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tar: improve quality of diagnostics with incrementals

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Inspired by a prototype by Nathan Stratton Treadway in
<http://lists.gnu.org/archive/html/bug-tar/2013-01/msg00000.html>.
* src/incremen.c (read_num): Rewrite by merging read_negative_num
and read_unsigned_num.  Use strtosysint rather than rolling this
stuff ourselves.  Change return type to bool.  All uses changed.
(read_negative_num, read_unsigned_num): Remove.
(read_num, read_timespec, read_incr_db_2): Improve quality of
diagnostics, e.g., by supplying byte offset of error.
This commit is contained in:
Paul Eggert
2013-01-27 08:41:32 -08:00
parent 2f6c03cba2
commit 9cf743abf8
1 changed files with 90 additions and 105 deletions
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195
src/incremen.c
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@@ -1079,106 +1079,84 @@ read_obstack (FILE *fp, struct obstack *stk, size_t *pcount)
return c;
}
/* Read from file FP a nul-terminated string and convert it to
intmax_t. Return the resulting value in PVAL. Assume '-' has
already been read.
Throw a fatal error if the string cannot be converted or if the
converted value is less than MIN_VAL. */
static void
read_negative_num (FILE *fp, intmax_t min_val, intmax_t *pval)
{
int c;
size_t i;
char buf[INT_BUFSIZE_BOUND (intmax_t)];
char *ep;
buf[0] = '-';
for (i = 1; ISDIGIT (c = getc (fp)); i++)
{
if (i == sizeof buf - 1)
FATAL_ERROR ((0, 0, _("Field too long while reading snapshot file")));
buf[i] = c;
}
if (c < 0)
{
if (ferror (fp))
FATAL_ERROR ((0, errno, _("Read error in snapshot file")));
else
FATAL_ERROR ((0, 0, _("Unexpected EOF in snapshot file")));
}
buf[i] = 0;
errno = 0;
*pval = strtoimax (buf, &ep, 10);
if (c || errno || *pval < min_val)
FATAL_ERROR ((0, errno, _("Unexpected field value in snapshot file")));
}
/* Read from file FP a nul-terminated string and convert it to
uintmax_t. Return an intmax_t representation of the resulting
value in PVAL. Assume C has already been read.
Throw a fatal error if the string cannot be converted or if the
converted value exceeds MAX_VAL.
Return the last character read or EOF on end of file. */
static int
read_unsigned_num (int c, FILE *fp, uintmax_t max_val, intmax_t *pval)
{
size_t i;
uintmax_t u;
char buf[UINTMAX_STRSIZE_BOUND], *ep;
for (i = 0; ISDIGIT (c); i++)
{
if (i == sizeof buf - 1)
FATAL_ERROR ((0, 0, _("Field too long while reading snapshot file")));
buf[i] = c;
c = getc (fp);
}
if (c < 0)
{
if (ferror (fp))
FATAL_ERROR ((0, errno, _("Read error in snapshot file")));
else if (i == 0)
return c;
else
FATAL_ERROR ((0, 0, _("Unexpected EOF in snapshot file")));
}
buf[i] = 0;
errno = 0;
u = strtoumax (buf, &ep, 10);
if (c || errno || max_val < u)
FATAL_ERROR ((0, errno, _("Unexpected field value in snapshot file")));
*pval = represent_uintmax (u);
return c;
}
/* Read from file FP a nul-terminated string and convert it to
an integer in the range MIN_VAL..MAXVAL. Return the resulting
value, converted to intmax_t, in PVAL. MINVAL must be nonpositive.
/* Read from file FP a null-terminated string and convert it to an
integer. FIELDNAME is the intended use of the integer, useful for
diagnostics. MIN_VAL and MAX_VAL are its minimum and maximum
permissible values; MIN_VAL must be nonpositive and MAX_VAL positive.
Store into *PVAL the resulting value, converted to intmax_t.
Throw a fatal error if the string cannot be converted or if the
converted value is out of range.
