cgroup: make sure all our cgroup objects have a suffix and are properly escaped

Session objects will now get the .session suffix, user objects the .user
suffix, nspawn containers the .nspawn suffix.

This also changes the user cgroups to be named after the numeric UID
rather than the username, since this allows us the parse these paths
standalone without requiring access to the cgroup file system.

This also changes the mapping of instanced units to cgroups. Instead of
mapping foo@bar.service to the cgroup path /user/foo@.service/bar we
will now map it to /user/foo@.service/foo@bar.service, in order to
ensure that all our objects are properly suffixed in the tree.

1 files changed, 69 insertions, 93 deletions

diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c
index 7e7b379df8..4134e9fc67 100644
--- a/src/journal/journald-server.c
+++ b/src/journal/journald-server.c
@@ -31,10 +31,6 @@
 #include <systemd/sd-messages.h>
 #include <systemd/sd-daemon.h>
 
-#ifdef HAVE_LOGIND
-#include <systemd/sd-login.h>
-#endif
-
 #include "fileio.h"
 #include "mkdir.h"
 #include "hashmap.h"
@@ -505,26 +501,26 @@ static void dispatch_message_real(
                 const char *label, size_t label_len,
                 const char *unit_id) {
 
-        char pid[sizeof("_PID=") + DECIMAL_STR_MAX(ucred->pid)],
-                uid[sizeof("_UID=") + DECIMAL_STR_MAX(ucred->uid)],
-                gid[sizeof("_GID=") + DECIMAL_STR_MAX(ucred->gid)],
+        char pid[sizeof("_PID=") + DECIMAL_STR_MAX(pid_t)],
+                uid[sizeof("_UID=") + DECIMAL_STR_MAX(uid_t)],
+                gid[sizeof("_GID=") + DECIMAL_STR_MAX(gid_t)],
+                owner_uid[sizeof("_SYSTEMD_OWNER_UID=") + DECIMAL_STR_MAX(uid_t)],
                 source_time[sizeof("_SOURCE_REALTIME_TIMESTAMP=") + DECIMAL_STR_MAX(usec_t)],
                 boot_id[sizeof("_BOOT_ID=") + 32] = "_BOOT_ID=",
                 machine_id[sizeof("_MACHINE_ID=") + 32] = "_MACHINE_ID=";
-
-        _cleanup_free_ char *comm = NULL, *cmdline = NULL, *hostname = NULL,
-                *exe = NULL, *cgroup = NULL, *session = NULL,
-                *owner_uid = NULL, *unit = NULL, *selinux_context = NULL;
-
-#ifdef HAVE_AUDIT
-        _cleanup_free_ char *audit_session = NULL, *audit_loginuid = NULL;
-#endif
-
+        char *comm, *exe, *cmdline, *cgroup, *session, *unit, *selinux_context, *hostname;
         sd_id128_t id;
         int r;
-        char *t;
+        char *t, *c;
         uid_t realuid = 0, owner = 0, journal_uid;
         bool owner_valid = false;
+#ifdef HAVE_AUDIT
+        char audit_session[sizeof("_AUDIT_SESSION=") + DECIMAL_STR_MAX(uint32_t)],
+                audit_loginuid[sizeof("_AUDIT_LOGINUID=") + DECIMAL_STR_MAX(uid_t)];
+
+        uint32_t audit;
+        uid_t loginuid;
+#endif
 
         assert(s);
         assert(iovec);
@@ -532,130 +528,111 @@ static void dispatch_message_real(
         assert(n + N_IOVEC_META_FIELDS <= m);
 
         if (ucred) {
-#ifdef HAVE_AUDIT
-                uint32_t audit;
-                uid_t loginuid;
-#endif
-
                 realuid = ucred->uid;
 
-                snprintf(pid, sizeof(pid) - 1, "_PID=%lu", (unsigned long) ucred->pid);
-                char_array_0(pid);
+                sprintf(pid, "_PID=%lu", (unsigned long) ucred->pid);
                 IOVEC_SET_STRING(iovec[n++], pid);
 
