On 07.03.24 11:38, Henry Wang wrote:
Below error can be seen when doing Yocto build of the toolstack:| io.c: In function 'p9_error': | io.c:684:5: error: ignoring return value of 'strerror_r' declared with attribute 'warn_unused_result' [-Werror=unused-result] | 684 | strerror_r(err, ring->buffer, ring->ring_size); | | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | cc1: all warnings being treated as errors Fix the build by using strerror() to replace strerror_r(). Since strerror() is thread-unsafe, use a separate local mutex to protect the action. The steps would then become: Acquire the mutex first, invoke strerror(), copy the string from strerror() to the designated buffer and then drop the mutex. Signed-off-by: Henry Wang <xin.wa...@amd.com> --- tools/9pfsd/io.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/tools/9pfsd/io.c b/tools/9pfsd/io.c index adb887c7d9..2b80c9528d 100644 --- a/tools/9pfsd/io.c +++ b/tools/9pfsd/io.c @@ -680,8 +680,18 @@ static bool name_ok(const char *str) static void p9_error(struct ring *ring, uint16_t tag, uint32_t err) { unsigned int erroff; + static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; + char *strerror_str; + RING_IDX strerror_len = 0, copy_len = 0; + + pthread_mutex_lock(&mutex); + strerror_str = strerror(err); + strerror_len = strlen(strerror_str) + 1; + copy_len = min(strerror_len, ring->ring_size);
Hmm, I think we even _need_ to cap the string earlier. A string in the 9pfs protocol is a 2 byte length field plus the string. In case of a ring larger than 65535 bytes this would mean the result of strerror() could (in theory) overflow the string format of 9pfs. Additionally the string should be a _short_ description of the error, so I'd like to suggest to not use ring_size as the upper bound for the string length, but a fixed value defined as a macro, e.g.: #define MAX_ERRSTR_LEN 80 Juergen
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