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freebsd/usr.bin/at/at.c
Pietro Cerutti 1a47f28b71 - Do not bail out if stat(2) fails with ENOENT in the spool directory. This 
happens if another atrm process removes a job while we're scanning through
  the directory.
- While at it, optimize a bit the directory scanning, so that we quit looping
  as soon as all jobs specified in argv have been dealt with.

Approved by:	cognet
2013-04-12 14:32:16 +00:00

915 lines
20 KiB
C
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/*
* at.c : Put file into atrun queue
* Copyright (C) 1993, 1994 Thomas Koenig
*
* Atrun & Atq modifications
* Copyright (C) 1993 David Parsons
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. The name of the author(s) may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#define _USE_BSD 1
/* System Headers */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <ctype.h>
#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#ifndef __FreeBSD__
#include <getopt.h>
#endif
#ifdef __FreeBSD__
#include <locale.h>
#endif
#include <pwd.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
/* Local headers */
#include "at.h"
#include "panic.h"
#include "parsetime.h"
#include "perm.h"
#define MAIN
#include "privs.h"
/* Macros */
#ifndef ATJOB_DIR
#define ATJOB_DIR "/usr/spool/atjobs/"
#endif
#ifndef LFILE
#define LFILE ATJOB_DIR ".lockfile"
#endif
#ifndef ATJOB_MX
#define ATJOB_MX 255
#endif
#define ALARMC 10 /* Number of seconds to wait for timeout */
#define SIZE 255
#define TIMESIZE 50
enum { ATQ, ATRM, AT, BATCH, CAT }; /* what program we want to run */
/* File scope variables */
static const char *no_export[] = {
"TERM", "TERMCAP", "DISPLAY", "_"
};
static int send_mail = 0;
static char *atinput = NULL; /* where to get input from */
static char atqueue = 0; /* which queue to examine for jobs (atq) */
/* External variables */
extern char **environ;
int fcreated;
char atfile[] = ATJOB_DIR "12345678901234";
char atverify = 0; /* verify time instead of queuing job */
char *namep;
/* Function declarations */
static void sigc(int signo);
static void alarmc(int signo);
static char *cwdname(void);
static void writefile(time_t runtimer, char queue);
static void list_jobs(long *, int);
static long nextjob(void);
static time_t ttime(const char *arg);
static int in_job_list(long, long *, int);
static long *get_job_list(int, char *[], int *);
/* Signal catching functions */
static void sigc(int signo __unused)
{
/* If the user presses ^C, remove the spool file and exit
*/
if (fcreated)
{
PRIV_START
unlink(atfile);
PRIV_END
}
_exit(EXIT_FAILURE);
}
static void alarmc(int signo __unused)
{
char buf[1024];
/* Time out after some seconds. */
strlcpy(buf, namep, sizeof(buf));
strlcat(buf, ": file locking timed out\n", sizeof(buf));
write(STDERR_FILENO, buf, strlen(buf));
sigc(0);
}
/* Local functions */
static char *cwdname(void)
{
/* Read in the current directory; the name will be overwritten on
* subsequent calls.
*/
static char *ptr = NULL;
static size_t size = SIZE;
if (ptr == NULL)
if ((ptr = malloc(size)) == NULL)
errx(EXIT_FAILURE, "virtual memory exhausted");
while (1)
{
if (ptr == NULL)
panic("out of memory");
if (getcwd(ptr, size-1) != NULL)
return ptr;
if (errno != ERANGE)
perr("cannot get directory");
free (ptr);
size += SIZE;
if ((ptr = malloc(size)) == NULL)
errx(EXIT_FAILURE, "virtual memory exhausted");
}
}
static long
nextjob(void)
{
long jobno;
FILE *fid;
if ((fid = fopen(ATJOB_DIR ".SEQ", "r+")) != NULL) {
if (fscanf(fid, "%5lx", &jobno) == 1) {
rewind(fid);
jobno = (1+jobno) % 0xfffff; /* 2^20 jobs enough? */
fprintf(fid, "%05lx\n", jobno);
}
else
jobno = EOF;
fclose(fid);
return jobno;
}
else if ((fid = fopen(ATJOB_DIR ".SEQ", "w")) != NULL) {
fprintf(fid, "%05lx\n", jobno = 1);
fclose(fid);
return 1;
}
return EOF;
}
static void
writefile(time_t runtimer, char queue)
{
/* This does most of the work if at or batch are invoked for writing a job.
