database.c revision 320222
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) 19static const char rcsid[] = 20 "$FreeBSD: stable/10/usr.sbin/cron/cron/database.c 320222 2017-06-22 07:08:18Z ngie $"; 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 36static void process_crontab(char *, char *, char *, 37 struct stat *, 38 cron_db *, cron_db *); 39 40 41void 42load_database(old_db) 43 cron_db *old_db; 44{ 45 DIR *dir; 46 struct stat statbuf; 47 struct stat syscron_stat; 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; 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 } else { 83 syscrontabs[i].st.st_mtime = 0; 84 } 85 } 86 87 /* if spooldir's mtime has not changed, we don't need to fiddle with 88 * the database. 89 * 90 * Note that old_db->mtime is initialized to 0 in main(), and 91 * so is guaranteed to be different than the stat() mtime the first 92 * time this function is called. 93 */ 94 if (old_db->mtime == maxmtime) { 95 Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n", 96 getpid())) 97 return; 98 } 99 100 /* something's different. make a new database, moving unchanged 101 * elements from the old database, reloading elements that have 102 * actually changed. Whatever is left in the old database when 103 * we're done is chaff -- crontabs that disappeared. 104 */ 105 new_db.mtime = maxmtime; 106 new_db.head = new_db.tail = NULL; 107 108 if (syscron_stat.st_mtime) { 109 process_crontab("root", SYS_NAME, 110 SYSCRONTAB, &syscron_stat, 111 &new_db, old_db); 112 } 113 114 for (i = 0; i < nitems(syscrontabs); i++) { 115 char tabname[MAXPATHLEN]; 116 if (syscrontabs[i].st.st_mtime == 0) 117 continue; 118 if (!(dir = opendir(syscrontabs[i].name))) { 119 log_it("CRON", getpid(), "OPENDIR FAILED", 120 syscrontabs[i].name); 121 (void) exit(ERROR_EXIT); 122 } 123 124 while (NULL != (dp = readdir(dir))) { 125 if (dp->d_name[0] == '.') 126 continue; 127 if (dp->d_type != DT_REG) 128 continue; 129 snprintf(tabname, sizeof(tabname), "%s/%s", 130 syscrontabs[i].name, dp->d_name); 131 process_crontab("root", SYS_NAME, tabname, 132 &syscrontabs[i].st, &new_db, old_db); 133 } 134 closedir(dir); 135 } 136 137 /* we used to keep this dir open all the time, for the sake of 138 * efficiency. however, we need to close it in every fork, and 139 * we fork a lot more often than the mtime of the dir changes. 140 */ 141 if (!(dir = opendir(SPOOL_DIR))) { 142 log_it("CRON", getpid(), "OPENDIR FAILED", SPOOL_DIR); 143 (void) exit(ERROR_EXIT); 144 } 145 146 while (NULL != (dp = readdir(dir))) { 147 char fname[MAXNAMLEN+1], 148 tabname[MAXNAMLEN+1]; 149 150 /* avoid file names beginning with ".". this is good 151 * because we would otherwise waste two guaranteed calls 152 * to getpwnam() for . and .., and also because user names 153 * starting with a period are just too nasty to consider. 154 */ 155 if (dp->d_name[0] == '.') 156 continue; 157 158 (void) strncpy(fname, dp->d_name, sizeof(fname)); 159 fname[sizeof(fname)-1] = '\0'; 160 (void) snprintf(tabname, sizeof tabname, CRON_TAB(fname)); 161 162 process_crontab(fname, fname, tabname, 163 &statbuf, &new_db, old_db); 164 } 165 closedir(dir); 166 167 /* if we don't do this, then when our children eventually call 168 * getpwnam() in do_command.c's child_process to verify MAILTO=, 169 * they will screw us up (and v-v). 170 */ 171 endpwent(); 172 173 /* whatever's left in the old database is now junk. 174 */ 175 Debug(DLOAD, ("unlinking old database:\n")) 176 for (u = old_db->head; u != NULL; u = nu) { 177 Debug(DLOAD, ("\t%s\n", u->name)) 178 nu = u->next; 179 unlink_user(old_db, u); 180 free_user(u); 181 } 182 183 /* overwrite the database control block with the new one. 184 */ 185 *old_db = new_db; 186 Debug(DLOAD, ("load_database is done\n")) 187} 188 189 190void 191link_user(db, u) 192 cron_db *db; 193 user *u; 194{ 195 if (db->head == NULL) 196 db->head = u; 197 if (db->tail) 198 db->tail->next = u; 199 u->prev = db->tail; 200 u->next = NULL; 201 db->tail = u; 202} 203 204 205void 206unlink_user(db, u) 207 cron_db *db; 208 user *u; 209{ 210 if (u->prev == NULL) 211 db->head = u->next; 212 else 213 u->prev->next = u->next; 214 215 if (u->next == NULL) 216 db->tail = u->prev; 217 else 218 u->next->prev = u->prev; 219} 220 221 222user * 223find_user(db, name) 224 cron_db *db; 225 char *name; 226{ 227 char *env_get(); 228 user *u; 229 230 for (u = db->head; u != NULL; u = u->next) 231 if (!strcmp(u->name, name)) 232 break; 233 return u; 234} 235 236 237static void 238process_crontab(uname, fname, tabname, statbuf, new_db, old_db) 239 char *uname; 240 char *fname; 241 char *tabname; 242 struct stat *statbuf; 243 cron_db *new_db; 244 cron_db *old_db; 245{ 246 struct passwd *pw = NULL; 247 int crontab_fd = OK - 1; 248 user *u; 249 250 if (strcmp(fname, SYS_NAME) && !(pw = getpwnam(uname))) { 251 /* file doesn't have a user in passwd file. 252 */ 253 log_it(fname, getpid(), "ORPHAN", "no passwd entry"); 254 goto next_crontab; 255 } 256 257 if ((crontab_fd = open(tabname, O_RDONLY, 0)) < OK) { 258 /* crontab not accessible? 259 */ 260 log_it(fname, getpid(), "CAN'T OPEN", tabname); 261 goto next_crontab; 262 } 263 264 if (fstat(crontab_fd, statbuf) < OK) { 265 log_it(fname, getpid(), "FSTAT FAILED", tabname); 266 goto next_crontab; 267 } 268 269 Debug(DLOAD, ("\t%s:", fname)) 270 u = find_user(old_db, fname); 271 if (u != NULL) { 272 /* if crontab has not changed since we last read it 273 * in, then we can just use our existing entry. 274 */ 275 if (u->mtime == statbuf->st_mtime) { 276 Debug(DLOAD, (" [no change, using old data]")) 277 unlink_user(old_db, u); 278 link_user(new_db, u); 279 goto next_crontab; 280 } 281 282 /* before we fall through to the code that will reload 283 * the user, let's deallocate and unlink the user in 284 * the old database. This is more a point of memory 285 * efficiency than anything else, since all leftover 286 * users will be deleted from the old database when 287 * we finish with the crontab... 288 */ 289 Debug(DLOAD, (" [delete old data]")) 290 unlink_user(old_db, u); 291 free_user(u); 292 log_it(fname, getpid(), "RELOAD", tabname); 293 } 294 u = load_user(crontab_fd, pw, fname); 295 if (u != NULL) { 296 u->mtime = statbuf->st_mtime; 297 link_user(new_db, u); 298 } 299 300next_crontab: 301 if (crontab_fd >= OK) { 302 Debug(DLOAD, (" [done]\n")) 303 close(crontab_fd); 304 } 305} 306