Merge branch 'wip/smcv/gio-launch-desktop-sd-journal' into 'main'

Bring back gio-launch-desktop, use it to redirect stdout/stderr to the Journal

Closes #2682

See merge request GNOME/glib!2819

9 files changed, 413 insertions, 52 deletions

diff --git a/gio/gdesktopappinfo.c b/gio/gdesktopappinfo.c
index c0950ae75..c46a8f09b 100644
--- a/gio/gdesktopappinfo.c
+++ b/gio/gdesktopappinfo.c
@@ -51,6 +51,7 @@
 #include "gfileicon.h"
 #include <glib/gstdio.h>
 #include "glibintl.h"
+#include "glib-private.h"
 #include "giomodule-priv.h"
 #include "gappinfo.h"
 #include "gappinfoprivate.h"
@@ -165,6 +166,7 @@ static const gchar    *desktop_file_dirs_config_dir = NULL;
 static DesktopFileDir *desktop_file_dir_user_config = NULL;  /* (owned) */
 static DesktopFileDir *desktop_file_dir_user_data = NULL;  /* (owned) */
 static GMutex          desktop_file_dir_lock;
+static const gchar    *gio_launch_desktop_path = NULL;
 
 /* Monitor 'changed' signal handler {{{2 */
 static void desktop_file_dir_reset (DesktopFileDir *dir);
@@ -2872,15 +2874,6 @@ g_desktop_app_info_launch_uris_with_spawn (GDesktopAppInfo            *info,
       char *sn_id = NULL;
       char **wrapped_argv;
       int i;
-      gsize j;
-      const gchar * const wrapper_argv[] =
-        {
-          "/bin/sh",
-          "-e",
-          "-u",
-          "-c", "export GIO_LAUNCHED_DESKTOP_FILE_PID=$$; exec \"$@\"",
-          "sh",  /* argv[0] for sh */
-        };
 
       old_uris = dup_uris;
       if (!expand_application_parameters (info, exec_line, &dup_uris, &argc, &argv, error))
@@ -2924,26 +2917,32 @@ g_desktop_app_info_launch_uris_with_spawn (GDesktopAppInfo            *info,
           emit_launch_started (launch_context, info, sn_id);
         }
 
-      /* Wrap the @argv in a command which will set the
-       * `GIO_LAUNCHED_DESKTOP_FILE_PID` environment variable. We can’t set this
-       * in @envp along with `GIO_LAUNCHED_DESKTOP_FILE` because we need to know
-       * the PID of the new forked process. We can’t use setenv() between fork()
-       * and exec() because we’d rather use posix_spawn() for speed.
-       *
-       * `sh` should be available on all the platforms that `GDesktopAppInfo`
-       * currently supports (since they are all POSIX). If additional platforms
-       * need to be supported in future, it will probably have to be replaced
-       * with a wrapper program (grep the GLib git history for
-       * `gio-launch-desktop` for an example of this which could be
-       * resurrected). */
-      wrapped_argv = g_new (char *, argc + G_N_ELEMENTS (wrapper_argv) + 1);
-
-      for (j = 0; j < G_N_ELEMENTS (wrapper_argv); j++)
-        wrapped_argv[j] = g_strdup (wrapper_argv[j]);
+      if (g_once_init_enter (&gio_launch_desktop_path))
+        {
+          const gchar *tmp = NULL;
+          gboolean is_setuid = GLIB_PRIVATE_CALL (g_check_setuid) ();
+
+          /* Allow test suite to specify path to gio-launch-desktop */
+          if (!is_setuid)
+            tmp = g_getenv ("GIO_LAUNCH_DESKTOP");
+
+          /* Allow build system to specify path to gio-launch-desktop */
+          if (tmp == NULL && g_file_test (GIO_LAUNCH_DESKTOP, G_FILE_TEST_IS_EXECUTABLE))
+            tmp = GIO_LAUNCH_DESKTOP;
+
+          /* Fall back on usual searching in $PATH */
+          if (tmp == NULL)
+            tmp = "gio-launch-desktop";
+          g_once_init_leave (&gio_launch_desktop_path, tmp);
+        }
+
+      wrapped_argv = g_new (char *, argc + 2);
+      wrapped_argv[0] = g_strdup (gio_launch_desktop_path);
+
       for (i = 0; i < argc; i++)
-        wrapped_argv[i + G_N_ELEMENTS (wrapper_argv)] = g_steal_pointer (&argv[i]);
+        wrapped_argv[i + 1] = g_steal_pointer (&argv[i]);
 
