shithub: 9pro

ref: c52cc89283ceb0106db86d332d5134c8b07d67e2
dir: /9pex.c/

#define _FILE_OFFSET_BITS 64
#include <errno.h>
#include <stdio.h>
#include <stdint.h>
#include <dirent.h>
#include <fcntl.h>
#include <aio.h>
#include <signal.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
#include "c9.h"

#define max(a,b) ((a)>(b)?(a):(b))
#define used(x) ((void)(x))
#define nelem(x) (int)(sizeof(x)/sizeof((x)[0]))

enum
{
	Canrd = 1<<0,
	Canwr = 1<<1,
};

typedef struct
{
	char *path; /* full path */
	char *name; /* base name */

	DIR *dir; /* set when it's an opened directory */
	uint64_t diroffset; /* to read dirs correctly */

	C9qid qid;
	C9fid fid;
	C9mode mode; /* mode in which the file was opened */
	uint32_t iounit;

	int fd; /* set when it's an opened file */
}Fid;

typedef struct
{
	C9tag tag;
}Tag;

static char *t2s[] = {
	[Tversion-Tversion] "Tversion",
	[Tauth-Tversion]    "Tauth",
	[Tattach-Tversion]  "Tattach",
	[Tflush-Tversion]   "Tflush",
	[Twalk-Tversion]    "Twalk",
	[Topen-Tversion]    "Topen",
	[Tcreate-Tversion]  "Tcreate",
	[Tread-Tversion]    "Tread",
	[Twrite-Tversion]   "Twrite",
	[Tclunk-Tversion]   "Tclunk",
	[Tremove-Tversion]  "Tremove",
	[Tstat-Tversion]    "Tstat",
	[Twstat-Tversion]   "Twstat",
};

static char *Enoauth = "authentication not required";
static char *Eunknownfid = "unknown fid";
static char *Enowstat = "wstat prohibited";
static char *Eperm = "permission denied";
static char *Enowrite = "write prohibited";
static char *Enomem = "out of memory";
static char *Edupfid = "duplicate fid";
static char *Ewalknodir = "walk in non-directory";
static char *Enotfound = "file not found";
static char *Eduptag = "duplicate tag";
static char *Ebotch = "9P protocol botch";
static char *Enocreate = "create prohibited";
static char *Eisdir = "is a directory";
static char *Ebadoffset = "bad offset";

static int in, out;
static C9ctx ctx;
static int debug = 1;
static Fid **fids;
static int numfids;
static Tag **tags;
static int numtags;
static char *rootpath;
static size_t rootlen;
static C9qid walkqids[C9maxpathel];
static uint8_t *rdbuf;
static uint8_t *wrbuf;
static int wroff;

static void
trace(const char *fmt, ...)
{
	va_list ap;

	if (debug == 0)
		return;

	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	va_end(ap);
}

static int
canrw(int rdonly)
{
	struct timeval t;
	fd_set r, w, e;
	int n, fl;

	FD_ZERO(&r);
	FD_SET(in, &r);
	if (rdonly == 0) {
		FD_ZERO(&w);
		FD_SET(out, &w);
	}
	FD_ZERO(&e);
	FD_SET(in, &e);
	FD_SET(out, &e);
	memset(&t, 0, sizeof(t));
	t.tv_usec = 1000;
	if ((n = select(max(in, out) + 1, &r, &w, &e, rdonly ? NULL : &t)) < 0 || FD_ISSET(in, &e) || FD_ISSET(out, &e))
		return -1;

	fl = 0;
	if (FD_ISSET(in, &r))
		fl |= Canrd;
	if (FD_ISSET(out, &w))
		fl |= Canwr;

	return fl;
}

static int
hastag(C9tag tag)
{
	int i;

	for (i = 0; i < numtags; i++) {
		if (tags[i] != NULL && tags[i]->tag == tag)
			return 1;
	}

