1 files changed, 416 insertions, 0 deletions
diff --git a/usr/src/uts/common/brand/lx/syscall/lx_getdents.c b/usr/src/uts/common/brand/lx/syscall/lx_getdents.c
new file mode 100644
index 0000000000..5bde892aea
--- /dev/null
+++ b/usr/src/uts/common/brand/lx/syscall/lx_getdents.c
@@ -0,0 +1,416 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2017 Joyent, Inc.
+ */
+
+#include <sys/systm.h>
+#include <sys/filio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/inttypes.h>
+#include <sys/vnode.h>
+#include <sys/dirent.h>
+#include <sys/errno.h>
+#include <sys/file.h>
+#include <sys/sysmacros.h>
+#include <sys/kmem.h>
+#include <sys/sunddi.h>
+
+#include <sys/lx_types.h>
+#include <sys/lx_misc.h>
+
+#define	LX_NAMEMAX	256
+
+#define	LX_GETDENTS_MAX_BUFSZ	65536
+
+/*
+ * See the comment in our lx_sysfs VFS code for a detailed explanation around
+ * the handling of 'd_type' here.
+ */
+#define	LX_DT_UNKNOWN	0
+#define	LX_DT_FIFO	1
+#define	LX_DT_CHR	2
+#define	LX_DT_DIR	4
+#define	LX_DT_BLK	6
+#define	LX_DT_REG	8
+#define	LX_DT_LNK	10
+#define	LX_DT_SOCK	12
+
+/*
+ * Set by lx_sysfs when it loads. lx_sysfs depends on the lx_brand module,
+ * so our module has to load first and define the variables that lx_sysfs will
+ * set when it loads.
+ */
+int lx_sysfs_vfs_type;
+int (*lx_sysfs_vtype)(ino_t);
+
+/*
+ * Because the Linux dirent has an extra field (d_type), it's possible that
+ * each entry will be 8 bytes larger (and aligned to 8 bytes) due to padding.
+ * To prevent overrun during translation, the illumos-native buffer is sized
+ * pessimistically.
+ */
+#define	LTOS_GETDENTS_BUFSZ(bufsz, datasz)	\
+	(((bufsz) / (((datasz) + 15) & ~7)) * sizeof (struct dirent))
+
+/*
+ * Linux d_type offset is at (d_reclen - 1). See the Linux getdents(2) man page.
+ * This macro assumes d_reclen is already set correctly.
+ */
+#define	LX_DTYPE(l) *(((char *)l) + (l->d_reclen - 1))
+
+/*
+ * Record must be long enough to house d_name string, null terminator and
+ * d_type field.  It's then padded to nearest 8-byte boundary
+ */
+#define	LX_RECLEN(l, t)	\
+	((offsetof(t, d_name) + 2 + (l) + 7) & ~7)
+
+/*
+ * Bytes after d_name string until d_reclen should be zeroed.
+ * Includes zero-terminating d_name
+ */
+#define	LX_ZEROLEN(l, t)	\
+	(LX_RECLEN(l, t) -	\
+	((offsetof(t, d_name) + (l))))
+
+/* The output format of getdents differs if the caller is 32 or 64 bit. */
+struct lx_dirent_32 {
+	uint32_t	d_ino;
+	int32_t		d_off;
+	ushort_t	d_reclen;
+	char		d_name[1];
+	uchar_t		d_type;
+};
+
+struct lx_dirent_64 {
+	uint64_t	d_ino;
+	int64_t		d_off;
+	ushort_t	d_reclen;
+	char		d_name[1];
+	uchar_t		d_type;
+};
+
+static long
+lx_getdents_common(int fd, caddr_t uptr, size_t count,
+    unsigned int lx_size, int (*outcb)(caddr_t, caddr_t, int, boolean_t))
+{
+	vnode_t *vp;
+	boolean_t is_sysfs = B_FALSE;
+	file_t *fp;
+	struct uio auio;
+	struct iovec aiov;
+	int error, at_eof;
+	int sbufsz, lbufsz, bufsz;
+	void *lbuf, *sbuf;
+	size_t outb = 0;
+
+	if (count < lx_size) {
+		return (set_errno(EINVAL));
+	}
+	if ((fp = getf(fd)) == NULL) {
+		return (set_errno(EBADF));
+	}
+	vp = fp->f_vnode;
+	if (vp->v_type != VDIR) {
+		releasef(fd);
+		return (set_errno(ENOTDIR));
+	}
+	if (!(fp->f_flag & FREAD)) {
+		releasef(fd);
+		return (set_errno(EBADF));
+	}
+
+	if (vp->v_vfsp->vfs_fstype == lx_sysfs_vfs_type) {
+		is_sysfs = B_TRUE;
+	}
+
+	if (count > LX_GETDENTS_MAX_BUFSZ) {
+		/*
+		 * If the target buffer passed to us is huge, keep the
+		 * translation buffers moderate in size.  Iteration will be
+		 * used to fill the request.
