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/* $Id: utils.c,v 1.9 2001-09-07 04:21:07 rjkaes Exp $
*
* Misc. routines which are used by the various functions to handle strings
* and memory allocation and pretty much anything else we can think of. Also,
* the load cutoff routine is in here. Could not think of a better place for
* it, so it's in here.
*
* Copyright (C) 1998 Steven Young
* Copyright (C) 1999 Robert James Kaes (rjkaes@flarenet.com)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include "tinyproxy.h"
#include <ctype.h>
#include <signal.h>
#include <sysexits.h>
#include "buffer.h"
#include "log.h"
#include "sock.h"
#include "utils.h"
/*
* Display an error to the client.
*/
#define HEADER_SIZE (1024 * 8)
int httperr(struct conn_s *connptr, int err, const char *msg)
{
static char *headers = \
"HTTP/1.0 %d %s\r\n" \
"Server: %s/%s\r\n" \
"Date: %s\r\n" \
"Content-Type: text/html\r\n" \
"Content-Length: %d\r\n" \
"Connection: close\r\n" \
"\r\n";
static char *message = \
"<html><head><title>%s</title></head>\r\n" \
"<body>\r\n" \
"<font size=\"+2\">Cache Error!</font><br>\r\n" \
"An error of type %d occurred: %s\r\n" \
"<hr>\r\n" \
"<font size=\"-1\"><em>Generated by %s (%s)</em></font>\r\n" \
"</body></html>\r\n\r\n";
char *header_buffer;
char *message_buffer;
int output_size;
char timebuf[30];
time_t global_time;
header_buffer = malloc(HEADER_SIZE);
if (!header_buffer) {
log_message(LOG_ERR, "Could not allocate memory.");
return -1;
}
message_buffer = malloc(MAXBUFFSIZE);
if (!message_buffer) {
log_message(LOG_ERR, "Could not allocate memory.");
safefree(header_buffer);
return -1;
}
global_time = time(NULL);
strftime(timebuf, sizeof(timebuf), "%a, %d %b %Y %H:%M:%S GMT", gmtime(&global_time));
snprintf(message_buffer, MAXBUFFSIZE - 1, message, msg, err, msg, PACKAGE, VERSION);
snprintf(header_buffer, HEADER_SIZE - 1, headers, err, msg, PACKAGE, VERSION, timebuf, strlen(message_buffer));
output_size = strlen(message_buffer) + strlen(header_buffer);
connptr->output_message = malloc(output_size + 1);
if (!connptr->output_message) {
log_message(LOG_ERR, "Could not allocate memory.");
safefree(header_buffer);
safefree(message_buffer);
return -1;
}
strlcpy(connptr->output_message, header_buffer, output_size);
strlcat(connptr->output_message, message_buffer, output_size);
safefree(header_buffer);
safefree(message_buffer);
return 0;
}
void makedaemon(void)
{
if (fork() != 0)
exit(0);
setsid();
signal(SIGHUP, SIG_IGN);
if (fork() != 0)
exit(0);
chdir("/");
umask(077);
close(0);
close(1);
close(2);
}
/*
* Safely creates filename and returns the low-level file descriptor.
*/
static int create_file_safely(const char *filename)
{
struct stat lstatinfo;
int fildes;
/*
* lstat() the file. If it doesn't exist, create it with O_EXCL.
* If it does exist, open it for writing and perform the fstat()
* check.
*/
if (lstat(filename, &lstatinfo) < 0) {
/*
* If lstat() failed for any reason other than "file not
* existing", exit.
*/
if (errno != ENOENT) {
log_message(LOG_ERR, "Error checking PID file %s: %s.",
filename, strerror(errno));
return -1;
}
/*
* The file doesn't exist, so create it with O_EXCL to make
* sure an attacker can't slip in a file between the lstat()
* and open()
*/
if ((fildes = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600)) < 0) {
log_message(LOG_ERR, "Could not create PID file %s: %s.",
filename, strerror(errno));
return -1;
}
} else {
struct stat fstatinfo;
/*
* Open an existing file.
*/
if ((fildes = open(filename, O_RDWR)) < 0) {
log_message(LOG_ERR, "Could not open PID file %s: %s.",
filename, strerror(errno));
return -1;
}
/*
* fstat() the opened file and check that the file mode bits,
* inode, and device match.
*/
if (fstat(fildes, &fstatinfo) < 0
|| lstatinfo.st_mode != fstatinfo.st_mode
|| lstatinfo.st_ino != fstatinfo.st_ino
|| lstatinfo.st_dev != fstatinfo.st_dev) {
log_message(LOG_ERR, "The PID file %s has been changed before it could be opened.",
filename);
close(fildes);
return -1;
}
/*
* If the above check was passed, we know that the lstat()
* and fstat() were done on the same file. Now we check that
* there's only one link, and that it's a normal file (this
* isn't strictly necessary because the fstat() vs lstat()
* st_mode check would also find this)
*/
if (fstatinfo.st_nlink > 1 || !S_ISREG(lstatinfo.st_mode)) {
log_message(LOG_ERR, "The PID file %s has too many links, or is not a regular file: %s.",
filename, strerror(errno));
close(fildes);
return -1;
}
/*
* On systems whcih don't support ftruncate() the best we can
* do is to close the file and reopen it in create mode, which
* unfortunately leads to a race condition, however "systems
* which don't support ftruncate()" is pretty much SCO only,
* and if you're using that you deserve what you get.
* ("Little sympathy has been extended")
*/
#ifdef HAVE_FTRUNCATE
ftruncate(fildes, 0);
#else
close(fildes);
if ((fildes = open(filename, O_RDWR | O_CREAT | O_TRUNC, 0600)) < 0) {
log_message(LOG_ERR, "Could not open PID file %s: %s.",
filename, strerror(errno));
return -1;
}
#endif /* HAVE_FTRUNCATE */
}
return fildes;
}
/*
* Write the PID of the program to the specified file.
*/
void pidfile_create(const char *filename)
{
int fildes;
FILE *fd;
/*
* Create a new file
*/
if ((fildes = create_file_safely(filename)) < 0)
exit(1);
/*
* Open a stdio file over the low-level one.
*/
if ((fd = fdopen(fildes, "w")) == NULL) {
log_message(LOG_ERR, "fdopen() error on PID file %s: %s.",
filename, strerror(errno));
close(fildes);
unlink(filename);
exit(1);
}
fprintf(fd, "%ld\n", (long)getpid());
fclose(fd);
}
#ifndef HAVE_STRLCPY
/*
* Function API taken from OpenBSD. Like strncpy(), but does not 0 fill the
* buffer, and always NULL terminates the buffer. size is the size of the
* destination buffer.
*/
size_t strlcpy(char *dst, const char *src, size_t size)
{
size_t len = strlen(src);
size_t ret = len;
if (len >= size)
len = size - 1;
memcpy(dst, src, len);
dst[len] = '\0';
return ret;
}
#endif
#ifndef HAVE_STRLCAT
/*
* Function API taken from OpenBSD. Like strncat(), but does not 0 fill the
* buffer, and always NULL terminates the buffer. size is the length of the
* buffer, which should be one more than the maximum resulting string
* length.
*/
size_t strlcat(char *dst, const char *src, size_t size)
{
size_t len1 = strlen(dst);
size_t len2 = strlen(src);
size_t ret = len1 + len2;
if (len1 + len2 >= size)
len2 = size - len1 - 1;
if (len2 > 0) {
memcpy(dst + len1, src, len2);
dst[len1 + len2] = '\0';
}
return ret;
}
#endif
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