diff options
| -rw-r--r-- | configure.ac | 1 | ||||
| -rw-r--r-- | man/systemd.exec.xml | 20 | ||||
| -rw-r--r-- | src/basic/formats-util.h | 16 | ||||
| -rw-r--r-- | src/core/execute.c | 50 |
4 files changed, 80 insertions, 7 deletions
diff --git a/configure.ac b/configure.ac index ffc6eedcdd..7fd78bfb60 100644 --- a/configure.ac +++ b/configure.ac @@ -249,6 +249,7 @@ AC_CHECK_SIZEOF(uid_t) AC_CHECK_SIZEOF(gid_t) AC_CHECK_SIZEOF(time_t) AC_CHECK_SIZEOF(dev_t) +AC_CHECK_SIZEOF(ino_t) AC_CHECK_SIZEOF(rlim_t,,[ #include <sys/time.h> #include <sys/resource.h> diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml index a39e800854..dbfc7692f7 100644 --- a/man/systemd.exec.xml +++ b/man/systemd.exec.xml @@ -1539,6 +1539,26 @@ <citerefentry project='man-pages'><refentrytitle>termcap</refentrytitle><manvolnum>5</manvolnum></citerefentry>. </para></listitem> </varlistentry> + + <varlistentry> + <term><varname>$JOURNAL_STREAM</varname></term> + + <listitem><para>If the standard output or standard error output of the executed processes are connected to the + journal (for example, by setting <varname>StandardError=journal</varname>) <varname>$JOURNAL_STREAM</varname> + contains the device and inode numbers of the connection file descriptor, formatted in decimal, separated by a + colon (<literal>:</literal>). This permits invoked processes to safely detect whether their standard output or + standard error output are connected to the journal. The device and inode numbers of the file descriptors should + be compared with the values set in the environment variable to determine whether the process output is still + connected to the journal. Note that it is generally not sufficient to only check whether + <varname>$JOURNAL_STREAM</varname> is set at all as services might invoke external processes replacing their + standard output or standard error output, without unsetting the environment variable.</para> + + <para>This environment variable is primarily useful to allow services to optionally upgrade their used log + protocol to the native journal protocol (using + <citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry> and other + functions) if their standard output or standard error output is connected to the journal anyway, thus enabling + delivery of structured metadata along with logged messages.</para></listitem> + </varlistentry> </variablelist> <para>Additional variables may be configured by the following diff --git a/src/basic/formats-util.h b/src/basic/formats-util.h index 9b4e8e98fa..39a185f59b 100644 --- a/src/basic/formats-util.h +++ b/src/basic/formats-util.h @@ -61,3 +61,19 @@ #else # error Unknown rlim_t size #endif + +#if SIZEOF_DEV_T == 8 +# define DEV_FMT "%" PRIu64 +#elif SIZEOF_DEV_T == 4 +# define DEV_FMT "%" PRIu32 +#else +# error Unknown dev_t size +#endif + +#if SIZEOF_INO_T == 8 +# define INO_FMT "%" PRIu64 +#elif SIZEOF_INO_T == 4 +# define INO_FMT "%" PRIu32 +#else +# error Unknown ino_t size +#endif diff --git a/src/core/execute.c b/src/core/execute.c index b5a5997f15..3c3369373f 100644 --- a/src/core/execute.c +++ b/src/core/execute.c @@ -454,7 +454,10 @@ static int setup_output( int fileno, int socket_fd, const char *ident, - uid_t uid, gid_t gid) { + uid_t uid, + gid_t gid, + dev_t *journal_stream_dev, + ino_t *journal_stream_ino) { ExecOutput o; ExecInput i; @@ -464,6 +467,8 @@ static int setup_output( assert(context); assert(params); assert(ident); + assert(journal_stream_dev); + assert(journal_stream_ino); if (fileno == STDOUT_FILENO && params->stdout_fd >= 0) { @@ -543,6 +548,17 @@ static int setup_output( if (r < 0) { log_unit_error_errno(unit, r, "Failed to connect %s to the journal socket, ignoring: %m", fileno == STDOUT_FILENO ? "stdout" : "stderr"); r = open_null_as(O_WRONLY, fileno); + } else { + struct stat st; + + /* If we connected this fd to the journal via a stream, patch the device/inode into the passed + * parameters, but only then. This is useful so that we can set $JOURNAL_STREAM that permits + * services to detect whether they are connected to the journal or not. */ + + if (fstat(fileno, &st) >= 0) { + *journal_stream_dev = st.st_dev; + *journal_stream_ino = st.st_ino; + } } return r; @@ -1286,6 +1302,8 @@ static int build_environment( const char *home, const char *username, const char *shell, + dev_t journal_stream_dev, + ino_t journal_stream_ino, char ***ret) { _cleanup_strv_free_ char **our_env = NULL; @@ -1295,7 +1313,7 @@ static int build_environment( assert(c); assert(ret); - our_env = new0(char*, 11); + our_env = new0(char*, 12); if (!our_env) return -ENOMEM; @@ -1367,8 +1385,15 @@ static int build_environment( our_env[n_env++] = x; } + if (journal_stream_dev != 0 && journal_stream_ino != 0) { + if (asprintf(&x, "JOURNAL_STREAM=" DEV_FMT ":" INO_FMT, journal_stream_dev, journal_stream_ino) < 0) + return -ENOMEM; + + our_env[n_env++] = x; + } + our_env[n_env++] = NULL; - assert(n_env <= 11); + assert(n_env <= 12); *ret = our_env; our_env = NULL; @@ -1481,10 +1506,12 @@ static int exec_child( _cleanup_strv_free_ char **our_env = NULL, **pass_env = NULL, **accum_env = NULL, **final_argv = NULL; _cleanup_free_ char *mac_selinux_context_net = NULL; const char *username = NULL, *home = NULL, *shell = NULL, *wd; + dev_t journal_stream_dev = 0; + ino_t journal_stream_ino = 0; + bool needs_mount_namespace; uid_t uid = UID_INVALID; gid_t gid = GID_INVALID; int i, r; - bool needs_mount_namespace; assert(unit); assert(command); @@ -1584,13 +1611,13 @@ static int exec_child( return r; } - r = setup_output(unit, context, params, STDOUT_FILENO, socket_fd, basename(command->path), uid, gid); + r = setup_output(unit, context, params, STDOUT_FILENO, socket_fd, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino); if (r < 0) { *exit_status = EXIT_STDOUT; return r; } - r = setup_output(unit, context, params, STDERR_FILENO, socket_fd, basename(command->path), uid, gid); + r = setup_output(unit, context, params, STDERR_FILENO, socket_fd, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino); if (r < 0) { *exit_status = EXIT_STDERR; return r; @@ -1729,7 +1756,16 @@ static int exec_child( } } - r = build_environment(context, params, n_fds, home, username, shell, &our_env); + r = build_environment( + context, + params, + n_fds, + home, + username, + shell, + journal_stream_dev, + journal_stream_ino, + &our_env); if (r < 0) { *exit_status = EXIT_MEMORY; return r; |