-                snprintf(uid, sizeof(uid) - 1, "_UID=%lu", (unsigned long) ucred->uid);
-                char_array_0(uid);
+                sprintf(uid, "_UID=%lu", (unsigned long) ucred->uid);
                 IOVEC_SET_STRING(iovec[n++], uid);
 
-                snprintf(gid, sizeof(gid) - 1, "_GID=%lu", (unsigned long) ucred->gid);
-                char_array_0(gid);
+                sprintf(gid, "_GID=%lu", (unsigned long) ucred->gid);
                 IOVEC_SET_STRING(iovec[n++], gid);
 
                 r = get_process_comm(ucred->pid, &t);
                 if (r >= 0) {
-                        comm = strappend("_COMM=", t);
+                        comm = strappenda("_COMM=", t);
                         free(t);
-
-                        if (comm)
-                                IOVEC_SET_STRING(iovec[n++], comm);
+                        IOVEC_SET_STRING(iovec[n++], comm);
                 }
 
                 r = get_process_exe(ucred->pid, &t);
                 if (r >= 0) {
-                        exe = strappend("_EXE=", t);
+                        exe = strappenda("_EXE=", t);
                         free(t);
-
-                        if (exe)
-                                IOVEC_SET_STRING(iovec[n++], exe);
+                        IOVEC_SET_STRING(iovec[n++], exe);
                 }
 
                 r = get_process_cmdline(ucred->pid, 0, false, &t);
                 if (r >= 0) {
-                        cmdline = strappend("_CMDLINE=", t);
+                        cmdline = strappenda("_CMDLINE=", t);
                         free(t);
-
-                        if (cmdline)
-                                IOVEC_SET_STRING(iovec[n++], cmdline);
+                        IOVEC_SET_STRING(iovec[n++], cmdline);
                 }
 
 #ifdef HAVE_AUDIT
                 r = audit_session_from_pid(ucred->pid, &audit);
-                if (r >= 0)
-                        if (asprintf(&audit_session, "_AUDIT_SESSION=%lu", (unsigned long) audit) >= 0)
-                                IOVEC_SET_STRING(iovec[n++], audit_session);
+                if (r >= 0) {
+                        sprintf(audit_session, "_AUDIT_SESSION=%lu", (unsigned long) audit);
+                        IOVEC_SET_STRING(iovec[n++], audit_session);
+                }
 
                 r = audit_loginuid_from_pid(ucred->pid, &loginuid);
-                if (r >= 0)
-                        if (asprintf(&audit_loginuid, "_AUDIT_LOGINUID=%lu", (unsigned long) loginuid) >= 0)
-                                IOVEC_SET_STRING(iovec[n++], audit_loginuid);
-#endif
-
-                r = cg_pid_get_path(NULL, ucred->pid, &t);
                 if (r >= 0) {
-                        cgroup = strappend("_SYSTEMD_CGROUP=", t);
-                        free(t);
-
-                        if (cgroup)
-                                IOVEC_SET_STRING(iovec[n++], cgroup);
+                        sprintf(audit_loginuid, "_AUDIT_LOGINUID=%lu", (unsigned long) loginuid);
+                        IOVEC_SET_STRING(iovec[n++], audit_loginuid);
                 }
+#endif
 
-#ifdef HAVE_LOGIND
-                r = cg_pid_get_session(ucred->pid, &t);
+                r = cg_pid_get_path_shifted(ucred->pid, NULL, &c);
                 if (r >= 0) {
-                        session = strappend("_SYSTEMD_SESSION=", t);
-                        free(t);
+                        cgroup = strappenda("_SYSTEMD_CGROUP=", c);
+                        IOVEC_SET_STRING(iovec[n++], cgroup);
 
-                        if (session)
+                        r = cg_path_get_session(c, &t);
+                        if (r >= 0) {
+                                session = strappenda("_SYSTEMD_SESSION=", t);
+                                free(t);
                                 IOVEC_SET_STRING(iovec[n++], session);
-                }
+                        }
 
