mbox.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

	}
}

static void
cencoding(Message *m, Header *h, char *p)
{
	p += h->len;
	p = skipwhite(p);
	if(cistrncmp(p, "base64", 6) == 0)
		m->encoding = Ebase64;
	else if(cistrncmp(p, "quoted-printable", 16) == 0)
		m->encoding = Equoted;
}

static void
cdisposition(Message *m, Header *h, char *p)
{
	p += h->len;
	p = skipwhite(p);
	while(*p){
		if(cistrncmp(p, "inline", 6) == 0){
			m->disposition = Dinline;
		} else if(cistrncmp(p, "attachment", 10) == 0){
			m->disposition = Dfile;
		} else if(cistrncmp(p, "filename=", 9) == 0){
			p += 9;
			setfilename(m, p);
		}
		p = skiptosemi(p);
	}

}

ulong msgallocd, msgfreed;

Message*
newmessage(Message *parent)
{
	static int id;
	Message *m;

	msgallocd++;

	m = emalloc(sizeof(*m));
	memset(m, 0, sizeof(*m));
	m->disposition = Dnone;
	m->type = s_copy("text/plain");
	m->charset = s_copy("iso-8859-1");
	m->id = newid();
	if(parent)
		sprint(m->name, "%d", ++(parent->subname));
	if(parent == nil)
		parent = m;
	m->whole = parent;
	m->hlen = -1;
	return m;
}

// delete a message from a mailbox
void
delmessage(Mailbox *mb, Message *m)
{
	Message **l;
	int i;

	mb->vers++;
	msgfreed++;

	if(m->whole != m){
		// unchain from parent
		for(l = &m->whole->part; *l && *l != m; l = &(*l)->next)
			;
		if(*l != nil)
			*l = m->next;

		// clear out of name lookup hash table
		if(m->whole->whole == m->whole)
			hfree(PATH(mb->id, Qmbox), m->name);
		else
			hfree(PATH(m->whole->id, Qdir), m->name);
		for(i = 0; i < Qmax; i++)
			hfree(PATH(m->id, Qdir), dirtab[i]);
	}

	/* recurse through sub-parts */
	while(m->part)
		delmessage(mb, m->part);

	/* free memory */
	if(m->mallocd)
		free(m->start);
	if(m->hallocd)
		free(m->header);
	if(m->ballocd)
		free(m->body);
	s_free(m->unixfrom);
	s_free(m->unixdate);
	s_free(m->unixheader);
	s_free(m->from822);
	s_free(m->sender822);
	s_free(m->to822);
	s_free(m->bcc822);
	s_free(m->cc822);
	s_free(m->replyto822);
	s_free(m->date822);
	s_free(m->inreplyto822);
	s_free(m->subject822);
	s_free(m->messageid822);
	s_free(m->addrs);
	s_free(m->mimeversion);
	s_free(m->sdigest);
	s_free(m->boundary);
	s_free(m->type);
	s_free(m->charset);
	s_free(m->filename);

	free(m);
}

// mark messages (identified by path) for deletion
void
delmessages(int ac, char **av)
{
	Mailbox *mb;
	Message *m;
	int i, needwrite;

	qlock(&mbllock);
	for(mb = mbl; mb != nil; mb = mb->next)
		if(strcmp(av[0], mb->name) == 0){
			qlock(mb);
			break;
		}
	qunlock(&mbllock);
	if(mb == nil)
		return;

	needwrite = 0;
	for(i = 1; i < ac; i++){
		for(m = mb->root->part; m != nil; m = m->next)
			if(strcmp(m->name, av[i]) == 0){
				if(!m->deleted){
					mailplumb(mb, m, 1);
					needwrite = 1;
					m->deleted = 1;
					logmsg("deleting", m);
				}
				break;
			}
	}
	if(needwrite)
		syncmbox(mb, 1);
	qunlock(mb);
}

/*
 *  the following are called with the mailbox qlocked
 */
void
msgincref(Message *m)
{
	m->refs++;
}
void
msgdecref(Mailbox *mb, Message *m)
{
	m->refs--;
	if(m->refs == 0 && m->deleted)
		syncmbox(mb, 1);
}

