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SDB - Self-describing Bus
Commit 7acbfd79 authored by Alessandro Rubini's avatar Alessandro Rubini
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sdbfs/userspace: sdb-read does fseek/read if mmap fails 

Signed-off-by: Alessandro Rubini's avatarAlessandro Rubini <rubini@gnudd.com>
parent 68712eec
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Showing with 31 additions and 15 deletions
sdbfs/userspace/sdb-read.c
View file @ 7acbfd79
/*
* Copyright (C) 2012 CERN (www.cern.ch)
* Copyright (C) 2012,2014 CERN (www.cern.ch)
* Author: Alessandro Rubini <rubini@gnudd.com>
*
* Released according to the GNU GPL, version 2 or any later version.
......@@ -24,17 +24,31 @@ char *prgname;
int opt_long, opt_verbose, opt_read, opt_entry;
struct sdbr_drvdata {
void *mapaddr;
FILE *f;
};
/*
* This read method is not really needed, but it's there
* to exercise the library procedures
* This read method is needed for non-mmappable files, or stuff that
* you can't know the size of (e.g., char devices). You can force use of
* read, to exercise the library procedures, using "-r"
*/
static int do_read(struct sdbfs *fs, int offset, void *buf, int count)
{
struct sdbr_drvdata *drvdata = fs->drvdata;
if (opt_verbose)
fprintf(stderr, "%s @ 0x%08x - size 0x%x (%i)\n", __func__,
offset, count, count);
memcpy(buf, fs->drvdata + offset, count);
return count;
if (drvdata->mapaddr) {
memcpy(buf, drvdata->mapaddr + offset, count);
return count;
}
/* not mmapped: seek and read */
if (fseek(drvdata->f, offset, SEEK_SET) < 0)
return -1;
return fread(buf, 1, count, drvdata->f);
}
/* Boring ascii representation of a device */
......@@ -119,6 +133,7 @@ int main(int argc, char **argv)
struct sdbfs _fs;
struct sdbfs *fs = &_fs; /* I like to type "fs->" */
struct stat stbuf;
struct sdbr_drvdata *drvdata;
void *mapaddr;
char *fsname;
char *filearg = NULL;
......@@ -162,27 +177,28 @@ int main(int argc, char **argv)
exit(1);
}
/* Save the file pointer in drvdata for fseek/fread use */
drvdata = calloc(1, sizeof(*drvdata));
drvdata->f = f;
stbuf.st_size += pagesize - 1;
stbuf.st_size &= ~(pagesize - 1);
mapaddr = mmap(0, stbuf.st_size, PROT_READ, MAP_PRIVATE, fileno(f), 0);
if (mapaddr == MAP_FAILED) {
fprintf(stderr, "%s: mmap(%s): %s\n", prgname, fsname,
strerror(errno));
exit(1);
}
if (mapaddr == MAP_FAILED)
drvdata->mapaddr = NULL;
else
drvdata->mapaddr = mapaddr;
/* So, describe the filesystem instance and give it to the library */
memset(fs, 0, sizeof(*fs));
fs->drvdata = drvdata;
fs->name = fsname; /* not mandatory */
fs->blocksize = 256; /* only used for writing, actually */
fs->entrypoint = opt_entry;
if (opt_read) {
fs->drvdata = mapaddr;
if (opt_read || !drvdata->mapaddr)
fs->read = do_read;
} else {
else
fs->data = mapaddr;
}
err = sdbfs_dev_create(fs, opt_verbose);
if (err) {
......
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