shared/qemupipe/qemu_pipe.cpp

/*
 * Copyright (C) 2020 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 <errno.h>
#include <log/log.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <qemu_pipe_bp.h>

namespace {
int open_verbose(const char* name, int flags) {
    const int fd = QEMU_PIPE_RETRY(open(name, flags));
    if (fd < 0) {
        ALOGE("%s:%d: Could not open '%s': %s",
              __func__, __LINE__, name, strerror(errno));
    }
    return fd;
}

}  // namespace

extern "C" {

int qemu_pipe_open_ns(const char* ns, const char* pipeName, int flags) {
    if (pipeName == NULL || pipeName[0] == '\0') {
        errno = EINVAL;
        return -1;
    }

    const int fd = open_verbose("/dev/goldfish_pipe", flags);
    if (fd < 0) {
        return fd;
    }

    char buf[256];
    int bufLen;
    if (ns) {
        bufLen = snprintf(buf, sizeof(buf), "pipe:%s:%s", ns, pipeName);
    } else {
        bufLen = snprintf(buf, sizeof(buf), "pipe:%s", pipeName);
    }

    if (qemu_pipe_write_fully(fd, buf, bufLen + 1)) {
        ALOGE("%s:%d: Could not connect to the '%s' service: %s",
              __func__, __LINE__, buf, strerror(errno));
        return -1;
    }

    return fd;
}

int qemu_pipe_open(const char* pipeName) {
    return qemu_pipe_open_ns(NULL, pipeName, O_RDWR | O_NONBLOCK);
}

void qemu_pipe_close(int pipe) {
    close(pipe);
}

int qemu_pipe_read_fully(int pipe, void* buffer, int size) {
    char* p = (char*)buffer;

    while (size > 0) {
      int n = QEMU_PIPE_RETRY(qemu_pipe_read(pipe, p, size));
      if (n < 0) return n;

      p += n;
      size -= n;
    }

    return 0;
}

int qemu_pipe_write_fully(int pipe, const void* buffer, int size) {
    const char* p = (const char*)buffer;

    while (size > 0) {
      int n = QEMU_PIPE_RETRY(qemu_pipe_write(pipe, p, size));
      if (n < 0) return n;

      p += n;
      size -= n;
    }

    return 0;
}

int qemu_pipe_read(int pipe, void* buffer, int size) {
    return read(pipe, buffer, size);
}

int qemu_pipe_write(int pipe, const void* buffer, int size) {
    return write(pipe, buffer, size);
}

int qemu_pipe_try_again(int ret) {
    return (ret < 0) && (errno == EINTR || errno == EAGAIN);
}

void qemu_pipe_print_error(int pipe) {
    ALOGE("pipe error: fd %d errno %d", pipe, errno);
}

}  // extern "C"