thodg/libgit2/tests/clar/sandbox.h

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• Hash : 212ae9a7
  Author :
  Date : 2020-12-21T06:48:48
  

  Fix the `-DENABLE_WERROR=ON` build for gcc 10.2
  
  This change makes it possible to build with newer versions of gcc
  without warnings. There were two warnings issued:
  
  * gcc 8 added
    [`-Wstringop-truncation`](https://developers.redhat.com/blog/2018/05/24/detecting-string-truncation-with-gcc-8/),
    which warns if a call to `strncpy(3)` is prone to accidentally
    truncating the destination string, since `strncpy(3)` does NOT add a
    terminating `NULL` if the destination buffer is not large enough to
    hold the input.
  
    This change uses the pattern suggested in
    https://us-cert.cisa.gov/bsi/articles/knowledge/coding-practices/strncpy-and-strncat
    to fix the locations flagged by gcc.
  * There was a potentially uninitialized access of `dest` in `fs_copy`.
  

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• tests/clar/sandbox.h

• #ifdef __APPLE__
  #include <sys/syslimits.h>
  #endif
  
  static char _clar_path[4096 + 1];
  
  static int
  is_valid_tmp_path(const char *path)
  {
  	STAT_T st;
  
  	if (stat(path, &st) != 0)
  		return 0;
  
  	if (!S_ISDIR(st.st_mode))
  		return 0;
  
  	return (access(path, W_OK) == 0);
  }
  
  static int
  find_tmp_path(char *buffer, size_t length)
  {
  #ifndef _WIN32
  	static const size_t var_count = 5;
  	static const char *env_vars[] = {
  		"CLAR_TMP", "TMPDIR", "TMP", "TEMP", "USERPROFILE"
   	};
  
   	size_t i;
  
  	for (i = 0; i < var_count; ++i) {
  		const char *env = getenv(env_vars[i]);
  		if (!env)
  			continue;
  
  		if (is_valid_tmp_path(env)) {
  #ifdef __APPLE__
  			if (length >= PATH_MAX && realpath(env, buffer) != NULL)
  				return 0;
  #endif
  			strncpy(buffer, env, length - 1);
  			buffer[length - 1] = '\0';
  			return 0;
  		}
  	}
  
  	/* If the environment doesn't say anything, try to use /tmp */
  	if (is_valid_tmp_path("/tmp")) {
  #ifdef __APPLE__
  		if (length >= PATH_MAX && realpath("/tmp", buffer) != NULL)
  			return 0;
  #endif
  		strncpy(buffer, "/tmp", length - 1);
  		buffer[length - 1] = '\0';
  		return 0;
  	}
  
  #else
  	DWORD env_len = GetEnvironmentVariable("CLAR_TMP", buffer, (DWORD)length);
  	if (env_len > 0 && env_len < (DWORD)length)
  		return 0;
  
  	if (GetTempPath((DWORD)length, buffer))
  		return 0;
  #endif
  
  	/* This system doesn't like us, try to use the current directory */
  	if (is_valid_tmp_path(".")) {
  		strncpy(buffer, ".", length - 1);
  		buffer[length - 1] = '\0';
  		return 0;
  	}
  
  	return -1;
  }
  
  static void clar_unsandbox(void)
  {
  	if (_clar_path[0] == '\0')
  		return;
  
  	cl_must_pass(chdir(".."));
  
  	fs_rm(_clar_path);
  }
  
  static int build_sandbox_path(void)
  {
  #ifdef CLAR_TMPDIR
  	const char path_tail[] = CLAR_TMPDIR "_XXXXXX";
  #else
  	const char path_tail[] = "clar_tmp_XXXXXX";
  #endif
  
  	size_t len;
  
  	if (find_tmp_path(_clar_path, sizeof(_clar_path)) < 0)
  		return -1;
  
  	len = strlen(_clar_path);
  
  #ifdef _WIN32
  	{ /* normalize path to POSIX forward slashes */
  		size_t i;
  		for (i = 0; i < len; ++i) {
  			if (_clar_path[i] == '\\')
  				_clar_path[i] = '/';
  		}
  	}
  #endif
  
  	if (_clar_path[len - 1] != '/') {
  		_clar_path[len++] = '/';
  	}
  
  	strncpy(_clar_path + len, path_tail, sizeof(_clar_path) - len);
  
  #if defined(__MINGW32__)
  	if (_mktemp(_clar_path) == NULL)
  		return -1;
  
  	if (mkdir(_clar_path, 0700) != 0)
  		return -1;
  #elif defined(_WIN32)
  	if (_mktemp_s(_clar_path, sizeof(_clar_path)) != 0)
  		return -1;
  
  	if (mkdir(_clar_path, 0700) != 0)
  		return -1;
  #else
  	if (mkdtemp(_clar_path) == NULL)
  		return -1;
  #endif
  
  	return 0;
  }
  
  static int clar_sandbox(void)
  {
  	if (_clar_path[0] == '\0' && build_sandbox_path() < 0)
  		return -1;
  
  	if (chdir(_clar_path) != 0)
  		return -1;
  
  	return 0;
  }
  
  const char *clar_sandbox_path(void)
  {
  	return _clar_path;
  }
  
  

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