[PATCH] xfsprogs: mkfs: make strict check on -ialign option

[Wengang Wang]

Though it's clearly said in mkfs.xfs man page that for -ialign option only 1 or
0 are valid values, I would like to make a strict check on it in code.

If a user specified -ialign=y(but he meant -ialign=1 actually), mkfs treats "y"
as "0"(simply by atoi()) thus acts wrongly without complaint. I think we'd better
prevent that from happening, so I made the patch. The patch fails the operation
on values for -ialign option, like "yes", "no", "y", "n".

Signed-off-by: Wengang Wang <wen.gang.wang at oracle.com>
---
 mkfs/xfs_mkfs.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 2d09e36..d7e9eb3 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -1180,14 +1180,17 @@ main(
 			p = optarg;
 			while (*p != '\0') {
 				char	*value;
+				int len;
 
 				switch (getsubopt(&p, (constpp)iopts, &value)) {
 				case I_ALIGN:
 					if (!value)
 						value = "1";
-					iaflag = atoi(value);
-					if (iaflag < 0 || iaflag > 1)
+					len = strlen(value);
+					if (len != 1 || value[0] < '0' ||
+					    value[0] > '1')
 						illegal(value, "i align");
+					iaflag = value[0] - '0';
 					break;
 				case I_LOG:
 					if (!value)
-- 
1.6.6.1