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Merge "libc: __system_property_set uses writev to write atomically"

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Treehugger Robot 2017-02-25 02:06:19 +00:00 committed by Gerrit Code Review
commit 3246b9d8ae
3 changed files with 134 additions and 61 deletions
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180
libc/bionic/system_properties.cpp
View file

@ -34,7 +34,6 @@
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
@ -47,6 +46,7 @@
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <sys/xattr.h>
@ -487,8 +487,8 @@ const prop_info* prop_area::find_property(prop_bt* const trie, const char* name,
class PropertyServiceConnection {
public:
PropertyServiceConnection() : last_error_(0) {
fd_ = socket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (fd_ == -1) {
socket_ = ::socket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (socket_ == -1) {
last_error_ = errno;
return;
}
@ -500,54 +500,33 @@ class PropertyServiceConnection {
addr.sun_family = AF_LOCAL;
socklen_t alen = namelen + offsetof(sockaddr_un, sun_path) + 1;
if (TEMP_FAILURE_RETRY(connect(fd_, reinterpret_cast<sockaddr*>(&addr), alen)) == -1) {
close(fd_);
fd_ = -1;
if (TEMP_FAILURE_RETRY(connect(socket_, reinterpret_cast<sockaddr*>(&addr), alen)) == -1) {
close(socket_);
socket_ = -1;
last_error_ = errno;
}
}
bool IsValid() {
return fd_ != -1;
return socket_ != -1;
}
int GetLastError() {
return last_error_;
}
bool SendUint32(uint32_t value) {
int result = TEMP_FAILURE_RETRY(send(fd_, &value, sizeof(value), 0));
return CheckSendRecvResult(result, sizeof(value));
}
bool SendString(const char* value) {
uint32_t valuelen = strlen(value);
if (!SendUint32(valuelen)) {
return false;
}
// Trying to send even 0 bytes to closed socket may lead to
// broken pipe (http://b/34670529).
if (valuelen == 0) {
return true;
}
int result = TEMP_FAILURE_RETRY(send(fd_, value, valuelen, 0));
return CheckSendRecvResult(result, valuelen);
}
bool RecvInt32(int32_t* value) {
int result = TEMP_FAILURE_RETRY(recv(fd_, value, sizeof(*value), MSG_WAITALL));
int result = TEMP_FAILURE_RETRY(recv(socket_, value, sizeof(*value), MSG_WAITALL));
return CheckSendRecvResult(result, sizeof(*value));
}
int GetFd() {
return fd_;
int socket() {
return socket_;
}
~PropertyServiceConnection() {
if (fd_ != -1) {
close(fd_);
if (socket_ != -1) {
close(socket_);
}
}
@ -564,8 +543,69 @@ class PropertyServiceConnection {
return last_error_ == 0;
}
int fd_;
int socket_;
int last_error_;
friend class SocketWriter;
};
class SocketWriter {
public:
explicit SocketWriter(PropertyServiceConnection* connection)
: connection_(connection), iov_index_(0), uint_buf_index_(0)
{}
SocketWriter& WriteUint32(uint32_t value) {
CHECK(uint_buf_index_ < kUintBufSize);
CHECK(iov_index_ < kIovSize);
uint32_t* ptr = uint_buf_ + uint_buf_index_;
uint_buf_[uint_buf_index_++] = value;
iov_[iov_index_].iov_base = ptr;
iov_[iov_index_].iov_len = sizeof(*ptr);
++iov_index_;
return *this;
}
SocketWriter& WriteString(const char* value) {
uint32_t valuelen = strlen(value);
WriteUint32(valuelen);
if (valuelen == 0) {
return *this;
}
CHECK(iov_index_ < kIovSize);
iov_[iov_index_].iov_base = const_cast<char*>(value);
iov_[iov_index_].iov_len = valuelen;
++iov_index_;
return *this;
}
bool Send() {
if (!connection_->IsValid()) {
return false;
}
if (writev(connection_->socket(), iov_, iov_index_) == -1) {
connection_->last_error_ = errno;
return false;
}
iov_index_ = uint_buf_index_ = 0;
return true;
}
private:
static constexpr size_t kUintBufSize = 8;
static constexpr size_t kIovSize = 8;
PropertyServiceConnection* connection_;
iovec iov_[kIovSize];
size_t iov_index_;
uint32_t uint_buf_[kUintBufSize];
size_t uint_buf_index_;
DISALLOW_IMPLICIT_CONSTRUCTORS(SocketWriter);
