-------- Original Message --------
Subject: Re: [PATCH v2] btrfs-progs: Improve the parse_size() error message.
From: David Sterba <dsterba@xxxxxxx>
To: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
Date: 2014年06月12日 18:15
On Thu, May 29, 2014 at 09:42:11AM +0800, Qu Wenruo wrote:
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@xxxxxxxxxxxxxx>
---
utils.c | 56 +++++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 39 insertions(+), 17 deletions(-)
diff --git a/utils.c b/utils.c
index 392c5cf..499f08f 100644
--- a/utils.c
+++ b/utils.c
@@ -1612,18 +1612,45 @@ scan_again:
u64 parse_size(char *s)
{
- int i;
char c;
+ char *endptr;
u64 mult = 1;
+ long long int signed_ret;
+ 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);
We never pass a NULL pointer to parse_size so this check will be always
false. Previously it verified that there are at least some digits.
Command like 'mkfs.btrfs -b /dev/sda' *WILL* pass NULL pointer to
parse_size(), so the check is needed.
}
-
- if (s[i]) {
- c = tolower(s[i]);
+ signed_ret = strtoll(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);
+ }
+ if (signed_ret <= 0) {
+ fprintf(stderr,
+ "ERROR: Size value '%s' is less equal than 0\n", s);
+ exit(1);
+ }
+ /* strtoll returns LLONG_MAX when overflow, if this happens,
+ * need to call strtoull to get the real size */
+ if (errno == ERANGE && signed_ret == LLONG_MAX) {
+ ret = strtoull(s, NULL, 10);
Why do you parse the number twice? Negative sizes are currently not used
so you can reject them.
I will change the patch to judgement leading '-' and reject the value.
+ if (errno == ERANGE && ret == ULLONG_MAX) {
+ fprintf(stderr,
+ "ERROR: Size value '%s' is too large for u64\n",
+ s);
+ exit(1);
+ }
+ } else
+ ret = signed_ret;
+ if (endptr[0]) {
+ c = tolower(endptr[0]);
switch (c) {
case 'e':
mult *= 1024;
@@ -1646,18 +1673,13 @@ 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);
- }
- return strtoull(s, NULL, 10) * mult;
+
+ ret *= mult;
Although there was no overflow check before, I think it should be here.
Eg. 12345678P is a valid size string but the result does not fit u64.
Right, I will check the overflow here.
Thanks,
Qu
+ return ret;
}
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