9os

commit b0f359791a7e87e08f84505af359dbabbac58018
parent 2530b27878b32447a48cd62f914762f3400521c6
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Sun, 25 Oct 2020 20:54:16 +0100

os9: Fix allocb() and alloc()

Change-Id: I736335207f7cbcf62c7779836cb94618e9b15594

Diffstat:
M
include/os9/os9.h
 | 
3
---
M
src/os9/alloc.c
 | 
44
++++++++++++++++++++++++++++----------------
M
src/os9/hosted/main.c
 | 
2
--

3 files changed, 28 insertions(+), 21 deletions(-)
diff --git a/include/os9/os9.h b/include/os9/os9.h
@@ -20,9 +20,6 @@
 #define NR_MPOINTS 4
 #define NR_CHANS  20
 
-#define NR_BUFFERS 512
-#define HEAPSIZ (4 * PAGESIZE)
-
 #define KiB 1024u
 #define MiB (1024u * KiB)
 #define GiB (1024ul * MiB)
diff --git a/src/os9/alloc.c b/src/os9/alloc.c
@@ -2,28 +2,37 @@
 
 #include <string.h>
 
+#ifndef NR_BUFFERS
+#define NR_BUFFERS 512
+#endif
+
+#ifndef HEAPSIZ
+#define HEAPSIZ 4
+#endif
+
 union bucket {
 	long long ll;
 	uintptr_t up;
 };
 
-extern char buffertab[NR_BUFFERS][PAGESIZE];
+char buffertab[NR_BUFFERS][PAGESIZE];
 
 void *
 allocb(int n)
 {
-	void *addr;
+	void *addr = NULL;
 	static unsigned long npages;
 	static mutex_t m;
 
 	lock(&m);
-	if (npages + n>= NR_BUFFERS)
-		panic("out of memory");
+	if (n >= NR_BUFFERS - npages)
+		goto end;
 	addr= buffertab[npages];
 	npages += n;
+end:
 	unlock(&m);
 
-	return memset(addr, 0, PAGESIZE);
+	return addr;
 }
 
 void *
@@ -31,27 +40,30 @@ alloc(size_t size)
 {
 	static int lockalloc;
 	size_t n;
-	union bucket  *bp;
-	static union bucket  *base, *heap;
+	static size_t used;
+	static union bucket *heap;
 	static mutex_t m;
+	union bucket  *bp = NULL;
 
+	lock(&m);
 	if (size == 0) {
 		lockalloc = 1;
-		return NULL;
+		goto end;
 	}
 
 	if (lockalloc)
-		panic("alloc with lock");
+		goto end;
 
-	lock(&m);
-	if (!base)
-		base = heap = allocb(HEAPSIZ/ PAGESIZE);
+	if (!heap)
+		heap = allocb(HEAPSIZ);
 
 	n = (size-1) / sizeof(union bucket) + 1;
-	bp = base;
-	if (&bp[size] > &heap[HEAPSIZ])
-		panic("out of memory");
-	base += n;
+	size = n * sizeof(union bucket);
+	if (used > SIZE_MAX - size)
+		goto end;
+	bp = heap + used;
+	used += size;
+end:
 	unlock(&m);
 
 	return bp;
diff --git a/src/os9/hosted/main.c b/src/os9/hosted/main.c
@@ -11,8 +11,6 @@
 noreturn void longjmp(jmp_buf env, int val);
 
 Chan *console;
-char buffertab[NR_BUFFERS][PAGESIZE];
-
 Mach mach;
 
 int