-      wrapped_argv[i + G_N_ELEMENTS (wrapper_argv)] = NULL;
+      wrapped_argv[i + 1] = NULL;
       g_free (argv);
       argv = NULL;
 
diff --git a/gio/gio-launch-desktop.c b/gio/gio-launch-desktop.c
new file mode 100644
index 000000000..9ed6712f7
--- /dev/null
+++ b/gio/gio-launch-desktop.c
@@ -0,0 +1,253 @@
+/* GIO - GLib Input, Output and Streaming Library
+ *
+ * Copyright 2004 Ximian Inc.
+ * Copyright 2011-2022 systemd contributors
+ * Copyright (C) 2018 Endless Mobile, Inc.
+ * Copyright 2022 Collabora Ltd.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Daniel Drake <drake@endlessm.com>
+ */
+
+/*
+ * gio-launch-desktop: GDesktopAppInfo helper
+ * Executable wrapper to set GIO_LAUNCHED_DESKTOP_FILE_PID
+ * There are complications when doing this in a fork()/exec() codepath,
+ * and it cannot otherwise be done with posix_spawn().
+ * This wrapper is designed to be minimal and lightweight.
+ * It does not even link against glib.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#if defined(__linux__) && !defined(__BIONIC__)
+#include <alloca.h>
+#include <assert.h>
+#include <errno.h>
+#include <stddef.h>
+#include <string.h>
+#include <syslog.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include "gjournal-private.h"
+
+/*
+ * write_all:
+ * @fd: a file descriptor
+ * @vbuf: a buffer
+ * @to_write: length of @vbuf
+ *
+ * Write all bytes from @vbuf to @fd, blocking if necessary.
+ *
+ * Returns: 0 on success, -1 with errno set on failure
+ */
+static int
+write_all (int fd, const void *vbuf, size_t to_write)
+{
+  const char *buf = vbuf;
+
+  while (to_write > 0)
+    {
+      ssize_t count = write (fd, buf, to_write);
+      if (count < 0)
+        {
+          if (errno != EINTR)
+            return -1;
+        }
+      else
+        {
+          to_write -= count;
+          buf += count;
+        }
+    }
+
+  return 0;
+}
+
+/*
+ * journal_stream_fd:
+ * @identifier: identifier (syslog tag) for logged messages
+ * @priority: a priority between `LOG_EMERG` and `LOG_DEBUG` inclusive
+ * @level_prefix: if nonzero, journald will interpret prefixes like <0>
+ *  as specifying the priority for a line
+ *
+ * Reimplementation of sd_journal_stream_fd(), to avoid having to link
+ * gio-launch-desktop to libsystemd.
+ *
+ * Note that unlike the libsystemd version, this reports errors by returning
+ * -1 with errno set.
+ *
+ * Returns: a non-negative fd number, or -1 with errno set on error
+ */
+static int
+journal_stream_fd (const char *identifier,
+                   int priority,
+                   int level_prefix)
+{
+  union
+  {
+    struct sockaddr sa;
+    struct sockaddr_un un;
+  } sa =
+  {
+    .un.sun_family = AF_UNIX,
+    .un.sun_path = "/run/systemd/journal/stdout",
+  };
+  socklen_t salen;
+  char *header;
+  int fd;
+  size_t l;
+  int saved_errno;
+  /* Arbitrary large size for the sending buffer, from systemd */
+  int large_buffer_size = 8 * 1024 * 1024;
+
+  static_assert (LOG_EMERG == 0, "Linux ABI defines LOG_EMERG");
+  static_assert (LOG_DEBUG == 7, "Linux ABI defines LOG_DEBUG");
+
+  fd = socket (AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
+
+  if (fd < 0)
+    goto fail;
+
+  salen = offsetof (struct sockaddr_un, sun_path) + strlen (sa.un.sun_path) + 1;
+
+  if (connect (fd, &sa.sa, salen) < 0)
+    goto fail;
+
+  if (shutdown (fd, SHUT_RD) < 0)
+    goto fail;
+
+  (void) setsockopt (fd, SOL_SOCKET, SO_SNDBUF, &large_buffer_size,
+                     (socklen_t) sizeof (large_buffer_size));
+
+  if (identifier == NULL)
+    identifier = "";
+
+  if (priority < 0)
+    priority = 0;
+
+  if (priority > 7)
+    priority = 7;
+
