketInfo(const std::string& name, const std::string& type, uid_t uid,
74                        gid_t gid, int perm, const std::string& context)
75         : DescriptorInfo(name, type, uid, gid, perm, context) {
76 }
77 
Clean() const78 void SocketInfo::Clean() const {
79     std::string path = android::base::StringPrintf("%s/%s", ANDROID_SOCKET_DIR, name().c_str());
80     unlink(path.c_str());
81 }
82 
Create(const std::string & context) const83 int SocketInfo::Create(const std::string& context) const {
84     auto types = android::base::Split(type(), "+");
85     int flags =
86         ((types[0] == "stream" ? SOCK_STREAM : (types[0] == "dgram" ? SOCK_DGRAM : SOCK_SEQPACKET)));
87     bool passcred = types.size() > 1 && types[1] == "passcred";
88     return CreateSocket(name().c_str(), flags, passcred, perm(), uid(), gid(), context.c_str());
89 }
90 
key() const91 const std::string SocketInfo::key() const {
92   return ANDROID_SOCKET_ENV_PREFIX;
93 }
94 
FileInfo(const std::string & name,const std::string & type,uid_t uid,gid_t gid,int perm,const std::string & context)95 FileInfo::FileInfo(const std::string& name, const std::string& type, uid_t uid,
96                    gid_t gid, int perm, const std::string& context)
97         // defaults OK for uid,..., they are ignored for this class.
98         : DescriptorInfo(name, type, uid, gid, perm, context) {
99 }
100 
Create(const std::string &) const101 int FileInfo::Create(const std::string&) const {
102   int flags = (type() == "r") ? O_RDONLY :
103               (type() == "w") ? O_WRONLY :
104                                 O_RDWR;
105 
106   // Make sure we do not block on open (eg: devices can chose to block on
107   // carrier detect).  Our intention is never to delay launch of a service
108   // for such a condition.  The service can perform its own blocking on
109   // carrier detect.
110   android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(name().c_str(),
111                                                       flags | O_NONBLOCK)));
112 
113   if (fd < 0) {
114     PLOG(ERROR) << "Failed to open file '" << name().c_str() << "'";
115     return -1;
116   }
117 
118   // Fixup as we set O_NONBLOCK for open, the intent for fd is to block reads.
119   fcntl(fd, F_SETFL, flags);
120 
121   LOG(INFO) << "Opened file '" << name().c_str() << "'"
122             << ", flags " << std::oct << flags << std::dec;
123 
124   return fd.release();
125 }
126 
key() const127 const std::string FileInfo::key() const {
128   return ANDROID_FILE_ENV_PREFIX;
129 }
130 
131 }  // namespace init
132 }  // namespace android
133