freebsd-dev/usr.sbin/sendmail/mail.local/mail.local.c
Peter Wemm b0591e84e9 Merge in our changes from src/libexec/mail.local. This version doesn't
violate disk quotas, has more robust locking, is still being developed,
etc.  The main changes merged in were the ability to not fsync() the
mailbox, not do biff/comsat broadcasts, man page fixes.
1996-10-29 05:22:52 +00:00

934 lines
21 KiB
C

/*-
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* 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.
*
* $Id$
*/
#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1990, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)mail.local.c 8.30 (Berkeley) 10/9/96";
#endif /* not lint */
/*
* This is not intended to compile on System V derived systems
* such as Solaris or HP-UX, since they use a totally different
* approach to mailboxes (essentially, they have a setgid program
* rather than setuid, and they rely on the ability to "give away"
* files to do their work). IT IS NOT A BUG that this doesn't
* compile on such architectures.
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>
#ifdef EX_OK
# undef EX_OK /* unistd.h may have another use for this */
#endif
#include <sysexits.h>
#include <ctype.h>
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#if (defined(sun) && defined(__svr4__)) || defined(__SVR4)
# define USE_LOCKF 1
# define USE_SETEUID 1
# define _PATH_MAILDIR "/var/mail"
#endif
#if defined(_AIX)
# define USE_LOCKF 1
# define USE_VSYSLOG 0
#endif
#if defined(ultrix)
# define USE_VSYSLOG 0
#endif
#if defined(__osf__)
# define USE_VSYSLOG 0
#endif
#if defined(NeXT)
# include <libc.h>
# define _PATH_MAILDIR "/usr/spool/mail"
# define __dead /* empty */
# define S_IRUSR S_IREAD
# define S_IWUSR S_IWRITE
#endif
/*
* If you don't have flock, you could try using lockf instead.
*/
#ifdef USE_LOCKF
# define flock(a, b) lockf(a, b, 0)
# define LOCK_EX F_LOCK
#endif
#ifndef USE_VSYSLOG
# define USE_VSYSLOG 1
#endif
#ifndef LOCK_EX
# include <sys/file.h>
#endif
#ifdef BSD4_4
# include "pathnames.h"
#endif
#ifndef __P
# ifdef __STDC__
# define __P(protos) protos
# else
# define __P(protos) ()
# define const
# endif
#endif
#ifndef __dead
# if defined(__GNUC__) && (__GNUC__ < 2 || __GNUC_MINOR__ < 5) && !defined(__STRICT_ANSI__)
# define __dead __volatile
# else
# define __dead
# endif
#endif
#ifndef BSD4_4
# define _BSD_VA_LIST_ va_list
#endif
#if !defined(BSD4_4) && !defined(linux)
extern char *strerror __P((int));
extern int snprintf __P((char *, int, const char *, ...));
extern FILE *fdopen __P((int, const char *));
#endif
/*
* If you don't have setreuid, and you have saved uids, and you have
* a seteuid() call that doesn't try to emulate using setuid(), then
* you can try defining USE_SETEUID.
*/
#ifdef USE_SETEUID
# define setreuid(r, e) seteuid(e)
#endif
#ifndef _PATH_LOCTMP
# define _PATH_LOCTMP "/tmp/local.XXXXXX"
#endif
#ifndef _PATH_MAILDIR
# define _PATH_MAILDIR "/var/spool/mail"
#endif
#ifndef S_ISREG
# define S_ISREG(mode) (((mode) & _S_IFMT) == S_IFREG)
#endif
int eval = EX_OK; /* sysexits.h error value. */
void deliver __P((int, char *, int));
void e_to_sys __P((int));
void err __P((const char *, ...)) __dead2;
void notifybiff __P((char *));
int store __P((char *));
void usage __P((void));
void vwarn __P((const char *, _BSD_VA_LIST_));
void warn __P((const char *, ...));
void lockmbox __P((char *));
void unlockmbox __P((void));
int
main(argc, argv)
int argc;
char *argv[];
{
struct passwd *pw;
int ch, fd, nobiff;
uid_t uid;
char *from;
extern char *optarg;
extern int optind;
/* make sure we have some open file descriptors */
for (fd = 10; fd < 30; fd++)
(void) close(fd);
/* use a reasonable umask */
(void) umask(0077);
#ifdef LOG_MAIL
openlog("mail.local", 0, LOG_MAIL);
#else
openlog("mail.local", 0);
#endif
from = NULL;
nobiff = 0;
while ((ch = getopt(argc, argv, "bdf:r:")) != EOF)
switch(ch) {
case 'b':
nobiff++;
break;
case 'd': /* Backward compatible. */
break;
case 'f':
case 'r': /* Backward compatible. */
if (from != NULL) {
warn("multiple -f options");
usage();
}
from = optarg;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (!*argv)
usage();
/*
* If from not specified, use the name from getlogin() if the
* uid matches, otherwise, use the name from the password file
* corresponding to the uid.
