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context.h
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#ifndef CEXP_CONTEXT_H
#define CEXP_CONTEXT_H
/* SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03
*
* Authorship
* ----------
* This software (CEXP - C-expression interpreter and runtime
* object loader/linker) was created by
*
* Till Straumann <[email protected]>, 2002-2008,
* Stanford Linear Accelerator Center, Stanford University.
*
* Acknowledgement of sponsorship
* ------------------------------
* This software was produced by
* the Stanford Linear Accelerator Center, Stanford University,
* under Contract DE-AC03-76SFO0515 with the Department of Energy.
*
* Government disclaimer of liability
* ----------------------------------
* Neither the United States nor the United States Department of Energy,
* nor any of their employees, makes any warranty, express or implied, or
* assumes any legal liability or responsibility for the accuracy,
* completeness, or usefulness of any data, apparatus, product, or process
* disclosed, or represents that its use would not infringe privately owned
* rights.
*
* Stanford disclaimer of liability
* --------------------------------
* Stanford University makes no representations or warranties, express or
* implied, nor assumes any liability for the use of this software.
*
* Stanford disclaimer of copyright
* --------------------------------
* Stanford University, owner of the copyright, hereby disclaims its
* copyright and all other rights in this software. Hence, anyone may
* freely use it for any purpose without restriction.
*
* Maintenance of notices
* ----------------------
* In the interest of clarity regarding the origin and status of this
* SLAC software, this and all the preceding Stanford University notices
* are to remain affixed to any copy or derivative of this software made
* or distributed by the recipient and are to be affixed to any copy of
* software made or distributed by the recipient that contains a copy or
* derivative of this software.
*
* SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03
*/
/* Cexp Context Interface. Declares data belonging to a running instance
* of Cexp which must be globally accessible. (E.g. for 'longjumping' out
* of nested routines etc.)
*
* Currently, this only works on RTEMS in a multithreaded way. RTEMS
* features 'task_variables', i.e. memory locations who appear to belong
* to a task's context. The contents are magically exchanged at context
* switch time.
*
* Note that there are actually 'context stacks' since cexp may recursively
* invoke itself. Every instance of cexp() owns a CexpContextRec these
* records are linked together 'per thread' using the 'next' field.
* In an environment which implements task variables, 'cexpCurrentContext'
* always points to the context of the innermost cexp instance of the
* current task's stack.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cexp.h"
#ifdef USE_EPICS_OSI
/* BFD redefines INLINE if we don't include epicsThread.h first; sigh... */
#include <epicsThread.h>
#endif
#ifdef HAVE_TECLA
#include <libtecla.h>
#endif
#ifdef HAVE_BFD_DISASSEMBLER
#define boolean bbbboooolean /* se comment in bfdstuff.c why we do that */
#include "ansidecl.h"
#include "dis-asm.h"
#undef boolean
#endif
#include <setjmp.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef struct CexpContextRec_ {
CexpContext next;
jmp_buf jbuf; /* for setjmp/longjmp */
char *prompt;
CexpParserCtx parser;
#ifdef HAVE_TECLA
GetLine *gl; /* line editor context; this could actually be one context per thread */
#endif
#ifdef HAVE_BFD_DISASSEMBLER
disassemble_info dinfo; /* context for the disassembler */
#endif
} CexpContextRec;
/* register/unregister the cexpCurrentContext with the OS */
void cexpContextRegister(void);
void cexpContextUnregister(void);
/* retrieve/set the current task's context */
void cexpContextGetCurrent(CexpContext *);
void cexpContextSetCurrent(CexpContext);
/* Note that the Register/Unregister and the Set/Get
* semantics are actually two different approaches to
* the problem.
* Register/Unregister is used in combination with
* RTEMS task variables (Get/Set map to simple
* variable assignments in this case).
* Get/Set are used by the EPICS or pthread APIs
* where a task specific variable must explicitely
* retrieved and stored (Register/Unregister do
* nothing in this case).
