src/journal/cat.c

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