/*
 * Copyright (C) 2012 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

// G++ automatically defines _GNU_SOURCE, which then means that <string.h>
// gives us the GNU variant.
#undef _GNU_SOURCE

#include <string.h>

#include <errno.h>
#include <limits.h>

#include <async_safe/log.h>

#include "private/ErrnoRestorer.h"

#include <string.h>

#include "bionic/pthread_internal.h"

static const char* __sys_error_strings[] = {
    [0] = "Success",
    [EPERM] = "Operation not permitted",
    [ENOENT] = "No such file or directory",
    [ESRCH] = "No such process",
    [EINTR] = "Interrupted system call",
    [EIO] = "I/O error",
    [ENXIO] = "No such device or address",
    [E2BIG] = "Argument list too long",
    [ENOEXEC] = "Exec format error",
    [EBADF] = "Bad file descriptor",
    [ECHILD] = "No child processes",
    [EAGAIN] = "Try again",
    [ENOMEM] = "Out of memory",
    [EACCES] = "Permission denied",
    [EFAULT] = "Bad address",
    [ENOTBLK] = "Block device required",
    [EBUSY] = "Device or resource busy",
    [EEXIST] = "File exists",
    [EXDEV] = "Cross-device link",
    [ENODEV] = "No such device",
    [ENOTDIR] = "Not a directory",
    [EISDIR] = "Is a directory",
    [EINVAL] = "Invalid argument",
    [ENFILE] = "File table overflow",
    [EMFILE] = "Too many open files",
    [ENOTTY] = "Inappropriate ioctl for device",
    [ETXTBSY] = "Text file busy",
    [EFBIG] = "File too large",
    [ENOSPC] = "No space left on device",
    [ESPIPE] = "Illegal seek",
    [EROFS] = "Read-only file system",
    [EMLINK] = "Too many links",
    [EPIPE] = "Broken pipe",
    [EDOM] = "Math argument out of domain of func",
    [ERANGE] = "Math result not representable",
    [EDEADLK] = "Resource deadlock would occur",
    [ENAMETOOLONG] = "File name too long",
    [ENOLCK] = "No record locks available",
    [ENOSYS] = "Function not implemented",
    [ENOTEMPTY] = "Directory not empty",
    [ELOOP] = "Too many symbolic links encountered",
    [ENOMSG] = "No message of desired type",
    [EIDRM] = "Identifier removed",
    [ECHRNG] = "Channel number out of range",
    [EL2NSYNC] = "Level 2 not synchronized",
    [EL3HLT] = "Level 3 halted",
    [EL3RST] = "Level 3 reset",
    [ELNRNG] = "Link number out of range",
    [EUNATCH] = "Protocol driver not attached",
    [ENOCSI] = "No CSI structure available",
    [EL2HLT] = "Level 2 halted",
    [EBADE] = "Invalid exchange",
    [EBADR] = "Invalid request descriptor",
    [EXFULL] = "Exchange full",
    [ENOANO] = "No anode",
    [EBADRQC] = "Invalid request code",
    [EBADSLT] = "Invalid slot",
    [EBFONT] = "Bad font file format",
    [ENOSTR] = "Device not a stream",
    [ENODATA] = "No data available",
    [ETIME] = "Timer expired",
    [ENOSR] = "Out of streams resources",
    [ENONET] = "Machine is not on the network",
    [ENOPKG] = "Package not installed",
    [EREMOTE] = "Object is remote",
    [ENOLINK] = "Link has been severed",
    [EADV] = "Advertise error",
    [ESRMNT] = "Srmount error",
    [ECOMM] = "Communication error on send",
    [EPROTO] = "Protocol error",
    [EMULTIHOP] = "Multihop attempted",
    [EDOTDOT] = "RFS specific error",
    [EBADMSG] = "Not a data message",
    [EOVERFLOW] = "Value too large for defined data type",
    [ENOTUNIQ] = "Name not unique on network",
    [EBADFD] = "File descriptor in bad state",
    [EREMCHG] = "Remote address changed",
    [ELIBACC] = "Can not access a needed shared library",
    [ELIBBAD] = "Accessing a corrupted shared library",
    [ELIBSCN] = ".lib section in a.out corrupted",
    [ELIBMAX] = "Attempting to link in too many shared libraries",
    [ELIBEXEC] = "Cannot exec a shared library directly",
    [EILSEQ] = "Illegal byte sequence",
    [ERESTART] = "Interrupted system call should be restarted",
    [ESTRPIPE] = "Streams pipe error",
    [EUSERS] = "Too many users",
    [ENOTSOCK] = "Socket operation on non-socket",
    [EDESTADDRREQ] = "Destination address required",
    [EMSGSIZE] = "Message too long",
    [EPROTOTYPE] = "Protocol wrong type for socket",
    [ENOPROTOOPT] = "Protocol not available",
    [EPROTONOSUPPORT] = "Protocol not supported",
    [ESOCKTNOSUPPORT] = "Socket type not supported",
    [EOPNOTSUPP] = "Operation not supported on transport endpoint",
    [EPFNOSUPPORT] = "Protocol family not supported",
    [EAFNOSUPPORT] = "Address family not supported by protocol",
    [EADDRINUSE] = "Address already in use",
    [EADDRNOTAVAIL] = "Cannot assign requested address",
    [ENETDOWN] = "Network is down",
    [ENETUNREACH] = "Network is unreachable",
    [ENETRESET] = "Network dropped connection because of reset",
    [ECONNABORTED] = "Software caused connection abort",
    [ECONNRESET] = "Connection reset by peer",
    [ENOBUFS] = "No buffer space available",
    [EISCONN] = "Transport endpoint is already connected",
    [ENOTCONN] = "Transport endpoint is not connected",
    [ESHUTDOWN] = "Cannot send after transport endpoint shutdown",
    [ETOOMANYREFS] = "Too many references: cannot splice",
    [ETIMEDOUT] = "Connection timed out",
    [ECONNREFUSED] = "Connection refused",
    [EHOSTDOWN] = "Host is down",
    [EHOSTUNREACH] = "No route to host",
    [EALREADY] = "Operation already in progress",
    [EINPROGRESS] = "Operation now in progress",
    [ESTALE] = "Stale NFS file handle",
    [EUCLEAN] = "Structure needs cleaning",
    [ENOTNAM] = "Not a XENIX named type file",
    [ENAVAIL] = "No XENIX semaphores available",
    [EISNAM] = "Is a named type file",
    [EREMOTEIO] = "Remote I/O error",
    [EDQUOT] = "Quota exceeded",
    [ENOMEDIUM] = "No medium found",
    [EMEDIUMTYPE] = "Wrong medium type",
    [ECANCELED] = "Operation Canceled",
    [ENOKEY] = "Required key not available",
    [EKEYEXPIRED] = "Key has expired",
    [EKEYREVOKED] = "Key has been revoked",
    [EKEYREJECTED] = "Key was rejected by service",
    [EOWNERDEAD] = "Owner died",
    [ENOTRECOVERABLE] = "State not recoverable",
    [ERFKILL] = "Operation not possible due to RF-kill",
    [EHWPOISON] = "Memory page has hardware error",
};

