compiler: support new access attributes

src/lxc/af_unix.h

@@ -7,22 +7,35 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 
+#include "compiler.h"
+
 /* does not enforce \0-termination */
 extern int lxc_abstract_unix_open(const char *path, int type, int flags);
 extern void lxc_abstract_unix_close(int fd);
 /* does not enforce \0-termination */
 extern int lxc_abstract_unix_connect(const char *path);
+
 extern int lxc_abstract_unix_send_fds(int fd, int *sendfds, int num_sendfds,
-				      void *data, size_t size);
-extern int lxc_abstract_unix_send_fds_iov(int fd, int *sendfds,
-					  int num_sendfds, struct iovec *iov,
-					  size_t iovlen);
+				      void *data, size_t size)
+__access_r(2, 3) __access_r(4, 5);
+
+extern int lxc_abstract_unix_send_fds_iov(int fd, int *sendfds, int num_sendfds,
+					  struct iovec *iov, size_t iovlen)
+__access_r(2, 3);
+
+extern int lxc_abstract_unix_recv_fds(int fd, int *recvfds, int num_recvfds,
+				      void *data, size_t size)
+__access_r(2, 3) __access_r(4, 5);
+
 extern int lxc_unix_send_fds(int fd, int *sendfds, int num_sendfds, void *data,
 			     size_t size);
-extern int lxc_abstract_unix_recv_fds(int fd, int *recvfds, int num_recvfds,
-				      void *data, size_t size);
-extern int lxc_abstract_unix_send_credential(int fd, void *data, size_t size);
-extern int lxc_abstract_unix_rcv_credential(int fd, void *data, size_t size);
+
+extern int lxc_abstract_unix_send_credential(int fd, void *data, size_t size)
+__access_r(2, 3);
+
+extern int lxc_abstract_unix_rcv_credential(int fd, void *data, size_t size)
+__access_w(2, 3);
+
 extern int lxc_unix_sockaddr(struct sockaddr_un *ret, const char *path);
 extern int lxc_unix_connect(struct sockaddr_un *addr);
 extern int lxc_unix_connect_type(struct sockaddr_un *addr, int type);

src/lxc/compiler.h

@@ -57,4 +57,22 @@
 
 #define __cgfsng_ops
 
+/* access attribute */
+#define __access_r(x, y)
+#define __access_w(x, y)
+#define __access_rw(x, y)
+
+#ifdef __has_attribute
+#if __has_attribute(access)
+#undef __access_r
+#define __access_r(x, y) __attribute__((access(read_only, x, y)))
+
+#undef __access_w
+#define __access_w(x, y) __attribute__((access(write_only, x, y)))
+
+#undef __access_rw
+#define __access_rw(x, y) __attribute__((access(read_write, x, y)))
+#endif
+#endif
+
 #endif /* __LXC_COMPILER_H */

src/lxc/conf.h

@@ -401,7 +401,8 @@ struct lxc_conf {
 };
 
 extern int write_id_mapping(enum idtype idtype, pid_t pid, const char *buf,
-			    size_t buf_size);
+			    size_t buf_size)
+__access_r(3, 4);
 
 #ifdef HAVE_TLS
 extern thread_local struct lxc_conf *current_config;

src/lxc/confile.h

@@ -9,6 +9,8 @@
 #include <lxc/attach_options.h>
 #include <lxc/lxccontainer.h>
 
+#include "compiler.h"
+
 struct lxc_conf;
 struct lxc_list;
 
@@ -46,21 +48,24 @@ struct new_config_item {
 extern struct lxc_config_t *lxc_get_config(const char *key);
 
 /* List all available config items. */
-extern int lxc_list_config_items(char *retv, int inlen);
+extern int lxc_list_config_items(char *retv, int inlen)
+__access_rw(1, 2);
 
 /* Given a configuration key namespace (e.g. lxc.apparmor) list all associated
  * subkeys for that namespace.
  * Must be implemented when adding a new configuration key.
  */
 extern int lxc_list_subkeys(struct lxc_conf *conf, const char *key, char *retv,
-			    int inlen);
+			    int inlen)
+__access_rw(3, 4);
 
