coredump: collect all /proc data useful for bug reporting

[elogind.git] / src / core / busname.c

diff --git a/src/core/busname.c b/src/core/busname.c
index b3f7e0d5d5c42ad1f775ac914aac6a1f7f850909..8926c6bd946cd24c68d796d0f7d6a10191489366 100644 (file)
--- a/src/core/busname.c
+++ b/src/core/busname.c
@@ -19,6 +19,8 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include <sys/mman.h>
+
 #include "special.h"
 #include "bus-kernel.h"
 #include "bus-internal.h"
@@ -26,6 +28,7 @@
 #include "service.h"
 #include "dbus-busname.h"
 #include "busname.h"
+#include "kdbus.h"
 
 static const UnitActiveState state_translation_table[_BUSNAME_STATE_MAX] = {
         [BUSNAME_DEAD] = UNIT_INACTIVE,
@@ -290,14 +293,18 @@ static int busname_watch_fd(BusName *n) {
 }
 
 static int busname_open_fd(BusName *n) {
+        _cleanup_free_ char *path = NULL;
+        const char *mode;
+
         assert(n);
 
         if (n->starter_fd >= 0)
                 return 0;
 
-        n->starter_fd = bus_kernel_open_bus_fd(UNIT(n)->manager->running_as == SYSTEMD_SYSTEM ? "system" : "user");
+        mode = UNIT(n)->manager->running_as == SYSTEMD_SYSTEM ? "system" : "user";
+        n->starter_fd = bus_kernel_open_bus_fd(mode, &path);
         if (n->starter_fd < 0) {
-                log_warning_unit(UNIT(n)->id, "Failed to create starter fd: %s", strerror(-n->starter_fd));
+                log_warning_unit(UNIT(n)->id, "Failed to open %s: %s", path ?: "kdbus", strerror(-n->starter_fd));
                 return n->starter_fd;
         }
 
@@ -441,7 +448,7 @@ static void busname_enter_signal(BusName *n, BusNameState state, BusNameResult f
 
         r = unit_kill_context(UNIT(n),
                               &kill_context,
-                              state != BUSNAME_SIGTERM,
+                              state != BUSNAME_SIGTERM ? KILL_KILL : KILL_TERMINATE,
                               -1,
                               n->control_pid,
                               false);
@@ -720,6 +727,88 @@ _pure_ static const char *busname_sub_state_to_string(Unit *u) {
         return busname_state_to_string(BUSNAME(u)->state);
 }
 
+static int busname_peek_message(BusName *n) {
+        struct kdbus_cmd_recv cmd_recv = {
+                .flags = KDBUS_RECV_PEEK,
+        };
+        struct kdbus_cmd_free cmd_free = {};
+        const char *comm = NULL;
+        struct kdbus_item *d;
+        struct kdbus_msg *k;
+        size_t start, ps, sz, delta;
+        void *p = NULL;
+        pid_t pid = 0;
+        int r;
+
+        /* Generate a friendly debug log message about which process
+         * caused triggering of this bus name. This simply peeks the
+         * metadata of the first queued message and logs it. */
+
+        assert(n);
+
+        /* Let's shortcut things a bit, if debug logging is turned off
+         * anyway. */
+
+        if (log_get_max_level() < LOG_DEBUG)
+                return 0;
+
+        r = ioctl(n->starter_fd, KDBUS_CMD_MSG_RECV, &cmd_recv);
+        if (r < 0) {
+                if (errno == EINTR || errno == EAGAIN)
+                        return 0;
+
+                log_error_unit(UNIT(n)->id, "%s: Failed to query activation message: %m", UNIT(n)->id);
+                return -errno;
+        }
+
+        /* We map as late as possible, and unmap imemdiately after
+         * use. On 32bit address space is scarce and we want to be
+         * able to handle a lot of activator connections at the same
+         * time, and hence shouldn't keep the mmap()s around for
+         * longer than necessary. */
+
+        ps = page_size();
+        start = (cmd_recv.offset / ps) * ps;
+        delta = cmd_recv.offset - start;
+        sz = PAGE_ALIGN(delta + cmd_recv.msg_size);
+
+        p = mmap(NULL, sz, PROT_READ, MAP_SHARED, n->starter_fd, start);
+        if (p == MAP_FAILED) {
+                log_error_unit(UNIT(n)->id, "%s: Failed to map activation message: %m", UNIT(n)->id);
+                r = -errno;
+                goto finish;
+        }
+
+        k = (struct kdbus_msg *) ((uint8_t *) p + delta);
+        KDBUS_ITEM_FOREACH(d, k, items) {
+                switch (d->type) {
+
+                case KDBUS_ITEM_PIDS:
+                        pid = d->pids.pid;
+                        break;
+
+                case KDBUS_ITEM_PID_COMM:
+                        comm = d->str;
+                        break;
+                }
+        }
+
+        if (pid > 0)
+                log_debug_unit(UNIT(n)->id, "%s: Activation triggered by process " PID_FMT " (%s)", UNIT(n)->id, pid, strna(comm));
+
+        r = 0;
+
+finish:
+        if (p)
+                (void) munmap(p, sz);
+
+        cmd_free.offset = cmd_recv.offset;
+        if (ioctl(n->starter_fd, KDBUS_CMD_FREE, &cmd_free) < 0)
+                log_warning_unit(UNIT(n)->id, "Failed to free peeked message, ignoring: %m");
+
+        return r;
+}
+
 static int busname_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
         BusName *n = userdata;
 
@@ -737,6 +826,7 @@ static int busname_dispatch_io(sd_event_source *source, int fd, uint32_t revents
                 goto fail;
         }
 
+        busname_peek_message(n);
         busname_enter_running(n);
         return 0;
 fail:
@@ -906,14 +996,6 @@ static const char* const busname_result_table[_BUSNAME_RESULT_MAX] = {
 
 DEFINE_STRING_TABLE_LOOKUP(busname_result, BusNameResult);
 
-static const char* const busname_policy_access_table[_BUSNAME_POLICY_ACCESS_MAX] = {
-        [BUSNAME_POLICY_ACCESS_SEE] = "see",
-        [BUSNAME_POLICY_ACCESS_TALK] = "talk",
-        [BUSNAME_POLICY_ACCESS_OWN] = "own",
-};
-
-DEFINE_STRING_TABLE_LOOKUP(busname_policy_access, BusNamePolicyAccess);
-
 const UnitVTable busname_vtable = {
         .object_size = sizeof(BusName),