lib/util/util_runcmd.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    run a child command
   5
   6    Copyright (C) Andrew Tridgell 2010
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20
  21 */
  22
  23 /*
  24   this runs a child command with stdout and stderr going to the Samba
  25   log
  26  */
  27
  28 #include "includes.h"
  29 #include "system/filesys.h"
  30 #include "../lib/util/tevent_unix.h"
  31 #include "../lib/util/util_runcmd.h"
  32 #include "../lib/util/tfork.h"
  33 #include "../lib/util/sys_rw.h"
  34
  35 static void samba_runcmd_cleanup_fn(struct tevent_req *req,
  36                                     enum tevent_req_state req_state)
  37 {
  38         struct samba_runcmd_state *state = tevent_req_data(
  39                 req, struct samba_runcmd_state);
  40
  41         if (state->tfork != NULL) {
  42                 tfork_destroy(&state->tfork);
  43         }
  44         state->pid = -1;
  45
  46         if (state->fd_stdin != -1) {
  47                 close(state->fd_stdin);
  48                 state->fd_stdin = -1;
  49         }
  50 }
  51
  52 static void samba_runcmd_io_handler(struct tevent_context *ev,
  53                                     struct tevent_fd *fde,
  54                                     uint16_t flags,
  55                                     void *private_data);
  56
  57 /*
  58   run a command as a child process, with a timeout.
  59
  60   any stdout/stderr from the child will appear in the Samba logs with
  61   the specified log levels
  62  */
  63 struct tevent_req *samba_runcmd_send(TALLOC_CTX *mem_ctx,
  64                                      struct tevent_context *ev,
  65                                      struct timeval endtime,
  66                                      int stdout_log_level,
  67                                      int stderr_log_level,
  68                                      const char * const *argv0, ...)
  69 {
  70         struct tevent_req *req;
  71         struct samba_runcmd_state *state;
  72         int p1[2], p2[2], p3[2];
  73         char **argv;
  74         va_list ap;
  75
  76         if (argv0 == NULL) {
  77                 return NULL;
  78         }
  79
  80         req = tevent_req_create(mem_ctx, &state,
  81                                 struct samba_runcmd_state);
  82         if (req == NULL) {
  83                 return NULL;
  84         }
  85
  86         state->stdout_log_level = stdout_log_level;
  87         state->stderr_log_level = stderr_log_level;
  88         state->fd_stdin = -1;
  89
  90         state->arg0 = talloc_strdup(state, argv0[0]);
  91         if (tevent_req_nomem(state->arg0, req)) {
  92                 return tevent_req_post(req, ev);
  93         }
  94
  95         if (pipe(p1) != 0) {
  96                 tevent_req_error(req, errno);
  97                 return tevent_req_post(req, ev);
  98         }
  99         if (pipe(p2) != 0) {
 100                 close(p1[0]);
 101                 close(p1[1]);
 102                 tevent_req_error(req, errno);
 103                 return tevent_req_post(req, ev);
 104         }
 105         if (pipe(p3) != 0) {
 106                 close(p1[0]);
 107                 close(p1[1]);
 108                 close(p2[0]);
 109                 close(p2[1]);
 110                 tevent_req_error(req, errno);
 111                 return tevent_req_post(req, ev);
 112         }
 113
 114         state->tfork = tfork_create();
 115         if (state->tfork == NULL) {
 116                 close(p1[0]);
 117                 close(p1[1]);
 118                 close(p2[0]);
 119                 close(p2[1]);
 120                 close(p3[0]);
 121                 close(p3[1]);
 122                 tevent_req_error(req, errno);
 123                 return tevent_req_post(req, ev);
 124         }
 125         state->pid = tfork_child_pid(state->tfork);
 126         if (state->pid != 0) {
 127                 /* the parent */
 128                 close(p1[1]);
 129                 close(p2[1]);
 130                 close(p3[0]);
 131                 state->fd_stdout = p1[0];
 132                 state->fd_stderr = p2[0];
 133                 state->fd_stdin  = p3[1];
 134                 state->fd_status = tfork_event_fd(state->tfork);
 135
 136                 set_blocking(state->fd_stdout, false);
 137                 set_blocking(state->fd_stderr, false);
