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Fix read() on posix
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@andralex
andralex committed Feb 5, 2015
1 parent 581f6d0 commit 524efa6
Showing 1 changed file with 84 additions and 108 deletions.
192 changes: 84 additions & 108 deletions std/file.d
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Expand Up @@ -191,128 +191,104 @@ Returns: Untyped array of bytes _read.
Throws: $(D FileException) on error.
*/
void[] read(in char[] name, size_t upTo = size_t.max) @safe
version (Posix) void[] read(in char[] name, size_t upTo = size_t.max) @trusted
{
import std.algorithm : min;
import std.array : uninitializedArray;
import core.memory : GC;

// A few internal configuration parameters {
enum size_t
minInitialAlloc = 1024 * 4,
maxInitialAlloc = size_t.max / 2,
sizeIncrement = 1024 * 16,
maxSlackMemoryAllowed = 1024;
// }

immutable fd = core.sys.posix.fcntl.open(name.tempCString,
core.sys.posix.fcntl.O_RDONLY);
cenforce(fd != -1, name);
scope(exit) core.sys.posix.unistd.close(fd);

stat_t statbuf = void;
cenforce(fstat(fd, &statbuf) == 0, name);

immutable initialAlloc = to!size_t(statbuf.st_size
? min(statbuf.st_size + 1, maxInitialAlloc)
: minInitialAlloc);
void[] result = uninitializedArray!(ubyte[])(initialAlloc);
scope(failure) delete result;
size_t size = 0;

for (;;)
{
immutable actual = core.sys.posix.unistd.read(fd, result.ptr + size,
min(result.length, upTo) - size);
cenforce(actual != -1, name);
if (actual == 0) break;
size += actual;
if (size < result.length) continue;
immutable newAlloc = size + sizeIncrement;
result = GC.realloc(result.ptr, newAlloc, GC.BlkAttr.NO_SCAN)[0 .. newAlloc];
}

return result.length - size >= maxSlackMemoryAllowed
? GC.realloc(result.ptr, size, GC.BlkAttr.NO_SCAN)[0 .. size]
: result[0 .. size];
}

version (Windows) void[] read(in char[] name, size_t upTo = size_t.max) @safe
{
import std.algorithm : min;
import std.array : uninitializedArray;
static trustedRef(T)(ref T buf) @trusted
{
return &buf;
}
version(Windows)
{
static trustedCreateFileW(in char[] fileName, DWORD dwDesiredAccess, DWORD dwShareMode,
SECURITY_ATTRIBUTES *lpSecurityAttributes, DWORD dwCreationDisposition,
DWORD dwFlagsAndAttributes, HANDLE hTemplateFile) @trusted
{
return CreateFileW(fileName.tempCStringW(), dwDesiredAccess, dwShareMode,
lpSecurityAttributes, dwCreationDisposition,
dwFlagsAndAttributes, hTemplateFile);

}
static trustedCloseHandle(HANDLE hObject) @trusted
{
return CloseHandle(hObject);
}
static trustedGetFileSize(HANDLE hFile, DWORD *lpFileSizeHigh) @trusted
{
return GetFileSize(hFile, lpFileSizeHigh);
}
static trustedReadFile(HANDLE hFile, void *lpBuffer, DWORD nNumberOfBytesToRead,
DWORD *lpNumberOfBytesRead, OVERLAPPED *lpOverlapped) @trusted
{
return ReadFile(hFile, lpBuffer, nNumberOfBytesToRead,
lpNumberOfBytesRead, lpOverlapped);
}

alias defaults =
TypeTuple!(GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE, (SECURITY_ATTRIBUTES*).init,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN,
HANDLE.init);
auto h = trustedCreateFileW(name, defaults);
static trustedCreateFileW(in char[] fileName, DWORD dwDesiredAccess, DWORD dwShareMode,
SECURITY_ATTRIBUTES *lpSecurityAttributes, DWORD dwCreationDisposition,
DWORD dwFlagsAndAttributes, HANDLE hTemplateFile) @trusted
{
return CreateFileW(fileName.tempCStringW(), dwDesiredAccess, dwShareMode,
lpSecurityAttributes, dwCreationDisposition,
dwFlagsAndAttributes, hTemplateFile);

cenforce(h != INVALID_HANDLE_VALUE, name);
scope(exit) cenforce(trustedCloseHandle(h), name);
auto size = trustedGetFileSize(h, null);
cenforce(size != INVALID_FILE_SIZE, name);
size = min(upTo, size);
auto buf = uninitializedArray!(ubyte[])(size);
scope(failure) delete buf;

