70 lines
2.1 KiB
C
70 lines
2.1 KiB
C
#include <zinnia/iovec.h>
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#include <zinnia/usercopy.h>
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#include <zinnia/utils.h>
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#include <string.h>
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// Copies between `buf` and the iterator. If `to_iter` is set, data flows from `buf` into the iovecs.
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static errno_t iovec_iter_copy(iovec_iter_t* iter, void* buf, size_t len, bool to_iter, size_t* out_copied) {
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size_t progress = 0;
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errno_t status = 0;
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while (progress < len && iter->current_idx < iter->iovecs_len) {
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iovec_t* vec = &iter->iovecs[iter->current_idx];
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size_t remaining = vec->len - iter->current_offset;
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if (remaining == 0) {
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iter->current_idx++;
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iter->current_offset = 0;
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continue;
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}
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size_t chunk = MIN(remaining, len - progress);
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void* ptr = (void*)(vec->base + iter->current_offset);
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uint8_t* kbuf = (uint8_t*)buf + progress;
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if (iter->user) {
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bool ok = to_iter ? usercopy_write((__user void*)ptr, kbuf, chunk)
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: usercopy_read(kbuf, (const __user void*)ptr, chunk);
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if (!ok) {
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status = EFAULT;
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break;
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}
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} else if (to_iter) {
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memcpy(ptr, kbuf, chunk);
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} else {
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memcpy(kbuf, ptr, chunk);
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}
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progress += chunk;
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iter->current_offset += chunk;
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iter->total_offset += chunk;
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}
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if (out_copied)
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*out_copied = progress;
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return status;
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}
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iovec_iter_t iovec_iter_kernel(iovec_t* iovecs, size_t count) {
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size_t total = 0;
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for (size_t i = 0; i < count; i++)
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total += iovecs[i].len;
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return (iovec_iter_t){
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.iovecs = iovecs,
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.iovecs_len = count,
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.total_len = total,
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.total_offset = 0,
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.current_idx = 0,
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.current_offset = 0,
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.user = false,
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};
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}
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errno_t iovec_iter_copy_to(iovec_iter_t* iter, const void* src, size_t len, size_t* out_copied) {
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return iovec_iter_copy(iter, (void*)src, len, true, out_copied);
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}
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errno_t iovec_iter_copy_from(iovec_iter_t* iter, void* dst, size_t len, size_t* out_copied) {
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return iovec_iter_copy(iter, dst, len, false, out_copied);
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}
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