sortix-mirror/kernel/descriptor.cpp
2023-04-06 23:26:10 +02:00

1202 lines
34 KiB
C++

/*
* Copyright (c) 2012-2017, 2021 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* descriptor.cpp
* A file descriptor.
*/
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <assert.h>
#include <errno.h>
#include <fsmarshall-msg.h>
#include <limits.h>
#include <stdint.h>
#include <string.h>
#include <sortix/dirent.h>
#include <sortix/fcntl.h>
#ifndef IOV_MAX
#include <sortix/limits.h>
#endif
#include <sortix/mount.h>
#include <sortix/seek.h>
#include <sortix/stat.h>
#include <sortix/kernel/copy.h>
#include <sortix/kernel/descriptor.h>
#include <sortix/kernel/fsfunc.h>
#include <sortix/kernel/inode.h>
#include <sortix/kernel/ioctx.h>
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/kthread.h>
#include <sortix/kernel/process.h>
#include <sortix/kernel/refcount.h>
#include <sortix/kernel/string.h>
#include <sortix/kernel/vnode.h>
namespace Sortix {
// Flags for the various base modes to open a file in.
static const int ACCESS_FLAGS = O_READ | O_WRITE | O_EXEC | O_SEARCH;
// Flags that only make sense at open time.
static const int OPEN_FLAGS = O_CREATE | O_DIRECTORY | O_EXCL | O_TRUNC |
O_NOFOLLOW | O_SYMLINK_NOFOLLOW | O_NOCTTY |
O_TTY_INIT;
// Flags that only make sense for descriptors.
static const int DESCRIPTOR_FLAGS = O_APPEND | O_NONBLOCK;
// Let the ioctx_t force bits like O_NONBLOCK and otherwise use the dflags of
// the current file descriptor. This allows the caller to do non-blocking reads
// without calls to fcntl that may be racy with respect to other threads.
static int ContextFlags(int ctx_dflags, int desc_dflags)
{
return desc_dflags | (ctx_dflags & DESCRIPTOR_FLAGS);
}
int LinkInodeInDir(ioctx_t* ctx,
Ref<Descriptor> dir,
const char* name,
Ref<Inode> inode)
{
Ref<Vnode> vnode(new Vnode(inode, Ref<Vnode>(), 0, 0));
if ( !vnode )
return -1;
Ref<Descriptor> desc(new Descriptor(Ref<Vnode>(vnode), 0));
if ( !desc )
return -1;
return dir->link(ctx, name, desc);
}
Ref<Descriptor> OpenDirContainingPath(ioctx_t* ctx,
Ref<Descriptor> from,
const char* path,
char** final_ptr)
{
if ( !path[0] )
return errno = EINVAL, Ref<Descriptor>();
char* dirpath;
char* final;
if ( !SplitFinalElem(path, &dirpath, &final) )
return Ref<Descriptor>();
// TODO: Removing trailing slashes in final may not the right thing.
size_t final_length = strlen(final);
while ( final_length && final[final_length-1] == '/' )
final[--final_length] = 0;
// There is room for a single character as final is not the empty string.
if ( !final_length )
{
final[0] = '.';
final[1] = '\0';
}
if ( !dirpath[0] )
{
delete[] dirpath;
*final_ptr = final;
return from;
}
Ref<Descriptor> ret = from->open(ctx, dirpath, O_READ | O_DIRECTORY, 0);
delete[] dirpath;
if ( !ret )
return delete[] final, Ref<Descriptor>();
*final_ptr = final;
return ret;
}
size_t TruncateIOVec(struct iovec* iov, int iovcnt, off_t limit)
{
assert(0 <= iovcnt);
assert(0 <= limit);
off_t left = limit;
if ( (uintmax_t) SSIZE_MAX <= (uintmax_t) left )
left = SSIZE_MAX;
size_t requested = 0;
for ( int i = 0; i < iovcnt; i++ )
{
size_t request = iov[i].iov_len;
if ( __builtin_add_overflow(requested, request, &requested) )
requested = SIZE_MAX;
if ( left == 0 )
iov[i].iov_len = 0;
else if ( (uintmax_t) left < (uintmax_t) request )
{
iov[i].iov_len = left;
left = 0;
}
else
left -= request;
}
return requested;
}
// TODO: Add security checks.
