malloc: check if the requested memory is really available

cpu/cc2538/cc2538_linkerscript.ld

@@ -130,8 +130,10 @@ SECTIONS
         _estack = .;
     } > ram
 
+    /* heap section */
     . = ALIGN(4);
-    _end = . ;
+    _sheap = . ;
+    _eheap = ORIGIN(ram) + LENGTH(ram);
 
     .flashcca :
     {

cpu/cc2538/syscalls.c

@@ -42,8 +42,9 @@
 /**
  * manage the heap
  */
-extern uint32_t _end;                       /* address of last used memory cell */
-caddr_t heap_top = (caddr_t) &_end + 4;
+extern char _sheap;                 /* start of the heap */
+extern char _eheap;                 /* end of the heap */
+caddr_t heap_top = (caddr_t)&_sheap + 4;
 
 #ifndef MODULE_UART0
 /**
@@ -114,18 +115,23 @@ void _exit(int n)
  *
  * The current heap implementation is very rudimentary, it is only able to allocate
  * memory. But it does not
- * - check if the returned address is valid (no check if the memory very exists)
  * - have any means to free memory again
  *
- * TODO: check if the requested memory is really available
- *
  * @return [description]
  */
-caddr_t _sbrk_r(struct _reent *r, size_t incr)
+caddr_t _sbrk_r(struct _reent *r, ptrdiff_t incr)
 {
     unsigned int state = disableIRQ();
     caddr_t res = heap_top;
-    heap_top += incr;
+
+    if (((incr > 0) && ((heap_top + incr > &_eheap) || (heap_top + incr < res))) ||
+        ((incr < 0) && ((heap_top + incr < &_sheap) || (heap_top + incr > res)))) {
+        r->_errno = ENOMEM;
+        res = (void *) -1;
+    } else {
+        heap_top += incr;
+    }
+
     restoreIRQ(state);
     return res;
 }

cpu/nrf51822/nrf51822qfaa_linkerscript.ld

@@ -138,6 +138,8 @@ SECTIONS
         _estack = .;
     } > ram
 
+    /* heap section */
     . = ALIGN(4);
-    _end = . ;
+    _sheap = . ;
+    _eheap = ORIGIN(ram) + LENGTH(ram);
 }

cpu/nrf51822/syscalls.c

@@ -41,8 +41,9 @@
 /**
  * manage the heap
  */
-extern uint32_t _end;                       /* address of last used memory cell */
-caddr_t heap_top = (caddr_t)&_end + 4;
+extern char _sheap;                 /* start of the heap */
+extern char _eheap;                 /* end of the heap */
+caddr_t heap_top = (caddr_t)&_sheap + 4;
 
 /**
  * @brief use mutex for waiting on incoming UART chars
@@ -111,18 +112,24 @@ void _exit(int n)
  *
  * The current heap implementation is very rudimentary, it is only able to allocate
  * memory. But it does not
- * - check if the returned address is valid (no check if the memory very exists)
  * - have any means to free memory again
  *
- * TODO: check if the requested memory is really available
- *
  * @return [description]
  */
 caddr_t _sbrk_r(struct _reent *r, ptrdiff_t incr)
 {
     unsigned int state = disableIRQ();
     caddr_t res = heap_top;
-    heap_top += incr;
+
+    if (((incr > 0) && ((heap_top + incr > &_eheap) || (heap_top + incr < res))) ||
+        ((incr < 0) && ((heap_top + incr < &_sheap) || (heap_top + incr > res)))) {
+        r->_errno = ENOMEM;
+        res = (void *) -1;
+    }
+    else {
+        heap_top += incr;
+    }
+
     restoreIRQ(state);
     return res;
 }

cpu/sam3x8e/sam3x8e_linkerscript.ld

@@ -139,6 +139,8 @@ SECTIONS
         _estack = .;
     } > ram
 
+    /* heap section */
     . = ALIGN(4);
-    _end = . ;
-}
+    _sheap = . ;
+    _eheap = ORIGIN(ram) + LENGTH(ram);
+}

