Re: [PATCH v3 02/10] multipath-tools: add helper mpath_fill_sockaddr__()

[Benjamin Marzinski <bmarzins@redhat.com>]

On Fri, Feb 14, 2025 at 11:10:03PM +0100, Martin Wilck wrote:
> Create a static new helper function which is used by both libmpathcmd
> and libmpathutil and fills in the socket address name from the compile-time
> default. The function is able to handle both abstract and pathname sockets,
> but more changes are needed to make the latter actually work.
> 
> Signed-off-by: Martin Wilck <mwilck@suse.com>
> ---
>  .gitignore                                    |  1 +
>  Makefile.inc                                  |  7 ++--
>  create-config.mk                              |  1 +
>  libmpathcmd/mpath_cmd.c                       | 11 ++-----
>  libmpathcmd/mpath_fill_sockaddr.c             | 32 +++++++++++++++++++
>  libmpathutil/uxsock.c                         | 15 ++++-----
>  multipathd/Makefile                           |  4 +--
>  ...multipathd.socket => multipathd.socket.in} |  2 +-
>  8 files changed, 51 insertions(+), 22 deletions(-)
>  create mode 100644 libmpathcmd/mpath_fill_sockaddr.c
>  rename multipathd/{multipathd.socket => multipathd.socket.in} (87%)
> 
> diff --git a/.gitignore b/.gitignore
> index 4548cfb..6a1f6fc 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -24,6 +24,7 @@ multipathd/multipathd
>  multipathd/multipathd.8
>  multipathd/multipathc
>  multipathd/multipathd.service
> +multipathd/multipathd.socket
>  mpathpersist/mpathpersist
>  mpathpersist/mpathpersist.8
>  abi.tar.gz
> diff --git a/Makefile.inc b/Makefile.inc
> index 76efeb9..4015006 100644
> --- a/Makefile.inc
> +++ b/Makefile.inc
> @@ -79,7 +79,7 @@ libudev_incdir	:= $(or $(shell $(PKG_CONFIG) --variable=includedir libudev),/usr
>  kernel_incdir	:= /usr/include
>  sysdir_bin      := $(sys_execprefix)bin
>  
> -abstract_socket := /org/kernel/linux/storage/multipathd
> +abstract_socket := @/org/kernel/linux/storage/multipathd
>  
>  ifeq ($(V),)
>  Q		:= @
> @@ -117,7 +117,9 @@ CPPFLAGS	:= $(FORTIFY_OPT) $(CPPFLAGS) $(D_URCU_VERSION) \
>  		   -DRUNTIME_DIR=\"$(runtimedir)\" -DCONFIG_DIR=\"$(TGTDIR)$(configdir)\" \
>  		   -DDEFAULT_CONFIGFILE=\"$(TGTDIR)$(configfile)\" -DSTATE_DIR=\"$(TGTDIR)$(statedir)\" \
>  		   -DEXTRAVERSION=\"$(EXTRAVERSION)\" \
> -		   -DDEFAULT_SOCKET=\"$(abstract_socket)\" -MMD -MP
> +		   -DDEFAULT_SOCKET=\"$(abstract_socket)\" \
> +		   -DWSTRINGOP_TRUNCATION=$(if $(WSTRINGOP_TRUNCATION),1,0) \
> +		   -MMD -MP
>  CFLAGS		:= -std=$(C_STD) $(CFLAGS) $(OPTFLAGS) $(WARNFLAGS) -pipe \
>  		   -fexceptions
>  BIN_CFLAGS	:= -fPIE -DPIE
> @@ -170,4 +172,5 @@ NV_VERSION_SCRIPT = $(DEVLIB:%.so=%-nv.version)
>  		-e 's:@SYSDIR_BIN@:'$(sysdir_bin)': g' \
>  		-e 's:@RUNTIME_DIR@:'$(runtimedir)':g' \
>  		-e 's/@MODPROBE_UNIT@/'$(MODPROBE_UNIT)'/g' \
