NetBSD/usr.bin/calendar/calendar.c

734 lines
17 KiB
C

/* $NetBSD: calendar.c,v 1.53 2016/06/03 02:06:40 agc Exp $ */
/*
* Copyright (c) 1989, 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. 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1989, 1993\
The Regents of the University of California. All rights reserved.");
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)calendar.c 8.4 (Berkeley) 1/7/95";
#endif
__RCSID("$NetBSD: calendar.c,v 1.53 2016/06/03 02:06:40 agc Exp $");
#endif /* not lint */
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <assert.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <tzfile.h>
#include <unistd.h>
#include "pathnames.h"
#define CALENDAR_VERSION "calendar-20160601"
/* flags used by calendar file parser */
#define F_ISMONTH 0x01
#define F_ISDAY 0x02
#define F_ISDOW 0x04
#define F_WILDMONTH 0x10
#define F_WILDDAY 0x20
static unsigned short lookahead = 1;
static unsigned short weekend = 2;
static char *fname = NULL;
static char *datestr = NULL;
static const char *defaultnames[] = {"calendar", ".calendar", _PATH_SYSTEM_CALENDAR, NULL};
static struct passwd *pw;
static char path[MAXPATHLEN + 1];
static bool doall = false;
static bool cpp_restricted = false;
/* 1-based month, 0-based days, cumulative */
static const int daytab[][14] = {
{ 0, -1, 30, 58, 89, 119, 150, 180, 211, 242, 272, 303, 333, 364 },
{ 0, -1, 30, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
};
static struct tm *tp;
static const int *cumdays;
static int offset, yrdays;
static char dayname[10];
static struct iovec header[] = {
{ __UNCONST("From: "), 6 },
{ NULL, 0 },
{ __UNCONST(" (Reminder Service)\nTo: "), 24 },
{ NULL, 0 },
{ __UNCONST("\nSubject: "), 10 },
{ NULL, 0 },
{ __UNCONST("'s Calendar\nPrecedence: bulk\n\n"), 30 },
};
static const char *days[] = {
"sun", "mon", "tue", "wed", "thu", "fri", "sat", NULL,
};
static const char *months[] = {
"jan", "feb", "mar", "apr", "may", "jun",
"jul", "aug", "sep", "oct", "nov", "dec", NULL,
};
static void atodays(int, char *, unsigned short *);
static void cal(void);
static void closecal(FILE *);
static void changeuser(void);
static int getday(char *);
static int getfield(char *, char **, int *);
static void getmmdd(struct tm *, char *);
static int getmonth(char *);
static bool isnow(char *);
static FILE *opencal(FILE **);
static int tryopen(const char *, int);
static void settime(void);
static void usage(void) __dead;
int
main(int argc, char **argv)
{
int ch;
const char *caldir;
(void)setprogname(argv[0]); /* for portability */
while ((ch = getopt(argc, argv, "-ad:f:l:vw:x")) != -1) {
switch (ch) {
case '-': /* backward contemptible */
case 'a':
if (getuid()) {
errno = EPERM;
err(EXIT_FAILURE, NULL);
}
doall = true;
break;
case 'd':
datestr = optarg;
break;
case 'f':
fname = optarg;
break;
case 'l':
atodays(ch, optarg, &lookahead);
break;
case 'v':
printf("%s\n", CALENDAR_VERSION);
return 0;
case 'w':
atodays(ch, optarg, &weekend);
break;
case 'x':
cpp_restricted = true;
break;
case '?':
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc)
usage();
settime();
if (doall) {
/*
* XXX - This ignores the user's CALENDAR_DIR variable.
* Run under user's login shell?