	return 0;
}

static int
statpath(char *path, struct stat *st, char **err)
{
	if (stat(path, st) == 0)
		return 0;

	if (errno == EACCES)
		*err = Eperm;
	else if (errno == ENOMEM)
		*err = Enomem;
	else if (errno == ENOTDIR)
		*err = Ewalknodir;
	else if (errno == ENOENT)
		*err = Enotfound;
	else
		*err = strerror(errno);

	return -1;
}

static void
stat2qid(struct stat *st, C9qid *qid, uint32_t *iounit)
{
	int fmt;

	qid->path = st->st_ino;
	qid->version = st->st_mtime; /* no. */
	fmt = st->st_mode & S_IFMT;
	if (fmt == S_IFDIR)
		qid->type |= C9qtdir;
	if (fmt == S_IFCHR || fmt == S_IFCHR || fmt == S_IFSOCK || fmt == S_IFIFO)
		qid->type |= C9qtappend;
	if (iounit != NULL)
		*iounit = st->st_blksize;
}

static Fid *
newfid(C9fid fid, char *path, char **err)
{
	Fid *f, **newfids;
	struct stat st;
	int i;

	for (i = 0; i < numfids; i++) {
		if (fids[i] != NULL && fids[i]->fid == fid) {
			*err = Edupfid;
			return NULL;
		}
	}

	if (statpath(path, &st, err) != 0)
		return NULL;

	if ((f = calloc(1, sizeof(*f))) == NULL) {
		*err = Enomem;
		return NULL;
	}
	f->fd = -1;
	f->path = strdup(path);
	f->name = strrchr(f->path, '/');
	if (f->name == NULL)
		f->name = f->path;
	else
		f->name++;

	for (i = 0; i < numfids; i++) {
		if (fids[i] == NULL) {
			fids[i] = f;
			break;
		}
	}
	if (i >= numfids) {
		if ((newfids = realloc(fids, (numfids+1)*sizeof(*fids))) == NULL) {
			*err = Enomem;
			return NULL;
		}
		fids = newfids;
		fids[numfids++] = f;
	}

	f->fid = fid;
	stat2qid(&st, &f->qid, &f->iounit);

	return f;
}

static Fid *
findfid(C9fid fid, char **err)
{
	int i;

	for (i = 0; i < numfids; i++) {
		if (fids[i] != NULL && fids[i]->fid == fid) {
			return fids[i];
		}
	}

	*err = Eunknownfid;

	return NULL;
}

static int
delfid(C9fid fid, char **err)
{
	Fid *f;
	int i;

	for (i = 0; i < numfids; i++) {
		f = fids[i];
		if (f != NULL && f->fid == fid) {
			if (f->dir != NULL)
				closedir(f->dir);
			else if (f->fd >= 0)
				close(f->fd);
			free(f->path);
			free(f);
			fids[i] = NULL;
			return 0;
		}
	}

	*err = Eunknownfid;

	return -1;
}

static Fid *
walk(C9fid fid, C9fid nfid, char *el[], C9qid *qids[], char **err)
{
	Fid *f;
	char *path, *real, *p;
	struct stat st;
	int i, plen, ellen;

	if ((f = findfid(fid, err)) == NULL)
		return NULL;

	if (el[0] == NULL) { /* nwname = 0 */
		qids[0] = NULL;
		if (fid == nfid)
			return f;
		return newfid(nfid, f->path, err);
	}

	if ((f->qid.type & C9qtdir) == 0) { /* has to be a dir */
		*err = Ewalknodir;
		return NULL;
	}

	p = strdup(f->path);
	f = NULL;
	for (i = 0; el[i] != NULL; i++) {
		plen = strlen(p);
		ellen = strlen(el[i]);
		path = malloc(plen + 1 + ellen + 1);
		memmove(path, p, plen);
		path[plen] = '/';
		memmove(path+plen+1, el[i], ellen);
		path[plen+1+ellen] = 0;

