fd: new abstraction

src/fs/fd.c

@@ -0,0 +1,123 @@
+#include <kernel/fd.h>
+#include <arch/spinlock.h>
+#include <stdbool.h>
+#include <kernel/alloc.h>
+
+// XXX limit the max fd number
+
+int fd_release(fd_t* fd){	
+	spinlock_release(&fd->lock);
+	return 0;
+}
+
+int fd_access(fdtable_t* fdtable, fd_t** fd, int ifd){
+	spinlock_acquire(&fdtable->lock);
+	
+	if(ifd >= fdtable->fdcount || fdtable->fd[ifd] == NULL){
+		spinlock_release(&fdtable->lock);
+		return EBADF;
+	}
+
+	*fd = fdtable->fd[ifd];
+	fd_t* efd = *fd;
+	spinlock_acquire(&efd->lock);
+	spinlock_release(&fdtable->lock);
+
+	return 0;
+
+}
+
+int fd_alloc(fdtable_t* fdtable, fd_t** fd, int* ifd){
+	spinlock_acquire(&fdtable->lock);
+	
+	// find fd to use
+	
+	bool ok = false;
+
+	for(uintmax_t i = fdtable->firstfreefd; i < fdtable->fdcount; ++i){
+		if(!fdtable->fd[i]){
+			fdtable->firstfreefd = i;
+			*ifd = i;
+			ok = true;
+			break;
+		}
+	}
+
+	// resize table
+
+	if(!ok){
+		
+		fd_t** tmp = realloc(fdtable->fd, sizeof(fd_t*)*(fdtable->fdcount + 1));
+		
+		if(!tmp){
+			spinlock_release(&fdtable->lock);
+			return ENOMEM;
+		}	
+
+		fdtable->fd = tmp;
+		*ifd = fdtable->fdcount;
+		++fdtable->fdcount;
+		
+	}
+	
+	fd_t* tmp = alloc(sizeof(fd_t));
+	
+	if(!tmp){
+		spinlock_release(&fdtable->lock);
+		return ENOMEM;
+	}	
+
+	spinlock_acquire(&tmp->lock);
+	tmp->refcount = 1;
+
+
+	fdtable->fd[*ifd] = tmp;
+
+	spinlock_release(&fdtable->lock);
+
+	*fd = tmp;
+
+	return 0;
+
+}
+
+int fd_free(fdtable_t* fdtable, int ifd){
+	spinlock_acquire(&fdtable->lock);
+	
+	if(ifd >= fdtable->fdcount || fdtable->fd[ifd] == NULL){
+		spinlock_release(&fdtable->lock);
+		return EBADF;
+	}
+
+	fd_t* fd = fdtable->fd[ifd];
+	spinlock_acquire(&fd->lock);
+	
+	if(--fd->refcount > 0){
+		spinlock_release(&fd->lock);
+		spinlock_release(&fdtable->lock);
+		return 0;
+	}
+
+	fdtable->fd[ifd] = NULL;
+	
+	spinlock_release(&fdtable->lock);
+	
+	int err = vfs_close(fd->node);
+
+	free(fd);
+
+	return err;
+	
+}
+
+int fd_tableinit(fdtable_t* fdtable){
+	
+	fdtable->fd = alloc(sizeof(fd_t*)*3);
+
+	if(!fdtable->fd) return ENOMEM;
+
+	fdtable->fdcount = 3;
+	
+	return 0;
+
+}

src/include/kernel/fd.h

@@ -29,14 +29,29 @@
 #define O_RSYNC 04010000
 #define O_TMPFILE 020000000
 
-
+#include <stdint.h>
+#include <stddef.h>
 
 typedef struct {
+	uintmax_t refcount;
         vnode_t* node;
         off_t offset;
         int flags;
 	int lock;
+	mode_t mode;
 } fd_t;
 
+typedef struct {
+	int lock;
+	size_t fdcount;
+	uintmax_t firstfreefd;
+	fd_t** fd;
+} fdtable_t; 
+
+int fd_alloc(fdtable_t* fdtable, fd_t** fd, int* ifd);
+int fd_free(fdtable_t* fdtable, int ifd);
+int fd_access(fdtable_t* fdtable, fd_t** fd, int ifd);
+int fd_release(fd_t* fd);
+int fd_tableinit(fdtable_t* fdtable);
 