};
struct prop_msg {
@ -581,9 +621,9 @@ static int send_prop_msg(const prop_msg* msg) {
}
int result = -1;
int fd = connection.GetFd();
int s = connection.socket();
const int num_bytes = TEMP_FAILURE_RETRY(send(fd, msg, sizeof(prop_msg), 0));
const int num_bytes = TEMP_FAILURE_RETRY(send(s, msg, sizeof(prop_msg), 0));
if (num_bytes == sizeof(prop_msg)) {
// We successfully wrote to the property server but now we
// wait for the property server to finish its work. It
@ -593,7 +633,7 @@ static int send_prop_msg(const prop_msg* msg) {
// once the socket closes. Out of paranoia we cap our poll
// at 250 ms.
pollfd pollfds[1];
pollfds[0].fd = fd;
pollfds[0].fd = s;
pollfds[0].events = 0;
const int poll_result = TEMP_FAILURE_RETRY(poll(pollfds, 1, 250 /* ms */));
if (poll_result == 1 && (pollfds[0].revents & POLLHUP) != 0) {
@ -1230,7 +1270,6 @@ int __system_property_set(const char* key, const char* value) {
detect_protocol_version();
}
int result = -1;
if (g_propservice_protocol_version == kProtocolVersion1) {
// Old protocol does not support long names
if (strlen(key) >= PROP_NAME_MAX) return -1;
@ -1241,27 +1280,60 @@ int __system_property_set(const char* key, const char* value) {
strlcpy(msg.name, key, sizeof msg.name);
strlcpy(msg.value, value, sizeof msg.value);
result = send_prop_msg(&msg);
return send_prop_msg(&msg);
} else {
// Use proper protocol
PropertyServiceConnection connection;
if (connection.IsValid() && connection.SendUint32(PROP_MSG_SETPROP2) &&
connection.SendString(key) && connection.SendString(value) &&
connection.RecvInt32(&result)) {
if (result != PROP_SUCCESS) {
__libc_format_log(ANDROID_LOG_WARN, "libc",
"Unable to set property \"%s\" to \"%s\": error code: 0x%x", key, value,
result);
}
} else {
result = connection.GetLastError();
__libc_format_log(ANDROID_LOG_WARN, "libc",
"Unable to set property \"%s\" to \"%s\": error code: 0x%x (%s)", key,
value, result, strerror(result));
if (!connection.IsValid()) {
errno = connection.GetLastError();
__libc_format_log(ANDROID_LOG_WARN,
"libc",
"Unable to set property \"%s\" to \"%s\": connection failed; errno=%d (%s)",
key,
value,
errno,
strerror(errno));
return -1;
}
}
return result != 0 ? -1 : 0;
SocketWriter writer(&connection);
if (!writer.WriteUint32(PROP_MSG_SETPROP2).WriteString(key).WriteString(value).Send()) {
errno = connection.GetLastError();
__libc_format_log(ANDROID_LOG_WARN,
"libc",
"Unable to set property \"%s\" to \"%s\": write failed; errno=%d (%s)",
key,
value,
errno,
strerror(errno));
return -1;
}
int result = -1;
if (!connection.RecvInt32(&result)) {
errno = connection.GetLastError();
__libc_format_log(ANDROID_LOG_WARN,
"libc",
"Unable to set property \"%s\" to \"%s\": recv failed; errno=%d (%s)",
key,
value,
errno,
strerror(errno));
return -1;
}
if (result != PROP_SUCCESS) {
__libc_format_log(ANDROID_LOG_WARN,
"libc",
"Unable to set property \"%s\" to \"%s\": error code: 0x%x",
key,
value,
result);
return -1;
}
return 0;
}
}
int __system_property_update(prop_info* pi, const char* value, unsigned int len) {

8
libc/private/libc_logging.h
View file

@ -97,6 +97,14 @@ int __libc_format_log_va_list(int pri, const char* _Nonnull tag, const char* _No
#endif
int __libc_write_log(int pri, const char* _Nonnull tag, const char* _Nonnull msg);
#define CHECK(predicate) \
do { \
if (!(predicate)) { \
__libc_fatal("%s:%d: %s CHECK '" #predicate "' failed", \
__FILE__, __LINE__, __FUNCTION__); \
} \
} while(0)
__END_DECLS
#endif

7
linker/linker_debug.h
View file

@ -59,13 +59,6 @@
__LIBC_HIDDEN__ extern int g_ld_debug_verbosity;
#define CHECK(predicate) { \
if (!(predicate)) { \
__libc_fatal("%s:%d: %s CHECK '" #predicate "' failed", \
__FILE__, __LINE__, __FUNCTION__); \
} \
}
#if LINKER_DEBUG_TO_LOG
#define _PRINTVF(v, x...) \
do { \