usr.bin/at/at.c

   1 /*
   2  *  at.c : Put file into atrun queue
   3  *  Copyright (C) 1993, 1994 Thomas Koenig
   4  *
   5  *  Atrun & Atq modifications
   6  *  Copyright (C) 1993  David Parsons
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. The name of the author(s) may not be used to endorse or promote
  14  *    products derived from this software without specific prior written
  15  *    permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * $FreeBSD: src/usr.bin/at/at.c,v 1.18.2.1 2001/08/02 00:55:58 obrien Exp $
  29  * $DragonFly: src/usr.bin/at/at.c,v 1.6 2006/03/29 21:37:43 swildner Exp $
  30  */
  31
  32 #define _USE_BSD 1
  33
  34 /* System Headers */
  35
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <sys/wait.h>
  39 #include <sys/param.h>
  40 #include <ctype.h>
  41 #include <dirent.h>
  42 #include <err.h>
  43 #include <errno.h>
  44 #include <fcntl.h>
  45 #include <pwd.h>
  46 #include <signal.h>
  47 #include <stddef.h>
  48 #include <stdio.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <time.h>
  52 #include <unistd.h>
  53 #include <utmp.h>
  54 #include <locale.h>
  55
  56 #if (MAXLOGNAME-1) > UT_NAMESIZE
  57 #define LOGNAMESIZE UT_NAMESIZE
  58 #else
  59 #define LOGNAMESIZE (MAXLOGNAME-1)
  60 #endif
  61
  62 /* Local headers */
  63
  64 #include "at.h"
  65 #include "panic.h"
  66 #include "parsetime.h"
  67 #include "perm.h"
  68
  69 #define MAIN
  70 #include "privs.h"
  71
  72 /* Macros */
  73
  74 #ifndef ATJOB_DIR
  75 #define ATJOB_DIR "/usr/spool/atjobs/"
  76 #endif
  77
  78 #ifndef LFILE
  79 #define LFILE ATJOB_DIR ".lockfile"
  80 #endif
  81
  82 #ifndef ATJOB_MX
  83 #define ATJOB_MX 255
  84 #endif
  85
  86 #define ALARMC 10 /* Number of seconds to wait for timeout */
  87
  88 #define SIZE 255
  89 #define TIMESIZE 50
  90
  91 enum { ATQ, ATRM, AT, BATCH, CAT };     /* what program we want to run */
  92
  93 /* File scope variables */
  94
  95 const char *no_export[] =
  96 {
  97     "TERM", "TERMCAP", "DISPLAY", "_"
  98 } ;
  99 static int send_mail = 0;
 100
 101 /* External variables */
 102 uid_t real_uid, effective_uid;
 103 gid_t real_gid, effective_gid;
 104
 105 extern char **environ;
 106 int fcreated;
 107 char atfile[sizeof(ATJOB_DIR) + 14] = ATJOB_DIR;
 108
 109 char *atinput = NULL;           /* where to get input from */
 110 char atqueue = 0;               /* which queue to examine for jobs (atq) */
 111 char atverify = 0;              /* verify time instead of queuing job */
 112
 113 /* Function declarations */
 114
 115 static void sigc(int signo);
 116 static void alarmc(int signo);
 117 static char *cwdname(void);
 118 static void writefile(time_t runtimer, char queue);
 119 static void list_jobs(void);
 120
 121 /* Signal catching functions */
 122
 123 static
 124 void sigc(int signo __unused)
 125 {
 126 /* If the user presses ^C, remove the spool file and exit
 127  */
 128     if (fcreated)
 129     {
 130         PRIV_START
 131             unlink(atfile);
 132         PRIV_END
 133     }
 134
 135     exit(EXIT_FAILURE);
 136 }
 137
 138 static
 139 void alarmc(int sign __unused)
 140 {
 141 /* Time out after some seconds
 142  */
 143     panic("file locking timed out");
 144 }
 145
 146 /* Local functions */
 147
 148 static char *cwdname(void)
 149 {
 150 /* Read in the current directory; the name will be overwritten on
 151  * subsequent calls.
