src/main/exec.c

   1 /*
   2  * exec.c       Execute external programs.
   3  *
   4  * Version:     $Id$
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  * Copyright 2000  The FreeRADIUS server project
  21  * Copyright 2000  Michael J. Hartwick <hartwick@hartwick.com>
  22  */
  23 static const char rcsid[] = "$Id$";
  24
  25 #include "autoconf.h"
  26
  27 #include <sys/file.h>
  28
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <fcntl.h>
  32 #include <ctype.h>
  33 #include <signal.h>
  34
  35 #if HAVE_SYS_WAIT_H
  36 #       include <sys/wait.h>
  37 #endif
  38 #ifndef WEXITSTATUS
  39 #       define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8)
  40 #endif
  41 #ifndef WIFEXITED
  42 #       define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
  43 #endif
  44
  45 #include "radiusd.h"
  46 #include "rad_assert.h"
  47
  48 #ifndef HAVE_PTHREAD_H
  49 #define rad_fork(n) fork()
  50 #define rad_waitpid waitpid
  51 #endif
  52
  53 /*
  54  *      Execute a program on successful authentication.
  55  *      Return 0 if exec_wait == 0.
  56  *      Return the exit code of the called program if exec_wait != 0.
  57  *      Return -1 on fork/other errors in the parent process.
  58  */
  59 int radius_exec_program(const char *cmd, REQUEST *request,
  60                         int exec_wait, const char **user_msg)
  61 {
  62         VALUE_PAIR *vp;
  63         static char message[256];
  64         char answer[4096];
  65         char *argv[256];
  66         char *buf, *p;
  67         int pd[2];
  68         pid_t pid, child_pid;
  69         int argc = -1;
  70         int comma = 0;
  71         int status;
  72         int n, left, done;
  73
  74         /*
  75          *      Open a pipe for child/parent communication, if
  76          *      necessary.
  77          */
  78         if (exec_wait) {
  79                 if (pipe(pd) != 0) {
  80                         radlog(L_ERR|L_CONS, "Couldn't open pipe: %s",
  81                                strerror(errno));
  82                         return -1;
  83                 }
  84         }
  85
  86         /*
  87          *      Do the translation (as the parent) of the command to
  88          *      execute.  This MAY involve calling other modules, so
  89          *      we want to do it in the parent.
  90          */
  91         radius_xlat(answer, sizeof(answer), cmd, request, NULL);
  92         buf = answer;
  93
  94         /*
  95          *      Log the command if we are debugging something
  96          */
  97         DEBUG("Exec-Program: %s", buf);
  98
  99         /*
 100          *      Build vector list of arguments and execute.
 101          *
 102          *      FIXME: This parsing gets excited over spaces in
 103          *      the translated strings, e.g. User-Name = "aa bb"
 104          *      is passed as two seperate arguments, instead of one.
 105          *
 106          *      What we SHOULD do instead is to split the exec program
 107          *      buffer first, and then do the translation on every
 108          *      subsequent string.
 109          */
 110         p = strtok(buf, " \t");
 111         if (p) do {
 112                 argv[++argc] = p;
 113                 p = strtok(NULL, " \t");
 114         } while(p != NULL);
 115
 116         argv[++argc] = p;
 117         if (argc == 0) {
 118                 radlog(L_ERR, "Exec-Program: empty command line.");
 119                 return -1;
 120         }
 121
 122         if ((pid = rad_fork(exec_wait)) == 0) {
 123 #define MAX_ENVP 1024
 124                 int i, devnull;
 125                 char *envp[MAX_ENVP];
 126                 int envlen;
 127                 char buffer[1024];
 128
 129                 /*
 130                  *      Child process.
 131                  *
 132                  *      We try to be fail-safe here.  So if ANYTHING
 133                  *      goes wrong, we exit with status 1.
