480 lines
9.2 KiB
C
480 lines
9.2 KiB
C
#ifndef lint
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static char rcsid[] = "$Id: crontab.c,v 1.8 1993/12/25 02:54:36 deraadt Exp $";
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#endif /* not lint */
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#define MAIN_PROGRAM
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#include "cron.h"
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#include <pwd.h>
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#include <errno.h>
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#include <sys/file.h>
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#if defined(BSD)
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# include <sys/time.h>
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#endif /*BSD*/
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static int Pid;
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static char User[MAX_UNAME], RealUser[MAX_UNAME];
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static char Filename[MAX_FNAME];
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static FILE *NewCrontab;
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static int CheckErrorCount;
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static enum {opt_unknown, opt_list, opt_delete, opt_edit, opt_replace}
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Option;
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extern char *getenv(), *strcpy();
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extern int getuid();
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extern struct passwd *getpwnam();
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extern int getopt(), optind;
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extern char *optarg;
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extern void log_it(); /* misc.c */
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#if DEBUGGING
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static char *Options[] = {"???", "list", "delete", "edit", "replace"};
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#endif
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static void
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usage()
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{
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fprintf(stderr, "usage: %s [-u user] ...\n", ProgramName);
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fprintf(stderr, " ... -l (list user's crontab)\n");
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fprintf(stderr, " ... -d (delete user's crontab)\n");
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fprintf(stderr, " ... -e (edit user's crontab)\n");
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fprintf(stderr, " ... -r file (replace user's crontab)\n");
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exit(ERROR_EXIT);
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}
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static void parse_args(), list_cmd(), delete_cmd(), edit_cmd(), replace_cmd();
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main(argc, argv)
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int argc;
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char *argv[];
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{
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void set_cron_uid(), set_cron_cwd();
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Pid = getpid();
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ProgramName = argv[0];
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#if defined(BSD)
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setlinebuf(stderr);
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#endif
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parse_args(argc, argv); /* sets many globals, opens a file */
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set_cron_uid();
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set_cron_cwd();
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if (!allowed(User)) {
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fprintf(stderr,
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"You (%s) are not allowed to use this program (%s)\n",
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User, ProgramName);
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fprintf(stderr, "See crontab(1) for more information\n");
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log_it(RealUser, Pid, "AUTH", "crontab command not allowed");
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exit(ERROR_EXIT);
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}
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switch (Option)
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{
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case opt_list: list_cmd();
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break;
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case opt_delete: delete_cmd();
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break;
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case opt_edit: edit_cmd();
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break;
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case opt_replace: replace_cmd();
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break;
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}
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}
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static void
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parse_args(argc, argv)
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int argc;
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char *argv[];
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{
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void usage();
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struct passwd *pw;
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int argch;
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if (!(pw = getpwuid(getuid())))
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{
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fprintf(stderr, "%s: your UID isn't in the passwd file.\n",
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ProgramName);
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fprintf(stderr, "bailing out.\n");
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exit(ERROR_EXIT);
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}
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strcpy(User, pw->pw_name);
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strcpy(RealUser, User);
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Filename[0] = '\0';
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Option = opt_unknown;
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while (EOF != (argch = getopt(argc, argv, "u:lder:x:")))
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{
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switch (argch)
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{
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case 'x':
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if (!set_debug_flags(optarg))
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usage();
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break;
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case 'u':
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if (getuid() != ROOT_UID)
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{
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fprintf(stderr,
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"must be privileged to use -u\n");
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exit(ERROR_EXIT);
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}
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if ((struct passwd *)NULL == getpwnam(optarg))
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{
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fprintf(stderr, "%s: user `%s' unknown\n",
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ProgramName, optarg);
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exit(ERROR_EXIT);
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}
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(void) strcpy(User, optarg);
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break;
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case 'l':
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if (Option != opt_unknown)
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usage();
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Option = opt_list;
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break;
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case 'd':
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if (Option != opt_unknown)
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usage();
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Option = opt_delete;
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break;
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case 'e':
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if (Option != opt_unknown)
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usage();
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Option = opt_edit;
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break;
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case 'r':
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if (Option != opt_unknown)
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usage();
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Option = opt_replace;
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(void) strcpy(Filename, optarg);
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break;
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default:
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usage();
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}
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}
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endpwent();
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if (Option == opt_unknown || argv[optind] != NULL)
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usage();
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if (Option == opt_replace) {
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if (!Filename[0]) {
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/* getopt(3) says this can't be true
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* but I'm feeling extra paranoid today.