*/
if (setgroups(0, NULL) == -1) {
err(EXIT_FAILURE, "setgroups");
}
while ((pw = getpwent()) != NULL) {
if (setegid(pw->pw_gid) == -1) {
warn("%s: setegid", pw->pw_name);
continue;
}
if (seteuid(pw->pw_uid) == -1) {
warn("%s: seteuid", pw->pw_name);
continue;
}
if (chdir(pw->pw_dir) != -1) {
cal();
}
if (seteuid(0) == -1) {
warn("%s: seteuid back to 0", pw->pw_name);
}
}
} else if ((caldir = getenv("CALENDAR_DIR")) != NULL) {
if (chdir(caldir) != -1)
cal();
} else if ((pw = getpwuid(geteuid())) != NULL) {
if (chdir(pw->pw_dir) != -1)
cal();
}
return 0;
}
static void
cal(void)
{
bool printing;
FILE *fp, *in = NULL;
char *line;
if ((fp = opencal(&in)) == NULL || in == NULL)
return;
printing = false;
while ((line = fparseln(in,
NULL, NULL, NULL, FPARSELN_UNESCCOMM)) != NULL) {
if (line[0] == '\0')
continue;
if (line[0] != '\t')
printing = isnow(line);
if (printing)
(void)fprintf(fp, "%s\n", line);
free(line);
}
closecal(fp);
}
static void
settime(void)
{
time_t now;
(void)time(&now);
tp = localtime(&now);
if (datestr)
getmmdd(tp, datestr);
if (isleap(tp->tm_year + TM_YEAR_BASE)) {
yrdays = DAYSPERLYEAR;
cumdays = daytab[1];
} else {
yrdays = DAYSPERNYEAR;
cumdays = daytab[0];
}
/* Friday displays Monday's events */
offset = tp->tm_wday == 5 ? lookahead + weekend : lookahead;
header[5].iov_base = dayname;
header[5].iov_len = strftime(dayname, sizeof(dayname), "%A", tp);
}
/*
* Possible date formats include any combination of:
* 3-charmonth (January, Jan, Jan)
* 3-charweekday (Friday, Monday, mon.)
* numeric month or day (1, 2, 04)
*
* Any character may separate them, or they may not be separated. Any line,
* following a line that is matched, that starts with "whitespace", is shown
* along with the matched line.
*/
static bool
isnow(char *endp)
{
int day;
int flags;
int month;
int v1;
int v2;
flags = 0;
/* didn't recognize anything, skip it */
if (!(v1 = getfield(endp, &endp, &flags)))
return false;
if ((flags & (F_ISDAY|F_ISDOW)) || v1 > 12) {
/* found a day */
day = v1;
/* if no recognizable month, assume wildcard ('*') month */
if ((month = getfield(endp, &endp, &flags)) == 0) {
flags |= F_ISMONTH | F_WILDMONTH;
month = tp->tm_mon + 1;
}
} else if (flags & F_ISMONTH) {
month = v1;
/* if no recognizable day, assume the first */
if ((day = getfield(endp, &endp, &flags)) == 0)
day = 1;
} else {
v2 = getfield(endp, &endp, &flags);
if (flags & F_ISMONTH) {
day = v1;
month = v2;
} else {
/* F_ISDAY set, v2 > 12, or no way to tell */
month = v1;
/* if no recognizable day, assume the first */
day = v2 ? v2 : 1;
}
}
/* if month is out of range, treat it as '*' */
if (month < 1 || month > 12) {
flags |= F_ISMONTH | F_WILDMONTH;
month = tp->tm_mon + 1;
}
if (flags & F_WILDMONTH && flags & F_WILDDAY)
return true;
if (flags & F_WILDMONTH && flags & F_ISDAY && day == tp->tm_mday)
return true;
if (flags & F_WILDMONTH && flags & F_ISDOW && day == tp->tm_wday + 1)
return true;
if (flags & F_ISMONTH && flags & F_WILDDAY && month == tp->tm_mon + 1)
return true;
if (flags & F_ISMONTH && flags & F_ISDOW && month == tp->tm_mon + 1 &&
day == tp->tm_wday + 1)
return true;
if (flags & F_ISDOW)
day = tp->tm_mday + (((day - 1) - tp->tm_wday + 7) % 7);
day = cumdays[month] + day;
/* if today or today + offset days */
if (day >= tp->tm_yday && day <= tp->tm_yday + offset)
return true;
/* if number of days left in this year + days to event in next year */
if (yrdays - tp->tm_yday + day <= offset)
return true;
return false;
}
static int
getfield(char *p, char **endp, int *flags)
{
int val;
char *start;
char savech;
/*
* note this macro has an arg that isn't used ... it is retained
* (it is believed) to make the macro call look more "natural"
* and suggest at the call site what is happening.
