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#include "fdiskP.h"
#include "pathnames.h"
#include "canonicalize.h"
#include <ctype.h>
/**
* SECTION: utils
* @title: Utils
* @short_description: misc fdisk functions
*/
static int read_from_device(struct fdisk_context *cxt,
unsigned char *buf,
uintmax_t start, size_t size)
{
ssize_t r;
assert(cxt);
DBG(CXT, ul_debugobj(cxt, "reading: offset=%ju, size=%zu",
start, size));
r = lseek(cxt->dev_fd, start, SEEK_SET);
if (r == -1)
{
DBG(CXT, ul_debugobj(cxt, "failed to seek to offset %ju: %m", start));
return -errno;
}
errno = 0;
r = read(cxt->dev_fd, buf, size);
if (r < 0 || (size_t)r != size) {
if (!errno)
errno = EINVAL; /* probably too small file/device */
DBG(CXT, ul_debugobj(cxt, "failed to read %zu from offset %ju: %m",
size, start));
return -errno;
}
return 0;
}
/*
* Zeros in-memory first sector buffer
*/
int fdisk_init_firstsector_buffer(struct fdisk_context *cxt,
unsigned int protect_off,
unsigned int protect_size)
{
if (!cxt)
return -EINVAL;
assert(protect_off + protect_size <= cxt->sector_size);
if (!cxt->firstsector || cxt->firstsector_bufsz != cxt->sector_size) {
/* Let's allocate a new buffer if no allocated yet, or the
* current buffer has incorrect size */
if (!cxt->parent || cxt->parent->firstsector != cxt->firstsector)
free(cxt->firstsector);
DBG(CXT, ul_debugobj(cxt, "initialize in-memory first sector "
"buffer [sector_size=%lu]", cxt->sector_size));
cxt->firstsector = calloc(1, cxt->sector_size);
if (!cxt->firstsector)
return -ENOMEM;
cxt->firstsector_bufsz = cxt->sector_size;
return 0;
}
DBG(CXT, ul_debugobj(cxt, "zeroize in-memory first sector buffer"));
memset(cxt->firstsector, 0, cxt->firstsector_bufsz);
if (protect_size) {
/*
* It would be possible to reuse data from cxt->firstsector
* (call memset() for non-protected area only) and avoid one
* read() from the device, but it seems like a too fragile
* solution as we have no clue about stuff in the buffer --
* maybe it was already modified. Let's re-read from the device
* to be sure. -- kzak 13-Apr-2015
*/
DBG(CXT, ul_debugobj(cxt, "first sector protection enabled -- re-reading"));
read_from_device(cxt, cxt->firstsector, protect_off, protect_size);
}
return 0;
}
int fdisk_read_firstsector(struct fdisk_context *cxt)
{
int rc;
assert(cxt);
assert(cxt->sector_size);
rc = fdisk_init_firstsector_buffer(cxt, 0, 0);
if (rc)
return rc;
assert(cxt->sector_size == cxt->firstsector_bufsz);
return read_from_device(cxt, cxt->firstsector, 0, cxt->sector_size);
}
/**
* fdisk_partname:
* @dev: device name
* @partno: partition name
*
* Return: allocated buffer with partition name, use free() to deallocate.
*/
char *fdisk_partname(const char *dev, size_t partno)
{
char *res = NULL;
const char *p = "";
char *dev_mapped = NULL;
int w = 0;
if (!dev || !*dev) {
if (asprintf(&res, "%zd", partno) > 0)
return res;
return NULL;
}
/* It is impossible to predict /dev/dm-N partition names. */
if (strncmp(dev, "/dev/dm-", sizeof("/dev/dm-") - 1) == 0) {
dev_mapped = canonicalize_dm_name (dev + 5);
if (dev_mapped)
dev = dev_mapped;
}
w = strlen(dev);
if (isdigit(dev[w - 1]))
#ifdef __GNU__
p = "s";
#else
p = "p";
#endif
/* devfs kludge - note: fdisk partition names are not supposed
to equal kernel names, so there is no reason to do this */
if (endswith(dev, "disc")) {
w -= 4;
p = "part";
}
/* udev names partitions by appending -partN
e.g. ata-SAMSUNG_SV8004H_0357J1FT712448-part1
multipath-tools kpartx.rules also append -partN */
if ((strncmp(dev, _PATH_DEV_BYID, sizeof(_PATH_DEV_BYID) - 1) == 0) ||
strncmp(dev, _PATH_DEV_BYPATH, sizeof(_PATH_DEV_BYPATH) - 1) == 0 ||
strncmp(dev, "/dev/mapper", sizeof("/dev/mapper") - 1) == 0) {
/* check for <name><partno>, e.g. mpatha1 */
if (asprintf(&res, "%.*s%zu", w, dev, partno) <= 0)
res = NULL;
if (res && access(res, F_OK) == 0)
goto done;
free(res);
/* check for partition separator "p" */
if (asprintf(&res, "%.*sp%zu", w, dev, partno) <= 0)
res = NULL;
if (res && access(res, F_OK) == 0)
goto done;
free(res);
/* otherwise, default to "-path" */
p = "-part";
}
if (asprintf(&res, "%.*s%s%zu", w, dev, p, partno) <= 0)
res = NULL;
done:
free(dev_mapped);
return res;
}
#ifdef TEST_PROGRAM
struct fdisk_label *fdisk_new_dos_label(struct fdisk_context *cxt) { return NULL; }
struct fdisk_label *fdisk_new_bsd_label(struct fdisk_context *cxt) { return NULL; }
static int test_partnames(struct fdisk_test *ts, int argc, char *argv[])
{
size_t i;
const char *disk = argv[1];
for (i = 0; i < 5; i++) {
char *p = fdisk_partname(disk, i + 1);
if (p)
printf("%zu: '%s'\n", i + 1, p);
free(p);
}
return 0;
}
int main(int argc, char *argv[])
{
struct fdisk_test tss[] = {
{ "--partnames", test_partnames, "<diskname>" },
{ NULL }
};
return fdisk_run_test(tss, argc, argv);
}
#endif
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