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*/
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fprintf(stderr, "filename must be given for -r\n");
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usage();
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}
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/* we have to open the file here because we're going to
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* chdir(2) into /var/cron before we get around to
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* reading the file.
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*/
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if (!strcmp(Filename, "-")) {
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NewCrontab = stdin;
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} else {
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/* swap effective/real uid to plug security hole */
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setreuid(geteuid(), getuid());
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if (!(NewCrontab = fopen(Filename, "r"))) {
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perror(Filename);
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exit(ERROR_EXIT);
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}
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setreuid(geteuid(), getuid());
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}
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}
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Debug(DMISC, ("user=%s, file=%s, option=%s\n",
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User, Filename, Options[(int)Option]))
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}
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static void
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list_cmd()
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{
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char n[MAX_FNAME];
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FILE *f;
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int ch;
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log_it(RealUser, Pid, "LIST", User);
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(void) sprintf(n, CRON_TAB(User));
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if (!(f = fopen(n, "r")))
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{
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if (errno == ENOENT)
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fprintf(stderr, "no crontab for %s\n", User);
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else
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perror(n);
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exit(ERROR_EXIT);
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}
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/* file is open. copy to stdout, close.
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*/
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Set_LineNum(1)
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while (EOF != (ch = get_char(f)))
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putchar(ch);
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fclose(f);
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}
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static void poke_daemon();
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static void
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delete_cmd()
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{
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extern errno;
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int unlink();
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char n[MAX_FNAME];
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log_it(RealUser, Pid, "DELETE", User);
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(void) sprintf(n, CRON_TAB(User));
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if (unlink(n))
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{
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if (errno == ENOENT)
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fprintf(stderr, "no crontab for %s\n", User);
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else
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perror(n);
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exit(ERROR_EXIT);
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}
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poke_daemon();
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}
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static void
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check_error(msg)
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char *msg;
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{
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CheckErrorCount += 1;
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fprintf(stderr, "\"%s\", line %d: %s\n", Filename, LineNumber, msg);
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}
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static void
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edit_cmd()
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{
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char n[MAX_FNAME], tn[MAX_FNAME], *editor;
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FILE *f, *tf;
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int ch, t, pid;
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struct stat before, after;
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log_it(RealUser, Pid, "BEGIN EDIT", User);
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(void) sprintf(n, CRON_TAB(User));
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if (!(f = fopen(n, "r")))
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{
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if (errno == ENOENT)
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fprintf(stderr, "no crontab for %s\n", User);
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else
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perror(n);
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exit(ERROR_EXIT);
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}
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(void) sprintf(tn, "/tmp/crontab.%d", getpid());
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if (-1 == (t = open(tn, O_CREAT|O_RDWR, 0600))) {
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perror(tn);
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exit(ERROR_EXIT);
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}
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if (fchown(t, getuid(), -1) < OK)
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{
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perror("chown");
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goto fatal;
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}
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if (!(tf = fdopen(t, "r+"))) {
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perror("fdopen");
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goto fatal;
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}
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/* copy the crontab to the temp file. skip top two comments since we
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* added them during the 'replace'.
