From 613a02b7d67864af1860e9137e2ee101d603463e Mon Sep 17 00:00:00 2001

From: Jan Synacek <jsynacek@redhat.com>

Date: Thu, 25 Apr 2019 12:19:16 +0200

Subject: [PATCH] debug-generator: enable custom systemd.debug_shell tty

(cherry picked from commit 93912e872fb14e9c372e090409e429084a6450f5)

Resolves: #1723722

---

 man/custom-entities.ent.in            |  1 +

 man/systemd-debug-generator.xml       | 13 ++++++---

 meson.build                           |  1 +

 src/debug-generator/debug-generator.c | 41 +++++++++++++++++++++------

 4 files changed, 43 insertions(+), 13 deletions(-)

diff --git a/man/custom-entities.ent.in b/man/custom-entities.ent.in

index e2bd44e5e7..85805777a0 100644

--- a/man/custom-entities.ent.in

+++ b/man/custom-entities.ent.in

@@ -8,3 +8,4 @@

+

diff --git a/man/systemd-debug-generator.xml b/man/systemd-debug-generator.xml

index fa88e8ac01..25d8b1a873 100644

--- a/man/systemd-debug-generator.xml

+++ b/man/systemd-debug-generator.xml

@@ -1,6 +1,10 @@

-

+

+  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [

+

+%entities;

+]>

   SPDX-License-Identifier: LGPL-2.1+

 -->

@@ -57,9 +61,10 @@

     <option>rd.systemd.debug_shell</option> option is

     specified, the debug shell service

     <literal>debug-shell.service</literal> is pulled into the boot

-    transaction. It will spawn a debug shell on tty9 during early

-    system startup. Note that the shell may also be turned on

-    persistently by enabling it with

+    transaction and a debug shell will be spawned during early boot.

+    By default, <filename>&DEBUGTTY;</filename> is used, but a specific tty can also be set,

+    either with or without the <filename>/dev/</filename> prefix.

+    Note that the shell may also be turned on persistently by enabling it with

     <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s

     <command>enable</command> command.

     <option>rd.systemd.debug_shell=</option> is honored only by initial

diff --git a/meson.build b/meson.build

index fe82ca4ac2..70811c29cf 100644

--- a/meson.build

+++ b/meson.build

@@ -768,6 +768,7 @@ conf.set_quoted('GETTEXT_PACKAGE', meson.project_name())

 substs.set('SUSHELL', get_option('debug-shell'))

 substs.set('DEBUGTTY', get_option('debug-tty'))

+conf.set_quoted('DEBUGTTY', get_option('debug-tty'))

 enable_debug_hashmap = false

 enable_debug_mmap_cache = false

diff --git a/src/debug-generator/debug-generator.c b/src/debug-generator/debug-generator.c

index 800d31cebe..ddef385833 100644

--- a/src/debug-generator/debug-generator.c

+++ b/src/debug-generator/debug-generator.c

@@ -1,8 +1,11 @@

 /* SPDX-License-Identifier: LGPL-2.1+ */

 #include "alloc-util.h"

+#include "dropin.h"

+#include "generator.h"

 #include "mkdir.h"

 #include "parse-util.h"

+#include "path-util.h"

 #include "proc-cmdline.h"

 #include "special.h"

 #include "string-util.h"

@@ -14,7 +17,7 @@ static char *arg_default_unit = NULL;

 static const char *arg_dest = "/tmp";

 static char **arg_mask = NULL;

 static char **arg_wants = NULL;

-static bool arg_debug_shell = false;

+static char *arg_debug_shell = NULL;

 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {

         int r;

@@ -50,15 +53,16 @@ static int parse_proc_cmdline_item(const char *key, const char *value, void *dat

                         return log_oom();

         } else if (proc_cmdline_key_streq(key, "systemd.debug_shell")) {

+                const char *t = NULL;

-                if (value) {

-                        r = parse_boolean(value);

-                        if (r < 0)

-                                log_error("Failed to parse systemd.debug_shell= argument '%s', ignoring.", value);

-                        else

-                                arg_debug_shell = r;

-                } else

-                        arg_debug_shell = true;

+                r = value ? parse_boolean(value) : 1;

+                if (r < 0)

+                        t = skip_dev_prefix(value);

+                else if (r > 0)

+                        t = skip_dev_prefix(DEBUGTTY);

+

+                if (free_and_strdup(&arg_debug_shell, t) < 0)

+                        return log_oom();

         } else if (streq(key, "systemd.unit")) {

@@ -136,6 +140,23 @@ static int generate_wants_symlinks(void) {

         return r;

 }

+static void install_debug_shell_dropin(const char *dir) {

+        int r;

+

+        if (streq(arg_debug_shell, skip_dev_prefix(DEBUGTTY)))

+                return;

+

+        r = write_drop_in_format(dir, "debug-shell.service", 50, "tty",

+                        "[Unit]\n"

+                        "Description=Early root shell on /dev/%s FOR DEBUGGING ONLY\n"

+                        "ConditionPathExists=\n"

+                        "[Service]\n"

+                        "TTYPath=/dev/%s",

+                        arg_debug_shell, arg_debug_shell);

+        if (r < 0)

+                log_warning_errno(r, "Failed to write drop-in for debug-shell.service, ignoring: %m");

+}

+

 int main(int argc, char *argv[]) {

         int r, q;

@@ -164,6 +185,8 @@ int main(int argc, char *argv[]) {

                         r = log_oom();

                         goto finish;

                 }

+

+                install_debug_shell_dropin(arg_dest);

         }

         r = generate_mask_symlinks();