/*
* utils.c - various utility functions used in pppd.
*
* Copyright (c) 1999-2002 Paul Mackerras. 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. The name(s) of the authors of this software must not be used to
* endorse or promote products derived from this software without
* prior written permission.
*
* 3. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by Paul Mackerras
* <paulus@samba.org>".
*
* THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
* THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#define RCSID "$Id: utils.c,v 1.25 2008/06/03 12:06:37 paulus Exp $"
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <syslog.h>
#include <netdb.h>
#include <time.h>
#include <utmp.h>
#include <pwd.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#ifdef SVR4
#include <sys/mkdev.h>
#endif
#include "pppd.h"
#include "fsm.h"
#include "lcp.h"
static const char rcsid[] = RCSID;
#if defined(SUNOS4)
extern char *strerror();
#endif
static void logit __P((int, char *, va_list));
static void log_write __P((int, char *));
static void vslp_printer __P((void *, char *, ...));
static void format_packet __P((u_char *, int, printer_func, void *));
struct buffer_info {
char *ptr;
int len;
};
#if !defined(__ANDROID__)
/*
* strlcpy - like strcpy/strncpy, doesn't overflow destination buffer,
* always leaves destination null-terminated (for len > 0).
*/
size_t
strlcpy(dest, src, len)
char *dest;
const char *src;
size_t len;
{
size_t ret = strlen(src);
if (len != 0) {
if (ret < len)
strcpy(dest, src);
else {
strncpy(dest, src, len - 1);
dest[len-1] = 0;
}
}
return ret;
}
/*
* strlcat - like strcat/strncat, doesn't overflow destination buffer,
* always leaves destination null-terminated (for len > 0).
*/
size_t
strlcat(dest, src, len)
char *dest;
const char *src;
size_t len;
{
size_t dlen = strlen(dest);
return dlen + strlcpy(dest + dlen, src, (len > dlen? len - dlen: 0));
}
#endif
/*
* slprintf - format a message into a buffer. Like sprintf except we
* also specify the length of the output buffer, and we handle
* %m (error message), %v (visible string),
* %q (quoted string), %t (current time) and %I (IP address) formats.
* Doesn't do floating-point formats.
* Returns the number of chars put into buf.
*/
int
slprintf __V((char *buf, int buflen, char *fmt, ...))
{
va_list args;
int n;
#if defined(__STDC__)
va_start(args, fmt);
#else
char *buf;
int buflen;
char *fmt;
va_start(args);
buf = va_arg(args, char *);
buflen = va_arg(args, int);
fmt = va_arg(args, char *);
#endif
n = vslprintf(buf, buflen, fmt, args);
va_end(args);
return n;
}
/*
* vslprintf - like slprintf, takes a va_list instead of a list of args.
*/
#define OUTCHAR(c) (buflen > 0? (--buflen, *buf++ = (c)): 0)
int
vslprintf(buf, buflen, fmt, args)
char *buf;
int buflen;
char *fmt;
va_list args;
{
int c, i, n;
int width, prec, fillch;
int base, len, neg, quoted;
unsigned long val = 0;
char *str, *f, *buf0;
unsigned char *p;
char num[32];
time_t t;
u_int32_t ip;
static char hexchars[] = "0123456789abcdef";
struct buffer_info bufinfo;
buf0 = buf;
--buflen;
while (buflen > 0) {
for (f = fmt; *f != '%' && *f != 0; ++f)
;
if (f > fmt) {
len = f - fmt;
if (len > buflen)
len = buflen;
memcpy(buf, fmt, len);
buf += len;
buflen -= len;
fmt = f;
}
if (*fmt == 0)
break;
c = *++fmt;
width = 0;
prec = -1;
fillch = ' ';
if (c == '0') {
fillch = '0';
c = *++fmt;
}
if (c == '*') {
width = va_arg(args, int);
c = *++fmt;
} else {
while (isdigit(c)) {
width = width * 10 + c - '0';
c = *++fmt;
}
}
if (c == '.') {
c = *++fmt;