*/
uid = getuid();
if (!from && (!(from = getlogin()) ||
!(pw = getpwnam(from)) || pw->pw_uid != uid))
from = (pw = getpwuid(uid)) ? pw->pw_name : "???";
/*
* There is no way to distinguish the error status of one delivery
* from the rest of the deliveries. So, if we failed hard on one
* or more deliveries, but had no failures on any of the others, we
* return a hard failure. If we failed temporarily on one or more
* deliveries, we return a temporary failure regardless of the other
* failures. This results in the delivery being reattempted later
* at the expense of repeated failures and multiple deliveries.
*/
for (fd = store(from); *argv; ++argv)
deliver(fd, *argv, nobiff);
exit(eval);
}
int
store(from)
char *from;
{
FILE *fp;
time_t tval;
int fd, eline;
char line[2048];
char tmpbuf[sizeof _PATH_LOCTMP + 1];
strcpy(tmpbuf, _PATH_LOCTMP);
if ((fd = mkstemp(tmpbuf)) == -1 || (fp = fdopen(fd, "w+")) == NULL) {
e_to_sys(errno);
err("unable to open temporary file");
}
(void)unlink(tmpbuf);
(void)time(&tval);
(void)fprintf(fp, "From %s %s", from, ctime(&tval));
line[0] = '\0';
for (eline = 1; fgets(line, sizeof(line), stdin);) {
if (line[0] == '\n')
eline = 1;
else {
if (eline && line[0] == 'F' &&
!memcmp(line, "From ", 5))
(void)putc('>', fp);
eline = 0;
}
(void)fprintf(fp, "%s", line);
if (ferror(fp)) {
e_to_sys(errno);
err("temporary file write error");
}
}
/* If message not newline terminated, need an extra. */
if (!strchr(line, '\n'))
(void)putc('\n', fp);
/* Output a newline; note, empty messages are allowed. */
(void)putc('\n', fp);
if (fflush(fp) == EOF || ferror(fp)) {
e_to_sys(errno);
err("temporary file write error");
}
return (fd);
}
void
deliver(fd, name, nobiff)
int fd, nobiff;
char *name;
{
struct stat fsb, sb;
struct passwd *pw;
int mbfd, nr, nw, off;
char *p;
char biffmsg[100], buf[8*1024], path[MAXPATHLEN];
off_t curoff;
/*
* Disallow delivery to unknown names -- special mailboxes can be
* handled in the sendmail aliases file.
*/
if (!(pw = getpwnam(name))) {
if (eval != EX_TEMPFAIL)
eval = EX_UNAVAILABLE;
warn("unknown name: %s", name);
return;
}
endpwent();
/*
* Keep name reasonably short to avoid buffer overruns.
* This isn't necessary on BSD because of the proper
* definition of snprintf(), but it can cause problems
* on other systems.
* Also, clear out any bogus characters.
*/
if (strlen(name) > 40)
name[40] = '\0';
for (p = name; *p != '\0'; p++)
{
if (!isascii(*p))
*p &= 0x7f;
else if (!isprint(*p))
*p = '.';
}
(void)snprintf(path, sizeof(path), "%s/%s", _PATH_MAILDIR, name);
/*
* If the mailbox is linked or a symlink, fail. There's an obvious
* race here, that the file was replaced with a symbolic link after
* the lstat returned, but before the open. We attempt to detect
* this by comparing the original stat information and information
* returned by an fstat of the file descriptor returned by the open.
*
* NB: this is a symptom of a larger problem, that the mail spooling
* directory is writeable by the wrong users. If that directory is
* writeable, system security is compromised for other reasons, and
* it cannot be fixed here.