*/
long jobno;
char *ap, *ppos, *mailname;
struct passwd *pass_entry;
struct stat statbuf;
int fdes, lockdes, fd2;
FILE *fp, *fpin;
struct sigaction act;
char **atenv;
int ch;
mode_t cmask;
struct flock lock;
#ifdef __FreeBSD__
(void) setlocale(LC_TIME, "");
#endif
/* Install the signal handler for SIGINT; terminate after removing the
* spool file if necessary
*/
act.sa_handler = sigc;
sigemptyset(&(act.sa_mask));
act.sa_flags = 0;
sigaction(SIGINT, &act, NULL);
ppos = atfile + strlen(ATJOB_DIR);
/* Loop over all possible file names for running something at this
* particular time, see if a file is there; the first empty slot at any
* particular time is used. Lock the file LFILE first to make sure
* we're alone when doing this.
*/
PRIV_START
if ((lockdes = open(LFILE, O_WRONLY | O_CREAT, S_IWUSR | S_IRUSR)) < 0)
perr("cannot open lockfile " LFILE);
lock.l_type = F_WRLCK; lock.l_whence = SEEK_SET; lock.l_start = 0;
lock.l_len = 0;
act.sa_handler = alarmc;
sigemptyset(&(act.sa_mask));
act.sa_flags = 0;
/* Set an alarm so a timeout occurs after ALARMC seconds, in case
* something is seriously broken.
*/
sigaction(SIGALRM, &act, NULL);
alarm(ALARMC);
fcntl(lockdes, F_SETLKW, &lock);
alarm(0);
if ((jobno = nextjob()) == EOF)
perr("cannot generate job number");
sprintf(ppos, "%c%5lx%8lx", queue,
jobno, (unsigned long) (runtimer/60));
for(ap=ppos; *ap != '\0'; ap ++)
if (*ap == ' ')
*ap = '0';
if (stat(atfile, &statbuf) != 0)
if (errno != ENOENT)
perr("cannot access " ATJOB_DIR);
/* Create the file. The x bit is only going to be set after it has
* been completely written out, to make sure it is not executed in the
* meantime. To make sure they do not get deleted, turn off their r
* bit. Yes, this is a kluge.
*/
cmask = umask(S_IRUSR | S_IWUSR | S_IXUSR);
if ((fdes = creat(atfile, O_WRONLY)) == -1)
perr("cannot create atjob file");
if ((fd2 = dup(fdes)) <0)
perr("error in dup() of job file");
if(fchown(fd2, real_uid, real_gid) != 0)
perr("cannot give away file");
PRIV_END
/* We no longer need suid root; now we just need to be able to write
* to the directory, if necessary.
*/
REDUCE_PRIV(DAEMON_UID, DAEMON_GID)
/* We've successfully created the file; let's set the flag so it
* gets removed in case of an interrupt or error.
*/
fcreated = 1;
/* Now we can release the lock, so other people can access it
*/
lock.l_type = F_UNLCK; lock.l_whence = SEEK_SET; lock.l_start = 0;
lock.l_len = 0;
fcntl(lockdes, F_SETLKW, &lock);
close(lockdes);
if((fp = fdopen(fdes, "w")) == NULL)
panic("cannot reopen atjob file");
/* Get the userid to mail to, first by trying getlogin(),
* then from LOGNAME, finally from getpwuid().
*/
mailname = getlogin();
if (mailname == NULL)
mailname = getenv("LOGNAME");
if ((mailname == NULL) || (mailname[0] == '\0')
|| (strlen(mailname) >= MAXLOGNAME) || (getpwnam(mailname)==NULL))
{
pass_entry = getpwuid(real_uid);
if (pass_entry != NULL)
mailname = pass_entry->pw_name;
}
if (atinput != (char *) NULL)
{
fpin = freopen(atinput, "r", stdin);
if (fpin == NULL)
perr("cannot open input file");
}
fprintf(fp, "#!/bin/sh\n# atrun uid=%ld gid=%ld\n# mail %*s %d\n",
(long) real_uid, (long) real_gid, MAXLOGNAME - 1, mailname,
send_mail);
/* Write out the umask at the time of invocation
*/
fprintf(fp, "umask %lo\n", (unsigned long) cmask);
/* Write out the environment. Anything that may look like a
* special character to the shell is quoted, except for \n, which is
* done with a pair of "'s. Don't export the no_export list (such
* as TERM or DISPLAY) because we don't want these.
