dumputils.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

 * uses fmtId() internally.
 */
bool
buildACLCommands(const char *name, const char *type,
				 const char *acls, const char *owner,
				 int remoteVersion,
				 PQExpBuffer sql)
{
	char	  **aclitems;
	int			naclitems;
	int			i;
	PQExpBuffer grantee,
				grantor,
				privs,
				privswgo;
	PQExpBuffer firstsql,
				secondsql;
	bool		found_owner_privs = false;

	if (strlen(acls) == 0)
		return true;			/* object has default permissions */

	if (!parsePGArray(acls, &aclitems, &naclitems))
	{
		if (aclitems)
			free(aclitems);
		return false;
	}

	grantee = createPQExpBuffer();
	grantor = createPQExpBuffer();
	privs = createPQExpBuffer();
	privswgo = createPQExpBuffer();

	/*
	 * At the end, these two will be pasted together to form the result. But
	 * the owner privileges need to go before the other ones to keep the
	 * dependencies valid.	In recent versions this is normally the case, but
	 * in old versions they come after the PUBLIC privileges and that results
	 * in problems if we need to run REVOKE on the owner privileges.
	 */
	firstsql = createPQExpBuffer();
	secondsql = createPQExpBuffer();

	/*
	 * Always start with REVOKE ALL FROM PUBLIC, so that we don't have to
	 * wire-in knowledge about the default public privileges for different
	 * kinds of objects.
	 */
	appendPQExpBuffer(firstsql, "REVOKE ALL ON %s %s FROM PUBLIC;\n",
					  type, name);

	/* Scan individual ACL items */
	for (i = 0; i < naclitems; i++)
	{
		if (!parseAclItem(aclitems[i], type, name, remoteVersion,
						  grantee, grantor, privs, privswgo))
			return false;

		if (grantor->len == 0 && owner)
			printfPQExpBuffer(grantor, "%s", owner);

		if (privs->len > 0 || privswgo->len > 0)
		{
			if (owner
				&& strcmp(grantee->data, owner) == 0
				&& strcmp(grantor->data, owner) == 0)
			{
				found_owner_privs = true;

				/*
				 * For the owner, the default privilege level is ALL WITH
				 * GRANT OPTION (only ALL prior to 7.4).
				 */
				if (supports_grant_options(remoteVersion)
					? strcmp(privswgo->data, "ALL") != 0
					: strcmp(privs->data, "ALL") != 0)
				{
					appendPQExpBuffer(firstsql, "REVOKE ALL ON %s %s FROM %s;\n",
									  type, name,
									  fmtId(grantee->data));
					if (privs->len > 0)
						appendPQExpBuffer(firstsql, "GRANT %s ON %s %s TO %s;\n",
										  privs->data, type, name,
										  fmtId(grantee->data));
					if (privswgo->len > 0)
						appendPQExpBuffer(firstsql, "GRANT %s ON %s %s TO %s WITH GRANT OPTION;\n",
										  privswgo->data, type, name,
										  fmtId(grantee->data));
				}
			}
			else
			{
				/*
				 * Otherwise can assume we are starting from no privs.
				 */
				if (grantor->len > 0
					&& (!owner || strcmp(owner, grantor->data) != 0))
					appendPQExpBuffer(secondsql, "SET SESSION AUTHORIZATION %s;\n",
									  fmtId(grantor->data));

				if (privs->len > 0)
				{
					appendPQExpBuffer(secondsql, "GRANT %s ON %s %s TO ",
									  privs->data, type, name);
					if (grantee->len == 0)
						appendPQExpBuffer(secondsql, "PUBLIC;\n");
					else if (strncmp(grantee->data, "group ",
									 strlen("group ")) == 0)
						appendPQExpBuffer(secondsql, "GROUP %s;\n",
									fmtId(grantee->data + strlen("group ")));
					else
						appendPQExpBuffer(secondsql, "%s;\n", fmtId(grantee->data));
				}
				if (privswgo->len > 0)
				{
					appendPQExpBuffer(secondsql, "GRANT %s ON %s %s TO ",
									  privswgo->data, type, name);
					if (grantee->len == 0)
						appendPQExpBuffer(secondsql, "PUBLIC");
					else if (strncmp(grantee->data, "group ",
									 strlen("group ")) == 0)
						appendPQExpBuffer(secondsql, "GROUP %s",
									fmtId(grantee->data + strlen("group ")));
					else
						appendPQExpBuffer(secondsql, "%s", fmtId(grantee->data));
					appendPQExpBuffer(secondsql, " WITH GRANT OPTION;\n");
				}

				if (grantor->len > 0
					&& (!owner || strcmp(owner, grantor->data) != 0))
					appendPQExpBuffer(secondsql, "RESET SESSION AUTHORIZATION;\n");
			}
		}
	}