 152  */
 153     static char *ptr = NULL;
 154     static size_t size = SIZE;
 155
 156     if (ptr == NULL)
 157         if ((ptr = malloc(size)) == NULL)
 158             errx(EXIT_FAILURE, "virtual memory exhausted");
 159
 160     while (1)
 161     {
 162         if (ptr == NULL)
 163             panic("out of memory");
 164
 165         if (getcwd(ptr, size-1) != NULL)
 166             return ptr;
 167
 168         if (errno != ERANGE)
 169             perr("cannot get directory");
 170
 171         free (ptr);
 172         size += SIZE;
 173         if ((ptr = malloc(size)) == NULL)
 174             errx(EXIT_FAILURE, "virtual memory exhausted");
 175     }
 176 }
 177
 178 static long
 179 nextjob(void)
 180 {
 181     long jobno;
 182     FILE *fid;
 183
 184     if ((fid = fopen(ATJOB_DIR ".SEQ", "r+")) != (FILE*)0) {
 185         if (fscanf(fid, "%5lx", &jobno) == 1) {
 186             rewind(fid);
 187             jobno = (1+jobno) % 0xfffff;        /* 2^20 jobs enough? */
 188             fprintf(fid, "%05lx\n", jobno);
 189         }
 190         else
 191             jobno = EOF;
 192         fclose(fid);
 193         return jobno;
 194     }
 195     else if ((fid = fopen(ATJOB_DIR ".SEQ", "w")) != (FILE*)0) {
 196         fprintf(fid, "%05lx\n", jobno = 1);
 197         fclose(fid);
 198         return 1;
 199     }
 200     return EOF;
 201 }
 202
 203 static void
 204 writefile(time_t runtimer, char queue)
 205 {
 206 /* This does most of the work if at or batch are invoked for writing a job.
 207  */
 208     long jobno;
 209     char *ap, *ppos, *mailname;
 210     struct passwd *pass_entry;
 211     struct stat statbuf;
 212     int fdes, lockdes, fd2;
 213     FILE *fp, *fpin;
 214     struct sigaction act;
 215     char **atenv;
 216     int ch;
 217     mode_t cmask;
 218     struct flock lock;
 219
 220     setlocale(LC_TIME, "");
 221
 222 /* Install the signal handler for SIGINT; terminate after removing the
 223  * spool file if necessary
 224  */
 225     act.sa_handler = sigc;
 226     sigemptyset(&(act.sa_mask));
 227     act.sa_flags = 0;
 228
 229     sigaction(SIGINT, &act, NULL);
 230
 231     /* Loop over all possible file names for running something at this
 232      * particular time, see if a file is there; the first empty slot at any
 233      * particular time is used.  Lock the file LFILE first to make sure
 234      * we're alone when doing this.
 235      */
 236
 237     PRIV_START
 238
 239     if ((lockdes = open(LFILE, O_WRONLY | O_CREAT, S_IWUSR | S_IRUSR)) < 0)
 240         perr("cannot open lockfile " LFILE);
 241
 242     lock.l_type = F_WRLCK; lock.l_whence = SEEK_SET; lock.l_start = 0;
 243     lock.l_len = 0;
 244
 245     act.sa_handler = alarmc;
 246     sigemptyset(&(act.sa_mask));
 247     act.sa_flags = 0;
 248
 249     /* Set an alarm so a timeout occurs after ALARMC seconds, in case
 250      * something is seriously broken.
