journal/cat: allow connecting output to specific journal namespace

[thirdparty/systemd.git] / src / journal / cat.c

diff --git a/src/journal/cat.c b/src/journal/cat.c
index 0c2c0d6152d113de3c5d53d1e63f5396e47bf481..1634f30b44e1958940ed364f31384ba354624397 100644 (file)
--- a/src/journal/cat.c
+++ b/src/journal/cat.c
@@ -5,12 +5,16 @@
 #include <getopt.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 #include "sd-journal.h"
 
 #include "alloc-util.h"
+#include "build.h"
+#include "env-util.h"
 #include "fd-util.h"
+#include "format-util.h"
 #include "main-func.h"
 #include "parse-argument.h"
 #include "parse-util.h"
@@ -18,9 +22,9 @@
 #include "string-util.h"
 #include "syslog-util.h"
 #include "terminal-util.h"
-#include "util.h"
 
 static const char *arg_identifier = NULL;
+static const char *arg_namespace = NULL;
 static int arg_priority = LOG_INFO;
 static int arg_stderr_priority = -1;
 static bool arg_level_prefix = true;
@@ -41,6 +45,7 @@ static int help(void) {
                "  -p --priority=PRIORITY         Set priority value (0..7)\n"
                "     --stderr-priority=PRIORITY  Set priority value (0..7) used for stderr\n"
                "     --level-prefix=BOOL         Control whether level prefix shall be parsed\n"
+               "     --namespace=NAMESPACE       Connect to specified journal namespace\n"
                "\nSee the %s for details.\n",
                program_invocation_short_name,
                ansi_highlight(),
@@ -55,7 +60,8 @@ static int parse_argv(int argc, char *argv[]) {
         enum {
                 ARG_VERSION = 0x100,
                 ARG_STDERR_PRIORITY,
-                ARG_LEVEL_PREFIX
+                ARG_LEVEL_PREFIX,
+                ARG_NAMESPACE,
         };
 
         static const struct option options[] = {
@@ -65,6 +71,7 @@ static int parse_argv(int argc, char *argv[]) {
                 { "priority",        required_argument, NULL, 'p'                 },
                 { "stderr-priority", required_argument, NULL, ARG_STDERR_PRIORITY },
                 { "level-prefix",    required_argument, NULL, ARG_LEVEL_PREFIX    },
+                { "namespace",       required_argument, NULL, ARG_NAMESPACE       },
                 {}
         };
 
@@ -73,6 +80,9 @@ static int parse_argv(int argc, char *argv[]) {
         assert(argc >= 0);
         assert(argv);
 
+        /* Resetting to 0 forces the invocation of an internal initialization routine of getopt_long()
+         * that checks for GNU extensions in optstring ('-' or '+' at the beginning). */
+        optind = 0;
         while ((c = getopt_long(argc, argv, "+ht:p:", options, NULL)) >= 0)
 
                 switch (c) {
@@ -111,6 +121,13 @@ static int parse_argv(int argc, char *argv[]) {
                                 return r;
                         break;
 
+                case ARG_NAMESPACE:
+                        if (isempty(optarg))
+                                arg_namespace = NULL;
+                        else
+                                arg_namespace = optarg;
+                        break;
+
                 case '?':
                         return -EINVAL;
 
@@ -122,7 +139,7 @@ static int parse_argv(int argc, char *argv[]) {
 }
 
 static int run(int argc, char *argv[]) {
-        _cleanup_close_ int outfd = -1, errfd = -1, saved_stderr = -1;
+        _cleanup_close_ int outfd = -EBADF, errfd = -EBADF, saved_stderr = -EBADF;
         int r;
 
         log_setup();
@@ -131,12 +148,12 @@ static int run(int argc, char *argv[]) {
         if (r <= 0)
                 return r;
 
-        outfd = sd_journal_stream_fd(arg_identifier, arg_priority, arg_level_prefix);
+        outfd = sd_journal_stream_fd_with_namespace(arg_namespace, arg_identifier, arg_priority, arg_level_prefix);
         if (outfd < 0)
                 return log_error_errno(outfd, "Failed to create stream fd: %m");
 
         if (arg_stderr_priority >= 0 && arg_stderr_priority != arg_priority) {
-                errfd = sd_journal_stream_fd(arg_identifier, arg_stderr_priority, arg_level_prefix);
+                errfd = sd_journal_stream_fd_with_namespace(arg_namespace, arg_identifier, arg_stderr_priority, arg_level_prefix);
                 if (errfd < 0)
                         return log_error_errno(errfd, "Failed to create stream fd: %m");
         }
@@ -151,8 +168,20 @@ static int run(int argc, char *argv[]) {
 
         if (argc <= optind)
                 (void) execl("/bin/cat", "/bin/cat", NULL);
-        else
+        else {
+                struct stat st;
+
+                if (fstat(STDERR_FILENO, &st) < 0)
+                        return log_error_errno(errno,
+                                               "Failed to fstat(%s): %m",
+                                               FORMAT_PROC_FD_PATH(STDERR_FILENO));
+
+                r = setenvf("JOURNAL_STREAM", /* overwrite = */ true, DEV_FMT ":" INO_FMT, (dev_t) st.st_dev, st.st_ino);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to set environment variable JOURNAL_STREAM: %m");
+
                 (void) execvp(argv[optind], argv + optind);
+        }
         r = -errno;
 
         /* Let's try to restore a working stderr, so we can print the error message */