* [PATCH v3] btrfs-progs: Improve the parse_size() error message.
@ 2014-06-13 2:55 Qu Wenruo
2014-06-18 15:52 ` David Sterba
0 siblings, 1 reply; 2+ messages in thread
From: Qu Wenruo @ 2014-06-13 2:55 UTC (permalink / raw)
To: linux-btrfs; +Cc: dsterba
When using parse_size(), even non-numeric value is passed, it will only
give error message "ERROR: size value is empty", which is quite
confusing for end users.
This patch will introduce more meaningful error message for the
following new cases
1) Invalid size string (non-numeric string)
2) Minus size value (like "-1K")
Also this patch will take full use of endptr returned by strtoll() to
reduce unneeded loop.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
changlog:
v2:
Remove uneeded return value
Avoid abuse of goto
v3:
Don't reparse size twice
Better u64 overflow check
---
utils.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 50 insertions(+), 16 deletions(-)
diff --git a/utils.c b/utils.c
index 392c5cf..eab3a1b 100644
--- a/utils.c
+++ b/utils.c
@@ -1610,20 +1610,53 @@ scan_again:
return 0;
}
-u64 parse_size(char *s)
+/* A not-so-good version fls64. No fascinating optimization since
+ * no one except parse_size use it */
+static int fls64(u64 x)
{
int i;
+
+ for (i = 0; i <64; i++)
+ if (x << i & (1UL << 63))
+ return 64 - i;
+ return 64 - i;
+}
+
+u64 parse_size(char *s)
+{
char c;
+ char *endptr;
u64 mult = 1;
+ u64 ret;
- for (i = 0; s && s[i] && isdigit(s[i]); i++) ;
- if (!i) {
- fprintf(stderr, "ERROR: size value is empty\n");
- exit(50);
+ if (!s) {
+ fprintf(stderr, "ERROR: Size value is empty\n");
+ exit(1);
}
-
- if (s[i]) {
- c = tolower(s[i]);
+ if (s[0] == '-') {
+ fprintf(stderr,
+ "ERROR: Size value '%s' is less equal than 0\n", s);
+ exit(1);
+ }
+ ret = strtoull(s, &endptr, 10);
+ if (endptr == s) {
+ fprintf(stderr, "ERROR: Size value '%s' is invalid\n", s);
+ exit(1);
+ }
+ if (endptr[0] && endptr[1]) {
+ fprintf(stderr, "ERROR: Illegal suffix contains character '%c' in wrong position\n",
+ endptr[1]);
+ exit(1);
+ }
+ /* strtoll returns LLONG_MAX when overflow, if this happens,
+ * need to call strtoull to get the real size */
+ if (errno == ERANGE && ret == ULLONG_MAX) {
+ fprintf(stderr,
+ "ERROR: Size value '%s' is too large for u64\n", s);
+ exit(1);
+ }
+ if (endptr[0]) {
+ c = tolower(endptr[0]);
switch (c) {
case 'e':
mult *= 1024;
@@ -1646,18 +1679,19 @@ u64 parse_size(char *s)
case 'b':
break;
default:
- fprintf(stderr, "ERROR: Unknown size descriptor "
- "'%c'\n", c);
+ fprintf(stderr, "ERROR: Unknown size descriptor '%c'\n",
+ c);
exit(1);
}
}
- if (s[i] && s[i+1]) {
- fprintf(stderr, "ERROR: Illegal suffix contains "
- "character '%c' in wrong position\n",
- s[i+1]);
- exit(51);
+ /* Check whether ret * mult overflow */
+ if (fls64(ret) + fls64(mult) - 1 > 64) {
+ fprintf(stderr,
+ "ERROR: Size value '%s' is too large for u64\n", s);
+ exit(1);
}
- return strtoull(s, NULL, 10) * mult;
+ ret *= mult;
+ return ret;
}
int open_file_or_dir3(const char *fname, DIR **dirstream, int open_flags)
--
2.0.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v3] btrfs-progs: Improve the parse_size() error message.
2014-06-13 2:55 [PATCH v3] btrfs-progs: Improve the parse_size() error message Qu Wenruo
@ 2014-06-18 15:52 ` David Sterba
0 siblings, 0 replies; 2+ messages in thread
From: David Sterba @ 2014-06-18 15:52 UTC (permalink / raw)
To: Qu Wenruo; +Cc: linux-btrfs, dsterba
On Fri, Jun 13, 2014 at 10:55:57AM +0800, Qu Wenruo wrote:
> v3:
> Don't reparse size twice
> Better u64 overflow check
Thanks. I've tested the limits, overflow checks and negative numbers,
works fine.
^ permalink raw reply [flat|nested] 2+ messages in thread
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