 #endif

src/include/kernel/sched.h

@@ -46,10 +46,7 @@ typedef struct _proc_t{
 	pid_t pid;
 	gid_t gid;
 	uid_t uid;
-	fd_t* fds;
-	int fdlock;
-	size_t fdcount;
-	off_t  firstfreefd;
+	fdtable_t fdtable; 
 	thread_t** threads;
 	size_t threadcount;
 	dirnode_t* root;

src/sys/sched/scheduler.c

@@ -10,7 +10,6 @@
 #include <kernel/elf.h>
 #include <arch/interrupt.h>
 
-#define PROC_START_FD_COUNT 3
 #define THREAD_QUANTUM 10000
 
 // queue 0: interrupt threads
@@ -34,18 +33,11 @@ static proc_t* allocproc(size_t threadcount){
 		return NULL;
 	}
 
-	proc->fds = alloc(sizeof(fd_t) * PROC_START_FD_COUNT);
-
-	if(!proc->fds){
+	if(fd_tableinit(&proc->fdtable)){
 		free(proc->threads);
 		free(proc);
 		return NULL;
 	}
-
-	proc->fdcount = PROC_START_FD_COUNT;
-	proc->firstfreefd = PROC_START_FD_COUNT;
-
-
 	
 	return proc;
 	
@@ -362,11 +354,15 @@ void sched_runinit(){
 
 	proc->root = vfs_root();
 	proc->cwd  = vfs_root();
-	proc->pid  = 1;
+	proc->pid  = 1;	
 
-	fd_t* stdinfd = &proc->fds[0];
-	fd_t* stdoutfd = &proc->fds[1];
-	fd_t* stderrfd = &proc->fds[2];
+	int tmp;
+
+	fd_t *stdinfd, *stdoutfd, *stderrfd;
+
+	fd_alloc(&proc->fdtable, &stdinfd, &tmp);
+	fd_alloc(&proc->fdtable, &stdoutfd, &tmp);
+	fd_alloc(&proc->fdtable, &stderrfd, &tmp);
 	
 	#define CONSOLE_PATH "dev/console"
 
@@ -417,6 +413,10 @@ void sched_runinit(){
 
 	arch_regs_setupuser(thread->regs, entry, stack, true);
 
+	fd_release(stdinfd);
+	fd_release(stdoutfd);
+	fd_release(stderrfd);
+
 	timer_add(&arch_getcls()->schedreq, THREAD_QUANTUM, true);
 	
 	switch_thread(thread);

src/sys/syscalls/close.c

@@ -6,40 +6,17 @@
 
 syscallret syscall_close(int ifd){
         syscallret retv;
-        retv.ret = -1;
+        retv.ret = 0;
+	retv.errno = 0;
 
         proc_t* proc = arch_getcls()->thread->proc;
 
-        fd_t* fd = proc->fds + ifd;
+	int err = fd_free(&proc->fdtable, ifd);
 
-        spinlock_acquire(&proc->fdlock);
-
-        if(proc->fdcount <= ifd || fd->node == NULL || (fd->flags & FD_FLAGS_READ) == 0){
-                spinlock_release(&proc->fdlock);
-                retv.errno = EBADF;
-                return retv;
-        }
-
-        spinlock_acquire(&fd->lock);
-        spinlock_release(&proc->fdlock);
-	
-	int ret = vfs_close(fd->node);
-	
-	if(ret){
-		retv.errno = ret;
-		goto _ret;
+	if(err){
+		retv.errno = err;
+		retv.ret = -1;
 	}
 
-	// the fd table isn't resized on a close
-	// although that can be added if it becomes an issue
-	
-	fd->node = NULL;
-
-	retv.ret = 0;
-	retv.errno = 0;
-
-	_ret:
-
-	spinlock_release(&fd->lock);
 	return retv;
 }

src/sys/syscalls/fstat.c

@@ -17,22 +17,18 @@ syscallret syscall_fstat(int ifd, stat* st){
 
 	proc_t* proc = arch_getcls()->thread->proc;
 
-        fd_t* fd = proc->fds + ifd;
-
-        spinlock_acquire(&proc->fdlock);
-
-        if(proc->fdcount <= ifd || fd->node == NULL || (fd->flags & FD_FLAGS_READ) == 0){
-                spinlock_release(&proc->fdlock);
-                retv.errno = EBADF;
-                return retv;
-        }
-
-        spinlock_acquire(&fd->lock);
-        spinlock_release(&proc->fdlock);
+        fd_t* fd;
 	