Descriptor::Descriptor()
{
current_offset_lock = KTHREAD_MUTEX_INITIALIZER;
this->vnode = Ref<Vnode>(NULL);
this->ino = 0;
this->dev = 0;
this->type = 0;
this->dflags = 0;
checked_seekable = false;
seekable = false /* unused */;
current_offset = 0;
}
Descriptor::Descriptor(Ref<Vnode> vnode, int dflags)
{
current_offset_lock = KTHREAD_MUTEX_INITIALIZER;
this->vnode = Ref<Vnode>(NULL);
this->ino = 0;
this->dev = 0;
this->type = 0;
this->dflags = 0;
checked_seekable = false;
seekable = false /* unused */;
current_offset = 0;
LateConstruct(vnode, dflags);
}
void Descriptor::LateConstruct(Ref<Vnode> vnode, int dflags)
{
this->vnode = vnode;
this->ino = vnode->ino;
this->dev = vnode->dev;
this->type = vnode->type;
this->dflags = dflags;
}
Descriptor::~Descriptor()
{
}
bool Descriptor::SetFlags(int new_dflags)
{
// TODO: Hmm, there is race condition between changing the flags here and
// the code that uses the flags below. We could add a lock, but that
// would kinda prevent concurrency on the same file descriptor. Since
// the chances of this becoming a problem is rather slim (but could
// happen!), we'll do the unsafe thing for now. (See below also)
dflags = (dflags & ~DESCRIPTOR_FLAGS) | (new_dflags & DESCRIPTOR_FLAGS);
return true;
}
int Descriptor::GetFlags()
{
// TODO: The race condition also applies here if the variable can change.
return dflags;
}
Ref<Descriptor> Descriptor::Fork()
{
ScopedLock lock(&current_offset_lock);
Ref<Descriptor> ret(new Descriptor(vnode, dflags));
if ( !ret )
return Ref<Descriptor>();
ret->current_offset = current_offset;
ret->checked_seekable = checked_seekable;
ret->seekable = seekable;
return ret;
}
bool Descriptor::IsSeekable()
{
if ( S_ISCHR(type) )
return false;
ScopedLock lock(&current_offset_lock);
if ( !checked_seekable )
{
int saved_errno = errno;
ioctx_t ctx; SetupKernelIOCtx(&ctx);
seekable = S_ISDIR(vnode->type) || 0 <= vnode->lseek(&ctx, 0, SEEK_END);
checked_seekable = true;
errno = saved_errno;
}
return seekable;
}
bool Descriptor::pass()
{
return vnode->pass();
}
void Descriptor::unpass()
{
vnode->unpass();
}
int Descriptor::sync(ioctx_t* ctx)
{
// TODO: Possible denial-of-service attack if someone opens the file without
// that much rights and just syncs it a whole lot and slows down the
// system as a whole.
return vnode->sync(ctx);
}
int Descriptor::stat(ioctx_t* ctx, struct stat* st)
{
// TODO: Possible information leak if not O_READ | O_WRITE and the caller
// is told about the file size.
return vnode->stat(ctx, st);
}
int Descriptor::statvfs(ioctx_t* ctx, struct statvfs* stvfs)
{
// TODO: Possible information leak if not O_READ | O_WRITE and the caller
// is told about the file size.
return vnode->statvfs(ctx, stvfs);
}
int Descriptor::chmod(ioctx_t* ctx, mode_t mode)
{
// TODO: Regardless of dflags, check if the user/group can chmod.
return vnode->chmod(ctx, mode);
}
int Descriptor::chown(ioctx_t* ctx, uid_t owner, gid_t group)
{
// TODO: Regardless of dflags, check if the user/group can chown.
return vnode->chown(ctx, owner, group);
}
int Descriptor::truncate(ioctx_t* ctx, off_t length)
{
if ( length < 0 )
return errno = EINVAL, -1;
if ( !(dflags & O_WRITE) )
return errno = EBADF, -1;
return vnode->truncate(ctx, length);
}
off_t Descriptor::lseek(ioctx_t* ctx, off_t offset, int whence)
{
if ( S_ISCHR(type) )
{
if ( whence != SEEK_SET && whence != SEEK_CUR && whence != SEEK_END )
return errno = EINVAL, -1;
return 0;
}
if ( !IsSeekable() )
return errno = ESPIPE, -1;
ScopedLock lock(&current_offset_lock);
// TODO: Possible information leak to let someone without O_READ | O_WRITE
// seek the file and get information about data holes.
