[alsa-devel] sound: bebop: strncmp length oddity
15 isn't the length of the string, is that really what's desired? linux/next/sound/firewire/bebob/bebop.c ----------------------------- static bool check_audiophile_booted(struct fw_unit *unit) { char name[24] = {0}; if (fw_csr_string(unit->directory, CSR_MODEL, name, sizeof(name)) < 0) return false; return strncmp(name, "FW Audiophile Bootloader", 15) != 0; }
On Sat, 29 Oct 2016 23:37:00 +0200, Joe Perches wrote:
15 isn't the length of the string, is that really what's desired?
linux/next/sound/firewire/bebob/bebop.c
-----------------------------
static bool check_audiophile_booted(struct fw_unit *unit) { char name[24] = {0};
if (fw_csr_string(unit->directory, CSR_MODEL, name, sizeof(name)) < 0) return false;
return strncmp(name, "FW Audiophile Bootloader", 15) != 0; }
Indeed it looks bogus. Even "FW...." string is already 24 letters, so it's over name[] array size. Sakamoto-san, could you fix it properly? thanks, Takashi
s/bebop/bebob/ (BeBoB is 'BridgeCo enhanced Breakout Box'.) I'm sorry to miss this post, Joe. I was busy to prepare for Audio mini-conference on Linux Plumber Conference. I realized that Nicolas posted a patch for this issue. [alsa-devel] [PATCH 1/1] ALSA: bebob: use the right string length in check_audiophile_booted() http://mailman.alsa-project.org/pipermail/alsa-devel/2016-October/114073.htm... On Nov 17 2016 20:47, Takashi Iwai wrote:
On Sat, 29 Oct 2016 23:37:00 +0200, Joe Perches wrote:
15 isn't the length of the string, is that really what's desired?
linux/next/sound/firewire/bebob/bebop.c
-----------------------------
static bool check_audiophile_booted(struct fw_unit *unit) { char name[24] = {0};
if (fw_csr_string(unit->directory, CSR_MODEL, name, sizeof(name)) < 0) return false;
return strncmp(name, "FW Audiophile Bootloader", 15) != 0; }
Indeed it looks bogus. Even "FW...." string is already 24 letters, so it's over name[] array size.
Sakamoto-san, could you fix it properly?
It's OK just to compare first a few characters, while I left whole string for our information because model-specific information is easily lost. For M-Audio's FireWire Audiophile, modalias of 'ieee1394:ven00000D6Cmo00010060sp' hits this unit only. However the unit has two states relevant to loaded firmware. Initial firmware returns 'FW Audiophile Bootloader', while functional firmware returns 'FW Audiophile'. Just comparing the first 15 characters is the shortest way to defferentiate them. (Actually 14 characters. I guess that I did avoid comparison based on LWS...) Therefore, changing comparison range is not for bug fix, just for readers. But I agree with these patches because the code is a bit confusing. I'll post a patch soon for this aim with appropriate information, sorry for Nicolas. Thanks Takashi Sakamoto
On 17/11/16 21:07, Takashi Sakamoto wrote:
On Nov 17 2016 20:47, Takashi Iwai wrote:
On Sat, 29 Oct 2016 23:37:00 +0200, Joe Perches wrote:
15 isn't the length of the string, is that really what's desired?
linux/next/sound/firewire/bebob/bebop.c
-----------------------------
static bool check_audiophile_booted(struct fw_unit *unit) { char name[24] = {0};
if (fw_csr_string(unit->directory, CSR_MODEL, name, sizeof(name)) < 0) return false;
return strncmp(name, "FW Audiophile Bootloader", 15) != 0; }
Indeed it looks bogus. Even "FW...." string is already 24 letters, so it's over name[] array size.
Sakamoto-san, could you fix it properly?
It's OK just to compare first a few characters, while I left whole string for our information because model-specific information is easily lost.
For M-Audio's FireWire Audiophile, modalias of 'ieee1394:ven00000D6Cmo00010060sp' hits this unit only. However the unit has two states relevant to loaded firmware. Initial firmware returns 'FW Audiophile Bootloader', while functional firmware returns 'FW Audiophile'. Just comparing the first 15 characters is the shortest way to defferentiate them. (Actually 14 characters. I guess that I did avoid comparison based on LWS...)
Therefore, changing comparison range is not for bug fix, just for readers. But I agree with these patches because the code is a bit confusing. I'll post a patch soon for this aim with appropriate information, sorry for Nicolas.
All right, so long as the code is modified in a way that makes it more consistent, I am all right. It is one patch less I need to care about :) Nicolas
participants (4)
-
Joe Perches -
Nicolas Iooss -
Takashi Iwai -
Takashi Sakamoto