wasi: add getEnvMap #2390
wasi: add getEnvMap #2390
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std/os.zig
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| if (env) |ptr| { | ||
| var line_i: usize = 0; | ||
| while (ptr[line_i] != 0 and ptr[line_i] != '=') : (line_i += 1) {} | ||
| if (ptr[line_i] != '=') { |
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I think this can be an assertion. If the WASI functions don't do what they're documented to do, that's definitely going to cause undefined behavior. And environ_get is documented to return the environment string with the format key=value, right?
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The documentation doesn't say anything. wasmtime returns it in key=value, wasmer returns argv[0] which is definitely a bug.
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We have 2 choices here:
- make the zig code assume the WASI host is correct and do a little bit of prediction about the specifications of the behavior (
key=value) and allow host bugs to cause bugs in Zig code that uses them. - recognize and work around WASI host bugs & undocumented behavior.
Given that WASI is so brand new, my preference is (1). That means that we recommend Debug or ReleaseSafe builds for now - due to upstream/downstream bugs - and then work with the third party projects to get their bugs fixed / documentation clarified. We can point to the zig standard library and say "this is how we want to implement it, it will work like this if you fix the bug / clarify the docs".
std/os.zig
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| for (environ) |env| { | ||
| if (env) |ptr| { | ||
| var line_i: usize = 0; | ||
| while (ptr[line_i] != 0 and ptr[line_i] != '=') : (line_i += 1) {} |
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I'm fine with this, but you might consider using std.mem.separate
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Combining this and the other comment about assert, you could do this:
const line = std.mem.toSlice(u8, ptr);
var it = std.mem.separate(line, "=");
const key = it.next().?;
const value = it.next().?;There was a problem hiding this comment.
Done. This also cleanly handles wasmer.
See: WebAssembly/WASI#27 for the null pointer todo