ref: 5c1feb0ef0b795e5de71e956f9ccddcd5c4b7f21
dir: /sys/src/cmd/upas/fs/plan9.c/
#include "common.h"
#include <ctype.h>
#include <plumb.h>
#include <libsec.h>
#include "dat.h"
enum {
Buffersize = 64*1024,
};
typedef struct Inbuf Inbuf;
struct Inbuf
{
int fd;
uchar *lim;
uchar *rptr;
uchar *wptr;
uchar data[Buffersize+7];
};
static void
addtomessage(Message *m, uchar *p, int n, int done)
{
int i, len;
// add to message (+1 in malloc is for a trailing NUL)
if(m->lim - m->end < n){
if(m->start != nil){
i = m->end-m->start;
if(done)
len = i + n;
else
len = (4*(i+n))/3;
m->start = erealloc(m->start, len + 1);
m->end = m->start + i;
} else {
if(done)
len = n;
else
len = 2*n;
m->start = emalloc(len + 1);
m->end = m->start;
}
m->lim = m->start + len;
*m->lim = '\0';
}
memmove(m->end, p, n);
m->end += n;
*m->end = '\0';
}
//
// read in a single message
//
static int
readmessage(Message *m, Inbuf *inb)
{
int i, n, done;
uchar *p, *np;
char sdigest[SHA1dlen*2+1];
char tmp[64];
for(done = 0; !done;){
n = inb->wptr - inb->rptr;
if(n < 6){
if(n)
memmove(inb->data, inb->rptr, n);
inb->rptr = inb->data;
inb->wptr = inb->rptr + n;
i = read(inb->fd, inb->wptr, Buffersize);
if(i < 0){
if(fd2path(inb->fd, tmp, sizeof tmp) < 0)
strcpy(tmp, "unknown mailbox");
fprint(2, "error reading '%s': %r\n", tmp);
return -1;
}
if(i == 0){
if(n != 0)
addtomessage(m, inb->rptr, n, 1);
if(m->end == m->start)
return -1;
break;
}
inb->wptr += i;
}
// look for end of message
for(p = inb->rptr; p < inb->wptr; p = np+1){
// first part of search for '\nFrom '
np = memchr(p, '\n', inb->wptr - p);
if(np == nil){
p = inb->wptr;
break;
}
/*
* if we've found a \n but there's
* not enough room for '\nFrom ', don't do
* the comparison till we've read in more.
*/
if(inb->wptr - np < 6){
p = np;
break;
}
if(strncmp((char*)np, "\nFrom ", 6) == 0){
done = 1;
p = np+1;
break;
}
}
// add to message (+ 1 in malloc is for a trailing null)
n = p - inb->rptr;
addtomessage(m, inb->rptr, n, done);
inb->rptr += n;
}
// if it doesn't start with a 'From ', this ain't a mailbox
if(strncmp(m->start, "From ", 5) != 0)
return -1;
// dump trailing newline, make sure there's a trailing null
// (helps in body searches)
if(*(m->end-1) == '\n')
m->end--;
*m->end = 0;
m->bend = m->rbend = m->end;
// digest message
sha1((uchar*)m->start, m->end - m->start, m->digest, nil);
for(i = 0; i < SHA1dlen; i++)
sprint(sdigest+2*i, "%2.2ux", m->digest[i]);
m->sdigest = s_copy(sdigest);
return 0;
}
// throw out deleted messages. return number of freshly deleted messages
int
purgedeleted(Mailbox *mb)
{
Message *m, *next;
int newdels;
// forget about what's no longer in the mailbox
newdels = 0;
for(m = mb->root->part; m != nil; m = next){
next = m->next;
if(m->deleted && m->refs == 0){
if(m->inmbox)
newdels++;
delmessage(mb, m);
}
}
return newdels;
}
//
// read in the mailbox and parse into messages.
//
static char*
_readmbox(Mailbox *mb, int doplumb, Mlock *lk)
{
int fd, n;
String *tmp;
Dir *d;
static char err[Errlen];
Message *m, **l;
Inbuf *inb;
char *x;
l = &mb->root->part;
/*
* open the mailbox. If it doesn't exist, try the temporary one.
