1 files changed, 168 insertions, 0 deletions
diff --git a/src/journal/cat.c b/src/journal/cat.c
new file mode 100644
index 0000000..9900bd2
--- /dev/null
+++ b/src/journal/cat.c
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "sd-journal.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "main-func.h"
+#include "parse-util.h"
+#include "pretty-print.h"
+#include "string-util.h"
+#include "syslog-util.h"
+#include "util.h"
+
+static const char *arg_identifier = NULL;
+static int arg_priority = LOG_INFO;
+static int arg_stderr_priority = -1;
+static bool arg_level_prefix = true;
+
+static int help(void) {
+        _cleanup_free_ char *link = NULL;
+        int r;
+
+        r = terminal_urlify_man("systemd-cat", "1", &link);
+        if (r < 0)
+                return log_oom();
+
+        printf("%s [OPTIONS...] {COMMAND} ...\n\n"
+               "Execute process with stdout/stderr connected to the journal.\n\n"
+               "  -h --help                      Show this help\n"
+               "     --version                   Show package version\n"
+               "  -t --identifier=STRING         Set syslog identifier\n"
+               "  -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"
+               "\nSee the %s for details.\n"
+               , program_invocation_short_name
+               , link
+        );
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+
+        enum {
+                ARG_VERSION = 0x100,
+                ARG_STDERR_PRIORITY,
+                ARG_LEVEL_PREFIX
+        };
+
+        static const struct option options[] = {
+                { "help",            no_argument,       NULL, 'h'                 },
+                { "version",         no_argument,       NULL, ARG_VERSION         },
+                { "identifier",      required_argument, NULL, 't'                 },
+                { "priority",        required_argument, NULL, 'p'                 },
+                { "stderr-priority", required_argument, NULL, ARG_STDERR_PRIORITY },
+                { "level-prefix",    required_argument, NULL, ARG_LEVEL_PREFIX    },
+                {}
+        };
+
+        int c;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "+ht:p:", options, NULL)) >= 0)
+
+                switch (c) {
+
+                case 'h':
+                        help();
+                        return 0;
+
+                case ARG_VERSION:
+                        return version();
+
+                case 't':
+                        if (isempty(optarg))
+                                arg_identifier = NULL;
+                        else
+                                arg_identifier = optarg;
+                        break;
+
+                case 'p':
+                        arg_priority = log_level_from_string(optarg);
+                        if (arg_priority < 0)
+                                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                       "Failed to parse priority value.");
+                        break;
+
+                case ARG_STDERR_PRIORITY:
+                        arg_stderr_priority = log_level_from_string(optarg);
+                        if (arg_stderr_priority < 0)
+                                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                       "Failed to parse stderr priority value.");
+                        break;
+
+                case ARG_LEVEL_PREFIX: {
+                        int k;
+
+                        k = parse_boolean(optarg);
+                        if (k < 0)
+                                return log_error_errno(k, "Failed to parse level prefix value.");
+
+                        arg_level_prefix = k;
+                        break;
+                }
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached("Unhandled option");
+                }
+
+        return 1;
+}
+
+static int run(int argc, char *argv[]) {
+        _cleanup_close_ int outfd = -1, errfd = -1, saved_stderr = -1;
+        int r;
+
+        log_parse_environment();
+        log_open();
+
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                return r;
+
+        outfd = sd_journal_stream_fd(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);
+                if (errfd < 0)
+                        return log_error_errno(errfd, "Failed to create stream fd: %m");
+        }
+
+        saved_stderr = fcntl(STDERR_FILENO, F_DUPFD_CLOEXEC, 3);
+
+        r = rearrange_stdio(STDIN_FILENO, outfd, errfd < 0 ? outfd : errfd); /* Invalidates fd on succcess + error! */
+        TAKE_FD(outfd);
+        TAKE_FD(errfd);
+        if (r < 0)
+                return log_error_errno(r, "Failed to rearrange stdout/stderr: %m");
+
+        if (argc <= optind)
+                (void) execl("/bin/cat", "/bin/cat", NULL);
+        else
+                (void) execvp(argv[optind], argv + optind);
+        r = -errno;
+
+        /* Let's try to restore a working stderr, so we can print the error message */
+        if (saved_stderr >= 0)
+                (void) dup3(saved_stderr, STDERR_FILENO, 0);
+
+        return log_error_errno(r, "Failed to execute process: %m");
+}
+
+DEFINE_MAIN_FUNCTION(run);