DWORD numread = void;
cenforce(trustedReadFile(h,buf.ptr, size, trustedRef(numread), null) != 0
&& numread == size, name);
return buf[0 .. size];
}
else version(Posix)
static trustedCloseHandle(HANDLE hObject) @trusted
{
import core.memory;
// A few internal configuration parameters {
enum size_t
minInitialAlloc = 1024 * 4,
maxInitialAlloc = size_t.max / 2,
sizeIncrement = 1024 * 16,
maxSlackMemoryAllowed = 1024;
// }

static trustedOpen(in char[] path, int oflag) @trusted
{
return core.sys.posix.fcntl.open(path.tempCString(), oflag);
}
static trustedFstat(int path, stat_t* buf) @trusted
{
return fstat(path, buf);
}
static trustedRead(int fildes, void* buf, size_t nbyte) @trusted
{
return core.sys.posix.unistd.read(fildes, buf, nbyte);
}
static trustedRealloc(void* p, size_t sz, uint ba = 0, const TypeInfo ti = null) @trusted
{
return GC.realloc(p, sz, ba, ti);
}
static trustedPtrAdd(void[] buf, size_t s) @trusted
{
return buf.ptr+s;
}
static trustedPtrSlicing(void* ptr, size_t lb, size_t ub) @trusted
{
return ptr[lb..ub];
}

immutable fd = trustedOpen(name,
core.sys.posix.fcntl.O_RDONLY);
cenforce(fd != -1, name);
scope(exit) core.sys.posix.unistd.close(fd);

stat_t statbuf = void;
cenforce(trustedFstat(fd, trustedRef(statbuf)) == 0, name);
return CloseHandle(hObject);
}
static trustedGetFileSize(HANDLE hFile, DWORD *lpFileSizeHigh) @trusted
{
return GetFileSize(hFile, lpFileSizeHigh);
}
static trustedReadFile(HANDLE hFile, void *lpBuffer, DWORD nNumberOfBytesToRead,
DWORD *lpNumberOfBytesRead, OVERLAPPED *lpOverlapped) @trusted
{
return ReadFile(hFile, lpBuffer, nNumberOfBytesToRead,
lpNumberOfBytesRead, lpOverlapped);
}

immutable initialAlloc = to!size_t(statbuf.st_size
? min(statbuf.st_size + 1, maxInitialAlloc)
: minInitialAlloc);
void[] result = uninitializedArray!(ubyte[])(initialAlloc);
scope(failure) delete result;
size_t size = 0;
alias defaults =
TypeTuple!(GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE, (SECURITY_ATTRIBUTES*).init,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN,
HANDLE.init);
auto h = trustedCreateFileW(name, defaults);

for (;;)
{
immutable actual = trustedRead(fd, trustedPtrAdd(result, size),
min(result.length, upTo) - size);
cenforce(actual != -1, name);
if (actual == 0) break;
size += actual;
if (size < result.length) continue;
immutable newAlloc = size + sizeIncrement;
result = trustedPtrSlicing(trustedRealloc(result.ptr, newAlloc, GC.BlkAttr.NO_SCAN),
0, newAlloc);
}
cenforce(h != INVALID_HANDLE_VALUE, name);
scope(exit) cenforce(trustedCloseHandle(h), name);
auto size = trustedGetFileSize(h, null);
cenforce(size != INVALID_FILE_SIZE, name);
size = min(upTo, size);
auto buf = uninitializedArray!(ubyte[])(size);
scope(failure) delete buf;

return result.length - size >= maxSlackMemoryAllowed
? trustedPtrSlicing(trustedRealloc(result.ptr, size, GC.BlkAttr.NO_SCAN), 0, size)
: result[0 .. size];
}
DWORD numread = void;
cenforce(trustedReadFile(h,buf.ptr, size, trustedRef(numread), null) != 0
&& numread == size, name);
return buf[0 .. size];
}

@safe unittest
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