*/
n = 0;
retry:
fd = open(mb->path, OREAD);
if(fd < 0){
rerrstr(err, sizeof(err));
if(strstr(err, "locked") != nil
|| strstr(err, "exclusive lock") != nil)
if(n++ < 20){
sleep(500); /* wait for lock to go away */
goto retry;
}
if(strstr(err, "exist") != nil){
tmp = s_copy(mb->path);
s_append(tmp, ".tmp");
if(sysrename(s_to_c(tmp), mb->path) == 0){
s_free(tmp);
goto retry;
}
s_free(tmp);
}
return err;
}
/*
* a new qid.path means reread the mailbox, while
* a new qid.vers means read any new messages
*/
d = dirfstat(fd);
if(d == nil){
close(fd);
errstr(err, sizeof(err));
return err;
}
if(mb->d != nil){
if(d->qid.path == mb->d->qid.path && d->qid.vers == mb->d->qid.vers){
close(fd);
free(d);
return nil;
}
if(d->qid.path == mb->d->qid.path){
while(*l != nil)
l = &(*l)->next;
seek(fd, mb->d->length, 0);
}
free(mb->d);
}
mb->d = d;
mb->vers++;
henter(PATH(0, Qtop), mb->name,
(Qid){PATH(mb->id, Qmbox), mb->vers, QTDIR}, nil, mb);
inb = emalloc(sizeof(Inbuf));
inb->rptr = inb->wptr = inb->data;
inb->fd = fd;
// read new messages
snprint(err, sizeof err, "reading '%s'", mb->path);
logmsg(err, nil);
for(;;){
if(lk != nil)
syslockrefresh(lk);
m = newmessage(mb->root);
m->mallocd = 1;
m->inmbox = 1;
if(readmessage(m, inb) < 0){
delmessage(mb, m);
mb->root->subname--;
break;
}
// merge mailbox versions
while(*l != nil){
if(memcmp((*l)->digest, m->digest, SHA1dlen) == 0){
// matches mail we already read, discard
logmsg("duplicate", *l);
delmessage(mb, m);
mb->root->subname--;
m = nil;
l = &(*l)->next;
break;
} else {
// old mail no longer in box, mark deleted
logmsg("disappeared", *l);
if(doplumb)
mailplumb(mb, *l, 1);
(*l)->inmbox = 0;
(*l)->deleted = 1;
l = &(*l)->next;
}
}
if(m == nil)
continue;
x = strchr(m->start, '\n');
if(x == nil)
m->header = m->end;
else
m->header = x + 1;
m->mheader = m->mhend = m->header;
parseunix(m);
parse(m, 0, mb, 0);
logmsg("new", m);
/* chain in */
*l = m;
l = &m->next;
if(doplumb)
mailplumb(mb, m, 0);
}
logmsg("mbox read", nil);
// whatever is left has been removed from the mbox, mark deleted
while(*l != nil){
if(doplumb)
mailplumb(mb, *l, 1);
(*l)->inmbox = 0;
(*l)->deleted = 1;
l = &(*l)->next;
}
close(fd);
free(inb);
return nil;
}
static void
_writembox(Mailbox *mb, Mlock *lk)
{
Dir *d;
Message *m;
String *tmp;
int mode, errs;
Biobuf *b;
tmp = s_copy(mb->path);
s_append(tmp, ".tmp");
/*
* preserve old files permissions, if possible
*/
d = dirstat(mb->path);
if(d != nil){
mode = d->mode&0777;
free(d);
} else
mode = MBOXMODE;
sysremove(s_to_c(tmp));
b = sysopen(s_to_c(tmp), "alc", mode);
if(b == 0){
fprint(2, "can't write temporary mailbox %s: %r\n", s_to_c(tmp));
return;
}
logmsg("writing new mbox", nil);
errs = 0;
for(m = mb->root->part; m != nil; m = m->next){
if(lk != nil)
syslockrefresh(lk);
if(m->deleted)
continue;
logmsg("writing", m);
if(Bwrite(b, m->start, m->end - m->start) < 0)
errs = 1;
if(Bwrite(b, "\n", 1) < 0)
errs = 1;
}
logmsg("wrote new mbox", nil);
if(sysclose(b) < 0)
errs = 1;
if(errs){
fprint(2, "error writing temporary mail file\n");
s_free(tmp);
return;
}
sysremove(mb->path);
if(sysrename(s_to_c(tmp), mb->path) < 0)
fprint(2, "%s: can't rename %s to %s: %r\n", argv0,
s_to_c(tmp), mb->path);
s_free(tmp);
if(mb->d != nil)
free(mb->d);
mb->d = dirstat(mb->path);
}
char*
plan9syncmbox(Mailbox *mb, int doplumb)
{
Mlock *lk;
char *rv;
lk = nil;
if(mb->dolock){
lk = syslock(mb->path);
if(lk == nil)
return "can't lock mailbox";
}
rv = _readmbox(mb, doplumb, lk); /* interpolate */
if(purgedeleted(mb) > 0)
_writembox(mb, lk);
if(lk != nil)
sysunlock(lk);
return rv;
}
//
// look to see if we can open this mail box
//
char*
plan9mbox(Mailbox *mb, char *path)
{
static char err[Errlen];
String *tmp;
if(access(path, AEXIST) < 0){
errstr(err, sizeof(err));
tmp = s_copy(path);
s_append(tmp, ".tmp");
if(access(s_to_c(tmp), AEXIST) < 0){
s_free(tmp);
return err;
}
s_free(tmp);
}
mb->sync = plan9syncmbox;
return nil;
}