*
* If we created the mailbox, set the owner/group. If that fails,
* just return. Another process may have already opened it, so we
* can't unlink it. Historically, binmail set the owner/group at
* each mail delivery. We no longer do this, assuming that if the
* ownership or permissions were changed there was a reason.
*
* XXX
* open(2) should support flock'ing the file.
*/
tryagain:
lockmbox(path);
if (lstat(path, &sb)) {
mbfd = open(path,
O_APPEND|O_CREAT|O_EXCL|O_WRONLY, S_IRUSR|S_IWUSR);
if (mbfd == -1) {
if (errno == EEXIST)
goto tryagain;
} else if (fchown(mbfd, pw->pw_uid, pw->pw_gid)) {
e_to_sys(errno);
warn("chown %u.%u: %s", pw->pw_uid, pw->pw_gid, name);
goto err1;
}
} else if (sb.st_nlink != 1 || !S_ISREG(sb.st_mode)) {
e_to_sys(errno);
warn("%s: irregular file", path);
goto err0;
} else if (sb.st_uid != pw->pw_uid) {
eval = EX_CANTCREAT;
warn("%s: wrong ownership (%d)", path, sb.st_uid);
goto err0;
} else {
mbfd = open(path, O_APPEND|O_WRONLY, 0);
if (mbfd != -1 &&
(fstat(mbfd, &fsb) || fsb.st_nlink != 1 ||
!S_ISREG(fsb.st_mode) || sb.st_dev != fsb.st_dev ||
sb.st_ino != fsb.st_ino || sb.st_uid != fsb.st_uid)) {
eval = EX_CANTCREAT;
warn("%s: file changed after open", path);
goto err1;
}
}
if (mbfd == -1) {
e_to_sys(errno);
warn("%s: %s", path, strerror(errno));
goto err0;
}
/* Wait until we can get a lock on the file. */
if (flock(mbfd, LOCK_EX)) {
e_to_sys(errno);
warn("%s: %s", path, strerror(errno));
goto err1;
}
if (!nobiff) {
/* Get the starting offset of the new message for biff. */
curoff = lseek(mbfd, (off_t)0, SEEK_END);
(void)snprintf(biffmsg, sizeof(biffmsg),
sizeof curoff > sizeof(long) ? "%s@%qd\n" : "%s@%ld\n",
name, curoff);
}
/* Copy the message into the file. */
if (lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) {
e_to_sys(errno);
warn("temporary file: %s", strerror(errno));
goto err1;
}
if (setreuid(0, pw->pw_uid) < 0) {
e_to_sys(errno);
warn("setreuid(0, %d): %s (r=%d, e=%d)",
pw->pw_uid, strerror(errno), getuid(), geteuid());
goto err1;
}
#ifdef DEBUG
printf("new euid = %d\n", geteuid());
#endif
while ((nr = read(fd, buf, sizeof(buf))) > 0)
for (off = 0; off < nr; off += nw)
if ((nw = write(mbfd, buf + off, nr - off)) < 0) {
e_to_sys(errno);
warn("%s: %s", path, strerror(errno));
goto err3;
}
if (nr < 0) {
e_to_sys(errno);
warn("temporary file: %s", strerror(errno));
err3:
if (setreuid(0, 0) < 0) {
e_to_sys(errno);
warn("setreuid(0, 0): %s", strerror(errno));
}
#ifdef DEBUG
printf("reset euid = %d\n", geteuid());
#endif
err2: (void)ftruncate(mbfd, curoff);
err1: (void)close(mbfd);
err0: unlockmbox();
return;
}
#if !defined(DONT_FSYNC)
/* Flush to disk, don't wait for update. */
if (fsync(mbfd)) {
e_to_sys(errno);
warn("%s: %s", path, strerror(errno));
goto err3;
}
#endif
/* Close and check -- NFS doesn't write until the close. */
if (close(mbfd)) {
e_to_sys(errno);
warn("%s: %s", path, strerror(errno));
unlockmbox();
return;
}
if (setreuid(0, 0) < 0) {
e_to_sys(errno);
warn("setreuid(0, 0): %s", strerror(errno));
}
#ifdef DEBUG
printf("reset euid = %d\n", geteuid());
#endif
unlockmbox();
if (!nobiff)
notifybiff(biffmsg);
}
/*
* user.lock files are necessary for compatibility with other
* systems, e.g., when the mail spool file is NFS exported.