 138                 set_blocking(state->fd_stdin,  false);
 139                 set_blocking(state->fd_status, false);
 140
 141                 smb_set_close_on_exec(state->fd_stdin);
 142                 smb_set_close_on_exec(state->fd_stdout);
 143                 smb_set_close_on_exec(state->fd_stderr);
 144                 smb_set_close_on_exec(state->fd_status);
 145
 146                 tevent_req_set_cleanup_fn(req, samba_runcmd_cleanup_fn);
 147
 148                 state->fde_stdout = tevent_add_fd(ev, state,
 149                                                   state->fd_stdout,
 150                                                   TEVENT_FD_READ,
 151                                                   samba_runcmd_io_handler,
 152                                                   req);
 153                 if (tevent_req_nomem(state->fde_stdout, req)) {
 154                         close(state->fd_stdout);
 155                         close(state->fd_stderr);
 156                         close(state->fd_status);
 157                         return tevent_req_post(req, ev);
 158                 }
 159                 tevent_fd_set_auto_close(state->fde_stdout);
 160
 161                 state->fde_stderr = tevent_add_fd(ev, state,
 162                                                   state->fd_stderr,
 163                                                   TEVENT_FD_READ,
 164                                                   samba_runcmd_io_handler,
 165                                                   req);
 166                 if (tevent_req_nomem(state->fde_stdout, req)) {
 167                         close(state->fd_stdout);
 168                         close(state->fd_stderr);
 169                         close(state->fd_status);
 170                         return tevent_req_post(req, ev);
 171                 }
 172                 tevent_fd_set_auto_close(state->fde_stderr);
 173
 174                 state->fde_status = tevent_add_fd(ev, state,
 175                                                   state->fd_status,
 176                                                   TEVENT_FD_READ,
 177                                                   samba_runcmd_io_handler,
 178                                                   req);
 179                 if (tevent_req_nomem(state->fde_stdout, req)) {
 180                         close(state->fd_stdout);
 181                         close(state->fd_stderr);
 182                         close(state->fd_status);
 183                         return tevent_req_post(req, ev);
 184                 }
 185                 tevent_fd_set_auto_close(state->fde_status);
 186
 187                 if (!timeval_is_zero(&endtime)) {
 188                         tevent_req_set_endtime(req, ev, endtime);
 189                 }
 190
 191                 return req;
 192         }
 193
 194         /* the child */
 195         close(p1[0]);
 196         close(p2[0]);
 197         close(p3[1]);
 198         close(0);
 199         close(1);
 200         close(2);
 201
 202         /* we want to ensure that all of the network sockets we had
 203            open are closed */
 204         tevent_re_initialise(ev);
 205
 206         /* setup for logging to go to the parents debug log */
 207         dup2(p3[0], 0);
 208         dup2(p1[1], 1);
 209         dup2(p2[1], 2);
 210
 211         close(p1[1]);
 212         close(p2[1]);
 213         close(p3[0]);
 214
 215         argv = str_list_copy(state, discard_const_p(const char *, argv0));
 216         if (!argv) {
 217                 fprintf(stderr, "Out of memory in child\n");
 218                 _exit(255);
 219         }
 220
 221         va_start(ap, argv0);
 222         while (1) {
 223                 const char **l;
 224                 char *arg = va_arg(ap, char *);
 225                 if (arg == NULL) break;
 226                 l = discard_const_p(const char *, argv);
 227                 l = str_list_add(l, arg);
 228                 if (l == NULL) {
 229                         fprintf(stderr, "Out of memory in child\n");
 230                         _exit(255);
 231                 }
 232                 argv = discard_const_p(char *, l);
 233         }
 234         va_end(ap);
 235
 236         (void)execvp(state->arg0, argv);
 237         fprintf(stderr, "Failed to exec child - %s\n", strerror(errno));
