libhttpd.c

修改后的thttp

/* libhttpd.c - HTTP protocol library
**
** Copyright (C)1995,1998 by Jef Poskanzer <[e-mail]>. 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.
** 
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 "config.h"
#include "version.h"

#include <sys/types.h>
#include <sys/param.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>

#ifdef HAVE_DIRENT_H
# include <dirent.h>
# define NAMLEN(dirent) strlen((dirent)->d_name)
#else
# define dirent direct
# define NAMLEN(dirent) (dirent)->d_namlen
# ifdef HAVE_SYS_NDIR_H
#  include <sys/ndir.h>
# endif
# ifdef HAVE_SYS_DIR_H
#  include <sys/dir.h>
# endif
# ifdef HAVE_NDIR_H
#  include <ndir.h>
# endif
#endif

extern char* crypt( const char* key, const char* setting );

#include "libhttpd.h"
#include "mmc.h"
#include "timers.h"
#include "match.h"
#include "tdate_parse.h"

#ifndef STDIN_FILENO
#define STDIN_FILENO 0
#endif
#ifndef STDOUT_FILENO
#define STDOUT_FILENO 1
#endif
#ifndef STDERR_FILENO
#define STDERR_FILENO 2
#endif

#ifndef max
#define max(a,b) ((a) > (b) ? (a) : (b))
#endif
#ifndef min
#define min(a,b) ((a) < (b) ? (a) : (b))
#endif

static const char* rfc1123fmt = "%a, %d %b %Y %H:%M:%S GMT";
static const char* cernfmt = "%d/%b/%Y:%H:%M:%S %Z";


/* Forwards. */
static void child_reaper( ClientData client_data, struct timeval* nowP );
static int do_reap( void );
static void check_options( void );
static void free_httpd_server( httpd_server* hs );
static void add_response( httpd_conn* hc, char* str );
static void send_mime( httpd_conn* hc, int status, char* title, char* encodings, char* extraheads, char* type, int length, time_t mod );
static void realloc_str( char** strP, int* maxsizeP, int size );
static void send_response( httpd_conn* hc, int status, char* title, char* extrahead, char* form, char* arg );
#ifdef AUTH_FILE
static void send_authenticate( httpd_conn* hc, char* realm );
static int b64_decode( const char* str, unsigned char* space, int size );
static int auth_check( httpd_conn* hc, char* dirname  );
#endif /* AUTH_FILE */
static void send_dirredirect( httpd_conn* hc );
static int is_hexit( char c );
static int hexit( char c );
static void strdecode( char* to, char* from );
static int tilde_map( httpd_conn* hc );
static char* expand_symlinks( char* path, char** restP, int chrooted );
static char* bufgets( httpd_conn* hc );
static void figure_mime( httpd_conn* hc );
static void cgi_kill2( ClientData client_data, struct timeval* nowP );
static void cgi_kill( ClientData client_data, struct timeval* nowP );
#ifdef GENERATE_INDEXES
static off_t ls( httpd_conn* hc );
#endif /* GENERATE_INDEXES */
static char* build_env( char* fmt, char* arg );
#ifdef SERVER_NAME_LIST
static char* hostname_map( char* hostname );
#endif /* SERVER_NAME_LIST */
static char** make_envp( httpd_conn* hc );
static char** make_argp( httpd_conn* hc );
static void cgi_interpose( httpd_conn* hc, int wfd );
static void cgi_child( httpd_conn* hc );
static off_t cgi( httpd_conn* hc );
static int really_start_request( httpd_conn* hc );


static int reap_time;

static void
child_reaper( ClientData client_data, struct timeval* nowP )
    {
    int child_count;
    static int prev_child_count = 0;

    child_count = do_reap();

    /* Reschedule reaping, with adaptively changed time. */
    if ( child_count > prev_child_count * 3 / 2 )
	reap_time = max( reap_time / 2, MIN_REAP_TIME );
    else if ( child_count < prev_child_count * 2 / 3 )
	reap_time = min( reap_time * 5 / 4, MAX_REAP_TIME );
    (void) tmr_create(
	nowP, child_reaper, (ClientData) 0, reap_time * 1000L, 0 );
    }

static int
do_reap( void )
    {
    int child_count;
    pid_t pid;
    int status;

    /* Reap defunct children until there aren't any more. */
    for ( child_count = 0; ; ++child_count )
	{
#ifdef HAVE_WAITPID
	pid = waitpid( (pid_t) -1, &status, WNOHANG );
#else /* HAVE_WAITPID */
	pid = wait3( &status, WNOHANG, (struct rusage*) 0 );
#endif /* HAVE_WAITPID */
	if ( (int) pid == 0 )		/* none left */
	    break;
	if ( (int) pid < 0 )
	    {
	    if ( errno == EINTR )	/* because of ptrace */
		continue;
	    /* ECHILD shouldn't happen with the WNOHANG option, but with
	    ** some kernels it does anyway.  Ignore it.
	    */
	    if ( errno != ECHILD )
		syslog( LOG_ERR, "waitpid - %m" );
	    break;
	    }
	}
    return child_count;
    }


