Re: [patch 1/2] staging: speakup: add function to convert dev name to number

[Dan Carpenter]

On Tue, Jun 13, 2017 at 11:37:03PM +0100, okash.khawaja@xxxxxxxxx wrote:
> The function converts strings like ttyS0 and ttyUSB0 to dev_t like
> (4, 64) and (188, 0). Subsequent patch in this set will call it to
> convert user-supplied device into device number. The function does
> some basic sanity checks on the string passed in. It currently supports
> ttyS*, ttyUSB* and, for selected synths, lp*.
> 
> In order to do this, the patch also introduces a string member variable
> named 'dev' to struct spk_synth. 'dev' represents the device name -
> ttyUSB0 etc - which needs conversion to dev_t.
> 
> Signed-off-by: Okash Khawaja <okash.khawaja@xxxxxxxxx>
> Reviewed-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
> 
> ---
>  drivers/staging/speakup/spk_priv.h  |    2 
>  drivers/staging/speakup/spk_ttyio.c |  105 ++++++++++++++++++++++++++++++++++++
>  drivers/staging/speakup/spk_types.h |    1 
>  3 files changed, 108 insertions(+)
> 
> --- a/drivers/staging/speakup/spk_priv.h
> +++ b/drivers/staging/speakup/spk_priv.h
> @@ -40,6 +40,8 @@
>  
>  #define KT_SPKUP 15
>  #define SPK_SYNTH_TIMEOUT 100000 /* in micro-seconds */
> +#define SYNTH_DEFAULT_DEV "ttyS0"
> +#define SYNTH_DEFAULT_SER 0
>  
>  const struct old_serial_port *spk_serial_init(int index);
>  void spk_stop_serial_interrupt(void);
> --- a/drivers/staging/speakup/spk_ttyio.c
> +++ b/drivers/staging/speakup/spk_ttyio.c
> @@ -7,6 +7,13 @@
>  #include "spk_types.h"
>  #include "spk_priv.h"
>  
> +/* Supported device types */
> +#define DEV_PREFIX_TTYS "ttyS"
> +#define DEV_PREFIX_TTYUSB "ttyUSB"
> +#define DEV_PREFIX_LP "lp"
> +
> +const char *lp_supported[] = { "acntsa", "bns", "dummy", "txprt" };
> +
>  struct spk_ldisc_data {
>  	char buf;
>  	struct semaphore sem;
> @@ -16,6 +23,104 @@ struct spk_ldisc_data {
>  static struct spk_synth *spk_ttyio_synth;
>  static struct tty_struct *speakup_tty;
>  
> +static int name_to_dev(const char *name, dev_t *dev_no)
> +{
> +        int maj = -1, min = -1;
> +
> +        if (strncmp(name, DEV_PREFIX_TTYS, strlen(DEV_PREFIX_TTYS)) == 0) {
> +                if (kstrtoint(name + strlen(DEV_PREFIX_TTYS), 10, &min)) {
> +			pr_err("speakup: Invalid ser param. Must be \
> +					between 0 and 191 inclusive.\n");

String needs fixed.

> +                        return -EINVAL;

Preserve the error code from kstrtoint().

> +                }
> +                maj = 4;
> +
> +                if (min < 0 || min > 191) {
> +			pr_err("speakup: Invalid ser param. Must be \
> +					between 0 and 191 inclusive.\n");


This too.

> +                        return -EINVAL;
> +                }
> +                min = min + 64;
> +        } else if (strncmp(name, DEV_PREFIX_TTYUSB, strlen(DEV_PREFIX_TTYUSB))
> +			== 0) {
> +                if (kstrtoint(name + strlen(DEV_PREFIX_TTYUSB), 10, &min)) {
> +                        pr_err("speakup: Invalid ttyUSB number. \
> +					Must be a number from 0 onwards\n");
> +                        return -EINVAL;

Same.

> +                }
> +                maj = 188;
> +
> +                if (min < 0) {
> +                        pr_err("speakup: Invalid ttyUSB number. \
> +					Must be a number from 0 onwards\n");

Same.

> +                        return -EINVAL;
> +                }
> +        } else if (strncmp(name, DEV_PREFIX_LP, strlen(DEV_PREFIX_LP)) == 0) {
> +                if (kstrtoint(name + strlen(DEV_PREFIX_LP), 10, &min)) {
> +                        pr_warn("speakup: Invalid lp number. \
> +					Must be a number from 0 onwards\n");
> +                        return -EINVAL;

Same.  Preserve.

> +                }
> +                maj = 6;
> +
> +                if (min < 0) {
> +                        pr_warn("speakup: Invalid lp number. \
> +					Must be a number from 0 onwards\n");

Again.

> +                        return -EINVAL;
> +                }
> +        }
> +
> +        if (maj == -1 || min == -1)
> +                return -EINVAL;
> +
> +        /* if here, maj and min must be valid */
> +        *dev_no = MKDEV(maj, min);
> +
> +        return 0;
> +}
> +
> +int ser_to_dev(int ser, dev_t *dev_no)
> +{
> +	if (ser < 0 || ser > (255 - 64)) {
> +                pr_err("speakup: Invalid ser param. \
> +				Must be between 0 and 191 inclusive.\n");

String.  I feel like 191 and 255 - 64 are the same.  Let's just use 191
everywhere.

> +
> +		return -EINVAL;
> +        }
> +
> +	*dev_no = MKDEV(4, (64 + ser));
> +	return 0;
> +}
> +
> +static int get_dev_to_use(struct spk_synth *synth, dev_t *dev_no)
> +{
> +	/* use ser only when dev is not specified */
> +	if (strcmp(synth->dev, SYNTH_DEFAULT_DEV) || synth->ser == SYNTH_DEFAULT_SER) {
> +		/* for /dev/lp* check if synth is supported */
> +		if (strncmp(synth->dev, DEV_PREFIX_LP, strlen(DEV_PREFIX_LP)) == 0) {
> +			int i;
> +
> +			for (i = 0; i < ARRAY_SIZE(lp_supported); i++) {
> +				if (strcmp(synth->name, lp_supported[i]) == 0)
> +					break;
> +			}
> +
> +			if (i >= ARRAY_SIZE(lp_supported)) {
> +				pr_err("speakup: lp* is only supported on:");
> +				for (i = 0; i < ARRAY_SIZE(lp_supported); i++)
> +					pr_cont(" %s", lp_supported[i]);
> +				pr_cont("\n");
> +
> +				return -ENOTSUPP;
> +			}
> +		}
> +
> +		return name_to_dev(synth->dev, dev_no);
> +	}
> +
> +	return ser_to_dev(synth->ser, dev_no);
> +}
> +
>  static int spk_ttyio_ldisc_open(struct tty_struct *tty)
>  {
>  	struct spk_ldisc_data *ldisc_data;
> --- a/drivers/staging/speakup/spk_types.h
> +++ b/drivers/staging/speakup/spk_types.h
> @@ -169,6 +169,7 @@ struct spk_synth {
>  	int jiffies;
>  	int full;
>  	int ser;
> +	char *dev;

Could you call it "dev_name" instead?  I normally expect "dev" to be a
device struct.

regards,
dan carpenter