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freebsd-dev/usr.bin/msgs/msgs.c
Eitan Adler 50e04779c4 Check the return error of set[e][ug]id. While this can never fail in the 
current version of FreeBSD, this isn't guarenteed by the API.
Custom security modules, or future implementations of the setuid and
setgid may fail.

Submitted by:	Erik Cederstrand
Approved by:	cperciva
MFC after:	3 days
2012-10-22 03:07:05 +00:00

912 lines
19 KiB
C
Raw Blame History

/*-
* Copyright (c) 1980, 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.
* 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.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1980, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#if 0
#ifndef lint
static char sccsid[] = "@(#)msgs.c 8.2 (Berkeley) 4/28/95";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* msgs - a user bulletin board program
*
* usage:
* msgs [fhlopq] [[-]number] to read messages
* msgs -s to place messages
* msgs -c [-days] to clean up the bulletin board
*
* prompt commands are:
* y print message
* n flush message, go to next message
* q flush message, quit
* p print message, turn on 'pipe thru more' mode
* P print message, turn off 'pipe thru more' mode
* - reprint last message
* s[-][<num>] [<filename>] save message
* m[-][<num>] mail with message in temp mbox
* x exit without flushing this message
* <num> print message number <num>
*/
#define V7 /* will look for TERM in the environment */
#define OBJECT /* will object to messages without Subjects */
/* #define REJECT */ /* will reject messages without Subjects
(OBJECT must be defined also) */
/* #define UNBUFFERED *//* use unbuffered output */
#include <sys/param.h>
#include <sys/stat.h>
#include <ctype.h>
#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <locale.h>
#include <pwd.h>
#include <setjmp.h>
#include <termcap.h>
#include <termios.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "pathnames.h"
#define CMODE 0644 /* bounds file creation mode */
#define NO 0
#define YES 1
#define SUPERUSER 0 /* superuser uid */
#define DAEMON 1 /* daemon uid */
#define NLINES 24 /* default number of lines/crt screen */
#define NDAYS 21 /* default keep time for messages */
#define DAYS *24*60*60 /* seconds/day */
#define MSGSRC ".msgsrc" /* user's rc file */
#define BOUNDS "bounds" /* message bounds file */
#define NEXT "Next message? [yq]"
#define MORE "More? [ynq]"
#define NOMORE "(No more) [q] ?"
typedef char bool;
static FILE *msgsrc;
static FILE *newmsg;
static const char *sep = "-";
static char inbuf[BUFSIZ];
static char fname[MAXPATHLEN];
static char cmdbuf[MAXPATHLEN + MAXPATHLEN];
static char subj[128];
static char from[128];
static char date[128];
static char *ptr;
static char *in;
static bool local;
static bool ruptible;
static bool totty;
static bool seenfrom;
static bool seensubj;
static bool blankline;
static bool printing = NO;
static bool mailing = NO;
static bool quitit = NO;
static bool sending = NO;
static bool intrpflg = NO;
static uid_t uid;
static int msg;
static int prevmsg;
static int lct;
static int nlines;
static int Lpp = 0;
static time_t t;
static time_t keep;
/* option initialization */
static bool hdrs = NO;
static bool qopt = NO;
static bool hush = NO;
static bool send_msg = NO;
static bool locomode = NO;
static bool use_pager = NO;
static bool clean = NO;
static bool lastcmd = NO;
static jmp_buf tstpbuf;