off_t reloff;
if ( whence == SEEK_SET )
reloff = 0;
else if ( whence == SEEK_CUR )
reloff = current_offset;
else if ( whence == SEEK_END )
{
if ( (reloff = vnode->lseek(ctx, 0, SEEK_END)) < 0 )
return -1;
}
else
return errno = EINVAL, -1;
off_t new_offset;
if ( __builtin_add_overflow(reloff, offset, &new_offset) )
return errno = EOVERFLOW, -1;
if ( new_offset < 0 )
return errno = EINVAL, -1;
return current_offset = new_offset;
}
ssize_t Descriptor::read(ioctx_t* ctx, uint8_t* buf, size_t count)
{
if ( !(dflags & O_READ) )
return errno = EBADF, -1;
if ( SIZE_MAX < count )
count = SSIZE_MAX;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
ssize_t result;
if ( !IsSeekable() )
result = vnode->read(ctx, buf, count);
else
{
ScopedLock lock(&current_offset_lock);
off_t available = OFF_MAX - current_offset;
if ( (uintmax_t) available < (uintmax_t) count )
count = available;
result = vnode->pread(ctx, buf, count, current_offset);
if ( 0 < result &&
__builtin_add_overflow(current_offset, result, &current_offset) )
current_offset = OFF_MAX;
}
ctx->dflags = old_ctx_dflags;
return result;
}
ssize_t Descriptor::readv(ioctx_t* ctx, const struct iovec* iov_ptr, int iovcnt)
{
if ( !(dflags & O_READ) )
return errno = EBADF, -1;
if ( iovcnt < 0 || IOV_MAX < iovcnt )
return errno = EINVAL, -1;
struct iovec* iov = new struct iovec[iovcnt];
if ( !iov )
return -1;
size_t iov_size = sizeof(struct iovec) * iovcnt;
if ( !ctx->copy_from_src(iov, iov_ptr, iov_size) )
return delete[] iov, -1;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
ssize_t result = -1;
if ( !IsSeekable() )
{
if ( SSIZE_MAX < TruncateIOVec(iov, iovcnt, SSIZE_MAX) )
errno = EINVAL;
else
result = vnode->readv(ctx, iov, iovcnt);
}
else
{
ScopedLock lock(&current_offset_lock);
off_t available = OFF_MAX - current_offset;
if ( SSIZE_MAX < TruncateIOVec(iov, iovcnt, available) )
errno = EINVAL;
else
result = vnode->preadv(ctx, iov, iovcnt, current_offset);
if ( 0 < result &&
__builtin_add_overflow(current_offset, result, &current_offset) )
current_offset = OFF_MAX;
}
ctx->dflags = old_ctx_dflags;
delete[] iov;
return result;
}
ssize_t Descriptor::pread(ioctx_t* ctx, uint8_t* buf, size_t count, off_t off)
{
if ( S_ISCHR(type) )
return read(ctx, buf, count);
if ( !(dflags & O_READ) )
return errno = EBADF, -1;
if ( !IsSeekable() )
return errno = ESPIPE, -1;
if ( off < 0 )
return errno = EINVAL, -1;
if ( SSIZE_MAX < count )
count = SSIZE_MAX;
off_t available = OFF_MAX - off;
if ( (uintmax_t) available < (uintmax_t) count )
count = available;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
ssize_t result = vnode->pread(ctx, buf, count, off);
ctx->dflags = old_ctx_dflags;
return result;
}
ssize_t Descriptor::preadv(ioctx_t* ctx, const struct iovec* iov_ptr,
int iovcnt, off_t off)
{
if ( S_ISCHR(type) )
return readv(ctx, iov_ptr, iovcnt);
if ( !(dflags & O_READ) )
return errno = EBADF, -1;
if ( !IsSeekable() )
return errno = ESPIPE, -1;
if ( off < 0 || iovcnt < 0 || IOV_MAX < iovcnt )
return errno = EINVAL, -1;
struct iovec* iov = new struct iovec[iovcnt];
if ( !iov )
return -1;
size_t iov_size = sizeof(struct iovec) * iovcnt;
if ( !ctx->copy_from_src(iov, iov_ptr, iov_size) )
return delete[] iov, -1;
off_t available = OFF_MAX - off;
if ( SSIZE_MAX < TruncateIOVec(iov, iovcnt, available) )
return delete[] iov, errno = EINVAL, -1;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
ssize_t result = vnode->preadv(ctx, iov, iovcnt, off);
ctx->dflags = old_ctx_dflags;
delete[] iov;
return result;
}
ssize_t Descriptor::write(ioctx_t* ctx, const uint8_t* buf, size_t count)
{
if ( !(dflags & O_WRITE) )
return errno = EBADF, -1;
if ( SSIZE_MAX < count )
count = SSIZE_MAX;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
ssize_t result;
if ( !IsSeekable() )
result = vnode->write(ctx, buf, count);
else
{
ScopedLock lock(&current_offset_lock);
if ( ctx->dflags & O_APPEND )
{
off_t end = vnode->lseek(ctx, 0, SEEK_END);
if ( 0 <= end )
current_offset = end;
}
if ( current_offset == OFF_MAX && count )
{
errno = EFBIG;
result = -1;
}
else
{
off_t available = OFF_MAX - current_offset;
if ( (uintmax_t) available < (uintmax_t) count )
count = available;