 134                  */
 135
 136                 /*
 137                  *      Open STDIN to /dev/null
 138                  */
 139                 devnull = open("/dev/null", O_RDWR);
 140                 if (devnull < 0) {
 141                         radlog(L_ERR|L_CONS, "Failed opening /dev/null: %s\n",
 142                                strerror(errno));
 143                         exit(1);
 144                 }
 145                 dup2(devnull, STDIN_FILENO);
 146
 147                 /*
 148                  *      Only massage the pipe handles if the parent
 149                  *      has created them.
 150                  */
 151                 if (exec_wait) {
 152                         /*
 153                          *      pd[0] is the FD the child will read from,
 154                          *      which we don't want.
 155                          */
 156                         if (close(pd[0]) != 0) {
 157                                 radlog(L_ERR|L_CONS, "Can't close pipe: %s",
 158                                        strerror(errno));
 159                                 exit(1);
 160                         }
 161
 162                         /*
 163                          *      pd[1] is the FD that the child will write to,
 164                          *      so we make it STDOUT.
 165                          */
 166                         if (dup2(pd[1], STDOUT_FILENO) != 1) {
 167                                 radlog(L_ERR|L_CONS, "Can't dup stdout: %s",
 168                                        strerror(errno));
 169                                 exit(1);
 170                         }
 171
 172                 } else {        /* no pipe, STDOUT should be /dev/null */
 173                         dup2(devnull, STDOUT_FILENO);
 174                 }
 175
 176                 /*
 177                  *      If we're not debugging, then we can't do
 178                  *      anything with the error messages, so we throw
 179                  *      them away.
 180                  *
 181                  *      If we are debugging, then we want the error
 182                  *      messages to go to the STDERR of the server.
 183                  */
 184                 if (debug_flag == 0) {
 185                         dup2(devnull, STDERR_FILENO);
 186                 }
 187                 close(devnull);
 188
 189                 /*
 190                  *      The server may have MANY FD's open.  We don't
 191                  *      want to leave dangling FD's for the child process
 192                  *      to play funky games with, so we close them.
 193                  */
 194                 for (i = 3; i < 256; i++) {
 195                         close(i);
 196                 }
 197
 198                 /*
 199                  *      Set up the environment variables.
 200                  *      We're in the child, and it will exit in 4 lines
 201                  *      anyhow, so memory allocation isn't an issue.
 202                  */
 203                 envlen = 0;
 204
 205                 for (vp = request->packet->vps; vp->next; vp = vp->next) {
 206                         /*
 207                          *      Hmm... maybe we shouldn't pass the
 208                          *      user's password in an environment
 209                          *      variable...
 210                          */
 211                         snprintf(buffer, sizeof(buffer), "%s=", vp->name);
 212                         for (p = buffer; *p != '='; p++) {
 213                                 if (*p == '-') {
 214                                         *p = '_';
 215                                 } else if (isalpha(*p)) {
 216                                         *p = toupper(*p);
 217                                 }
 218                         }
 219
 220                         n = strlen(buffer);
 221                         vp_prints_value(buffer+n, sizeof(buffer) - n, vp, 1);
 222
 223                         envp[envlen++] = strdup(buffer);
 224                 }
 225                 envp[envlen] = NULL;
 226
 227                 execve(argv[0], argv, envp);
 228
 229                 radlog(L_ERR, "Exec-Program: FAILED to execute %s: %s",
 230                        argv[0], strerror(errno));
 231                 exit(1);
 232         }
 233
 234         /*
 235          *      Parent process.
 236          */
 237         if (pid < 0) {
 238                 radlog(L_ERR|L_CONS, "Couldn't fork %s: %s",
 239                        argv[0], strerror(errno));
 240                 return -1;
 241         }
 242
 243         /*
 244          *      We're not waiting, exit, and ignore any child's
 245          *      status.
 246          */
 247         if (!exec_wait) {
 248                 return 0;
 249         }
 250
 251         /*
 252          *      Close the FD to which the child writes it's data.
 253          *
 254          *      If we can't close it, then we close pd[0], and return an
 255          *      error.