static void ask(const char *);
static void gfrsub(FILE *);
static int linecnt(FILE *);
static int next(char *);
static char *nxtfld(char *);
static void onsusp(int);
static void onintr(int);
static void prmesg(int);
static void usage(void);
int
main(int argc, char *argv[])
{
bool newrc, already;
int rcfirst = 0; /* first message to print (from .rc) */
int rcback = 0; /* amount to back off of rcfirst */
int firstmsg = 0, nextmsg = 0, lastmsg = 0;
int blast = 0;
struct stat buf; /* stat to check access of bounds */
FILE *bounds;
char *cp;
#ifdef UNBUFFERED
setbuf(stdout, NULL);
#endif
setlocale(LC_ALL, "");
time(&t);
if (setuid(uid = getuid()) != 0)
err(1, "setuid failed");
ruptible = (signal(SIGINT, SIG_IGN) == SIG_DFL);
if (ruptible)
signal(SIGINT, SIG_DFL);
argc--, argv++;
while (argc > 0) {
if (isdigit(argv[0][0])) { /* starting message # */
rcfirst = atoi(argv[0]);
}
else if (isdigit(argv[0][1])) { /* backward offset */
rcback = atoi( &( argv[0][1] ) );
}
else {
ptr = *argv;
while (*ptr) switch (*ptr++) {
case '-':
break;
case 'c':
if (uid != SUPERUSER && uid != DAEMON)
errx(1,
"only the super-user can use the c flag");
clean = YES;
break;
case 'f': /* silently */
hush = YES;
break;
case 'h': /* headers only */
hdrs = YES;
break;
case 'l': /* local msgs only */
locomode = YES;
break;
case 'o': /* option to save last message */
lastcmd = YES;
break;
case 'p': /* pipe thru 'more' during long msgs */
use_pager = YES;
break;
case 'q': /* query only */
qopt = YES;
break;
case 's': /* sending TO msgs */
send_msg = YES;
break;
default:
usage();
}
}
argc--, argv++;
}
/*
* determine current message bounds
*/
snprintf(fname, sizeof(fname), "%s/%s", _PATH_MSGS, BOUNDS);
/*
* Test access rights to the bounds file
* This can be a little tricky. if(send_msg), then
* we will create it. We assume that if(send_msg),
* then you have write permission there.
* Else, it better be there, or we bail.
*/
if (send_msg != YES) {
if (stat(fname, &buf) < 0) {
if (hush != YES) {
err(errno, "%s", fname);
} else {
exit(1);
}
}
}
bounds = fopen(fname, "r");
if (bounds != NULL) {
fscanf(bounds, "%d %d\n", &firstmsg, &lastmsg);
fclose(bounds);
blast = lastmsg; /* save upper bound */
}
if (clean)
keep = t - (rcback? rcback : NDAYS) DAYS;
if (clean || bounds == NULL) { /* relocate message bounds */
struct dirent *dp;
struct stat stbuf;
bool seenany = NO;
DIR *dirp;
dirp = opendir(_PATH_MSGS);
if (dirp == NULL)
err(errno, "%s", _PATH_MSGS);
firstmsg = 32767;
lastmsg = 0;
for (dp = readdir(dirp); dp != NULL; dp = readdir(dirp)){
cp = dp->d_name;
int i = 0;
if (dp->d_ino == 0)
continue;
if (dp->d_namlen == 0)
continue;
if (clean)
snprintf(inbuf, sizeof(inbuf), "%s/%s", _PATH_MSGS, cp);
while (isdigit(*cp))
i = i * 10 + *cp++ - '0';
if (*cp)
continue; /* not a message! */
if (clean) {
if (stat(inbuf, &stbuf) != 0)
continue;
if (stbuf.st_mtime < keep
&& stbuf.st_mode&S_IWRITE) {
unlink(inbuf);
continue;
}
}
if (i > lastmsg)
lastmsg = i;
if (i < firstmsg)
firstmsg = i;
seenany = YES;
}
closedir(dirp);
if (!seenany) {
if (blast != 0) /* never lower the upper bound! */
lastmsg = blast;
firstmsg = lastmsg + 1;
}
else if (blast > lastmsg)
lastmsg = blast;
if (!send_msg) {
bounds = fopen(fname, "w");
if (bounds == NULL)
err(errno, "%s", fname);
chmod(fname, CMODE);
fprintf(bounds, "%d %d\n", firstmsg, lastmsg);
fclose(bounds);
}
}
if (send_msg) {
/*
* Send mode - place msgs in _PATH_MSGS
*/
bounds = fopen(fname, "w");