result = vnode->pwrite(ctx, buf, count, current_offset);
if ( 0 < result &&
__builtin_add_overflow(current_offset, result,
&current_offset) )
current_offset = OFF_MAX;
}
}
ctx->dflags = old_ctx_dflags;
return result;
}
ssize_t Descriptor::writev(ioctx_t* ctx, const struct iovec* iov_ptr,
int iovcnt)
{
if ( !(dflags & O_WRITE) )
return errno = EBADF, -1;
if ( iovcnt < 0 || IOV_MAX < iovcnt )
return errno = EINVAL, -1;
struct iovec* iov = new struct iovec[iovcnt];
if ( !iov )
return -1;
size_t iov_size = sizeof(struct iovec) * iovcnt;
if ( !ctx->copy_from_src(iov, iov_ptr, iov_size) )
return delete[] iov, -1;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
ssize_t result = -1;
if ( !IsSeekable() )
{
if ( SSIZE_MAX < TruncateIOVec(iov, iovcnt, SSIZE_MAX) )
errno = EINVAL;
else
result = vnode->writev(ctx, iov, iovcnt);
}
else
{
ScopedLock lock(&current_offset_lock);
if ( ctx->dflags & O_APPEND )
{
off_t end = vnode->lseek(ctx, 0, SEEK_END);
if ( 0 <= end )
current_offset = end;
}
off_t available = OFF_MAX - current_offset;
size_t count = TruncateIOVec(iov, iovcnt, available);
if ( SSIZE_MAX < count )
errno = EINVAL;
else if ( current_offset == OFF_MAX && count )
errno = EFBIG;
else
{
result = vnode->pwritev(ctx, iov, iovcnt, current_offset);
if ( 0 < result &&
__builtin_add_overflow(current_offset, result,
&current_offset) )
current_offset = OFF_MAX;
}
}
ctx->dflags = old_ctx_dflags;
delete[] iov;
return result;
}
ssize_t Descriptor::pwrite(ioctx_t* ctx, const uint8_t* buf, size_t count,
off_t off)
{
if ( S_ISCHR(type) )
return write(ctx, buf, count);
if ( !(dflags & O_WRITE) )
return errno = EBADF, -1;
if ( !IsSeekable() )
return errno = ESPIPE, -1;
if ( off < 0 )
return errno = EINVAL, -1;
if ( off == OFF_MAX && count )
return errno = EFBIG, -1;
if ( SSIZE_MAX < count )
count = SSIZE_MAX;
off_t available = OFF_MAX - off;
if ( (uintmax_t) available < (uintmax_t) count )
count = available;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
ssize_t result = vnode->pwrite(ctx, buf, count, off);
ctx->dflags = old_ctx_dflags;
return result;
}
ssize_t Descriptor::pwritev(ioctx_t* ctx, const struct iovec* iov_ptr,
int iovcnt, off_t off)
{
if ( S_ISCHR(type) )
return writev(ctx, iov_ptr, iovcnt);
if ( !(dflags & O_WRITE) )
return errno = EBADF, -1;
if ( !IsSeekable() )
return errno = ESPIPE, -1;
if ( off < 0 || iovcnt < 0 || IOV_MAX < iovcnt )
return errno = EINVAL, -1;
struct iovec* iov = new struct iovec[iovcnt];
if ( !iov )
return -1;
size_t iov_size = sizeof(struct iovec) * iovcnt;
if ( !ctx->copy_from_src(iov, iov_ptr, iov_size) )
return delete[] iov, -1;
off_t available = OFF_MAX - off;
size_t count = TruncateIOVec(iov, iovcnt, available);
if ( SSIZE_MAX < count )
return delete[] iov, errno = EINVAL, -1;
if ( off == OFF_MAX && count != 0 )
return delete[] iov, errno = EFBIG, -1;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
ssize_t result = vnode->pwritev(ctx, iov, iovcnt, off);
ctx->dflags = old_ctx_dflags;
delete[] iov;
return result;
}
static inline bool valid_utimens_timespec(struct timespec ts)
{
return (0 <= ts.tv_nsec && ts.tv_nsec < 1000000000) ||
ts.tv_nsec == UTIME_NOW ||
ts.tv_nsec == UTIME_OMIT;
}
int Descriptor::utimens(ioctx_t* ctx, const struct timespec* user_times)
{
struct timespec times[2];
if ( !user_times )
{
times[0].tv_sec = 0;
times[0].tv_nsec = UTIME_NOW;
times[1].tv_sec = 0;
times[1].tv_nsec = UTIME_NOW;
}
else if ( !ctx->copy_from_src(&times, user_times, sizeof(times)) )
return -1;
if ( !valid_utimens_timespec(times[0]) ||
!valid_utimens_timespec(times[1]) )
return errno = EINVAL, -1;
// TODO: Regardless of dflags, check if the user/group can utimens.
return vnode->utimens(ctx, times);
}
int Descriptor::isatty(ioctx_t* ctx)
{
return vnode->isatty(ctx);
}
ssize_t Descriptor::readdirents(ioctx_t* ctx,
struct dirent* dirent,
size_t size)
{
// TODO: COMPATIBILITY HACK: Traditionally, you can open a directory with
// O_RDONLY and pass it to fdopendir and then use it, which doesn't
// set the needed O_SEARCH flag! I think some software even do it with
// write permissions! Currently, we just let you search the directory
// if you opened with any of the O_SEARCH, O_READ or O_WRITE flags.