if (c == '*') {
prec = va_arg(args, int);
c = *++fmt;
} else {
prec = 0;
while (isdigit(c)) {
prec = prec * 10 + c - '0';
c = *++fmt;
}
}
}
str = 0;
base = 0;
neg = 0;
++fmt;
switch (c) {
case 'l':
c = *fmt++;
switch (c) {
case 'd':
val = va_arg(args, long);
#if defined(__ANDROID__)
if ((long)val < 0) {
neg = 1;
val = (unsigned long)(-(long)val);
}
#else
if (val < 0) {
neg = 1;
val = -val;
}
#endif
base = 10;
break;
case 'u':
val = va_arg(args, unsigned long);
base = 10;
break;
default:
OUTCHAR('%');
OUTCHAR('l');
--fmt; /* so %lz outputs %lz etc. */
continue;
}
break;
case 'd':
i = va_arg(args, int);
if (i < 0) {
neg = 1;
val = -i;
} else
val = i;
base = 10;
break;
case 'u':
val = va_arg(args, unsigned int);
base = 10;
break;
case 'o':
val = va_arg(args, unsigned int);
base = 8;
break;
case 'x':
case 'X':
val = va_arg(args, unsigned int);
base = 16;
break;
case 'p':
val = (unsigned long) va_arg(args, void *);
base = 16;
neg = 2;
break;
case 's':
str = va_arg(args, char *);
break;
case 'c':
num[0] = va_arg(args, int);
num[1] = 0;
str = num;
break;
case 'm':
str = strerror(errno);
break;
case 'I':
ip = va_arg(args, u_int32_t);
ip = ntohl(ip);
slprintf(num, sizeof(num), "%d.%d.%d.%d", (ip >> 24) & 0xff,
(ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
str = num;
break;
case 't':
time(&t);
str = ctime(&t);
str += 4; /* chop off the day name */
str[15] = 0; /* chop off year and newline */
break;
case 'v': /* "visible" string */
case 'q': /* quoted string */
quoted = c == 'q';
p = va_arg(args, unsigned char *);
if (p == NULL)
p = (unsigned char *)"<NULL>";
if (fillch == '0' && prec >= 0) {
n = prec;
} else {
n = strlen((char *)p);
if (prec >= 0 && n > prec)
n = prec;
}
while (n > 0 && buflen > 0) {
c = *p++;
--n;
if (!quoted && c >= 0x80) {
OUTCHAR('M');
OUTCHAR('-');
c -= 0x80;
}
if (quoted && (c == '"' || c == '\\'))
OUTCHAR('\\');
if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
if (quoted) {
OUTCHAR('\\');
switch (c) {
case '\t': OUTCHAR('t'); break;
case '\n': OUTCHAR('n'); break;
case '\b': OUTCHAR('b'); break;
case '\f': OUTCHAR('f'); break;
default:
OUTCHAR('x');
OUTCHAR(hexchars[c >> 4]);
OUTCHAR(hexchars[c & 0xf]);
}
} else {
if (c == '\t')
OUTCHAR(c);
else {
OUTCHAR('^');
OUTCHAR(c ^ 0x40);
}
}
} else
OUTCHAR(c);
}
continue;
case 'P': /* print PPP packet */
bufinfo.ptr = buf;
bufinfo.len = buflen + 1;
p = va_arg(args, unsigned char *);
n = va_arg(args, int);
format_packet(p, n, vslp_printer, &bufinfo);
buf = bufinfo.ptr;
buflen = bufinfo.len - 1;
continue;
case 'B':
p = va_arg(args, unsigned char *);
for (n = prec; n > 0; --n) {
c = *p++;
if (fillch == ' ')
OUTCHAR(' ');
OUTCHAR(hexchars[(c >> 4) & 0xf]);
OUTCHAR(hexchars[c & 0xf]);
}
continue;
default:
*buf++ = '%';
if (c != '%')
--fmt; /* so %z outputs %z etc. */
--buflen;
continue;
}
if (base != 0) {
str = num + sizeof(num);
*--str = 0;
while (str > num + neg) {
*--str = hexchars[val % base];
val = val / base;
if (--prec <= 0 && val == 0)
break;
}
switch (neg) {
case 1:
*--str = '-';
break;
case 2:
*--str = 'x';
*--str = '0';
break;
}
len = num + sizeof(num) - 1 - str;
} else {
len = strlen(str);
if (prec >= 0 && len > prec)
len = prec;
}
if (width > 0) {
if (width > buflen)
width = buflen;
if ((n = width - len) > 0) {
buflen -= n;
for (; n > 0; --n)
*buf++ = fillch;
}
}
if (len > buflen)
len = buflen;
memcpy(buf, str, len);
buf += len;
buflen -= len;
}
*buf = 0;
return buf - buf0;
}
/*
* vslp_printer - used in processing a %P format
*/
static void
vslp_printer __V((void *arg, char *fmt, ...))
