usr.sbin/cron/cron/database.c

   1 /* Copyright 1988,1990,1993,1994 by Paul Vixie
   2  * All rights reserved
   3  *
   4  * Distribute freely, except: don't remove my name from the source or
   5  * documentation (don't take credit for my work), mark your changes (don't
   6  * get me blamed for your possible bugs), don't alter or remove this
   7  * notice.  May be sold if buildable source is provided to buyer.  No
   8  * warrantee of any kind, express or implied, is included with this
   9  * software; use at your own risk, responsibility for damages (if any) to
  10  * anyone resulting from the use of this software rests entirely with the
  11  * user.
  12  *
  13  * Send bug reports, bug fixes, enhancements, requests, flames, etc., and
  14  * I'll try to keep a version up to date.  I can be reached as follows:
  15  * Paul Vixie          <paul@vix.com>          uunet!decwrl!vixie!paul
  16  */
  17
  18 #if !defined(lint) && !defined(LINT)
  19 static const char rcsid[] =
  20   "$FreeBSD$";
  21 #endif
  22
  23 /* vix 26jan87 [RCS has the log]
  24  */
  25
  26
  27 #include "cron.h"
  28 #include <fcntl.h>
  29 #include <sys/stat.h>
  30 #include <sys/file.h>
  31
  32
  33 #define TMAX(a,b) ((a)>(b)?(a):(b))
  34
  35
  36 static  void            process_crontab(char *, char *, char *,
  37                                              struct stat *,
  38                                              cron_db *, cron_db *);
  39
  40
  41 void
  42 load_database(old_db)
  43         cron_db         *old_db;
  44 {
  45         DIR             *dir;
  46         struct stat     statbuf;
  47         struct stat     syscron_stat, st;
  48         time_t          maxmtime;
  49         DIR_T           *dp;
  50         cron_db         new_db;
  51         user            *u, *nu;
  52         struct {
  53                 const char *name;
  54                 struct stat st;
  55         } syscrontabs [] = {
  56                 { SYSCRONTABS },
  57                 { LOCALSYSCRONTABS }
  58         };
  59         int i, ret;
  60
  61         Debug(DLOAD, ("[%d] load_database()\n", getpid()))
  62
  63         /* before we start loading any data, do a stat on SPOOL_DIR
  64          * so that if anything changes as of this moment (i.e., before we've
  65          * cached any of the database), we'll see the changes next time.
  66          */
  67         if (stat(SPOOL_DIR, &statbuf) < OK) {
  68                 log_it("CRON", getpid(), "STAT FAILED", SPOOL_DIR);
  69                 (void) exit(ERROR_EXIT);
  70         }
  71
  72         /* track system crontab file
  73          */
  74         if (stat(SYSCRONTAB, &syscron_stat) < OK)
  75                 syscron_stat.st_mtime = 0;
  76
  77         maxmtime = TMAX(statbuf.st_mtime, syscron_stat.st_mtime);
  78
  79         for (i = 0; i < nitems(syscrontabs); i++) {
  80                 if (stat(syscrontabs[i].name, &syscrontabs[i].st) != -1) {
  81                         maxmtime = TMAX(syscrontabs[i].st.st_mtime, maxmtime);
  82                         /* Traverse into directory */
  83                         if (!(dir = opendir(syscrontabs[i].name)))
  84                                 continue;
  85                         while (NULL != (dp = readdir(dir))) {
  86                                 if (dp->d_name[0] == '.')
  87                                         continue;
  88                                 ret = fstatat(dirfd(dir), dp->d_name, &st, 0);
  89                                 if (ret != 0 || !S_ISREG(st.st_mode))
  90                                         continue;
  91                                 maxmtime = TMAX(st.st_mtime, maxmtime);
  92                         }
  93                         closedir(dir);
  94                 } else {
  95                         syscrontabs[i].st.st_mtime = 0;
  96                 }
  97         }
  98
  99         /* if spooldir's mtime has not changed, we don't need to fiddle with
 100          * the database.
 101          *
 102          * Note that old_db->mtime is initialized to 0 in main(), and
 103          * so is guaranteed to be different than the stat() mtime the first
 104          * time this function is called.
