sd-bus: expose ppid field

kdbus has been passing us the ppid file for a while, actually make use
of it.

6 files changed, 52 insertions, 5 deletions

diff --git a/src/libsystemd/libsystemd.sym.m4 b/src/libsystemd/libsystemd.sym.m4
index 1b50486cfa..f2dfec7f08 100644
--- a/src/libsystemd/libsystemd.sym.m4
+++ b/src/libsystemd/libsystemd.sym.m4
@@ -326,6 +326,7 @@ global:
         sd_bus_creds_get_uid;
         sd_bus_creds_get_gid;
         sd_bus_creds_get_pid;
+        sd_bus_creds_get_ppid;
         sd_bus_creds_get_tid;
         sd_bus_creds_get_comm;
         sd_bus_creds_get_tid_comm;
diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c
index 25510f00c7..1084ddc9ca 100644
--- a/src/libsystemd/sd-bus/bus-control.c
+++ b/src/libsystemd/sd-bus/bus-control.c
@@ -413,6 +413,11 @@ static int bus_populate_creds_from_items(
                                 c->mask |= SD_BUS_CREDS_TID;
                         }
 
+                        if (mask & SD_BUS_CREDS_PPID && item->pids.ppid > 0) {
+                                c->ppid = (pid_t) item->pids.ppid;
+                                c->mask |= SD_BUS_CREDS_PPID;
+                        }
+
                         break;
 
                 case KDBUS_ITEM_CREDS:
@@ -644,7 +649,8 @@ int bus_get_name_creds_kdbus(
          * the bits we want, then ask for the PID/TID so that we
          * can read the rest from /proc. */
         if ((mask & SD_BUS_CREDS_AUGMENT) &&
-            (mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
+            (mask & (SD_BUS_CREDS_PPID|
+                     SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
                      SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID|
                      SD_BUS_CREDS_COMM|SD_BUS_CREDS_TID_COMM|SD_BUS_CREDS_EXE|SD_BUS_CREDS_CMDLINE|
                      SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID|
@@ -910,7 +916,8 @@ static int bus_get_owner_creds_kdbus(sd_bus *bus, uint64_t mask, sd_bus_creds **
          * to get the bits we want, then ask for the PID/TID so that we
          * can read the rest from /proc. */
         if ((mask & SD_BUS_CREDS_AUGMENT) &&
-            (mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
+            (mask & (SD_BUS_CREDS_PPID|
+                     SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
                      SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID|
                      SD_BUS_CREDS_COMM|SD_BUS_CREDS_TID_COMM|SD_BUS_CREDS_EXE|SD_BUS_CREDS_CMDLINE|
                      SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID|
diff --git a/src/libsystemd/sd-bus/bus-creds.c b/src/libsystemd/sd-bus/bus-creds.c
index b00b5308a8..6cb47f55ce 100644
--- a/src/libsystemd/sd-bus/bus-creds.c
+++ b/src/libsystemd/sd-bus/bus-creds.c
@@ -293,6 +293,17 @@ _public_ int sd_bus_creds_get_pid(sd_bus_creds *c, pid_t *pid) {
         return 0;
 }
 
+_public_ int sd_bus_creds_get_ppid(sd_bus_creds *c, pid_t *ppid) {
+        assert_return(c, -EINVAL);
+        assert_return(ppid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_PPID))
+                return -ENODATA;
+
+        *ppid = c->ppid;
+        return 0;
+}
+
 _public_ int sd_bus_creds_get_tid(sd_bus_creds *c, pid_t *tid) {
         assert_return(c, -EINVAL);
         assert_return(tid, -EINVAL);
@@ -728,7 +739,8 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
                 c->mask |= SD_BUS_CREDS_TID;
         }
 
-        if (missing & (SD_BUS_CREDS_UID | SD_BUS_CREDS_EUID | SD_BUS_CREDS_SUID | SD_BUS_CREDS_FSUID |
+        if (missing & (SD_BUS_CREDS_PPID |
+                       SD_BUS_CREDS_UID | SD_BUS_CREDS_EUID | SD_BUS_CREDS_SUID | SD_BUS_CREDS_FSUID |
                        SD_BUS_CREDS_GID | SD_BUS_CREDS_EGID | SD_BUS_CREDS_SGID | SD_BUS_CREDS_FSGID |
                        SD_BUS_CREDS_SUPPLEMENTARY_GIDS |
                        SD_BUS_CREDS_EFFECTIVE_CAPS | SD_BUS_CREDS_INHERITABLE_CAPS |
@@ -751,6 +763,20 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
                         FOREACH_LINE(line, f, return -errno) {
                                 truncate_nl(line);
 
