On Sat, Mar 17, 2007 at 10:37:52PM -0400, tbert wrote:
> After a few days of digging in the VFS code, I've used the
> VOP* call that seems appropriate to populate bufs, vice
> the bread call I had before; I've added a quick'n'dirty
> readahead for performance reasons (or so I think...) and
> addressed a major oversight on my part concerning the lack
> of paying attention to the offset.

there is already a function that does the reading -- vn_rdwr.

> I'm still somewhat unsure as to how to deal with the error
> return from copyout vice the error return from sosendfile.
> Which is more important? Of course, this issue could be
> rendered entirely moot, as I'm starting to look towards
> emulating the Linux sendfile interface, as it is simpler
> and more consistent with the other send* functions in appearance
> and use.

well. it's easy -- you take errors as they come.

> I'd much appreciate any feedback on the API issue from the
> community, especially those of you maintaining network software.

why don't you read the existing source before you write anything?
and don't forget to write a test for it either.

> Index: src/sys/kern/uipc_syscalls.c
> ================================================== =================
> RCS file: /cvs/src/sys/kern/uipc_syscalls.c,v
> retrieving revision 1.66
> diff -u -r1.66 uipc_syscalls.c
> --- src/sys/kern/uipc_syscalls.c 23 Oct 2006 07:13:56 -0000 1.66
> +++ src/sys/kern/uipc_syscalls.c 19 Mar 2007 02:28:59 -0000
> @@ -47,6 +47,7 @@
> #include <sys/signalvar.h>
> #include <sys/unpcb.h>
> #include <sys/un.h>
> +#include <sys/vnode.h>
> #ifdef KTRACE
> #include <sys/ktrace.h>
> #endif
> @@ -1091,4 +1092,69 @@
> FREF(fp);
>
> return (0);
> +}
> +
> +int
> +sys_sendfile(struct proc *p, void* v, register_t *retval)
> +{
> + struct sys_sendfile_args /* {
> + syscallarg(int) fd;
> + syscallarg(int) s;
> + syscallarg(off_t) off;
> + syscallarg(size_t) nbytes;
> + syscallarg(off_t *) sbytes;
> + syscallarg(int) flags;
> + } */ *uap = v;
> + struct file *fp, *sp;
> + struct socket *so;
> + struct vnode *vp;
> + off_t *sbytes, sbtmp, off;
> + size_t nbytes;
> + int error, flags, fd, s;
> +
> + nbytes = SCARG(uap, nbytes);
> + sbytes = SCARG(uap, sbytes);
> + flags = SCARG(uap, flags);
> + off = SCARG(uap, off);
> + fd = SCARG(uap, fd);
> + s = SCARG(uap, s);
> +
> + /*
> + * Malicious or incorrect values
> + * may cause off + nbytes to wrap.
> + */
> + if (off < 0 || off + nbytes < off) {
> + error = EINVAL;
> + goto out;
> + }
> +
> + /* validate userspace pointer */
> + if (sbytes != NULL)
> + if ((error = copyin(sbytes, &sbtmp, sizeof(off_t))) != 0)
> + goto out;
> +
> + if ((error = getvnode(p->p_fd, fd, &fp)) != 0)
> + goto out;
> + vp = fp->f_data;
> +
> + if ((error = getsock(p->p_fd, s, &sp)) != 0)
> + goto vfail;
> + so = sp->f_data;
> +
> + if (!(so->so_type & SOCK_STREAM)) {
> + error = EINVAL;
> + goto sfail;
> + }
> +
> + error = sosendfile(so, vp, nbytes, &sbtmp, p, off, flags);
> +
> + if (sbytes != NULL)
> + copyout(&sbtmp, sbytes, sizeof(off_t));
> +
> +sfail:
> + FRELE(sp);
> +vfail:
> + FRELE(fp);
> +out:
> + return (error);
> }
> Index: src/sys/kern/uipc_socket.c
> ================================================== =================
> RCS file: /cvs/src/sys/kern/uipc_socket.c,v
> retrieving revision 1.66
> diff -u -r1.66 uipc_socket.c
> --- src/sys/kern/uipc_socket.c 26 Feb 2007 23:53:33 -0000 1.66
> +++ src/sys/kern/uipc_socket.c 19 Mar 2007 02:29:11 -0000
> @@ -47,6 +47,9 @@
> #include <sys/signalvar.h>
> #include <sys/resourcevar.h>
> #include <sys/pool.h>
> +#include <sys/buf.h>
> +#include <sys/vnode.h>
