575 lines
12 KiB
C
575 lines
12 KiB
C
/* Copyright 1988,1990,1993,1994 by Paul Vixie
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* All rights reserved
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*
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* Distribute freely, except: don't remove my name from the source or
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* documentation (don't take credit for my work), mark your changes (don't
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* get me blamed for your possible bugs), don't alter or remove this
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* notice. May be sold if buildable source is provided to buyer. No
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* warrantee of any kind, express or implied, is included with this
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* software; use at your own risk, responsibility for damages (if any) to
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* anyone resulting from the use of this software rests entirely with the
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* user.
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*
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* Send bug reports, bug fixes, enhancements, requests, flames, etc., and
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* I'll try to keep a version up to date. I can be reached as follows:
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* Paul Vixie <paul@vix.com> uunet!decwrl!vixie!paul
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*/
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#if !defined(lint) && !defined(LINT)
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static char rcsid[] = "$Id: crontab.c,v 1.1.1.3 1994/01/12 18:37:20 jtc Exp $";
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#endif
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/* crontab - install and manage per-user crontab files
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* vix 02may87 [RCS has the rest of the log]
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* vix 26jan87 [original]
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*/
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#define MAIN_PROGRAM
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#include "cron.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/file.h>
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#include <sys/stat.h>
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#ifdef USE_UTIMES
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# include <sys/time.h>
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#else
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# include <time.h>
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# include <utime.h>
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#endif
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#if defined(POSIX)
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# include <locale.h>
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#endif
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static PID_T 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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static struct passwd *pw;
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static void list_cmd __P((void)),
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delete_cmd __P((void)),
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edit_cmd __P((void)),
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replace_cmd __P((void)),
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poke_daemon __P((void)),
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check_error __P((char *)),
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parse_args __P((int c, char *v[]));
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#define NHEADER_LINES 3
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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(msg)
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char *msg;
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{
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fprintf(stderr, "%s: usage error: %s\n", ProgramName, msg);
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fprintf(stderr, "usage:\t%s [-u user] file\n", ProgramName);
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fprintf(stderr, "\t%s [-u user] { -e | -l | -r }\n", ProgramName);
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fprintf(stderr, "\t\t(default operation is replace, per 1003.2)\n");
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fprintf(stderr, "\t-e\t(edit user's crontab)\n");
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fprintf(stderr, "\t-l\t(list user's crontab)\n");
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fprintf(stderr, "\t-r\t(delete user's crontab)\n");
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exit(ERROR_EXIT);
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}
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int
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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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Pid = getpid();
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ProgramName = argv[0];
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#if defined(POSIX)
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setlocale(LC_ALL, "");
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#endif
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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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exit(0);
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/*NOTREACHED*/
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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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int argch;
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if (!(pw = getpwuid(getuid()))) {
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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:lerx:"))) {
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switch (argch) {
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case 'x':
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if (!set_debug_flags(optarg))
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usage("bad debug option");
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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 (!(pw = 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("only one operation permitted");
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Option = opt_list;
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break;
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case 'r':
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if (Option != opt_unknown)
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usage("only one operation permitted");
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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("only one operation permitted");
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Option = opt_edit;
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break;
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default:
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usage("unrecognized option");
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}
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}
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endpwent();
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if (Option != opt_unknown) {
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if (argv[optind] != NULL) {
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usage("no arguments permitted after this option");
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}
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} else {
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if (argv[optind] != NULL) {
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Option = opt_replace;
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(void) strcpy (Filename, argv[optind]);
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} else {
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usage("file name must be specified for replace");
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}
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}
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if (Option == opt_replace) {
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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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/* relinquish the setuid status of the binary during
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* the open, lest nonroot users read files they should
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* not be able to read. we can't use access() here
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* since there's a race condition. thanks go out to
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* Arnt Gulbrandsen <agulbra@pvv.unit.no> for spotting
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* the race.
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*/
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if (swap_uids() < OK) {
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perror("swapping uids");
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exit(ERROR_EXIT);
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}
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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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if (swap_uids() < OK) {
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perror("swapping uids back");
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exit(ERROR_EXIT);
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}
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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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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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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
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delete_cmd() {
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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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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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char n[MAX_FNAME], *editor;
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FILE *f;
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int ch, t, x;
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struct stat statbuf;
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time_t mtime;
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WAIT_T waiter;
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PID_T pid, xpid;
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log_it(RealUser, Pid, "BEGIN EDIT", User);
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NewCrontab = NULL;
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(void) sprintf(n, CRON_TAB(User));
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if (!(f = fopen(n, "r"))) {
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if (errno != ENOENT) {
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perror(n);
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exit(ERROR_EXIT);
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}
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fprintf(stderr, "no crontab for %s - using an empty one\n",
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User);
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if (!(f = fopen("/dev/null", "r"))) {
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perror("/dev/null");
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exit(ERROR_EXIT);
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}
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}
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(void) sprintf(Filename, "/tmp/crontab.%d", Pid);
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if (-1 == (t = open(Filename, O_CREAT|O_EXCL|O_RDWR, 0700))) {
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perror(Filename);
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goto fatal;
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}
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#ifdef HAS_FCHOWN
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if (fchown(t, getuid(), getgid()) < 0) {
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#else
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if (chown(Filename, getuid(), getgid()) < 0) {
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#endif
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perror("fchown");
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goto fatal;
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}
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if (!(NewCrontab = fdopen(t, "r+"))) {
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perror("fdopen");
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goto fatal;
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}
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Set_LineNum(1)
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/* ignore the top few comments since we probably put them there.