		if ((real = realpath(path, NULL)) == NULL)
			break;
		if (strlen(real) < rootlen) { /* don't escape root */
			free(real);
			real = strdup(rootpath);
		}
		free(p);
		p = real;

		if (statpath(p, &st, err) != 0)
			break;
		qids[i] = &walkqids[i];
		stat2qid(&st, qids[i], NULL);
	}

	qids[i] = NULL;
	if (el[i] == NULL) { /* could walk all the way */
		f = newfid(nfid, p, err);
		if (f != NULL && f->name[0] == '/' && f->name[1] == 0) /* root */
			f->name = "/";
	} else if (i != 0) { /* didn't fail on the first one */
		*err = NULL;
	}
	free(p);

	return f;
}

static int
openfid(Fid *f, C9mode mode, char **err)
{
	struct stat st;
	int omode;

	if ((f->qid.type & C9qtdir) != 0) {
		if ((f->dir = opendir(f->path)) == NULL) {
			*err = strerror(errno);
			return -1;
		}
		f->fd = dirfd(f->dir);
	} else {
		omode = O_RDONLY;
		if ((f->qid.type & C9qtappend) != 0)
			omode |= O_APPEND;
		f->fd = open(f->path, omode);
	}

	if (f->fd < 0 || fstat(f->fd, &st) != 0) {
		*err = strerror(errno);

		if (f->dir != NULL)
			closedir(f->dir);
		else if (f->fd >= 0)
			close(f->fd);

		f->dir = NULL;
		f->fd = -1;
		return -1;
	}
	stat2qid(&st, &f->qid, &f->iounit);
	f->mode = mode;

	return 0;
}

static char *
uid2str(uid_t uid, char **err)
{
	struct passwd *p;

	if ((p = getpwuid(uid)) == NULL)
		*err = strerror(errno);
	else
		return p->pw_name;

	return NULL;
}

static char *
gid2str(gid_t gid, char **err)
{
	struct group *g;

	if ((g = getgrgid(gid)) == NULL)
		*err = strerror(errno);
	else
		return g->gr_name;

	return NULL;
}

static int
stat2c9stat(char *name, struct stat *st, C9stat *out, char **err)
{
	int fmt;

	memset(out, 0, sizeof(*out));
	out->size = st->st_size;
	stat2qid(st, &out->qid, NULL);
	out->name = name;
	out->atime = st->st_atime;
	out->mtime = st->st_ctime;

	fmt = st->st_mode & S_IFMT;
	if (fmt == S_IFDIR)
		out->mode |= C9stdir;
	if (fmt == S_IFCHR || fmt == S_IFCHR || fmt == S_IFSOCK || fmt == S_IFIFO)
		out->mode |= C9stappend;
	out->mode |= st->st_mode & 0x1ff;
	if ((out->uid = uid2str(st->st_uid, err)) == NULL)
		return -1;
	if ((out->gid = gid2str(st->st_gid, err)) == NULL)
		return -1;

	return 0;
}

static int
statfid(Fid *f, C9stat *out, char **err)
{
	struct stat st;
	int r;

	if (f->fd >= 0)
		r = fstat(f->fd, &st);
	else
		r = stat(f->path, &st);
	if (r != 0) {
		*err = strerror(errno);
		return -1;
	}

	return stat2c9stat(f->name, &st, out, err);
}

static uint8_t *
ctxread(C9ctx *c, uint32_t size, int *err)
{
	int n;

	used(c);
	*err = 0;
	if ((n = read(in, rdbuf, size)) != (int)size) { /* unexpected eof */
		*err = 1;
		return NULL;
	}

	return rdbuf;
}

static uint8_t *
ctxbegin(C9ctx *c, uint32_t size)
{
	uint8_t *b;

	used(c);
	b = wrbuf + wroff;
	wroff += size;

	return b;
}

static int
ctxend(C9ctx *c)
{
	used(c);