> +#include <sys/mount.h>
>
> void filt_sordetach(struct knote *kn);
> int filt_soread(struct knote *kn, long hint);
> @@ -54,6 +57,8 @@
> int filt_sowrite(struct knote *kn, long hint);
> int filt_solisten(struct knote *kn, long hint);
>
> +void sf_free_fbuf(caddr_t, u_int, void *);
> +
> struct filterops solisten_filtops =
> { 1, NULL, filt_sordetach, filt_solisten };
> struct filterops soread_filtops =
> @@ -1295,4 +1300,184 @@
>
> kn->kn_data = so->so_qlen;
> return (so->so_qlen != 0);
> +}
> +
> +/*
> + * Implement zero-copy file transmit over a socket.
> + *
> + * Socket MUST be SOCK_STREAM.
> + *
> + * File bufs are used as external data storage for mbufs,
> + * which are passed to the appropriate socket send routine.
> + *
> + * If a user has specified a number of bytes to send, transmit
> + * that amount of data; otherwise, send the entire file. Return
> + * the number of bytes sent in sbytes.
> + *
> + * Flags:
> + * SF_NODISKIO:
> + * return EBUSY instead of waiting
> + * for disk I/O to complete
> + */
> +#define SFRABLKS 2 /* better value is ??? */
> +int
> +sosendfile(struct socket *so, struct vnode *vp, size_t nbytes, off_t *sbytes,
> + struct proc *p, off_t off, int flags)
> +{
> + struct vattr va;
> + struct mbuf *m, *m0;
> + struct buf *bp, *bbp;
> + ssize_t space;
> + off_t resid, sent, sent0;
> + u_int sblk, eblk, len;
> + int error, i, j, s;
> +
> + sent = sent0 = 0;
> + m = NULL;
> +
> + s = splsoftnet();
> +
> + if ((error = sblock(&so->so_snd, M_WAITOK)) != 0)
> + goto out;
> +
> + if ((vn_lock(vp, (LK_EXCLUSIVE | LK_RETRY), p) != 0) ||
> + (VOP_GETATTR(vp, &va, p->p_ucred, p) != 0)) {
> + error = EIO;
> + goto release;
> + }
> +
> + /*
> + * off + nbytes wraparound validated in sys_sendfile()
> + */
> + if (off + nbytes > va.va_size) {
> + error = EINVAL;
> + goto release;
> + }
> +
> + if (nbytes > 0)
> + resid = nbytes;
> + else
> + resid = va.va_size - off;
> +
> + eblk = (u_int)((off + resid) / va.va_blocksize);
> + sblk = (u_int)(off / va.va_blocksize);
> + off -= sblk * va.va_blocksize;
> +
> + so->so_state |= SS_ISSENDING;
> +
> + for (i = sblk; i <= eblk {
> +
> + if (!(so->so_state & SS_ISCONNECTED))
> + error = ENOTCONN;
> + else if (so->so_state & SS_CANTSENDMORE)
> + error = EPIPE;
> + else if (so->so_error) {
> + error = so->so_error;
> + so->so_error = 0;
> + }
> + if (error)
> + goto release;
> +
> +retry:
> + space = sbspace(&so->so_snd);
> + if (space < so->so_snd.sb_lowat && space < resid) {
> + if ((error = sbwait(&so->so_snd)) != 0)
> + goto release;
> +
> + goto retry;
> + }
> + if (space > resid)
> + space = resid;
> +
> + while (space > 0) {
> +
> + bp = getblk(vp, i, va.va_blocksize, 0, 0);
> +
> + /*
> + * If it wasn't found in the cache, then disk I/O
> + * is needed; is that what the caller asked for?
> + */
> + if (!(bp->b_flags & (B_DONE | B_DELWRI))) {
> + if (flags & SF_NODISKIO) {
> + error = EBUSY;
> + brelse(bp);
> + goto release;
> + }
> + bp->b_flags |= B_READ;
> + VOP_STRATEGY(bp);
> + p->p_stats->p_ru.ru_inblock++;
> + }
> +
> + /* async readahead */
> + for (j = 1; j < min(eblk, i + SFRABLKS); j++) {
> + bbp = getblk(vp, i + j, va.va_blocksize, 0, 0);
> + if (!(bbp->b_flags & (B_DONE | B_DELWRI))) {
> + bbp->b_flags |= (B_READ | B_ASYNC);
> + VOP_STRATEGY(bbp);
> + p->p_stats->p_ru.ru_inblock++;
> + } else {
> + brelse(bbp);
> + }
> + }
> +
> + error = biowait(bp);
> + if (error) {
> + brelse(bp);
> + goto release;
> + }
> +
> + len = (u_int)bp->b_bcount - off;
> + if (len > resid)
> + len = (u_int)resid;
> +
> + if (m == NULL) {
> + MGETHDR(m0, M_WAITOK, MT_DATA);
> + m = m0;
> + m->m_pkthdr.rcvif = NULL;