if (bounds == NULL)
err(errno, "%s", fname);
nextmsg = lastmsg + 1;
snprintf(fname, sizeof(fname), "%s/%d", _PATH_MSGS, nextmsg);
newmsg = fopen(fname, "w");
if (newmsg == NULL)
err(errno, "%s", fname);
chmod(fname, CMODE);
fprintf(bounds, "%d %d\n", firstmsg, nextmsg);
fclose(bounds);
sending = YES;
if (ruptible)
signal(SIGINT, onintr);
if (isatty(fileno(stdin))) {
ptr = getpwuid(uid)->pw_name;
printf("Message %d:\nFrom %s %sSubject: ",
nextmsg, ptr, ctime(&t));
fflush(stdout);
fgets(inbuf, sizeof inbuf, stdin);
putchar('\n');
fflush(stdout);
fprintf(newmsg, "From %s %sSubject: %s\n",
ptr, ctime(&t), inbuf);
blankline = seensubj = YES;
}
else
blankline = seensubj = NO;
for (;;) {
fgets(inbuf, sizeof inbuf, stdin);
if (feof(stdin) || ferror(stdin))
break;
blankline = (blankline || (inbuf[0] == '\n'));
seensubj = (seensubj || (!blankline && (strncmp(inbuf, "Subj", 4) == 0)));
fputs(inbuf, newmsg);
}
#ifdef OBJECT
if (!seensubj) {
printf("NOTICE: Messages should have a Subject field!\n");
#ifdef REJECT
unlink(fname);
#endif
exit(1);
}
#endif
exit(ferror(stdin));
}
if (clean)
exit(0);
/*
* prepare to display messages
*/
totty = (isatty(fileno(stdout)) != 0);
use_pager = use_pager && totty;
if ((cp = getenv("HOME")) == NULL || *cp == '\0') {
fprintf(stderr, "Error, no home directory!\n");
exit(1);
}
snprintf(fname, sizeof(fname), "%s/%s", cp, MSGSRC);
msgsrc = fopen(fname, "r");
if (msgsrc) {
newrc = NO;
fscanf(msgsrc, "%d\n", &nextmsg);
fclose(msgsrc);
if (nextmsg > lastmsg+1) {
printf("Warning: bounds have been reset (%d, %d)\n",
firstmsg, lastmsg);
truncate(fname, (off_t)0);
newrc = YES;
}
else if (!rcfirst)
rcfirst = nextmsg - rcback;
}
else
newrc = YES;
msgsrc = fopen(fname, "r+");
if (msgsrc == NULL)
msgsrc = fopen(fname, "w");
if (msgsrc == NULL)
err(errno, "%s", fname);
if (rcfirst) {
if (rcfirst > lastmsg+1) {
printf("Warning: the last message is number %d.\n",
lastmsg);
rcfirst = nextmsg;
}
if (rcfirst > firstmsg)
firstmsg = rcfirst; /* don't set below first msg */
}
if (newrc) {
nextmsg = firstmsg;
rewind(msgsrc);
fprintf(msgsrc, "%d\n", nextmsg);
fflush(msgsrc);
}
#ifdef V7
if (totty) {
struct winsize win;
if (ioctl(fileno(stdout), TIOCGWINSZ, &win) != -1)
Lpp = win.ws_row;
if (Lpp <= 0) {
if (tgetent(inbuf, getenv("TERM")) <= 0
|| (Lpp = tgetnum("li")) <= 0) {
Lpp = NLINES;
}
}
}
#endif
Lpp -= 6; /* for headers, etc. */
already = NO;
prevmsg = firstmsg;
printing = YES;
if (ruptible)
signal(SIGINT, onintr);
/*
* Main program loop
*/
for (msg = firstmsg; msg <= lastmsg; msg++) {
snprintf(fname, sizeof(fname), "%s/%d", _PATH_MSGS, msg);
newmsg = fopen(fname, "r");
if (newmsg == NULL)
continue;
gfrsub(newmsg); /* get From and Subject fields */
if (locomode && !local) {
fclose(newmsg);
continue;
}
if (qopt) { /* This has to be located here */
printf("There are new messages.\n");
exit(0);
}
if (already && !hdrs)
putchar('\n');
/*
* Print header
*/
if (totty)
signal(SIGTSTP, onsusp);
(void) setjmp(tstpbuf);
already = YES;
nlines = 2;
if (seenfrom) {
printf("Message %d:\nFrom %s %s", msg, from, date);
nlines++;
}
if (seensubj) {
printf("Subject: %s", subj);
nlines++;
}
else {
if (seenfrom) {
putchar('\n');
nlines++;
}
while (nlines < 6
&& fgets(inbuf, sizeof inbuf, newmsg)
&& inbuf[0] != '\n') {
fputs(inbuf, stdout);
nlines++;
}
}
lct = linecnt(newmsg);
if (lct)
printf("(%d%sline%s) ", lct, seensubj? " " : " more ",
(lct == 1) ? "" : "s");