Return the last character read or EOF on end of file. */
Return true if successful, false if end of file. */
static int
read_num (FILE *fp, intmax_t min_val, uintmax_t max_val, intmax_t *pval)
static bool
read_num (FILE *fp, char const *fieldname,
intmax_t min_val, uintmax_t max_val, intmax_t *pval)
{
int i;
char buf[INT_BUFSIZE_BOUND (intmax_t)];
char offbuf[INT_BUFSIZE_BOUND (off_t)];
char minbuf[INT_BUFSIZE_BOUND (intmax_t)];
char maxbuf[INT_BUFSIZE_BOUND (intmax_t)];
int conversion_errno;
int c = getc (fp);
if (c == '-')
bool negative = c == '-';
for (i = 0; (i == 0 && negative) || ISDIGIT (c); i++)
{
read_negative_num (fp, min_val, pval);
return 0;
buf[i] = c;
if (i == sizeof buf - 1)
FATAL_ERROR ((0, 0,
_("%s: byte %s: %s %.*s... too long"),
quotearg_colon (listed_incremental_option),
offtostr (ftello (fp), offbuf),
fieldname, i + 1, buf));
c = getc (fp);
}
return read_unsigned_num (c, fp, max_val, pval);
buf[i] = 0;
if (c < 0)
{
if (ferror (fp))
read_fatal (listed_incremental_option);
if (i != 0)
FATAL_ERROR ((0, 0, "%s: %s",
quotearg_colon (listed_incremental_option),
_("Unexpected EOF in snapshot file")));
return false;
}
if (c)
FATAL_ERROR ((0, 0,
_("%s: byte %s: %s %s followed by invalid byte 0x%02x"),
quotearg_colon (listed_incremental_option),
offtostr (ftello (fp), offbuf),
fieldname, buf, c));
*pval = strtosysint (buf, NULL, min_val, max_val);
conversion_errno = errno;
switch (conversion_errno)
{
case ERANGE:
FATAL_ERROR ((0, conversion_errno,
_("%s: byte %s: (valid range %s..%s)\n\t%s %s"),
quotearg_colon (listed_incremental_option),
offtostr (ftello (fp), offbuf),
imaxtostr (min_val, minbuf),
umaxtostr (max_val, maxbuf), fieldname, buf));
default:
FATAL_ERROR ((0, conversion_errno,
_("%s: byte %s: %s %s"),
quotearg_colon (listed_incremental_option),
offtostr (ftello (fp), offbuf), fieldname, buf));
case 0:
break;
}
return true;
}
/* Read from FP two NUL-terminated strings representing a struct
@@ -1189,15 +1167,20 @@ read_num (FILE *fp, intmax_t min_val, uintmax_t max_val, intmax_t *pval)
static void
read_timespec (FILE *fp, struct timespec *pval)
{
intmax_t i;
int c = read_num (fp, TYPE_MINIMUM (time_t), TYPE_MAXIMUM (time_t), &i);
pval->tv_sec = i;
intmax_t s, ns;
if (c || read_num (fp, 0, BILLION - 1, &i))
FATAL_ERROR ((0, 0, "%s: %s",
quotearg_colon (listed_incremental_option),
_("Unexpected EOF in snapshot file")));
pval->tv_nsec = i;
if (read_num (fp, "sec", TYPE_MINIMUM (time_t), TYPE_MAXIMUM (time_t), &s)
&& read_num (fp, "nsec", 0, BILLION - 1, &ns))
{
pval->tv_sec = s;
pval->tv_nsec = ns;
}
else
{
FATAL_ERROR ((0, 0, "%s: %s",
quotearg_colon (listed_incremental_option),
_("Unexpected EOF in snapshot file")));
}
}
/* Read incremental snapshot format 2 */
@@ -1205,6 +1188,7 @@ static void
read_incr_db_2 (void)
{
struct obstack stk;
char offbuf[INT_BUFSIZE_BOUND (off_t)];
obstack_init (&stk);
@@ -1221,20 +1205,20 @@ read_incr_db_2 (void)
char *content;
size_t s;
if (read_num (listed_incremental_stream, 0, 1, &i))
if (! read_num (listed_incremental_stream, "nfs", 0, 1, &i))
return; /* Normal return */
nfs = i;
read_timespec (listed_incremental_stream, &mtime);
if (read_num (listed_incremental_stream,
TYPE_MINIMUM (dev_t), TYPE_MAXIMUM (dev_t), &i))
if (! read_num (listed_incremental_stream, "dev",
TYPE_MINIMUM (dev_t), TYPE_MAXIMUM (dev_t), &i))
break;
dev = i;
if (read_num (listed_incremental_stream,
TYPE_MINIMUM (ino_t), TYPE_MAXIMUM (ino_t), &i))
if (! read_num (listed_incremental_stream, "ino",
TYPE_MINIMUM (ino_t), TYPE_MAXIMUM (ino_t), &i))
break;
ino = i;
@@ -1246,8 +1230,9 @@ read_incr_db_2 (void)
while (read_obstack (listed_incremental_stream, &stk, &s) == 0 && s > 1)
;
if (getc (listed_incremental_stream) != 0)
FATAL_ERROR ((0, 0, "%s: %s",
FATAL_ERROR ((0, 0, _("%s: byte %s: %s"),
quotearg_colon (listed_incremental_option),
offtostr (ftello (listed_incremental_stream), offbuf),
_("Missing record terminator")));
content = obstack_finish (&stk);