/* 

   Unix SMB/CIFS implementation.

   Samba utility functions

   Copyright (C) Andrew Tridgell 1992-1998

   Copyright (C) Jeremy Allison 2001-2007

   Copyright (C) Simo Sorce 2001

   Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2003

   Copyright (C) James Peach 2006

   Copyright (c) 2020      Andreas Schneider <asn@samba.org>

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "replace.h"

#include "dynconfig/dynconfig.h"

#include "lib/util/util_paths.h"

#include "system/passwd.h"

#include "system/filesys.h"

/**

 * @brief Returns an absolute path to a file in the Samba modules directory.

 *

 * @param name File to find, relative to MODULESDIR.

 *

 * @retval Pointer to a string containing the full path.

 **/

char *modules_path(TALLOC_CTX *mem_ctx, const char *name)

{

  return talloc_asprintf(mem_ctx, "%s/%s", get_dyn_MODULESDIR(), name);

}

/**

 * @brief Returns an absolute path to a file in the Samba data directory.

 *

 * @param name File to find, relative to CODEPAGEDIR.

 *

 * @retval Pointer to a talloc'ed string containing the full path.

 **/

char *data_path(TALLOC_CTX *mem_ctx, const char *name)

{

  return talloc_asprintf(mem_ctx, "%s/%s", get_dyn_CODEPAGEDIR(), name);

}

/**

 * @brief Returns the platform specific shared library extension.

 *

 * @retval Pointer to a const char * containing the extension.

 **/

const char *shlib_ext(void)

{

  return get_dyn_SHLIBEXT();

}

static char *get_user_home_dir(TALLOC_CTX *mem_ctx)

{

  struct passwd pwd = {0};

  struct passwd *pwdbuf = NULL;

  char *buf = NULL;

  char *out = NULL;

  long int initlen;

  size_t len;

  int rc;

  initlen = sysconf(_SC_GETPW_R_SIZE_MAX);

  if (initlen == -1) {

    len = 1024;

  } else {

    len = (size_t)initlen;

  }

  buf = talloc_size(mem_ctx, len);

  if (buf == NULL) {

    return NULL;

  }

  rc = getpwuid_r(getuid(), &pwd, buf, len, &pwdbuf);

  while (rc == ERANGE) {

    size_t newlen = 2 * len;

    char *tmp = NULL;

    if (newlen < len) {

      /* Overflow */

      goto done;

    }

    len = newlen;

    tmp = talloc_realloc(mem_ctx, buf, char, len);

    if (tmp == NULL) {

      goto done;

    }

    buf = tmp;

    rc = getpwuid_r(getuid(), &pwd, buf, len, &pwdbuf);

  }

  if (rc != 0 || pwdbuf == NULL ) {

    const char *szPath = getenv("HOME");

    if (szPath == NULL) {

      goto done;

    }

    len = strnlen(szPath, PATH_MAX);

    if (len >= PATH_MAX) {

      goto done;

    }

    out = talloc_strdup(mem_ctx, szPath);

    goto done;

  }

  out = talloc_strdup(mem_ctx, pwd.pw_dir);

done:

  TALLOC_FREE(buf);

  return out;

}

char *path_expand_tilde(TALLOC_CTX *mem_ctx, const char *d)

{

  char *h = NULL, *r = NULL;

  const char *p = NULL;

  struct stat sb = {0};

  int rc;

  if (d[0] != '~') {

    return talloc_strdup(mem_ctx, d);

  }

  d++;

  /* handle ~user/path */

  p = strchr(d, '/');

  if (p != NULL && p > d) {

    struct passwd *pw;

    size_t s = p - d;

    char u[128];

    if (s >= sizeof(u)) {

      return NULL;

    }

    memcpy(u, d, s);

    u[s] = '\0';

    pw = getpwnam(u);

    if (pw == NULL) {

      return NULL;

    }

    h = talloc_strdup(mem_ctx, pw->pw_dir);

  } else {

    p = d;

    h = get_user_home_dir(mem_ctx);

  }

  if (h == NULL) {

    return NULL;

  }

  rc = stat(h, &sb);

  if (rc != 0) {

    TALLOC_FREE(h);

    return NULL;

  }

  r = talloc_asprintf(mem_ctx, "%s%s", h, p);

  TALLOC_FREE(h);

  return r;

}