+	int err = fd_access(&proc->fdtable, &fd, ifd);
+
+	if(err){
+		retv.errno = err;
+		return retv;
+	}
+
 	memcpy(st, &fd->node->st, sizeof(stat)); // XXX user memcpy
 	
-	spinlock_release(&fd->lock);
+	fd_release(fd);
 
 	retv.errno = 0;
 	retv.ret = 0;

src/sys/syscalls/isatty.c

@@ -12,26 +12,22 @@ syscallret syscall_isatty(int ifd){
 	
 	proc_t* proc = arch_getcls()->thread->proc;
 
-        fd_t* fd = proc->fds + ifd;
+        fd_t* fd;
+	
+	int ret = fd_access(&proc->fdtable, &fd, ifd);
 
-        spinlock_acquire(&proc->fdlock);
-        
-	if(proc->fdcount <= ifd || fd->node == NULL){
-                spinlock_release(&proc->fdlock);
-                retv.errno = EBADF;
-                return retv;
-        }
+	if(ret){
+		retv.errno = ret;
+		return retv;
+	}
 
-        spinlock_acquire(&fd->lock);
-        spinlock_release(&proc->fdlock);
-
-	int ret = vfs_isatty(fd->node);
+	ret = vfs_isatty(fd->node);
 	
 	retv.errno = ret;
 
 	retv.ret = retv.errno == ENOTTY ? 0 : 1;
 
-	spinlock_release(&fd->lock);
+	fd_release(fd);
 
 	return retv;
 	

src/sys/syscalls/lseek.c

@@ -15,20 +15,16 @@ syscallret syscall_lseek(int ifd, off_t offset, int whence){
 
 	proc_t* proc = arch_getcls()->thread->proc;
 
-        fd_t* fd = proc->fds + ifd;
-
-        spinlock_acquire(&proc->fdlock);
-
-        if(proc->fdcount <= ifd || fd->node == NULL){
-                spinlock_release(&proc->fdlock);
-                retv.errno = EBADF;
-                return retv;
-        }
-
-        spinlock_acquire(&fd->lock);
-        spinlock_release(&proc->fdlock);
+        fd_t* fd;
 	
-	int type = GETTYPE(fd->node->st.st_mode);
+	int ret = fd_access(&proc->fdtable, &fd, ifd); 
+
+	if(ret){
+		retv.errno = ret;
+		return retv;
+	}
+
+	int type = GETTYPE(fd->mode);
 
 	if(type == TYPE_SOCKET || type == TYPE_FIFO){
 		retv.errno = ESPIPE;
@@ -71,7 +67,7 @@ syscallret syscall_lseek(int ifd, off_t offset, int whence){
 	retv.ret = newoffset;
 
 	_ret:
-	spinlock_release(&fd->lock);
+	fd_release(fd);
 	return retv;
 
 }

src/sys/syscalls/open.c

@@ -29,43 +29,17 @@ syscallret syscall_open(const char* pathname, int flags, mode_t mode){
 
 	proc_t* proc = arch_getcls()->thread->proc;
 	
-	spinlock_acquire(&proc->fdlock);
+	int ifd;
+	fd_t* fd;
 
-	fd_t* fd = NULL;
+	int err = fd_alloc(&proc->fdtable, &fd, &ifd);
 	
-	// find fd to use
-	
-	for(uintmax_t i = 0; i < proc->fdcount; ++i){
-		spinlock_acquire(&proc->fds[i].lock);
-		if(!proc->fds[i].node){
-			fd = &proc->fds[i].node;
-			break;
-		}
-		spinlock_release(&proc->fds[i].lock);
+	if(err){
+		retv.errno = err;
+		free(name);
+		return retv;	
 	}
 
-	// resize table
-
-	if(!fd){
-		
-		fd_t* tmp = realloc(proc->fds, sizeof(fd_t)*proc->fdcount + 1);
-		
-		if(!tmp){
-			spinlock_release(&proc->fdlock);
-			retv.errno = ENOMEM;
-			return retv;
-		}
-
-		proc->fds = tmp;
-		
-		fd = &proc->fds[proc->fdcount];
-		++proc->fdcount;
-		spinlock_acquire(&fd->lock);
-
-	}
-
-	spinlock_release(&proc->fdlock);
-	
 	fd->flags = flags + 1; // 1 is added to make O_RDONLY etc easier to lookup
 	fd->offset = 0;
 	
