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libdisk: error handling, sanity checks

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- make sure disk file is an actual file and not a directory, log or empty file
- sanity check: file has to be at least one sector to be a disk
- simplify error handling using freedisk()
This commit is contained in:
cinap_lenrek 2015-05-31 12:58:13 +02:00
parent ce76af64fe
commit 3e124e1f13
1 changed files with 34 additions and 18 deletions
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52
sys/src/libdisk/disk.c
View file

@ -208,15 +208,26 @@ findgeometry(Disk *disk)
}
}
static Disk*
freedisk(Disk *d)
{
if(d->fd >= 0)
close(d->fd);
if(d->wfd >= 0)
close(d->wfd);
if(d->ctlfd >= 0)
close(d->ctlfd);
free(d);
return nil;
}
static Disk*
openfile(Disk *disk)
{
Dir *d;
if((d = dirfstat(disk->fd)) == nil){
free(disk);
return nil;
}
if((d = dirfstat(disk->fd)) == nil)
return freedisk(disk);
disk->secsize = 512;
disk->size = d->length;
@ -224,6 +235,11 @@ openfile(Disk *disk)
disk->offset = 0;
free(d);
if(disk->secs == 0){
werrstr("file too small to be a disk");
return freedisk(disk);
}
findgeometry(disk);
return mkwidth(disk);
}
@ -274,6 +290,7 @@ opendisk(char *disk, int rdonly, int noctl)
{
char *p, *q;
Disk *d;
Dir *s;
d = mallocz(sizeof(*d), 1);
if(d == nil)
@ -284,10 +301,17 @@ opendisk(char *disk, int rdonly, int noctl)
d->fd = open(disk, OREAD);
if(d->fd < 0) {
werrstr("cannot open disk file");
free(d);
return nil;
werrstr("cannot open disk file: %r");
return freedisk(d);
}
if((s = dirfstat(d->fd)) == nil)
return freedisk(d);
if((s->mode & (DMDIR|DMAPPEND)) != 0){
free(s);
werrstr("not a disk file: %s", disk);
return freedisk(d);
}
free(s);
if(rdonly == 0) {
d->wfd = open(disk, OWRITE);
@ -299,12 +323,8 @@ opendisk(char *disk, int rdonly, int noctl)
return openfile(d);
p = malloc(strlen(disk) + 4); /* 4: slop for "ctl\0" */
if(p == nil) {
close(d->wfd);
close(d->fd);
free(d);
return nil;
}
if(p == nil)
return freedisk(d);
strcpy(p, disk);
/* check for floppy(3) disk */
@ -334,12 +354,8 @@ opendisk(char *disk, int rdonly, int noctl)
d->type = Tsd;
d->part = strdup(disk+(q-p));
if(d->part == nil){
close(d->ctlfd);
close(d->wfd);
close(d->fd);
free(p);
free(d);
return nil;
return freedisk(d);
}
return opensd(d);
}