 /* List all configuration items associated with a given network. For example
  * pass "lxc.net.[i]" to retrieve all configuration items associated with
  * the network associated with index [i].
  */
 extern int lxc_list_net(struct lxc_conf *c, const char *key, char *retv,
-			int inlen);
+			int inlen)
+__access_rw(3, 4);
 
 extern int lxc_config_read(const char *file, struct lxc_conf *conf,
 			   bool from_include);

src/lxc/confile_utils.h

@@ -5,6 +5,7 @@
 
 #include <stdbool.h>
 
+#include "compiler.h"
 #include "conf.h"
 #include "confile_utils.h"
 
@@ -49,12 +50,16 @@ extern char *lxc_ipvlan_flag_to_isolation(int mode);
 
 extern int set_config_string_item(char **conf_item, const char *value);
 extern int set_config_string_item_max(char **conf_item, const char *value,
-				      size_t max);
+				      size_t max)
+__access_r(2, 3);
+
 extern int set_config_path_item(char **conf_item, const char *value);
 extern int set_config_bool_item(bool *conf_item, const char *value,
                                 bool empty_conf_action);
 extern int config_ip_prefix(struct in_addr *addr);
-extern int network_ifname(char *valuep, const char *value, size_t size);
+extern int network_ifname(char *valuep, const char *value, size_t size)
+__access_r(2, 3);
+
 extern void rand_complete_hwaddr(char *hwaddr);
 extern bool lxc_config_net_is_hwaddr(const char *line);
 extern bool new_hwaddr(char *hwaddr);

src/lxc/file_utils.h

@@ -12,27 +12,52 @@
 #include <sys/vfs.h>
 #include <unistd.h>
 
+#include "compiler.h"
+
 /* read and write whole files */
 extern int lxc_write_to_file(const char *filename, const void *buf,
-			     size_t count, bool add_newline, mode_t mode);
-extern int lxc_readat(int dirfd, const char *filename, void *buf, size_t count);
+			     size_t count, bool add_newline, mode_t mode)
+__access_r(2, 3);
+
+extern int lxc_readat(int dirfd, const char *filename, void *buf, size_t count)
+__access_w(3, 4);
+
 extern int lxc_writeat(int dirfd, const char *filename, const void *buf,
-		       size_t count);
+		       size_t count)
+__access_r(3, 4);
+
 extern int lxc_write_openat(const char *dir, const char *filename,
-			    const void *buf, size_t count);
-extern int lxc_read_from_file(const char *filename, void *buf, size_t count);
+			    const void *buf, size_t count)
+__access_r(3, 4);
+
+extern int lxc_read_from_file(const char *filename, void *buf, size_t count)
+__access_w(2, 3);
 
 /* send and receive buffers completely */
-extern ssize_t lxc_write_nointr(int fd, const void *buf, size_t count);
+extern ssize_t lxc_write_nointr(int fd, const void *buf, size_t count)
+__access_r(2, 3);
+
 extern ssize_t lxc_pwrite_nointr(int fd, const void *buf, size_t count,
-				 off_t offset);
-extern ssize_t lxc_send_nointr(int sockfd, void *buf, size_t len, int flags);
-extern ssize_t lxc_read_nointr(int fd, void *buf, size_t count);
+				 off_t offset)
+__access_r(2, 3);
+
+extern ssize_t lxc_send_nointr(int sockfd, void *buf, size_t len, int flags)
+__access_r(2, 3);
+
+extern ssize_t lxc_read_nointr(int fd, void *buf, size_t count)
+__access_w(2, 3);
+
 extern ssize_t lxc_read_nointr_expect(int fd, void *buf, size_t count,
-				      const void *expected_buf);
+				      const void *expected_buf)
+__access_w(2, 3);
+
 extern ssize_t lxc_read_file_expect(const char *path, void *buf, size_t count,
-				      const void *expected_buf);
-extern ssize_t lxc_recv_nointr(int sockfd, void *buf, size_t len, int flags);
+				      const void *expected_buf)
+__access_w(2, 3);
+
+extern ssize_t lxc_recv_nointr(int sockfd, void *buf, size_t len, int flags)
+__access_w(2, 3);
+
 ssize_t lxc_recvmsg_nointr_iov(int sockfd, struct iovec *iov, size_t iovlen,
 			       int flags);