 251      */
 252     sigaction(SIGALRM, &act, NULL);
 253     alarm(ALARMC);
 254     fcntl(lockdes, F_SETLKW, &lock);
 255     alarm(0);
 256
 257     if ((jobno = nextjob()) == EOF)
 258         perr("cannot generate job number");
 259
 260     ppos = atfile + strlen(atfile);
 261     snprintf(ppos, sizeof(atfile) - strlen(atfile), "%c%5lx%8lx", queue,
 262              jobno, (unsigned long) (runtimer/60));
 263
 264     for(ap=ppos; *ap != '\0'; ap ++)
 265         if (*ap == ' ')
 266             *ap = '0';
 267
 268     if (stat(atfile, &statbuf) != 0)
 269         if (errno != ENOENT)
 270             perr("cannot access " ATJOB_DIR);
 271
 272     /* Create the file. The x bit is only going to be set after it has
 273      * been completely written out, to make sure it is not executed in the
 274      * meantime.  To make sure they do not get deleted, turn off their r
 275      * bit.  Yes, this is a kluge.
 276      */
 277     cmask = umask(S_IRUSR | S_IWUSR | S_IXUSR);
 278     if ((fdes = creat(atfile, O_WRONLY)) == -1)
 279         perr("cannot create atjob file");
 280
 281     if ((fd2 = dup(fdes)) <0)
 282         perr("error in dup() of job file");
 283
 284     if(fchown(fd2, real_uid, real_gid) != 0)
 285         perr("cannot give away file");
 286
 287     PRIV_END
 288
 289     /* We no longer need suid root; now we just need to be able to write
 290      * to the directory, if necessary.
 291      */
 292
 293     REDUCE_PRIV(DAEMON_UID, DAEMON_GID)
 294
 295     /* We've successfully created the file; let's set the flag so it
 296      * gets removed in case of an interrupt or error.
 297      */
 298     fcreated = 1;
 299
 300     /* Now we can release the lock, so other people can access it
 301      */
 302     lock.l_type = F_UNLCK; lock.l_whence = SEEK_SET; lock.l_start = 0;
 303     lock.l_len = 0;
 304     fcntl(lockdes, F_SETLKW, &lock);
 305     close(lockdes);
 306
 307     if((fp = fdopen(fdes, "w")) == NULL)
 308         panic("cannot reopen atjob file");
 309
 310     /* Get the userid to mail to, first by trying getlogin(), which reads
 311      * /etc/utmp, then from LOGNAME, finally from getpwuid().
 312      */
 313     mailname = getlogin();
 314     if (mailname == NULL)
 315         mailname = getenv("LOGNAME");
 316
 317     if ((mailname == NULL) || (mailname[0] == '\0')
 318         || (strlen(mailname) > LOGNAMESIZE) || (getpwnam(mailname)==NULL))
 319     {
 320         pass_entry = getpwuid(real_uid);
 321         if (pass_entry != NULL)
 322             mailname = pass_entry->pw_name;
 323     }
 324
 325     if (atinput != (char *) NULL)
 326     {
 327         fpin = freopen(atinput, "r", stdin);
 328         if (fpin == NULL)
 329             perr("cannot open input file");
 330     }
 331     fprintf(fp, "#!/bin/sh\n# atrun uid=%ld gid=%ld\n# mail %*s %d\n",
 332         (long) real_uid, (long) real_gid, LOGNAMESIZE, mailname, send_mail);
 333
 334     /* Write out the umask at the time of invocation
 335      */
 336     fprintf(fp, "umask %lo\n", (unsigned long) cmask);
 337
 338     /* Write out the environment. Anything that may look like a
 339      * special character to the shell is quoted, except for \n, which is
 340      * done with a pair of "'s.  Don't export the no_export list (such
 341      * as TERM or DISPLAY) because we don't want these.