+		 */
+		lbufsz = LX_GETDENTS_MAX_BUFSZ;
+		sbufsz = LTOS_GETDENTS_BUFSZ(LX_GETDENTS_MAX_BUFSZ, lx_size);
+	} else if (count < (lx_size + MAXPATHLEN)) {
+		/*
+		 * If the target buffer is tiny, allocate a Linux-format buffer
+		 * big enough to hold at least one max-length row while keeping
+		 * the illumos-format buffer pesimistic in size.
+		 *
+		 * Assuming the buffer is truely tiny, it's likely that the
+		 * result will not fit and an EINVAL will be tossed.
+		 */
+		lbufsz = (lx_size + MAXPATHLEN);
+		sbufsz = MAX((LTOS_GETDENTS_BUFSZ(count, lx_size)),
+		    sizeof (struct dirent));
+	} else {
+		lbufsz = count;
+		sbufsz = LTOS_GETDENTS_BUFSZ(count, lx_size);
+	}
+	bufsz = sbufsz;
+	lbuf = kmem_alloc(lbufsz, KM_SLEEP);
+	sbuf = kmem_alloc(sbufsz, KM_SLEEP);
+
+	aiov.iov_base = sbuf;
+	aiov.iov_len = sbufsz;
+	auio.uio_iov = &aiov;
+	auio.uio_iovcnt = 1;
+	auio.uio_loffset = fp->f_offset;
+	auio.uio_segflg = UIO_SYSSPACE;
+	auio.uio_resid = sbufsz;
+	auio.uio_fmode = 0;
+	auio.uio_extflg = UIO_COPY_CACHED;
+
+	/*
+	 * Since we use a conservative buffer allocation for the differing
+	 * struct sizing and Linux places fewer limits on getdents buffers in
+	 * general, there's a chance we'll undershoot on the record count.
+	 * When this happens, we can simply repeat the READDIR operation until
+	 * the available records are exhausted or we've filled the user buffer.
+	 */
+	do {
+		int res;
+
+		(void) VOP_RWLOCK(vp, V_WRITELOCK_FALSE, NULL);
+		error = VOP_READDIR(vp, &auio, fp->f_cred, &at_eof, NULL, 0);
+		VOP_RWUNLOCK(vp, V_WRITELOCK_FALSE, NULL);
+		if (error != 0 || auio.uio_resid == sbufsz) {
+			break;
+		}
+		res = outcb(sbuf, lbuf, bufsz - auio.uio_resid, is_sysfs);
+		VERIFY(res <= lbufsz);
+		if (res == 0) {
+			/* no records to copyout from this batch */
+			break;
+		} else if (res > count) {
+			/*
+			 * For very small buffer sizes, it's possible that a
+			 * single record is too large due to a long filename.
+			 */
+			error = EINVAL;
+			break;
+		}
+
+		VERIFY(outb + res <= count);
+		if (copyout(lbuf, (void *)(uptr + outb), res) != 0) {
+			error = EFAULT;
+			break;
+		}
+		outb += res;
+
+		/*
+		 * We undershot the request buffer.
+		 * Reset for another READDIR, taking care not to overshoot.
+		 */
+		bufsz = MIN(sbufsz, LTOS_GETDENTS_BUFSZ(count - outb, lx_size));
+		auio.uio_resid = bufsz;
+		aiov.iov_len = bufsz;
+		aiov.iov_base = sbuf;
+
+		/*
+		 * Continued progress is allowed only if EOF has not been
+		 * reached and there is enough remaining buffer space to hold
+		 * an entry with a max-length filename.
+		 */
+	} while (at_eof == 0 && (count - outb) >= (lx_size + MAXPATHLEN));
+
+	kmem_free(lbuf, lbufsz);
+	kmem_free(sbuf, sbufsz);
+
+	if (error) {
+		releasef(fd);
+		return (set_errno(error));
+	}
+
+	fp->f_offset = auio.uio_loffset;
+	releasef(fd);
+	return (outb);
+}
+
+static int
+lx_get_sysfs_dtype(ino_t ino)
+{
+	vtype_t vt;
+
+	vt = lx_sysfs_vtype(ino);
+
+	switch (vt) {
+	case VREG:	return (LX_DT_REG);
+	case VDIR:	return (LX_DT_DIR);
+	case VBLK:	return (LX_DT_BLK);
+	case VCHR:	return (LX_DT_CHR);
+	case VLNK:	return (LX_DT_LNK);
+	case VFIFO:	return (LX_DT_FIFO);
+	case VSOCK:	return (LX_DT_SOCK);
+	default:	return (LX_DT_UNKNOWN);
+	}
+}
+
+static int
+lx_getdents_format32(caddr_t sbuf, caddr_t lbuf, int len, boolean_t is_sysfs)
+{
+	struct dirent *sd;
+	struct lx_dirent_32 *ld;
+	int namelen;