*/
#define FLDCHAR(a) (*p != '\0' && !isdigit((unsigned char)*p) && \
!isalpha((unsigned char)*p) && *p != '*')
val = 0;
for (/*EMPTY*/; FLDCHAR(*p); ++p)
continue;
if (*p == '*') { /* `*' is current month */
if (!(*flags & F_ISMONTH)) {
*flags |= F_ISMONTH | F_WILDMONTH;
*endp = p + 1;
return tp->tm_mon + 1;
} else {
*flags |= F_ISDAY | F_WILDDAY;
*endp = p + 1;
return 1;
}
}
if (isdigit((unsigned char)*p)) {
val = (int)strtol(p, &p, 10); /* if 0, it's failure */
for (/*EMPTY*/; FLDCHAR(*p); ++p)
continue;
*endp = p;
return val;
}
for (start = p; *p != '\0' && isalpha((unsigned char)*p); p++)
continue;
savech = *p;
if (p != start) {
*p = '\0';
if ((val = getmonth(start)) != 0)
*flags |= F_ISMONTH;
else if ((val = getday(start)) != 0)
*flags |= F_ISDOW;
else {
*p = savech;
*endp = start;
return 0;
}
}
for (*p = savech; FLDCHAR(*p); ++p)
continue;
*endp = p;
return val;
}
static FILE *
opencal(FILE **in)
{
int fd = -1;
int pdes[2];
/* open up calendar file as stdin */
if (fname == NULL) {
for (const char **name = defaultnames; *name != NULL; name++) {
if ((fd = tryopen(*name, O_RDONLY)) == -1)
continue;
else
break;
}
if (fd == -1) {
if (doall)
return NULL;
err(EXIT_FAILURE, "Cannot open calendar file");
}
} else if ((fd = tryopen(fname, O_RDONLY)) == -1) {
if (doall)
return NULL;
err(EXIT_FAILURE, "Cannot open `%s'", fname);
}
if (pipe(pdes) == -1) {
warn("Cannot open pipe");
return NULL;
}
switch (fork()) {
case -1:
/* error */
(void)close(pdes[0]);
(void)close(pdes[1]);
return NULL;
case 0:
/* child */
/* set stdin to calendar file */
if (fd != STDIN_FILENO) {
(void)dup2(fd, STDIN_FILENO);
(void)close(fd);
}
/* set stdout to pipe input */
if (pdes[1] != STDOUT_FILENO) {
(void)dup2(pdes[1], STDOUT_FILENO);
(void)close(pdes[1]);
}
(void)close(pdes[0]);
if (doall) {
/* become the user properly */
changeuser();
}
/* tell CPP to only open regular files */
if(!cpp_restricted && setenv("CPP_RESTRICTED", "", 1) == -1)
err(EXIT_FAILURE, "Cannot restrict cpp");
cpp_restricted = true;
(void)execl(_PATH_CPP, "cpp", "-traditional", "-P", "-I.",
"-I" _PATH_CALENDARS, NULL);
err(EXIT_FAILURE, "Cannot exec `%s'", _PATH_CPP);
/*NOTREACHED*/
default:
/* parent -- fdopen *in to pipe output */
*in = fdopen(pdes[0], "r");
(void)close(pdes[1]);
/* close calendar file */
close(fd);
/* not reading all calendar files, just set output to stdout */
if (!doall)
return stdout;
/*
* Set output to a temporary file, so if no output
* don't send mail.
*/
(void)snprintf(path, sizeof(path), "%s/_calXXXXXX", _PATH_TMP);
if ((fd = mkstemp(path)) == -1) {
warn("Cannot create temporary file");
return NULL;
}
return fdopen(fd, "w+");
}
/*NOTREACHED*/
}
static int
tryopen(const char *pathname, int flags)
{
int fd, serrno, zero;
struct stat st;
/*
* XXX: cpp_restricted has inverted sense; it is false by default,
* and -x sets it to true. CPP_RESTRICTED is set in the environment
* if cpp_restricted is false... go figure. This should be fixed
* later.
*/
if (doall && cpp_restricted == false) {
/*
* We are running with the user's euid, so they can't
* cause any mayhem (e.g. opening rewinding tape
* devices) that they couldn't do easily enough on
* their own. All we really need to worry about is opens
* that hang, because that would DoS the calendar run.