static inline const char* __strerror_lookup(int error_number) {
  if (error_number < 0 || error_number >= static_cast<int>(arraysize(__sys_error_strings))) {
    return nullptr;
  }
  return __sys_error_strings[error_number];
}

int strerror_r(int error_number, char* buf, size_t buf_len) {
  ErrnoRestorer errno_restorer;
  size_t length;

  const char* error_name = __strerror_lookup(error_number);
  if (error_name != nullptr) {
    length = strlcpy(buf, error_name, buf_len);
  } else {
    length = async_safe_format_buffer(buf, buf_len, "Unknown error %d", error_number);
  }
  if (length >= buf_len) {
    errno_restorer.override(ERANGE);
    return -1;
  }

  return 0;
}

extern "C" char* __gnu_strerror_r(int error_number, char* buf, size_t buf_len) {
  ErrnoRestorer errno_restorer; // The glibc strerror_r doesn't set errno if it truncates...
  strerror_r(error_number, buf, buf_len);
  return buf; // ...and just returns whatever fit.
}

char* strerror(int error_number) {
  // Just return the original constant in the easy cases.
  char* result = const_cast<char*>(__strerror_lookup(error_number));
  if (result != nullptr) {
    return result;
  }

  bionic_tls& tls = __get_bionic_tls();
  result = tls.strerror_buf;
  strerror_r(error_number, result, sizeof(tls.strerror_buf));
  return result;
}