/*
 *  the following are called with mbllock'd
 */
void
mboxincref(Mailbox *mb)
{
	assert(mb->refs > 0);
	mb->refs++;
}
void
mboxdecref(Mailbox *mb)
{
	assert(mb->refs > 0);
	qlock(mb);
	mb->refs--;
	if(mb->refs == 0){
		delmessage(mb, mb->root);
		if(mb->ctl)
			hfree(PATH(mb->id, Qmbox), "ctl");
		if(mb->close)
			(*mb->close)(mb);
		free(mb);
	} else
		qunlock(mb);
}

int
cistrncmp(char *a, char *b, int n)
{
	while(n-- > 0){
		if(tolower(*a++) != tolower(*b++))
			return -1;
	}
	return 0;
}

int
cistrcmp(char *a, char *b)
{
	for(;;){
		if(tolower(*a) != tolower(*b++))
			return -1;
		if(*a++ == 0)
			break;
	}
	return 0;
}

static char*
skipwhite(char *p)
{
	while(isspace(*p))
		p++;
	return p;
}

static char*
skiptosemi(char *p)
{
	while(*p && *p != ';')
		p++;
	while(*p == ';' || isspace(*p))
		p++;
	return p;
}

static char*
getstring(char *p, String *s, int dolower)
{
	s = s_reset(s);
	p = skipwhite(p);
	if(*p == '"'){
		p++;
		for(;*p && *p != '"'; p++)
			if(dolower)
				s_putc(s, tolower(*p));
			else
				s_putc(s, *p);
		if(*p == '"')
			p++;
		s_terminate(s);

		return p;
	}

	for(; *p && !isspace(*p) && *p != ';'; p++)
		if(dolower)
			s_putc(s, tolower(*p));
		else
			s_putc(s, *p);
	s_terminate(s);

	return p;
}

static void
setfilename(Message *m, char *p)
{
	m->filename = s_reset(m->filename);
	getstring(p, m->filename, 0);
	for(p = s_to_c(m->filename); *p; p++)
		if(*p == ' ' || *p == '\t' || *p == ';')
			*p = '_';
}

//
// undecode message body
//
void
decode(Message *m)
{
	int i, len;
	char *x;

	if(m->decoded)
		return;
	switch(m->encoding){
	case Ebase64:
		len = m->bend - m->body;
		i = (len*3)/4+1;	// room for max chars + null
		x = emalloc(i);
		len = dec64((uchar*)x, i, m->body, len);
		if(m->ballocd)
			free(m->body);
		m->body = x;
		m->bend = x + len;
		m->ballocd = 1;
		break;
	case Equoted:
		len = m->bend - m->body;
		x = emalloc(len+2);	// room for null and possible extra nl
		len = decquoted(x, m->body, m->bend, 0);
		if(m->ballocd)
			free(m->body);
		m->body = x;
		m->bend = x + len;
		m->ballocd = 1;
		break;
	default:
		break;
	}
	m->decoded = 1;
}

// convert latin1 to utf
void
convert(Message *m)
{
	int len;
	char *x;

	// don't convert if we're not a leaf, not text, or already converted
	if(m->converted)
		return;
	if(m->part != nil)
		return;
	if(cistrncmp(s_to_c(m->type), "text", 4) != 0)
		return;

	len = xtoutf(s_to_c(m->charset), &x, m->body, m->bend);
	if(len > 0){
		if(m->ballocd)
			free(m->body);
		m->body = x;
		m->bend = x + len;
		m->ballocd = 1;
	}
	m->converted = 1;
}

static int
hex2int(int x)
{
	if(x >= '0' && x <= '9')
		return x - '0';
	if(x >= 'A' && x <= 'F')
		return (x - 'A') + 10;
	if(x >= 'a' && x <= 'f')
		return (x - 'a') + 10;
	return 0;
}

// underscores are translated in 2047 headers (uscores=1) 
// but not in the body (uscores=0)
static char*
decquotedline(char *out, char *in, char *e, int uscores)
{
	int c, soft;

	/* dump trailing white space */
	while(e >= in && (*e == ' ' || *e == '\t' || *e == '\r' || *e == '\n'))
		e--;