*/
for (atenv= environ; *atenv != NULL; atenv++)
{
int export = 1;
char *eqp;
eqp = strchr(*atenv, '=');
if (ap == NULL)
eqp = *atenv;
else
{
size_t i;
for (i=0; i<sizeof(no_export)/sizeof(no_export[0]); i++)
{
export = export
&& (strncmp(*atenv, no_export[i],
(size_t) (eqp-*atenv)) != 0);
}
eqp++;
}
if (export)
{
fwrite(*atenv, sizeof(char), eqp-*atenv, fp);
for(ap = eqp;*ap != '\0'; ap++)
{
if (*ap == '\n')
fprintf(fp, "\"\n\"");
else
{
if (!isalnum(*ap)) {
switch (*ap) {
case '%': case '/': case '{': case '[':
case ']': case '=': case '}': case '@':
case '+': case '#': case ',': case '.':
case ':': case '-': case '_':
break;
default:
fputc('\\', fp);
break;
}
}
fputc(*ap, fp);
}
}
fputs("; export ", fp);
fwrite(*atenv, sizeof(char), eqp-*atenv -1, fp);
fputc('\n', fp);
}
}
/* Cd to the directory at the time and write out all the
* commands the user supplies from stdin.
*/
fprintf(fp, "cd ");
for (ap = cwdname(); *ap != '\0'; ap++)
{
if (*ap == '\n')
fprintf(fp, "\"\n\"");
else
{
if (*ap != '/' && !isalnum(*ap))
fputc('\\', fp);
fputc(*ap, fp);
}
}
/* Test cd's exit status: die if the original directory has been
* removed, become unreadable or whatever
*/
fprintf(fp, " || {\n\t echo 'Execution directory "
"inaccessible' >&2\n\t exit 1\n}\n");
while((ch = getchar()) != EOF)
fputc(ch, fp);
fprintf(fp, "\n");
if (ferror(fp))
panic("output error");
if (ferror(stdin))
panic("input error");
fclose(fp);
/* Set the x bit so that we're ready to start executing
*/
if (fchmod(fd2, S_IRUSR | S_IWUSR | S_IXUSR) < 0)
perr("cannot give away file");
close(fd2);
fprintf(stderr, "Job %ld will be executed using /bin/sh\n", jobno);
}
static int
in_job_list(long job, long *joblist, int len)
{
int i;
for (i = 0; i < len; i++)
if (job == joblist[i])
return 1;
return 0;
}
static void
list_jobs(long *joblist, int len)
{
/* List all a user's jobs in the queue, by looping through ATJOB_DIR,
* or everybody's if we are root
*/
struct passwd *pw;
DIR *spool;
struct dirent *dirent;
struct stat buf;
struct tm runtime;
unsigned long ctm;
char queue;
long jobno;
time_t runtimer;
char timestr[TIMESIZE];
int first=1;
#ifdef __FreeBSD__
(void) setlocale(LC_TIME, "");
#endif
PRIV_START
if (chdir(ATJOB_DIR) != 0)
perr("cannot change to " ATJOB_DIR);
if ((spool = opendir(".")) == NULL)
perr("cannot open " ATJOB_DIR);
/* Loop over every file in the directory
*/
while((dirent = readdir(spool)) != NULL) {
if (stat(dirent->d_name, &buf) != 0)
perr("cannot stat in " ATJOB_DIR);
/* See it's a regular file and has its x bit turned on and
* is the user's
*/
if (!S_ISREG(buf.st_mode)
|| ((buf.st_uid != real_uid) && ! (real_uid == 0))
|| !(S_IXUSR & buf.st_mode || atverify))
continue;
if(sscanf(dirent->d_name, "%c%5lx%8lx", &queue, &jobno, &ctm)!=3)
continue;
/* If jobs are given, only list those jobs */
if (joblist && !in_job_list(jobno, joblist, len))
continue;
if (atqueue && (queue != atqueue))
continue;
runtimer = 60*(time_t) ctm;
runtime = *localtime(&runtimer);
strftime(timestr, TIMESIZE, "%+", &runtime);
if (first) {
printf("Date\t\t\t\tOwner\t\tQueue\tJob#\n");
first=0;
}
pw = getpwuid(buf.st_uid);
printf("%s\t%-16s%c%s\t%ld\n",
timestr,
pw ? pw->pw_name : "???",
queue,