	if (write(out, wrbuf, wroff) != wroff)
		return -1;
	wroff = 0;

	return 0;
}

static int
readf(C9ctx *c, C9tag tag, Fid *f, uint64_t offset, uint32_t size, char **err)
{
	struct stat st;
	void *p;
	struct dirent *e;
	ssize_t n;
	C9stat c9st[16], *c9stp[16];
	long dirpos[16];
	int i, num;

	if (size > c->msize - 12) /* make sure it fits */
		size = c->msize - 12;

	if (f->dir == NULL) { /* a file */
		if ((p = malloc(size)) == NULL) {
			*err = Enomem;
			return -1;
		}
		if ((n = pread(f->fd, p, size, offset)) < 0) {
			*err = strerror(errno);
			return -1;
		}
		s9read(c, tag, p, n);
		return 0;
	}

	/* dir */
	if (offset != f->diroffset) {
		if (offset == 0) {
			rewinddir(f->dir);
			f->diroffset = 0;
		} else {
			*err = Ebadoffset;
			return -1;
		}
	}

	for (i = 0; i < nelem(c9st); i++) {
		dirpos[i] = telldir(f->dir); /* so we can rewind in case another stat doesn't fit */

		errno = 0;
		if ((e = readdir(f->dir)) == NULL && errno != 0) {
			*err = strerror(errno);
			return -1;
		}
		if (e == NULL) /* eof */
			break;

		if (fstatat(f->fd, e->d_name, &st, 0) != 0) {
			*err = strerror(errno);
			return -1;
		}
		if (stat2c9stat(e->d_name, &st, &c9st[i], err) != 0)
			return -1;
		c9stp[i] = &c9st[i];
	}

	num = i;
	if (s9readdir(c, tag, c9stp, &num, &f->diroffset, size) != 0)
		return -1;
	trace("<- Rread tag=%d ...\n", tag);
	seekdir(f->dir, dirpos[num]);

	return 0;
}

static int
s9do(C9error e, char **err)
{
	if (e == 0) {
		*err = NULL;
		return 0;
	}

	switch (e) {
	case C9Einit: *err = "c9: initialization failed"; break;
	case C9Ever: *err = "c9: protocol version doesn't match"; break;
	case C9Epkt: *err = "c9: incoming packet error"; break;
	case C9Etag: *err = "c9: no free tags or bad tag"; break;
	case C9Ebuf: *err = Enomem; break;
	case C9Epath: *err = "c9: path is too long or just invalid"; break;
	case C9Eflush: *err = "c9: limit of outstanding flushes reached"; break;
	case C9Esize: *err = "c9: can't fit data in one message"; break;
	case C9Estr: *err = "c9: bad string"; break;
	default: *err = "c9: unknown error"; break;
	}

	return -1;
}

static void
ctxt(C9ctx *c, C9t *t)
{
	Fid *f;
	C9qid *qids[C9maxpathel+1];
	char *err;
	C9stat st;
	int i;

	trace("-> %s tag=%d", t2s[t->type-Tversion], t->tag);

