freebsd-dev/usr.sbin/lpr/common_source/common.c
Pedro F. Giffuni df57947f08 spdx: initial adoption of licensing ID tags.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Initially, only tag files that use BSD 4-Clause "Original" license.

RelNotes:	yes
Differential Revision:	https://reviews.freebsd.org/D13133
2017-11-18 14:26:50 +00:00

783 lines
22 KiB
C

/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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, WHETHER 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.
*/
#if 0
#ifndef lint
static char sccsid[] = "@(#)common.c 8.5 (Berkeley) 4/28/95";
#endif /* not lint */
#endif
#include "lp.cdefs.h" /* A cross-platform version of <sys/cdefs.h> */
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <ctype.h>
#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "lp.h"
#include "lp.local.h"
#include "pathnames.h"
/*
* Routines and data common to all the line printer functions.
*/
char line[BUFSIZ];
const char *progname; /* program name */
static int compar(const void *_p1, const void *_p2);
/*
* isdigit() takes a parameter of 'int', but expect values in the range
* of unsigned char. Define a wrapper which takes a value of type 'char',
* whether signed or unsigned, and ensure it ends up in the right range.
*/
#define isdigitch(Anychar) isdigit((u_char)(Anychar))
/*
* get_line reads a line from the control file cfp, removes tabs, converts
* new-line to null and leaves it in line.
* Returns 0 at EOF or the number of characters read.
*/
int
get_line(FILE *cfp)
{
register int linel = 0;
register char *lp = line;
register int c;
while ((c = getc(cfp)) != '\n' && (size_t)(linel+1) < sizeof(line)) {
if (c == EOF)
return(0);
if (c == '\t') {
do {
*lp++ = ' ';
linel++;
} while ((linel & 07) != 0 && (size_t)(linel+1) <
sizeof(line));
continue;
}
*lp++ = c;
linel++;
}
*lp++ = '\0';
return(linel);
}
/*
* Scan the current directory and make a list of daemon files sorted by
* creation time.
* Return the number of entries and a pointer to the list.
*/
int
getq(const struct printer *pp, struct jobqueue *(*namelist[]))
{
register struct dirent *d;
register struct jobqueue *q, **queue;
size_t arraysz, entrysz, nitems;
struct stat stbuf;
DIR *dirp;
int statres;
PRIV_START
if ((dirp = opendir(pp->spool_dir)) == NULL) {
PRIV_END
return (-1);
}
if (fstat(dirfd(dirp), &stbuf) < 0)
goto errdone;
PRIV_END
/*
* Estimate the array size by taking the size of the directory file
* and dividing it by a multiple of the minimum size entry.
*/
arraysz = (stbuf.st_size / 24);
if (arraysz < 16)
arraysz = 16;
queue = (struct jobqueue **)malloc(arraysz * sizeof(struct jobqueue *));
if (queue == NULL)
goto errdone;
nitems = 0;
while ((d = readdir(dirp)) != NULL) {
if (d->d_name[0] != 'c' || d->d_name[1] != 'f')
continue; /* daemon control files only */
PRIV_START
statres = stat(d->d_name, &stbuf);
PRIV_END
if (statres < 0)
continue; /* Doesn't exist */
entrysz = sizeof(struct jobqueue) - sizeof(q->job_cfname) +
strlen(d->d_name) + 1;
q = (struct jobqueue *)malloc(entrysz);
if (q == NULL)
goto errdone;
q->job_matched = 0;
q->job_processed = 0;
q->job_time = stbuf.st_mtime;
strcpy(q->job_cfname, d->d_name);
/*
* Check to make sure the array has space left and
* realloc the maximum size.
*/
if (++nitems > arraysz) {
queue = (struct jobqueue **)reallocarray((char *)queue,
arraysz, 2 * sizeof(struct jobqueue *));
if (queue == NULL) {
free(q);
goto errdone;
}
arraysz *= 2;
}
queue[nitems-1] = q;
}
closedir(dirp);
if (nitems)
qsort(queue, nitems, sizeof(struct jobqueue *), compar);
*namelist = queue;
return(nitems);
errdone:
closedir(dirp);
PRIV_END
return (-1);
}
/*
* Compare modification times.
*/
static int
compar(const void *p1, const void *p2)
{
const struct jobqueue *qe1, *qe2;
qe1 = *(const struct jobqueue * const *)p1;
qe2 = *(const struct jobqueue * const *)p2;
if (qe1->job_time < qe2->job_time)
return (-1);
if (qe1->job_time > qe2->job_time)
return (1);
/*
* At this point, the two files have the same last-modification time.
