Add support for message-tags

[progval]

Not doing anything with it yet, though.

If that's fine with you, I have another PR ready, to use server-time

[SilverRainZ]

Sorry for replying so late, I will review it ASAP.

[SilverRainZ]

I think we should check the boundary of current_tag_{key,value}_ptr at every time we bump the value of them, Otherwise, we may overflow our stack when encountering malformed messages.

[SilverRainZ]

Use strtok is safer than ptr++.

[progval]

Use strtok is safer than ptr++.

How? The loop needs to look for both ;/= and .

[SilverRainZ]

Use strtok is safer than ptr++.

How? The loop needs to look for both ;/= and .

ptr = strtok(line, delim)(first call), The delim parameter of can be ; = as you want.

See also: https://www.tutorialspoint.com/c_standard_library/c_function_strtok.htm

[progval]

I think we should check the boundary of current_tag_{key,value}_ptr at every time we bump the value of them, Otherwise, we may overflow our stack when encountering malformed messages.

Oh, good point. What if I add this at the beginning of the loop instead?

if (p >= (tags_ptr + TAGS_SIZE_LIMIT)) {
    g_free(imsg->tags);
    goto bad;

As current_tag_{key,value}_ptr are incremented at most once per loop iteration, this should guarantee they don't overflow.

[progval]

ptr = strtok(line, delim)(first call), The delim parameter of can be ; = as you want.

But it can't be all of them at the same time; so I would need to call strtok twice and discard the largest result, this seems wasteful

[SilverRainZ]

Oh, good point. What if I add this at the beginning of the loop instead?

if (p >= (tags_ptr + TAGS_SIZE_LIMIT)) {
    g_free(imsg->tags);
    goto bad;

It is okay and would be better if you print a related error message using `ERR_FR.

As current_tag_{key,value}_ptr are incremented at most once per loop iteration, this should guarantee they don't overflow.

When escaping chars, ptrs are incremented twice?

[SilverRainZ]

But it can't be all of them at the same time; so I would need to call strtok twice and discard the largest result, this seems wasteful

Yes, so there are 2 ways:

1. use strtok, the flow of your code may changed: we can "check all of them" in same time
2. don't change the code, but check whehter *p == '\0' every time after bump it.

[progval]

It is okay and would be better if you print a related error message using `ERR_FR.

Sure

When escaping chars, ptrs are incremented twice?

p is incremented twice, but current_tag_{key,value}_ptr only once

[SilverRainZ]

It is okay and would be better if you print a related error message using `ERR_FR.

Sure

When escaping chars, ptrs are incremented twice?

p is incremented twice, but current_tag_{key,value}_ptr only once

Ahhh, yes, my fault.

[progval]

Done!

[SilverRainZ]

Sorry for delay again, I am quite busy with both my life and work.

I will test the function of this PR weekend, then evently it can be merged.