// A better solution would be to make fdopendir try to add the
// O_SEARCH flag to the file descriptor. Or perhaps just recheck the
// permissions to search (execute) the directory manually every time,
// though that is less pure. Unfortunately, POSIX is pretty vague on
// how O_SEARCH should be interpreted and most existing Unix systems
// such as Linux doesn't even have that flag! And how about combining
// it with the O_EXEC flag - POSIX allows that and it makes sense
// because the execute bit on directories control search permission.
if ( !(dflags & (O_SEARCH | O_READ | O_WRITE)) )
return errno = EBADF, -1;
if ( SSIZE_MAX < size )
size = SSIZE_MAX;
if ( size < sizeof(*dirent) )
return errno = EINVAL, -1;
ScopedLock lock(&current_offset_lock);
if ( current_offset == OFF_MAX && size )
return 0;
ssize_t ret = vnode->readdirents(ctx, dirent, size, current_offset);
if ( 0 < ret &&
__builtin_add_overflow(current_offset, 1, &current_offset) )
current_offset = OFF_MAX;
return ret;
}
static bool IsSaneFlagModeCombination(int flags, mode_t /*mode*/)
{
// It doesn't make sense to pass O_CREATE or O_TRUNC when attempting to open
// a directory. We also reject O_TRUNC | O_DIRECTORY early to prevent
// opening a directory, attempting to truncate it, and then aborting with an
// error because a directory was opened.
if ( (flags & (O_CREATE | O_TRUNC)) && (flags & (O_DIRECTORY)) )
return false;
// POSIX: "The result of using O_TRUNC without either O_RDWR or
// O_WRONLY is undefined."
if ( (flags & O_TRUNC) && !(flags & O_WRITE) )
return false;
return true;
}
static bool IsLastPathElement(const char* elem)
{
while ( !(*elem == '/' || *elem == '\0') )
elem++;
while ( *elem == '/' )
elem++;
return *elem == '\0';
}
Ref<Descriptor> Descriptor::open(ioctx_t* ctx, const char* filename, int flags,
mode_t mode)
{
Process* process = CurrentProcess();
kthread_mutex_lock(&process->idlock);
mode &= ~process->umask;
kthread_mutex_unlock(&process->idlock);
if ( !filename[0] )
return errno = ENOENT, Ref<Descriptor>();
// Reject some non-sensical flag combinations early.
if ( !IsSaneFlagModeCombination(flags, mode) )
return errno = EINVAL, Ref<Descriptor>();
char* filename_mine = NULL;
size_t symlink_iteration = 0;
const size_t MAX_SYMLINK_ITERATION = 20;
Ref<Descriptor> desc(this);
while ( filename[0] )
{
// Reaching a slash in the path means that the caller intended what came
// before to be a directory, stop the open call if it isn't.
if ( filename[0] == '/' )
{
if ( !S_ISDIR(desc->type) )
return delete[] filename_mine, errno = ENOTDIR, Ref<Descriptor>();
filename++;
continue;
}
// Cut out the next path element from the input string.
size_t slashpos = strcspn(filename, "/");
char* elem = String::Substring(filename, 0, slashpos);
if ( !elem )
return delete[] filename_mine, Ref<Descriptor>();
// Decide how to open the next element in the path.
bool lastelem = IsLastPathElement(filename);
int open_flags = lastelem ? flags : O_READ | O_DIRECTORY;
mode_t open_mode = lastelem ? mode : 0;
// Open the next element in the path.
Ref<Descriptor> next = desc->open_elem(ctx, elem, open_flags, open_mode);
delete[] elem;
if ( !next )
return delete[] filename_mine, Ref<Descriptor>();
filename += slashpos;
bool want_the_symlink_itself = lastelem && (flags & O_SYMLINK_NOFOLLOW);
if ( S_ISLNK(next->type) && !want_the_symlink_itself )
{
if ( (flags & O_NOFOLLOW) && lastelem )
return delete[] filename_mine, errno = ELOOP, Ref<Descriptor>();
if ( symlink_iteration++ == MAX_SYMLINK_ITERATION )
return delete[] filename_mine, errno = ELOOP, Ref<Descriptor>();
ioctx_t kctx;
SetupKernelIOCtx(&kctx);
struct stat st;
if ( next->stat(&kctx, &st) < 0 )
return delete[] filename_mine, Ref<Descriptor>();
assert(0 <= st.st_size);
if ( (uintmax_t) SIZE_MAX <= (uintmax_t) st.st_size )
return delete[] filename_mine, Ref<Descriptor>();
size_t linkpath_length = (size_t) st.st_size;
char* linkpath = new char[linkpath_length + 1];
if ( !linkpath )
return delete[] filename_mine, Ref<Descriptor>();
ssize_t linkpath_ret = next->readlink(&kctx, linkpath, linkpath_length);
if ( linkpath_ret < 0 )
return delete[] linkpath, delete[] filename_mine, Ref<Descriptor>();
linkpath[linkpath_length] = '\0';
linkpath_length = strlen(linkpath);
if ( linkpath_length == 0 )
return delete[] linkpath, delete[] filename_mine,
errno = ENOENT, Ref<Descriptor>();
bool link_from_root = linkpath[0] == '/';
// Either filename is the empty string or starts with a slash.
