src/journal/cat.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <getopt.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <unistd.h>
   9
  10 #include "sd-journal.h"
  11
  12 #include "alloc-util.h"
  13 #include "fd-util.h"
  14 #include "main-func.h"
  15 #include "parse-util.h"
  16 #include "pretty-print.h"
  17 #include "string-util.h"
  18 #include "syslog-util.h"
  19 #include "terminal-util.h"
  20 #include "util.h"
  21
  22 static const char *arg_identifier = NULL;
  23 static int arg_priority = LOG_INFO;
  24 static int arg_stderr_priority = -1;
  25 static bool arg_level_prefix = true;
  26
  27 static int help(void) {
  28         _cleanup_free_ char *link = NULL;
  29         int r;
  30
  31         r = terminal_urlify_man("systemd-cat", "1", &link);
  32         if (r < 0)
  33                 return log_oom();
  34
  35         printf("%s [OPTIONS...] COMMAND ...\n"
  36                "\n%sExecute process with stdout/stderr connected to the journal.%s\n\n"
  37                "  -h --help                      Show this help\n"
  38                "     --version                   Show package version\n"
  39                "  -t --identifier=STRING         Set syslog identifier\n"
  40                "  -p --priority=PRIORITY         Set priority value (0..7)\n"
  41                "     --stderr-priority=PRIORITY  Set priority value (0..7) used for stderr\n"
  42                "     --level-prefix=BOOL         Control whether level prefix shall be parsed\n"
  43                "\nSee the %s for details.\n"
  44                , program_invocation_short_name
  45                , ansi_highlight(), ansi_normal()
  46                , link
  47         );
  48
  49         return 0;
  50 }
  51
  52 static int parse_argv(int argc, char *argv[]) {
  53
  54         enum {
  55                 ARG_VERSION = 0x100,
  56                 ARG_STDERR_PRIORITY,
  57                 ARG_LEVEL_PREFIX
  58         };
  59
  60         static const struct option options[] = {
  61                 { "help",            no_argument,       NULL, 'h'                 },
  62                 { "version",         no_argument,       NULL, ARG_VERSION         },
  63                 { "identifier",      required_argument, NULL, 't'                 },
  64                 { "priority",        required_argument, NULL, 'p'                 },
  65                 { "stderr-priority", required_argument, NULL, ARG_STDERR_PRIORITY },
  66                 { "level-prefix",    required_argument, NULL, ARG_LEVEL_PREFIX    },
  67                 {}
  68         };
  69
  70         int c;
  71
  72         assert(argc >= 0);
  73         assert(argv);
  74
  75         while ((c = getopt_long(argc, argv, "+ht:p:", options, NULL)) >= 0)
  76
  77                 switch (c) {
  78
  79                 case 'h':
  80                         help();
  81                         return 0;
  82
  83                 case ARG_VERSION:
  84                         return version();
  85
  86                 case 't':
  87                         if (isempty(optarg))
  88                                 arg_identifier = NULL;
  89                         else
  90                                 arg_identifier = optarg;
  91                         break;
  92
  93                 case 'p':
  94                         arg_priority = log_level_from_string(optarg);
  95                         if (arg_priority < 0)
  96                                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
  97                                                        "Failed to parse priority value.");
  98                         break;
  99
 100                 case ARG_STDERR_PRIORITY:
 101                         arg_stderr_priority = log_level_from_string(optarg);
 102                         if (arg_stderr_priority < 0)
 103                                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 104                                                        "Failed to parse stderr priority value.");
 105                         break;
 106
 107                 case ARG_LEVEL_PREFIX: {
 108                         int k;
 109
 110                         k = parse_boolean(optarg);
 111                         if (k < 0)
 112                                 return log_error_errno(k, "Failed to parse level prefix value.");
 113
 114                         arg_level_prefix = k;
 115                         break;
 116                 }
 117
 118                 case '?':
 119                         return -EINVAL;
 120
 121                 default:
 122                         assert_not_reached("Unhandled option");
 123                 }
 124
 125         return 1;
 126 }
 127
 128 static int run(int argc, char *argv[]) {
 129         _cleanup_close_ int outfd = -1, errfd = -1, saved_stderr = -1;
 130         int r;
 131
 132         log_setup_cli();
 133
 134         r = parse_argv(argc, argv);
 135         if (r <= 0)
 136                 return r;
 137
 138         outfd = sd_journal_stream_fd(arg_identifier, arg_priority, arg_level_prefix);
 139         if (outfd < 0)
 140                 return log_error_errno(outfd, "Failed to create stream fd: %m");
 141
 142         if (arg_stderr_priority >= 0 && arg_stderr_priority != arg_priority) {
 143                 errfd = sd_journal_stream_fd(arg_identifier, arg_stderr_priority, arg_level_prefix);
 144                 if (errfd < 0)
 145                         return log_error_errno(errfd, "Failed to create stream fd: %m");
 146         }
 147
 148         saved_stderr = fcntl(STDERR_FILENO, F_DUPFD_CLOEXEC, 3);
 149
 150         r = rearrange_stdio(STDIN_FILENO, outfd, errfd < 0 ? outfd : errfd); /* Invalidates fd on success + error! */
 151         TAKE_FD(outfd);
 152         TAKE_FD(errfd);
 153         if (r < 0)
 154                 return log_error_errno(r, "Failed to rearrange stdout/stderr: %m");
 155
 156         if (argc <= optind)
 157                 (void) execl("/bin/cat", "/bin/cat", NULL);
 158         else
 159                 (void) execvp(argv[optind], argv + optind);
 160         r = -errno;
 161
 162         /* Let's try to restore a working stderr, so we can print the error message */
 163         if (saved_stderr >= 0)
 164                 (void) dup3(saved_stderr, STDERR_FILENO, 0);
 165
 166         return log_error_errno(r, "Failed to execute process: %m");
 167 }
 168
 169 DEFINE_MAIN_FUNCTION(run);