Function passwordFromFile

src/interfaces/libpq/fe-connect.c:7240–7373

Get a password from the password file. Return value is malloc'd. */

/* Get a password from the password file. Return value is malloc'd. */
static char *
passwordFromFile(const char *hostname, const char *port, const char *dbname,
				 const char *username, const char *pgpassfile)
{
	FILE	   *fp;
	struct stat stat_buf;
	PQExpBufferData buf;

	if (dbname == NULL || dbname[0] == '\0')
		return NULL;

	if (username == NULL || username[0] == '\0')
		return NULL;

	/* 'localhost' matches pghost of '' or the default socket directory */
	if (hostname == NULL || hostname[0] == '\0')
		hostname = DefaultHost;
	else if (is_unixsock_path(hostname))

		/*
		 * We should probably use canonicalize_path(), but then we have to
		 * bring path.c into libpq, and it doesn't seem worth it.
		 */
		if (strcmp(hostname, DEFAULT_PGSOCKET_DIR) == 0)
			hostname = DefaultHost;

	if (port == NULL || port[0] == '\0')
		port = DEF_PGPORT_STR;

	/* If password file cannot be opened, ignore it. */
	if (stat(pgpassfile, &stat_buf) != 0)
		return NULL;

#ifndef WIN32
	if (!S_ISREG(stat_buf.st_mode))
	{
		fprintf(stderr,
				libpq_gettext("WARNING: password file \"%s\" is not a plain file\n"),
				pgpassfile);
		return NULL;
	}

	/* If password file is insecure, alert the user and ignore it. */
	if (stat_buf.st_mode & (S_IRWXG | S_IRWXO))
	{
		fprintf(stderr,
				libpq_gettext("WARNING: password file \"%s\" has group or world access; permissions should be u=rw (0600) or less\n"),
				pgpassfile);
		return NULL;
	}
#else

	/*
	 * On Win32, the directory is protected, so we don't have to check the
	 * file.
	 */
#endif