Adds some missing functionality to Primus Lisp POSIX (#1489)

* Adds some missing functionality to Primus Lisp POSIX

- The thread local storage structure (on SysV x86-64) had some
additional data to set up
- Added `gets` and `strchrnul` to `stdio` and `string`, respectively

Co-authored-by: bmourad01 <bmourad@draper.com>

Author: bmourad01

plugins/primus_lisp/site-lisp/libc-init.lisp

@@ -24,19 +24,28 @@
   (set X1 0))
 
 
-(defun setup-stack-canary ()
+(defun setup-thread-local-storage ()
   (declare (context (abi "sysv"))
-           (global program:FS_BASE))
-  (set FS_BASE (- brk 0x28))
-  (memory-allocate brk (sizeof ptr_t))
-  (write-word ptr_t brk 0xDEADBEEFBEAFDEAD)
-  (+= brk (sizeof ptr_t)))
+           (global x86-64:FS_BASE))
+  (let ((tcb-size (+ (* 6 (sizeof ptr_t))
+                     (* 2 (sizeof int)))))
+    (set FS_BASE brk)
+    ;; tcbhead_t structure
+    (memory-allocate brk tcb-size 0)
+    (write-word ptr_t brk brk) ; tcb
+    (write-word ptr_t (+ brk 0x28) 0xDEADBEEFBEAFDEAD) ; stack_guard
+    ;; ptmalloc structure
+    (memory-allocate (- brk 0x28) (sizeof ptr_t) 0) ; arena
+    (memory-allocate (- brk 0x38) (sizeof ptr_t) 0) ; freelist
+    ;; misc
+    (memory-allocate (- brk 0x40) (sizeof int) 0) ; errno
+    (+= brk tcb-size)))
 
 (defun init (main argc argv auxv)
   "GNU libc initialization stub"
   (declare (external "__libc_start_main")
            (context (abi "sysv")))
-  (setup-stack-canary)
+  (setup-thread-local-storage)
   (exit-with (invoke-subroutine main argc argv)))
 
 (defun init (args on-exit main)

plugins/primus_lisp/site-lisp/stdio.lisp

@@ -130,6 +130,21 @@
       (memory-write (+ ptr (min n i)) 0:8)
       ptr))))
 
+(defun gets (ptr)
+  (declare (external "gets"))
+  (let ((str *standard-input*)
+        (i 0)
+        (continue true))
+    (while continue
+      (let ((c (fgetc str)))
+        (if (= c -1)
+            (set continue false)
+          (memory-write (+ ptr i) (cast char c))
+          (set continue (/= c 0xA))
+          (incr i))))
+    (memory-write (+ ptr i) 0:8)
+    ptr))
+
 
 (defun getchar ()
   (declare (external "getchar" "getchar_unlocked"))

plugins/primus_lisp/site-lisp/string.lisp

@@ -89,6 +89,10 @@
   (declare (external "strrchr" "rindex"))
   (memrchr p c (+ (strlen p) 1)))
 
+(defun strchrnul (p c)
+  (declare (external "strchrnul"))
+  (let ((p (strchr p c)))
+    (if p p (strchr p 0))))
 
 (defun strpbrk (str set)
   (declare (external "strpbrk"))