PCSC那事儿(十七--SCardGetStatusChange)

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SCardGetStatusChange

SCardGetStatusChange定义在winscard_clnt.c

实现如下：

1872 LONG SCardGetStatusChange(SCARDCONTEXT hContext, DWORD dwTimeout,

1873 LPSCARD_READERSTATE_A rgReaderStates, DWORD cReaders)

1874 {

1875 PSCARD_READERSTATE_A currReader;

1876 PREADER_STATE rContext;

1877 long dwTime = dwTimeout;

1878 DWORD dwState;

1879 DWORD dwBreakFlag = 0;

1880 int j;

1881 LONG dwContextIndex;

1882 int currentReaderCount = 0;

1883 LONG rv = SCARD_S_SUCCESS;

1884

1885 PROFILE_START

1886

1887 if ((rgReaderStates == NULL && cReaders > 0)

1888 || (cReaders > PCSCLITE_MAX_READERS_CONTEXTS))

1889 return SCARD_E_INVALID_PARAMETER;

1890

1891 /* Check the integrity of the reader states structures */

1892 for (j = 0; j < cReaders; j++)

1893 {

1894 if (rgReaderStates[j].szReader == NULL)

1895 return SCARD_E_INVALID_VALUE;

1896 }

1887~1889行，1892~1896行，两组条件检查，easy，不是吗？

1898 /* return if all readers are SCARD_STATE_IGNORE */

1899 if (cReaders > 0)

1900 {

1901 int nbNonIgnoredReaders = cReaders;

1902

1903 for (j=0; j<cReaders; j++)

1904 if (rgReaderStates[j].dwCurrentState & SCARD_STATE_IGNORE)

1905 nbNonIgnoredReaders--;

1906

1907 if (0 == nbNonIgnoredReaders)

1908 return SCARD_S_SUCCESS;

1909 }

1898~1909行说明如果当前所有读卡器状态是 SCARD_STATE_IGNORE，

则直接返回，因为这个标志，代表APPLICATION不想知道读卡器的状态。

不想知道，就不要再去获取读卡器的状态了。APPLICATION不想要，

ResourceManager也不好意硬给。

SCARD_STATE_xxx等n多状态，见上面的卷5分析。

1911 rv = SCardCheckDaemonAvailability();

1912 if (rv != SCARD_S_SUCCESS)

1913 return rv;

1914

1915 /*

1916 * Make sure this context has been opened

1917 */

1918 dwContextIndex = SCardGetContextIndice(hContext);

1919 if (dwContextIndex == -1)

1920 return SCARD_E_INVALID_HANDLE;

1921

1922 (void)SYS_MutexLock(psContextMap[dwContextIndex].mMutex);

1923

1924 /* check the context is still opened */

1925 dwContextIndex = SCardGetContextIndice(hContext);

1926 if (dwContextIndex == -1)

1927 /* the context is now invalid

1928 * -> another thread may have called SCardReleaseContext

1929 * -> so the mMutex has been unlocked */

1930 return SCARD_E_INVALID_HANDLE;

1911~1930行，略过，说了n次。

1938 if (cReaders == 0)

1939 {

1940 while (1)

1941 {

1942 int i;

1943

1944 rv = SCardCheckDaemonAvailability();

1945 if (rv != SCARD_S_SUCCESS)

1946 goto end;

1947

1948 for (i = 0; i < PCSCLITE_MAX_READERS_CONTEXTS; i++)

1949 {

1950 if ((readerStates[i])->readerID != 0)

1951 {

1952 /* Reader was found */

1953 rv = SCARD_S_SUCCESS;

1954 goto end;

1955 }

1956 }

1938行，可是特殊情况， cReaders==0，表示想等待第一台可用的读卡器。

只要有一台可用，则 SCardGetStatusChange成功返回。

1944 行，略过。

1948~1956行，再次查询readerStates状态，如果查到有可用的读卡器，

则成功返回。别忘记，readerStates可是共享内存。

1958 if (dwTimeout == 0)

1959 {

1960 /* return immediately - no reader available */

1961 rv = SCARD_E_READER_UNAVAILABLE;

1962 goto end;