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*/
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for (x = 0; x < NHEADER_LINES; x++) {
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ch = get_char(f);
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if (EOF == ch)
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break;
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if ('#' != ch) {
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putc(ch, NewCrontab);
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break;
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}
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while (EOF != (ch = get_char(f)))
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if (ch == '\n')
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break;
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if (EOF == ch)
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break;
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}
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/* copy the rest of the crontab (if any) to the temp file.
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*/
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if (EOF != ch)
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while (EOF != (ch = get_char(f)))
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putc(ch, NewCrontab);
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fclose(f);
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fflush(NewCrontab); rewind(NewCrontab);
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if (ferror(NewCrontab)) {
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fprintf(stderr, "%s: error while writing new crontab to %s\n",
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ProgramName, Filename);
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fatal: if (NewCrontab) fclose(NewCrontab);
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unlink(Filename);
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exit(ERROR_EXIT);
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}
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if (fstat(t, &statbuf) < 0) {
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perror("fstat");
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goto fatal;
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}
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mtime = statbuf.st_mtime;
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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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/* we still have the file open. editors will generally rewrite the
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* original file rather than renaming/unlinking it and starting a
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* new one; even backup files are supposed to be made by copying
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* rather than by renaming. if some editor does not support this,
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* then don't use it. the security problems are more severe if we
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* close and reopen the file around the edit.
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*/
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switch (pid = fork()) {
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case -1:
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perror("fork");
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goto fatal;
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case 0:
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/* child */
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if (setuid(getuid()) < 0) {
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perror("setuid(getuid())");
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exit(ERROR_EXIT);
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}
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if (chdir("/tmp") < 0) {
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perror("chdir(/tmp)");
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exit(ERROR_EXIT);
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}
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execlp(editor, editor, Filename, NULL);
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perror(editor);
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exit(ERROR_EXIT);
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/*NOTREACHED*/
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default:
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/* parent */
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break;
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}
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/* parent */
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xpid = wait(&waiter);
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if (xpid != pid) {
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fprintf(stderr, "%s: wrong PID (%d != %d) from \"%s\"\n",
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ProgramName, xpid, pid, editor);
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goto fatal;
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}
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if (WIFEXITED(waiter) && WEXITSTATUS(waiter)) {
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fprintf(stderr, "%s: \"%s\" exited with status %d\n",
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ProgramName, editor, WEXITSTATUS(waiter));
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goto fatal;
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}
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if (WIFSIGNALED(waiter)) {
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fprintf(stderr,
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"%s: \"%s\" killed; signal %d (%score dumped)\n",
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ProgramName, editor, WTERMSIG(waiter),
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WCOREDUMP(waiter) ?"" :"no ");
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goto fatal;
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}
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if (fstat(t, &statbuf) < 0) {
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perror("fstat");
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goto fatal;
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}
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if (mtime == statbuf.st_mtime) {
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fprintf(stderr, "%s: no changes made to crontab\n",
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ProgramName);
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} else {
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fprintf(stderr, "%s: installing new crontab\n",
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ProgramName);
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replace_cmd();
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}
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fclose(NewCrontab); unlink(Filename);
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log_it(RealUser, Pid, "END EDIT", User);
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}
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static void
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replace_cmd() {
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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, eof;
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entry *e;
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time_t now = time(NULL);
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char **envp = env_init();
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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.
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*
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* VERY IMPORTANT: make sure NHEADER_LINES agrees with this code.
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*/
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fprintf(tmp, "# DO NOT EDIT THIS FILE - edit the master and reinstall.\n");
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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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ftruncate(fileno(tmp), ftell(tmp));
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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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Set_LineNum(1)
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CheckErrorCount = 0; eof = FALSE;
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while (!CheckErrorCount && !eof) {
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switch (load_env(envstr, tmp)) {
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case ERR:
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eof = TRUE;
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break;
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case FALSE:
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e = load_entry(tmp, check_error, pw, envp);
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if (e) free(e);
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break;
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case TRUE:
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break;
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}
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}
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if (CheckErrorCount != 0) {
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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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#ifdef HAS_FCHOWN
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if (fchown(fileno(tmp), ROOT_UID, -1) < OK) {
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#else
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if (chown(tn, ROOT_UID, -1) < OK) {
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#endif
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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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#ifdef HAS_FCHMOD
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if (fchmod(fileno(tmp), 0600) < OK) {
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#else
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if (chmod(tn, 0600) < OK) {
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#endif
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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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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);
|
|
|
|
poke_daemon();
|
|
}
|
|
|
|
|
|
static void
|
|
poke_daemon() {
|
|
#ifdef USE_UTIMES
|
|
struct timeval tvs[2];
|
|
struct timezone tz;
|
|
|
|
(void) gettimeofday(&tvs[0], &tz);
|
|
tvs[1] = tvs[0];
|
|
if (utimes(SPOOL_DIR, tvs) < OK) {
|
|
fprintf(stderr, "crontab: can't update mtime on spooldir\n");
|
|
perror(SPOOL_DIR);
|
|
return;
|
|
}
|
|
#else
|
|
if (utime(SPOOL_DIR, NULL) < OK) {
|
|
fprintf(stderr, "crontab: can't update mtime on spooldir\n");
|
|
perror(SPOOL_DIR);
|
|
return;
|
|
}
|
|
#endif /*USE_UTIMES*/
|
|
}
|