Re: [PATCH v3 1/2] use HOST_NAME_MAX to size buffers for gethostname(2)

["René Scharfe" <l.s.r@web.de>]

Am 19.04.2017 um 21:09 schrieb Torsten Bögershausen:
> On 2017-04-19 19:28, René Scharfe wrote:
> []
> One or two minor comments inline
>> diff --git a/builtin/gc.c b/builtin/gc.c
>> index 2daede7820..4c1c01e87d 100644
>> --- a/builtin/gc.c
>> +++ b/builtin/gc.c
>> @@ -228,21 +228,99 @@ static int need_to_gc(void)
>>   	return 1;
>>   }
>>   
>> +struct pidfile {
>> +	struct strbuf buf;
>> +	char *hostname;
>> +};
>> +
>> +#define PIDFILE_INIT { STRBUF_INIT }
>> +
>> +static void pidfile_release(struct pidfile *pf)
>> +{
>> +	pf->hostname = NULL;
>> +	strbuf_release(&pf->buf);
>> +}
>> +
>> +static int pidfile_read(struct pidfile *pf, const char *path,
>> +			unsigned int max_age_seconds)
>> +{
>> +	int fd;
>> +	struct stat st;
>> +	ssize_t len;
>> +	char *space;
>> +	int rc = -1;
>> +
>> +	fd = open(path, O_RDONLY);
>> +	if (fd < 0)
>> +		return rc;
>> +
>> +	if (fstat(fd, &st))
>> +		goto out;
>> +	if (time(NULL) - st.st_mtime > max_age_seconds)
>> +		goto out;
>> +	if (st.st_size > (size_t)st.st_size)
> 
> Minor: we need xsize_t here ?
> if (st.st_size > xsize_t(st.st_size))

No, xsize_t() would do the same check and die on overflow, and 
pidfile_read() is supposed to handle big pids gracefully.

> 
>> +		goto out;
>> +
>> +	len = strbuf_read(&pf->buf, fd, st.st_size);
>> +	if (len < 0)
>> +		goto out;
>> +
>> +	space = strchr(pf->buf.buf, ' ');
>> +	if (!space) {
>> +		pidfile_release(pf);
>> +		goto out;
>> +	}
>> +	pf->hostname = space + 1;
>> +	*space = '\0';
>> +
>> +	rc = 0;
>> +out:
>> +	close(fd);
>> +	return rc;
>> +}
>> +
>> +static int parse_pid(const char *value, pid_t *ret)
>> +{
>> +	if (value && *value) {
>> +		char *end;
>> +		intmax_t val;
>> +
>> +		errno = 0;
>> +		val = strtoimax(value, &end, 0);
>> +		if (errno == ERANGE)
>> +			return 0;
>> +		if (*end)
>> +			return 0;
>> +		if (labs(val) > maximum_signed_value_of_type(pid_t)) {
>> +			errno = ERANGE;
>> +			return 0;
>> +		}
>> +		*ret = val;
>> +		return 1;
>> +	}
>> +	errno = EINVAL;
>> +	return 0;
>> +}
>> +
>> +static int pidfile_process_exists(const struct pidfile *pf)
>> +{
>> +	pid_t pid;
>> +	return parse_pid(pf->buf.buf, &pid) &&
>> +		(!kill(pid, 0) || errno == EPERM);
>> +}
>> +
>>   /* return NULL on success, else hostname running the gc */
>> -static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
>> +static int lock_repo_for_gc(int force, struct pidfile *pf)
>>   {
>>   	static struct lock_file lock;
>>   	char my_host[128];
> 
> Huh ?
> should this be increased, may be in another path ?

It should, but not in this patch.

René