(S_IXUSR & buf.st_mode) ? "":"(done)",
jobno);
}
PRIV_END
closedir(spool);
}
static void
process_jobs(int argc, char **argv, int what)
{
/* Delete every argument (job - ID) given
*/
int i;
int rc;
int nofJobs;
int nofDone;
int statErrno;
struct stat buf;
DIR *spool;
struct dirent *dirent;
unsigned long ctm;
char queue;
long jobno;
nofJobs = argc - optind;
nofDone = 0;
PRIV_START
if (chdir(ATJOB_DIR) != 0)
perr("cannot change to " ATJOB_DIR);
if ((spool = opendir(".")) == NULL)
perr("cannot open " ATJOB_DIR);
PRIV_END
/* Loop over every file in the directory
*/
while((dirent = readdir(spool)) != NULL) {
PRIV_START
rc = stat(dirent->d_name, &buf);
statErrno = errno;
PRIV_END
/* There's a race condition between readdir above and stat here:
* another atrm process could have removed the file from the spool
* directory under our nose. If this happens, stat will set errno to
* ENOENT, which we shouldn't treat as fatal.
*/
if (rc != 0) {
if (statErrno == ENOENT)
continue;
else
perr("cannot stat in " ATJOB_DIR);
}
if(sscanf(dirent->d_name, "%c%5lx%8lx", &queue, &jobno, &ctm)!=3)
continue;
for (i=optind; i < argc; i++) {
if (atoi(argv[i]) == jobno) {
if ((buf.st_uid != real_uid) && !(real_uid == 0))
errx(EXIT_FAILURE, "%s: not owner", argv[i]);
switch (what) {
case ATRM:
PRIV_START
if (unlink(dirent->d_name) != 0)
perr(dirent->d_name);
PRIV_END
break;
case CAT:
{
FILE *fp;
int ch;
PRIV_START
fp = fopen(dirent->d_name,"r");
PRIV_END
if (!fp) {
perr("cannot open file");
}
while((ch = getc(fp)) != EOF) {
putchar(ch);
}
fclose(fp);
}
break;
default:
errx(EXIT_FAILURE, "internal error, process_jobs = %d",
what);
}
/* All arguments have been processed
*/
if (++nofDone == nofJobs)
goto end;
}
}
}
end:
closedir(spool);
} /* delete_jobs */
#define ATOI2(ar) ((ar)[0] - '0') * 10 + ((ar)[1] - '0'); (ar) += 2;
static time_t
ttime(const char *arg)
{
/*
* This is pretty much a copy of stime_arg1() from touch.c. I changed
* the return value and the argument list because it's more convenient
* (IMO) to do everything in one place. - Joe Halpin
*/
struct timeval tv[2];
time_t now;
struct tm *t;
int yearset;
char *p;
if (gettimeofday(&tv[0], NULL))
panic("Cannot get current time");
/* Start with the current time. */
now = tv[0].tv_sec;
if ((t = localtime(&now)) == NULL)
panic("localtime");
/* [[CC]YY]MMDDhhmm[.SS] */
if ((p = strchr(arg, '.')) == NULL)
t->tm_sec = 0; /* Seconds defaults to 0. */
else {
if (strlen(p + 1) != 2)
goto terr;
*p++ = '\0';
t->tm_sec = ATOI2(p);
}
yearset = 0;
switch(strlen(arg)) {
case 12: /* CCYYMMDDhhmm */
t->tm_year = ATOI2(arg);
t->tm_year *= 100;
yearset = 1;
/* FALLTHROUGH */
case 10: /* YYMMDDhhmm */
if (yearset) {
yearset = ATOI2(arg);
t->tm_year += yearset;
} else {
yearset = ATOI2(arg);
t->tm_year = yearset + 2000;
}
t->tm_year -= 1900; /* Convert to UNIX time. */
/* FALLTHROUGH */
case 8: /* MMDDhhmm */
t->tm_mon = ATOI2(arg);
--t->tm_mon; /* Convert from 01-12 to 00-11 */
t->tm_mday = ATOI2(arg);
t->tm_hour = ATOI2(arg);
t->tm_min = ATOI2(arg);
break;
default:
goto terr;
}
t->tm_isdst = -1; /* Figure out DST. */
tv[0].tv_sec = tv[1].tv_sec = mktime(t);
if (tv[0].tv_sec != -1)
return tv[0].tv_sec;
else
terr:
panic(
