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Fix vfork(). Now that arguments are kept on the stack, the way that arguments are passed from parent to child in vfork() must change. This bug has always been present, but was not visible with the old strdup() way of passing arguments

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This commit is contained in:
Gregory Nutt 2014-09-29 10:45:44 -06:00
parent d0b0e089a7
commit 2b0c657b1f
1 changed files with 10 additions and 10 deletions
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20
arch/arm/src/common/up_vfork.c
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@ -102,7 +102,7 @@
* - Allocation of the child task's TCB. * - Allocation of the child task's TCB.
* - Initialization of file descriptors and streams * - Initialization of file descriptors and streams
* - Configuration of environment variables * - Configuration of environment variables
* - Setup the intput parameters for the task. * - Setup the input parameters for the task.
* - Initialization of the TCB (including call to up_initial_state() * - Initialization of the TCB (including call to up_initial_state()
* 4) up_vfork() provides any additional operating context. up_vfork must: * 4) up_vfork() provides any additional operating context. up_vfork must:
* - Allocate and initialize the stack * - Allocate and initialize the stack
@ -113,7 +113,7 @@
* *
* task_vforkabort() may be called if an error occurs between steps 3 and 6. * task_vforkabort() may be called if an error occurs between steps 3 and 6.
* *
* Input Paremeters: * Input Parameters:
* context - Caller context information saved by vfork() * context - Caller context information saved by vfork()
* *
* Return: * Return:
@ -147,15 +147,15 @@ pid_t up_vfork(const struct vfork_s *context)
child = task_vforksetup((start_t)(context->lr & ~1)); child = task_vforksetup((start_t)(context->lr & ~1));
if (!child) if (!child)
{ {
sdbg("task_vforksetup failed\n"); sdbg("ERROR: task_vforksetup failed\n");
return (pid_t)ERROR; return (pid_t)ERROR;
} }
svdbg("Parent=%p Child=%p\n", parent, child); svdbg("TCBs: Parent=%p Child=%p\n", parent, child);
/* Get the size of the parent task's stack. Due to alignment operations, /* Get the size of the parent task's stack. Due to alignment operations,
* the adjusted stack size may be smaller than the stack size originally * the adjusted stack size may be smaller than the stack size originally
* requrested. * requested.
*/ */
stacksize = parent->adj_stack_size + CONFIG_STACK_ALIGNMENT - 1; stacksize = parent->adj_stack_size + CONFIG_STACK_ALIGNMENT - 1;
@ -166,7 +166,7 @@ pid_t up_vfork(const struct vfork_s *context)
parent->flags & TCB_FLAG_TTYPE_MASK); parent->flags & TCB_FLAG_TTYPE_MASK);
if (ret != OK) if (ret != OK)
{ {
sdbg("up_create_stack failed: %d\n", ret); sdbg("ERROR: up_create_stack failed: %d\n", ret);
task_vforkabort(child, -ret); task_vforkabort(child, -ret);
return (pid_t)ERROR; return (pid_t)ERROR;
} }
@ -180,9 +180,9 @@ pid_t up_vfork(const struct vfork_s *context)
DEBUGASSERT((uint32_t)parent->adj_stack_ptr > context->sp); DEBUGASSERT((uint32_t)parent->adj_stack_ptr > context->sp);
stackutil = (uint32_t)parent->adj_stack_ptr - context->sp; stackutil = (uint32_t)parent->adj_stack_ptr - context->sp;
svdbg("stacksize:%d stackutil:%d\n", stacksize, stackutil); svdbg("Parent: stacksize:%d stackutil:%d\n", stacksize, stackutil);
/* Make some feeble effort to perserve the stack contents. This is /* Make some feeble effort to preserve the stack contents. This is
* feeble because the stack surely contains invalid pointers and other * feeble because the stack surely contains invalid pointers and other
* content that will not work in the child context. However, if the * content that will not work in the child context. However, if the
* user follows all of the caveats of vfork() usage, even this feeble * user follows all of the caveats of vfork() usage, even this feeble
@ -205,9 +205,9 @@ pid_t up_vfork(const struct vfork_s *context)
newfp = context->fp; newfp = context->fp;
} }
svdbg("Old stack base:%08x SP:%08x FP:%08x\n", svdbg("Parent: stack base:%08x SP:%08x FP:%08x\n",
parent->adj_stack_ptr, context->sp, context->fp); parent->adj_stack_ptr, context->sp, context->fp);
svdbg("New stack base:%08x SP:%08x FP:%08x\n", svdbg("Child: stack base:%08x SP:%08x FP:%08x\n",
child->cmn.adj_stack_ptr, newsp, newfp); child->cmn.adj_stack_ptr, newsp, newfp);
/* Update the stack pointer, frame pointer, and volatile registers. When /* Update the stack pointer, frame pointer, and volatile registers. When