kdbus: when running in a container, don't complain that we cannot write to /sys

[elogind.git] / src / libsystemd / sd-bus / bus-kernel.c

diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index 3a3ed200a0782c0a48f8c8846b96329f47eb5137..84fb4bdf2b4af185c8ab6f0de7523c96d5a6ce79 100644 (file)
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -32,6 +32,8 @@
 #include "util.h"
 #include "strv.h"
 #include "memfd-util.h"
+#include "cgroup-util.h"
+#include "fileio.h"
 
 #include "bus-internal.h"
 #include "bus-message.h"
@@ -39,7 +41,6 @@
 #include "bus-bloom.h"
 #include "bus-util.h"
 #include "bus-label.h"
-#include "cgroup-util.h"
 
 #define UNIQUE_NAME_MAX (3+DECIMAL_STR_MAX(uint64_t))
 
@@ -717,6 +718,14 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
                 }
         }
 
+        /* If we requested the list of well-known names to be appended
+         * and the sender had none no item for it will be
+         * attached. However, this does *not* mean that we the kernel
+         * didn't want to provide this information to us. Hence, let's
+         * explicitly mark this information as available if it was
+         * requested. */
+        m->creds.mask |= bus->creds_mask & SD_BUS_CREDS_WELL_KNOWN_NAMES;
+
         r = bus_message_parse_fields(m);
         if (r < 0)
                 goto fail;
@@ -1788,3 +1797,38 @@ int bus_kernel_realize_attach_flags(sd_bus *bus) {
 
         return 0;
 }
+
+int bus_kernel_fix_attach_mask(void) {
+        _cleanup_free_ char *mask = NULL;
+        uint64_t m = (uint64_t) -1;
+        char buf[2+16+2];
+        int r;
+
+        /* By default we don't want any kdbus metadata fields to be
+         * suppressed, hence we reset the kernel mask for it to
+         * (uint64_t) -1. This is overridable via a kernel command
+         * line option, however. */
+
+        r = get_proc_cmdline_key("systemd.kdbus_attach_flags_mask=", &mask);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to read kernel command line: %m");
+
+        if (mask) {
+                const char *p = mask;
+
+                if (startswith(p, "0x"))
+                        p += 2;
+
+                if (sscanf(p, "%" PRIx64, &m) != 1)
+                        log_warning("Couldn't parse systemd.kdbus_attach_flags_mask= kernel command line parameter.");
+        }
+
+        sprintf(buf, "0x%" PRIx64 "\n", m);
+        r = write_string_file("/sys/module/kdbus/parameters/attach_flags_mask", buf);
+        if (r < 0)
+                return log_full_errno(
+                                r == -EROFS ? LOG_DEBUG : LOG_WARNING, r,
+                                "Failed to write kdbus attach mask: %m");
+
+        return 0;
+}