Merge "Basic PoC for DLog stdout redirector" into tizensubmit/tizen/20210326.090524submit/tizen/20210324.095642accepted/tizen/unified/20210328.230635

5 files changed, 62 insertions, 2 deletions

diff --git a/meson.build b/meson.build
index 06002d656c..98d333b684 100644
--- a/meson.build
+++ b/meson.build
@@ -859,6 +859,8 @@ if not libcap.found()
         libcap = cc.find_library('cap')
 endif
 
+libdlog_redirect_stdout = dependency('dlog-redirect-stdout', required : true)
+
 libmount = dependency('mount',
                       version : fuzzer_build ? '>= 0' : '>= 2.30')
 
diff --git a/packaging/systemd.spec b/packaging/systemd.spec
index a1aa48b993..03feb750eb 100644
--- a/packaging/systemd.spec
+++ b/packaging/systemd.spec
@@ -84,6 +84,7 @@ BuildRequires:  pkgconfig(liblzma)
 BuildRequires:  pkgconfig(libkmod)
 BuildRequires:  pkgconfig(mount)
 BuildRequires:  pkgconfig(libdbuspolicy1)
+BuildRequires:  pkgconfig(dlog-redirect-stdout)
 BuildRequires:  meson
 BuildRequires:  acl
 BuildRequires:  python
diff --git a/src/core/execute.c b/src/core/execute.c
index 414c3854b8..14a7d1399b 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -14,6 +14,8 @@
 #include <unistd.h>
 #include <utmpx.h>
 
+#include <dlog/dlog-redirect-stdout.h>
+
 #if HAVE_PAM
 #include <security/pam_appl.h>
 #endif
@@ -253,18 +255,26 @@ static bool exec_context_needs_term(const ExecContext *c) {
         return !!c->tty_path;
 }
 
-static int open_null_as(int flags, int nfd) {
+static int open_device_as(const char *devname, int flags, int nfd) {
         int fd;
 
         assert(nfd >= 0);
 
-        fd = open("/dev/null", flags|O_NOCTTY);
+        fd = open(devname, flags|O_NOCTTY);
         if (fd < 0)
                 return -errno;
 
         return move_fd(fd, nfd, false);
 }
 
+static int open_null_as(int flags, int nfd) {
+        return open_device_as("/dev/null", flags, nfd);
+}
+
+static int open_kmsg_as(int flags, int nfd) {
+        return open_device_as("/dev/kmsg", flags, nfd);
+}
+
 static int connect_journal_socket(int fd, uid_t uid, gid_t gid) {
         static const union sockaddr_union sa = {
                 .un.sun_family = AF_UNIX,
@@ -560,6 +570,28 @@ static bool can_inherit_stderr_from_stdout(
         return true;
 }
 
+static int wire_up_dlog(int fileno, const char *ident)
+{
+        /* NB: dlogutil has FOO* tag filtering wildcards but not *FOO
+         * therefore the STDFOO part of the final tag goes in front.
+         *
+         * The tag can nominally be longer than 128 but dlogutil will
+         * not print a longer one anyway and it's good to limit overhead */
+        char tag[128];
+        int priority;
+
+        if (fileno == STDERR_FILENO) {
+                priority = 6; // ERROR
+                snprintf(tag, sizeof tag, "STDERR_%s", ident);
+        } else {
+                priority = 4; // INFO
+                snprintf(tag, sizeof tag, "STDOUT_%s", ident);
+        }
+
+        return connect_dlog(2, // SYSTEM dlog buffer (consider also 0 for generic MAIN buffer)
+                fileno, tag, priority);
+}
+
 static int setup_output(
                 const Unit *unit,
                 const ExecContext *context,
@@ -680,6 +712,24 @@ static int setup_output(
                 }
                 return r;
 
+        case EXEC_OUTPUT_DLOG:
+                r = wire_up_dlog(fileno, ident);
+                return r < 0 ? r : fileno;
+
+        case EXEC_OUTPUT_DLOG_OR_NULL:
+                r = wire_up_dlog(fileno, ident);
+                if (r >= 0)
+                        return fileno;
+                else
+                        return open_null_as(O_WRONLY, fileno);
+
+        case EXEC_OUTPUT_DLOG_OR_KMSG:
+                r = wire_up_dlog(fileno, ident);
+                if (r >= 0)
+                        return fileno;
+                else
+                        return open_kmsg_as(O_WRONLY, fileno);
+
         case EXEC_OUTPUT_SOCKET:
                 assert(socket_fd >= 0);
 
@@ -5627,6 +5677,9 @@ static const char* const exec_output_table[_EXEC_OUTPUT_MAX] = {
         [EXEC_OUTPUT_NAMED_FD] = "fd",
         [EXEC_OUTPUT_FILE] = "file",
         [EXEC_OUTPUT_FILE_APPEND] = "append",
+        [EXEC_OUTPUT_DLOG] = "dlog",
+        [EXEC_OUTPUT_DLOG_OR_NULL] = "dlog|null",
+        [EXEC_OUTPUT_DLOG_OR_KMSG] = "dlog|kmsg",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(exec_output, ExecOutput);
diff --git a/src/core/execute.h b/src/core/execute.h
index 43ec07c143..11a4054712 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -60,6 +60,9 @@ typedef enum ExecOutput {
         EXEC_OUTPUT_NAMED_FD,
         EXEC_OUTPUT_FILE,
         EXEC_OUTPUT_FILE_APPEND,
+        EXEC_OUTPUT_DLOG,
+        EXEC_OUTPUT_DLOG_OR_NULL,
+        EXEC_OUTPUT_DLOG_OR_KMSG,
         _EXEC_OUTPUT_MAX,
         _EXEC_OUTPUT_INVALID = -1
 } ExecOutput;
diff --git a/src/core/meson.build b/src/core/meson.build
index 9cd72f5ea0..a7afe19507 100644
--- a/src/core/meson.build
+++ b/src/core/meson.build
@@ -181,6 +181,7 @@ libcore = static_library(
                         libkmod,
                         libapparmor,
                         libselinux,
+                        libdlog_redirect_stdout,
                         libmount])
 
 systemd_sources = files('main.c')