cpu/sam3x8e/syscalls.c

@@ -37,10 +37,9 @@
 /**
  * manage the heap
  */
-extern uint32_t _end;                       /* address of last used memory cell */
-caddr_t heap_top = (caddr_t)&_end + 4;
-
-
+extern char _sheap;                 /* start of the heap */
+extern char _eheap;                 /* end of the heap */
+caddr_t heap_top = (caddr_t)&_sheap + 4;
 /**
  * @brief Initialize NewLib, called by __libc_init_array() from the startup script
  */
@@ -77,18 +76,24 @@ void _exit(int n)
  *
  * The current heap implementation is very rudimentary, it is only able to allocate
  * memory. But it does not
- * - check if the returned address is valid (no check if the memory very exists)
  * - have any means to free memory again
  *
- * TODO: check if the requested memory is really available
- *
  * @return [description]
  */
 caddr_t _sbrk_r(struct _reent *r, ptrdiff_t incr)
 {
     unsigned int state = disableIRQ();
     caddr_t res = heap_top;
-    heap_top += incr;
+
+    if (((incr > 0) && ((heap_top + incr > &_eheap) || (heap_top + incr < res))) ||
+        ((incr < 0) && ((heap_top + incr < &_sheap) || (heap_top + incr > res)))) {
+        r->_errno = ENOMEM;
+        res = (void *) -1;
+    }
+    else {
+        heap_top += incr;
+    }
+
     restoreIRQ(state);
     return res;
 }

cpu/stm32f0/stm32f051r8_linkerscript.ld

@@ -137,6 +137,8 @@ SECTIONS
         _estack = .;
     } > ram
 
+    /* heap section */
     . = ALIGN(4);
-    _end = . ;
+    _sheap = . ;
+    _eheap = ORIGIN(ram) + LENGTH(ram);
 }

cpu/stm32f0/syscalls.c

@@ -43,8 +43,9 @@
 /**
  * manage the heap
  */
-extern uint32_t _end;                       /* address of last used memory cell */
-caddr_t heap_top = (caddr_t)&_end + 4;
+extern char _sheap;                 /* start of the heap */
+extern char _eheap;                 /* end of the heap */
+caddr_t heap_top = (caddr_t)&_sheap + 4;
 
 #ifndef MODULE_UART0
 /**
@@ -114,18 +115,24 @@ void _exit(int n)
  *
  * The current heap implementation is very rudimentary, it is only able to allocate
  * memory. But it does not
- * - check if the returned address is valid (no check if the memory very exists)
  * - have any means to free memory again
  *
- * TODO: check if the requested memory is really available
- *
  * @return [description]
  */
 caddr_t _sbrk_r(struct _reent *r, ptrdiff_t incr)
 {
     unsigned int state = disableIRQ();
     caddr_t res = heap_top;
-    heap_top += incr;
+
+    if (((incr > 0) && ((heap_top + incr > &_eheap) || (heap_top + incr < res))) ||
+        ((incr < 0) && ((heap_top + incr < &_sheap) || (heap_top + incr > res)))) {
+        r->_errno = ENOMEM;
+        res = (void *) -1;
+    }
+    else {
+        heap_top += incr;
+    }
+
     restoreIRQ(state);
     return res;
 }

cpu/stm32f1/stm32f103cb_linkerscript.ld

@@ -137,6 +137,8 @@ SECTIONS
         _estack = .;
     } > ram
 
+    /* heap section */
     . = ALIGN(4);
-    _end = . ;
+    _sheap = . ;
+    _eheap = ORIGIN(ram) + LENGTH(ram);
 }

cpu/stm32f1/stm32f103re_linkerscript.ld

@@ -137,6 +137,8 @@ SECTIONS
         _estack = .;
     } > ram
 
+    /* heap section */
     . = ALIGN(4);
-    _end = . ;
+    _sheap = . ;
+    _eheap = ORIGIN(ram) + LENGTH(ram);
 }

cpu/stm32f1/syscalls.c

@@ -43,8 +43,9 @@
 /**
  * manage the heap
  */
-extern uint32_t _end;                       /* address of last used memory cell */
-caddr_t heap_top = (caddr_t)&_end + 4;
+extern char _sheap;                 /* start of the heap */
+extern char _eheap;                 /* end of the heap */
+caddr_t heap_top = (caddr_t)&_sheap + 4;
 