* Alas, mailbox locking is more than just a local matter.
* EPA 11/94.
*/
char lockname[MAXPATHLEN];
int locked = 0;
void
lockmbox(path)
char *path;
{
int statfailed = 0;
if (locked)
return;
sprintf(lockname, "%s.lock", path);
for (;; sleep(5)) {
int fd;
struct stat st;
time_t now;
fd = open(lockname, O_WRONLY|O_EXCL|O_CREAT, 0);
if (fd >= 0) {
locked = 1;
close(fd);
return;
}
if (stat(lockname, &st) < 0) {
if (statfailed++ > 5)
return;
continue;
}
statfailed = 0;
time(&now);
if (now < st.st_ctime + 300)
continue;
unlink(lockname);
}
}
void
unlockmbox()
{
if (!locked)
return;
unlink(lockname);
locked = 0;
}
void
notifybiff(msg)
char *msg;
{
static struct sockaddr_in addr;
static int f = -1;
struct hostent *hp;
struct servent *sp;
int len;
if (!addr.sin_family) {
/* Be silent if biff service not available. */
if (!(sp = getservbyname("biff", "udp")))
return;
if (!(hp = gethostbyname("localhost"))) {
warn("localhost: %s", strerror(errno));
return;
}
addr.sin_family = hp->h_addrtype;
memcpy(&addr.sin_addr, hp->h_addr, hp->h_length);
addr.sin_port = sp->s_port;
}
if (f < 0 && (f = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
warn("socket: %s", strerror(errno));
return;
}
len = strlen(msg) + 1;
if (sendto(f, msg, len, 0, (struct sockaddr *)&addr, sizeof(addr))
!= len)
warn("sendto biff: %s", strerror(errno));
}
void
usage()
{
eval = EX_USAGE;
err("usage: mail.local [-b] [-f from] user ...");
}
#if __STDC__
void
err(const char *fmt, ...)
#else
void
err(fmt, va_alist)
const char *fmt;
va_dcl
#endif
{
va_list ap;
#if __STDC__
va_start(ap, fmt);
#else
va_start(ap);
#endif
vwarn(fmt, ap);
va_end(ap);
exit(eval);
}
void
#if __STDC__
warn(const char *fmt, ...)
#else
warn(fmt, va_alist)
const char *fmt;
va_dcl
#endif
{
va_list ap;
#if __STDC__
va_start(ap, fmt);
#else
va_start(ap);
#endif
vwarn(fmt, ap);
va_end(ap);
}
void
vwarn(fmt, ap)
const char *fmt;
_BSD_VA_LIST_ ap;
{
/*
* Log the message to stderr.
*
* Don't use LOG_PERROR as an openlog() flag to do this,
* it's not portable enough.
*/
if (eval != EX_USAGE)
(void)fprintf(stderr, "mail.local: ");
(void)vfprintf(stderr, fmt, ap);
(void)fprintf(stderr, "\n");
#if USE_VSYSLOG
/* Log the message to syslog. */
vsyslog(LOG_ERR, fmt, ap);
#else
{
char fmtbuf[10240];
(void) sprintf(fmtbuf, fmt, ap);
syslog(LOG_ERR, "%s", fmtbuf);
}
#endif
}
/*
* e_to_sys --
* Guess which errno's are temporary. Gag me.