 342      */
 343     for (atenv= environ; *atenv != NULL; atenv++)
 344     {
 345         int export = 1;
 346         char *eqp;
 347
 348         eqp = strchr(*atenv, '=');
 349         if (ap == NULL)
 350             eqp = *atenv;
 351         else
 352         {
 353             unsigned int i;
 354             for (i=0; i<sizeof(no_export)/sizeof(no_export[0]); i++)
 355             {
 356                 export = export
 357                     && (strncmp(*atenv, no_export[i],
 358                                 (size_t) (eqp-*atenv)) != 0);
 359             }
 360             eqp++;
 361         }
 362
 363         if (export)
 364         {
 365             fwrite(*atenv, sizeof(char), eqp-*atenv, fp);
 366             for(ap = eqp;*ap != '\0'; ap++)
 367             {
 368                 if (*ap == '\n')
 369                     fprintf(fp, "\"\n\"");
 370                 else
 371                 {
 372                     if (!isalnum(*ap)) {
 373                         switch (*ap) {
 374                           case '%': case '/': case '{': case '[':
 375                           case ']': case '=': case '}': case '@':
 376                           case '+': case '#': case ',': case '.':
 377                           case ':': case '-': case '_':
 378                             break;
 379                           default:
 380                             fputc('\\', fp);
 381                             break;
 382                         }
 383                     }
 384                     fputc(*ap, fp);
 385                 }
 386             }
 387             fputs("; export ", fp);
 388             fwrite(*atenv, sizeof(char), eqp-*atenv -1, fp);
 389             fputc('\n', fp);
 390
 391         }
 392     }
 393     /* Cd to the directory at the time and write out all the
 394      * commands the user supplies from stdin.
 395      */
 396     fprintf(fp, "cd ");
 397     for (ap = cwdname(); *ap != '\0'; ap++)
 398     {
 399         if (*ap == '\n')
 400             fprintf(fp, "\"\n\"");
 401         else
 402         {
 403             if (*ap != '/' && !isalnum(*ap))
 404                 fputc('\\', fp);
 405
 406             fputc(*ap, fp);
 407         }
 408     }
 409     /* Test cd's exit status: die if the original directory has been
 410      * removed, become unreadable or whatever
 411      */
 412     fprintf(fp, " || {\n\t echo 'Execution directory "
 413                 "inaccessible' >&2\n\t exit 1\n}\n");
 414
 415     while((ch = getchar()) != EOF)
 416         fputc(ch, fp);
 417
 418     fprintf(fp, "\n");
 419     if (ferror(fp))
 420         panic("output error");
 421
 422     if (ferror(stdin))
 423         panic("input error");
 424
 425     fclose(fp);
 426
 427     /* Set the x bit so that we're ready to start executing
 428      */
 429
 430     if (fchmod(fd2, S_IRUSR | S_IWUSR | S_IXUSR) < 0)
 431         perr("cannot give away file");
 432
 433     close(fd2);
 434     fprintf(stderr, "Job %ld will be executed using /bin/sh\n", jobno);
 435 }
 436
 437 static void
 438 list_jobs(void)
 439 {
 440     /* List all a user's jobs in the queue, by looping through ATJOB_DIR,
 441      * or everybody's if we are root
 442      */
 443     struct passwd *pw;
 444     DIR *spool;
 445     struct dirent *dirent;
 446     struct stat buf;
 447     struct tm runtime;
 448     unsigned long ctm;
 449     char queue;
 450     long jobno;
 451     time_t runtimer;
 452     char timestr[TIMESIZE];
 453     int first=1;
 454
 455     setlocale(LC_TIME, "");
 456
 457     PRIV_START
 458
 459     if (chdir(ATJOB_DIR) != 0)
 460         perr("cannot change to " ATJOB_DIR);
 461
 462     if ((spool = opendir(".")) == NULL)
 463         perr("cannot open " ATJOB_DIR);
 464
 465     /*  Loop over every file in the directory
 466      */
 467     while((dirent = readdir(spool)) != NULL) {
 468         if (stat(dirent->d_name, &buf) != 0)
