nedmail.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

#include "common.h"
#include <ctype.h>
#include <plumb.h>

typedef struct Message Message;
typedef struct Ctype Ctype;
typedef struct Cmd Cmd;

char	root[Pathlen];
char	mbname[Elemlen];
int	rootlen;
int	didopen;
char	*user;
char	wd[2048];
String	*mbpath;
int	natural;
int	doflush;

int interrupted;

struct Message {
	Message	*next;
	Message	*prev;
	Message	*cmd;
	Message	*child;
	Message	*parent;
	String	*path;
	int	id;
	int	len;
	int	fileno;	// number of directory
	String	*info;
	char	*from;
	char	*to;
	char	*cc;
	char	*replyto;
	char	*date;
	char	*subject;
	char	*type;
	char	*disposition;
	char	*filename;
	char	deleted;
	char	stored;
};

Message top;

struct Ctype {
	char	*type;
	char 	*ext;
	int	display;
	char	*plumbdest;
	Ctype	*next;
};

Ctype ctype[] = {
	{ "text/plain",			"txt",	1,	0	},
	{ "text/html",			"htm",	1,	0	},
	{ "text/html",			"html",	1,	0	},
	{ "text/tab-separated-values",	"tsv",	1,	0	},
	{ "text/richtext",		"rtx",	1,	0	},
	{ "text/rtf",			"rtf",	1,	0	},
	{ "text",			"txt",	1,	0	},
	{ "message/rfc822",		"msg",	0,	0	},
	{ "image/bmp",			"bmp",	0,	"image"	},
	{ "image/jpeg",			"jpg",	0,	"image"	},
	{ "image/gif",			"gif",	0,	"image"	},
	{ "image/png",			"png",	0,	"image"	},
	{ "application/pdf",		"pdf",	0,	"postscript"	},
	{ "application/postscript",	"ps",	0,	"postscript"	},
	{ "application/",		0,	0,	0	},
	{ "image/",			0,	0,	0	},
	{ "multipart/",			"mul",	0,	0	},

};

Message*	acmd(Cmd*, Message*);
Message*	bcmd(Cmd*, Message*);
Message*	dcmd(Cmd*, Message*);
Message*	eqcmd(Cmd*, Message*);
Message*	hcmd(Cmd*, Message*);
Message*	Hcmd(Cmd*, Message*);
Message*	helpcmd(Cmd*, Message*);
Message*	icmd(Cmd*, Message*);
Message*	pcmd(Cmd*, Message*);
Message*	qcmd(Cmd*, Message*);
Message*	rcmd(Cmd*, Message*);
Message*	scmd(Cmd*, Message*);
Message*	ucmd(Cmd*, Message*);
Message*	wcmd(Cmd*, Message*);
Message*	xcmd(Cmd*, Message*);
Message*	ycmd(Cmd*, Message*);
Message*	pipecmd(Cmd*, Message*);
Message*	rpipecmd(Cmd*, Message*);
Message*	bangcmd(Cmd*, Message*);
Message*	Pcmd(Cmd*, Message*);
Message*	mcmd(Cmd*, Message*);
Message*	fcmd(Cmd*, Message*);
Message*	quotecmd(Cmd*, Message*);