+  l = strlen (identifier);
+  header = alloca (l + 1  /* identifier, newline */
+                   + 1    /* empty unit ID, newline */
+                   + 2    /* priority, newline */
+                   + 2    /* level prefix, newline */
+                   + 2    /* don't forward to syslog */
+                   + 2    /* don't forward to kmsg */
+                   + 2    /* don't forward to console */);
+  memcpy (header, identifier, l);
+  header[l++] = '\n';
+  header[l++] = '\n';   /* empty unit ID */
+  header[l++] = '0' + priority;
+  header[l++] = '\n';
+  header[l++] = '0' + !!level_prefix;
+  header[l++] = '\n';
+  header[l++] = '0';    /* don't forward to syslog */
+  header[l++] = '\n';
+  header[l++] = '0';    /* don't forward to kmsg */
+  header[l++] = '\n';
+  header[l++] = '0';    /* don't forward to console */
+  header[l++] = '\n';
+
+  if (write_all (fd, header, l) < 0)
+    goto fail;
+
+  return fd;
+
+fail:
+  saved_errno = errno;
+
+  if (fd >= 0)
+    close (fd);
+
+  errno = saved_errno;
+  return -1;
+}
+
+static void
+set_up_journal (const char *argv1)
+{
+  const char *identifier;
+  const char *slash;
+  int fd;
+
+  if (!_g_fd_is_journal (STDOUT_FILENO) && !_g_fd_is_journal (STDERR_FILENO))
+    return;
+
+  identifier = getenv ("GIO_LAUNCHED_DESKTOP_FILE");
+
+  if (identifier == NULL)
+    identifier = argv1;
+
+  slash = strrchr (identifier, '/');
+
+  if (slash != NULL && slash[1] != '\0')
+    identifier = slash + 1;
+
+  fd = journal_stream_fd (identifier, LOG_INFO, 0);
+
+  /* Silently ignore failure to open the Journal */
+  if (fd < 0)
+    return;
+
+  if (dup2 (fd, STDOUT_FILENO) != STDOUT_FILENO)
+    fprintf (stderr,
+             "gio-launch-desktop[%d]: Unable to redirect \"%s\" to Journal: %s",
+             getpid (),
+             identifier,
+             strerror (errno));
+
+  if (dup2 (fd, STDERR_FILENO) != STDERR_FILENO)
+    fprintf (stderr,
+             "gio-launch-desktop[%d]: Unable to redirect \"%s\" to Journal: %s",
+             getpid (),
+             identifier,
+             strerror (errno));
+
+  close (fd);
+}
+
+#endif
+
+int
+main (int argc, char *argv[])
+{
+  pid_t pid = getpid ();
+  char buf[50];
+  int r;
+
+  if (argc < 2)
+    return -1;
+
+  r = snprintf (buf, sizeof (buf), "GIO_LAUNCHED_DESKTOP_FILE_PID=%ld", (long) pid);
+  if (r < 0 || (size_t) r >= sizeof (buf))
+    return -1;
+
+  putenv (buf);
+
+#if defined(__linux__) && !defined(__BIONIC__)
+  set_up_journal (argv[1]);
+#endif
+
+  return execvp (argv[1], argv + 1);
+}
diff --git a/gio/meson.build b/gio/meson.build
index e64135419..69bb0603e 100644
--- a/gio/meson.build
+++ b/gio/meson.build
@@ -1,6 +1,7 @@
 gio_c_args = [
   '-DG_LOG_DOMAIN="GLib-GIO"',
   '-DGIO_COMPILATION',
+  '-DGIO_LAUNCH_DESKTOP="@0@"'.format(glib_prefix / multiarch_libexecdir / 'gio-launch-desktop'),
   '-DGIO_MODULE_DIR="@0@"'.format(glib_giomodulesdir),
   '-DLOCALSTATEDIR="@0@"'.format(glib_localstatedir),
 ]
@@ -399,6 +400,19 @@ if host_system != 'windows'
     contenttype_sources += files('gcontenttype.c')
     appinfo_sources += files('gdesktopappinfo.c')
     gio_unix_include_headers += files('gdesktopappinfo.h')
+    launch_desktop_sources = files('gio-launch-desktop.c')
+
+    if host_system == 'linux'
+      launch_desktop_sources += files('../glib/gjournal-private.c')
+    endif
+
+    gio_launch_desktop = executable('gio-launch-desktop', launch_desktop_sources,
+      include_directories : glibinc,
+      install : true,
+      install_dir : multiarch_libexecdir,
+      c_args : gio_c_args,
+      # intl.lib is not compatible with SAFESEH
+      link_args : noseh_link_args)
   endif
 