	err = NULL;
	if (hastag(t->tag)) {
		err = Eduptag;
	} else {
		switch (t->type){
		case Tversion:
			trace("\n");
			if (s9do(s9version(c), &err) == 0)
				trace("<- Rversion\n");
			break;
		case Tauth:
			trace(" afid=%d uname=\"%s\" aname=\"%s\"\n", t->auth.afid, t->auth.uname, t->auth.aname);
			err = Enoauth;
			break;
		case Tattach:
			trace(" afid=%d fid=%d uname=\"%s\" aname=\"%s\"\n", t->attach.afid, t->fid, t->attach.uname, t->attach.aname);
			if (t->attach.afid != C9nofid) {
				err = Eunknownfid;
			} else if ((f = newfid(t->fid, ".", &err)) != NULL) {
				f->name = "/";
				if (s9do(s9attach(c, t->tag, &f->qid), &err) == 0)
					trace("<- Rattach\n");
			}
			break;
		case Tflush:
			trace(" oldtag=%d\n", t->flush.oldtag);
			/* FIXME flush it for realz */
			if (s9do(s9flush(c, t->tag), &err) == 0)
				trace("<- Rflush tag=%d\n", t->tag);
			break;
		case Twalk:
			trace(" fid=%d newfid=%d", t->fid, t->walk.newfid);
			for (i = 0; t->walk.wname[i] != NULL; i++)
				trace(" \"%s\"", t->walk.wname[i]);
			trace("\n");
			walk(t->fid, t->walk.newfid, t->walk.wname, qids, &err);
			if (err == NULL && s9do(s9walk(c, t->tag, qids), &err) == 0)
				trace("<- Rwalk tag=%d ...\n", t->tag);
			break;
		case Topen:
			trace(" fid=%d mode=0x%02x\n", t->fid, t->open.mode);
			if ((f = findfid(t->fid, &err)) != NULL) {
				if (f->fd >= 0)
					err = Ebotch;
				else if (t->open.mode != C9read && t->open.mode != C9exec)
					err = Eperm;
				else if (t->open.mode != C9read && (f->qid.type & C9qtdir) != 0)
					err = Eisdir;
				else if (openfid(f, t->open.mode, &err) == 0 && s9do(s9open(c, t->tag, &f->qid, f->iounit), &err) == 0)
					trace("<- Ropen tag=%d iounit=%d ...\n", t->tag, f->iounit);
			}
			break;
		case Tcreate:
			trace("...\n");
			err = Enocreate;
			break;
		case Tread:
			trace(" fid=%d offset=%lld count=%d\n", t->fid, t->read.offset, t->read.size);
			if ((f = findfid(t->fid, &err)) != NULL) {
				if ((f->dir == NULL && f->fd < 0) || (f->mode & 0xf) == C9write)
					err = Ebotch;
				else if (readf(c, t->tag, f, t->read.offset, t->read.size, &err) != 0)
					trace("readf failed\n");
			}
			break;
		case Twrite:
			trace("...\n");
			err = Enowrite;
			break;
		case Tclunk:
			trace("\n");
			if (delfid(t->fid, &err) == 0 && s9do(s9clunk(c, t->tag), &err) == 0)
				trace("<- Rclunk tag=%d\n", t->tag);
			break;
		case Tremove:
			trace("\n");
			err = Eperm;
			break;
		case Tstat:
			trace(" fid=%d\n", t->fid);
			if ((f = findfid(t->fid, &err)) != NULL && statfid(f, &st, &err) == 0 && s9do(s9stat(c, t->tag, &st), &err) == 0)
				trace("<- Rstat tag=%d ...\n", t->tag);
			break;
		case Twstat:
			trace("...\n");
			err = Enowstat;
			break;
		}
	}

	if (err != NULL) {
		if (s9error(c, t->tag, err) == 0)
			trace("<- Rerror tag=%d \"%s\"\n", t->tag, err);
		else
			trace("failed to send an error response\n");
	}
}

int
main(int argc, char **argv)
{
	int can;

	used(argc); used(argv);

	rootpath = realpath(".", NULL);
	rootlen = strlen(rootpath);

	in = 0;
	out = 1;
	fids = NULL;
	numfids = 0;
	tags = NULL;
	numtags = 0;

	memset(&ctx, 0, sizeof(ctx));
	ctx.msize = 64*1024;
	ctx.read = ctxread;
	ctx.begin = ctxbegin;
	ctx.end = ctxend;
	ctx.t = ctxt;
	ctx.error = trace;

	rdbuf = malloc(ctx.msize);
	wrbuf = malloc(ctx.msize);
	wroff = 0;

	for (;;) {
		if ((can = canrw(1)) < 0)
			break;
		if ((can & Canrd) != 0 && s9proc(&ctx) != 0)
			break;
	}

	return 0;
}