struct {
	char		*cmd;
	int		args;
	Message*	(*f)(Cmd*, Message*);
	char		*help;
} cmdtab[] = {
	{ "a",	1,	acmd,	"a        reply to sender and recipients" },
	{ "A",	1,	acmd,	"A        reply to sender and recipients with copy" },
	{ "b",	0,	bcmd,	"b        print the next 10 headers" },
	{ "d",	0,	dcmd,	"d        mark for deletion" },
	{ "f",	0,	fcmd,	"f        file message by from address" },
	{ "h",	0,	hcmd,	"h        print elided message summary (,h for all)" },
	{ "help", 0,	helpcmd, "help     print this info" },
	{ "H",	0,	Hcmd,	"H        print message's MIME structure " },
	{ "i",	0,	icmd,	"i        incorporate new mail" },
	{ "m",	1,	mcmd,	"m addr   forward mail" },
	{ "M",	1,	mcmd,	"M addr   forward mail with message" },
	{ "p",	0,	pcmd,	"p        print the processed message" },
	{ "P",	0,	Pcmd,	"P        print the raw message" },
	{ "\"",	0,	quotecmd, "\"        print a quoted version of msg" },
	{ "q",	0,	qcmd,	"q        exit and remove all deleted mail" },
	{ "r",	1,	rcmd,	"r [addr] reply to sender plus any addrs specified" },
	{ "rf",	1,	rcmd,	"rf [addr]file message and reply" },
	{ "R",	1,	rcmd,	"R [addr] reply including copy of message" },
	{ "Rf",	1,	rcmd,	"Rf [addr]file message and reply with copy" },
	{ "s",	1,	scmd,	"s file   append raw message to file" },
	{ "u",	0,	ucmd,	"u        remove deletion mark" },
	{ "w",	1,	wcmd,	"w file   store message contents as file" },
	{ "x",	0,	xcmd,	"x        exit without flushing deleted messages" },
	{ "y",	0,	ycmd,	"y        synchronize with mail box" },
	{ "=",	1,	eqcmd,	"=        print current message number" },
	{ "|",	1,	pipecmd, "|cmd     pipe message body to a command" },
	{ "||",	1,	rpipecmd, "||cmd     pipe raw message to a command" },
	{ "!",	1,	bangcmd, "!cmd     run a command" },
	{ nil,	0,	nil, 	nil },
};

enum
{
	NARG=	32,
};

struct Cmd {
	Message	*msgs;
	Message	*(*f)(Cmd*, Message*);
	int	an;
	char	*av[NARG];
	int	delete;
};

Biobuf out;
int startedfs;
int reverse;
int longestfrom = 12;

String*		file2string(String*, char*);
int		dir2message(Message*, int);
int		filelen(String*, char*);
String*		extendpath(String*, char*);
void		snprintheader(char*, int, Message*);
void		cracktime(char*, char*, int);
int		cistrncmp(char*, char*, int);
int		cistrcmp(char*, char*);
Reprog*		parsesearch(char**);
char*		parseaddr(char**, Message*, Message*, Message*, Message**);
char*		parsecmd(char*, Cmd*, Message*, Message*);
char*		readline(char*, char*, int);
void		messagecount(Message*);
void		system(char*, char**, int);
void		mkid(String*, Message*);
int		switchmb(char*, char*);
void		closemb(void);
int		lineize(char*, char**, int);
int		rawsearch(Message*, Reprog*);
Message*	dosingleton(Message*, char*);
String*		rooted(String*);
int		plumb(Message*, Ctype*);
String*		addrecolon(char*);
void		exitfs(char*);
Message*	flushdeleted(Message*);

void
usage(void)
{
	fprint(2, "usage: %s [-nr] [-f mailfile] [-s mailfile]\n", argv0);
	fprint(2, "       %s -c dir\n", argv0);
	exits("usage");
}

void
catchnote(void*, char *note)
{
	if(strstr(note, "interrupt") != nil){
		interrupted = 1;
		noted(NCONT);
	}
	noted(NDFLT);
}

char *
plural(int n)
{
	if (n == 1)
		return "";

	return "s";		
}

void
main(int argc, char **argv)
{
	Message *cur, *m, *x;
	char cmdline[4*1024];
	Cmd cmd;
	Ctype *cp;
	char *err;
	int n, cflag;
	char *av[4];
	String *prompt;
	char *file, *singleton;

	Binit(&out, 1, OWRITE);

	file = nil;
	singleton = nil;
	reverse = 1;
	cflag = 0;
	ARGBEGIN {
	case 'c':
		cflag = 1;
		break;
	case 'f':
		file = EARGF(usage());
		break;
	case 's':
		singleton = EARGF(usage());
		break;
	case 'r':
		reverse = 0;
		break;
	case 'n':
		natural = 1;
		reverse = 0;
		break;
	default:
		usage();
		break;
	} ARGEND;

	user = getlog();
	if(user == nil || *user == 0)
		sysfatal("can't read user name");

	if(cflag){
		if(argc > 0)
			creatembox(user, argv[0]);
		else
			creatembox(user, nil);
		exits(0);
	}

	if(argc)
		usage();

	if(access("/mail/fs/ctl", 0) < 0){
		startedfs = 1;
		av[0] = "fs";
		av[1] = "-p";
		av[2] = 0;
		system("/bin/upas/fs", av, -1);
	}

	switchmb(file, singleton);