*/
#ifdef NO_THREAD_PROTECTION
typedef CexpContext CexpContextOSD;
#define cexpContextInitOnce() (cexpCurrentContext = 0, 0)
#define cexpContextRegister() do {} while (0)
#define cexpContextUnregister() do {} while(0)
#define cexpContextGetCurrent(pc) do { *(pc) = cexpCurrentContext; } while (0)
#define cexpContextSetCurrent(c) do { cexpCurrentContext=(c); } while (0)
#define cexpContextRunOnce(pdone, fn) do { if (!(*(pdone))) { \
(*(pdone))++; fn(0); \
} \
} while (0)
#elif defined(USE_EPICS_OSI)
typedef epicsThreadPrivateId CexpContextOSD;
#define cexpContextInitOnce() (! (cexpCurrentContext || \
(cexpCurrentContext = epicsThreadPrivateCreate()) )
#define cexpContextRegister() do { } while (0)
#define cexpContextUnregister() do { } while (0)
#define cexpContextGetCurrent(pc) do { *(pc) = (CexpContext)epicsThreadPrivateGet( \
cexpCurrentContext \
); \
} while (0))
#define cexpContextSetCurrent(c) epicsThreadPrivateSet(cexpCurrentContext,(c))
#define cexpContextRunOnce(pdone, fn) epicsThreadOnce(pdone,(void (*)(void*))fn,0)
#elif defined(HAVE_PTHREADS)
#include <pthread.h>
typedef pthread_key_t CexpContextOSD;
#define cexpContextInitOnce() pthread_key_create(&cexpCurrentContext,0)
#define cexpContextRunOnce(pdone, fn) do { if (!(*(pdone))) { \
(*(pdone))++; fn(0); \
} \
} while (0)
#define cexpContextRegister() do { } while (0)
#define cexpContextUnregister() do { } while (0)
#define cexpContextGetCurrent(pc) do { *pc = pthread_getspecific(cexpCurrentContext); } while (0)
#define cexpContextSetCurrent(c) pthread_setspecific(cexpCurrentContext, c)
#elif defined(__rtems__)
#ifdef HAVE_RTEMS_H /* see cexplock.h comment */
#include <rtems.h>
#if __RTEMS_MAJOR__ < 4 || ( __RTEMS_MAJOR__ == 4 && __RTEMS_MINOR__ < 7 )
#error "Using a notepad is currently unsupported - it must be initialized to 0 at task creation and your version of RTEMS is too old to do that"
#endif
#else
#define RTEMS_SELF 0
#ifdef CEXP_RTEMS_NOTEPAD
/* RTEMS >= 4.7 does zero the notepads but we can't check the version w/o headers */
#error Using a notepad is currently unsupported - it must be initialized to 0 at task creation and I dont know how to do that
#endif
#ifdef CEXP_RTEMS_NOTEPAD
long rtems_task_get_note();
long rtems_task_set_note();
#else
/* use task vars - discouraged */
long rtems_task_variable_add();
long rtems_task_variable_delete();
#endif
#endif
typedef CexpContext CexpContextOSD;
/* We assume the first instance of 'cexp' will be executed by
* an initialization task or a an initialization task will
* explicitely call cexpInit(), hence we don't bother
* about race conditions in cexpInit().
*/
#define cexpContextInitOnce() (cexpCurrentContext = 0, 0)
#define cexpContextRunOnce(pdone, fn) do { if (!(*(pdone))) { \
(*(pdone))++; fn(0); \
} \
} while (0)
#ifdef CEXP_RTEMS_NOTEPAD
#define cexpContextRegister() do {} while (0)
#define cexpContextUnregister() do {} while (0)
#define cexpContextGetCurrent(pc) do { \
rtems_task_get_note( \
RTEMS_SELF, \
CEXP_RTEMS_NOTEPAD, \
(pc) \
); \
} while (0)
#define cexpContextSetCurrent(c) do { \
rtems_task_set_note( \
RTEMS_SELF, \
CEXP_RTEMS_NOTEPAD, \
(c) \
); \
} while (0)
#else /* task var variant (discouraged - increases context switch latency) */
#define cexpContextRegister() do { \
rtems_task_variable_add(\
RTEMS_SELF,\
(void*)&cexpCurrentContext,\
0 /* context is part of the stack, hence\
* released automatically\
*/); \
} while (0)
#define cexpContextUnregister() do { \
rtems_task_variable_delete(\
RTEMS_SELF,\
(void*)&cexpCurrentContext); \
} while (0)
#define cexpContextGetCurrent(pc) do { *(pc) = cexpCurrentContext; } while (0)
#define cexpContextSetCurrent(c) do { cexpCurrentContext=(c); } while (0)
#endif
#else
#error "You need to implement cexpContextRegister & friends for this OS"
#endif
/* OS dependent representation of the thread context */
extern CexpContextOSD cexpCurrentContext;
#ifdef __cplusplus
}
#endif
#endif