"out of range or illegal time specification: [[CC]YY]MMDDhhmm[.SS]");
}
static long *
get_job_list(int argc, char *argv[], int *joblen)
{
int i, len;
long *joblist;
char *ep;
joblist = NULL;
len = argc;
if (len > 0) {
if ((joblist = malloc(len * sizeof(*joblist))) == NULL)
panic("out of memory");
for (i = 0; i < argc; i++) {
errno = 0;
if ((joblist[i] = strtol(argv[i], &ep, 10)) < 0 ||
ep == argv[i] || *ep != '\0' || errno)
panic("invalid job number");
}
}
*joblen = len;
return joblist;
}
int
main(int argc, char **argv)
{
int c;
char queue = DEFAULT_AT_QUEUE;
char queue_set = 0;
char *pgm;
int program = AT; /* our default program */
const char *options = "q:f:t:rmvldbc"; /* default options for at */
time_t timer;
long *joblist;
int joblen;
joblist = NULL;
joblen = 0;
timer = -1;
RELINQUISH_PRIVS
/* Eat any leading paths
*/
if ((pgm = strrchr(argv[0], '/')) == NULL)
pgm = argv[0];
else
pgm++;
namep = pgm;
/* find out what this program is supposed to do
*/
if (strcmp(pgm, "atq") == 0) {
program = ATQ;
options = "q:v";
}
else if (strcmp(pgm, "atrm") == 0) {
program = ATRM;
options = "";
}
else if (strcmp(pgm, "batch") == 0) {
program = BATCH;
options = "f:q:mv";
}
/* process whatever options we can process
*/
opterr=1;
while ((c=getopt(argc, argv, options)) != -1)
switch (c) {
case 'v': /* verify time settings */
atverify = 1;
break;
case 'm': /* send mail when job is complete */
send_mail = 1;
break;
case 'f':
atinput = optarg;
break;
case 'q': /* specify queue */
if (strlen(optarg) > 1)
usage();
atqueue = queue = *optarg;
if (!(islower(queue)||isupper(queue)))
usage();
queue_set = 1;
break;
case 'd':
warnx("-d is deprecated; use -r instead");
/* fall through to 'r' */
case 'r':
if (program != AT)
usage();
program = ATRM;
options = "";
break;
case 't':
if (program != AT)
usage();
timer = ttime(optarg);
break;
case 'l':
if (program != AT)
usage();
program = ATQ;
options = "q:";
break;
case 'b':
if (program != AT)
usage();
program = BATCH;
options = "f:q:mv";
break;
case 'c':
program = CAT;
options = "";
break;
default:
usage();
break;
}
/* end of options eating
*/
/* select our program
*/
if(!check_permission())
errx(EXIT_FAILURE, "you do not have permission to use this program");
switch (program) {
case ATQ:
REDUCE_PRIV(DAEMON_UID, DAEMON_GID)
if (queue_set == 0)
joblist = get_job_list(argc - optind, argv + optind, &joblen);
list_jobs(joblist, joblen);
break;
case ATRM:
REDUCE_PRIV(DAEMON_UID, DAEMON_GID)
process_jobs(argc, argv, ATRM);
break;
case CAT:
process_jobs(argc, argv, CAT);
break;
case AT:
/*
* If timer is > -1, then the user gave the time with -t. In that
* case, it's already been set. If not, set it now.
*/
if (timer == -1)
timer = parsetime(argc, argv);
if (atverify)
{
struct tm *tm = localtime(&timer);
fprintf(stderr, "%s\n", asctime(tm));
}
writefile(timer, queue);
break;
case BATCH:
if (queue_set)
queue = toupper(queue);
else
queue = DEFAULT_BATCH_QUEUE;
if (argc > optind)
timer = parsetime(argc, argv);
else
timer = time(NULL);
if (atverify)
{
struct tm *tm = localtime(&timer);
fprintf(stderr, "%s\n", asctime(tm));
}
writefile(timer, queue);
break;
default:
panic("internal error");
break;
}
exit(EXIT_SUCCESS);
}
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