	top.path = s_copy(root);

	for(cp = ctype; cp < ctype+nelem(ctype)-1; cp++)
		cp->next = cp+1;

	if(singleton != nil){
		cur = dosingleton(&top, singleton);
		if(cur == nil){
			Bprint(&out, "no message\n");
			exitfs(0);
		}
		pcmd(nil, cur);
	} else {
		cur = &top;
		n = dir2message(&top, reverse);
		if(n < 0)
			sysfatal("can't read %s", s_to_c(top.path));
		Bprint(&out, "%d message%s\n", n, plural(n));
	}


	notify(catchnote);
	prompt = s_new();
	for(;;){
		s_reset(prompt);
		if(cur == &top)
			s_append(prompt, ": ");
		else {
			mkid(prompt, cur);
			s_append(prompt, ": ");
		}

		// leave space at the end of cmd line in case parsecmd needs to
		// add a space after a '|' or '!'
		if(readline(s_to_c(prompt), cmdline, sizeof(cmdline)-1) == nil)
			break;
		err = parsecmd(cmdline, &cmd, top.child, cur);
		if(err != nil){
			Bprint(&out, "!%s\n", err);
			continue;
		}
		if(singleton != nil && cmd.f == icmd){
			Bprint(&out, "!illegal command\n");
			continue;
		}
		interrupted = 0;
		if(cmd.msgs == nil || cmd.msgs == &top){
			x = (*cmd.f)(&cmd, &top);
			if(x != nil)
				cur = x;
		} else for(m = cmd.msgs; m != nil; m = m->cmd){
			x = m;
			if(cmd.delete){
				dcmd(&cmd, x);

				// dp acts differently than all other commands
				// since its an old lesk idiom that people love.
				// it deletes the current message, moves the current
				// pointer ahead one and prints.
				if(cmd.f == pcmd){
					if(x->next == nil){
						Bprint(&out, "!address\n");
						cur = x;
						break;
					} else
						x = x->next;
				}
			}
			x = (*cmd.f)(&cmd, x);
			if(x != nil)
				cur = x;
			if(interrupted)
				break;
			if(singleton != nil && (cmd.delete || cmd.f == dcmd))
				qcmd(nil, nil);
		}
		if(doflush)
			cur = flushdeleted(cur);
	}
	qcmd(nil, nil);
}

//
// read the message info
//
Message*
file2message(Message *parent, char *name)
{
	Message *m;
	String *path;
	char *f[10];

	m = mallocz(sizeof(Message), 1);
	if(m == nil)
		return nil;
	m->path = path = extendpath(parent->path, name);
	m->fileno = atoi(name);
	m->info = file2string(path, "info");
	lineize(s_to_c(m->info), f, nelem(f));
	m->from = f[0];
	m->to = f[1];
	m->cc = f[2];
	m->replyto = f[3];
	m->date = f[4];
	m->subject = f[5];
	m->type = f[6];
	m->disposition = f[7];
	m->filename = f[8];
	m->len = filelen(path, "raw");
	if(strstr(m->type, "multipart") != nil || strcmp(m->type, "message/rfc822") == 0)
		dir2message(m, 0);
	m->parent = parent;

	return m;
}

void
freemessage(Message *m)
{
	Message *nm, *next;

	for(nm = m->child; nm != nil; nm = next){
		next = nm->next;
		freemessage(nm);
	}
	s_free(m->path);
	s_free(m->info);
	free(m);
}

//
//  read a directory into a list of messages
//
int
dir2message(Message *parent, int reverse)
{
	int i, n, fd, highest, newmsgs;
	Dir *d;
	Message *first, *last, *m;

	fd = open(s_to_c(parent->path), OREAD);
	if(fd < 0)
		return -1;

	// count current entries
	first = parent->child;
	highest = newmsgs = 0;
	for(last = parent->child; last != nil && last->next != nil; last = last->next)
		if(last->fileno > highest)
			highest = last->fileno;
	if(last != nil)
		if(last->fileno > highest)
			highest = last->fileno;

	n = dirreadall(fd, &d);
	for(i = 0; i < n; i++){
		if((d[i].qid.type & QTDIR) == 0)
			continue;
		if(atoi(d[i].name) <= highest)
			continue;
		m = file2message(parent, d[i].name);
		if(m == nil)
			break;
		newmsgs++;
		if(reverse){
			m->next = first;
			if(first != nil)
				first->prev = m;
			first = m;
		} else {
			if(first == nil)
				first = m;
			else
				last->next = m;
			m->prev = last;
			last = m;
		}
	}
	free(d);
	close(fd);
	parent->child = first;

