Add splitfs vfs layer into libstand, which allows loading big kernels and

modules split across several physical medias. Following is how it works:

The splitfs code, when asked to open "foo" looks for a file "foo.split"
which is a text file containing a list of filenames and media names, e.g.

	foo.aa "Kernel floppy 1"
	foo.ab "Kernel floppy 2"
	foo.ac "Kernel and modules floppy"

For each file segment, the process is:

- try to open the file
- prompt "Insert the disk labelled <whatever> and press any key..."
- try to open the file
- return error if file could not be located

RE team is free to use this feature in the upcoming 5.0-DP1.

Reviewed by:	msmith, dcs

6 files changed, 292 insertions, 3 deletions

diff --git a/lib/libstand/Makefile b/lib/libstand/Makefile
index 3349522..08f7319 100644
--- a/lib/libstand/Makefile
+++ b/lib/libstand/Makefile
@@ -153,6 +153,7 @@ SRCS+=	bootp.c rarp.c bootparam.c
 SRCS+=	ufs.c nfs.c cd9660.c tftp.c zipfs.c bzipfs.c
 SRCS+=	netif.c nfs.c
 SRCS+=	dosfs.c ext2fs.c
+SRCS+=	splitfs.c
 
 beforeinstall:
 	${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m 444 ${.CURDIR}/stand.h \
diff --git a/lib/libstand/bzipfs.c b/lib/libstand/bzipfs.c
index 5dd6fab..c0a8d9b 100644
--- a/lib/libstand/bzipfs.c
+++ b/lib/libstand/bzipfs.c
@@ -150,7 +150,7 @@ bzf_open(const char *fname, struct open_file *f)
 
     /* If the name already ends in .gz or .bz2, ignore it */
     if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
-	    || !strcmp(cp, ".bz2")))
+	    || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
 	return(ENOENT);
 
     /* Construct new name */
diff --git a/lib/libstand/gzipfs.c b/lib/libstand/gzipfs.c
index 59034ff..00c8f8f 100644
--- a/lib/libstand/gzipfs.c
+++ b/lib/libstand/gzipfs.c
@@ -175,7 +175,7 @@ zf_open(const char *fname, struct open_file *f)
 
     /* If the name already ends in .gz or .bz2, ignore it */
     if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
-	    || !strcmp(cp, ".bz2")))
+	    || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
 	return(ENOENT);
 