static void
check_options( void )
    {
#if defined(TILDE_MAP_1) && defined(TILDE_MAP_2)
    syslog( LOG_CRIT, "both TILDE_MAP_1 and TILDE_MAP_2 are defined" );
    exit( 1 );
#endif /* both */
    }


static void
free_httpd_server( httpd_server* hs )
    {
    if ( hs->cwd != (char*) 0 )
	free( (void*) hs->cwd );
    if ( hs->cgi_pattern != (char*) 0 )
	free( (void*) hs->cgi_pattern );
    free( (void*) hs );
    }


httpd_server*
httpd_initialize(
    char* hostname, u_int addr, int port, char* cgi_pattern, char* cwd,
    FILE* logfp, int chrooted )
    {
    httpd_server* hs;
    int on;
    struct sockaddr_in sa;
    char* cp;

    check_options();

    /* Set up child-process reaper. */
    reap_time = min( MIN_REAP_TIME * 4, MAX_REAP_TIME );
    (void) tmr_create(
	(struct timeval*) 0, child_reaper, (ClientData) 0, reap_time * 1000L,
	0 );

    hs = NEW( httpd_server, 1 );
    if ( hs == (httpd_server*) 0 )
	{
	syslog( LOG_CRIT, "out of memory" );
	return (httpd_server*) 0;
	}
    if ( hostname == (char*) 0 )
	hs->hostname = (char*) 0;
    else
	hs->hostname = strdup( hostname );
    hs->port = port;
    if ( cgi_pattern == (char*) 0 )
	hs->cgi_pattern = (char*) 0;
    else
	{
	/* Nuke any leading slashes. */
	if ( cgi_pattern[0] == '/' )
	    ++cgi_pattern;
	hs->cgi_pattern = strdup( cgi_pattern );
	if ( hs->cgi_pattern == (char*) 0 )
	    {
	    syslog( LOG_CRIT, "out of memory" );
	    return (httpd_server*) 0;
	    }
	/* Nuke any leading slashes in the cgi pattern. */
	while ( ( cp = strstr( hs->cgi_pattern, "|/" ) ) != (char*) 0 )
	    (void) strcpy( cp + 1, cp + 2 );
	}
    hs->cwd = strdup( cwd );
    if ( hs->cwd == (char*) 0 )
	{
	syslog( LOG_CRIT, "out of memory" );
	return (httpd_server*) 0;
	}
    hs->logfp = logfp;
    hs->chrooted = chrooted;

    /* Create socket. */
    hs->listen_fd = socket( AF_INET, SOCK_STREAM, 0 );
    if ( hs->listen_fd < 0 )
	{
	syslog( LOG_CRIT, "socket - %m" );
	free_httpd_server( hs );
	return (httpd_server*) 0;
	}
    (void) fcntl( hs->listen_fd, F_SETFD, 1 );

    /* Allow reuse of local addresses. */
    on = 1;
    if ( setsockopt(
	     hs->listen_fd, SOL_SOCKET, SO_REUSEADDR, (char*) &on,
	     sizeof(on) ) < 0 )
        syslog( LOG_CRIT, "setsockopt SO_REUSEADDR - %m" );

    /* Bind to it. */
    memset( (char*) &sa, 0, sizeof(sa) );
    sa.sin_family = AF_INET;
    sa.sin_addr.s_addr = addr;
    sa.sin_port = htons( hs->port );
    hs->host_addr = sa.sin_addr;
    if ( bind( hs->listen_fd, (struct sockaddr*) &sa, sizeof(sa) ) < 0 )
	{
	syslog( LOG_CRIT, "bind %.80s - %m", inet_ntoa( sa.sin_addr ) );
	(void) close( hs->listen_fd );
	free_httpd_server( hs );
	return (httpd_server*) 0;
	}

    /* Set the listen file descriptor to no-delay mode. */
    if ( fcntl( hs->listen_fd, F_SETFL, O_NDELAY ) < 0 )
	{
	syslog( LOG_CRIT, "fcntl O_NDELAY - %m" );
	(void) close( hs->listen_fd );
	free_httpd_server( hs );
	return (httpd_server*) 0;
	}

    /* Start a listen going. */
    if ( listen( hs->listen_fd, LISTEN_BACKLOG ) < 0 )
	{
	syslog( LOG_CRIT, "listen - %m" );
	(void) close( hs->listen_fd );
	free_httpd_server( hs );
	return (httpd_server*) 0;
	}

    /* Done initializing. */
    if ( hs->hostname == (char*) 0 )
	syslog( LOG_INFO, "%s starting on port %d", SERVER_SOFTWARE, hs->port );
    else
	syslog(
	    LOG_INFO, "%s starting on %.80s, port %d", SERVER_SOFTWARE,
	    inet_ntoa( hs->host_addr ), hs->port );
    return hs;
    }


void
httpd_terminate( httpd_server* hs )
    {
    (void) close( hs->listen_fd );
    if ( hs->logfp != (FILE*) 0 )
	(void) fclose( hs->logfp );
    free_httpd_server( hs );
    }


static char* ok200title = "OK";
static char* ok206title = "Partial Content";

static char* err302title = "Found";
static char* err302form = "The actual URL is '%.80s'.\n";

static char* err304title = "Not Modified";

char* httpd_err400title = "Bad Request";
char* httpd_err400form =
    "Your request has bad syntax or is inherently impossible to satisfy.\n";