> +		-e 's,@MPATH_SOCKET@,'$(abstract_socket)',g' \
>  		$< >$@
> diff --git a/create-config.mk b/create-config.mk
> index ab163ed..f05fdab 100644
> --- a/create-config.mk
> +++ b/create-config.mk
> @@ -191,6 +191,7 @@ $(TOPDIR)/config.mk:	$(multipathdir)/autoconfig.h
>  	@echo "ERROR_DISCARDED_QUALIFIERS := $(call TEST_CC_OPTION,-Werror=discarded-qualifiers,)" >>$@
>  	@echo "WNOCLOBBERED := $(call TEST_CC_OPTION,-Wno-clobbered -Wno-error=clobbered,)" >>$@
>  	@echo "WFORMATOVERFLOW := $(call TEST_CC_OPTION,-Wformat-overflow=2,)" >>$@
> +	@echo "WSTRINGOP_TRUNCATION := $(call TEST_CC_OPTION,-Wstringop-truncation)" >>$@
>  	@echo "W_MISSING_INITIALIZERS := $(call TEST_MISSING_INITIALIZERS)" >>$@
>  	@echo "W_URCU_TYPE_LIMITS := $(call TEST_URCU_TYPE_LIMITS)" >>$@
>  	@echo "ENABLE_LIBDMMP := $(ENABLE_LIBDMMP)" >>$@
> diff --git a/libmpathcmd/mpath_cmd.c b/libmpathcmd/mpath_cmd.c
> index a38e8b6..5a39471 100644
> --- a/libmpathcmd/mpath_cmd.c
> +++ b/libmpathcmd/mpath_cmd.c
> @@ -24,11 +24,13 @@
>  #include <sys/socket.h>
>  #include <sys/un.h>
>  #include <poll.h>
> +#include <stddef.h>
>  #include <string.h>
>  #include <errno.h>
>  #include <fcntl.h>
>  
>  #include "mpath_cmd.h"
> +#include "mpath_fill_sockaddr.c"
>  
>  /*
>   * keep reading until its all read
> @@ -101,14 +103,6 @@ int mpath_connect__(int nonblocking)
>  	struct sockaddr_un addr;
>  	int flags = 0;
>  
> -	memset(&addr, 0, sizeof(addr));
> -	addr.sun_family = AF_LOCAL;
> -	addr.sun_path[0] = '\0';
> -	strncpy(&addr.sun_path[1], DEFAULT_SOCKET, sizeof(addr.sun_path) - 1);
> -	len = strlen(DEFAULT_SOCKET) + 1 + sizeof(sa_family_t);
> -	if (len > sizeof(struct sockaddr_un))
> -		len = sizeof(struct sockaddr_un);
> -
>  	fd = socket(AF_LOCAL, SOCK_STREAM, 0);
>  	if (fd == -1)
>  		return -1;
> @@ -119,6 +113,7 @@ int mpath_connect__(int nonblocking)
>  			(void)fcntl(fd, F_SETFL, flags|O_NONBLOCK);
>  	}
>  
> +	len = mpath_fill_sockaddr__(&addr, DEFAULT_SOCKET);
>  	if (connect(fd, (struct sockaddr *)&addr, len) == -1) {
>  		int err = errno;
>  
> diff --git a/libmpathcmd/mpath_fill_sockaddr.c b/libmpathcmd/mpath_fill_sockaddr.c
> new file mode 100644
> index 0000000..750ef3e
> --- /dev/null
> +++ b/libmpathcmd/mpath_fill_sockaddr.c
> @@ -0,0 +1,32 @@
> +/*
> + * Copyright (c) 2025 SUSE LLC
> + * SPDX-license-identifier: LGPL-2.1-or-newer
> + */
> +
> +static size_t mpath_fill_sockaddr__(struct sockaddr_un *addr, const char *name)
> +{
> +	size_t len;
> +
> +	addr->sun_family = AF_LOCAL;
> +
> +	if (name[0] != '@') {
> +		/* Pathname socket. This should be NULL-terminated. */
> +		strncpy(&addr->sun_path[0], name, sizeof(addr->sun_path) - 1);
> +		addr->sun_path[sizeof(addr->sun_path) - 1] = '\0';
> +		len = offsetof(struct sockaddr_un, sun_path) + strlen(name) + 1;
> +	} else {
> +		addr->sun_path[0] = '\0';
> +		/*