   subdir('xdgmime')
diff --git a/gio/tests/meson.build b/gio/tests/meson.build
index 282b911c7..c3e4e4cb3 100644
--- a/gio/tests/meson.build
+++ b/gio/tests/meson.build
@@ -149,6 +149,10 @@ test_env.set('G_TEST_SRCDIR', meson.current_source_dir())
 test_env.set('G_TEST_BUILDDIR', meson.current_build_dir())
 test_env.set('GIO_MODULE_DIR', '')
 
+if host_system != 'windows' and not glib_have_cocoa
+  test_env.set('GIO_LAUNCH_DESKTOP', gio_launch_desktop.full_path())
+endif
+
 # Check for libdbus1 - Optional - is only used in the GDBus test cases
 # 1.2.14 required for dbus_message_set_serial
 dbus1_dep = dependency('dbus-1', required : false, version : '>= 1.2.14')
diff --git a/glib/gjournal-private.c b/glib/gjournal-private.c
new file mode 100644
index 000000000..f45e2cf1c
--- /dev/null
+++ b/glib/gjournal-private.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2016 Red Hat, Inc.
+ * Copyright 2016-2022 Collabora Ltd.
+ * Copyright 2017-2022 Endless OS Foundation, LLC
+ * Copyright 2018 Will Thompson
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "gjournal-private.h"
+
+#if defined(__linux__) && !defined(__BIONIC__)
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+/*
+ * Reimplementation of g_str_has_prefix(), necessary when compiled into
+ * gio-launch-desktop.
+ */
+static int
+str_has_prefix (const char *str,
+                const char *prefix)
+{
+  return strncmp (str, prefix, strlen (prefix)) == 0;
+}
+
+/*
+ * _g_fd_is_journal:
+ * @output_fd: output file descriptor to check
+ *
+ * Same as g_log_writer_is_journald(), but with no GLib dependencies.
+ *
+ * Returns: 1 if @output_fd points to the journal, 0 otherwise
+ */
+int
+_g_fd_is_journal (int output_fd)
+{
+  /* FIXME: Use the new journal API for detecting whether we’re writing to the
+   * journal. See: https://github.com/systemd/systemd/issues/2473
+   */
+  union {
+    struct sockaddr_storage storage;
+    struct sockaddr sa;
+    struct sockaddr_un un;
+  } addr;
+  socklen_t addr_len;
+  int err;
+
+  if (output_fd < 0)
+    return 0;
+
+  /* Namespaced journals start with `/run/systemd/journal.${name}/` (see
+   * `RuntimeDirectory=systemd/journal.%i` in `systemd-journald@.service`. The
+   * default journal starts with `/run/systemd/journal/`. */
+  memset (&addr, 0, sizeof (addr));
+  addr_len = sizeof(addr);
+  err = getpeername (output_fd, &addr.sa, &addr_len);
+  if (err == 0 && addr.storage.ss_family == AF_UNIX)
+    return (str_has_prefix (addr.un.sun_path, "/run/systemd/journal/") ||
+            str_has_prefix (addr.un.sun_path, "/run/systemd/journal."));
+
+  return 0;
+}
+#endif
diff --git a/glib/gjournal-private.h b/glib/gjournal-private.h
new file mode 100644
index 000000000..46e0e5a85
--- /dev/null
+++ b/glib/gjournal-private.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2016-2022 Collabora Ltd.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __GLIB_JOURNAL_PRIVATE_H__
+#define __GLIB_JOURNAL_PRIVATE_H__
+
+int _g_fd_is_journal (int output_fd);
+
+#endif
diff --git a/glib/gmessages.c b/glib/gmessages.c
index 97c5b31b1..bbea25375 100644
--- a/glib/gmessages.c
+++ b/glib/gmessages.c
@@ -202,6 +202,10 @@
 #include "gpattern.h"
 #include "gthreadprivate.h"
 