 238         _exit(255);
 239         return NULL;
 240 }
 241
 242 /*
 243   handle stdout/stderr from the child
 244  */
 245 static void samba_runcmd_io_handler(struct tevent_context *ev,
 246                                     struct tevent_fd *fde,
 247                                     uint16_t flags,
 248                                     void *private_data)
 249 {
 250         struct tevent_req *req = talloc_get_type_abort(private_data,
 251                                  struct tevent_req);
 252         struct samba_runcmd_state *state = tevent_req_data(req,
 253                                            struct samba_runcmd_state);
 254         int level;
 255         char *p;
 256         int n, fd;
 257
 258         if (!(flags & TEVENT_FD_READ)) {
 259                 return;
 260         }
 261
 262         if (fde == state->fde_stdout) {
 263                 level = state->stdout_log_level;
 264                 fd = state->fd_stdout;
 265         } else if (fde == state->fde_stderr) {
 266                 level = state->stderr_log_level;
 267                 fd = state->fd_stderr;
 268         } else {
 269                 int status;
 270
 271                 status = tfork_status(&state->tfork, false);
 272                 if (status == -1) {
 273                         if (errno == EAGAIN || errno == EWOULDBLOCK) {
 274                                 return;
 275                         }
 276                         DBG_ERR("Bad read on status pipe\n");
 277                         tevent_req_error(req, errno);
 278                         return;
 279                 }
 280                 state->pid = -1;
 281                 TALLOC_FREE(fde);
 282
 283                 if (WIFEXITED(status)) {
 284                         status = WEXITSTATUS(status);
 285                 } else if (WIFSIGNALED(status)) {
 286                         status = WTERMSIG(status);
 287                 } else {
 288                         status = ECHILD;
 289                 }
 290
 291                 DBG_NOTICE("Child %s exited %d\n", state->arg0, status);
 292                 if (status != 0) {
 293                         tevent_req_error(req, status);
 294                         return;
 295                 }
 296
 297                 tevent_req_done(req);
 298                 return;
 299         }
 300
 301         n = read(fd, &state->buf[state->buf_used],
 302                  sizeof(state->buf) - state->buf_used);
 303         if (n > 0) {
 304                 state->buf_used += n;
 305         } else if (n == 0) {
 306                 if (fde == state->fde_stdout) {
 307                         talloc_free(fde);
 308                         state->fde_stdout = NULL;
 309                         return;
 310                 }
 311                 if (fde == state->fde_stderr) {
 312                         talloc_free(fde);
 313                         state->fde_stderr = NULL;
 314                         return;
 315                 }
 316                 return;
 317         }
 318
 319         while (state->buf_used > 0 &&
 320                (p = (char *)memchr(state->buf, '\n', state->buf_used)) != NULL) {
 321                 int n1 = (p - state->buf)+1;
 322                 int n2 = n1 - 1;
 323                 /* swallow \r from child processes */
 324                 if (n2 > 0 && state->buf[n2-1] == '\r') {
 325                         n2--;
 326                 }
 327                 DEBUG(level,("%s: %*.*s\n", state->arg0, n2, n2, state->buf));
 328                 memmove(state->buf, p+1, sizeof(state->buf) - n1);
 329                 state->buf_used -= n1;
 330         }
 331
 332         /* the buffer could have completely filled - unfortunately we have
 333            no choice but to dump it out straight away */
 334         if (state->buf_used == sizeof(state->buf)) {
 335                 DEBUG(level,("%s: %*.*s\n",
 336                              state->arg0, state->buf_used,
 337                              state->buf_used, state->buf));
 338                 state->buf_used = 0;
 339         }
 340 }
 341
 342 int samba_runcmd_recv(struct tevent_req *req, int *perrno)
 343 {
 344         if (tevent_req_is_unix_error(req, perrno)) {
 345                 tevent_req_received(req);
 346                 return -1;
 347         }
 348
 349         tevent_req_received(req);
 350         return 0;
 351 }