 105          */
 106         if (old_db->mtime == maxmtime) {
 107                 Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n",
 108                               getpid()))
 109                 return;
 110         }
 111
 112         /* something's different.  make a new database, moving unchanged
 113          * elements from the old database, reloading elements that have
 114          * actually changed.  Whatever is left in the old database when
 115          * we're done is chaff -- crontabs that disappeared.
 116          */
 117         new_db.mtime = maxmtime;
 118         new_db.head = new_db.tail = NULL;
 119
 120         if (syscron_stat.st_mtime) {
 121                 process_crontab("root", SYS_NAME,
 122                                 SYSCRONTAB, &syscron_stat,
 123                                 &new_db, old_db);
 124         }
 125
 126         for (i = 0; i < nitems(syscrontabs); i++) {
 127                 char tabname[MAXPATHLEN];
 128                 if (syscrontabs[i].st.st_mtime == 0)
 129                         continue;
 130                 if (!(dir = opendir(syscrontabs[i].name))) {
 131                         log_it("CRON", getpid(), "OPENDIR FAILED",
 132                             syscrontabs[i].name);
 133                         (void) exit(ERROR_EXIT);
 134                 }
 135
 136                 while (NULL != (dp = readdir(dir))) {
 137                         if (dp->d_name[0] == '.')
 138                                 continue;
 139                         if (fstatat(dirfd(dir), dp->d_name, &st, 0) == 0 &&
 140                             !S_ISREG(st.st_mode))
 141                                 continue;
 142                         snprintf(tabname, sizeof(tabname), "%s/%s",
 143                             syscrontabs[i].name, dp->d_name);
 144                         process_crontab("root", SYS_NAME, tabname,
 145                             &syscrontabs[i].st, &new_db, old_db);
 146                 }
 147                 closedir(dir);
 148         }
 149
 150         /* we used to keep this dir open all the time, for the sake of
 151          * efficiency.  however, we need to close it in every fork, and
 152          * we fork a lot more often than the mtime of the dir changes.
 153          */
 154         if (!(dir = opendir(SPOOL_DIR))) {
 155                 log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR);
 156                 (void) exit(ERROR_EXIT);
 157         }
 158
 159         while (NULL != (dp = readdir(dir))) {
 160                 char    fname[MAXNAMLEN+1],
 161                         tabname[MAXNAMLEN+1];
 162
 163                 /* avoid file names beginning with ".".  this is good
 164                  * because we would otherwise waste two guaranteed calls
 165                  * to getpwnam() for . and .., and also because user names
 166                  * starting with a period are just too nasty to consider.
 167                  */
 168                 if (dp->d_name[0] == '.')
 169                         continue;
 170
 171                 (void) strncpy(fname, dp->d_name, sizeof(fname));
 172                 fname[sizeof(fname)-1] = '\0';
 173                 (void) snprintf(tabname, sizeof tabname, CRON_TAB(fname));
 174
 175                 process_crontab(fname, fname, tabname,
 176                                 &statbuf, &new_db, old_db);
 177         }
 178         closedir(dir);
 179
 180         /* if we don't do this, then when our children eventually call
 181          * getpwnam() in do_command.c's child_process to verify MAILTO=,
 182          * they will screw us up (and v-v).
 183          */
 184         endpwent();
 185
 186         /* whatever's left in the old database is now junk.
 187          */
 188         Debug(DLOAD, ("unlinking old database:\n"))
 189         for (u = old_db->head;  u != NULL;  u = nu) {
 190                 Debug(DLOAD, ("\t%s\n", u->name))
 191                 nu = u->next;
 192                 unlink_user(old_db, u);
 193                 free_user(u);
 194         }
 195
 196         /* overwrite the database control block with the new one.