size_t filename_length = strlen(filename);
// TODO: Avoid overflow here.
size_t new_filename_length = linkpath_length + filename_length;
char* new_filename = new char[new_filename_length + 1];
if ( !new_filename )
return delete[] linkpath, delete[] filename_mine,
errno = ENOENT, Ref<Descriptor>();
stpcpy(stpcpy(new_filename, linkpath), filename);
delete[] filename_mine;
filename = filename_mine = new_filename;
if ( link_from_root )
desc = CurrentProcess()->GetRoot();
continue;
}
desc = next;
}
delete[] filename_mine;
// Abort if the user tries to write to an existing directory.
if ( S_ISDIR(desc->type) )
{
if ( flags & (O_CREATE | O_TRUNC | O_WRITE) )
return errno = EISDIR, Ref<Descriptor>();
}
// Truncate the file if requested.
if ( (flags & O_TRUNC) && S_ISREG(desc->type) )
{
assert(flags & O_WRITE); // IsSaneFlagModeCombination
if ( desc->truncate(ctx, 0) < 0 )
return Ref<Descriptor>();
}
// Abort the open if the user wanted a directory but this wasn't.
if ( flags & O_DIRECTORY && !S_ISDIR(desc->type) )
return errno = ENOTDIR, Ref<Descriptor>();
// TODO: The new file descriptor may not be opened with the correct
// permissions in the below case!
// If the path only contains slashes, we'll get outselves back, be sure to
// get ourselves back.
return desc == this ? Fork() : desc;
}
Ref<Descriptor> Descriptor::open_elem(ioctx_t* ctx, const char* filename,
int flags, mode_t mode)
{
assert(!strchr(filename, '/'));
// Verify that at least one of the base access modes are being used.
if ( !(flags & ACCESS_FLAGS) )
return errno = EINVAL, Ref<Descriptor>();
// Filter away flags that only make sense for descriptors.
int retvnode_flags = flags & ~DESCRIPTOR_FLAGS;
Ref<Vnode> retvnode = vnode->open(ctx, filename, retvnode_flags, mode);
if ( !retvnode )
return Ref<Descriptor>();
// Filter away flags that only made sense at during the open call.
int ret_flags = flags & ~OPEN_FLAGS;
Ref<Descriptor> ret(new Descriptor(retvnode, ret_flags));
if ( !ret )
return Ref<Descriptor>();
return ret;
}
int Descriptor::mkdir(ioctx_t* ctx, const char* filename, mode_t mode)
{
Process* process = CurrentProcess();
kthread_mutex_lock(&process->idlock);
mode &= ~process->umask;
kthread_mutex_unlock(&process->idlock);
char* final;
Ref<Descriptor> dir = OpenDirContainingPath(ctx, Ref<Descriptor>(this),
filename, &final);
if ( !dir )
return -1;
int ret = dir->vnode->mkdir(ctx, final, mode);
delete[] final;
return ret;
}
int Descriptor::link(ioctx_t* ctx, const char* filename, Ref<Descriptor> node)
{
char* final;
Ref<Descriptor> dir = OpenDirContainingPath(ctx, Ref<Descriptor>(this),
filename, &final);
if ( !dir )
return -1;
int ret = dir->vnode->link(ctx, final, node->vnode);
delete[] final;
return ret;
}
int Descriptor::unlinkat(ioctx_t* ctx, const char* filename, int flags)
{
if ( flags & ~(AT_REMOVEFILE | AT_REMOVEDIR) )
return errno = EINVAL, -1;
if ( !(flags & (AT_REMOVEFILE | AT_REMOVEDIR)) )
flags |= AT_REMOVEFILE;
char* final;
Ref<Descriptor> dir = OpenDirContainingPath(ctx, Ref<Descriptor>(this),
filename, &final);
if ( !dir )
return -1;
int ret = -1;
if ( ret < 0 && (flags & AT_REMOVEFILE) )
ret = dir->vnode->unlink(ctx, final);
if ( ret < 0 && (flags & AT_REMOVEDIR) )
ret = dir->vnode->rmdir(ctx, final);
delete[] final;
return ret;
}
int Descriptor::symlink(ioctx_t* ctx, const char* oldname, const char* filename)
{
char* final;
Ref<Descriptor> dir = OpenDirContainingPath(ctx, Ref<Descriptor>(this),
filename, &final);
if ( !dir )
return -1;
int ret = dir->vnode->symlink(ctx, oldname, final);
delete[] final;
return ret;
}
int Descriptor::rename_here(ioctx_t* ctx, Ref<Descriptor> from,
const char* oldpath, const char* newpath)
{
char* olddir_elem;
char* newdir_elem;
Ref<Descriptor> olddir = OpenDirContainingPath(ctx, from, oldpath,
&olddir_elem);
if ( !olddir )
return -1;
Ref<Descriptor> newdir = OpenDirContainingPath(ctx, Ref<Descriptor>(this),
newpath, &newdir_elem);
if ( !newdir )
return delete[] olddir_elem, -1;
int ret = newdir->vnode->rename_here(ctx, olddir->vnode, olddir_elem,
newdir_elem);
delete[] newdir_elem;
delete[] olddir_elem;
return ret;
}
ssize_t Descriptor::readlink(ioctx_t* ctx, char* buf, size_t bufsize)
{
if ( !(dflags & O_READ) )
return errno = EBADF, -1;
if ( SSIZE_MAX < bufsize )
bufsize = SSIZE_MAX;
return vnode->readlink(ctx, buf, bufsize);
}