	// renumber and file longest from
	i = 1;
	longestfrom = 12;
	for(m = first; m != nil; m = m->next){
		m->id = natural ? m->fileno : i++;
		n = strlen(m->from);
		if(n > longestfrom)
			longestfrom = n;
	}

	return newmsgs;
}

//
//  point directly to a message
//
Message*
dosingleton(Message *parent, char *path)
{
	char *p, *np;
	Message *m;

	// walk down to message and read it
	if(strlen(path) < rootlen)
		return nil;
	if(path[rootlen] != '/')
		return nil;
	p = path+rootlen+1;
	np = strchr(p, '/');
	if(np != nil)
		*np = 0;
	m = file2message(parent, p);
	if(m == nil)
		return nil;
	parent->child = m;
	m->id = 1;

	// walk down to requested component
	while(np != nil){
		*np = '/';
		np = strchr(np+1, '/');
		if(np != nil)
			*np = 0;
		for(m = m->child; m != nil; m = m->next)
			if(strcmp(path, s_to_c(m->path)) == 0)
				return m;
		if(m == nil)
			return nil;
	}
	return m;
}

//
//  read a file into a string
//
String*
file2string(String *dir, char *file)
{
	String *s;
	int fd, n, m;

	s = extendpath(dir, file);
	fd = open(s_to_c(s), OREAD);
	s_grow(s, 512);			/* avoid multiple reads on info files */
	s_reset(s);
	if(fd < 0)
		return s;

	for(;;){
		n = s->end - s->ptr;
		if(n == 0){
			s_grow(s, 128);
			continue;
		}
		m = read(fd, s->ptr, n);
		if(m <= 0)
			break;
		s->ptr += m;
		if(m < n)
			break;
	}
	s_terminate(s);
	close(fd);

	return s;
}

//
//  get the length of a file
//
int
filelen(String *dir, char *file)
{
	String *path;
	Dir *d;
	int rv;

	path = extendpath(dir, file);
	d = dirstat(s_to_c(path));
	if(d == nil){
		s_free(path);
		return -1;
	}
	s_free(path);
	rv = d->length;
	free(d);
	return rv;
}

//
//  walk the path name an element
//
String*
extendpath(String *dir, char *name)
{
	String *path;

	if(strcmp(s_to_c(dir), ".") == 0)
		path = s_new();
	else {
		path = s_copy(s_to_c(dir));
		s_append(path, "/");
	}
	s_append(path, name);
	return path;
}

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;
}

char*
nosecs(char *t)
{
	char *p;

	p = strchr(t, ':');
	if(p == nil)
		return t;
	p = strchr(p+1, ':');
	if(p != nil)
		*p = 0;
	return t;
}

char *months[12] =
{
	"jan", "feb", "mar", "apr", "may", "jun",
	"jul", "aug", "sep", "oct", "nov", "dec"
};

int
month(char *m)
{
	int i;

	for(i = 0; i < 12; i++)
		if(cistrcmp(m, months[i]) == 0)
			return i+1;
	return 1;
}

enum
{
	Yearsecs= 365*24*60*60
};

void
cracktime(char *d, char *out, int len)
{
	char in[64];
	char *f[6];
	int n;
	Tm tm;
	long now, then;
	char *dtime;

	*out = 0;
	if(d == nil)
		return;
	strncpy(in, d, sizeof(in));
	in[sizeof(in)-1] = 0;
	n = getfields(in, f, 6, 1, " \t\r\n");
	if(n != 6){
		// unknown style
		snprint(out, 16, "%10.10s", d);
		return;
	}
	now = time(0);
	memset(&tm, 0, sizeof tm);
	if(strchr(f[0], ',') != nil && strchr(f[4], ':') != nil){
		// 822 style
		tm.year = atoi(f[3])-1900;
		tm.mon = month(f[2]);
		tm.mday = atoi(f[1]);
		dtime = nosecs(f[4]);
		then = tm2sec(&tm);
	} else if(strchr(f[3], ':') != nil){
		// unix style
		tm.year = atoi(f[5])-1900;
		tm.mon = month(f[1]);
		tm.mday = atoi(f[2]);
		dtime = nosecs(f[3]);
		then = tm2sec(&tm);
	} else {
		then = now;
		tm = *localtime(now);
		dtime = "";
	}

	if(now - then < Yearsecs/2)
		snprint(out, len, "%2d/%2.2d %s", tm.mon, tm.mday, dtime);
	else
		snprint(out, len, "%2d/%2.2d  %4d", tm.mon, tm.mday, tm.year+1900);
}

