src/notify/notify.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6 ***/
   7
   8 #include <errno.h>
   9 #include <getopt.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13
  14 #include "sd-daemon.h"
  15
  16 #include "alloc-util.h"
  17 #include "env-util.h"
  18 #include "format-util.h"
  19 #include "log.h"
  20 #include "parse-util.h"
  21 #include "string-util.h"
  22 #include "strv.h"
  23 #include "user-util.h"
  24 #include "util.h"
  25
  26 static bool arg_ready = false;
  27 static pid_t arg_pid = 0;
  28 static const char *arg_status = NULL;
  29 static bool arg_booted = false;
  30 static uid_t arg_uid = UID_INVALID;
  31 static gid_t arg_gid = GID_INVALID;
  32
  33 static void help(void) {
  34         printf("%s [OPTIONS...] [VARIABLE=VALUE...]\n\n"
  35                "Notify the init system about service status updates.\n\n"
  36                "  -h --help            Show this help\n"
  37                "     --version         Show package version\n"
  38                "     --ready           Inform the init system about service start-up completion\n"
  39                "     --pid[=PID]       Set main PID of daemon\n"
  40                "     --uid=USER        Set user to send from\n"
  41                "     --status=TEXT     Set status text\n"
  42                "     --booted          Check if the system was booted up with systemd\n",
  43                program_invocation_short_name);
  44 }
  45
  46 static int parse_argv(int argc, char *argv[]) {
  47
  48         enum {
  49                 ARG_READY = 0x100,
  50                 ARG_VERSION,
  51                 ARG_PID,
  52                 ARG_STATUS,
  53                 ARG_BOOTED,
  54                 ARG_UID,
  55         };
  56
  57         static const struct option options[] = {
  58                 { "help",      no_argument,       NULL, 'h'           },
  59                 { "version",   no_argument,       NULL, ARG_VERSION   },
  60                 { "ready",     no_argument,       NULL, ARG_READY     },
  61                 { "pid",       optional_argument, NULL, ARG_PID       },
  62                 { "status",    required_argument, NULL, ARG_STATUS    },
  63                 { "booted",    no_argument,       NULL, ARG_BOOTED    },
  64                 { "uid",       required_argument, NULL, ARG_UID       },
  65                 {}
  66         };
  67
  68         int c, r;
  69
  70         assert(argc >= 0);
  71         assert(argv);
  72
  73         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
  74
  75                 switch (c) {
  76
  77                 case 'h':
  78                         help();
  79                         return 0;
  80
  81                 case ARG_VERSION:
  82                         return version();
  83
  84                 case ARG_READY:
  85                         arg_ready = true;
  86                         break;
  87
  88                 case ARG_PID:
  89
  90                         if (optarg) {
  91                                 if (parse_pid(optarg, &arg_pid) < 0) {
  92                                         log_error("Failed to parse PID %s.", optarg);
  93                                         return -EINVAL;
  94                                 }
  95                         } else
  96                                 arg_pid = getppid();
  97
  98                         break;
  99
 100                 case ARG_STATUS:
 101                         arg_status = optarg;
 102                         break;
 103
 104                 case ARG_BOOTED:
 105                         arg_booted = true;
 106                         break;
 107
 108                 case ARG_UID: {
 109                         const char *u = optarg;
 110
 111                         r = get_user_creds(&u, &arg_uid, &arg_gid, NULL, NULL);
 112                         if (r == -ESRCH) /* If the user doesn't exist, then accept it anyway as numeric */
 113                                 r = parse_uid(u, &arg_uid);
 114                         if (r < 0)
 115                                 return log_error_errno(r, "Can't resolve user %s: %m", optarg);
 116
 117                         break;
 118                 }
 119
 120                 case '?':
 121                         return -EINVAL;
 122
 123                 default:
 124                         assert_not_reached("Unhandled option");
 125                 }
 126         }
 127
 128         if (optind >= argc &&
 129             !arg_ready &&
 130             !arg_status &&
 131             !arg_pid &&
 132             !arg_booted) {
 133                 help();
 134                 return -EINVAL;
 135         }
 136
 137         return 1;
 138 }
 139
 140 int main(int argc, char* argv[]) {
 141         _cleanup_free_ char *status = NULL, *cpid = NULL, *n = NULL;
 142         _cleanup_strv_free_ char **final_env = NULL;
 143         char* our_env[4];
 144         unsigned i = 0;
 145         int r;
 146
 147         log_parse_environment();
 148         log_open();
 149
 150         r = parse_argv(argc, argv);
 151         if (r <= 0)
 152                 goto finish;
 153
 154         if (arg_booted)
 155                 return sd_booted() <= 0;
 156
 157         if (arg_ready)
 158                 our_env[i++] = (char*) "READY=1";
 159
 160         if (arg_status) {
 161                 status = strappend("STATUS=", arg_status);
 162                 if (!status) {
 163                         r = log_oom();
 164                         goto finish;
 165                 }
 166
 167                 our_env[i++] = status;
 168         }
 169
 170         if (arg_pid > 0) {
 171                 if (asprintf(&cpid, "MAINPID="PID_FMT, arg_pid) < 0) {
 172                         r = log_oom();
 173                         goto finish;
 174                 }
 175
 176                 our_env[i++] = cpid;
 177         }
 178
 179         our_env[i++] = NULL;
 180
 181         final_env = strv_env_merge(2, our_env, argv + optind);
 182         if (!final_env) {
 183                 r = log_oom();
 184                 goto finish;
 185         }
 186
 187         if (strv_isempty(final_env)) {
 188                 r = 0;
 189                 goto finish;
 190         }
 191
 192         n = strv_join(final_env, "\n");
 193         if (!n) {
 194                 r = log_oom();
 195                 goto finish;
 196         }
 197
 198         /* If this is requested change to the requested UID/GID. Note thta we only change the real UID here, and leave
 199            the effective UID in effect (which is 0 for this to work). That's because we want the privileges to fake the
 200            ucred data, and sd_pid_notify() uses the real UID for filling in ucred. */
 201
 202         if (arg_gid != GID_INVALID)
 203                 if (setregid(arg_gid, (gid_t) -1) < 0) {
 204                         r = log_error_errno(errno, "Failed to change GID: %m");
 205                         goto finish;
 206                 }
 207
 208         if (arg_uid != UID_INVALID)
 209                 if (setreuid(arg_uid, (uid_t) -1) < 0) {
 210                         r = log_error_errno(errno, "Failed to change UID: %m");
 211                         goto finish;
 212                 }
 213
 214         r = sd_pid_notify(arg_pid ? arg_pid : getppid(), false, n);
 215         if (r < 0) {
 216                 log_error_errno(r, "Failed to notify init system: %m");
 217                 goto finish;
 218         } else if (r == 0) {
 219                 log_error("No status data could be sent: $NOTIFY_SOCKET was not set");
 220                 r = -EOPNOTSUPP;
 221         }
 222
 223 finish:
 224         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 225 }