	/* trailing '=' means no newline */
	if(*e == '='){
		soft = 1;
		e--;
	} else
		soft = 0;

	while(in <= e){
		c = (*in++) & 0xff;
		switch(c){
		case '_':
			if(uscores){
				*out++ = ' ';
				break;
			}
		default:
			*out++ = c;
			break;
		case '=':
			c = hex2int(*in++)<<4;
			c |= hex2int(*in++);
			*out++ = c;
			break;
		}
	}
	if(!soft)
		*out++ = '\n';
	*out = 0;

	return out;
}

int
decquoted(char *out, char *in, char *e, int uscores)
{
	char *p, *nl;

	p = out;
	while((nl = strchr(in, '\n')) != nil && nl < e){
		p = decquotedline(p, in, nl, uscores);
		in = nl + 1;
	}
	if(in < e)
		p = decquotedline(p, in, e-1, uscores);

	// make sure we end with a new line
	if(*(p-1) != '\n'){
		*p++ = '\n';
		*p = 0;
	}

	return p - out;
}

static char*
lowercase(char *p)
{
	char *op;
	int c;

	for(op = p; c = *p; p++)
		if(isupper(c))
			*p = tolower(c);
	return op;
}

// translate latin1 directly since it fits neatly in utf
static int
latin1toutf(char **out, char *in, char *e)
{
	int n;
	char *p;
	Rune r;

	n = 0;
	for(p = in; p < e; p++)
		if(*p & 0x80)
			n++;
	if(n == 0)
		return 0;

	n += e-in;
	*out = p = malloc(n+1);
	if(p == nil)
		return 0;

	for(; in < e; in++){
		r = (uchar)*in;
		p += runetochar(p, &r);
	}
	*p = 0;
	return p - *out;
}

// translate any thing using the tcs program
int
xtoutf(char *charset, char **out, char *in, char *e)
{
	char *av[4];
	int totcs[2];
	int fromtcs[2];
	int n, len, sofar;
	char *p;

	// might not need to convert
	if(cistrcmp(charset, "us-ascii") == 0 || cistrcmp(charset, "utf-8") == 0)
		return 0;
	if(cistrcmp(charset, "iso-8859-1") == 0)
		return latin1toutf(out, in, e);

	len = e-in+1;
	sofar = 0;
	*out = p = malloc(len+1);
	if(p == nil)
		return 0;

	av[0] = charset;
	av[1] = "-f";
	av[2] = charset;
	av[3] = 0;
	if(pipe(totcs) < 0)
		goto error;
	if(pipe(fromtcs) < 0){
		close(totcs[0]); close(totcs[1]);
		goto error;
	}
	switch(rfork(RFPROC|RFFDG|RFNOWAIT)){
	case -1:
		close(fromtcs[0]); close(fromtcs[1]);
		close(totcs[0]); close(totcs[1]);
		goto error;
	case 0:
		close(fromtcs[0]); close(totcs[1]);
		dup(fromtcs[1], 1);
		dup(totcs[0], 0);
		close(fromtcs[1]); close(totcs[0]);
		dup(open("/dev/null", OWRITE), 2);
		exec("/bin/tcs", av);
		_exits(0);
	default:
		close(fromtcs[1]); close(totcs[0]);
		switch(rfork(RFPROC|RFFDG|RFNOWAIT)){
		case -1:
			close(fromtcs[0]); close(totcs[1]);
			goto error;
		case 0:
			close(fromtcs[0]);
			while(in < e){
				n = write(totcs[1], in, e-in);
				if(n <= 0)
					break;
				in += n;
			}
			close(totcs[1]);
			_exits(0);
		default:
			close(totcs[1]);
			for(;;){
				n = read(fromtcs[0], &p[sofar], len-sofar);
				if(n <= 0)
					break;
				sofar += n;
				p[sofar] = 0;
				if(sofar == len){
					len += 1024;
					p = realloc(p, len+1);
					if(p == nil)
						goto error;
					*out = p;
				}
			}
			close(fromtcs[0]);
			break;
		}
		break;
	}
	if(sofar == 0)
		goto error;
	return sofar;

error:
	free(*out);
	*out = nil;
	return 0;
}

void *
emalloc(ulong n)
{
	void *p;

	p = mallocz(n, 1);
	if(!p){
		fprint(2, "%s: out of memory alloc %lud\n", argv0, n);
		exits("out of memory");
	}
	setmalloctag(p, getcallerpc(&n));
	return p;
}