@@ -94,11 +68,11 @@ syscallret syscall_open(const char* pathname, int flags, mode_t mode){
 	
 	fd->node = file;
 
-	spinlock_release(&fd->lock);
-
+	fd_release(fd);
+	
 	free(name);	
 	retv.errno = 0;
-	retv.ret = ((uintptr_t)fd - (uintptr_t)proc->fds) / sizeof(fd_t);
+	retv.ret = ifd;
 
 	return retv;
 
@@ -106,7 +80,7 @@ syscallret syscall_open(const char* pathname, int flags, mode_t mode){
 
 	if(file)
 		vfs_close(file);
-	spinlock_release(&fd->lock);
+	fd_release(fd);
 	fd->node = NULL;
 	free(name);
 	return retv;

src/sys/syscalls/read.c

@@ -19,34 +19,29 @@ syscallret syscall_read(int ifd, void* buff, size_t count){
 
 	proc_t* proc = arch_getcls()->thread->proc;
 
-	fd_t* fd = proc->fds + ifd;
+	fd_t* fd;
 
-	spinlock_acquire(&proc->fdlock);
-
-	if(proc->fdcount <= ifd || fd->node == NULL || (fd->flags & FD_FLAGS_READ) == 0){
-		spinlock_release(&proc->fdlock);
-		retv.errno = EBADF;
+	int err = fd_access(&proc->fdtable, &fd, ifd); 
+	
+	if(err){
+		retv.errno = err;
 		return retv;
 	}
 
-	spinlock_acquire(&fd->lock);
-	spinlock_release(&proc->fdlock);
-
 	void* kbuff = alloc(count);
 
 	if(!kbuff){
-		spinlock_release(&fd->lock);
+		fd_release(fd);	
 		retv.errno = ENOMEM;
 		return retv;
 	}
 
-	int err;
 	size_t readc = vfs_read(&err, fd->node, kbuff, count, fd->offset);
 
 
 
-	if(err){	
-		spinlock_release(&fd->lock);
+	if(err){
+		fd_release(fd);	
 		free(kbuff);
 		retv.errno = err;
 		return retv;
@@ -54,7 +49,7 @@ syscallret syscall_read(int ifd, void* buff, size_t count){
 
 	fd->offset += readc;
 	
-	spinlock_release(&fd->lock);
+	fd_release(fd);	
 
 	memcpy(buff, kbuff, count); // XXX user version for safety
 

src/sys/syscalls/write.c

@@ -22,24 +22,20 @@ syscallret syscall_write(int ifd, void* buff, size_t count){
 
         proc_t* proc = arch_getcls()->thread->proc;
 
-        fd_t* fd = proc->fds + ifd;
+	fd_t* fd;
 
-        spinlock_acquire(&proc->fdlock);
+	int err = fd_access(&proc->fdtable, &fd, ifd);
 
-        if(proc->fdcount <= ifd || fd->node == NULL || (fd->flags & FD_FLAGS_WRITE) == 0){
-                spinlock_release(&proc->fdlock);
-                retv.errno = EBADF;
+	if(err){
+		retv.errno = err;
 		return retv;
-        }
-
-        spinlock_acquire(&fd->lock);
-        spinlock_release(&proc->fdlock);
+	}
 
         void* kbuff = alloc(count);
 
         if(!kbuff){
-                spinlock_release(&fd->lock);
-                retv.errno = ENOMEM;
+                fd_release(fd);
+		retv.errno = ENOMEM;
                 return retv;
         }
 	
@@ -48,7 +44,7 @@ syscallret syscall_write(int ifd, void* buff, size_t count){
 	if(fd->flags & O_APPEND)
 		fd->offset = fd->node->st.st_size;
 
-	int err;
+	
 	size_t writec = vfs_write(&err, fd->node, kbuff, count, fd->offset);
 
 
@@ -66,7 +62,7 @@ syscallret syscall_write(int ifd, void* buff, size_t count){
 	retv.ret = writec;
 
 	_ret:
-	spinlock_release(&fd->lock);
+	fd_release(fd);
 	free(kbuff);
 	return retv;
 }