/* Unix SMB/Netbios implementation. Version 1.9. Samba utility functions Copyright (C) Andrew Tridgell 1992-1998 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 of the License, 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. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "includes.h" #if (defined(HAVE_NETGROUP) && defined (WITH_AUTOMOUNT)) #ifdef WITH_NISPLUS_HOME #include #else #include "rpcsvc/ypclnt.h" #endif #endif #ifdef WITH_SSL #include #undef Realloc /* SSLeay defines this and samba has a function of this name */ extern SSL *ssl; extern int sslFd; #endif /* WITH_SSL */ pstring scope = ""; struct in_addr ipzero = { 0 }; #if 0 int DEBUGLEVEL = 100; #else int DEBUGLEVEL = 0; #endif int Protocol = PROTOCOL_COREPLUS; /* a default finfo structure to ensure all fields are sensible */ file_info def_finfo = {-1,0,0,0,0,0,0,""}; /* the client file descriptor */ extern int Client; /* this is used by the chaining code */ int chain_size = 0; int trans_num = 0; /* case handling on filenames */ int case_default = CASE_LOWER; /* the following control case operations - they are put here so the client can link easily */ BOOL case_sensitive; BOOL case_preserve; BOOL use_mangled_map = False; BOOL short_case_preserve; BOOL case_mangle; fstring remote_machine=""; fstring local_machine=""; fstring remote_arch="UNKNOWN"; static enum remote_arch_types ra_type = RA_UNKNOWN; fstring remote_proto="UNKNOWN"; pstring myhostname=""; pstring user_socket_options=""; pstring sesssetup_user=""; pstring samlogon_user=""; BOOL sam_logon_in_ssb = False; pstring global_myname = ""; fstring global_myworkgroup = ""; char **my_netbios_names; char *daynames[] = {"Mon","Tue","Wed","Thu","Fri","Sat","Sun"}; char *daynames_short[] = {"M", "Tu", "W", "Th", "F", "Sa", "Su"}; /**************************************************************************** find a suitable temporary directory. The result should be copied immediately as it may be overwritten by a subsequent call ****************************************************************************/ char *tmpdir(void) { char *p; if ((p = getenv("TMPDIR"))) { return p; } return "/tmp"; } /**************************************************************************** determine whether we are in the specified group ****************************************************************************/ BOOL in_group(gid_t group, gid_t current_gid, int ngroups, gid_t *groups) { int i; if (group == current_gid) return(True); for (i=0;i= 0; i--) { if (netbios_name[i] == '.') { netbios_name[i] = 0; break; } } #endif /* TRUNCATE_NETBIOS_NAME */ return netbios_name; } /**************************************************************************** interpret the weird netbios "name". Return the name type ****************************************************************************/ static int name_interpret(char *in,char *out) { int ret; int len = (*in++) / 2; *out=0; if (len > 30 || len<1) return(0); while (len--) { if (in[0] < 'A' || in[0] > 'P' || in[1] < 'A' || in[1] > 'P') { *out = 0; return(0); } *out = ((in[0]-'A')<<4) + (in[1]-'A'); in += 2; out++; } *out = 0; ret = out[-1]; #ifdef NETBIOS_SCOPE /* Handle any scope names */ while(*in) { *out++ = '.'; /* Scope names are separated by periods */ len = *(unsigned char *)in++; StrnCpy(out, in, len); out += len; *out=0; in += len; } #endif return(ret); } /**************************************************************************** mangle a name into netbios format Note: must be (33 + strlen(scope) + 2) bytes long, at minimum. ****************************************************************************/ int name_mangle( char *In, char *Out, char name_type ) { int i; int c; int len; char buf[20]; char *p = Out; /* Safely copy the input string, In, into buf[]. */ (void)memset( buf, 0, 20 ); if (strcmp(In,"*") == 0) buf[0] = '*'; else (void)slprintf( buf, sizeof(buf) - 1, "%-15.15s%c", In, name_type ); /* Place the length of the first field into the output buffer. */ p[0] = 32; p++; /* Now convert the name to the rfc1001/1002 format. */ for( i = 0; i < 16; i++ ) { c = toupper( buf[i] ); p[i*2] = ( (c >> 4) & 0x000F ) + 'A'; p[(i*2)+1] = (c & 0x000F) + 'A'; } p += 32; p[0] = '\0'; /* Add the scope string. */ for( i = 0, len = 0; NULL != scope; i++, len++ ) { switch( scope[i] ) { case '\0': p[0] = len; if( len > 0 ) p[len+1] = 0; return( name_len(Out) ); case '.': p[0] = len; p += (len + 1); len = 0; break; default: p[len+1] = scope[i]; break; } } return( name_len(Out) ); } /* name_mangle */ /******************************************************************* return a string representing an attribute for a file ********************************************************************/ char *attrib_string(uint16 mode) { static fstring attrstr; attrstr[0] = 0; if (mode & aVOLID) fstrcat(attrstr,"V"); if (mode & aDIR) fstrcat(attrstr,"D"); if (mode & aARCH) fstrcat(attrstr,"A"); if (mode & aHIDDEN) fstrcat(attrstr,"H"); if (mode & aSYSTEM) fstrcat(attrstr,"S"); if (mode & aRONLY) fstrcat(attrstr,"R"); return(attrstr); } /**************************************************************************** make a file into unix format ****************************************************************************/ void unix_format(char *fname) { string_replace(fname,'\\','/'); } /**************************************************************************** make a file into dos format ****************************************************************************/ void dos_format(char *fname) { string_replace(fname,'/','\\'); } /******************************************************************* show a smb message structure ********************************************************************/ void show_msg(char *buf) { int i; int bcc=0; if (DEBUGLEVEL < 5) return; DEBUG(5,("size=%d\nsmb_com=0x%x\nsmb_rcls=%d\nsmb_reh=%d\nsmb_err=%d\nsmb_flg=%d\nsmb_flg2=%d\n", smb_len(buf), (int)CVAL(buf,smb_com), (int)CVAL(buf,smb_rcls), (int)CVAL(buf,smb_reh), (int)SVAL(buf,smb_err), (int)CVAL(buf,smb_flg), (int)SVAL(buf,smb_flg2))); DEBUG(5,("smb_tid=%d\nsmb_pid=%d\nsmb_uid=%d\nsmb_mid=%d\nsmt_wct=%d\n", (int)SVAL(buf,smb_tid), (int)SVAL(buf,smb_pid), (int)SVAL(buf,smb_uid), (int)SVAL(buf,smb_mid), (int)CVAL(buf,smb_wct))); for (i=0;i<(int)CVAL(buf,smb_wct);i++) { DEBUG(5,("smb_vwv[%d]=%d (0x%X)\n",i, SVAL(buf,smb_vwv+2*i),SVAL(buf,smb_vwv+2*i))); } bcc = (int)SVAL(buf,smb_vwv+2*(CVAL(buf,smb_wct))); DEBUG(5,("smb_bcc=%d\n",bcc)); if (DEBUGLEVEL < 10) return; if (DEBUGLEVEL < 50) { bcc = MIN(bcc, 512); } dump_data(10, smb_buf(buf), bcc); } /******************************************************************* return the length of an smb packet ********************************************************************/ int smb_len(char *buf) { return( PVAL(buf,3) | (PVAL(buf,2)<<8) | ((PVAL(buf,1)&1)<<16) ); } /******************************************************************* set the length of an smb packet ********************************************************************/ void _smb_setlen(char *buf,int len) { buf[0] = 0; buf[1] = (len&0x10000)>>16; buf[2] = (len&0xFF00)>>8; buf[3] = len&0xFF; } /******************************************************************* set the length and marker of an smb packet ********************************************************************/ void smb_setlen(char *buf,int len) { _smb_setlen(buf,len); CVAL(buf,4) = 0xFF; CVAL(buf,5) = 'S'; CVAL(buf,6) = 'M'; CVAL(buf,7) = 'B'; } /******************************************************************* setup the word count and byte count for a smb message ********************************************************************/ int set_message(char *buf,int num_words,int num_bytes,BOOL zero) { if (zero) bzero(buf + smb_size,num_words*2 + num_bytes); CVAL(buf,smb_wct) = num_words; SSVAL(buf,smb_vwv + num_words*SIZEOFWORD,num_bytes); smb_setlen(buf,smb_size + num_words*2 + num_bytes - 4); return (smb_size + num_words*2 + num_bytes); } /******************************************************************* return the number of smb words ********************************************************************/ static int smb_numwords(char *buf) { return (CVAL(buf,smb_wct)); } /******************************************************************* return the size of the smb_buf region of a message ********************************************************************/ int smb_buflen(char *buf) { return(SVAL(buf,smb_vwv0 + smb_numwords(buf)*2)); } /******************************************************************* return a pointer to the smb_buf data area ********************************************************************/ static int smb_buf_ofs(char *buf) { return (smb_size + CVAL(buf,smb_wct)*2); } /******************************************************************* return