Merge "libcutils: Simplify android_get_control_socket()" am: 5f70ed6e

#include "android_get_control_env.h"

#ifndef TEMP_FAILURE_RETRY

#define TEMP_FAILURE_RETRY(exp) (exp) // KISS implementation

#endif

#if defined(__ANDROID__)

/* For the socket trust (credentials) check */

#include <private/android_filesystem_config.h>

    // Compare to UNIX domain socket name, must match!

    struct sockaddr_un addr;

    socklen_t addrlen = sizeof(addr);

    int ret = TEMP_FAILURE_RETRY(getsockname(fd, (struct sockaddr *)&addr, &addrlen));

    int ret = getsockname(fd, (struct sockaddr*)&addr, &addrlen);

    if (ret < 0) return -1;

    char *path = NULL;

    if (asprintf(&path, ANDROID_SOCKET_DIR "/%s", name) < 0) return -1;

    if (!path) return -1;

    int cmp = strcmp(addr.sun_path, path);

    free(path);

    if (cmp != 0) return -1;

    constexpr char prefix[] = ANDROID_SOCKET_DIR "/";

    constexpr size_t prefix_size = sizeof(prefix) - sizeof('\0');

    if ((strncmp(addr.sun_path, prefix, prefix_size) == 0) &&

        (strcmp(addr.sun_path + prefix_size, name) == 0)) {

        // It is what we think it is

        return fd;

    }

    return -1;

}