mirror of
https://github.com/fluencelabs/musl
synced 2025-05-18 18:21:31 +00:00
3f25354e62
unfortunately in dynamic-linked programs, these macros cause pthread_self to be initialized, which costs a couple syscalls, and (much worse) would necessarily fail, crash, and burn on ancient (2.4 and earlier) kernels where setting up a thread pointer does not work. i'd like to do this in a more generic way that avoids all use of cleanup push/pop before pthread_self has been successfully called and avoids ugly if/else constructs like the one in this commit, but for now, this will suffice.
50 lines
1.1 KiB
C
50 lines
1.1 KiB
C
#include "stdio_impl.h"
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#include <pthread.h>
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static void cleanup(void *p)
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{
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FILE *f = p;
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if (!f->lockcount) __unlockfile(f);
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}
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size_t __stdio_write(FILE *f, const unsigned char *buf, size_t len)
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{
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struct iovec iovs[2] = {
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{ .iov_base = f->wbase, .iov_len = f->wpos-f->wbase },
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{ .iov_base = (void *)buf, .iov_len = len }
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};
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struct iovec *iov = iovs;
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size_t rem = iov[0].iov_len + iov[1].iov_len;
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int iovcnt = 2;
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ssize_t cnt;
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for (;;) {
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if (libc.main_thread) {
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pthread_cleanup_push(cleanup, f);
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cnt = syscall_cp(SYS_writev, f->fd, iov, iovcnt);
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pthread_cleanup_pop(0);
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} else {
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cnt = syscall(SYS_writev, f->fd, iov, iovcnt);
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}
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if (cnt == rem) {
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f->wend = f->buf + f->buf_size;
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f->wpos = f->wbase = f->buf;
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return len;
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}
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if (cnt < 0) {
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f->wpos = f->wbase = f->wend = 0;
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f->flags |= F_ERR;
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return iovcnt == 2 ? 0 : len-iov[0].iov_len;
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}
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rem -= cnt;
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if (cnt > iov[0].iov_len) {
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f->wpos = f->wbase = f->buf;
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cnt -= iov[0].iov_len;
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iov++; iovcnt--;
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} else if (iovcnt == 2) {
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f->wbase += cnt;
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}
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iov[0].iov_base = (char *)iov[0].iov_base + cnt;
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iov[0].iov_len -= cnt;
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}
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}
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