void *
erealloc(void *p, ulong n)
{
	if(n == 0)
		n = 1;
	p = realloc(p, n);
	if(!p){
		fprint(2, "%s: out of memory realloc %lud\n", argv0, n);
		exits("out of memory");
	}
	setrealloctag(p, getcallerpc(&p));
	return p;
}

void
mailplumb(Mailbox *mb, Message *m, int delete)
{
	Plumbmsg p;
	Plumbattr a[7];
	char buf[256];
	int ai;
	char lenstr[10], *from, *subject, *date;
	static int fd = -1;

	if(m->subject822 == nil)
		subject = "";
	else
		subject = s_to_c(m->subject822);

	if(m->from822 != nil)
		from = s_to_c(m->from822);
	else if(m->unixfrom != nil)
		from = s_to_c(m->unixfrom);
	else
		from = "";

	if(m->unixdate != nil)
		date = s_to_c(m->unixdate);
	else
		date = "";

	sprint(lenstr, "%ld", m->end-m->start);

	if(biffing && !delete)
		print("[ %s / %s / %s ]\n", from, subject, lenstr);

	if(!plumbing)
		return;

	if(fd < 0)
		fd = plumbopen("send", OWRITE);
	if(fd < 0)
		return;

	p.src = "mailfs";
	p.dst = "seemail";
	p.wdir = "/mail/fs";
	p.type = "text";

	ai = 0;
	a[ai].name = "filetype";
	a[ai].value = "mail";

	a[++ai].name = "sender";
	a[ai].value = from;
	a[ai-1].next = &a[ai];

	a[++ai].name = "length";
	a[ai].value = lenstr;
	a[ai-1].next = &a[ai];

	a[++ai].name = "mailtype";
	a[ai].value = delete?"delete":"new";
	a[ai-1].next = &a[ai];

	a[++ai].name = "date";
	a[ai].value = date;
	a[ai-1].next = &a[ai];

	if(m->sdigest){
		a[++ai].name = "digest";
		a[ai].value = s_to_c(m->sdigest);
		a[ai-1].next = &a[ai];
	}

	a[ai].next = nil;

	p.attr = a;
	snprint(buf, sizeof(buf), "%s/%s/%s",
		mntpt, mb->name, m->name);
	p.ndata = strlen(buf);
	p.data = buf;

	plumbsend(fd, &p);
}

//
// count the number of lines in the body (for imap4)
//
void
countlines(Message *m)
{
	int i;
	char *p;

	i = 0;
	for(p = strchr(m->rbody, '\n'); p != nil && p < m->rbend; p = strchr(p+1, '\n'))
		i++;
	sprint(m->lines, "%d", i);
}

char *LOG = "fs";

void
logmsg(char *s, Message *m)
{
	int pid;

	if(!logging)
		return;
	pid = getpid();
	if(m == nil)
		syslog(0, LOG, "%s.%d: %s", user, pid, s);
	else
		syslog(0, LOG, "%s.%d: %s msg from %s digest %s",
			user, pid, s,
			m->from822 ? s_to_c(m->from822) : "?",
			s_to_c(m->sdigest));
}

/*
 *  squeeze nulls out of the body
 */
static void
nullsqueeze(Message *m)
{
	char *p, *q;

	q = memchr(m->body, 0, m->end-m->body);
	if(q == nil)
		return;

	for(p = m->body; q < m->end; q++){
		if(*q == 0)
			continue;
		*p++ = *q;
	}
	m->bend = m->rbend = m->end = p;
}


//
// convert an RFC822 date into a Unix style date
// for when the Unix From line isn't there (e.g. POP3).
// enough client programs depend on having a Unix date
// that it's easiest to write this conversion code once, right here.
//
// people don't follow RFC822 particularly closely,
// so we use strtotm, which is a bunch of heuristics.
//

extern int strtotm(char*, Tm*);
String*
date822tounix(char *s)
{
	char *p, *q;
	Tm tm;

	if(strtotm(s, &tm) < 0)
		return nil;

	p = asctime(&tm);
	if(q = strchr(p, '\n'))
		*q = '\0';
	return s_copy(p);
}