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/*
* lckfiles.c set_lock() and release_lock(), for maintaining
* little file.lck style lockfiles. this isn't what
* we would call a standard mechanism. but it's simple.
*
* it's also not completely integrated with the editor --
* for instance, one can probably bypass the locking mechanism
* in various ways. it is intended as an _aid_ to multiple
* edits. _not_ a cure-all. it works well for the people
* at Baan who contributed the code. i make no other claims
* for it.
*
* operation: if the global "usefilelock" is on, then when
* "file" is edited, a "file.lck" is created, containing the
* username of the user doing the editing. when a file is
* edited for which there already exists a .lck file, the buffer
* mode "locked" is set to true and "locker" is set to the name
* of the user that created the .lck. this infomation will
* appear on the status line, as "locked by pgf", and the
* buffer will be marked readonly. the .lck file will be
* deleted at most of the appropriate times.
*
* $Header: /usr2/foxharp/src/pgf/vile/RCS/lckfiles.c,v 1.7 1996/02/26 04:24:35 pgf Exp $
*
*/
#include "estruct.h"
#include "edef.h"
#if OPT_LCKFILES
#if ! HAVE_LONG_FILE_NAMES
you probably do not want this code -- there are no checks on filename
length when adding .lck to the end
#endif
static void
get_lock_owner(char *lockfile, char *who, int n)
{
FILE *fp;
int l;
if ( (fp = fopen(lockfile,FOPEN_READ)) != (FILE *)0 ) {
l = read(fileno(fp),who,(SIZE_T)(n-1));
if ( l < 0 ) {
(void)strcpy(who,"'Can't read .lck'");
} else {
who[l-1] = EOS; /* Strip \n */
}
fclose(fp);
} else {
(void)strcpy(who,"'Can't open .lck'");
}
}
static char *
ourname(void)
{
char *np;
np = getenv("LOGNAME");
if (!np) np = getenv("USER");
if (!np) np = "unknown";
return np;
}
int
set_lock(const char *fname, char *who, int n)
{
char lockfile[NFILEN];
FILE *fp;
sprintf(lockfile,"%s.lck",fname);
if ( ffexists(lockfile)) {
/* Lockfile exists */
get_lock_owner(lockfile,who,n);
mlwrite("[%s]",who);
return FALSE; /* Can't set lock */
} else {
if (( fp = fopen(lockfile,FOPEN_WRITE)) != (FILE *)0 ) {
(void)lsprintf(who,"%s\n",ourname());
write(fileno(fp),who,strlen(who));
fclose(fp);
} else {
(void)strcpy(who,"'Can't write .lck'");
mlwrite("[%s]",who);
return(FALSE); /* Can't set lock */
}
}
return TRUE; /* Lock ok */
}
void release_lock(const char *fname)
{
char lockfile[NFILEN];
char who[100];
if ( fname && *fname ) {
(void)lsprintf(lockfile,"%s.lck",fname);
get_lock_owner(lockfile,who,sizeof(who));
/* is it ours? */
if (strcmp(who, ourname()) == 0)
unlink(lockfile);
}
}
#endif
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.