 469             perr("cannot stat in " ATJOB_DIR);
 470
 471         /* See it's a regular file and has its x bit turned on and
 472          * is the user's
 473          */
 474         if (!S_ISREG(buf.st_mode)
 475             || ((buf.st_uid != real_uid) && ! (real_uid == 0))
 476             || !(S_IXUSR & buf.st_mode || atverify))
 477             continue;
 478
 479         if(sscanf(dirent->d_name, "%c%5lx%8lx", &queue, &jobno, &ctm)!=3)
 480             continue;
 481
 482         if (atqueue && (queue != atqueue))
 483             continue;
 484
 485         runtimer = 60*(time_t) ctm;
 486         runtime = *localtime(&runtimer);
 487         strftime(timestr, TIMESIZE, "%X %x", &runtime);
 488         if (first) {
 489             printf("Date\t\t\tOwner\tQueue\tJob#\n");
 490             first=0;
 491         }
 492         pw = getpwuid(buf.st_uid);
 493
 494         printf("%s\t%s\t%c%s\t%ld\n",
 495                timestr,
 496                pw ? pw->pw_name : "???",
 497                queue,
 498                (S_IXUSR & buf.st_mode) ? "":"(done)",
 499                jobno);
 500     }
 501     closedir(spool);
 502
 503     PRIV_END
 504 }
 505
 506 static void
 507 process_jobs(int argc, char **argv, int what)
 508 {
 509     /* Delete every argument (job - ID) given
 510      */
 511     int i;
 512     struct stat buf;
 513     DIR *spool;
 514     struct dirent *dirent;
 515     unsigned long ctm;
 516     char queue;
 517     long jobno;
 518
 519     PRIV_START
 520
 521     if (chdir(ATJOB_DIR) != 0)
 522         perr("cannot change to " ATJOB_DIR);
 523
 524     if ((spool = opendir(".")) == NULL)
 525         perr("cannot open " ATJOB_DIR);
 526
 527     PRIV_END
 528
 529     /*  Loop over every file in the directory
 530      */
 531     while((dirent = readdir(spool)) != NULL) {
 532
 533         PRIV_START
 534         if (stat(dirent->d_name, &buf) != 0)
 535             perr("cannot stat in " ATJOB_DIR);
 536         PRIV_END
 537
 538         if(sscanf(dirent->d_name, "%c%5lx%8lx", &queue, &jobno, &ctm)!=3)
 539             continue;
 540
 541         for (i=optind; i < argc; i++) {
 542             if (atoi(argv[i]) == jobno) {
 543                 if ((buf.st_uid != real_uid) && !(real_uid == 0))
 544                     errx(EXIT_FAILURE, "%s: not owner", argv[i]);
 545                 switch (what) {
 546                   case ATRM:
 547
 548                     PRIV_START
 549
 550                     if (unlink(dirent->d_name) != 0)
 551                         perr(dirent->d_name);
 552
 553                     PRIV_END
 554
 555                     break;
 556
 557                   case CAT:
 558                     {
 559                         FILE *fp;
 560                         int ch;
 561
 562                         PRIV_START
 563
 564                         fp = fopen(dirent->d_name,"r");
 565
 566                         PRIV_END
 567
 568                         if (!fp) {
 569                             perr("cannot open file");
 570                         }
 571                         while((ch = getc(fp)) != EOF) {
 572                             putchar(ch);
 573                         }
 574                         fclose(fp);
 575                     }
 576                     break;
 577
 578                   default:
 579                     errx(EXIT_FAILURE, "internal error, process_jobs = %d",
 580                         what);
 581                 }
 582             }
 583         }
 584     }
 585     closedir(spool);
 586 } /* delete_jobs */
 587
 588 int
 589 main(int argc, char **argv)
 590 {
 591     int c;
 592     char queue = DEFAULT_AT_QUEUE;
 593     char queue_set = 0;
 594     char *pgm;
 595
 596     int program = AT;                   /* our default program */
 597     const char *options = "q:f:mvldbVc"; /* default options for at */
 598     int disp_version = 0;
 599     time_t timer;
 600
 601     RELINQUISH_PRIVS
 602