* return a result based on filenames, so that 'cfA001some.host' will
* come before 'cfA002some.host'. Since the jobid ('001') will wrap
* around when it gets to '999', we also assume that '9xx' jobs are
* older than '0xx' jobs.
*/
if ((qe1->job_cfname[3] == '9') && (qe2->job_cfname[3] == '0'))
return (-1);
if ((qe1->job_cfname[3] == '0') && (qe2->job_cfname[3] == '9'))
return (1);
return (strcmp(qe1->job_cfname, qe2->job_cfname));
}
/*
* A simple routine to determine the job number for a print job based on
* the name of its control file. The algorithm used here may look odd, but
* the main issue is that all parts of `lpd', `lpc', `lpq' & `lprm' must be
* using the same algorithm, whatever that algorithm may be. If the caller
* provides a non-null value for ''hostpp', then this returns a pointer to
* the start of the hostname (or IP address?) as found in the filename.
*
* Algorithm: The standard `cf' file has the job number start in position 4,
* but some implementations have that as an extra file-sequence letter, and
* start the job number in position 5. The job number is usually three bytes,
* but may be as many as five. Confusing matters still more, some Windows
* print servers will append an IP address to the job number, instead of
* the expected hostname. So, if the job number ends with a '.', then
* assume the correct jobnum value is the first three digits.
*/
int
calc_jobnum(const char *cfname, const char **hostpp)
{
int jnum;
const char *cp, *numstr, *hoststr;
numstr = cfname + 3;
if (!isdigitch(*numstr))
numstr++;
jnum = 0;
for (cp = numstr; (cp < numstr + 5) && isdigitch(*cp); cp++)
jnum = jnum * 10 + (*cp - '0');
hoststr = cp;
/*
* If the filename was built with an IP number instead of a hostname,
* then recalculate using only the first three digits found.
*/
while(isdigitch(*cp))
cp++;
if (*cp == '.') {
jnum = 0;
for (cp = numstr; (cp < numstr + 3) && isdigitch(*cp); cp++)
jnum = jnum * 10 + (*cp - '0');
hoststr = cp;
}
if (hostpp != NULL)
*hostpp = hoststr;
return (jnum);
}
/* sleep n milliseconds */
void
delay(int millisec)
{
struct timeval tdelay;
if (millisec <= 0 || millisec > 10000)
fatal((struct printer *)0, /* fatal() knows how to deal */
"unreasonable delay period (%d)", millisec);
tdelay.tv_sec = millisec / 1000;
tdelay.tv_usec = millisec * 1000 % 1000000;
(void) select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &tdelay);
}
char *
lock_file_name(const struct printer *pp, char *buf, size_t len)
{
static char staticbuf[MAXPATHLEN];
if (buf == NULL)
buf = staticbuf;
if (len == 0)
len = MAXPATHLEN;
if (pp->lock_file[0] == '/')
strlcpy(buf, pp->lock_file, len);
else
snprintf(buf, len, "%s/%s", pp->spool_dir, pp->lock_file);
return buf;
}
char *
status_file_name(const struct printer *pp, char *buf, size_t len)
{
static char staticbuf[MAXPATHLEN];
if (buf == NULL)
buf = staticbuf;
if (len == 0)
len = MAXPATHLEN;
if (pp->status_file[0] == '/')
strlcpy(buf, pp->status_file, len);
else
snprintf(buf, len, "%s/%s", pp->spool_dir, pp->status_file);
return buf;
}
/*
* Routine to change operational state of a print queue. The operational
* state is indicated by the access bits on the lock file for the queue.
* At present, this is only called from various routines in lpc/cmds.c.
*
* XXX - Note that this works by changing access-bits on the
* file, and you can only do that if you are the owner of
* the file, or root. Thus, this won't really work for
* userids in the "LPR_OPER" group, unless lpc is running
* setuid to root (or maybe setuid to daemon).
* Generally lpc is installed setgid to daemon, but does
* not run setuid.
*/
int
set_qstate(int action, const char *lfname)
{
struct stat stbuf;
mode_t chgbits, newbits, oldmask;
const char *failmsg, *okmsg;
static const char *nomsg = "no state msg";
int chres, errsav, fd, res, statres;
/*
* Find what the current access-bits are.
*/
memset(&stbuf, 0, sizeof(stbuf));
PRIV_START
statres = stat(lfname, &stbuf);
errsav = errno;
PRIV_END
if ((statres < 0) && (errsav != ENOENT)) {
printf("\tcannot stat() lock file\n");
return (SQS_STATFAIL);
/* NOTREACHED */
}
/*
* Determine which bit(s) should change for the requested action.