     /* Construct new name */
diff --git a/lib/libstand/splitfs.c b/lib/libstand/splitfs.c
new file mode 100644
index 0000000..26c7d1f
--- /dev/null
+++ b/lib/libstand/splitfs.c
@@ -0,0 +1,287 @@
+/* 
+ * Copyright (c) 2002 Maxim Sobolev
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "stand.h"
+
+#define NTRIES		(3)
+#define CONF_BUF	(512)
+#define SEEK_BUF	(512)
+
+struct split_file
+{
+    char  **filesv;	/* Filenames */
+    char  **descsv;	/* Descriptions */
+    int	  filesc;	/* Number of parts */
+    int	  curfile;	/* Current file number */
+    int	  curfd;	/* Current file descriptor */
+    off_t tot_pos;	/* Offset from the beginning of the sequence */
+    off_t file_pos;	/* Offset from the beginning of the slice */
+};
+
+static int	splitfs_open(const char *path, struct open_file *f);
+static int	splitfs_close(struct open_file *f);
+static int	splitfs_read(struct open_file *f, void *buf, size_t size, size_t *resid);
+static off_t	splitfs_seek(struct open_file *f, off_t offset, int where);
+static int	splitfs_stat(struct open_file *f, struct stat *sb);
+
+struct fs_ops splitfs_fsops = {
+    "split",
+    splitfs_open, 
+    splitfs_close, 
+    splitfs_read,
+    null_write,
+    splitfs_seek,
+    splitfs_stat,
+    null_readdir
+};
+
+static void
+split_file_destroy(struct split_file *sf)
+{
+     int i;
+
+     if (sf->filesc > 0) {
+	for (i = 0; i < sf->filesc; i++) {
+	    free(sf->filesv[i]);
+	    free(sf->descsv[i]);
+	}
+	free(sf->filesv);
+	free(sf->descsv);
+     }
+     free(sf);
+}
+
+static int
+splitfs_open(const char *fname, struct open_file *f)
+{
+    char *buf, *confname, *cp;
+    int	conffd;
+    struct split_file *sf;
+    struct stat sb;
+
+    printf("%s\n", fname);
+    /* Have to be in "just read it" mode */
+    if (f->f_flags != F_READ)
+	return(EPERM);
+
+    /* If the name already ends in `.split', ignore it */
+    if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".split")))
+	return(ENOENT);
+
+    /* Construct new name */
+    confname = malloc(strlen(fname) + 7);
+    sprintf(confname, "%s.split", fname);
+
+    /* Try to open the configuration file */
+    conffd = open(confname, O_RDONLY);
+    free(confname);
+    if (conffd == -1)
+	return(ENOENT);
+
+    if (fstat(conffd, &sb) < 0) {
+	printf("splitfs_open: stat failed\n");
+	close(conffd);
+	return(ENOENT);
+    }
+    if (!S_ISREG(sb.st_mode)) {
+	printf("splitfs_open: not a file\n");
+	close(conffd);
+	return(EISDIR);			/* best guess */
+    }
+
+    /* Allocate a split_file structure, populate it from the config file */
+    sf = malloc(sizeof(struct split_file));
+    bzero(sf, sizeof(struct split_file));
+    buf = malloc(CONF_BUF);
+    while (fgetstr(buf, CONF_BUF, conffd) > 0) {
+	cp = buf;
+	while ((*cp != '\0') && (isspace(*cp) == 0))
+	    cp++;
+	if (*cp != '\0') {
+	    *cp = '\0';
+	    cp++;
+	}
+	while ((*cp != '\0') && (isspace(*cp) != 0))
+	    cp++;
+	if (*cp == '\0')
+	    cp = buf;
+	sf->filesc++;
+	sf->filesv = realloc(sf->filesv, sizeof(*(sf->filesv)) * sf->filesc);
+	sf->descsv = realloc(sf->descsv, sizeof(*(sf->descsv)) * sf->filesc);
+	sf->filesv[sf->filesc - 1] = strdup(buf);
+	sf->descsv[sf->filesc - 1] = strdup(cp);
+    }
+    free(buf);
+    close(conffd);
+
+    if ((sf->filesc == 0) || ((sf->curfd = open(sf->filesv[0], O_RDONLY)) == -1)) {
+	split_file_destroy(sf);
+	return(ENOENT);
+    }
+
+    /* Looks OK, we'll take it */
+    f->f_fsdata = sf;
+    return (0);
+}
+
+static int
+splitfs_close(struct open_file *f)
+{
+    int fd;
+    struct split_file *sf;
+
+    sf = (struct split_file *)f->f_fsdata;
+    fd = sf->curfd;
+    split_file_destroy(sf);
+    return(close(fd));
+}
+ 
+static int 