> + m->m_pkthdr.len = 0;
> + } else {
> + MGET(m0, M_WAITOK, MT_DATA);
> + m_cat(m, m0);
> + }
> + MEXTADD(m0, bp->b_data + off, len,
> + M_FILE, sf_free_fbuf, bp);
> + m->m_pkthdr.len += len;
> +
> + sent0 += len;
> + resid -= len;
> + space -= len;
> + off = 0;
> + i++;
> + }
> +
> + error = (*so->so_proto->pr_usrreq)(so, PRU_SEND, m, NULL, NULL);
> + if (error)
> + goto release;
> +
> + m_freem(m);
> +
> + sent = sent0;
> + }
> +
> +release:
> + VOP_UNLOCK(vp, 0, p);
> + so->so_state &= ~SS_ISSENDING;
> + sbunlock(&so->so_snd);
> +out:
> + splx(s);
> + if (m != NULL)
> + m_freem(m);
> + *sbytes = sent;
> + return (error);
> +}
> +
> +/*
> + * Utility function to free file buffers
> + * as they are consumed in sosendfile.
> + */
> +/* ARGSUSED */
> +void
> +sf_free_fbuf(caddr_t buf, u_int size, void *arg)
> +{
> + brelse(arg);
> }
> Index: src/sys/kern/syscalls.master
> ================================================== =================
> RCS file: /cvs/src/sys/kern/syscalls.master,v
> retrieving revision 1.86
> diff -u -r1.86 syscalls.master
> --- src/sys/kern/syscalls.master 22 Sep 2006 17:35:41 -0000 1.86
> +++ src/sys/kern/syscalls.master 19 Mar 2007 02:29:26 -0000
> @@ -611,3 +611,5 @@
> 304 STD { int sys___getcwd(char *buf, size_t len); }
> 305 STD { int sys_adjfreq(const int64_t *freq, \
> int64_t *oldfreq); }
> +306 STD { int sys_sendfile(int fd, int s, off_t off, \
> + size_t nbytes, off_t *sbytes, int flags); }
> Index: src/sys/sys/socket.h
> ================================================== =================
> RCS file: /cvs/src/sys/sys/socket.h,v
> retrieving revision 1.53
> diff -u -r1.53 socket.h
> --- src/sys/sys/socket.h 31 Mar 2006 17:30:39 -0000 1.53
> +++ src/sys/sys/socket.h 19 Mar 2007 02:29:47 -0000
> @@ -436,6 +436,11 @@
>
> #define SA_LEN(x) ((x)->sa_len)
>
> +/*
> + * Sendfile flags.
> + */
> +#define SF_NODISKIO 0x0001
> +
> #ifndef _KERNEL
>
> #include <sys/cdefs.h>
> @@ -453,6 +458,7 @@
> ssize_t recvfrom(int, void *, size_t, int, struct sockaddr *, socklen_t *);
> ssize_t recvmsg(int, struct msghdr *, int);
> ssize_t send(int, const void *, size_t, int);
> +int sendfile(int, int, off_t, size_t, off_t *, int);
> ssize_t sendto(int, const void *,
> size_t, int, const struct sockaddr *, socklen_t);
> ssize_t sendmsg(int, const struct msghdr *, int);
> Index: src/sys/sys/socketvar.h
> ================================================== =================
> RCS file: /cvs/src/sys/sys/socketvar.h,v
> retrieving revision 1.39
> diff -u -r1.39 socketvar.h
> --- src/sys/sys/socketvar.h 26 Feb 2007 23:53:33 -0000 1.39
> +++ src/sys/sys/socketvar.h 19 Mar 2007 02:29:56 -0000
> @@ -37,6 +37,8 @@
>
> TAILQ_HEAD(soqhead, socket);
>
> +struct vnode;
> +
> /*
> * Kernel structure per socket.
> * Contains send and receive buffer queues,
> @@ -302,6 +304,8 @@
> void sorflush(struct socket *so);
> int sosend(struct socket *so, struct mbuf *addr, struct uio *uio,
> struct mbuf *top, struct mbuf *control, int flags);
> +int sosendfile(struct socket *so, struct vnode *vp, size_t nbytes,
> + off_t *sbytes, struct proc *p, off_t off, int flags);
> int sosetopt(struct socket *so, int level, int optname,
> struct mbuf *m0);
> int soshutdown(struct socket *so, int how);
> Index: src/lib/libc/sys/Makefile.inc
> ================================================== =================
> RCS file: /cvs/src/lib/libc/sys/Makefile.inc,v
> retrieving revision 1.80
> diff -u -r1.80 Makefile.inc
> --- src/lib/libc/sys/Makefile.inc 24 Oct 2006 04:40:59 -0000 1.80
> +++ src/lib/libc/sys/Makefile.inc 19 Mar 2007 02:30:52 -0000
> @@ -50,7 +50,8 @@