*/
chgbits = stbuf.st_mode;
newbits = LOCK_FILE_MODE;
okmsg = NULL;
failmsg = NULL;
if (action & SQS_QCHANGED) {
chgbits |= LFM_RESET_QUE;
newbits |= LFM_RESET_QUE;
/* The okmsg is not actually printed for this case. */
okmsg = nomsg;
failmsg = "set queue-changed";
}
if (action & SQS_DISABLEQ) {
chgbits |= LFM_QUEUE_DIS;
newbits |= LFM_QUEUE_DIS;
okmsg = "queuing disabled";
failmsg = "disable queuing";
}
if (action & SQS_STOPP) {
chgbits |= LFM_PRINT_DIS;
newbits |= LFM_PRINT_DIS;
okmsg = "printing disabled";
failmsg = "disable printing";
if (action & SQS_DISABLEQ) {
okmsg = "printer and queuing disabled";
failmsg = "disable queuing and printing";
}
}
if (action & SQS_ENABLEQ) {
chgbits &= ~LFM_QUEUE_DIS;
newbits &= ~LFM_QUEUE_DIS;
okmsg = "queuing enabled";
failmsg = "enable queuing";
}
if (action & SQS_STARTP) {
chgbits &= ~LFM_PRINT_DIS;
newbits &= ~LFM_PRINT_DIS;
okmsg = "printing enabled";
failmsg = "enable printing";
}
if (okmsg == NULL) {
/* This routine was called with an invalid action. */
printf("\t<error in set_qstate!>\n");
return (SQS_PARMERR);
/* NOTREACHED */
}
res = 0;
if (statres >= 0) {
/* The file already exists, so change the access. */
PRIV_START
chres = chmod(lfname, chgbits);
errsav = errno;
PRIV_END
res = SQS_CHGOK;
if (chres < 0)
res = SQS_CHGFAIL;
} else if (newbits == LOCK_FILE_MODE) {
/*
* The file does not exist, but the state requested is
* the same as the default state when no file exists.
* Thus, there is no need to create the file.
*/
res = SQS_SKIPCREOK;
} else {
/*
* The file did not exist, so create it with the
* appropriate access bits for the requested action.
* Push a new umask around that create, to make sure
* all the read/write bits are set as desired.
*/
oldmask = umask(S_IWOTH);
PRIV_START
fd = open(lfname, O_WRONLY|O_CREAT, newbits);
errsav = errno;
PRIV_END
umask(oldmask);
res = SQS_CREFAIL;
if (fd >= 0) {
res = SQS_CREOK;
close(fd);
}
}
switch (res) {
case SQS_CHGOK:
case SQS_CREOK:
case SQS_SKIPCREOK:
if (okmsg != nomsg)
printf("\t%s\n", okmsg);
break;
case SQS_CREFAIL:
printf("\tcannot create lock file: %s\n",
strerror(errsav));
break;
default:
printf("\tcannot %s: %s\n", failmsg, strerror(errsav));
break;
}
return (res);
}
/* routine to get a current timestamp, optionally in a standard-fmt string */
void
lpd_gettime(struct timespec *tsp, char *strp, size_t strsize)
{
struct timespec local_ts;
struct timeval btime;
char tempstr[TIMESTR_SIZE];
#ifdef STRFTIME_WRONG_z
char *destp;
#endif
if (tsp == NULL)
tsp = &local_ts;
/* some platforms have a routine called clock_gettime, but the
* routine does nothing but return "not implemented". */
memset(tsp, 0, sizeof(struct timespec));
if (clock_gettime(CLOCK_REALTIME, tsp)) {
/* nanosec-aware rtn failed, fall back to microsec-aware rtn */
memset(tsp, 0, sizeof(struct timespec));
gettimeofday(&btime, NULL);
tsp->tv_sec = btime.tv_sec;
tsp->tv_nsec = btime.tv_usec * 1000;
}
/* caller may not need a character-ized version */
if ((strp == NULL) || (strsize < 1))
return;
strftime(tempstr, TIMESTR_SIZE, LPD_TIMESTAMP_PATTERN,
localtime(&tsp->tv_sec));
/*
* This check is for implementations of strftime which treat %z
* (timezone as [+-]hhmm ) like %Z (timezone as characters), or
* completely ignore %z. This section is not needed on freebsd.
* I'm not sure this is completely right, but it should work OK
* for EST and EDT...
