Last change
on this file since 577 was
444,
checked in by satin@…, 6 years ago
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add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc
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File size:
1.4 KB
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Line | |
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1 | /* |
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2 | FUNCTION |
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3 | <<__env_lock>>, <<__env_unlock>>---lock environ variable |
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4 | |
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5 | INDEX |
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6 | __env_lock |
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7 | INDEX |
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8 | __env_unlock |
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9 | |
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10 | SYNOPSIS |
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11 | #include <envlock.h> |
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12 | void __env_lock (struct _reent *<[reent]>); |
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13 | void __env_unlock (struct _reent *<[reent]>); |
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14 | |
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15 | DESCRIPTION |
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16 | The <<setenv>> family of routines call these functions when they need to |
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17 | modify the environ variable. The version of these routines supplied in the |
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18 | library use the lock API defined in sys/lock.h. If multiple threads of |
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19 | execution can call <<setenv>>, or if <<setenv>> can be called reentrantly, |
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20 | then you need to define your own versions of these functions in order to |
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21 | safely lock the memory pool during a call. If you do not, the memory pool |
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22 | may become corrupted. |
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23 | |
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24 | A call to <<setenv>> may call <<__env_lock>> recursively; that is, |
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25 | the sequence of calls may go <<__env_lock>>, <<__env_lock>>, |
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26 | <<__env_unlock>>, <<__env_unlock>>. Any implementation of these |
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27 | routines must be careful to avoid causing a thread to wait for a lock |
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28 | that it already holds. |
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29 | */ |
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30 | |
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31 | #include "envlock.h" |
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32 | #include <sys/lock.h> |
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33 | |
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34 | #ifndef __SINGLE_THREAD__ |
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35 | __LOCK_INIT_RECURSIVE(static, __env_recursive_mutex); |
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36 | #endif |
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37 | |
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38 | void |
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39 | __env_lock (ptr) |
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40 | struct _reent *ptr; |
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41 | { |
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42 | #ifndef __SINGLE_THREAD__ |
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43 | __lock_acquire_recursive (__env_recursive_mutex); |
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44 | #endif |
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45 | } |
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46 | |
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47 | void |
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48 | __env_unlock (ptr) |
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49 | struct _reent *ptr; |
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50 | { |
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51 | #ifndef __SINGLE_THREAD__ |
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52 | __lock_release_recursive (__env_recursive_mutex); |
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53 | #endif |
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54 | } |
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