+#if defined(__linux__) && !defined(__BIONIC__)
+#include "gjournal-private.h"
+#endif
+
 #ifdef G_OS_UNIX
 #include <unistd.h>
 #endif
@@ -2223,32 +2227,10 @@ gboolean
 g_log_writer_is_journald (gint output_fd)
 {
 #if defined(__linux__) && !defined(__BIONIC__)
-  /* FIXME: Use the new journal API for detecting whether we’re writing to the
-   * journal. See: https://github.com/systemd/systemd/issues/2473
-   */
-  union {
-    struct sockaddr_storage storage;
-    struct sockaddr sa;
-    struct sockaddr_un un;
-  } addr;
-  socklen_t addr_len;
-  int err;
-
-  if (output_fd < 0)
-    return FALSE;
-
-  /* Namespaced journals start with `/run/systemd/journal.${name}/` (see
-   * `RuntimeDirectory=systemd/journal.%i` in `systemd-journald@.service`. The
-   * default journal starts with `/run/systemd/journal/`. */
-  memset (&addr, 0, sizeof (addr));
-  addr_len = sizeof(addr);
-  err = getpeername (output_fd, &addr.sa, &addr_len);
-  if (err == 0 && addr.storage.ss_family == AF_UNIX)
-    return (g_str_has_prefix (addr.un.sun_path, "/run/systemd/journal/") ||
-            g_str_has_prefix (addr.un.sun_path, "/run/systemd/journal."));
-#endif
-
+  return _g_fd_is_journal (output_fd);
+#else
   return FALSE;
+#endif
 }
 
 static void escape_string (GString *string);
diff --git a/glib/meson.build b/glib/meson.build
index 6062c11a1..bcfcba94f 100644
--- a/glib/meson.build
+++ b/glib/meson.build
@@ -336,6 +336,10 @@ else
   platform_deps = []
 endif
 
+if host_system == 'linux'
+  glib_sources += files('gjournal-private.c')
+endif
+
 if glib_have_cocoa
   glib_sources += files('gosxutils.m')
   framework_dep = dependency('appleframeworks', modules : ['Foundation', 'CoreFoundation', 'AppKit'])
diff --git a/meson.build b/meson.build
index 3f28a71ee..1d1122627 100644
--- a/meson.build
+++ b/meson.build
@@ -88,11 +88,13 @@ if get_option('multiarch')
   # to an architecture-dependent location, with a compatibility symlink
   # in the PATH.
   multiarch_bindir = get_option('libdir') / 'glib-2.0'
+  multiarch_libexecdir = multiarch_bindir
   pkgconfig_multiarch_bindir = '${libdir}/glib-2.0'
 else
   # For single-architecture distributions, just install them into the PATH
   # as was traditionally done.
   multiarch_bindir = get_option('bindir')
+  multiarch_libexecdir = get_option('libexecdir')
   pkgconfig_multiarch_bindir = '${bindir}'
 endif