+	int size = 0;
+
+	while (len > 0) {
+		/* LINTED: alignment */
+		sd = (struct dirent *)sbuf;
+		/* LINTED: alignment */
+		ld = (struct lx_dirent_32 *)lbuf;
+		namelen = MIN(strlen(sd->d_name), LX_NAMEMAX - 1);
+
+		ld->d_ino = sd->d_ino;
+		ld->d_off = sd->d_off;
+		(void) strncpy(ld->d_name, sd->d_name, namelen);
+		ld->d_name[namelen] = 0;
+		ld->d_reclen = (ushort_t)LX_RECLEN(namelen,
+		    struct lx_dirent_32);
+		/* Zero out any alignment padding and d_type */
+		bzero(ld->d_name + namelen,
+		    LX_ZEROLEN(namelen, struct lx_dirent_32));
+
+		if (is_sysfs) {
+			LX_DTYPE(ld) = lx_get_sysfs_dtype(ld->d_ino);
+		}
+
+		len -= sd->d_reclen;
+		size += ld->d_reclen;
+		sbuf += sd->d_reclen;
+		lbuf += ld->d_reclen;
+	}
+	return (size);
+}
+
+static int
+lx_getdents_format64(caddr_t sbuf, caddr_t lbuf, int len, boolean_t is_sysfs)
+{
+	struct dirent *sd;
+	struct lx_dirent_64 *ld;
+	int namelen;
+	int size = 0;
+
+	while (len > 0) {
+		/* LINTED: alignment */
+		sd = (struct dirent *)sbuf;
+		/* LINTED: alignment */
+		ld = (struct lx_dirent_64 *)lbuf;
+		namelen = MIN(strlen(sd->d_name), LX_NAMEMAX - 1);
+
+		ld->d_ino = sd->d_ino;
+		ld->d_off = sd->d_off;
+		(void) strncpy(ld->d_name, sd->d_name, namelen);
+		ld->d_name[namelen] = 0;
+		ld->d_reclen = (ushort_t)LX_RECLEN(namelen,
+		    struct lx_dirent_64);
+		/* Zero out any alignment padding and d_type */
+		bzero(ld->d_name + namelen,
+		    LX_ZEROLEN(namelen, struct lx_dirent_64));
+
+		if (is_sysfs) {
+			LX_DTYPE(ld) = lx_get_sysfs_dtype(ld->d_ino);
+		}
+
+		len -= sd->d_reclen;
+		size += ld->d_reclen;
+		sbuf += sd->d_reclen;
+		lbuf += ld->d_reclen;
+	}
+	return (size);
+}
+
+long
+lx_getdents_32(int fd, caddr_t buf, size_t count)
+{
+	return (lx_getdents_common(fd, buf, count,
+	    sizeof (struct lx_dirent_32), lx_getdents_format32));
+}
+
+long
+lx_getdents_64(int fd, caddr_t buf, size_t count)
+{
+	return (lx_getdents_common(fd, buf, count,
+	    sizeof (struct lx_dirent_64), lx_getdents_format64));
+}
+
+struct lx_dirent64 {
+	uint64_t	d_ino;
+	int64_t		d_off;
+	ushort_t	d_reclen;
+	uchar_t		d_type;
+	char		d_name[1];
+};
+
+#define	LX_RECLEN64(namelen)	\
+	((offsetof(struct lx_dirent64, d_name) + 1 + (namelen) + 7) & ~7)
+
+#define	LX_ZEROLEN64(namelen)	\
+	(LX_RECLEN64(namelen) -	\
+	((offsetof(struct lx_dirent64, d_name) + (namelen))))
+
+static int
+lx_getdents64_format(caddr_t sbuf, caddr_t lbuf, int len, boolean_t is_sysfs)
+{
+	struct dirent *sd;
+	struct lx_dirent64 *ld;
+	int namelen;
+	int size = 0;
+
+	while (len > 0) {
+		/* LINTED: alignment */
+		sd = (struct dirent *)sbuf;
+		/* LINTED: alignment */
+		ld = (struct lx_dirent64 *)lbuf;
+		namelen = MIN(strlen(sd->d_name), LX_NAMEMAX - 1);
+
+		ld->d_ino = sd->d_ino;
+		ld->d_off = sd->d_off;
+		ld->d_type = LX_DT_UNKNOWN;
+		(void) strncpy(ld->d_name, sd->d_name, namelen);
+		ld->d_name[namelen] = 0;
+		ld->d_reclen = (ushort_t)LX_RECLEN64(namelen);
+		/* Zero out any alignment padding */
+		bzero(ld->d_name + namelen, LX_ZEROLEN64(namelen));
+
+		if (is_sysfs) {
+			ld->d_type = lx_get_sysfs_dtype(ld->d_ino);
+		}
+
+		len -= sd->d_reclen;
+		size += ld->d_reclen;
+		sbuf += sd->d_reclen;
+		lbuf += ld->d_reclen;
+	}
+	return (size);
+}
+
+
+long
+lx_getdents64(int fd, caddr_t buf, size_t count)
+{
+	return (lx_getdents_common(fd, buf, count,
+	    sizeof (struct lx_dirent64), lx_getdents64_format));
+}