// SPDX-License-Identifier: AGPL-1.0-only
// Copyright (C) 2018 Ludvig Strigeus <info@tunsafe.com>. All Rights Reserved.
#include "stdafx.h"

#include <assert.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <string>

#if defined(OS_POSIX)
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#endif

#include <vector>
#include <algorithm>
#include "tunsafe_types.h"

static const char kBase64Alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

char *base64_encode(const uint8 *input, size_t length, char *output, size_t output_size, size_t *out_length) {
  char *result, *r;
  const uint8 *end;

  size_t size = (length + 2) / 3 * 4 + 1;

  if (output != NULL) {
    result = output;
    assert(output_size >= size);
    if (output_size < size) {
      *result = 0;
      return NULL;
    }
  } else {
    result = (char*)malloc(size);
    if (!result)
      return NULL;
  }
  r = result;
  end = input + length - 3;
  // Encode full blocks
  while (input <= end) {
    uint32 a = (input[0] << 16) + (input[1] << 8) + input[2];
    input += 3;

    r[0] = kBase64Alphabet[(a >> 18)/* & 0x3F*/];
    r[1] = kBase64Alphabet[(a >> 12) & 0x3F];
    r[2] = kBase64Alphabet[(a >> 6) & 0x3F];
    r[3] = kBase64Alphabet[(a) & 0x3F];
    r += 4;
  }
  if (input == end + 2) {
    uint32 a = input[0] << 4;
    r[0] = kBase64Alphabet[(a >> 6) /*& 0x3F*/];
    r[1] = kBase64Alphabet[(a) & 0x3F];
    r[2] = '=';
    r[3] = '=';
    r += 4;
  } else if (input == end + 1) {
    uint32 a = (input[0] << 10) + (input[1] << 2);
    r[0] = kBase64Alphabet[(a >> 12) /*& 0x3F*/];
    r[1] = kBase64Alphabet[(a >> 6) & 0x3F];
    r[2] = kBase64Alphabet[(a) & 0x3F];
    r[3] = '=';
    r += 4;
  }
  if (out_length)
    *out_length = r - result;
  *r = 0;
  return result;
}

#define WHITESPACE 64
#define EQUALS     65
#define INVALID    66

static const unsigned char d[] = {
  66,66,66,66,66,66,66,66,66,66,64,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
  66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,62,66,66,66,63,52,53,
  54,55,56,57,58,59,60,61,66,66,66,65,66,66,66, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
  10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,66,66,66,66,66,66,26,27,28,
  29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,66,66,
  66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
  66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
  66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
  66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
  66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
  66,66,66,66,66,66
};

bool base64_decode(uint8 *in, size_t inLen, uint8 *out, size_t *outLen) {
  uint8 *end = in + inLen;
  uint8 iter = 0;
  uint32_t buf = 0;
  size_t len = 0;

  while (in < end) {
    unsigned char c = d[*in++];

    switch (c) {
    case WHITESPACE: continue;   /* skip whitespace */
    case INVALID:    return false;   /* invalid input, return error */
    case EQUALS:                 /* pad character, end of data */
      in = end;
      continue;
    default:
      buf = buf << 6 | c;
      iter++;
      if (iter == 4) {
        if ((len += 3) > *outLen) return 0; /* buffer overflow */
        *(out++) = (buf >> 16) & 255;
        *(out++) = (buf >> 8) & 255;
        *(out++) = buf & 255;
        buf = 0; iter = 0;

      }
    }
  }
  if (iter == 3) {
    if ((len += 2) > *outLen) return 0; /* buffer overflow */
    *(out++) = (buf >> 10) & 255;
    *(out++) = (buf >> 2) & 255;
  } else if (iter == 2) {
    if (++len > *outLen) return 0; /* buffer overflow */
    *(out++) = (buf >> 4) & 255;
  }
  *outLen = len;
  return true;
}



int RunCommand(const char *fmt, ...) {
  const char *fmt_org = fmt;
  va_list va;
  std::string tmp;
  char buf[32], c;
  char *args[33];
  char *envp[1] = {NULL};
  int nargs = 0;
  bool didadd = false;
  va_start(va, fmt);
  for (;;) {
    c = *fmt++;
    if (c == '%') {
      c = *fmt++;
      if (c == 0) goto ZERO;
      if (c == 's') {
        char *arg = va_arg(va, char*);
        if (arg != NULL) {
          tmp += arg;
          didadd = true;
        }
      } else if (c == 'd') {
        snprintf(buf, 32, "%d", va_arg(va, int));
        tmp += buf;
      } else if (c == '%') {
        tmp += '%';
      } else if (c == 'A') {
        struct in_addr in;
        in.s_addr = htonl(va_arg(va, in_addr_t));
        tmp += inet_ntoa(in);
      }
    } else if (c == ' ' || c == 0) {
ZERO:
      if (!tmp.empty() || didadd) {
        args[nargs++] = _strdup(tmp.c_str());
        tmp.clear();
        if (nargs == 32 || c == 0) break;
      }
      didadd = false;
    } else {
      tmp += c;
    }
  }
  args[nargs] = 0;

  fprintf(stderr, "Run:");
  for (int i = 0; args[i]; i++)
    fprintf(stderr, " %s", args[i]);
  fprintf(stderr, "\n");

  int ret = -1;


#if defined(OS_POSIX)
  pid_t pid = fork();
  if (pid == 0) {
    execve(args[0], args, envp);
    exit(127);
  }
  if (pid < 0) {
    RERROR("Fork failed");
  } else if (waitpid(pid, &ret, 0) != pid) {
    ret = -1;
  }
#endif

  if (ret != 0)
    RERROR("Command failed %d!", ret);

  return ret;
}

bool IsOnlyZeros(const uint8 *data, size_t data_size) {
  for (size_t i = 0; i != data_size; i++)
    if (data[i])
      return false;
  return true;
}