 256          */
 257         if (close(pd[1]) != 0) {
 258                 radlog(L_ERR|L_CONS, "Can't close pipe: %s", strerror(errno));
 259                 close(pd[0]);
 260                 return -1;
 261         }
 262
 263         /*
 264          *      Read from the pipe until we doesn't get any more or
 265          *      until the message is full.
 266          */
 267         done = 0;
 268         left = sizeof(answer) - 1;
 269         while (1) {
 270                 status = read(pd[0], answer + done, left);
 271                 /*
 272                  *      Nothing more to read: stop.
 273                  */
 274                 if (status == 0) {
 275                         break;
 276                 }
 277
 278                 /*
 279                  *      Error: See if we have to continue.
 280                  */
 281                 if (status < 0) {
 282                         /*
 283                          *      We were interrupted: continue reading.
 284                          */
 285                         if (errno == EINTR) {
 286                                 continue;
 287                         }
 288
 289                         /*
 290                          *      There was another error.  Most likely
 291                          *      The child process has finished, and
 292                          *      exited.
 293                          */
 294                         break;
 295                 }
 296
 297                 done += status;
 298                 left -= status;
 299                 if (left <= 0) break;
 300         }
 301         answer[done] = 0;
 302
 303         /*
 304          *      Make sure that the writer can't block while writing to
 305          *      a pipe that no one is reading from anymore.
 306          */
 307         close(pd[0]);
 308
 309         /*
 310          *      Parse the output, if any.
 311          */
 312         if (done) {
 313                 /*
 314                  *      For backwards compatibility, first check
 315                  *      for plain text (user_msg).
 316                  */
 317                 vp = NULL;
 318                 n = userparse(answer, &vp);
 319                 if (vp) {
 320                         pairfree(&vp);
 321                 }
 322
 323                 if (n < 0) {
 324                         radlog(L_DBG, "Exec-Program-Wait: plaintext: %s", answer);
 325                         if (user_msg) {
 326                                 strncpy(message, answer, sizeof(message));
 327                                 message[sizeof(message) - 1] = 0;
 328                                 *user_msg = message;
 329                         }
 330                 } else {
 331                         /*
 332                          *      HACK: Replace '\n' with ',' so that
 333                          *      userparse() can parse the buffer in
 334                          *      one go (the proper way would be to
 335                          *      fix userparse(), but oh well).
 336                          */
 337                         for (p = answer; *p; p++) {
 338                                 if (*p == '\n') {
 339                                         *p = comma ? ' ' : ',';
 340                                         p++;
 341                                         comma = 0;
 342                                 }
 343                                 if (*p == ',') comma++;
 344                         }
 345
 346                         /*
 347                          *  Replace any trailing comma by a NUL.
 348                          */
 349                         if (answer[strlen(answer) - 1] == ',') {
 350                                 answer[strlen(answer) - 1] = '\0';
 351                         }
 352
 353                         radlog(L_DBG,"Exec-Program-Wait: value-pairs: %s", answer);
 354                         if (userparse(answer, &vp) < 0) {
 355                                 radlog(L_ERR, "Exec-Program-Wait: %s: unparsable reply", cmd);
 356
 357                         } else {
 358                                 /*
 359                                  *      Add the attributes to the reply.
 360                                  */
 361                                 pairmove(&request->reply->vps, &vp);
 362                                 pairfree(&vp);
 363                         }
 364                 } /* else the answer was a set of VP's, not a text message */
 365         } /* else we didn't read anything from the child. */
 366
 367         /*
 368          *      Call rad_waitpid (should map to waitpid on non-threaded
 369          *      or single-server systems).
 370          */
 371         child_pid = rad_waitpid(pid, &status, 0);
 372         if (child_pid == pid) {
 373                 if (WIFEXITED(status)) {
 374                         status = WEXITSTATUS(status);
 375                         radlog(L_DBG, "Exec-Program: returned: %d", status);
 376                         return status;
 377                 }
 378         }
 379
 380         radlog(L_ERR|L_CONS, "Exec-Program: Abnormal child exit");
 381         return 1;
 382 }