From 6772555b226a116bff07b7d8af28b16032273866 Mon Sep 17 00:00:00 2001

From: David Tardon <dtardon@redhat.com>

Date: Wed, 9 May 2018 09:35:52 +0200

Subject: [PATCH] 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.

(cherry picked from commit c0a1bfacfea9c65ea79fd07682a5b60b5d711a33)

Resolves: #1446095

---

 src/analyze/analyze.c                  | 57 ++++++++++++++++++++++----

 src/core/dbus-manager.c                | 26 +++++++++++-

 src/core/org.freedesktop.systemd1.conf |  4 ++

 3 files changed, 76 insertions(+), 11 deletions(-)

diff --git a/src/analyze/analyze.c b/src/analyze/analyze.c

index ff84f6894f..7116aaa88d 100644

--- a/src/analyze/analyze.c

+++ b/src/analyze/analyze.c

@@ -29,6 +29,7 @@

 #include "sd-bus.h"

 #include "bus-util.h"

 #include "bus-error.h"

+#include "copy.h"

 #include "install.h"

 #include "log.h"

 #include "build.h"

@@ -1096,12 +1097,42 @@ static int dot(sd_bus *bus, char* patterns[]) {

         return 0;

 }

-static int dump(sd_bus *bus, char **args) {

-        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;

-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;

+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,

+                        "");

+        if (r < 0) {

+                log_error("Failed to issue method call Dump: %s", bus_error_message(&error, -r));

+                return 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(sd_bus *bus, char **args) {

+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;

+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;

+        int fd = -1;

+        int r;

+

         if (!strv_isempty(args)) {

                 log_error("Too many arguments.");

                 return -E2BIG;

@@ -1109,26 +1140,34 @@ static int dump(sd_bus *bus, char **args) {

         pager_open_if_enabled();

+        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,

                        "");

         if (r < 0) {

-                log_error("Failed issue method call: %s", bus_error_message(&error, -r));

-                return r;

+                /* fall back to Dump if DumpByFileDescriptor is not supported */

+                if (!IN_SET(r, -EACCES, -EBADR)) {

+                        log_error("Failed to issue method call DumpByFileDescriptor: %s", bus_error_message(&error, -r));

+                        return r;

+                }

+

+                return dump_fallback(bus);

         }

-        r = sd_bus_message_read(reply, "s", &text);

+        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 set_log_level(sd_bus *bus, char **args) {

diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c

index d34ed042f6..1766163b33 100644

--- a/src/core/dbus-manager.c

+++ b/src/core/dbus-manager.c

@@ -1064,7 +1064,7 @@ static int method_unsubscribe(sd_bus *bus, sd_bus_message *message, void *userda

         return sd_bus_reply_method_return(message, NULL);

 }

-static int method_dump(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {

+static int dump_impl(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error, int (*reply)(sd_bus_message *, char *)) {

         _cleanup_free_ char *dump = NULL;

         _cleanup_fclose_ FILE *f = NULL;

         Manager *m = userdata;

@@ -1089,13 +1089,34 @@ static int method_dump(sd_bus *bus, sd_bus_message *message, void *userdata, sd_

         manager_dump_jobs(m, f, NULL);

         fflush(f);

-

         if (ferror(f))

                 return -ENOMEM;

+        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 *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {

+        return dump_impl(bus, 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 *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {

+        return dump_impl(bus, message, userdata, error, reply_dump_by_fd);

+}

+

 static int method_create_snapshot(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {

         _cleanup_free_ char *path = NULL;

         Manager *m = userdata;

@@ -2092,6 +2113,7 @@ 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_create_snapshot, 0),

         SD_BUS_METHOD("RemoveSnapshot", "s", NULL, method_remove_snapshot, 0),

         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 3997dd0b4e..8187cf1731 100644

--- a/src/core/org.freedesktop.systemd1.conf

+++ b/src/core/org.freedesktop.systemd1.conf

@@ -96,6 +96,10 @@

                        send_interface="org.freedesktop.systemd1.Manager"

                        send_member="Dump"/>

+                

+                       send_interface="org.freedesktop.systemd1.Manager"

+                       send_member="DumpByFileDescriptor"/>

+

                        send_interface="org.freedesktop.systemd1.Manager"

                        send_member="GetDefaultTarget"/>