core/socket: do not assign another fd to SocketPort which already has a fd on deserialization

Otherwise, if a socket address is duplicated, then the previous fd is
closed.

Fixes #19843.

(cherry picked from commit 3da0caf5bbf3c8cab716c4d7adf0eb25907dc951)
(cherry picked from commit 11acee8a00f1e04952f86088078041849d8f9819)

1 files changed, 61 insertions, 25 deletions

diff --git a/src/core/socket.c b/src/core/socket.c
index 7f8ac4eae9..13d4020509 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -2634,13 +2634,6 @@ static int socket_serialize(Unit *u, FILE *f, FDSet *fds) {
         return 0;
 }
 
-static void socket_port_take_fd(SocketPort *p, FDSet *fds, int fd) {
-        assert(p);
-
-        safe_close(p->fd);
-        p->fd = fdset_remove(fds, fd);
-}
-
 static int socket_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
         Socket *s = SOCKET(u);
 
@@ -2702,13 +2695,20 @@ static int socket_deserialize_item(Unit *u, const char *key, const char *value,
 
                 if (sscanf(value, "%i %n", &fd, &skip) < 1 || fd < 0 || !fdset_contains(fds, fd))
                         log_unit_debug(u, "Failed to parse fifo value: %s", value);
-                else
+                else {
+                        bool found = false;
+
                         LIST_FOREACH(port, p, s->ports)
-                                if (p->type == SOCKET_FIFO &&
+                                if (p->fd < 0 &&
+                                    p->type == SOCKET_FIFO &&
                                     path_equal_or_files_same(p->path, value+skip, 0)) {
-                                        socket_port_take_fd(p, fds, fd);
+                                        p->fd = fdset_remove(fds, fd);
+                                        found = true;
                                         break;
                                 }
+                        if (!found)
+                                log_unit_debug(u, "No matching fifo socket found: %s", value+skip);
+                }
 
         } else if (streq(key, "special")) {
                 int fd, skip = 0;
@@ -2716,13 +2716,20 @@ static int socket_deserialize_item(Unit *u, const char *key, const char *value,
 
                 if (sscanf(value, "%i %n", &fd, &skip) < 1 || fd < 0 || !fdset_contains(fds, fd))
                         log_unit_debug(u, "Failed to parse special value: %s", value);
-                else
+                else {
+                        bool found = false;
+
                         LIST_FOREACH(port, p, s->ports)
-                                if (p->type == SOCKET_SPECIAL &&
+                                if (p->fd < 0 &&
+                                    p->type == SOCKET_SPECIAL &&
                                     path_equal_or_files_same(p->path, value+skip, 0)) {
-                                        socket_port_take_fd(p, fds, fd);
+                                        p->fd = fdset_remove(fds, fd);
+                                        found = true;
                                         break;
                                 }
+                        if (!found)
+                                log_unit_debug(u, "No matching special socket found: %s", value+skip);
+                }
 
         } else if (streq(key, "mqueue")) {
                 int fd, skip = 0;
@@ -2730,13 +2737,20 @@ static int socket_deserialize_item(Unit *u, const char *key, const char *value,
 
                 if (sscanf(value, "%i %n", &fd, &skip) < 1 || fd < 0 || !fdset_contains(fds, fd))
                         log_unit_debug(u, "Failed to parse mqueue value: %s", value);
-                else
+                else {
+                        bool found = false;
+
                         LIST_FOREACH(port, p, s->ports)
-                                if (p->type == SOCKET_MQUEUE &&
+                                if (p->fd < 0 &&
+                                    p->type == SOCKET_MQUEUE &&
                                     streq(p->path, value+skip)) {
-                                        socket_port_take_fd(p, fds, fd);
+                                        p->fd = fdset_remove(fds, fd);
+                                        found = true;
                                         break;
                                 }
+                        if (!found)
+                                log_unit_debug(u, "No matching mqueue socket found: %s", value+skip);
+                }
 
         } else if (streq(key, "socket")) {
                 int fd, type, skip = 0;
@@ -2744,12 +2758,20 @@ static int socket_deserialize_item(Unit *u, const char *key, const char *value,
 
                 if (sscanf(value, "%i %i %n", &fd, &type, &skip) < 2 || fd < 0 || type < 0 || !fdset_contains(fds, fd))
                         log_unit_debug(u, "Failed to parse socket value: %s", value);
-                else
+                else {
+                        bool found = false;
+
                         LIST_FOREACH(port, p, s->ports)
-                                if (socket_address_is(&p->address, value+skip, type)) {
-                                        socket_port_take_fd(p, fds, fd);
+                                if (p->fd < 0 &&
+                                    socket_address_is(&p->address, value+skip, type)) {
+                                        p->fd = fdset_remove(fds, fd);
+                                        found = true;
                                         break;
                                 }
+                        if (!found)
+                                log_unit_debug(u, "No matching %s socket found: %s",
+                                               socket_address_type_to_string(type), value+skip);
+                }
 
         } else if (streq(key, "netlink")) {
                 int fd, skip = 0;
@@ -2757,12 +2779,19 @@ static int socket_deserialize_item(Unit *u, const char *key, const char *value,
 
                 if (sscanf(value, "%i %n", &fd, &skip) < 1 || fd < 0 || !fdset_contains(fds, fd))
                         log_unit_debug(u, "Failed to parse socket value: %s", value);
-                else
+                else {
+                        bool found = false;
+
                         LIST_FOREACH(port, p, s->ports)
-                                if (socket_address_is_netlink(&p->address, value+skip)) {
-                                        socket_port_take_fd(p, fds, fd);
+                                if (p->fd < 0 &&
+                                    socket_address_is_netlink(&p->address, value+skip)) {
+                                        p->fd = fdset_remove(fds, fd);
+                                        found = true;
                                         break;
                                 }
+                        if (!found)
+                                log_unit_debug(u, "No matching netlink socket found: %s", value+skip);
+                }
 
         } else if (streq(key, "ffs")) {
                 int fd, skip = 0;
@@ -2770,13 +2799,20 @@ static int socket_deserialize_item(Unit *u, const char *key, const char *value,
 
                 if (sscanf(value, "%i %n", &fd, &skip) < 1 || fd < 0 || !fdset_contains(fds, fd))
                         log_unit_debug(u, "Failed to parse ffs value: %s", value);
-                else
+                else {
+                        bool found = false;
+
                         LIST_FOREACH(port, p, s->ports)
-                                if (p->type == SOCKET_USB_FUNCTION &&
+                                if (p->fd < 0 &&
+                                    p->type == SOCKET_USB_FUNCTION &&
                                     path_equal_or_files_same(p->path, value+skip, 0)) {
-                                        socket_port_take_fd(p, fds, fd);
+                                        p->fd = fdset_remove(fds, fd);
+                                        found = true;
                                         break;
                                 }
+                        if (!found)
+                                log_unit_debug(u, "No matching ffs socket found: %s", value+skip);
+                }
 
         } else
                 log_unit_debug(UNIT(s), "Unknown serialization key: %s", key);