cosmopolitan/libc/fmt/strerror_r.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/safemacros.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/fmt/fmt.h"
#include "libc/macros.h"
#include "libc/nt/enum/formatmessageflags.h"
#include "libc/nt/process.h"
#include "libc/nt/runtime.h"
#include "libc/str/str.h"

const char *geterrname(int code) {
  extern const char kErrnoNames[];
  const long *e;
  size_t i, n;
  e = &E2BIG;
  n = &EXFULL + 1 - e;
  for (i = 0; i < n; ++i) {
    if (code == e[i]) {
      return IndexDoubleNulString(kErrnoNames, i);
    }
  }
  return NULL;
}

/**
 * Converts errno value to string.
 * @return 0 on success, or error code
 */
int strerror_r(int err, char *buf, size_t size) {
  const char *s;
  if (err == -1 || IsTiny()) {
    s = "?";
  } else {
    s = firstnonnull(geterrname(err), "?");
  }
  if (!SupportsWindows()) {
    DebugBreak();
    snprintf(buf, size, "E%s[%d]", s, err);
  } else {
    char16_t buf16[100];
    int winstate, sysvstate;
    winstate = GetLastError();
    sysvstate = errno;
    if (FormatMessage(
            kNtFormatMessageFromSystem | kNtFormatMessageIgnoreInserts, NULL,
            err, 0, buf16, ARRAYLEN(buf16) - 1, 0) > 0) {
      chomp16(buf16);
    } else {
      buf16[0] = u'\0';
    }
    snprintf(buf, size, "E%s/err=%d/errno:%d/GetLastError:%d%s%hs", s, err,
             sysvstate, winstate, buf16[0] ? " " : "", buf16);
  }
  return 0;
}