systemd-analyze: make dump work for large # of units

If there is a large number of units, the size of the generated dump
string can overstep DBus message size limit. So let's pass that string
via a fd.

diff --git a/src/analyze/analyze.c b/src/analyze/analyze.c
index 5e1766b0536eaa781c288e84df10571e37471b3f..580bc30e1210c6d5f04a1a0df94f644d8a00489b 100644 (file)
--- a/src/analyze/analyze.c
+++ b/src/analyze/analyze.c
@@ -21,6 +21,8 @@
 #include "calendarspec.h"
 #include "def.h"
 #include "conf-files.h"
+#include "copy.h"
+#include "fd-util.h"
 #include "glob-util.h"
 #include "hashmap.h"
 #include "locale-util.h"
@@ -1279,11 +1281,39 @@ static int dot(int argc, char *argv[], void *userdata) {
         return 0;
 }
 
+static int dump_fallback(sd_bus *bus) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        const char *text = NULL;
+        int r;
+
+        assert(bus);
+
+        r = sd_bus_call_method(
+                        bus,
+                        "org.freedesktop.systemd1",
+                        "/org/freedesktop/systemd1",
+                        "org.freedesktop.systemd1.Manager",
+                        "Dump",
+                        &error,
+                        &reply,
+                        NULL);
+        if (r < 0)
+                return log_error_errno(r, "Failed to issue method call Dump: %s", bus_error_message(&error, r));
+
+        r = sd_bus_message_read(reply, "s", &text);
+        if (r < 0)
+                return bus_log_parse_error(r);
+
+        fputs(text, stdout);
+        return 0;
+}
+
 static int dump(int argc, char *argv[], void *userdata) {
         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
-        const char *text = NULL;
+        int fd = -1;
         int r;
 
         r = acquire_bus(&bus, NULL);
@@ -1292,24 +1322,32 @@ static int dump(int argc, char *argv[], void *userdata) {
 
         (void) pager_open(arg_no_pager, false);
 
+        if (!sd_bus_can_send(bus, SD_BUS_TYPE_UNIX_FD))
+                return dump_fallback(bus);
+
         r = sd_bus_call_method(
                         bus,
                         "org.freedesktop.systemd1",
                         "/org/freedesktop/systemd1",
                         "org.freedesktop.systemd1.Manager",
-                        "Dump",
+                        "DumpByFileDescriptor",
                         &error,
                         &reply,
                         NULL);
-        if (r < 0)
-                return log_error_errno(r, "Failed to issue method call: %s", bus_error_message(&error, r));
+        if (r < 0) {
+                /* fall back to Dump if DumpByFileDescriptor is not supported */
+                if (!IN_SET(r, -EACCES, -EBADR))
+                        return log_error_errno(r, "Failed to issue method call DumpByFileDescriptor: %s", bus_error_message(&error, r));
 
-        r = sd_bus_message_read(reply, "s", &text);
+                return dump_fallback(bus);
+        }
+
+        r = sd_bus_message_read(reply, "h", &fd);
         if (r < 0)
                 return bus_log_parse_error(r);
 
-        fputs(text, stdout);
-        return 0;
+        fflush(stdout);
+        return copy_bytes(fd, STDOUT_FILENO, (uint64_t) -1, 0);
 }
 
 static int cat_config(int argc, char *argv[], void *userdata) {

diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c
index ced5d06bd4a8602928836e34a4cea88f701f37d9..8a784747bb4a3f13cf88a66232d124d8398ade7b 100644 (file)
--- a/src/core/dbus-manager.c
+++ b/src/core/dbus-manager.c
@@ -1321,7 +1321,7 @@ static int method_unsubscribe(sd_bus_message *message, void *userdata, sd_bus_er
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_dump(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+static int dump_impl(sd_bus_message *message, void *userdata, sd_bus_error *error, int (*reply)(sd_bus_message *, char *)) {
         _cleanup_free_ char *dump = NULL;
         Manager *m = userdata;
         int r;
@@ -1339,9 +1339,31 @@ static int method_dump(sd_bus_message *message, void *userdata, sd_bus_error *er
         if (r < 0)
                 return r;
 
+        return reply(message, dump);
+}
+
+static int reply_dump(sd_bus_message *message, char *dump) {
         return sd_bus_reply_method_return(message, "s", dump);
 }
 
+static int method_dump(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        return dump_impl(message, userdata, error, reply_dump);
+}
+
+static int reply_dump_by_fd(sd_bus_message *message, char *dump) {
+        _cleanup_close_ int fd = -1;
+
+        fd = acquire_data_fd(dump, strlen(dump), 0);
+        if (fd < 0)
+                return fd;
+
+        return sd_bus_reply_method_return(message, "h", fd);
+}
+
+static int method_dump_by_fd(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        return dump_impl(message, userdata, error, reply_dump_by_fd);
+}
+
 static int method_refuse_snapshot(sd_bus_message *message, void *userdata, sd_bus_error *error) {
         return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Support for snapshots has been removed.");
 }
@@ -2598,6 +2620,7 @@ const sd_bus_vtable bus_manager_vtable[] = {
         SD_BUS_METHOD("Subscribe", NULL, NULL, method_subscribe, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("Unsubscribe", NULL, NULL, method_unsubscribe, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("Dump", NULL, "s", method_dump, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("DumpByFileDescriptor", NULL, "h", method_dump_by_fd, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("CreateSnapshot", "sb", "o", method_refuse_snapshot, SD_BUS_VTABLE_UNPRIVILEGED|SD_BUS_VTABLE_HIDDEN),
         SD_BUS_METHOD("RemoveSnapshot", "s", NULL, method_refuse_snapshot, SD_BUS_VTABLE_UNPRIVILEGED|SD_BUS_VTABLE_HIDDEN),
         SD_BUS_METHOD("Reload", NULL, NULL, method_reload, SD_BUS_VTABLE_UNPRIVILEGED),

diff --git a/src/core/org.freedesktop.systemd1.conf b/src/core/org.freedesktop.systemd1.conf
index 0114128a5734f774012f7d7cd845152de3cfc92b..415b3f5d84f8759e0cd903412828b51d2c9a836c 100644 (file)
--- a/src/core/org.freedesktop.systemd1.conf
+++ b/src/core/org.freedesktop.systemd1.conf
@@ -116,6 +116,10 @@
                        send_interface="org.freedesktop.systemd1.Manager"
                        send_member="Dump"/>
 
+                <allow send_destination="org.freedesktop.systemd1"
+                       send_interface="org.freedesktop.systemd1.Manager"
+                       send_member="DumpByFileDescriptor"/>
+
                 <allow send_destination="org.freedesktop.systemd1"
                        send_interface="org.freedesktop.systemd1.Manager"
                        send_member="ListUnitFiles"/>