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Fix nio read/write pseudo files #206

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Fix nio read/write pseudo files #206

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113 changes: 69 additions & 44 deletions nio/src/main/java/com/topjohnwu/superuser/internal/OpenFile.java
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Original file line number Diff line number Diff line change
Expand Up @@ -116,10 +116,18 @@ synchronized void sync(boolean metadata) throws ErrnoException, IOException {
synchronized int pread(int len, long offset) throws ErrnoException, IOException {
if (fd == null || write == null)
throw new ClosedChannelException();
final long result;
long result;
if (!FORCE_NO_SPLICE && Build.VERSION.SDK_INT >= 28) {
Int64Ref inOff = offset < 0 ? null : new Int64Ref(offset);
result = FileUtils.splice(fd, inOff, write, null, len, 0);
try {
Int64Ref inOff = offset < 0 ? null : new Int64Ref(offset);
result = FileUtils.splice(fd, inOff, write, null, len, 0);
} catch (ErrnoException e) {
// Fallback for pseudo files that do not support splice
if (e.errno == OsConstants.EINVAL)
result = preadFb(len, offset);
else
throw e;
}
} else {
StructStat st = getStat();
if (OsConstants.S_ISREG(st.st_mode) || OsConstants.S_ISBLK(st.st_mode)) {
Expand All @@ -128,63 +136,80 @@ synchronized int pread(int len, long offset) throws ErrnoException, IOException
result = FileUtils.sendfile(write, fd, inOff, len);
} else {
// Fallback to copy into internal buffer
ByteBuffer buf = getBuf();
buf.limit(Math.min(len, buf.capacity()));
if (offset < 0) {
Os.read(fd, buf);
} else {
Os.pread(fd, buf, offset);
}
buf.flip();
result = buf.remaining();
// Need to write all bytes
for (int sz = (int) result; sz > 0; ) {
sz -= Os.write(write, buf);
}
result = preadFb(len, offset);
}
}
return (int) result;
}

private int preadFb(int len, long offset) throws ErrnoException, IOException {
ByteBuffer buf = getBuf();
buf.limit(Math.min(len, buf.capacity()));
if (offset < 0) {
Os.read(fd, buf);
} else {
Os.pread(fd, buf, offset);
}
buf.flip();
int result = buf.remaining();
// Need to write all bytes
for (int sz = (int) result; sz > 0; ) {
sz -= Os.write(write, buf);
}
return result;
}

synchronized int pwrite(int len, long offset, boolean exact) throws ErrnoException, IOException {
if (fd == null || read == null)
throw new ClosedChannelException();
if (!FORCE_NO_SPLICE && Build.VERSION.SDK_INT >= 28) {
Int64Ref outOff = offset < 0 ? null : new Int64Ref(offset);
if (exact) {
int sz = len;
while (sz > 0) {
sz -= FileUtils.splice(read, null, fd, outOff, sz, 0);
try {
Int64Ref outOff = offset < 0 ? null : new Int64Ref(offset);
if (exact) {
int sz = len;
while (sz > 0) {
sz -= FileUtils.splice(read, null, fd, outOff, sz, 0);
}
return len;
} else {
return (int) FileUtils.splice(read, null, fd, outOff, len, 0);
}
return len;
} else {
return (int) FileUtils.splice(read, null, fd, outOff, len, 0);
} catch (ErrnoException e) {
// Fallback for pseudo files that do not support splice
if (e.errno == OsConstants.EINVAL)
return pwriteFb(len, offset, exact);
else
throw e;
}
} else {
// Unfortunately, sendfile does not allow reading from pipes.
// Manually read into an internal buffer then write to output.
ByteBuffer buf = getBuf();
int sz = 0;
buf.limit(len);
if (exact) {
while (len > sz) {
sz += Os.read(read, buf);
}
} else {
sz = Os.read(read, buf);
return pwriteFb(len, offset, exact);
}
}

private int pwriteFb(int len, long offset, boolean exact) throws ErrnoException, IOException {
ByteBuffer buf = getBuf();
int sz = 0;
buf.limit(len);
if (exact) {
while (len > sz) {
sz += Os.read(read, buf);
}
len = sz;
buf.flip();
while (sz > 0) {
if (offset < 0) {
sz -= Os.write(fd, buf);
} else {
int w = Os.pwrite(fd, buf, offset);
sz -= w;
offset += w;
}
} else {
sz = Os.read(read, buf);
}
len = sz;
buf.flip();
while (sz > 0) {
if (offset < 0) {
sz -= Os.write(fd, buf);
} else {
int w = Os.pwrite(fd, buf, offset);
sz -= w;
offset += w;
}
return len;
}
return len;
}
}