#include <errno.h>
#include <fcntl.h>
#include <arpa/inet.h>
+#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/ioctl.h>
#endif
+#ifdef HAVE_TM_TM_GMTOFF
+#include <time.h>
+#endif
+
#include "bupsplit.h"
#if defined(FS_IOC_GETFLAGS) && defined(FS_IOC_SETFLAGS)
#define FS_NOCOW_FL 0
#endif
+
+typedef unsigned char byte;
+
static int istty2 = 0;
#endif // not __WIN32__ or __CYGWIN__
-static unsigned long long count_leading_zeros(const unsigned char * const buf,
- unsigned long long len)
-{
- const unsigned char *cur = buf;
- while(len-- && *cur == 0)
- cur++;
- return cur - buf;
-}
-
-
static int write_all(int fd, const void *buf, const size_t count)
{
size_t written = 0;
}
+static PyObject *append_sparse_region(const int fd, unsigned long long n)
+{
+ while (n)
+ {
+ off_t new_off;
+ if (!INTEGRAL_ASSIGNMENT_FITS(&new_off, n))
+ new_off = INT_MAX;
+ const off_t off = lseek(fd, new_off, SEEK_CUR);
+ if (off == (off_t) -1)
+ return PyErr_SetFromErrno(PyExc_IOError);
+ n -= new_off;
+ }
+ return NULL;
+}
+
+
+static PyObject *record_sparse_zeros(unsigned long long *new_pending,
+ const int fd,
+ unsigned long long prev_pending,
+ const unsigned long long count)
+{
+ // Add count additional sparse zeros to prev_pending and store the
+ // result in new_pending, or if the total won't fit in
+ // new_pending, write some of the zeros to fd sparsely, and store
+ // the remaining sum in new_pending.
+ if (!uadd(new_pending, prev_pending, count))
+ {
+ PyObject *err = append_sparse_region(fd, prev_pending);
+ if (err != NULL)
+ return err;
+ *new_pending = count;
+ }
+ return NULL;
+}
+
+
+static const byte * find_not_zero(const byte * const start,
+ const byte * const end)
+{
+ // Return a pointer to first non-zero byte between start and end,
+ // or end if there isn't one.
+ assert(start <= end);
+ const unsigned char *cur = start;
+ while (cur < end && *cur == 0)
+ cur++;
+ return cur;
+}
+
+
+static const byte * const find_trailing_zeros(const byte * const start,
+ const byte * const end)
+{
+ // Return a pointer to the start of any trailing run of zeros, or
+ // end if there isn't one.
+ assert(start <= end);
+ if (start == end)
+ return end;
+ const byte * cur = end;
+ while (cur > start && *--cur == 0) {}
+ if (*cur == 0)
+ return cur;
+ else
+ return cur + 1;
+}
+
+
+static const byte *find_non_sparse_end(const byte * const start,
+ const byte * const end,
+ const unsigned long long min_len)
+{
+ // Return the first pointer to a min_len sparse block in [start,
+ // end) if there is one, otherwise a pointer to the start of any
+ // trailing run of zeros. If there are no trailing zeros, return
+ // end.
+ if (start == end)
+ return end;
+ assert(start < end);
+ assert(min_len);
+ // Probe in min_len jumps, searching backward from the jump
+ // destination for a non-zero byte. If such a byte is found, move
+ // just past it and try again.
+ const byte *candidate = start;
+ // End of any run of zeros, starting at candidate, that we've already seen
+ const byte *end_of_known_zeros = candidate;
+ while (end - candidate >= min_len) // Handle all min_len candidate blocks
+ {
+ const byte * const probe_end = candidate + min_len;
+ const byte * const trailing_zeros =
+ find_trailing_zeros(end_of_known_zeros, probe_end);
+ if (trailing_zeros == probe_end)
+ end_of_known_zeros = candidate = probe_end;
+ else if (trailing_zeros == end_of_known_zeros)
+ {
+ assert(candidate >= start);
+ assert(candidate <= end);
+ assert(*candidate == 0);
+ return candidate;
+ }
+ else
+ {
+ candidate = trailing_zeros;
+ end_of_known_zeros = probe_end;
+ }
+ }
+
+ if (candidate == end)
+ return end;
+
+ // No min_len sparse run found, search backward from end
+ const byte * const trailing_zeros = find_trailing_zeros(end_of_known_zeros,
+ end);
+
+ if (trailing_zeros == end_of_known_zeros)
+ {
+ assert(candidate >= start);
+ assert(candidate < end);
+ assert(*candidate == 0);
+ assert(end - candidate < min_len);
+ return candidate;
+ }
+
+ if (trailing_zeros == end)
+ {
+ assert(*(end - 1) != 0);
+ return end;
+ }
+
+ assert(end - trailing_zeros < min_len);
+ assert(trailing_zeros >= start);
+ assert(trailing_zeros < end);
+ assert(*trailing_zeros == 0);
+ return trailing_zeros;
+}
+
+
static PyObject *bup_write_sparsely(PyObject *self, PyObject *args)
{
int fd;
if (!INTEGRAL_ASSIGNMENT_FITS(&buf_len, sbuf_len))
return PyErr_Format(PyExc_OverflowError, "buffer length too large");
- // For now, there are some cases where we just give up if the
- // values are too large, but we could try to break up the relevant
- // operations into chunks.
-
- // Deal with preceding zeros. Just make them sparse, along with
- // any leading zeros in buf, even if the region's not >= min,
- // since the alternative is a potentially extra small write.