int Descriptor::tcgetwincurpos(ioctx_t* ctx, struct wincurpos* wcp)
{
return vnode->tcgetwincurpos(ctx, wcp);
}
int Descriptor::ioctl(ioctx_t* ctx, int cmd, uintptr_t arg)
{
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
int result = vnode->ioctl(ctx, cmd, arg);
ctx->dflags = old_ctx_dflags;
return result;
}
int Descriptor::tcsetpgrp(ioctx_t* ctx, pid_t pgid)
{
return vnode->tcsetpgrp(ctx, pgid);
}
pid_t Descriptor::tcgetpgrp(ioctx_t* ctx)
{
return vnode->tcgetpgrp(ctx);
}
int Descriptor::settermmode(ioctx_t* ctx, unsigned mode)
{
return vnode->settermmode(ctx, mode);
}
int Descriptor::gettermmode(ioctx_t* ctx, unsigned* mode)
{
return vnode->gettermmode(ctx, mode);
}
int Descriptor::poll(ioctx_t* ctx, PollNode* node)
{
// TODO: Perhaps deny polling against some kind of events if this
// descriptor's dflags would reject doing these operations?
return vnode->poll(ctx, node);
}
Ref<Descriptor> Descriptor::accept4(ioctx_t* ctx, uint8_t* addr,
size_t* addrlen, int flags)
{
if ( flags & ~(SOCK_NONBLOCK) )
return errno = EINVAL, Ref<Descriptor>();
int new_dflags = O_READ | O_WRITE;
if ( flags & SOCK_NONBLOCK )
new_dflags |= O_NONBLOCK;
flags &= ~(SOCK_NONBLOCK);
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
Ref<Vnode> retvnode = vnode->accept4(ctx, addr, addrlen, flags);
if ( !retvnode )
return Ref<Descriptor>();
ctx->dflags = old_ctx_dflags;
return Ref<Descriptor>(new Descriptor(retvnode, new_dflags));
}
int Descriptor::bind(ioctx_t* ctx, const uint8_t* addr, size_t addrlen)
{
return vnode->bind(ctx, addr, addrlen);
}
int Descriptor::connect(ioctx_t* ctx, const uint8_t* addr, size_t addrlen)
{
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
int result = vnode->connect(ctx, addr, addrlen);
ctx->dflags = old_ctx_dflags;
return result;
}
int Descriptor::listen(ioctx_t* ctx, int backlog)
{
return vnode->listen(ctx, backlog);
}
ssize_t Descriptor::recv(ioctx_t* ctx, uint8_t* buf, size_t count, int flags)
{
if ( SIZE_MAX < count )
count = SSIZE_MAX;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
if ( flags & MSG_DONTWAIT )
ctx->dflags |= O_NONBLOCK;
flags &= ~MSG_DONTWAIT;
ssize_t result = vnode->recv(ctx, buf, count, flags);
ctx->dflags = old_ctx_dflags;
return result;
}
ssize_t Descriptor::recvmsg(ioctx_t* ctx, struct msghdr* msg, int flags)
{
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
if ( flags & MSG_DONTWAIT )
ctx->dflags |= O_NONBLOCK;
flags &= ~MSG_DONTWAIT;
ssize_t result = vnode->recvmsg(ctx, msg, flags);
ctx->dflags = old_ctx_dflags;
return result;
}
ssize_t Descriptor::send(ioctx_t* ctx, const uint8_t* buf, size_t count, int flags)
{
if ( SIZE_MAX < count )
count = SSIZE_MAX;
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
if ( flags & MSG_DONTWAIT )
ctx->dflags |= O_NONBLOCK;
flags &= ~MSG_DONTWAIT;
ssize_t result = vnode->send(ctx, buf, count, flags);
ctx->dflags = old_ctx_dflags;
return result;
}
ssize_t Descriptor::sendmsg(ioctx_t* ctx, const struct msghdr* msg, int flags)
{
int old_ctx_dflags = ctx->dflags;
ctx->dflags = ContextFlags(old_ctx_dflags, dflags);
if ( flags & MSG_DONTWAIT )
ctx->dflags |= O_NONBLOCK;
flags &= ~MSG_DONTWAIT;
ssize_t result = vnode->sendmsg(ctx, msg, flags);
ctx->dflags = old_ctx_dflags;
return result;
}
int Descriptor::getsockopt(ioctx_t* ctx, int level, int option_name,
void* option_value, size_t* option_size_ptr)
{
return vnode->getsockopt(ctx, level, option_name, option_value, option_size_ptr);
}
int Descriptor::setsockopt(ioctx_t* ctx, int level, int option_name,
const void* option_value, size_t option_size)
{
return vnode->setsockopt(ctx, level, option_name, option_value, option_size);
}
ssize_t Descriptor::tcgetblob(ioctx_t* ctx, const char* name, void* buffer, size_t count)
{
if ( name && !name[0] )
name = NULL;
if ( SSIZE_MAX < count )
count = SSIZE_MAX;
return vnode->tcgetblob(ctx, name, buffer, count);
}
ssize_t Descriptor::tcsetblob(ioctx_t* ctx, const char* name, const void* buffer, size_t count)
{
if ( name && !name[0] )
name = NULL;
if ( SSIZE_MAX < count )
return errno = EFBIG, -1;
return vnode->tcsetblob(ctx, name, buffer, count);
}
int Descriptor::unmount(ioctx_t* ctx, const char* filename, int flags)
{
if ( flags & ~(UNMOUNT_FORCE | UNMOUNT_DETACH | UNMOUNT_NOFOLLOW) )
return errno = EINVAL, -1;
int subflags = flags & ~(UNMOUNT_NOFOLLOW);
char* final;
// TODO: This may follow a symlink when not supposed to!
