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Fix truncation of bytes/bytes_read/bytes_written stats #156

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Fix truncation of bytes/bytes_read/bytes_written stats #156

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6 changes: 3 additions & 3 deletions ext/libmemcached-0.32/libmemcached/memcached_stats.c
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Original file line number Diff line number Diff line change
Expand Up @@ -87,15 +87,15 @@ static memcached_return set_data(memcached_stat_st *memc_stat, char *key, char *
}
else if (!strcmp("bytes_read", key))
{
memc_stat->bytes_read= (uint32_t) strtoll(value, (char **)NULL, 10);
memc_stat->bytes_read= (uint64_t) strtoll(value, (char **)NULL, 10);
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Should we be using strtoull so we aren't casting away the sign?

It seems like there might be an edge case if you had a value greater than LLONG_MAX but less than ULLONG_MAX. The manual says the value would be truncated to LLONG_MAX, giving us 63 bits instead of 64.

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Newer versions of libmemcached do use strtoull, so I suspect you're correct. However what I changed the code to here matches the other 64-bit stats (like cmd_get a few lines below the end of this diff). I wanted to make as small a change as possible to fix the immediate issue, which is truncating to 32 bits. It seems unlikely that we would end up with a value greater than 2^63 (8 exabytes) here.

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That said, if a more complete fix is desired I'd be happy to switch to strtoull everywhere.

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Yeah, after I saw the diff I looked at the whole file and saw strtoll being used everywhere for unsigned left hand values and realized why you went this route.

}
else if (!strcmp("bytes_written", key))
{
memc_stat->bytes_written= (uint32_t) strtoll(value, (char **)NULL, 10);
memc_stat->bytes_written= (uint64_t) strtoll(value, (char **)NULL, 10);
}
else if (!strcmp("bytes", key))
{
memc_stat->bytes= (uint32_t) strtoll(value, (char **)NULL, 10);
memc_stat->bytes= (uint64_t) strtoll(value, (char **)NULL, 10);
}
else if (!strcmp("curr_connections", key))
{
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