+                                if (missing & SD_BUS_CREDS_PPID) {
+                                        p = startswith(line, "PPid:");
+                                        if (p) {
+                                                p += strspn(p, WHITESPACE);
+
+                                                r = parse_pid(p, &c->ppid);
+                                                if (r < 0)
+                                                        return r;
+
+                                                c->mask |= SD_BUS_CREDS_PPID;
+                                                continue;
+                                        }
+                                }
+
                                 if (missing & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID)) {
                                         p = startswith(line, "Uid:");
                                         if (p) {
@@ -1015,6 +1041,11 @@ int bus_creds_extend_by_pid(sd_bus_creds *c, uint64_t mask, sd_bus_creds **ret)
                 n->mask |= SD_BUS_CREDS_TID;
         }
 
+        if (c->mask & mask & SD_BUS_CREDS_PPID) {
+                n->ppid = c->ppid;
+                n->mask |= SD_BUS_CREDS_PPID;
+        }
+
         if (c->mask & mask & SD_BUS_CREDS_UID) {
                 n->uid = c->uid;
                 n->mask |= SD_BUS_CREDS_UID;
diff --git a/src/libsystemd/sd-bus/bus-creds.h b/src/libsystemd/sd-bus/bus-creds.h
index 74062a583d..720450625c 100644
--- a/src/libsystemd/sd-bus/bus-creds.h
+++ b/src/libsystemd/sd-bus/bus-creds.h
@@ -44,6 +44,7 @@ struct sd_bus_creds {
         gid_t *supplementary_gids;
         unsigned n_supplementary_gids;
 
+        pid_t ppid;
         pid_t pid;
         pid_t tid;
 
diff --git a/src/libsystemd/sd-bus/bus-dump.c b/src/libsystemd/sd-bus/bus-dump.c
index 9165dd7d5a..13ff8b956a 100644
--- a/src/libsystemd/sd-bus/bus-dump.c
+++ b/src/libsystemd/sd-bus/bus-dump.c
@@ -362,8 +362,10 @@ int bus_creds_dump(sd_bus_creds *c, FILE *f, bool terse) {
                 fprintf(f, "%sPID=%s"PID_FMT"%s", prefix, color, c->pid, suffix);
         if (c->mask & SD_BUS_CREDS_TID)
                 fprintf(f, "%sTID=%s"PID_FMT"%s", prefix, color, c->tid, suffix);
+        if (c->mask & SD_BUS_CREDS_PPID)
+                fprintf(f, "%sPPID=%s"PID_FMT"%s", prefix, color, c->ppid, suffix);
 
-        if (terse && ((c->mask & (SD_BUS_CREDS_PID|SD_BUS_CREDS_TID))))
+        if (terse && ((c->mask & (SD_BUS_CREDS_PID|SD_BUS_CREDS_TID|SD_BUS_CREDS_PPID))))
                 fputs("\n", f);
 
         if (c->mask & SD_BUS_CREDS_UID)
diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index 0062e66d39..a8c04b98a9 100644
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -595,6 +595,11 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
                                 m->creds.mask |= SD_BUS_CREDS_TID & bus->creds_mask;
                         }
 
+                        if (d->pids.ppid > 0) {
+                                m->creds.ppid = (pid_t) d->pids.ppid;
+                                m->creds.mask |= SD_BUS_CREDS_PPID & bus->creds_mask;
+                        }
+
                         break;
 
                 case KDBUS_ITEM_CREDS:
@@ -1506,7 +1511,7 @@ uint64_t attach_flags_to_kdbus(uint64_t mask) {
                     SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID))
                 m |= KDBUS_ATTACH_CREDS;
 
-        if (mask & (SD_BUS_CREDS_PID|SD_BUS_CREDS_TID))
+        if (mask & (SD_BUS_CREDS_PID|SD_BUS_CREDS_TID|SD_BUS_CREDS_PPID))
                 m |= KDBUS_ATTACH_PIDS;
 
         if (mask & SD_BUS_CREDS_COMM)