- if (prev_sparse_len)
+ const byte * block = buf; // Start of pending block
+ const byte * const end = buf + buf_len;
+ unsigned long long zeros = prev_sparse_len;
+ while (1)
{
- const unsigned long long zeros = count_leading_zeros(buf, buf_len);
- unsigned long long new_sparse_len = 0;
- if (!uadd(&new_sparse_len, prev_sparse_len, zeros))
- return PyErr_Format (PyExc_OverflowError, "sparse region too large");
- if (zeros == buf_len)
- return PyLong_FromUnsignedLongLong(new_sparse_len);
-
- off_t new_off;
- if (!INTEGRAL_ASSIGNMENT_FITS(&new_off, new_sparse_len))
- return PyErr_Format(PyExc_OverflowError,
- "sparse region too large for seek");
- const off_t off = lseek(fd, new_off, SEEK_CUR);
- if (off == -1)
- return PyErr_SetFromErrno(PyExc_IOError);
- buf += zeros;
- buf_len -= zeros;
- }
+ assert(block <= end);
+ if (block == end)
+ return PyLong_FromUnsignedLongLong(zeros);
- int rc;
- unsigned long long unexamined = buf_len;
- unsigned char *block_start = buf, *cur = buf;
- while(unexamined)
- {
- const unsigned long long zeros = count_leading_zeros(cur, unexamined);
- assert(zeros <= unexamined);
- unexamined -= zeros;
- if (unexamined == 0) // Runs off the end.
+ if (*block != 0)
{
- rc = write_all(fd, block_start, cur - block_start);
+ // Look for the end of block, i.e. the next sparse run of
+ // at least min_sparse_len zeros, or the end of the
+ // buffer.
+ const byte * const probe = find_non_sparse_end(block + 1, end,
+ min_sparse_len);
+ // Either at end of block, or end of non-sparse; write pending data
+ PyObject *err = append_sparse_region(fd, zeros);
+ if (err != NULL)
+ return err;
+ int rc = write_all(fd, block, probe - block);
if (rc)
return PyErr_SetFromErrno(PyExc_IOError);
- return PyLong_FromUnsignedLongLong(zeros);
- }
- cur += zeros;
- if (zeros >= min_sparse_len)
- {
- off_t new_off;
- if (!INTEGRAL_ASSIGNMENT_FITS(&new_off, zeros))
- return PyErr_Format(PyExc_ValueError,
- "zero count overflows off_t");
- off_t off = lseek(fd, new_off, SEEK_CUR);
- if (off == -1)
- return PyErr_SetFromErrno(PyExc_IOError);
- block_start = cur;
+
+ if (end - probe < min_sparse_len)
+ zeros = end - probe;
+ else
+ zeros = min_sparse_len;
+ block = probe + zeros;
}
- while (unexamined && *cur != 0)
+ else // *block == 0
{
- cur++; unexamined--;
+ // Should be in the first loop iteration, a sparse run of
+ // zeros, or nearly at the end of the block (within
+ // min_sparse_len).
+ const byte * const zeros_end = find_not_zero(block, end);
+ PyObject *err = record_sparse_zeros(&zeros, fd,
+ zeros, zeros_end - block);
+ if (err != NULL)
+ return err;
+ assert(block <= zeros_end);
+ block = zeros_end;
}
}
- rc = write_all(fd, block_start, cur - block_start);
- if (rc)
- return PyErr_SetFromErrno(PyExc_IOError);
- return PyInt_FromLong(0);
}
}
+#ifdef HAVE_TM_TM_GMTOFF
+static PyObject *bup_localtime(PyObject *self, PyObject *args)
+{
+ long long lltime;
+ time_t ttime;
+ if (!PyArg_ParseTuple(args, "L", &lltime))
+ return NULL;
+ if (!INTEGRAL_ASSIGNMENT_FITS(&ttime, lltime))
+ return PyErr_Format(PyExc_OverflowError, "time value too large");
+
+ struct tm tm;
+ if(localtime_r(&ttime, &tm) == NULL)
+ return PyErr_SetFromErrno(PyExc_OSError);
+
+ // Match the Python struct_time values.
+ return Py_BuildValue("[i,i,i,i,i,i,i,i,i,i,s]",
+ 1900 + tm.tm_year, tm.tm_mon + 1, tm.tm_mday,
+ tm.tm_hour, tm.tm_min, tm.tm_sec,
+ tm.tm_wday, tm.tm_yday + 1,
+ tm.tm_isdst, tm.tm_gmtoff, tm.tm_zone);
+}
+#endif /* def HAVE_TM_TM_GMTOFF */
+
+
static PyMethodDef helper_methods[] = {
{ "write_sparsely", bup_write_sparsely, METH_VARARGS,
"Write buf excepting zeros at the end. Return trailing zero count." },
"Extended version of lstat." },
{ "fstat", bup_fstat, METH_VARARGS,
"Extended version of fstat." },
+#ifdef HAVE_TM_TM_GMTOFF
+ { "localtime", bup_localtime, METH_VARARGS,
+ "Return struct_time elements plus the timezone offset and name." },
+#endif
{ NULL, NULL, 0, NULL }, // sentinel
};
assert(sizeof(PY_LONG_LONG) <= sizeof(long long));
assert(sizeof(unsigned PY_LONG_LONG) <= sizeof(unsigned long long));
+ // Originally required by append_sparse_region()
+ {
+ off_t probe;
+ if (!INTEGRAL_ASSIGNMENT_FITS(&probe, INT_MAX))
+ {
+ fprintf(stderr, "off_t can't hold INT_MAX; please report.\n");
+ exit(1);
+ }
+ }
+
char *e;
PyObject *m = Py_InitModule("_helpers", helper_methods);
if (m == NULL)
projects / bup.git / blobdiff