 197          */
 198         *old_db = new_db;
 199         Debug(DLOAD, ("load_database is done\n"))
 200 }
 201
 202
 203 void
 204 link_user(db, u)
 205         cron_db *db;
 206         user    *u;
 207 {
 208         if (db->head == NULL)
 209                 db->head = u;
 210         if (db->tail)
 211                 db->tail->next = u;
 212         u->prev = db->tail;
 213         u->next = NULL;
 214         db->tail = u;
 215 }
 216
 217
 218 void
 219 unlink_user(db, u)
 220         cron_db *db;
 221         user    *u;
 222 {
 223         if (u->prev == NULL)
 224                 db->head = u->next;
 225         else
 226                 u->prev->next = u->next;
 227
 228         if (u->next == NULL)
 229                 db->tail = u->prev;
 230         else
 231                 u->next->prev = u->prev;
 232 }
 233
 234
 235 user *
 236 find_user(db, name)
 237         cron_db *db;
 238         char    *name;
 239 {
 240         char    *env_get();
 241         user    *u;
 242
 243         for (u = db->head;  u != NULL;  u = u->next)
 244                 if (!strcmp(u->name, name))
 245                         break;
 246         return u;
 247 }
 248
 249
 250 static void
 251 process_crontab(uname, fname, tabname, statbuf, new_db, old_db)
 252         char            *uname;
 253         char            *fname;
 254         char            *tabname;
 255         struct stat     *statbuf;
 256         cron_db         *new_db;
 257         cron_db         *old_db;
 258 {
 259         struct passwd   *pw = NULL;
 260         int             crontab_fd = OK - 1;
 261         user            *u;
 262         entry           *e;
 263         time_t          now;
 264
 265         if (strcmp(fname, SYS_NAME) && !(pw = getpwnam(uname))) {
 266                 /* file doesn't have a user in passwd file.
 267                  */
 268                 log_it(fname, getpid(), "ORPHAN", "no passwd entry");
 269                 goto next_crontab;
 270         }
 271
 272         if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK) {
 273                 /* crontab not accessible?
 274                  */
 275                 log_it(fname, getpid(), "CAN'T OPEN", tabname);
 276                 goto next_crontab;
 277         }
 278
 279         if (fstat(crontab_fd, statbuf) < OK) {
 280                 log_it(fname, getpid(), "FSTAT FAILED", tabname);
 281                 goto next_crontab;
 282         }
 283
 284         Debug(DLOAD, ("\t%s:", fname))
 285         u = find_user(old_db, fname);
 286         if (u != NULL) {
 287                 /* if crontab has not changed since we last read it
 288                  * in, then we can just use our existing entry.
 289                  */
 290                 if (u->mtime == statbuf->st_mtime) {
 291                         Debug(DLOAD, (" [no change, using old data]"))
 292                         unlink_user(old_db, u);
 293                         link_user(new_db, u);
 294                         goto next_crontab;
 295                 }
 296
 297                 /* before we fall through to the code that will reload
 298                  * the user, let's deallocate and unlink the user in
 299                  * the old database.  This is more a point of memory
 300                  * efficiency than anything else, since all leftover
 301                  * users will be deleted from the old database when
 302                  * we finish with the crontab...
 303                  */
 304                 Debug(DLOAD, (" [delete old data]"))
 305                 unlink_user(old_db, u);
 306                 free_user(u);
 307                 log_it(fname, getpid(), "RELOAD", tabname);
 308         }
 309         u = load_user(crontab_fd, pw, fname);
 310         if (u != NULL) {
 311                 u->mtime = statbuf->st_mtime;
 312                 /*
 313                  * TargetTime == 0 when we're initially populating the database,
 314                  * and TargetTime > 0 any time after that (i.e. we're reloading
 315                  * cron.d/ files because they've been created/modified).  In the
 316                  * latter case, we should check for any interval jobs and run
 317                  * them 'n' seconds from the time the job was loaded/reloaded.
 318                  * Otherwise, they will not be run until cron is restarted.
 319                  */
 320                 if (TargetTime != 0) {
 321                         now = time(NULL);
 322                         for (e = u->crontab; e != NULL; e = e->next) {
 323                                 if ((e->flags & INTERVAL) != 0)
 324                                         e->lastexit = now;
 325                         }
 326                 }
 327                 link_user(new_db, u);
 328         }
 329
 330 next_crontab:
 331         if (crontab_fd >= OK) {
 332                 Debug(DLOAD, (" [done]\n"))
 333                 close(crontab_fd);
 334         }
 335 }