terminal-util: introduce openpt_allocate()

Allocating a pty is done in a couple of places so let's introduce a new helper
which does the job.

Also the new function, as well as openpt_in_namespace(), returns both pty
master and slave so the callers don't need to know about the pty slave
allocation details.

For the same reasons machine_openpt() prototype has also been changed to return
both pty master and slave so callers don't need to allocate a pty slave which
might be in a different namespace.

Finally openpt_in_namespace() has been renamed into
openpt_allocate_in_namespace().

5 files changed, 55 insertions, 45 deletions

diff --git a/src/basic/terminal-util.c b/src/basic/terminal-util.c
index 3a0d16a74f..aa69bede6f 100644
--- a/src/basic/terminal-util.c
+++ b/src/basic/terminal-util.c
@@ -1049,7 +1049,34 @@ int ptsname_malloc(int fd, char **ret) {
         }
 }
 
-int ptsname_namespace(int pty, char **ret) {
+int openpt_allocate(int flags, char **ret_slave) {
+        _cleanup_close_ int fd = -1;
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        fd = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        if (ret_slave) {
+                r = ptsname_malloc(fd, &p);
+                if (r < 0)
+                        return r;
+
+                if (!path_startswith(p, "/dev/pts/"))
+                        return -EINVAL;
+        }
+
+        if (unlockpt(fd) < 0)
+                return -errno;
+
+        if (ret_slave)
+                *ret_slave = TAKE_PTR(p);
+
+        return TAKE_FD(fd);
+}
+
+static int ptsname_namespace(int pty, char **ret) {
         int no = -1, r;
 
         /* Like ptsname(), but doesn't assume that the path is
@@ -1068,8 +1095,8 @@ int ptsname_namespace(int pty, char **ret) {
         return 0;
 }
 
-int openpt_in_namespace(pid_t pid, int flags) {
-        _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
+int openpt_allocate_in_namespace(pid_t pid, int flags, char **ret_slave) {
+        _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1, fd = -1;
         _cleanup_close_pair_ int pair[2] = { -1, -1 };
         pid_t child;
         int r;
@@ -1088,18 +1115,13 @@ int openpt_in_namespace(pid_t pid, int flags) {
         if (r < 0)
                 return r;
         if (r == 0) {
-                int master;
-
                 pair[0] = safe_close(pair[0]);
 
-                master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
-                if (master < 0)
-                        _exit(EXIT_FAILURE);
-
-                if (unlockpt(master) < 0)
+                fd = openpt_allocate(flags, NULL);
+                if (fd < 0)
                         _exit(EXIT_FAILURE);
 
-                if (send_one_fd(pair[1], master, 0) < 0)
+                if (send_one_fd(pair[1], fd, 0) < 0)
                         _exit(EXIT_FAILURE);
 
                 _exit(EXIT_SUCCESS);
@@ -1113,7 +1135,17 @@ int openpt_in_namespace(pid_t pid, int flags) {
         if (r != EXIT_SUCCESS)
                 return -EIO;
 
-        return receive_one_fd(pair[0], 0);
+        fd = receive_one_fd(pair[0], 0);
+        if (fd < 0)
+                return fd;
+
+        if (ret_slave) {
+                r = ptsname_namespace(fd, ret_slave);
+                if (r < 0)
+                        return r;
+        }
+
+        return TAKE_FD(fd);
 }
 
 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
diff --git a/src/basic/terminal-util.h b/src/basic/terminal-util.h
index 87d09f8759..6e5b273c75 100644
--- a/src/basic/terminal-util.h
+++ b/src/basic/terminal-util.h
@@ -151,9 +151,9 @@ int getttyname_malloc(int fd, char **r);
 int getttyname_harder(int fd, char **r);
 
 int ptsname_malloc(int fd, char **ret);
-int ptsname_namespace(int pty, char **ret);
 