if (hdrs) {
printf("\n-----\n");
fclose(newmsg);
continue;
}
/*
* Ask user for command
*/
if (totty)
ask(lct? MORE : (msg==lastmsg? NOMORE : NEXT));
else
inbuf[0] = 'y';
if (totty)
signal(SIGTSTP, SIG_DFL);
cmnd:
in = inbuf;
switch (*in) {
case 'x':
/* FALLTHROUGH */
case 'X':
exit(0);
/* NOTREACHED */
case 'q':
/* FALLTHROUGH */
case 'Q':
quitit = YES;
printf("--Postponed--\n");
exit(0);
/* NOTREACHED */
case 'n':
/* FALLTHROUGH */
case 'N':
if (msg >= nextmsg) sep = "Flushed";
prevmsg = msg;
break;
case 'p':
/* FALLTHROUGH */
case 'P':
use_pager = (*in++ == 'p');
/* FALLTHROUGH */
case '\n':
/* FALLTHROUGH */
case 'y':
default:
if (*in == '-') {
msg = prevmsg-1;
sep = "replay";
break;
}
if (isdigit(*in)) {
msg = next(in);
sep = in;
break;
}
prmesg(nlines + lct + (seensubj? 1 : 0));
prevmsg = msg;
}
printf("--%s--\n", sep);
sep = "-";
if (msg >= nextmsg) {
nextmsg = msg + 1;
rewind(msgsrc);
fprintf(msgsrc, "%d\n", nextmsg);
fflush(msgsrc);
}
if (newmsg)
fclose(newmsg);
if (quitit)
break;
}
/*
* Make sure .rc file gets updated
*/
if (--msg >= nextmsg) {
nextmsg = msg + 1;
rewind(msgsrc);
fprintf(msgsrc, "%d\n", nextmsg);
fflush(msgsrc);
}
if (already && !quitit && lastcmd && totty) {
/*
* save or reply to last message?
*/
msg = prevmsg;
ask(NOMORE);
if (inbuf[0] == '-' || isdigit(inbuf[0]))
goto cmnd;
}
if (!(already || hush || qopt))
printf("No new messages.\n");
exit(0);
/* NOTREACHED */
}
static void
usage(void)
{
fprintf(stderr, "usage: msgs [fhlopq] [[-]number]\n");
exit(1);
}
static void
prmesg(int length)
{
FILE *outf;
char *env_pager;
if (use_pager && length > Lpp) {
signal(SIGPIPE, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
if ((env_pager = getenv("PAGER")) == NULL) {
snprintf(cmdbuf, sizeof(cmdbuf), _PATH_PAGER, Lpp);
} else {
snprintf(cmdbuf, sizeof(cmdbuf), "%s", env_pager);
}
outf = popen(cmdbuf, "w");
if (!outf)
outf = stdout;
else
setbuf(outf, (char *)NULL);
}
else
outf = stdout;
if (seensubj)
putc('\n', outf);
while (fgets(inbuf, sizeof inbuf, newmsg)) {
fputs(inbuf, outf);
if (ferror(outf)) {
clearerr(outf);
break;
}
}
if (outf != stdout) {
pclose(outf);
signal(SIGPIPE, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
}
else {
fflush(stdout);
}
/* force wait on output */
tcdrain(fileno(stdout));
}
static void
onintr(int unused __unused)
{
signal(SIGINT, onintr);
if (mailing)
unlink(fname);
if (sending) {
unlink(fname);
puts("--Killed--");
exit(1);
}
if (printing) {
putchar('\n');
if (hdrs)
exit(0);
sep = "Interrupt";
if (newmsg)
fseeko(newmsg, (off_t)0, SEEK_END);
intrpflg = YES;
}
}
/*
* We have just gotten a susp. Suspend and prepare to resume.
*/
static void
onsusp(int unused __unused)
{
signal(SIGTSTP, SIG_DFL);
sigsetmask(0);
kill(0, SIGTSTP);
signal(SIGTSTP, onsusp);
if (!mailing)
longjmp(tstpbuf, 0);
}
static int
linecnt(FILE *f)
{
off_t oldpos = ftello(f);
int l = 0;
char lbuf[BUFSIZ];
while (fgets(lbuf, sizeof lbuf, f))
l++;
clearerr(f);
fseeko(f, oldpos, SEEK_SET);
return (l);
}
static int
next(char *buf)
{
int i;
sscanf(buf, "%d", &i);
sprintf(buf, "Goto %d", i);
return(--i);
}
static void
ask(const char *prompt)
{
char inch;
int n, cmsg, fd;
off_t oldpos;
FILE *cpfrom, *cpto;
printf("%s ", prompt);
fflush(stdout);
intrpflg = NO;
(void) fgets(inbuf, sizeof inbuf, stdin);
if ((n = strlen(inbuf)) > 0 && inbuf[n - 1] == '\n')
inbuf[n - 1] = '\0';
if (intrpflg)
inbuf[0] = 'x';
/*
* Handle 'mail' and 'save' here.