Nitpick: These comment lines are needlessly longer than 80 characters,
but otherwise, everything's fine.

Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>

> +		 * The abstract socket's name doesn't need to be NULL terminated.
> +		 * Actually, a trailing NULL would be considered part of the socket name.
> +		 */
> +#pragma GCC diagnostic push
> +#if WSTRINGOP_TRUNCATION
> +#pragma GCC diagnostic ignored "-Wstringop-truncation"
> +#endif
> +		strncpy(&addr->sun_path[1], &name[1], sizeof(addr->sun_path) - 1);
> +#pragma GCC diagnostic pop
> +		len = offsetof(struct sockaddr_un, sun_path) + strlen(name);
> +	}
> +	return len > sizeof(*addr) ? sizeof(*addr) : len;
> +}
> diff --git a/libmpathutil/uxsock.c b/libmpathutil/uxsock.c
> index 2135476..12c4608 100644
> --- a/libmpathutil/uxsock.c
> +++ b/libmpathutil/uxsock.c
> @@ -6,12 +6,15 @@
>   */
>  #include <stdio.h>
>  #include <stdlib.h>
> +#include <string.h>
>  #include <unistd.h>
>  #include <stdarg.h>
> +#include <stddef.h>
>  #include <fcntl.h>
>  #include <sys/ioctl.h>
>  #include <sys/types.h>
>  #include <sys/socket.h>
> +#include <sys/stat.h>
>  #include <sys/un.h>
>  #include <poll.h>
>  #include <signal.h>
> @@ -33,6 +36,8 @@
>  static int _recv_packet(int fd, char **buf, unsigned int timeout,
>  			ssize_t limit);
>  
> +#include "../libmpathcmd/mpath_fill_sockaddr.c"
> +
>  /*
>   * create a unix domain socket and start listening on it
>   * return a file descriptor open on the socket
> @@ -63,15 +68,7 @@ int ux_socket_listen(const char *name)
>  		return -1;
>  	}
>  
> -	memset(&addr, 0, sizeof(addr));
> -	addr.sun_family = AF_LOCAL;
> -	addr.sun_path[0] = '\0';
> -	len = strlen(name) + 1;
> -	if (len >= sizeof(addr.sun_path))
> -		len = sizeof(addr.sun_path) - 1;
> -	memcpy(&addr.sun_path[1], name, len);
> -
> -	len += sizeof(sa_family_t);
> +	len = mpath_fill_sockaddr__(&addr, name);
>  	if (bind(fd, (struct sockaddr *)&addr, len) == -1) {
>  		condlog(3, "Couldn't bind to ux_socket, error %d", errno);
>  		close(fd);
> diff --git a/multipathd/Makefile b/multipathd/Makefile
> index 997b40c..61cf1af 100644
> --- a/multipathd/Makefile
> +++ b/multipathd/Makefile
> @@ -41,7 +41,7 @@ ifeq ($(FPIN_SUPPORT),1)
>  OBJS += fpin_handlers.o
>  endif
>  
> -all : $(EXEC) $(CLI) $(MANPAGES) $(EXEC).service
> +all : $(EXEC) $(CLI) $(MANPAGES) $(EXEC).service $(EXEC).socket
>  
>  $(EXEC): $(OBJS) $(multipathdir)/libmultipath.so $(mpathcmddir)/libmpathcmd.so
>  	@echo building $@ because of $?
> @@ -78,7 +78,7 @@ uninstall:
>  	$(Q)$(RM) $(DESTDIR)$(unitdir)/$(EXEC).socket
>  
>  clean: dep_clean
> -	$(Q)$(RM) core *.o $(EXEC) $(CLI) $(MANPAGES) $(EXEC).service
> +	$(Q)$(RM) core *.o $(EXEC) $(CLI) $(MANPAGES) $(EXEC).service $(EXEC).socket
>  
>  include $(wildcard $(OBJS:.o=.d) $(CLI_OBJS:.o=.d))
>  
> diff --git a/multipathd/multipathd.socket b/multipathd/multipathd.socket.in
> similarity index 87%
> rename from multipathd/multipathd.socket
> rename to multipathd/multipathd.socket.in
> index 6a62f5f..c0e86c3 100644
> --- a/multipathd/multipathd.socket
> +++ b/multipathd/multipathd.socket.in
> @@ -7,7 +7,7 @@ ConditionVirtualization=!container
>  Before=sockets.target
>  
>  [Socket]
> -ListenStream=@/org/kernel/linux/storage/multipathd
> +ListenStream=@MPATH_SOCKET@
>  
>  [Install]
>  # Socket activation for multipathd is disabled by default.
> -- 
> 2.48.1