a pointer to the smb_buf data area ********************************************************************/ char *smb_buf(char *buf) { return (buf + smb_buf_ofs(buf)); } /******************************************************************* return the SMB offset into an SMB buffer ********************************************************************/ int smb_offset(char *p,char *buf) { return(PTR_DIFF(p,buf+4) + chain_size); } /******************************************************************* close the low 3 fd's and open dev/null in their place ********************************************************************/ void close_low_fds(void) { int fd; int i; close(0); close(1); close(2); /* try and use up these file descriptors, so silly library routines writing to stdout etc won't cause havoc */ for (i=0;i<3;i++) { fd = sys_open("/dev/null",O_RDWR,0); if (fd < 0) fd = sys_open("/dev/null",O_WRONLY,0); if (fd < 0) { DEBUG(0,("Can't open /dev/null\n")); return; } if (fd != i) { DEBUG(0,("Didn't get file descriptor %d\n",i)); return; } } } /**************************************************************************** Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available, else if SYSV use O_NDELAY if BSD use FNDELAY ****************************************************************************/ int set_blocking(int fd, BOOL set) { int val; #ifdef O_NONBLOCK #define FLAG_TO_SET O_NONBLOCK #else #ifdef SYSV #define FLAG_TO_SET O_NDELAY #else /* BSD */ #define FLAG_TO_SET FNDELAY #endif #endif if((val = fcntl(fd, F_GETFL, 0)) == -1) return -1; if(set) /* Turn blocking on - ie. clear nonblock flag */ val &= ~FLAG_TO_SET; else val |= FLAG_TO_SET; return fcntl( fd, F_SETFL, val); #undef FLAG_TO_SET } /**************************************************************************** find a pointer to a netbios name ****************************************************************************/ static char *name_ptr(char *buf,int ofs) { unsigned char c = *(unsigned char *)(buf+ofs); if ((c & 0xC0) == 0xC0) { uint16 l; char p[2]; memcpy(p,buf+ofs,2); p[0] &= ~0xC0; l = RSVAL(p,0); DEBUG(5,("name ptr to pos %d from %d is %s\n",l,ofs,buf+l)); return(buf + l); } else return(buf+ofs); } /**************************************************************************** extract a netbios name from a buf ****************************************************************************/ int name_extract(char *buf,int ofs,char *name) { char *p = name_ptr(buf,ofs); int d = PTR_DIFF(p,buf+ofs); pstrcpy(name,""); if (d < -50 || d > 50) return(0); return(name_interpret(p,name)); } /**************************************************************************** return the total storage length of a mangled name ****************************************************************************/ int name_len(char *s1) { /* NOTE: this argument _must_ be unsigned */ unsigned char *s = (unsigned char *)s1; int len; /* If the two high bits of the byte are set, return 2. */ if (0xC0 == (*s & 0xC0)) return(2); /* Add up the length bytes. */ for (len = 1; (*s); s += (*s) + 1) { len += *s + 1; SMB_ASSERT(len < 80); } return(len); } /* name_len */ /**************************************************************************** become a daemon, discarding the controlling terminal ****************************************************************************/ void become_daemon(void) { if (fork()) { _exit(0); } /* detach from the terminal */ #ifdef HAVE_SETSID setsid(); #elif defined(TIOCNOTTY) { int i = sys_open("/dev/tty", O_RDWR, 0); if (i != -1) { ioctl(i, (int) TIOCNOTTY, (char *)0); close(i); } } #endif /* HAVE_SETSID */ /* Close fd's 0,1,2. Needed if started by rsh */ close_low_fds(); } /**************************************************************************** put up a yes/no prompt ****************************************************************************/ BOOL yesno(char *p) { pstring ans; printf("%s",p); if (!fgets(ans,sizeof(ans)-1,stdin)) return(False); if (*ans == 'y' || *ans == 'Y') return(True); return(False); } #ifdef HPUX /**************************************************************************** this is a version of setbuffer() for those machines that only have setvbuf ****************************************************************************/ void setbuffer(FILE *f,char *buf,int bufsize) { setvbuf(f,buf,_IOFBF,bufsize); } #endif /**************************************************************************** expand a pointer to be a particular size ****************************************************************************/ void *Realloc(void *p,size_t size) { void *ret=NULL; if (size == 0) { if (p) free(p); DEBUG(5,("Realloc asked for 0 bytes\n")); return NULL; } if (!p) ret = (void *)malloc(size); else ret = (void *)realloc(p,size); #ifdef MEM_MAN { extern FILE *dbf; smb_mem_write_info(ret, dbf); } #endif if (!ret) DEBUG(0,("Memory allocation error: failed to expand to %d bytes\n",size)); return(ret); } /**************************************************************************** get my own name and IP ****************************************************************************/ BOOL get_myname(char *my_name,struct in_addr *ip) { struct hostent *hp; pstring hostname; *hostname = 0; /* get my host name */ if (gethostname(hostname, MAXHOSTNAMELEN) == -1) { DEBUG(0,("gethostname failed\n")); return False; } /* get host info */ if ((hp = Get_Hostbyname(hostname)) == 0) { DEBUG(0,( "Get_Hostbyname: Unknown host %s\n",hostname)); return False; } if (my_name) { /* split off any parts after an initial . */ char *p = strchr(hostname,'.'); if (p) *p = 0; fstrcpy(my_name,hostname); } if (ip) putip((char *)ip,(char *)hp->h_addr); return(True); } /**************************************************************************** true if two IP addresses are equal ****************************************************************************/ BOOL ip_equal(struct in_addr ip1,struct in_addr ip2) { uint32 a1,a2; a1 = ntohl(ip1.s_addr); a2 = ntohl(ip2.s_addr); return(a1 == a2); } /**************************************************************************** interpret a protocol description string, with a default ****************************************************************************/ int interpret_protocol(char *str,int def) { if (strequal(str,"NT1")) return(PROTOCOL_NT1); if (strequal(str,"LANMAN2")) return(PROTOCOL_LANMAN2); if (strequal(str,"LANMAN1")) return(PROTOCOL_LANMAN1); if (strequal(str,"CORE")) return(PROTOCOL_CORE); if (strequal(str,"COREPLUS")) return(PROTOCOL_COREPLUS); if (strequal(str,"CORE+")) return(PROTOCOL_COREPLUS); DEBUG(0,("Unrecognised protocol level %s\n",str)); return(def); } /**************************************************************************** interpret an internet address or name into an IP address in 4 byte form ****************************************************************************/ uint32 interpret_addr(char *str) { struct hostent *hp; uint32 res; int i; BOOL pure_address = True; if (strcmp(str,"0.0.0.0") == 0) return(0); if (strcmp(str,"255.255.255.255") == 0) return(0xFFFFFFFF); for (i=0; pure_address && str[i]; i++) if (!(isdigit((int)str[i]) || str[i] == '.')) pure_address = False; /* if it's in the form of an IP address then get the lib to interpret it */ if (pure_address) { res = inet_addr(str); } else { /* otherwise assume it's a network name of some sort and use Get_Hostbyname */ if ((hp = Get_Hostbyname(str)) == 0) { DEBUG(3,("Get_Hostbyname: Unknown host. %s\n",str)); return 0; } if(hp->h_addr == NULL) { DEBUG(3,("Get_Hostbyname: host address is invalid for host %s\n",str)); return 0; } putip((char *)&res,(char *)hp->h_addr); } if (res == (uint32)-1) return(0); return(res); } /******************************************************************* a convenient addition to interpret_addr() ******************************************************************/ struct in_addr *interpret_addr2(char *str) { static struct in_addr ret; uint32 a = interpret_addr(str); ret.s_addr = a; return(&ret); } /******************************************************************* check if an IP is the 0.0.0.0 ******************************************************************/ BOOL zero_ip(struct in_addr ip) { uint32 a; putip((char *)&a,(char *)&ip); return(a == 0); } /******************************************************************* matchname - determine if host name matches IP address ******************************************************************/ BOOL matchname(char *remotehost,struct in_addr addr) { struct hostent *hp; int i; if ((hp = Get_Hostbyname(remotehost)) == 0) { DEBUG(0,("Get_Hostbyname(%s): lookup failure", remotehost)); return False; } /* * Make sure that gethostbyname() returns the "correct" host name. * Unfortunately, gethostbyname("localhost") sometimes yields * "localhost.domain". Since the latter host name comes from the * local DNS, we just have to trust it (all bets are off if the local * DNS is perverted). We always check the address list, though. */ if (strcasecmp(remotehost, hp->h_name) && strcasecmp(remotehost, "localhost")) { DEBUG(0,("host name/name mismatch: %s != %s", remotehost, hp->h_name)); return False; } /* Look up the host address in the address list we just got. */ for (i = 0; hp->h_addr_list[i]; i++) { if (memcmp(hp->h_addr_list[i], (caddr_t) & addr, sizeof(addr)) == 0) return True; } /* * The host name does not map to the original host address. Perhaps * someone has compromised a name server. More likely someone botched * it, but that could be dangerous, too. */ DEBUG(0,("host name/address mismatch: %s != %s", inet_ntoa(addr), hp->h_name)); return False; } /******************************************************************* are two IPs on the same subnet? ********************************************************************/ BOOL same_net(struct in_addr ip1,struct in_addr ip2,struct in_addr mask) { uint32 net1,net2,nmask; nmask = ntohl(mask.s_addr); net1 = ntohl(ip1.s_addr); net2 = ntohl(ip2.s_addr); return((net1 & nmask) == (net2 & nmask)); } /**************************************************************************** a wrapper for gethostbyname() that tries with all lower and all upper case if the initial name fails ****************************************************************************/ struct hostent *Get_Hostbyname(const char *name) { char *name2 = strdup(name); struct hostent *ret; if (!name2) { DEBUG(0,("Memory allocation error in Get_Hostbyname! panic\n")); exit(0); } /* * This next test is redundent and causes some systems (with * broken isalnum() calls) problems. * JRA. */ #if 0 if (!isalnum(*name2)) { free(name2); return(NULL); } #endif /* 0 */ ret = gethostbyname(name2); if (ret != NULL) { free(name2); return(ret); } /* try with all lowercase */ strlower(name2); ret = gethostbyname(name2); if (ret != NULL) { free(name2); return(ret); } /* try with all uppercase */ strupper(name2); ret = gethostbyname(name2); if (ret != NULL) { free(name2); return(ret); } /* nothing works :-( */ free(name2); return(NULL); } /**************************************************************************** check if a process exists. Does this work on all unixes? ****************************************************************************/ BOOL process_exists(int pid) { return(kill(pid,0) == 0 || errno != ESRCH); } /******************************************************************* is the name specified one of my netbios names returns true is it is equal, false otherwise ********************************************************************/ BOOL is_myname(char *s) { int n; BOOL ret = False; for (n=0; my_netbios_names[n]; n++) { if (strequal(my_netbios_names[n], s)) ret=True; } DEBUG(8, ("is_myname(\"%s\") returns %d\n", s, ret)); return(ret); } /******************************************************************* set the horrid remote_arch string based on an enum. ********************************************************************/ void set_remote_arch(enum remote_arch_types type) { ra_type = type; switch( type ) { case RA_WFWG: fstrcpy(remote_arch, "WfWg"); return; case RA_OS2: fstrcpy(remote_arch, "OS2"); return; case RA_WIN95: fstrcpy(remote_arch, "Win95"); return; case RA_WINNT: fstrcpy(remote_arch, "WinNT"); return; case RA_SAMBA: fstrcpy(remote_arch,"Samba"); return; default: ra_type = RA_UNKNOWN; fstrcpy(remote_arch, "UNKNOWN"); break; } } /******************************************************************* Get the remote_arch type. ********************************************************************/ enum remote_arch_types get_remote_arch(void) { return ra_type; } /******************************************************************* align a pointer to a multiple of 4 bytes. ********************************************************************/ char *align4(char *q, char *base) { int mod = PTR_DIFF(q, base) & 3; if (mod != 0) { q += mod; } return q; } /******************************************************************* align a pointer to a multiple of 2 bytes ********************************************************************/ char *align2(char *q, char *base) { if (PTR_DIFF(q, base) & 1) { q++; } return q; } void out_ascii(FILE *f, const unsigned char *buf,int len) { int i; for (i=0;i(per_line/2)) fprintf(f, " "); while (n--) { fprintf(f, " "); } n = MIN(per_line/2,i%per_line); out_ascii(f,&buf[i-(i%per_line)],n); fprintf(f, " "); n = (i%per_line) - n; if (n>0) out_ascii(f,&buf[i-n],n); fprintf(f, "\n"); } } void print_asc(int level, unsigned char const *buf,int len) { int i; for (i=0;i8) DEBUGADD(level,(" ")); while (n--) DEBUGADD(level,(" ")); n = MIN(8,i%16); print_asc(level,&buf[i-(i%16)],n); DEBUGADD(level,(" ")); n = (i%16) - n; if (n>0) print_asc(level,&buf[i-n],n); DEBUGADD(level,("\n")); } } char *tab_depth(int depth) { static pstring spaces; memset(spaces, ' ', depth * 4); spaces[depth * 4] = 0; return spaces; } /***************************************************************************** * Provide a checksum on a string * * Input: s - the null-terminated character string for which the checksum * will be calculated. * * Output: The checksum value calculated for s. * * **************************************************************************** */ int str_checksum(const char *s) { int res = 0; int c; int i=0; while(*s) { c = *s; res ^= (c << (i % 15)) ^ (c >> (15-(i%15))); s++; i++; } return(res); } /* str_checksum */ /***************************************************************** zero a memory area then free it. Used to catch bugs faster *****************************************************************/ void zero_free(void *p, size_t size) { memset(p, 0, size); free(p); } /******************************************************************* a readdir wrapper which just returns the file name ********************************************************************/ char *readdirname(DIR *p) { struct dirent *ptr; char *dname; if (!p) return(NULL); ptr = (struct dirent *)readdir(p); if (!ptr) return(NULL); dname = ptr->d_name; #ifdef NEXT2 if (telldir(p) < 0) return(NULL); #endif #ifdef HAVE_BROKEN_READDIR /* using /usr/ucb/cc is BAD */ dname = dname - 2; #endif { static pstring buf; memcpy(buf, dname, NAMLEN(ptr)+1); dname = buf; } return(dname); } /******************************************************** resolve via "hosts" method *********************************************************/ static BOOL resolve_hosts(const char *name, struct in_addr *return_ip) { /* * "host" means do a localhost, or dns lookup. */ struct hostent *hp; if (((hp = Get_Hostbyname(name)) != NULL) && (hp->h_addr != NULL)) { putip((char *)return_ip,(char *)hp->h_addr); return True; } return False; } /******************************************************** Resolve a name into an IP address. Use this function if the string is either an IP address, DNS or host name or NetBIOS name. This uses the name switch in the smb.conf to determine the order of name resolution. *********************************************************/ BOOL resolve_name(const char *name, struct in_addr *return_ip, int name_type) { int i; BOOL pure_address = True; if (strcmp(name,"0.0.0.0") == 0) { return_ip->s_addr = 0; return True; } if (strcmp(name,"255.255.255.255") == 0) { return_ip->s_addr = 0xFFFFFFFF; return True; } for (i=0; pure_address && name[i]; i++) if (!(isdigit((int)name[i]) || name[i] == '.')) pure_address = False; /* if it's in the form of an IP address then get the lib to interpret it */ if (pure_address) { return_ip->s_addr = inet_addr(name); return True; } if (name_type == 0x20 && resolve_hosts(name, return_ip)) return True; return False; } /******************************************************************* sleep for a specified number of milliseconds ********************************************************************/ void msleep(int t) { int tdiff=0; struct timeval tval,t1,t2; fd_set fds; GetTimeOfDay(&t1); GetTimeOfDay(&t2); while (tdiff < t) { tval.tv_sec = (t-tdiff)/1000; tval.tv_usec = 1000*((t-tdiff)%1000); FD_ZERO(&fds); errno = 0; sys_select(0,&fds,&tval); GetTimeOfDay(&t2); tdiff = TvalDiff(&t1,&t2); } } /******************************************************************* find the difference in milliseconds between two struct timeval values ********************************************************************/ int TvalDiff(struct timeval *tvalold,struct timeval *tvalnew) { return((tvalnew->tv_sec - tvalold->tv_sec)*1000 + ((int)tvalnew->tv_usec - (int)tvalold->tv_usec)/1000); }