*/
if ((inch = inbuf[0]) == 's' || inch == 'm') {
if (inbuf[1] == '-')
cmsg = prevmsg;
else if (isdigit(inbuf[1]))
cmsg = atoi(&inbuf[1]);
else
cmsg = msg;
snprintf(fname, sizeof(fname), "%s/%d", _PATH_MSGS, cmsg);
oldpos = ftello(newmsg);
cpfrom = fopen(fname, "r");
if (!cpfrom) {
printf("Message %d not found\n", cmsg);
ask (prompt);
return;
}
if (inch == 's') {
in = nxtfld(inbuf);
if (*in) {
for (n=0; in[n] > ' '; n++) { /* sizeof fname? */
fname[n] = in[n];
}
fname[n] = '\0';
}
else
strcpy(fname, "Messages");
fd = open(fname, O_RDWR|O_EXCL|O_CREAT|O_APPEND);
}
else {
strcpy(fname, _PATH_TMP);
fd = mkstemp(fname);
if (fd != -1) {
snprintf(cmdbuf, sizeof(cmdbuf), _PATH_MAIL,
fname);
mailing = YES;
}
}
if (fd == -1 || (cpto = fdopen(fd, "a")) == NULL) {
if (fd != -1)
close(fd);
warn("%s", fname);
mailing = NO;
fseeko(newmsg, oldpos, SEEK_SET);
ask(prompt);
return;
}
while ((n = fread(inbuf, 1, sizeof inbuf, cpfrom)))
fwrite(inbuf, 1, n, cpto);
fclose(cpfrom);
fclose(cpto);
fseeko(newmsg, oldpos, SEEK_SET);/* reposition current message */
if (inch == 's')
printf("Message %d saved in \"%s\"\n", cmsg, fname);
else {
system(cmdbuf);
unlink(fname);
mailing = NO;
}
ask(prompt);
}
}
static void
gfrsub(FILE *infile)
{
off_t frompos;
int count;
seensubj = seenfrom = NO;
local = YES;
subj[0] = from[0] = date[0] = '\0';
/*
* Is this a normal message?
*/
if (fgets(inbuf, sizeof inbuf, infile)) {
if (strncmp(inbuf, "From", 4)==0) {
/*
* expected form starts with From
*/
seenfrom = YES;
frompos = ftello(infile);
ptr = from;
in = nxtfld(inbuf);
if (*in) {
count = sizeof(from) - 1;
while (*in && *in > ' ' && count-- > 0) {
if (*in == ':' || *in == '@' ||
*in == '!')
local = NO;
*ptr++ = *in++;
}
}
*ptr = '\0';
if (*(in = nxtfld(in)))
strncpy(date, in, sizeof date);
else {
date[0] = '\n';
date[1] = '\0';
}
}
else {
/*
* not the expected form
*/
rewind(infile);
return;
}
}
else
/*
* empty file ?
*/
return;
/*
* look for Subject line until EOF or a blank line
*/
while (fgets(inbuf, sizeof inbuf, infile)
&& !(blankline = (inbuf[0] == '\n'))) {
/*
* extract Subject line
*/
if (!seensubj && strncmp(inbuf, "Subj", 4)==0) {
seensubj = YES;
frompos = ftello(infile);
strncpy(subj, nxtfld(inbuf), sizeof subj);
}
}
if (!blankline)
/*
* ran into EOF
*/
fseeko(infile, frompos, SEEK_SET);
if (!seensubj)
/*
* for possible use with Mail
*/
strncpy(subj, "(No Subject)\n", sizeof subj);
}
static char *
nxtfld(char *s)
{
if (*s) while (*s && !isspace(*s)) s++; /* skip over this field */
if (*s) while (*s && isspace(*s)) s++; /* find start of next field */
return (s);
}
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