init: clean up file / socket descriptor creation

clang-tidy hinted that some of this code wasn't right.  Looking
deeper, there is really not much related to file and socket
descriptors, except that they're published in similar ways to the
environment.  All of the abstraction into a 'Descriptor' class takes
us further away from specifying what we really mean.

This removes that abstraction, adds stricter checks and better errors
for parsing init scripts, reports sockets and files that are unable to
be acquired before exec, and updates the README.md for the passcred
option.

Test: build, logd (uses files and sockets) works
Change-Id: I59e611e95c85bdbefa779ef69b32b9dd4ee203e2

1 files changed, 67 insertions, 30 deletions

diff --git a/init/service_parser.cpp b/init/service_parser.cpp
index 88ce364c4..0fbbeb828 100644
--- a/init/service_parser.cpp
+++ b/init/service_parser.cpp
@@ -17,6 +17,8 @@
 #include "service_parser.h"
 
 #include <linux/input.h>
+#include <stdlib.h>
+#include <sys/socket.h>
 
 #include <algorithm>
 #include <sstream>
@@ -28,6 +30,7 @@
 #include <system/thread_defs.h>
 
 #include "rlimit_parser.h"
+#include "service_utils.h"
 #include "util.h"
 
 #if defined(__ANDROID__)
@@ -344,64 +347,98 @@ Result<void> ServiceParser::ParseTimeoutPeriod(std::vector<std::string>&& args)
     return {};
 }
 
-template <typename T>
-Result<void> ServiceParser::AddDescriptor(std::vector<std::string>&& args) {
-    int perm = args.size() > 3 ? std::strtoul(args[3].c_str(), 0, 8) : -1;
-    Result<uid_t> uid = 0;
-    Result<gid_t> gid = 0;
-    std::string context = args.size() > 6 ? args[6] : "";
+// name type perm [ uid gid context ]
+Result<void> ServiceParser::ParseSocket(std::vector<std::string>&& args) {
+    SocketDescriptor socket;
+    socket.name = std::move(args[1]);
+
+    auto types = Split(args[2], "+");
+    if (types[0] == "stream") {
+        socket.type = SOCK_STREAM;
+    } else if (types[0] == "dgram") {
+        socket.type = SOCK_DGRAM;
+    } else if (types[0] == "seqpacket") {
+        socket.type = SOCK_SEQPACKET;
+    } else {
+        return Error() << "socket type must be 'dgram', 'stream' or 'seqpacket', got '" << types[0]
+                       << "' instead.";
+    }
+
+    if (types.size() > 1) {
+        if (types.size() == 2 && types[1] == "passcred") {
+            socket.passcred = true;
+        } else {
+            return Error() << "Only 'passcred' may be used to modify the socket type";
+        }
+    }
+
+    errno = 0;
+    char* end = nullptr;
+    socket.perm = strtol(args[3].c_str(), &end, 8);
+    if (errno != 0) {
+        return ErrnoError() << "Unable to parse permissions '" << args[3] << "'";
+    }
+    if (end == args[3].c_str() || *end != '\0') {
+        errno = EINVAL;
+        return ErrnoError() << "Unable to parse permissions '" << args[3] << "'";
+    }
 
     if (args.size() > 4) {
-        uid = DecodeUid(args[4]);
+        auto uid = DecodeUid(args[4]);
         if (!uid) {
             return Error() << "Unable to find UID for '" << args[4] << "': " << uid.error();
         }
+        socket.uid = *uid;
     }
 
     if (args.size() > 5) {
-        gid = DecodeUid(args[5]);
+        auto gid = DecodeUid(args[5]);
         if (!gid) {
             return Error() << "Unable to find GID for '" << args[5] << "': " << gid.error();
         }
+        socket.gid = *gid;
     }
 
-    auto descriptor = std::make_unique<T>(args[1], args[2], *uid, *gid, perm, context);
+    socket.context = args.size() > 6 ? args[6] : "";
 
-    auto old = std::find_if(
-            service_->descriptors_.begin(), service_->descriptors_.end(),
-            [&descriptor](const auto& other) { return descriptor.get() == other.get(); });
+    auto old = std::find_if(service_->sockets_.begin(), service_->sockets_.end(),
+                            [&socket](const auto& other) { return socket.name == other.name; });
 
-    if (old != service_->descriptors_.end()) {
-        return Error() << "duplicate descriptor " << args[1] << " " << args[2];
+    if (old != service_->sockets_.end()) {
+        return Error() << "duplicate socket descriptor '" << socket.name << "'";
     }
 
-    service_->descriptors_.emplace_back(std::move(descriptor));
-    return {};
-}
+    service_->sockets_.emplace_back(std::move(socket));
 
-// name type perm [ uid gid context ]
-Result<void> ServiceParser::ParseSocket(std::vector<std::string>&& args) {
-    if (!StartsWith(args[2], "dgram") && !StartsWith(args[2], "stream") &&
-        !StartsWith(args[2], "seqpacket")) {
-        return Error() << "socket type must be 'dgram', 'stream' or 'seqpacket'";
-    }
-    return AddDescriptor<SocketInfo>(std::move(args));
+    return {};
 }
 
-// name type perm [ uid gid context ]
+// name type
 Result<void> ServiceParser::ParseFile(std::vector<std::string>&& args) {
     if (args[2] != "r" && args[2] != "w" && args[2] != "rw") {
         return Error() << "file type must be 'r', 'w' or 'rw'";
     }
-    std::string expanded;
-    if (!expand_props(args[1], &expanded)) {
+
+    FileDescriptor file;
+    file.type = args[2];
+
+    if (!expand_props(args[1], &file.name)) {
         return Error() << "Could not expand property in file path '" << args[1] << "'";
     }
-    args[1] = std::move(expanded);
-    if ((args[1][0] != '/') || (args[1].find("../") != std::string::npos)) {
+    if (file.name[0] != '/' || file.name.find("../") != std::string::npos) {
         return Error() << "file name must not be relative";
     }
-    return AddDescriptor<FileInfo>(std::move(args));
+
+    auto old = std::find_if(service_->files_.begin(), service_->files_.end(),
+                            [&file](const auto& other) { return other.name == file.name; });
+
+    if (old != service_->files_.end()) {
+        return Error() << "duplicate file descriptor '" << file.name << "'";
+    }
+
+    service_->files_.emplace_back(std::move(file));
+
+    return {};
 }
 
 Result<void> ServiceParser::ParseUser(std::vector<std::string>&& args) {