*/
#ifdef STRFTIME_WRONG_z
destp = strrchr(tempstr, ':');
if (destp != NULL) {
destp += 3;
if ((*destp != '+') && (*destp != '-')) {
char savday[6];
int tzmin = timezone / 60;
int tzhr = tzmin / 60;
if (daylight)
tzhr--;
strcpy(savday, destp + strlen(destp) - 4);
snprintf(destp, (destp - tempstr), "%+03d%02d",
(-1*tzhr), tzmin % 60);
strcat(destp, savday);
}
}
#endif
if (strsize > TIMESTR_SIZE) {
strsize = TIMESTR_SIZE;
strp[TIMESTR_SIZE+1] = '\0';
}
strlcpy(strp, tempstr, strsize);
}
/* routines for writing transfer-statistic records */
void
trstat_init(struct printer *pp, const char *fname, int filenum)
{
register const char *srcp;
register char *destp, *endp;
/*
* Figure out the job id of this file. The filename should be
* 'cf', 'df', or maybe 'tf', followed by a letter (or sometimes
* two), followed by the jobnum, followed by a hostname.
* The jobnum is usually 3 digits, but might be as many as 5.
* Note that some care has to be taken parsing this, as the
* filename could be coming from a remote-host, and thus might
* not look anything like what is expected...
*/
memset(pp->jobnum, 0, sizeof(pp->jobnum));
pp->jobnum[0] = '0';
srcp = strchr(fname, '/');
if (srcp == NULL)
srcp = fname;
destp = &(pp->jobnum[0]);
endp = destp + 5;
while (*srcp != '\0' && (*srcp < '0' || *srcp > '9'))
srcp++;
while (*srcp >= '0' && *srcp <= '9' && destp < endp)
*(destp++) = *(srcp++);
/* get the starting time in both numeric and string formats, and
* save those away along with the file-number */
pp->jobdfnum = filenum;
lpd_gettime(&pp->tr_start, pp->tr_timestr, (size_t)TIMESTR_SIZE);
return;
}
void
trstat_write(struct printer *pp, tr_sendrecv sendrecv, size_t bytecnt,
const char *userid, const char *otherhost, const char *orighost)
{
#define STATLINE_SIZE 1024
double trtime;
size_t remspace;
int statfile;
char thishost[MAXHOSTNAMELEN], statline[STATLINE_SIZE];
char *eostat;
const char *lprhost, *recvdev, *recvhost, *rectype;
const char *sendhost, *statfname;
#define UPD_EOSTAT(xStr) do { \
eostat = strchr(xStr, '\0'); \
remspace = eostat - xStr; \
} while(0)
lpd_gettime(&pp->tr_done, NULL, (size_t)0);
trtime = DIFFTIME_TS(pp->tr_done, pp->tr_start);
gethostname(thishost, sizeof(thishost));
lprhost = sendhost = recvhost = recvdev = NULL;
switch (sendrecv) {
case TR_SENDING:
rectype = "send";
statfname = pp->stat_send;
sendhost = thishost;
recvhost = otherhost;
break;
case TR_RECVING:
rectype = "recv";
statfname = pp->stat_recv;
sendhost = otherhost;
recvhost = thishost;
break;
case TR_PRINTING:
/*
* This case is for copying to a device (presumably local,
* though filters using things like 'net/CAP' can confuse
* this assumption...).
*/
rectype = "prnt";
statfname = pp->stat_send;
sendhost = thishost;
recvdev = _PATH_DEFDEVLP;
if (pp->lp) recvdev = pp->lp;
break;
default:
/* internal error... should we syslog/printf an error? */
return;
}
if (statfname == NULL)
return;
/*
* the original-host and userid are found out by reading thru the
* cf (control-file) for the job. Unfortunately, on incoming jobs
* the df's (data-files) are sent before the matching cf, so the
* orighost & userid are generally not-available for incoming jobs.
*
* (it would be nice to create a work-around for that..)
*/
if (orighost && (*orighost != '\0'))
lprhost = orighost;
else
lprhost = ".na.";
if (*userid == '\0')
userid = NULL;
/*
* Format of statline.
* Some of the keywords listed here are not implemented here, but
* they are listed to reserve the meaning for a given keyword.
* Fields are separated by a blank. The fields in statline are:
* <tstamp> - time the transfer started
* <ptrqueue> - name of the printer queue (the short-name...)
* <hname> - hostname the file originally came from (the
* 'lpr host'), if known, or "_na_" if not known.
* <xxx> - id of job from that host (generally three digits)
* <n> - file count (# of file within job)
* <rectype> - 4-byte field indicating the type of transfer
* statistics record. "send" means it's from the
* host sending a datafile, "recv" means it's from
* a host as it receives a datafile.
