lseek syscall

src/arch/x86_64/syscall.asm

@@ -7,6 +7,7 @@ extern syscall_arch_ctl
 extern syscall_gettid
 extern syscall_open
 extern syscall_read
+extern syscall_lseek
 func_count equ 6
 
 
@@ -17,6 +18,7 @@ func_table:
 	dq syscall_gettid
 	dq syscall_open
 	dq syscall_read
+	dq syscall_lseek
 section .text
 global asm_syscall_entry
 

src/sys/syscalls/lseek.c

@@ -0,0 +1,77 @@
+#include <kernel/syscalls.h>
+#include <arch/cls.h>
+#include <kernel/fd.h>
+#include <arch/spinlock.h>
+#include <sys/stat.h>
+
+#define SEEK_SET 0
+#define SEEK_CUR 1
+#define SEEK_END 2
+
+syscallret syscall_lseek(int ifd, off_t offset, int whence){
+
+	syscallret retv;
+        retv.ret = -1;
+
+	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);
+	
+	int type = GETTYPE(fd->node->st.st_mode);
+
+	if(type == TYPE_SOCKET || type == TYPE_FIFO){
+		retv.errno = ESPIPE;
+		goto _ret;
+	}
+
+	off_t newoffset = fd->offset;
+	size_t fsize = fd->node->st.st_size;
+
+	switch(whence){
+		case SEEK_SET:
+			if(offset < 0 || offset > fsize){
+				retv.errno = EINVAL;
+				goto _ret;
+			}
+			newoffset = offset;
+			break;
+		case SEEK_CUR:
+			newoffset += offset;
+			if(newoffset < 0 || newoffset > fsize){
+				retv.errno = EINVAL;
+				goto _ret;
+			}
+			
+			if(newoffset < offset){
+				retv.errno = EOVERFLOW;
+				goto _ret;
+			}
+			break;
+		case SEEK_END:
+			newoffset = fsize;
+			break;
+		default:
+			retv.errno = EINVAL;
+			goto _ret;
+	}
+	
+	fd->offset = newoffset;
+	retv.errno = 0;
+	retv.ret = newoffset;
+
+	_ret:
+	spinlock_release(&fd->lock);
+	return retv;
+
+}