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*/
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Set_LineNum(1)
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t = 0;
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while (EOF != (ch = get_char(f))) {
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if (t < 2) {
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t += (ch == '\n');
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} else {
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putc(ch, tf);
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}
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}
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fflush(tf); rewind(tf);
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fclose(f);
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if (ferror(tf)) {
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fprintf(stderr, "%s: error while writing new crontab to %s\n",
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ProgramName, tn);
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fclose(tf);
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fatal:
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unlink(tn);
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exit(ERROR_EXIT);
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}
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if ((!(editor = getenv("VISUAL")))
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&& (!(editor = getenv("EDITOR")))
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) {
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editor = EDITOR;
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}
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(void) fstat(fileno(tf), &before);
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fclose(tf);
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pid = VFORK();
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if (pid < 0) {
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perror("fork");
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goto fatal;
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}
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if (pid == 0) {
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char *argv[3];
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/* CHILD */
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setuid(getuid()); /* give up euid which is root */
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argv[0] = editor;
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argv[1] = tn;
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argv[2] = NULL;
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fprintf(stderr, "[%s %s]\n", editor, tn);
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execvp(editor, argv);
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perror(editor);
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exit(ERROR_EXIT);
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}
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(void) wait((int *)0);
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if (!(tf = fopen(tn, "r"))) {
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perror(tn);
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goto fatal;
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}
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(void) fstat(fileno(tf), &after);
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if (after.st_mtime == before.st_mtime) {
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fprintf(stderr, "[no changes were made to the crontab]\n");
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fclose(tf);
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} else {
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fprintf(stderr, "[new crontab now being installed]\n");
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NewCrontab = tf;
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replace_cmd(); /* closes NewCrontab */
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}
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unlink(tn);
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}
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static void
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replace_cmd()
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{
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entry *load_entry();
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int load_env();
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int unlink();
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void free_entry();
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void check_error();
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void poke_daemon();
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extern errno;
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char n[MAX_FNAME], envstr[MAX_ENVSTR], tn[MAX_FNAME];
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FILE *tmp;
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int ch;
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entry *e;
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int status;
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time_t now = time(NULL);
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(void) sprintf(n, "tmp.%d", Pid);
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(void) sprintf(tn, CRON_TAB(n));
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if (!(tmp = fopen(tn, "w"))) {
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perror(tn);
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exit(ERROR_EXIT);
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}
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/* write a signature at the top of the file. for brian.
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*/
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fprintf(tmp, "# (%s installed on %-24.24s)\n", Filename, ctime(&now));
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fprintf(tmp, "# (Cron version -- %s)\n", rcsid);
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/* copy the crontab to the tmp
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*/
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Set_LineNum(1)
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while (EOF != (ch = get_char(NewCrontab)))
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putc(ch, tmp);
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fclose(NewCrontab);
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fflush(tmp); rewind(tmp);
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if (ferror(tmp)) {
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fprintf(stderr, "%s: error while writing new crontab to %s\n",
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ProgramName, tn);
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fclose(tmp); unlink(tn);
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exit(ERROR_EXIT);
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}
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/* check the syntax of the file being installed.
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*/
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/* BUG: was reporting errors after the EOF if there were any errors
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* in the file proper -- kludged it by stopping after first error.
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* vix 31mar87
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*/
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CheckErrorCount = 0;
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while (!CheckErrorCount && (status = load_env(envstr, tmp)) >= OK)
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{
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if (status == FALSE)
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{
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if (NULL != (e = load_entry(NewCrontab, check_error)))
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free((char *) e);
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}
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}
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if (CheckErrorCount != 0)
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{
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fprintf(stderr, "errors in crontab file, can't install.\n");
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fclose(tmp); unlink(tn);
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exit(ERROR_EXIT);
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}
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if (fchown(fileno(tmp), ROOT_UID, -1) < OK)
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{
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perror("chown");
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fclose(tmp); unlink(tn);
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exit(ERROR_EXIT);
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}
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if (fchmod(fileno(tmp), 0600) < OK)
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{
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perror("chown");
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fclose(tmp); unlink(tn);
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exit(ERROR_EXIT);
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}
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if (fclose(tmp) == EOF) {
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perror("fclose");
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unlink(tn);
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exit(ERROR_EXIT);
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}
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(void) sprintf(n, CRON_TAB(User));
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if (rename(tn, n))
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{
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fprintf(stderr, "%s: error renaming %s to %s\n",
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ProgramName, tn, n);
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perror("rename");
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unlink(tn);
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exit(ERROR_EXIT);
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}
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log_it(RealUser, Pid, "REPLACE", User);
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poke_daemon();
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}
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static void
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poke_daemon()
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{
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#if defined(BSD)
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struct timeval tvs[2];
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struct timezone tz;
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(void) gettimeofday(&tvs[0], &tz);
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tvs[1] = tvs[0];
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if (utimes(SPOOL_DIR, tvs) < OK)
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{
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fprintf(stderr, "crontab: can't update mtime on spooldir\n");
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perror(SPOOL_DIR);
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return;
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}
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#endif /*BSD*/
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#if defined(ATT)
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if (utime(SPOOL_DIR, NULL) < OK)
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{
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fprintf(stderr, "crontab: can't update mtime on spooldir\n");
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perror(SPOOL_DIR);
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return;
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}
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#endif /*ATT*/
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}
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