#ifdef _MSC_VER
void printhex(const char *name, const void *a, size_t l) {
  char buf[256];
  snprintf(buf, 256, "%s (%d):", name, (int)l); OutputDebugString(buf);
  for (size_t i = 0; i < l; i++) {
    if (i % 4 == 0) printf(" ");
    snprintf(buf, 256, "%.2X", *((uint8*)a + i)); OutputDebugString(buf);
  }
  OutputDebugString("\n");
}

#else
void printhex(const char *name, const void *a, size_t l) {
  printf("%s (%d):", name, (int)l);
  for (size_t i = 0; i < l; i++) {
    if (i % 4 == 0) printf(" ");
    printf("%.2X", *((uint8*)a + i));
  }
  printf("\n");
}
#endif

typedef void Logger(const char *msg);
Logger *g_logger;

#undef RERROR
#undef void 

void RERROR(const char *msg, ...);

void RERROR(const char *msg, ...) {
  va_list va;
  char buf[512];
  va_start(va, msg);
  vsnprintf(buf, sizeof(buf), msg, va);
  va_end(va);
  if (g_logger) {
    g_logger(buf);
  } else {
    fputs(buf, stderr);
    fputs("\n", stderr);
  }
}


void RINFO(const char *msg, ...) {
  va_list va;
  char buf[512];
  va_start(va, msg);
  vsnprintf(buf, sizeof(buf), msg, va);
  va_end(va);
  if (g_logger) {
    g_logger(buf);
  } else {
    fputs(buf, stderr);
    fputs("\n", stderr);
  }
}

void *memdup(const void *p, size_t size) {
  void *x = malloc(size);
  if (x)
    memcpy(x, p, size);
  return x;
}

char *my_strndup(const char *p, size_t size) {
  char *x = (char*)malloc(size + 1);
  if (x) {
    x[size] = 0;
    memcpy(x, p, size);
  }
  return x;
}

size_t my_strlcpy(char *dst, size_t dstsize, const char *src) {
  size_t len = strlen(src);
  if (dstsize) {
    size_t lenx = std::min<size_t>(dstsize - 1, len);
    dst[lenx] = 0;
    memcpy(dst, src, lenx);
  }
  return len;
}

void OsGetRandomBytes(uint8 *data, size_t data_size) {
#if defined(OS_WIN)
  static BOOLEAN(APIENTRY *pfn)(void*, ULONG);
  if (!pfn) {
    pfn = (BOOLEAN(APIENTRY *)(void*, ULONG))GetProcAddress(LoadLibrary("ADVAPI32.DLL"), "SystemFunction036");
    if (!pfn)
      ExitProcess(1);
  }
  if (!pfn(data, (ULONG)data_size)) {
    ExitProcess(1);
    return;
  }
#elif defined(OS_POSIX)
  int fd = open("/dev/urandom", O_RDONLY);
  if (fd < 0) {
    fprintf(stderr, "/dev/urandom failed\n");
    exit(1);
  }
  int r = read(fd, data, data_size);
  if (r != data_size) {
    fprintf(stderr, "/dev/urandom failed\n");
    exit(1);
  }
  close(fd);
#else
#error
#endif
}

bool ParseConfigKeyValue(char *m, std::vector<std::pair<char *, char*>> *result) {
  for (;;) {
    char *nl = strchr(m, '\n');
    if (nl)
      *nl = 0;
    if (*m != '\0') {
      char *value = strchr(m, '=');
      if (value == NULL)
        return false;
      *value++ = '\0';
      result->emplace_back(m, value);
    }
    if (!nl)
      return true;
    m = nl + 1;
  }
}

bool ParseHexString(const char *text, void *data, size_t data_size) {
  size_t len = strlen(text);
  if (len != data_size * 2)
    return false;
  for (size_t i = 0; i < data_size; i++) {
    uint32 c = text[i * 2 + 0];
    if (c >= '0' && c <= '9') {
      c -= '0';
    } else if ((c |= 32) >= 'a' && c <= 'f') {
      c -= 'a' - 10;
    } else {
      return false;
    }
    uint32 d = text[i * 2 + 1];
    if (d >= '0' && d <= '9') {
      d -= '0';
    } else if ((d |= 32) >= 'a' && d <= 'f') {
      d -= 'a' - 10;
    } else {
      return false;
    }
    ((uint8*)data)[i] = c * 16 + d;
  }
  return true;
}

bool is_space(uint8_t c) {
  return c == ' ' || c == '\r' || c == '\n' || c == '\t';
}

void SplitString(char *s, int separator, std::vector<char*> *components) {
  components->clear();
  for (;;) {
    while (is_space(*s)) s++;
    char *d = strchr(s, separator);
    if (d == NULL) {
      if (*s)
        components->push_back(s);
      return;
    }
    *d = 0;
    char *e = d;
    while (e > s && is_space(e[-1]))
      *--e = 0;
    components->push_back(s);
    s = d + 1;
  }
}

void PrintHexString(const void *data, size_t data_size, char *result) {
  for (size_t i = 0; i < data_size; i++) {
    uint8 c = ((uint8*)data)[i];
    *result++ = "0123456789abcdef"[c >> 4];
    *result++ = "0123456789abcdef"[c & 0xF];
  }
  *result++ = 0;
}

bool ParseBase64Key(const char *s, uint8 key[32]) {
  size_t size = 32;
  return base64_decode((uint8*)s, strlen(s), key, &size) && size == 32;
}