> munlock.o munlockall.o munmap.o nanosleep.o nfssvc.o \
> open.o pathconf.o pipe.o poll.o profil.o quotactl.o \
> read.o readlink.o readv.o reboot.o recvfrom.o recvmsg.o rename.o \
> - revoke.o rmdir.o select.o semget.o semop.o sendmsg.o sendto.o \
> + revoke.o rmdir.o select.o semget.o semop.o sendfile.o sendmsg.o \
> + sendto.o \
> setegid.o seteuid.o setgid.o setgroups.o setitimer.o setpgid.o \
> setpriority.o setregid.o setreuid.o setresgid.o setresuid.o \
> setrlimit.o setsid.o setsockopt.o settimeofday.o \
> Index: src/libexec/tftpd/tftpd.c
> ================================================== =================
> RCS file: /cvs/src/libexec/tftpd/tftpd.c,v
> retrieving revision 1.54
> diff -u -r1.54 tftpd.c
> --- src/libexec/tftpd/tftpd.c 15 Dec 2006 05:52:06 -0000 1.54
> +++ src/libexec/tftpd/tftpd.c 19 Mar 2007 02:31:28 -0000
> @@ -83,7 +83,7 @@
> __dead void usage(void);
> void tftp(struct tftphdr *, int);
> int validate_access(char *, int);
> -int sendfile(struct formats *);
> +int tftpd_sendfile(struct formats *);
> int recvfile(struct formats *);
> void nak(int);
> void oack(int);
> @@ -112,8 +112,8 @@
> int (*f_recv)(struct formats *);
> int f_convert;
> } formats[] = {
> - { "netascii", validate_access, sendfile, recvfile, 1 },
> - { "octet", validate_access, sendfile, recvfile, 0 },
> + { "netascii", validate_access, tftpd_sendfile, recvfile, 1 },
> + { "octet", validate_access, tftpd_sendfile, recvfile, 0 },
> { NULL, NULL, NULL, NULL, 0 }
> };
>
> @@ -603,7 +603,7 @@
> * Send the requested file.
> */
> int
> -sendfile(struct formats *pf)
> +tftpd_sendfile(struct formats *pf)
> {
> struct tftphdr *dp, *r_init(void);
> struct tftphdr *ap; /* ack packet */
> Index: src/usr.bin/tftp/main.c
> ================================================== =================
> RCS file: /cvs/src/usr.bin/tftp/main.c,v
> retrieving revision 1.28
> diff -u -r1.28 main.c
> --- src/usr.bin/tftp/main.c 26 Jul 2006 22:43:53 -0000 1.28
> +++ src/usr.bin/tftp/main.c 19 Mar 2007 02:32:32 -0000
> @@ -381,7 +381,7 @@
> printf("putting %s to %s:%s [%s]\n",
> cp, hostname, targ, mode);
> peeraddr.sin_port = port;
> - sendfile(fd, targ, mode);
> + tftp_sendfile(fd, targ, mode);
> return;
> }
>
> @@ -402,7 +402,7 @@
> printf("putting %s to %s:%s [%s]\n",
> argv[n], hostname, cp, mode);
> peeraddr.sin_port = port;
> - sendfile(fd, cp, mode);
> + tftp_sendfile(fd, cp, mode);
> free(cp);
> }
> }
> Index: src/usr.bin/tftp/tftp.c
> ================================================== =================
> RCS file: /cvs/src/usr.bin/tftp/tftp.c,v
> retrieving revision 1.20
> diff -u -r1.20 tftp.c
> --- src/usr.bin/tftp/tftp.c 26 Jul 2006 09:10:03 -0000 1.20
> +++ src/usr.bin/tftp/tftp.c 19 Mar 2007 02:34:41 -0000
> @@ -129,7 +129,7 @@
> * Send the requested file.
> */
> void
> -sendfile(int fd, char *name, char *mode)
> +tftp_sendfile(int fd, char *name, char *mode)
> {
> struct tftphdr *dp, *ap; /* data and ack packets */
> struct sockaddr_in from;
> Index: src/usr.bin/tftp/extern.h
> ================================================== =================
> RCS file: /cvs/src/usr.bin/tftp/extern.h,v
> retrieving revision 1.5
> diff -u -r1.5 extern.h
> --- src/usr.bin/tftp/extern.h 26 Jul 2006 16:43:31 -0000 1.5
> +++ src/usr.bin/tftp/extern.h 19 Mar 2007 02:35:58 -0000
> @@ -33,7 +33,7 @@
> */
>
> void recvfile(int, char *, char *);
> -void sendfile(int, char *, char *);
> +void tftp_sendfile(int, char *, char *);
>
> #define TIMEOUT 5 /* packet rexmt timeout */
> #define TIMEOUT_MIN 1 /* minimal packet rexmt timeout */
>

--
paranoic mickey (my employers have changed but, the name has remained)