| Message ID | 20231213164246.1021885-13-lee@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 3e42084a1c4790364c28b5cafd5c66fc25396a64 |
| Headers | show |
| Series | usb: Replace {v}snprintf() variants with safer alternatives | expand |
On Wed, Dec 13, 2023 at 04:42:41PM +0000, Lee Jones wrote: > Since snprintf() has the documented, but still rather strange trait of > returning the length of the data that *would have been* written to the > array if space were available, rather than the arguably more useful > length of data *actually* written, it is usually considered wise to use > something else instead in order to avoid confusion. > > In the case of sysfs call-backs, new wrappers exist that do just that. > > Link: https://lwn.net/Articles/69419/ > Link: https://github.com/KSPP/linux/issues/105 > Cc: Alan Stern <stern@rowland.harvard.edu> > Cc: usb-storage@lists.one-eyed-alien.net > Signed-off-by: Lee Jones <lee@kernel.org> > --- Acked-by: Alan Stern <stern@rowland.harvard.edu>
diff --git a/drivers/usb/storage/sierra_ms.c b/drivers/usb/storage/sierra_ms.c index 0774ba22fb66e..177fa6cd143ab 100644 --- a/drivers/usb/storage/sierra_ms.c +++ b/drivers/usb/storage/sierra_ms.c @@ -98,26 +98,26 @@ static ssize_t truinst_show(struct device *dev, struct device_attribute *attr, struct usb_device *udev = interface_to_usbdev(intf); int result; if (swi_tru_install == TRU_FORCE_MS) { - result = snprintf(buf, PAGE_SIZE, "Forced Mass Storage\n"); + result = sysfs_emit(buf, "Forced Mass Storage\n"); } else { swocInfo = kmalloc(sizeof(struct swoc_info), GFP_KERNEL); if (!swocInfo) { - snprintf(buf, PAGE_SIZE, "Error\n"); + sysfs_emit(buf, "Error\n"); return -ENOMEM; } result = sierra_get_swoc_info(udev, swocInfo); if (result < 0) { dev_dbg(dev, "SWIMS: failed SWoC query\n"); kfree(swocInfo); - snprintf(buf, PAGE_SIZE, "Error\n"); + sysfs_emit(buf, "Error\n"); return -EIO; } debug_swoc(dev, swocInfo); - result = snprintf(buf, PAGE_SIZE, - "REV=%02d SKU=%04X VER=%04X\n", - swocInfo->rev, - swocInfo->LinuxSKU, - swocInfo->LinuxVer); + result = sysfs_emit(buf, + "REV=%02d SKU=%04X VER=%04X\n", + swocInfo->rev, + swocInfo->LinuxSKU, + swocInfo->LinuxVer); kfree(swocInfo); } return result;
Since snprintf() has the documented, but still rather strange trait of returning the length of the data that *would have been* written to the array if space were available, rather than the arguably more useful length of data *actually* written, it is usually considered wise to use something else instead in order to avoid confusion. In the case of sysfs call-backs, new wrappers exist that do just that. Link: https://lwn.net/Articles/69419/ Link: https://github.com/KSPP/linux/issues/105 Cc: Alan Stern <stern@rowland.harvard.edu> Cc: usb-storage@lists.one-eyed-alien.net Signed-off-by: Lee Jones <lee@kernel.org> --- drivers/usb/storage/sierra_ms.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)