#ifdef AUTH_FILE
static char* err401title = "Unauthorized";
static char* err401form =
    "Authorization required for the URL '%.80s'.\n";
#endif /* AUTH_FILE */

static char* err403title = "Forbidden";
static char* err403form =
    "You do not have permission to get URL '%.80s' from this server.\n";

static char* err404title = "Not Found";
static char* err404form =
    "The requested URL '%.80s' was not found on this server.\n";

char* httpd_err408title = "Request Timeout";
char* httpd_err408form =
    "No request appeared within a reasonable time period.\n";

static char* err500title = "Internal Error";
static char* err500form =
    "There was an unusual problem serving the requested URL '%.80s'.\n";

static char* err501title = "Not Implemented";
static char* err501form =
    "The requested method '%.80s' is not implemented by this server.\n";

char* httpd_err503title = "Service Temporarily Overloaded";
char* httpd_err503form =
    "The requested URL '%.80s' is temporarily overloaded.  Please try again later.\n";


/* Append a string to the buffer waiting to be sent as response. */
static void
add_response( httpd_conn* hc, char* str )
    {
    int len;

    len = strlen( str );
    realloc_str( &hc->response, &hc->maxresponse, hc->responselen + len );
    (void) memcpy( &(hc->response[hc->responselen]), str, len );
    hc->responselen += len;
    }

/* Send the buffered response. */
void
httpd_write_response( httpd_conn* hc )
    {
    if ( hc->responselen > 0 )
	{
	(void) write( hc->conn_fd, hc->response, hc->responselen );
	hc->responselen = 0;
	}
    }


static void
send_mime( httpd_conn* hc, int status, char* title, char* encodings, char* extraheads, char* type, int length, time_t mod )
    {
    time_t now;
    char nowbuf[100];
    char modbuf[100];
    char buf[1000];
    int partial_content;

    hc->status = status;
    hc->bytes = length;
    if ( hc->mime_flag )
	{
	if ( status == 200 && hc->got_range &&
	     ( hc->end_byte_loc >= hc->init_byte_loc ) &&
	     ( ( hc->end_byte_loc != length - 1 ) ||
	       ( hc->init_byte_loc != 0 ) ) &&
	     ( hc->range_if == (time_t) -1 ||
	       hc->range_if == hc->sb.st_mtime ) )
	    {
	    partial_content = 1;
	    hc->status = status = 206;
	    title = ok206title;
	    }
	else
	    partial_content = 0;

	now = time( (time_t*) 0 );
	if ( mod == (time_t) 0 )
	    mod = now;
#ifdef EMBED
	modbuf[0] = nowbuf[0] = 0;
#else
	(void) strftime( nowbuf, sizeof(nowbuf), rfc1123fmt, gmtime( &now ) );
	(void) strftime( modbuf, sizeof(modbuf), rfc1123fmt, gmtime( &mod ) );
#endif
	(void) sprintf( buf,
	    "%.20s %d %s\r\nServer: %s\r\nContent-type: %s\r\nDate: %s\r\nLast-modified: %s\r\nAccept-Ranges: bytes\r\nConnection: close\r\n",
	    hc->protocol, status, title, SERVER_SOFTWARE, type, nowbuf,
	    modbuf );
	add_response( hc, buf );
	if ( encodings[0] != '\0' )
	    {
	    (void) sprintf( buf, "Content-encoding: %s\r\n", encodings );
	    add_response( hc, buf );
	    }
	if ( partial_content )
	    {
	    (void) sprintf(
		buf, "Content-range: bytes %ld-%ld/%d\r\nContent-length: %ld\r\n",
		(long) hc->init_byte_loc, (long) hc->end_byte_loc, length,
		(long) ( hc->end_byte_loc - hc->init_byte_loc + 1 ) );
	    add_response( hc, buf );
	    }
	else if ( length >= 0 )
	    {
	    (void) sprintf( buf, "Content-length: %d\r\n", length );
	    add_response( hc, buf );
	    }
	if ( extraheads[0] != '\0' )
	    add_response( hc, extraheads );
	add_response( hc, "\r\n" );
	}
    }


static void
realloc_str( char** strP, int* maxsizeP, int size )
    {
    if ( *maxsizeP == 0 )
	{
	*maxsizeP = MAX( 200, size );	/* arbitrary */
	*strP = NEW( char, *maxsizeP + 1 );
	}
    else if ( size > *maxsizeP )
	{
	*maxsizeP = MAX( *maxsizeP * 2, size * 5 / 4 );
	*strP = RENEW( *strP, char, *maxsizeP + 1 );
	}
    else
	return;
    if ( *strP == (char*) 0 )
	{
	syslog( LOG_ERR, "out of memory" );
	exit( 1 );
	}
    }


static void
send_response( httpd_conn* hc, int status, char* title, char* extrahead, char* form, char* arg )