Ref<Descriptor> dir =
OpenDirContainingPath(ctx, Ref<Descriptor>(this), filename, &final);
if ( !dir )
return -1;
if ( !(flags & UNMOUNT_NOFOLLOW) )
{
// TODO: Potentially follow a symlink here!
}
int ret = dir->vnode->unmount(ctx, final, subflags);
delete[] final;
return ret;
}
int Descriptor::fsm_fsbind(ioctx_t* ctx, Ref<Descriptor> target, int flags)
{
return vnode->fsm_fsbind(ctx, target->vnode, flags);
}
Ref<Descriptor> Descriptor::fsm_mount(ioctx_t* ctx,
const char* filename,
const struct stat* rootst,
int flags)
{
if ( flags & ~(FSM_MOUNT_NOFOLLOW | FSM_MOUNT_NONBLOCK) )
return errno = EINVAL, Ref<Descriptor>(NULL);
int result_dflags = O_READ | O_WRITE;
if ( flags & FSM_MOUNT_NOFOLLOW ) result_dflags |= O_NONBLOCK;
int subflags = flags & ~(FSM_MOUNT_NOFOLLOW | FSM_MOUNT_NONBLOCK);
char* final;
// TODO: This may follow a symlink when not supposed to!
Ref<Descriptor> dir =
OpenDirContainingPath(ctx, Ref<Descriptor>(this), filename, &final);
if ( !dir )
return errno = EINVAL, Ref<Descriptor>(NULL);
if ( !(flags & FSM_MOUNT_NOFOLLOW) )
{
// TODO: Potentially follow a symlink here!
}
Ref<Descriptor> result(new Descriptor());
if ( !result )
return Ref<Descriptor>(NULL);
Ref<Vnode> result_vnode = dir->vnode->fsm_mount(ctx, final, rootst, subflags);
delete[] final;
if ( !result_vnode )
return Ref<Descriptor>(NULL);
result->LateConstruct(result_vnode, result_dflags);
return result;
}
int Descriptor::tcdrain(ioctx_t* ctx)
{
return vnode->tcdrain(ctx);
}
int Descriptor::tcflow(ioctx_t* ctx, int action)
{
return vnode->tcflow(ctx, action);
}
int Descriptor::tcflush(ioctx_t* ctx, int queue_selector)
{
return vnode->tcflush(ctx, queue_selector);
}
int Descriptor::tcgetattr(ioctx_t* ctx, struct termios* tio)
{
return vnode->tcgetattr(ctx, tio);
}
pid_t Descriptor::tcgetsid(ioctx_t* ctx)
{
return vnode->tcgetsid(ctx);
}
int Descriptor::tcsendbreak(ioctx_t* ctx, int duration)
{
return vnode->tcsendbreak(ctx, duration);
}
int Descriptor::tcsetattr(ioctx_t* ctx, int actions, const struct termios* tio)
{
return vnode->tcsetattr(ctx, actions, tio);
}
int Descriptor::shutdown(ioctx_t* ctx, int how)
{
if ( how & ~(SHUT_RD | SHUT_WR) )
return errno = EINVAL, -1;
return vnode->shutdown(ctx, how);
}
int Descriptor::getpeername(ioctx_t* ctx, uint8_t* addr, size_t* addrsize)
{
return vnode->getpeername(ctx, addr, addrsize);
}
int Descriptor::getsockname(ioctx_t* ctx, uint8_t* addr, size_t* addrsize)
{
return vnode->getsockname(ctx, addr, addrsize);
}
} // namespace Sortix