* user=<userid> - user who sent the job (if known)
* secs=<n> - seconds it took to transfer the file
* bytes=<n> - number of bytes transferred (ie, "bytecount")
* bps=<n.n>e<n> - Bytes/sec (if the transfer was "big enough"
* for this to be useful)
* ! top=<str> - type of printer (if the type is defined in
* printcap, and if this statline is for sending
* a file to that ptr)
* ! qls=<n> - queue-length at start of send/print-ing a job
* ! qle=<n> - queue-length at end of send/print-ing a job
* sip=<addr> - IP address of sending host, only included when
* receiving a job.
* shost=<hname> - sending host (if that does != the original host)
* rhost=<hname> - hostname receiving the file (ie, "destination")
* rdev=<dev> - device receiving the file, when the file is being
* send to a device instead of a remote host.
*
* Note: A single print job may be transferred multiple times. The
* original 'lpr' occurs on one host, and that original host might
* send to some interim host (or print server). That interim host
* might turn around and send the job to yet another host (most likely
* the real printer). The 'shost=' parameter is only included if the
* sending host for this particular transfer is NOT the same as the
* host which did the original 'lpr'.
*
* Many values have 'something=' tags before them, because they are
* in some sense "optional", or their order may vary. "Optional" may
* mean in the sense that different SITES might choose to have other
* fields in the record, or that some fields are only included under
* some circumstances. Programs processing these records should not
* assume the order or existence of any of these keyword fields.
*/
snprintf(statline, STATLINE_SIZE, "%s %s %s %s %03ld %s",
pp->tr_timestr, pp->printer, lprhost, pp->jobnum,
pp->jobdfnum, rectype);
UPD_EOSTAT(statline);
if (userid != NULL) {
snprintf(eostat, remspace, " user=%s", userid);
UPD_EOSTAT(statline);
}
snprintf(eostat, remspace, " secs=%#.2f bytes=%lu", trtime,
(unsigned long)bytecnt);
UPD_EOSTAT(statline);
/*
* The bps field duplicates info from bytes and secs, so do
* not bother to include it for very small files.
*/
if ((bytecnt > 25000) && (trtime > 1.1)) {
snprintf(eostat, remspace, " bps=%#.2e",
((double)bytecnt/trtime));
UPD_EOSTAT(statline);
}
if (sendrecv == TR_RECVING) {
if (remspace > 5+strlen(from_ip) ) {
snprintf(eostat, remspace, " sip=%s", from_ip);
UPD_EOSTAT(statline);
}
}
if (0 != strcmp(lprhost, sendhost)) {
if (remspace > 7+strlen(sendhost) ) {
snprintf(eostat, remspace, " shost=%s", sendhost);
UPD_EOSTAT(statline);
}
}
if (recvhost) {
if (remspace > 7+strlen(recvhost) ) {
snprintf(eostat, remspace, " rhost=%s", recvhost);
UPD_EOSTAT(statline);
}
}
if (recvdev) {
if (remspace > 6+strlen(recvdev) ) {
snprintf(eostat, remspace, " rdev=%s", recvdev);
UPD_EOSTAT(statline);
}
}
if (remspace > 1) {
strcpy(eostat, "\n");
} else {
/* probably should back up to just before the final " x=".. */
strcpy(statline+STATLINE_SIZE-2, "\n");
}
statfile = open(statfname, O_WRONLY|O_APPEND, 0664);
if (statfile < 0) {
/* statfile was given, but we can't open it. should we
* syslog/printf this as an error? */
return;
}
write(statfile, statline, strlen(statline));
close(statfile);
return;
#undef UPD_EOSTAT
}
#include <stdarg.h>
void
fatal(const struct printer *pp, const char *msg, ...)
{
va_list ap;
va_start(ap, msg);
/* this error message is being sent to the 'from_host' */
if (from_host != local_host)
(void)printf("%s: ", local_host);
(void)printf("%s: ", progname);
if (pp && pp->printer)
(void)printf("%s: ", pp->printer);
(void)vprintf(msg, ap);
va_end(ap);
(void)putchar('\n');
exit(1);
}
/*
* Close all file descriptors from START on up.
*/
void
closeallfds(int start)
{
int stop;
if (USE_CLOSEFROM) /* The faster, modern solution */
closefrom(start);
else {
/* This older logic can be pretty awful on some OS's. The
* getdtablesize() might return ``infinity'', and then this
* will waste a lot of time closing file descriptors which
* had never been open()-ed. */
stop = getdtablesize();
for (; start < stop; start++)
close(start);
}
}