 #ifndef MODULE_UART0
 /**
@@ -114,18 +115,24 @@ void _exit(int n)
  *
  * The current heap implementation is very rudimentary, it is only able to allocate
  * memory. But it does not
- * - check if the returned address is valid (no check if the memory very exists)
  * - have any means to free memory again
  *
- * TODO: check if the requested memory is really available
- *
  * @return [description]
  */
 caddr_t _sbrk_r(struct _reent *r, ptrdiff_t incr)
 {
     unsigned int state = disableIRQ();
     caddr_t res = heap_top;
-    heap_top += incr;
+
+    if (((incr > 0) && ((heap_top + incr > &_eheap) || (heap_top + incr < res))) ||
+        ((incr < 0) && ((heap_top + incr < &_sheap) || (heap_top + incr > res)))) {
+        r->_errno = ENOMEM;
+        res = (void *) -1;
+    }
+    else {
+        heap_top += incr;
+    }
+
     restoreIRQ(state);
     return res;
 }

cpu/stm32f3/stm32f303vc_linkerscript.ld

@@ -138,6 +138,8 @@ SECTIONS
         _estack = .;
     } > ram
 
+    /* heap section */
     . = ALIGN(4);
-    _end = . ;
+    _sheap = . ;
+    _eheap = ORIGIN(ram) + LENGTH(ram);
 }

cpu/stm32f3/syscalls.c

@@ -44,8 +44,9 @@
 /**
  * @brief manage the heap
  */
-extern uint32_t _end;                       /* address of last used memory cell */
-caddr_t heap_top = (caddr_t)&_end + 4;
+extern char _sheap;                 /* start of the heap */
+extern char _eheap;                 /* end of the heap */
+caddr_t heap_top = (caddr_t)&_sheap + 4;
 
 #ifndef MODULE_UART0
 /**
@@ -114,18 +115,24 @@ void _exit(int n)
  *
  * The current heap implementation is very rudimentary, it is only able to allocate
  * memory. But it does not
- * - check if the returned address is valid (no check if the memory very exists)
  * - have any means to free memory again
  *
- * TODO: check if the requested memory is really available
- *
  * @return [description]
  */
 caddr_t _sbrk_r(struct _reent *r, ptrdiff_t incr)
 {
     unsigned int state = disableIRQ();
     caddr_t res = heap_top;
-    heap_top += incr;
+
+    if (((incr > 0) && ((heap_top + incr > &_eheap) || (heap_top + incr < res))) ||
+        ((incr < 0) && ((heap_top + incr < &_sheap) || (heap_top + incr > res)))) {
+        r->_errno = ENOMEM;
+        res = (void *) -1;
+    }
+    else {
+        heap_top += incr;
+    }
+
     restoreIRQ(state);
     return res;
 }

cpu/stm32f4/stm32f407vg_linkerscript.ld

@@ -139,6 +139,8 @@ SECTIONS
         _estack = .;
     } > ram
 
+    /* heap section */
     . = ALIGN(4);
-    _end = . ;
+    _sheap = . ;
+    _eheap = ORIGIN(ram) + LENGTH(ram);
 }

cpu/stm32f4/stm32f415rg_linkerscript.ld

@@ -139,6 +139,8 @@ SECTIONS
         _estack = .;
     } > ram
 
+    /* heap section */
     . = ALIGN(4);
-    _end = . ;
+    _sheap = . ;
+    _eheap = ORIGIN(ram) + LENGTH(ram);
 }

cpu/stm32f4/syscalls.c

@@ -43,8 +43,9 @@
 /**
  * manage the heap
  */
-extern uint32_t _end;                       /* address of last used memory cell */
-caddr_t heap_top = (caddr_t)&_end + 4;
+extern char _sheap;                 /* start of the heap */
+extern char _eheap;                 /* end of the heap */
+caddr_t heap_top = (caddr_t)&_sheap + 4;
 
 #ifndef MODULE_UART0
 /**
@@ -114,18 +115,24 @@ void _exit(int n)
  *
  * The current heap implementation is very rudimentary, it is only able to allocate
  * memory. But it does not
- * - check if the returned address is valid (no check if the memory very exists)
  * - have any means to free memory again
  *
- * TODO: check if the requested memory is really available
- *
  * @return [description]
  */
 caddr_t _sbrk_r(struct _reent *r, ptrdiff_t incr)
 {
     unsigned int state = disableIRQ();
     caddr_t res = heap_top;
-    heap_top += incr;
+
+    if (((incr > 0) && ((heap_top + incr > &_eheap) || (heap_top + incr < res))) ||
+        ((incr < 0) && ((heap_top + incr < &_sheap) || (heap_top + incr > res)))) {
+        r->_errno = ENOMEM;
+        res = (void *) -1;
+    }
+    else {
+        heap_top += incr;
+    }
+
     restoreIRQ(state);
     return res;
 }