+splitfs_read(struct open_file *f, void *buf, size_t size, size_t *resid)
+{
+    int i, nread, totread;
+    struct split_file *sf;
+
+    sf = (struct split_file *)f->f_fsdata;
+    totread = 0;
+    do {
+	nread = read(sf->curfd, buf, size - totread);
+
+	/* Error? */
+	if (nread == -1)
+	    return (errno);
+
+	sf->tot_pos += nread;
+	sf->file_pos += nread;
+	totread += nread;
+	buf += nread;
+
+	if (totread < size) {				/* EOF */
+	    if (sf->curfile == (sf->filesc - 1))	/* Last slice */
+		break;
+
+	    /* Close previous slice */
+	    if (close(sf->curfd) != 0)
+		return (errno);
+
+	    sf->curfile++;
+	    for (i = 0;; i++) {
+		sf->curfd = open(sf->filesv[sf->curfile], O_RDONLY);
+		if (sf->curfd >= 0)
+		    break;
+		if ((sf->curfd == -1) && (errno != ENOENT))
+		    return (errno);
+		if (i == NTRIES)
+		    return (EIO);
+		printf("\nInsert disk labelled %s and press any key...", sf->descsv[sf->curfile]);
+		getchar();putchar('\n');
+	    }
+	    sf->file_pos = 0;
+	}
+    } while (totread < size);
+
+    if (resid != NULL)
+	*resid = size - totread;
+
+    return (0);
+}
+
+static off_t
+splitfs_seek(struct open_file *f, off_t offset, int where)
+{
+    int nread;
+    size_t resid;
+    off_t new_pos, seek_by;
+    struct split_file *sf;
+
+    sf = (struct split_file *)f->f_fsdata;
+
+    seek_by = offset;
+    switch (where) {
+    case SEEK_SET:
+	seek_by -= sf->tot_pos;
+	break;
+    case SEEK_CUR:
+	break;
+    case SEEK_END:
+	panic("splitfs_seek: SEEK_END not supported");
+	break;
+    }
+
+    if (seek_by > 0) {
+	/*
+	 * Seek forward - implemented using splitfs_read(), because otherwise we'll be
+	 * unable to detect that we have crossed slice boundary and hence
+	 * unable to do a long seek crossing that boundary.
+	 */
+	void *tmp;
+
+	tmp = malloc(SEEK_BUF);
+	if (tmp == NULL)
+	    return (-1);
+
+	nread = 0;
+	for (; seek_by > 0; seek_by -= nread) {
+	    resid = 0;
+	    errno = splitfs_read(f, tmp, min(seek_by, SEEK_BUF), &resid);
+	    nread = min(seek_by, SEEK_BUF) - resid;
+	    if ((errno != 0) || (nread == 0))
+		/* Error or EOF */
+		break;
+	}
+	free(tmp);
+	if (errno != 0)
+	    return (-1);
+    }
+
+    if (seek_by != 0) {
+	/* Seek backward or seek past the boundary of the last slice */
+	if (sf->file_pos + seek_by < 0)
+	    panic("splitfs_seek: can't seek past the beginning of the slice");
+	new_pos = lseek(sf->curfd, seek_by, SEEK_CUR);
+	if (new_pos < 0)
+	    return (-1);
+	sf->tot_pos += new_pos - sf->file_pos;
+	sf->file_pos = new_pos;
+    }
+
+    return (sf->tot_pos);
+}
+
+static int
+splitfs_stat(struct open_file *f, struct stat *sb)
+{
+    int	result;
+    struct split_file *sf = (struct split_file *)f->f_fsdata;
+
+    /* stat as normal, but indicate that size is unknown */
+    if ((result = fstat(sf->curfd, sb)) == 0)
+	sb->st_size = -1;
+    return (result);
+}
diff --git a/lib/libstand/stand.h b/lib/libstand/stand.h
index fcbb2e8..c4b1fae 100644
--- a/lib/libstand/stand.h
+++ b/lib/libstand/stand.h
@@ -125,6 +125,7 @@ extern struct fs_ops zipfs_fsops;
 extern struct fs_ops bzipfs_fsops;
 extern struct fs_ops dosfs_fsops;
 extern struct fs_ops ext2fs_fsops;
+extern struct fs_ops splitfs_fsops;
 
 /* where values for lseek(2) */
 #define	SEEK_SET	0	/* set file offset to offset */
diff --git a/lib/libstand/zipfs.c b/lib/libstand/zipfs.c
index 59034ff..00c8f8f 100644
--- a/lib/libstand/zipfs.c
+++ b/lib/libstand/zipfs.c
@@ -175,7 +175,7 @@ zf_open(const char *fname, struct open_file *f)
 
     /* If the name already ends in .gz or .bz2, ignore it */
     if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
-	    || !strcmp(cp, ".bz2")))
+	    || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
 	return(ENOENT);
 
     /* Construct new name */