Ctype*
findctype(Message *m)
{
	char *p;
	char ftype[128];
	int n, pfd[2];
	Ctype *a, *cp;
	static Ctype nulltype	= { "", 0, 0, 0 };
	static Ctype bintype 	= { "application/octet-stream", "bin", 0, 0 };

	for(cp = ctype; cp; cp = cp->next)
		if(strncmp(cp->type, m->type, strlen(cp->type)) == 0)
			return cp;

/*	use file(1) for any unknown mimetypes
 *
 *	if (strcmp(m->type, bintype.type) != 0)
 *		return &nulltype;
 */
	if(pipe(pfd) < 0)
		return &bintype;

	*ftype = 0;
	switch(fork()){
	case -1:
		break;
	case 0:
		close(pfd[1]);
		close(0);
		dup(pfd[0], 0);
		close(1);
		dup(pfd[0], 1);
		execl("/bin/file", "file", "-m", s_to_c(extendpath(m->path, "body")), nil);
		exits(0);
	default:
		close(pfd[0]);
		n = read(pfd[1], ftype, sizeof(ftype));
		if(n > 0)
			ftype[n] = 0;
		close(pfd[1]);
		waitpid();
		break;
	}

	if (*ftype=='\0' || (p = strchr(ftype, '/')) == nil)
		return &bintype;
	*p++ = 0;

	a = mallocz(sizeof(Ctype), 1);
	a->type = strdup(ftype);
	a->ext = strdup(p);
	a->display = 0;
	a->plumbdest = strdup(ftype);
	for(cp = ctype; cp->next; cp = cp->next)
		continue;
	cp->next = a;
	a->next = nil;
	return a;
}

void
mkid(String *s, Message *m)
{
	char buf[32];

	if(m->parent != &top){
		mkid(s, m->parent);
		s_append(s, ".");
	}
	sprint(buf, "%d", m->id);
	s_append(s, buf);
}

void
snprintheader(char *buf, int len, Message *m)
{
	char timebuf[32];
	String *id;
	char *p, *q;;

	// create id
	id = s_new();
	mkid(id, m);

	if(*m->from == 0){
		// no from
		snprint(buf, len, "%-3s    %s %6d  %s",
			s_to_c(id),
			m->type,
			m->len,
			m->filename);
	} else if(*m->subject){
		q = p = strdup(m->subject);
		while(*p == ' ')
			p++;
		if(strlen(p) > 50)
			p[50] = 0;
		cracktime(m->date, timebuf, sizeof(timebuf));
		snprint(buf, len, "%-3s %c%c%c %6d  %11.11s %-*.*s %s",
			s_to_c(id),
			m->child ? 'H' : ' ',
			m->deleted ? 'd' : ' ',
			m->stored ? 's' : ' ',
			m->len,
			timebuf,
			longestfrom, longestfrom, m->from,
			p);
		free(q);
	} else {
		cracktime(m->date, timebuf, sizeof(timebuf));
		snprint(buf, len, "%-3s %c%c%c %6d  %11.11s %s",
			s_to_c(id),
			m->child ? 'H' : ' ',
			m->deleted ? 'd' : ' ',
			m->stored ? 's' : ' ',
			m->len,
			timebuf,
			m->from);
	}
	s_free(id);
}

char *spaces = "                                                                    ";

void
snprintHeader(char *buf, int len, int indent, Message *m)
{
	String *id;
	char typeid[64];
	char *p, *e;

	// create id
	id = s_new();
	mkid(id, m);

	e = buf + len;

	snprint(typeid, sizeof typeid, "%s    %s", s_to_c(id), m->type);
	if(indent < 6)
		p = seprint(buf, e, "%-32s %-6d ", typeid, m->len);
	else