*/
void
e_to_sys(num)
int num;
{
/* Temporary failures override hard errors. */
if (eval == EX_TEMPFAIL)
return;
switch(num) { /* Hopefully temporary errors. */
#ifdef EAGAIN
case EAGAIN: /* Resource temporarily unavailable */
#endif
#ifdef EDQUOT
case EDQUOT: /* Disc quota exceeded */
#endif
#ifdef EBUSY
case EBUSY: /* Device busy */
#endif
#ifdef EPROCLIM
case EPROCLIM: /* Too many processes */
#endif
#ifdef EUSERS
case EUSERS: /* Too many users */
#endif
#ifdef ECONNABORTED
case ECONNABORTED: /* Software caused connection abort */
#endif
#ifdef ECONNREFUSED
case ECONNREFUSED: /* Connection refused */
#endif
#ifdef ECONNRESET
case ECONNRESET: /* Connection reset by peer */
#endif
#ifdef EDEADLK
case EDEADLK: /* Resource deadlock avoided */
#endif
#ifdef EFBIG
case EFBIG: /* File too large */
#endif
#ifdef EHOSTDOWN
case EHOSTDOWN: /* Host is down */
#endif
#ifdef EHOSTUNREACH
case EHOSTUNREACH: /* No route to host */
#endif
#ifdef EMFILE
case EMFILE: /* Too many open files */
#endif
#ifdef ENETDOWN
case ENETDOWN: /* Network is down */
#endif
#ifdef ENETRESET
case ENETRESET: /* Network dropped connection on reset */
#endif
#ifdef ENETUNREACH
case ENETUNREACH: /* Network is unreachable */
#endif
#ifdef ENFILE
case ENFILE: /* Too many open files in system */
#endif
#ifdef ENOBUFS
case ENOBUFS: /* No buffer space available */
#endif
#ifdef ENOMEM
case ENOMEM: /* Cannot allocate memory */
#endif
#ifdef ENOSPC
case ENOSPC: /* No space left on device */
#endif
#ifdef EROFS
case EROFS: /* Read-only file system */
#endif
#ifdef ESTALE
case ESTALE: /* Stale NFS file handle */
#endif
#ifdef ETIMEDOUT
case ETIMEDOUT: /* Connection timed out */
#endif
#if defined(EWOULDBLOCK) && EWOULDBLOCK != EAGAIN && EWOULDBLOCK != EDEADLK
case EWOULDBLOCK: /* Operation would block. */
#endif
eval = EX_TEMPFAIL;
break;
default:
eval = EX_UNAVAILABLE;
break;
}
}
#if !defined(BSD4_4) && !defined(__osf__)
char *
strerror(eno)
int eno;
{
extern int sys_nerr;
extern char *sys_errlist[];
static char ebuf[60];
if (eno >= 0 && eno <= sys_nerr)
return sys_errlist[eno];
(void) sprintf(ebuf, "Error %d", eno);
return ebuf;
}
# endif
#if !defined(BSD4_4) && !defined(linux)
# if __STDC__
snprintf(char *buf, int bufsiz, const char *fmt, ...)
# else
snprintf(buf, bufsiz, fmt, va_alist)
char *buf;
int bufsiz;
const char *fmt;
va_dcl
# endif
{
va_list ap;
# if __STDC__
va_start(ap, fmt);
# else
va_start(ap);
# endif
vsprintf(buf, fmt, ap);
va_end(ap);
}
#endif
#ifdef ultrix
/*
* Copyright (c) 1987, 1993
* The Regents of the University of California. All rights reserved.
*
* 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 defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)mktemp.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
static int _gettemp();
mkstemp(path)
char *path;
{
int fd;
return (_gettemp(path, &fd) ? fd : -1);
}
/*
char *
mktemp(path)
char *path;
{
return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
}
*/
static
_gettemp(path, doopen)
char *path;
register int *doopen;
{
extern int errno;
register char *start, *trv;
struct stat sbuf;
u_int pid;
pid = getpid();
for (trv = path; *trv; ++trv); /* extra X's get set to 0's */
while (*--trv == 'X') {
*trv = (pid % 10) + '0';
pid /= 10;
}
/*
* check the target directory; if you have six X's and it
* doesn't exist this runs for a *very* long time.
*/
for (start = trv + 1;; --trv) {
if (trv <= path)
break;
if (*trv == '/') {
*trv = '\0';
if (stat(path, &sbuf))
return(0);
if (!S_ISDIR(sbuf.st_mode)) {
errno = ENOTDIR;
return(0);
}
*trv = '/';
break;
}
}
for (;;) {
if (doopen) {
if ((*doopen =
open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
return(1);
if (errno != EEXIST)
return(0);
}
else if (stat(path, &sbuf))
return(errno == ENOENT ? 1 : 0);
/* tricky little algorithm for backward compatibility */
for (trv = start;;) {
if (!*trv)
return(0);
if (*trv == 'z')
*trv++ = 'a';
else {
if (isdigit(*trv))
*trv = 'a';
else
++*trv;
break;
}
}
}
/*NOTREACHED*/
}
#endif