{
int n;
va_list pvar;
struct buffer_info *bi;
#if defined(__STDC__)
va_start(pvar, fmt);
#else
void *arg;
char *fmt;
va_start(pvar);
arg = va_arg(pvar, void *);
fmt = va_arg(pvar, char *);
#endif
bi = (struct buffer_info *) arg;
n = vslprintf(bi->ptr, bi->len, fmt, pvar);
va_end(pvar);
bi->ptr += n;
bi->len -= n;
}
#ifdef unused
/*
* log_packet - format a packet and log it.
*/
void
log_packet(p, len, prefix, level)
u_char *p;
int len;
char *prefix;
int level;
{
init_pr_log(prefix, level);
format_packet(p, len, pr_log, &level);
end_pr_log();
}
#endif /* unused */
/*
* format_packet - make a readable representation of a packet,
* calling `printer(arg, format, ...)' to output it.
*/
static void
format_packet(p, len, printer, arg)
u_char *p;
int len;
printer_func printer;
void *arg;
{
int i, n;
u_short proto;
struct protent *protp;
if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
p += 2;
GETSHORT(proto, p);
len -= PPP_HDRLEN;
for (i = 0; (protp = protocols[i]) != NULL; ++i)
if (proto == protp->protocol)
break;
if (protp != NULL) {
printer(arg, "[%s", protp->name);
n = (*protp->printpkt)(p, len, printer, arg);
printer(arg, "]");
p += n;
len -= n;
} else {
for (i = 0; (protp = protocols[i]) != NULL; ++i)
if (proto == (protp->protocol & ~0x8000))
break;
if (protp != 0 && protp->data_name != 0) {
printer(arg, "[%s data]", protp->data_name);
if (len > 8)
printer(arg, "%.8B ...", p);
else
printer(arg, "%.*B", len, p);
len = 0;
} else
printer(arg, "[proto=0x%x]", proto);
}
}
if (len > 32)
printer(arg, "%.32B ...", p);
else
printer(arg, "%.*B", len, p);
}
/*
* init_pr_log, end_pr_log - initialize and finish use of pr_log.
*/
static char line[256]; /* line to be logged accumulated here */
static char *linep; /* current pointer within line */
static int llevel; /* level for logging */
void
init_pr_log(prefix, level)
const char *prefix;
int level;
{
linep = line;
if (prefix != NULL) {
strlcpy(line, prefix, sizeof(line));
linep = line + strlen(line);
}
llevel = level;
}
void
end_pr_log()
{
if (linep != line) {
*linep = 0;
log_write(llevel, line);
}
}
/*
* pr_log - printer routine for outputting to syslog
*/
void
pr_log __V((void *arg, char *fmt, ...))
{
int l, n;
va_list pvar;
char *p, *eol;
char buf[256];
#if defined(__STDC__)
va_start(pvar, fmt);
#else
void *arg;
char *fmt;
va_start(pvar);
arg = va_arg(pvar, void *);
fmt = va_arg(pvar, char *);
#endif
n = vslprintf(buf, sizeof(buf), fmt, pvar);
va_end(pvar);
p = buf;
eol = strchr(buf, '\n');
if (linep != line) {
l = (eol == NULL)? n: eol - buf;
if (linep + l < line + sizeof(line)) {
if (l > 0) {
memcpy(linep, buf, l);
linep += l;
}
if (eol == NULL)
return;
p = eol + 1;
eol = strchr(p, '\n');
}
*linep = 0;
log_write(llevel, line);
linep = line;
}
while (eol != NULL) {
*eol = 0;
log_write(llevel, p);
p = eol + 1;
eol = strchr(p, '\n');
}
/* assumes sizeof(buf) <= sizeof(line) */
l = buf + n - p;
if (l > 0) {
memcpy(line, p, n);
linep = line + l;
}
}
/*
* print_string - print a readable representation of a string using
* printer.
*/
void
print_string(p, len, printer, arg)
char *p;
int len;
printer_func printer;
void *arg;
{
int c;
printer(arg, "\"");
for (; len > 0; --len) {
c = *p++;
if (' ' <= c && c <= '~') {
if (c == '\\' || c == '"')
printer(arg, "\\");
printer(arg, "%c", c);
} else {
switch (c) {
case '\n':
printer(arg, "\\n");
break;
case '\r':
printer(arg, "\\r");
break;
case '\t':
printer(arg, "\\t");
break;
default:
printer(arg, "\\%.3o", c);
}
}
}
printer(arg, "\"");
}
/*
* logit - does the hard work for fatal et al.
