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/*
* Copyright 2024 The Emscripten Authors. All rights reserved.
* Emscripten is available under two separate licenses, the MIT license and the
* University of Illinois/NCSA Open Source License. Both these licenses can be
* found in the LICENSE file.
*/
#include <assert.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <unistd.h>
#include <emscripten.h>
EM_JS_DEPS(main, "$ERRNO_CODES");
void setup(void) {
EM_ASM(
var device = FS.makedev(80, 0);
FS.registerDevice(device, {
write: function(stream, buffer, offset, length, pos) {
if (length === 0) {
return 0;
}
// Only do a partial write of one byte each time
out('TO DEVICE: ' + JSON.stringify(String.fromCharCode(buffer[offset])));
return 1;
}
});
FS.mkdev('/device', device);
);
}
// Run the test with writev directly
void test_writev_direct(void) {
int fd = open("/device", O_WRONLY);
assert(fd);
struct iovec iovs[] = {{.iov_base = "ABC", .iov_len = 3},
{.iov_base = "XYZ", .iov_len = 3}};
struct iovec* iov = iovs;
size_t rem = iov[0].iov_len + iov[1].iov_len;
int iovcnt = 2;
ssize_t cnt;
for (;;) {
cnt = writev(fd, iov, iovcnt);
assert(cnt >= 0);
if (cnt == rem) {
// All data written
break;
}
rem -= cnt;
if (cnt > iov[0].iov_len) {
cnt -= iov[0].iov_len;
iov++;
iovcnt--;
}
iov[0].iov_base = (char*)iov[0].iov_base + cnt;
iov[0].iov_len -= cnt;
}
close(fd);
}
// Run the test using stdio, this test is dependent on specific buffering used
// and is included here as this code most closely matches the original bug
// report
void test_via_stdio(void) {
FILE* f = fopen("/device", "w");
assert(f);
// Use line buffering. The bug is exposed with line buffering because with
// line buffering two entries in __stdio_write's iovs are used.
setvbuf(f, NULL, _IOLBF, 0);
fputs("abc", f);
fputs("\n", f);
fflush(f);
fclose(f);
}
int main() {
setup();
test_writev_direct();
test_via_stdio();
printf("done\n");
return 0;
}
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