 603     /* Eat any leading paths
 604      */
 605     if ((pgm = strrchr(argv[0], '/')) == NULL)
 606         pgm = argv[0];
 607     else
 608         pgm++;
 609
 610     /* find out what this program is supposed to do
 611      */
 612     if (strcmp(pgm, "atq") == 0) {
 613         program = ATQ;
 614         options = "q:vV";
 615     }
 616     else if (strcmp(pgm, "atrm") == 0) {
 617         program = ATRM;
 618         options = "V";
 619     }
 620     else if (strcmp(pgm, "batch") == 0) {
 621         program = BATCH;
 622         options = "f:q:mvV";
 623     }
 624
 625     /* process whatever options we can process
 626      */
 627     opterr=1;
 628     while ((c=getopt(argc, argv, options)) != -1)
 629         switch (c) {
 630         case 'v':   /* verify time settings */
 631             atverify = 1;
 632             break;
 633
 634         case 'm':   /* send mail when job is complete */
 635             send_mail = 1;
 636             break;
 637
 638         case 'f':
 639             atinput = optarg;
 640             break;
 641
 642         case 'q':    /* specify queue */
 643             if (strlen(optarg) > 1)
 644                 usage();
 645
 646             atqueue = queue = *optarg;
 647             if (!(islower(queue)||isupper(queue)))
 648                 usage();
 649
 650             queue_set = 1;
 651             break;
 652
 653         case 'd':
 654             if (program != AT)
 655                 usage();
 656
 657             program = ATRM;
 658             options = "V";
 659             break;
 660
 661         case 'l':
 662             if (program != AT)
 663                 usage();
 664
 665             program = ATQ;
 666             options = "q:vV";
 667             break;
 668
 669         case 'b':
 670             if (program != AT)
 671                 usage();
 672
 673             program = BATCH;
 674             options = "f:q:mvV";
 675             break;
 676
 677         case 'V':
 678             disp_version = 1;
 679             break;
 680
 681         case 'c':
 682             program = CAT;
 683             options = "";
 684             break;
 685
 686         default:
 687             usage();
 688             break;
 689         }
 690     /* end of options eating
 691      */
 692
 693     if (disp_version)
 694         fprintf(stderr, "at version " VERSION "\n"
 695                         "Bug reports to: ig25@rz.uni-karlsruhe.de (Thomas Koenig)\n");
 696
 697     /* select our program
 698      */
 699     if(!check_permission())
 700         errx(EXIT_FAILURE, "you do not have permission to use this program");
 701     switch (program) {
 702     case ATQ:
 703
 704         REDUCE_PRIV(DAEMON_UID, DAEMON_GID)
 705
 706         list_jobs();
 707         break;
 708
 709     case ATRM:
 710
 711         REDUCE_PRIV(DAEMON_UID, DAEMON_GID)
 712
 713         process_jobs(argc, argv, ATRM);
 714         break;
 715
 716     case CAT:
 717
 718         process_jobs(argc, argv, CAT);
 719         break;
 720
 721     case AT:
 722         timer = parsetime(argc, argv);
 723         if (atverify)
 724         {
 725             struct tm *tm = localtime(&timer);
 726             fprintf(stderr, "%s\n", asctime(tm));
 727         }
 728         writefile(timer, queue);
 729         break;
 730
 731     case BATCH:
 732         if (queue_set)
 733             queue = toupper(queue);
 734         else
 735             queue = DEFAULT_BATCH_QUEUE;
 736
 737         if (argc > optind)
 738             timer = parsetime(argc, argv);
 739         else
 740             timer = time(NULL);
 741
 742         if (atverify)
 743         {
 744             struct tm *tm = localtime(&timer);
 745             fprintf(stderr, "%s\n", asctime(tm));
 746         }
 747
 748         writefile(timer, queue);
 749         break;
 750
 751     default:
 752         panic("internal error");
 753         break;
 754     }
 755     exit(EXIT_SUCCESS);
 756 }