*/
static void
logit(level, fmt, args)
int level;
char *fmt;
va_list args;
{
char buf[1024];
vslprintf(buf, sizeof(buf), fmt, args);
log_write(level, buf);
}
static void
log_write(level, buf)
int level;
char *buf;
{
syslog(level, "%s", buf);
if (log_to_fd >= 0 && (level != LOG_DEBUG || debug)) {
int n = strlen(buf);
if (n > 0 && buf[n-1] == '\n')
--n;
if (write(log_to_fd, buf, n) != n
|| write(log_to_fd, "\n", 1) != 1)
log_to_fd = -1;
}
}
/*
* fatal - log an error message and die horribly.
*/
void
fatal __V((char *fmt, ...))
{
va_list pvar;
#if defined(__STDC__)
va_start(pvar, fmt);
#else
char *fmt;
va_start(pvar);
fmt = va_arg(pvar, char *);
#endif
logit(LOG_ERR, fmt, pvar);
va_end(pvar);
die(1); /* as promised */
}
/*
* error - log an error message.
*/
void
error __V((char *fmt, ...))
{
va_list pvar;
#if defined(__STDC__)
va_start(pvar, fmt);
#else
char *fmt;
va_start(pvar);
fmt = va_arg(pvar, char *);
#endif
logit(LOG_ERR, fmt, pvar);
va_end(pvar);
++error_count;
}
/*
* warn - log a warning message.
*/
void
warn __V((char *fmt, ...))
{
va_list pvar;
#if defined(__STDC__)
va_start(pvar, fmt);
#else
char *fmt;
va_start(pvar);
fmt = va_arg(pvar, char *);
#endif
logit(LOG_WARNING, fmt, pvar);
va_end(pvar);
}
/*
* notice - log a notice-level message.
*/
void
notice __V((char *fmt, ...))
{
va_list pvar;
#if defined(__STDC__)
va_start(pvar, fmt);
#else
char *fmt;
va_start(pvar);
fmt = va_arg(pvar, char *);
#endif
logit(LOG_NOTICE, fmt, pvar);
va_end(pvar);
}
/*
* info - log an informational message.
*/
void
info __V((char *fmt, ...))
{
va_list pvar;
#if defined(__STDC__)
va_start(pvar, fmt);
#else
char *fmt;
va_start(pvar);
fmt = va_arg(pvar, char *);
#endif
logit(LOG_INFO, fmt, pvar);
va_end(pvar);
}
/*
* dbglog - log a debug message.
*/
void
dbglog __V((char *fmt, ...))
{
va_list pvar;
#if defined(__STDC__)
va_start(pvar, fmt);
#else
char *fmt;
va_start(pvar);
fmt = va_arg(pvar, char *);
#endif
logit(LOG_DEBUG, fmt, pvar);
va_end(pvar);
}
/*
* dump_packet - print out a packet in readable form if it is interesting.
* Assumes len >= PPP_HDRLEN.
*/
void
dump_packet(const char *tag, unsigned char *p, int len)
{
int proto;
if (!debug)
return;
/*
* don't print LCP echo request/reply packets if debug <= 1
* and the link is up.
*/
proto = (p[2] << 8) + p[3];
if (debug <= 1 && unsuccess == 0 && proto == PPP_LCP
&& len >= PPP_HDRLEN + HEADERLEN) {
unsigned char *lcp = p + PPP_HDRLEN;
int l = (lcp[2] << 8) + lcp[3];
if ((lcp[0] == ECHOREQ || lcp[0] == ECHOREP)
&& l >= HEADERLEN && l <= len - PPP_HDRLEN)
return;
}
dbglog("%s %P", tag, p, len);
}
/*
* complete_read - read a full `count' bytes from fd,
* unless end-of-file or an error other than EINTR is encountered.