-int openpt_in_namespace(pid_t pid, int flags);
+int openpt_allocate(int flags, char **ret_slave);
+int openpt_allocate_in_namespace(pid_t pid, int flags, char **ret_slave);
 int open_terminal_in_namespace(pid_t pid, const char *name, int mode);
 
 int vt_default_utf8(void);
diff --git a/src/machine/machine-dbus.c b/src/machine/machine-dbus.c
index 1ee878055e..b89e6046d9 100644
--- a/src/machine/machine-dbus.c
+++ b/src/machine/machine-dbus.c
@@ -423,14 +423,10 @@ int bus_machine_method_open_pty(sd_bus_message *message, void *userdata, sd_bus_
         if (r == 0)
                 return 1; /* Will call us back */
 
-        master = machine_openpt(m, O_RDWR|O_NOCTTY|O_CLOEXEC);
+        master = machine_openpt(m, O_RDWR|O_NOCTTY|O_CLOEXEC, &pty_name);
         if (master < 0)
                 return master;
 
-        r = ptsname_namespace(master, &pty_name);
-        if (r < 0)
-                return r;
-
         r = sd_bus_message_new_method_return(message, &reply);
         if (r < 0)
                 return r;
@@ -514,17 +510,12 @@ int bus_machine_method_open_login(sd_bus_message *message, void *userdata, sd_bu
         if (r == 0)
                 return 1; /* Will call us back */
 
-        master = machine_openpt(m, O_RDWR|O_NOCTTY|O_CLOEXEC);
+        master = machine_openpt(m, O_RDWR|O_NOCTTY|O_CLOEXEC, &pty_name);
         if (master < 0)
                 return master;
 
-        r = ptsname_namespace(master, &pty_name);
-        if (r < 0)
-                return r;
-
         p = path_startswith(pty_name, "/dev/pts/");
-        if (!p)
-                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "PTS name %s is invalid", pty_name);
+        assert(p);
 
         r = container_bus_new(m, error, &allocated_bus);
         if (r < 0)
@@ -630,14 +621,10 @@ int bus_machine_method_open_shell(sd_bus_message *message, void *userdata, sd_bu
         if (r == 0)
                 return 1; /* Will call us back */
 
-        master = machine_openpt(m, O_RDWR|O_NOCTTY|O_CLOEXEC);
+        master = machine_openpt(m, O_RDWR|O_NOCTTY|O_CLOEXEC, &pty_name);
         if (master < 0)
                 return master;
 
-        r = ptsname_namespace(master, &pty_name);
-        if (r < 0)
-                return r;
-
         p = path_startswith(pty_name, "/dev/pts/");
         assert(p);
 
diff --git a/src/machine/machine.c b/src/machine/machine.c
index b916d038d7..ef8ccd98fb 100644
--- a/src/machine/machine.c
+++ b/src/machine/machine.c
@@ -530,29 +530,20 @@ int machine_kill(Machine *m, KillWho who, int signo) {
         return manager_kill_unit(m->manager, m->unit, signo, NULL);
 }
 
-int machine_openpt(Machine *m, int flags) {
+int machine_openpt(Machine *m, int flags, char **ret_slave) {
         assert(m);
 
         switch (m->class) {
 
-        case MACHINE_HOST: {
-                int fd;
-
-                fd = posix_openpt(flags);
-                if (fd < 0)
-                        return -errno;
-
-                if (unlockpt(fd) < 0)
-                        return -errno;
+        case MACHINE_HOST:
 
-                return fd;
-        }
+                return openpt_allocate(flags, ret_slave);
 
         case MACHINE_CONTAINER:
                 if (m->leader <= 0)
                         return -EINVAL;
 
-                return openpt_in_namespace(m->leader, flags);
+                return openpt_allocate_in_namespace(m->leader, flags, ret_slave);
 
         default:
                 return -EOPNOTSUPP;
diff --git a/src/machine/machine.h b/src/machine/machine.h
index 9ff9a65671..f7471be8f5 100644
--- a/src/machine/machine.h
+++ b/src/machine/machine.h
@@ -89,7 +89,7 @@ MachineState machine_state_from_string(const char *s) _pure_;
 const char *kill_who_to_string(KillWho k) _const_;
 KillWho kill_who_from_string(const char *s) _pure_;
 
-int machine_openpt(Machine *m, int flags);
+int machine_openpt(Machine *m, int flags, char **ret_slave);
 int machine_open_terminal(Machine *m, const char *path, int mode);
 
 int machine_get_uid_shift(Machine *m, uid_t *ret);