-                if (sd_pid_get_owner_uid(ucred->pid, &owner) >= 0) {
-                        owner_valid = true;
-                        if (asprintf(&owner_uid, "_SYSTEMD_OWNER_UID=%lu", (unsigned long) owner) >= 0)
+                        if (cg_path_get_owner_uid(c, &owner) >= 0) {
+                                owner_valid = true;
+
+                                sprintf(owner_uid, "_SYSTEMD_OWNER_UID=%lu", (unsigned long) owner);
                                 IOVEC_SET_STRING(iovec[n++], owner_uid);
-                }
-#endif
+                        }
 
-                if (cg_pid_get_unit(ucred->pid, &t) >= 0) {
-                        unit = strappend("_SYSTEMD_UNIT=", t);
-                        free(t);
-                } else if (cg_pid_get_user_unit(ucred->pid, &t) >= 0) {
-                        unit = strappend("_SYSTEMD_USER_UNIT=", t);
-                        free(t);
-                } else if (unit_id) {
-                        if (session)
-                                unit = strappend("_SYSTEMD_USER_UNIT=", unit_id);
-                        else
-                                unit = strappend("_SYSTEMD_UNIT=", unit_id);
+                        if (cg_path_get_unit(c, &t) >= 0) {
+                                unit = strappenda("_SYSTEMD_UNIT=", t);
+                                free(t);
+                        } else if (cg_path_get_user_unit(c, &t) >= 0) {
+                                unit = strappenda("_SYSTEMD_USER_UNIT=", t);
+                                free(t);
+                        } else if (unit_id) {
+                                if (session)
+                                        unit = strappenda("_SYSTEMD_USER_UNIT=", unit_id);
+                                else
+                                        unit = strappenda("_SYSTEMD_UNIT=", unit_id);
+                        } else
+                                unit = NULL;
+
+                        if (unit)
+                                IOVEC_SET_STRING(iovec[n++], unit);
+
+                        free(c);
                 }
 
-                if (unit)
-                        IOVEC_SET_STRING(iovec[n++], unit);
-
 #ifdef HAVE_SELINUX
                 if (label) {
-                        selinux_context = malloc(sizeof("_SELINUX_CONTEXT=") + label_len);
-                        if (selinux_context) {
-                                *((char*) mempcpy(stpcpy(selinux_context, "_SELINUX_CONTEXT="), label, label_len)) = 0;
-                                IOVEC_SET_STRING(iovec[n++], selinux_context);
-                        }
+                        selinux_context = alloca(sizeof("_SELINUX_CONTEXT=") + label_len);
+
+                        *((char*) mempcpy(stpcpy(selinux_context, "_SELINUX_CONTEXT="), label, label_len)) = 0;
+                        IOVEC_SET_STRING(iovec[n++], selinux_context);
                 } else {
                         security_context_t con;
 
                         if (getpidcon(ucred->pid, &con) >= 0) {
-                                selinux_context = strappend("_SELINUX_CONTEXT=", con);
-                                if (selinux_context)
-                                        IOVEC_SET_STRING(iovec[n++], selinux_context);
+                                selinux_context = strappenda("_SELINUX_CONTEXT=", con);
                                 freecon(con);
+                                IOVEC_SET_STRING(iovec[n++], selinux_context);
                         }
                 }
 #endif
         }
 
         if (tv) {
-                snprintf(source_time, sizeof(source_time) - 1, "_SOURCE_REALTIME_TIMESTAMP=%llu",
-                         (unsigned long long) timeval_load(tv));
-                char_array_0(source_time);
+                sprintf(source_time, "_SOURCE_REALTIME_TIMESTAMP=%llu", (unsigned long long) timeval_load(tv));
                 IOVEC_SET_STRING(iovec[n++], source_time);
         }
 
@@ -676,10 +653,9 @@ static void dispatch_message_real(
 
         t = gethostname_malloc();
         if (t) {
-                hostname = strappend("_HOSTNAME=", t);
+                hostname = strappenda("_HOSTNAME=", t);
                 free(t);
-                if (hostname)
-                        IOVEC_SET_STRING(iovec[n++], hostname);
+                IOVEC_SET_STRING(iovec[n++], hostname);
         }
 
         assert(n <= m);