*/
ssize_t
complete_read(int fd, void *buf, size_t count)
{
size_t done;
ssize_t nb;
char *ptr = buf;
for (done = 0; done < count; ) {
nb = read(fd, ptr, count - done);
if (nb < 0) {
if (errno == EINTR)
continue;
return -1;
}
if (nb == 0)
break;
done += nb;
ptr += nb;
}
return done;
}
/* Procedures for locking the serial device using a lock file. */
#ifndef LOCK_DIR
#ifdef __linux__
#define LOCK_DIR "/var/lock"
#else
#ifdef SVR4
#define LOCK_DIR "/var/spool/locks"
#else
#define LOCK_DIR "/var/spool/lock"
#endif
#endif
#endif /* LOCK_DIR */
static char lock_file[MAXPATHLEN];
/*
* lock - create a lock file for the named device
*/
int
lock(dev)
char *dev;
{
#ifdef LOCKLIB
int result;
result = mklock (dev, (void *) 0);
if (result == 0) {
strlcpy(lock_file, dev, sizeof(lock_file));
return 0;
}
if (result > 0)
notice("Device %s is locked by pid %d", dev, result);
else
error("Can't create lock file %s", lock_file);
return -1;
#else /* LOCKLIB */
char lock_buffer[12];
int fd, pid, n;
#ifdef SVR4
struct stat sbuf;
if (stat(dev, &sbuf) < 0) {
error("Can't get device number for %s: %m", dev);
return -1;
}
if ((sbuf.st_mode & S_IFMT) != S_IFCHR) {
error("Can't lock %s: not a character device", dev);
return -1;
}
slprintf(lock_file, sizeof(lock_file), "%s/LK.%03d.%03d.%03d",
LOCK_DIR, major(sbuf.st_dev),
major(sbuf.st_rdev), minor(sbuf.st_rdev));
#else
char *p;
char lockdev[MAXPATHLEN];
if ((p = strstr(dev, "dev/")) != NULL) {
dev = p + 4;
strncpy(lockdev, dev, MAXPATHLEN-1);
lockdev[MAXPATHLEN-1] = 0;
while ((p = strrchr(lockdev, '/')) != NULL) {
*p = '_';
}
dev = lockdev;
} else
if ((p = strrchr(dev, '/')) != NULL)
dev = p + 1;
slprintf(lock_file, sizeof(lock_file), "%s/LCK..%s", LOCK_DIR, dev);
#endif
while ((fd = open(lock_file, O_EXCL | O_CREAT | O_RDWR, 0644)) < 0) {
if (errno != EEXIST) {
error("Can't create lock file %s: %m", lock_file);
break;
}
/* Read the lock file to find out who has the device locked. */
fd = open(lock_file, O_RDONLY, 0);
if (fd < 0) {
if (errno == ENOENT) /* This is just a timing problem. */
continue;
error("Can't open existing lock file %s: %m", lock_file);
break;
}
#ifndef LOCK_BINARY
n = read(fd, lock_buffer, 11);
#else
n = read(fd, &pid, sizeof(pid));
#endif /* LOCK_BINARY */
close(fd);
fd = -1;
if (n <= 0) {
error("Can't read pid from lock file %s", lock_file);
break;
}
/* See if the process still exists. */
#ifndef LOCK_BINARY
lock_buffer[n] = 0;
pid = atoi(lock_buffer);
#endif /* LOCK_BINARY */
if (pid == getpid())
return 1; /* somebody else locked it for us */
if (pid == 0
|| (kill(pid, 0) == -1 && errno == ESRCH)) {
if (unlink (lock_file) == 0) {
notice("Removed stale lock on %s (pid %d)", dev, pid);
continue;
}
warn("Couldn't remove stale lock on %s", dev);
} else
notice("Device %s is locked by pid %d", dev, pid);
break;
}
if (fd < 0) {
lock_file[0] = 0;
return -1;
}
pid = getpid();
#ifndef LOCK_BINARY
slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
write (fd, lock_buffer, 11);
#else
write(fd, &pid, sizeof (pid));
#endif
close(fd);
return 0;
#endif
}
/*
* relock - called to update our lockfile when we are about to detach,
* thus changing our pid (we fork, the child carries on, and the parent dies).
* Note that this is called by the parent, with pid equal to the pid
* of the child. This avoids a potential race which would exist if
* we had the child rewrite the lockfile (the parent might die first,
* and another process could think the lock was stale if it checked
* between when the parent died and the child rewrote the lockfile).
*/
int
relock(pid)
int pid;
{
#ifdef LOCKLIB
/* XXX is there a way to do this? */
return -1;
#else /* LOCKLIB */
int fd;
char lock_buffer[12];
if (lock_file[0] == 0)
return -1;
fd = open(lock_file, O_WRONLY, 0);
if (fd < 0) {
error("Couldn't reopen lock file %s: %m", lock_file);
lock_file[0] = 0;
return -1;
}
#ifndef LOCK_BINARY
slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
write (fd, lock_buffer, 11);
#else
write(fd, &pid, sizeof(pid));
#endif /* LOCK_BINARY */
close(fd);
return 0;
#endif /* LOCKLIB */
}
/*
* unlock - remove our lockfile
*/
void
unlock()
{
if (lock_file[0]) {
#ifdef LOCKLIB
(void) rmlock(lock_file, (void *) 0);
#else
unlink(lock_file);
#endif
lock_file[0] = 0;
}
}