1963 }

1958行表示即使目前没有可用的读卡器，函数也立刻返回，

不用进入超时等待可用的读卡器。

1965 dwTime = WaitForPcscdEvent(hContext, dwTime);

1966 if (dwTimeout != INFINITE)

1967 {

1968 if (dwTime <= 0)

1969 {

1970 rv = SCARD_E_TIMEOUT;

1971 goto end;

1972 }

1973 }

1974 }

1975 }

1965~1975行，在dwTime设定的时间内等待读卡器事件的出现。事件是通过文件fifo来实现的。

1877 long dwTime = dwTimeout;

如果dwTimeout没有设置为INFINITE，则如果在设定时间内，

没有出现事件，则超时返回。

否则 WaitForPcscdEvent将永远等待。

Waiting for eventsfrom Monday to Sunday.

1965行，WaitForPcscdEvent在winscard_clnt.c中定义

实现如下：

1724 static long WaitForPcscdEvent(SCARDCONTEXT hContext, long dwTime)

1725 {

1726 char filename[FILENAME_MAX];

1727 char buf[1];

1728 int fd, r;

1729 struct timeval tv, *ptv = NULL;

1730 struct timeval before, after;

1731 fd_set read_fd;

1732

1733 if (INFINITE != dwTime)

1734 {

1735 if (dwTime < 0)

1736 return 0;

1737 gettimeofday(&before, NULL);

1738 tv.tv_sec = dwTime/1000;

1739 tv.tv_usec = dwTime*1000 - tv.tv_sec*1000000;

1740 ptv = &tv;

1741 }

1742

1743 (void)snprintf(filename, sizeof(filename), "%s/event.%d.%ld",

1744 PCSCLITE_EVENTS_DIR, SYS_GetPID(), hContext);

1745 r = mkfifo(filename, 0644);

1746 if (-1 == r)

1747 {

1748 Log2(PCSC_LOG_CRITICAL, "Can't create event fifo: %s", strerror(errno));

1749 goto exit;

1750 }

1751

1752 fd = SYS_OpenFile(filename, O_RDONLY | O_NONBLOCK, 0);

1753

1754 /* the file may have been removed between the mkfifo() and open() */

1755 if (-1 != fd)

1756 {

1757 FD_ZERO(&read_fd);

1758 FD_SET(fd, &read_fd);

1759

1760 (void)select(fd+1, &read_fd, NULL, NULL, ptv);

1761

1762 (void)SYS_ReadFile(fd, buf, 1);

1763 (void)SYS_CloseFile(fd);

1764 }

1765

1766 (void)SYS_RemoveFile(filename);

1767

1768 if (INFINITE != dwTime)

1769 {

1770 long int diff;

1771

1772 gettimeofday(&after, NULL);

1773 diff = time_sub(&after, &before);

1774 dwTime -= diff/1000;

1775 }

1776

1777 exit:

1778 return dwTime;

1779 }

1738行，　 tv.tv_sec = dwTime/1000;

说明dwTime的粒度是ms.

1745行　mkfifo明确地说明，event就是fifo，文件fifo不是匿名fifo通讯。

1752行　SYS_OpenFile打开fifo文件，非阻塞方式。fifo文件存在于

PCSCLITE_EVENTS_DIR也就是/var/run/pcscd/pcscd.events

文件名以APPLICATION的pid和hContext组合。

1760行　select进行超时读取。

1768~1775行　返回剩余的等待时间。当然如果是dwTime==INFINITE，

则select将永久等待，知道fifo可读。

select永久等待。因为它知道，会有读卡器来。所以它一直等。

而在现实中呢？比如select某人，永久？那只是在歌词所咏颂的情景中才会出现的故事。

现实中的绝大部分故事解决注定是悲剧。

现实总是和理想相差太远。昨天盼今天，今天盼明天，年头盼年尾，

今年盼明年。所谓希望总是有的。哈哈...