	/*
	 * If we didn't find any owner privs, the owner must have revoked 'em all
	 */
	if (!found_owner_privs && owner)
	{
		appendPQExpBuffer(firstsql, "REVOKE ALL ON %s %s FROM %s;\n",
						  type, name, fmtId(owner));
	}

	destroyPQExpBuffer(grantee);
	destroyPQExpBuffer(grantor);
	destroyPQExpBuffer(privs);
	destroyPQExpBuffer(privswgo);

	appendPQExpBuffer(sql, "%s%s", firstsql->data, secondsql->data);
	destroyPQExpBuffer(firstsql);
	destroyPQExpBuffer(secondsql);

	free(aclitems);

	return true;
}

/*
 * This will parse an aclitem string, having the general form
 *		username=privilegecodes/grantor
 * or
 *		group groupname=privilegecodes/grantor
 * (the /grantor part will not be present if pre-7.4 database).
 *
 * The returned grantee string will be the dequoted username or groupname
 * (preceded with "group " in the latter case).  The returned grantor is
 * the dequoted grantor name or empty.	Privilege characters are decoded
 * and split between privileges with grant option (privswgo) and without
 * (privs).
 *
 * Note: for cross-version compatibility, it's important to use ALL when
 * appropriate.
 */
static bool
parseAclItem(const char *item, const char *type, const char *name,
			 int remoteVersion,
			 PQExpBuffer grantee, PQExpBuffer grantor,
			 PQExpBuffer privs, PQExpBuffer privswgo)
{
	char	   *buf;
	bool		all_with_go = true;
	bool		all_without_go = true;
	char	   *eqpos;
	char	   *slpos;
	char	   *pos;

	buf = strdup(item);

	/* user or group name is string up to = */
	eqpos = copyAclUserName(grantee, buf);
	if (*eqpos != '=')
		return false;

	/* grantor may be listed after / */
	slpos = strchr(eqpos + 1, '/');
	if (slpos)
	{
		*slpos++ = '\0';
		slpos = copyAclUserName(grantor, slpos);
		if (*slpos != '\0')
			return false;
	}
	else
		resetPQExpBuffer(grantor);

	/* privilege codes */
#define CONVERT_PRIV(code, keywd) \
	if ((pos = strchr(eqpos + 1, code))) \
	{ \
		if (*(pos + 1) == '*') \
		{ \
			AddAcl(privswgo, keywd); \
			all_without_go = false; \
		} \
		else \
		{ \
			AddAcl(privs, keywd); \
			all_with_go = false; \
		} \
	} \
	else \
		all_with_go = all_without_go = false

	resetPQExpBuffer(privs);
	resetPQExpBuffer(privswgo);

	if (strcmp(type, "TABLE") == 0)
	{
		CONVERT_PRIV('a', "INSERT");
		CONVERT_PRIV('r', "SELECT");
		CONVERT_PRIV('R', "RULE");

		if (remoteVersion >= 70200)
		{
			CONVERT_PRIV('w', "UPDATE");
			CONVERT_PRIV('d', "DELETE");
			CONVERT_PRIV('x', "REFERENCES");
			CONVERT_PRIV('t', "TRIGGER");
		}
		else
		{
			/* 7.0 and 7.1 have a simpler worldview */
			CONVERT_PRIV('w', "UPDATE,DELETE");
		}
	}
	else if (strcmp(type, "FUNCTION") == 0)
		CONVERT_PRIV('X', "EXECUTE");
	else if (strcmp(type, "LANGUAGE") == 0)
		CONVERT_PRIV('U', "USAGE");
	else if (strcmp(type, "SCHEMA") == 0)
	{
		CONVERT_PRIV('C', "CREATE");
		CONVERT_PRIV('U', "USAGE");
	}
	else if (strcmp(type, "DATABASE") == 0)
	{
		CONVERT_PRIV('C', "CREATE");
		CONVERT_PRIV('T', "TEMPORARY");
	}
	else if (strcmp(type, "TABLESPACE") == 0)
		CONVERT_PRIV('C', "CREATE");
	else
		abort();

#undef CONVERT_PRIV

	if (all_with_go)
	{
		resetPQExpBuffer(privs);
		printfPQExpBuffer(privswgo, "ALL");
	}
	else if (all_without_go)
	{
		resetPQExpBuffer(privswgo);
		printfPQExpBuffer(privs, "ALL");
	}

	free(buf);

	return true;
}

/*
 * Transfer a user or group name starting at *input into the output buffer,
 * dequoting if needed.  Returns a pointer to just past the input name.
 * The name is taken to end at an unquoted '=' or end of string.
 */
static char *
copyAclUserName(PQExpBuffer output, char *input)
{
	resetPQExpBuffer(output);

	while (*input && *input != '=')
	{
		/*
		 * If user name isn't quoted, then just add it to the output buffer
		 */
		if (*input != '"')
			appendPQExpBufferChar(output, *input++);
		else
		{
			/* Otherwise, it's a quoted username */
			input++;
			/* Loop until we come across an unescaped quote */
			while (!(*input == '"' && *(input + 1) != '"'))
			{
				if (*input == '\0')
					return input;		/* really a syntax error... */

				/*
				 * Quoting convention is to escape " as "".  Keep this code in
				 * sync with putid() in backend's acl.c.
				 */
				if (*input == '"' && *(input + 1) == '"')
					input++;
				appendPQExpBufferChar(output, *input++);
			}
			input++;
		}
	}
	return input;
}

/*
 * Append a privilege keyword to a keyword list, inserting comma if needed.
 */
static void
AddAcl(PQExpBuffer aclbuf, const char *keyword)
{
	if (aclbuf->len > 0)
		appendPQExpBufferChar(aclbuf, ',');
	appendPQExpBuffer(aclbuf, "%s", keyword);
}