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https://git.proxmox.com/git/wasi-libc
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cf366c06d1
`lseek(x, 0, SEEK_CUR)` has no effect other than to return the current file offset. The patch here uses a macro with `__builtin_constant_p` to recognize this case and rewrite it to a library call that uses `fd_tell` rather than `fd_seek`, so that programs that don't need actual seeking don't end up importing `fd_seek`. This is also the first usage of `__wasi_fd_tell` in WASI libc, so this adds it to undefined-symbols.txt.
15 lines
426 B
C
15 lines
426 B
C
#include <wasi/core.h>
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#include <errno.h>
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off_t __wasilibc_tell(int fildes) {
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__wasi_filesize_t offset;
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__wasi_errno_t error = __wasi_fd_tell(fildes, &offset);
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if (error != 0) {
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// lseek returns ESPIPE on when called on a pipe, socket, or fifo,
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// which on WASI would translate into ENOTCAPABLE.
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errno = error == ENOTCAPABLE ? ESPIPE : error;
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return -1;
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}
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return offset;
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}
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