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ape: reimplement rename() - fixing compiler warnings and handling more error cases

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handle empty filename, dot and dotdot. handle mismatching from/to directory/file
type. cleanup destination file on error. error when attempting to copy non-empty
directories.

little test program:

#include <unistd.h>
#include <stdio.h>

int
main(int argc, char *argv[])
{
	if(argc != 3){
		fprintf(stderr, "usage: %s old new\n", argv[0]);
		return 1;
	}
	if(rename(argv[1], argv[2])){
		perror("rename");
		return 1;
	}
	return 0;
}
This commit is contained in:
cinap_lenrek 2019-06-24 20:09:04 +02:00
parent 4cffc04364
commit 6118d77858
1 changed files with 74 additions and 48 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

122
sys/src/ape/lib/ap/plan9/rename.c
View file

@ -10,66 +10,92 @@
int
rename(const char *from, const char *to)
{
int n, i;
char *f, *t;
Dir *d, nd;
char buf[8192], *f, *t;
Dir *s, *d, nd;
int n, ffd, tfd;
if(access(to, 0) >= 0){
if(_REMOVE(to) < 0){
_syserrno();
return -1;
}
}
if((d = _dirstat(to)) != nil){
free(d);
errno = EEXIST;
f = strrchr(from, '/');
t = strrchr(to, '/');
f = f != nil ? f+1 : (char*)from;
t = t != nil ? t+1 : (char*)to;
if(*f == '\0' || strcmp(f, ".") == 0 || strcmp(f, "..") == 0
|| *t == '\0' || strcmp(t, ".") == 0 || strcmp(t, "..") == 0){
errno = EINVAL;
return -1;
}
if((d = _dirstat(from)) == nil){
if((s = _dirstat(from)) == nil){
_syserrno();
return -1;
}
f = strrchr(from, '/');
t = strrchr(to, '/');
f = f? f+1 : from;
t = t? t+1 : to;
n = 0;
if((d = _dirstat(to)) != nil){
if(d->qid.type == s->qid.type
&& d->qid.path == s->qid.path
&& d->qid.vers == s->qid.vers
&& d->type == s->type
&& d->dev == s->dev)
goto out; /* same file */
if((d->mode ^ s->mode) & DMDIR){
errno = (d->mode & DMDIR) ? EISDIR : ENOTDIR;
goto err;
}
}
/* from and to are in same directory (we miss some cases) */
if(f-from==t-to && strncmp(from, to, f-from)==0){
/* from and to are in same directory (we miss some cases) */
i = strlen(t);
if(d != nil && _REMOVE(to) < 0){
_syserrno();
goto err;
}
_nulldir(&nd);
nd.name = t;
if(_dirwstat(from, &nd) < 0){
_syserrno();
n = -1;
}
}else{
/* different directories: have to copy */
int ffd, tfd;
char buf[8192];
if((ffd = _OPEN(from, OREAD)) < 0 ||
(tfd = _CREATE(to, OWRITE, d->mode)) < 0){
_CLOSE(ffd);
_syserrno();
n = -1;
}
while(n>=0 && (n = _READ(ffd, buf, sizeof(buf))) > 0)
if(_WRITE(tfd, buf, n) != n){
_syserrno();
n = -1;
}
_CLOSE(ffd);
_CLOSE(tfd);
if(n>0)
n = 0;
if(n == 0) {
if(_REMOVE(from) < 0){
_syserrno();
return -1;
}
goto err;
}
goto out;
}
/* different directories: have to copy */
if((ffd = _OPEN(from, OREAD)) < 0){
_syserrno();
goto err;
}
if((s->mode & DMDIR) != 0 && _READ(ffd, buf, sizeof(buf)) > 0){
/* cannot copy non-empty directories */
errno = EXDEV;
_CLOSE(ffd);
goto err;
}
if(d != nil && _REMOVE(to) < 0){
_syserrno();
_CLOSE(ffd);
goto err;
}
if((tfd = _CREATE(to, OWRITE, s->mode)) < 0){
_syserrno();
_CLOSE(ffd);
goto err;
}
while((n = _READ(ffd, buf, sizeof(buf))) > 0){
if(_WRITE(tfd, buf, n) != n)
break;
}
_CLOSE(ffd);
_CLOSE(tfd);
if(n != 0 || _REMOVE(from) < 0){
_syserrno();
_REMOVE(to); /* cleanup */
goto err;
}
out:
free(s);
free(d);
return n;
return 0;
err:
free(s);
free(d);
return -1;
}