diff options
author | sobomax <sobomax@FreeBSD.org> | 2002-03-17 12:18:05 +0000 |
---|---|---|
committer | sobomax <sobomax@FreeBSD.org> | 2002-03-17 12:18:05 +0000 |
commit | 9d703dcfedc6263b12ba725785b027e958c540f3 (patch) | |
tree | dd2d29323555872217afb04ebb572acebac59fcd /lib/libstand/splitfs.c | |
parent | 006a375bc447bfc5b3db07294bf35dbe748b38a9 (diff) | |
download | FreeBSD-src-9d703dcfedc6263b12ba725785b027e958c540f3.zip FreeBSD-src-9d703dcfedc6263b12ba725785b027e958c540f3.tar.gz |
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
Diffstat (limited to 'lib/libstand/splitfs.c')
-rw-r--r-- | lib/libstand/splitfs.c | 287 |
1 files changed, 287 insertions, 0 deletions
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); +} |