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libc: newlib: make sbrk() thread-safe

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Concurrent use of this function could lead to corruption.
Use a sys_sem to synchronize access.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2019-07-15 18:24:32 -07:00 • committed by Kumar Gala
commit aed767a98c
1 changed files with 15 additions and 4 deletions
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19
lib/libc/newlib/libc-hooks.c
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@ -16,6 +16,7 @@
#include <syscall_handler.h> #include <syscall_handler.h>
#include <app_memory/app_memdomain.h> #include <app_memory/app_memdomain.h>
#include <init.h> #include <init.h>
#include <sys/sem.h>
#define LIBC_BSS K_APP_BMEM(z_libc_partition) #define LIBC_BSS K_APP_BMEM(z_libc_partition)
#define LIBC_DATA K_APP_DMEM(z_libc_partition) #define LIBC_DATA K_APP_DMEM(z_libc_partition)
@ -237,20 +238,30 @@ void _exit(int status)
} }
} }
static LIBC_DATA SYS_SEM_DEFINE(heap_sem, 1, 1);
void *_sbrk(int count) void *_sbrk(int count)
{ {
void *ret, *ptr;
sys_sem_take(&heap_sem, K_FOREVER);
#if CONFIG_NEWLIB_LIBC_ALIGNED_HEAP_SIZE #if CONFIG_NEWLIB_LIBC_ALIGNED_HEAP_SIZE
void *ptr = heap_base + heap_sz; ptr = heap_base + heap_sz;
#else #else
void *ptr = ((char *)HEAP_BASE) + heap_sz; ptr = ((char *)HEAP_BASE) + heap_sz;
#endif #endif
if ((heap_sz + count) < MAX_HEAP_SIZE) { if ((heap_sz + count) < MAX_HEAP_SIZE) {
heap_sz += count; heap_sz += count;
return ptr; ret = ptr;
} else { } else {
return (void *)-1; ret = (void *)-1;
} }
sys_sem_give(&heap_sem);
return ret;
} }
FUNC_ALIAS(_sbrk, sbrk, void *); FUNC_ALIAS(_sbrk, sbrk, void *);