*/
fd = open(pathname, flags | O_NONBLOCK);
if (fd == -1) {
return -1;
}
if (fstat(fd, &st) == -1) {
serrno = errno;
close(fd);
errno = serrno;
return -1;
}
if (S_ISCHR(st.st_mode) ||
S_ISBLK(st.st_mode) ||
S_ISFIFO(st.st_mode)) {
close(fd);
/* Call shenanigans in the daily output */
errno = EPERM;
warn("%s: %s", pw->pw_name, pathname);
errno = EPERM;
return -1;
}
if (S_ISDIR(st.st_mode)) {
/* Don't warn about this */
close(fd);
errno = EISDIR;
return -1;
}
if (!S_ISREG(st.st_mode)) {
/* There shouldn't be other cases to go here */
close(fd);
errno = EINVAL;
return -1;
}
zero = 0;
if (ioctl(fd, FIONBIO, &zero) == -1) {
serrno = errno;
warn("%s: %s: FIONBIO", pw->pw_name, pathname);
close(fd);
errno = serrno;
return -1;
}
return fd;
} else {
return open(pathname, flags);
}
}
static void
closecal(FILE *fp)
{
struct stat sbuf;
ssize_t nread;
int pdes[2];
int status;
char buf[1024];
if (!doall)
return;
(void)rewind(fp);
if (fstat(fileno(fp), &sbuf) == -1 || sbuf.st_size == 0)
goto done;
if (pipe(pdes) == -1)
goto done;
switch (fork()) {
case -1:
/* error */
(void)close(pdes[0]);
(void)close(pdes[1]);
break;
case 0:
/* child -- set stdin to pipe output */
if (pdes[0] != STDIN_FILENO) {
(void)dup2(pdes[0], STDIN_FILENO);
(void)close(pdes[0]);
}
(void)close(pdes[1]);
if (doall) {
/* become the user properly */
changeuser();
}
(void)execl(_PATH_SENDMAIL, "sendmail", "-i", "-t", "-F",
"\"Reminder Service\"", "-f", "root", NULL);
err(EXIT_FAILURE, "Cannot exec `%s'", _PATH_SENDMAIL);
/*NOTREACHED*/
default:
/* parent -- write to pipe input */
(void)close(pdes[0]);
header[1].iov_base = header[3].iov_base = (void *)pw->pw_name;
header[1].iov_len = header[3].iov_len = strlen(pw->pw_name);
(void)writev(pdes[1], header, 7);
while ((nread = read(fileno(fp), buf, sizeof(buf))) > 0)
(void)write(pdes[1], buf, (size_t)nread);
(void)close(pdes[1]);
break;
}
done: (void)fclose(fp);
(void)unlink(path);
while (wait(&status) != -1)
continue;
}
static void
changeuser(void)
{
uid_t uid;
gid_t gid;
uid = geteuid();
gid = getegid();
assert(uid == pw->pw_uid);
assert(gid == pw->pw_gid);
if (seteuid(0) == -1) {
err(EXIT_FAILURE, "%s: changing user: cannot reassert uid 0",
pw->pw_name);
}
if (setgid(gid) == -1) {
err(EXIT_FAILURE, "%s: cannot assume gid %d",
pw->pw_name, (int)gid);
}
if (initgroups(pw->pw_name, gid) == -1) {
err(EXIT_FAILURE, "%s: cannot initgroups", pw->pw_name);
}
if (setuid(uid) == -1) {
err(EXIT_FAILURE, "%s: cannot assume uid %d",
pw->pw_name, (int)uid);
}
}
static int
getmonth(char *s)
{
const char **p;
for (p = months; *p; ++p)
if (strncasecmp(s, *p, 3) == 0)
return (int)(p - months) + 1;
return 0;
}
static int
getday(char *s)
{
const char **p;
for (p = days; *p; ++p)
if (strncasecmp(s, *p, 3) == 0)
return (int)(p - days) + 1;
return 0;
}
static void
atodays(int ch, char *arg, unsigned short *rvp)
{
int u;
u = atoi(arg);
if (u < 0 || u > 366)
warnx("-%c %d out of range 0-366, ignored.", ch, u);
else
*rvp = u;
}
#define todigit(x) ((x) - '0')
#define ATOI2(x) (todigit((x)[0]) * 10 + todigit((x)[1]))
#define ISDIG2(x) (isdigit((unsigned char)(x)[0]) && isdigit((unsigned char)(x)[1]))
static void
getmmdd(struct tm *ptm, char *ds)
{
bool ok = false;
struct tm ttm;
ttm = *ptm;
ttm.tm_isdst = -1;
if (ISDIG2(ds)) {
ttm.tm_mon = ATOI2(ds) - 1;
ds += 2;
}
if (ISDIG2(ds)) {
ttm.tm_mday = ATOI2(ds);
ds += 2;
ok = true;
}
if (ok) {
if (ISDIG2(ds) && ISDIG2(ds + 2)) {
ttm.tm_year = ATOI2(ds) * 100 - TM_YEAR_BASE;
ds += 2;
ttm.tm_year += ATOI2(ds);
} else if (ISDIG2(ds)) {
ttm.tm_year = ATOI2(ds);
if (ttm.tm_year < 69)
ttm.tm_year += 2000 - TM_YEAR_BASE;
else
ttm.tm_year += 1900 - TM_YEAR_BASE;
}
}
if (ok && mktime(&ttm) == -1)
ok = false;
if (ok)
*ptm = ttm;
else {
warnx("Can't convert `%s' to date, ignored.", ds);
usage();
}
}
__dead
static void
usage(void)
{
(void)fprintf(stderr, "usage: %s [-ax] [-d MMDD[[YY]YY]"
" [-f fname] [-l days] [-w days]\n", getprogname());
exit(1);
}