[PATCH nvme-cli] nvme: fix asprintf return value check

[PATCH nvme-cli] nvme: fix asprintf return value check

[Chaitanya Kulkarni]

The asprintf(3) function resturns -1 on error not 1. Fix that.

Fixes a032a481d74 ("nvme: fix compiler warnings")

Suggested-by: Kev Dorman <kdorman036@gmail.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 nvme-topology.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/nvme-topology.c b/nvme-topology.c
index e938f23..4dbadce 100644
--- a/nvme-topology.c
+++ b/nvme-topology.c
@@ -357,9 +357,9 @@ static int verify_legacy_ns(struct nvme_namespace *n)
 		char tmp_address[64] = "";
 		legacy_get_pci_bdf(path, tmp_address);
 		if (tmp_address[0]) {
-			if (asprintf(&n->ctrl->transport, "pcie") != 1)
+			if (asprintf(&n->ctrl->transport, "pcie") == -1)
 				return -1;
-			if (asprintf(&n->ctrl->address, "%s", tmp_address) != 1)
+			if (asprintf(&n->ctrl->address, "%s", tmp_address) == -1)
 				return -1;
 		}
 	}
-- 
2.22.1


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Re: [PATCH nvme-cli] nvme: fix asprintf return value check

[Bart Van Assche]

On 2020-04-24 22:58, Chaitanya Kulkarni wrote:
> diff --git a/nvme-topology.c b/nvme-topology.c
> index e938f23..4dbadce 100644
> --- a/nvme-topology.c
> +++ b/nvme-topology.c
> @@ -357,9 +357,9 @@ static int verify_legacy_ns(struct nvme_namespace *n)
>  		char tmp_address[64] = "";
>  		legacy_get_pci_bdf(path, tmp_address);
>  		if (tmp_address[0]) {
> -			if (asprintf(&n->ctrl->transport, "pcie") != 1)
> +			if (asprintf(&n->ctrl->transport, "pcie") == -1)
>  				return -1;
> -			if (asprintf(&n->ctrl->address, "%s", tmp_address) != 1)
> +			if (asprintf(&n->ctrl->address, "%s", tmp_address) == -1)
>  				return -1;
>  		}
>  	}

How about using "< 0" to check for errors? I think that's a more widely
used approach to check for errors than checking for "== -1".

Will a memory leak occur if the first asprintf() call succeeds and the
second asprintf() call fails?

Thanks,

Bart.

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Re: [PATCH nvme-cli] nvme: fix asprintf return value check

[Chaitanya Kulkarni]

> How about using "< 0" to check for errors? I think that's a more widely
> used approach to check for errors than checking for "== -1".
>
> Will a memory leak occur if the first asprintf() call succeeds and the
> second asprintf() call fails?
>
> Thanks,
>
> Bart.
>

Thanks for the comment, will send a V2.


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