问：想知道fifo是谁写入的。

答案是，继续看吧，到了第三章的服务端解说，就有知道的。

回头，继续。

回到 SCardGetStatusChange

1938~1975完成。但是1935~1936有行，原版注释

1935 * This is DEPRECATED. Use the special reader name //?PnP?/Notification

1936 * instead

也就是1938~1975已经放弃了，估计是为了兼容以前的版本，现在要探测

可用的读卡器，是使用特殊的读卡器名字来调用SCardGetStatusChange。

这个名字就是//?PnP?/Notification

。多in的名字呀，PnP，

这和ms有很大的关系呀，和大佬攀上关系。那当然好。现实中也有很多

这样高攀的例子。别抱怨，你有背景吗？你有天线吗？没有，那么请take a hike.

继续。

1882 int currentReaderCount = 0;

currentReaderCount当前系统中的读卡器数量初始化为０.

1976

1977 /*

1978 * End of search for readers

1979 */

1980

1981 /* Clear the event state for all readers */

1982 for (j = 0; j < cReaders; j++)

1983 rgReaderStates[j].dwEventState = 0;

1984

1985 /* Now is where we start our event checking loop */

1986 Log1(PCSC_LOG_DEBUG, "Event Loop Start");

1987

1988 psContextMap[dwContextIndex].contextBlockStatus = BLOCK_STATUS_BLOCKING;

1989

1976~1989行，正如注释说。

1990 /* Get the initial reader count on the system */

1991 for (j=0; j < PCSCLITE_MAX_READERS_CONTEXTS; j++)

1992 if ((readerStates[j])->readerID != 0)

1993 currentReaderCount++;

1990~1993获取系统中目前可用的读卡器数量.目的是准备和参数中传入

的给定名字的读卡器进行比对，确定状态变化。

1995 j = 0;

1996 do

1997 {

1998 rv = SCardCheckDaemonAvailability();

1999 if (rv != SCARD_S_SUCCESS)

2000 {

2001 if (psContextMap[dwContextIndex].mMutex)

2002 (void)SYS_MutexUnLock(psContextMap[dwContextIndex].mMutex);

2003

2004 PROFILE_END(rv)

2005

2006 return rv;

2007 }

2008

2009 currReader = &rgReaderStates[j];

接下来就逐个比对了。

1998行，再次判断服务端是否存在。

2009行，从参数获取第j个读卡器状态。要开始比对了。

2012 if (!(currReader->dwCurrentState & SCARD_STATE_IGNORE))

2013 {

2014 LPSTR lpcReaderName;

2015 int i;

2016

2017 /************ Looks for correct readernames *********************/

2018

2019 lpcReaderName = (char *) currReader->szReader;

2020

2021 for (i = 0; i < PCSCLITE_MAX_READERS_CONTEXTS; i++)

2022 {

2023 if (strcmp(lpcReaderName, (readerStates[i])->readerName) == 0)

2024 break;

2025 }

2012行，SCARD_STATE_IGNORE，前面提过了。

2023行，开始比对名字，把参数传入的读卡器数组名字逐个和所有的readerStates的readerName进行比较。

2028 if (i == PCSCLITE_MAX_READERS_CONTEXTS)

2029 {

2028~2029说明参数传入的读卡器 currReader当前不存在于系统中。

存在两种可能，就是currReader的名字是否是"////?PnP?//Notification"，正如上面所说的，

如果和ms有莫大关系，自然要特殊情况特殊处理呀。

特殊关照如下

2031 if (strcasecmp(lpcReaderName, "////?PnP?//Notification") == 0)

2032 {

2033 int k, newReaderCount = 0;

2034

2035 for (k=0; k < PCSCLITE_MAX_READERS_CONTEXTS; k++)

2036 if ((readerStates[k])->readerID != 0)

2037 newReaderCount++;

2038

2039 if (newReaderCount != currentReaderCount)

2040 {

2041 Log1(PCSC_LOG_INFO, "Reader list changed");

2042 currentReaderCount = newReaderCount;

2043

2044 currReader->dwEventState |= SCARD_STATE_CHANGED;

2045 dwBreakFlag = 1;

2046 }

2047 }

2031~2047 看来有些着急，毕竟是ms委托的。

原先在1993的时候，已经获得了currentReaderCount。

现在立刻再次获取当前的ReaderCount，也就是 newReaderCount。

如果相比currentReaderCount，有变化，不管少了还是多了。赶紧上报。并标志

currReader->dwEventState.

2048 else

2049 {

2050 currReader->dwEventState = SCARD_STATE_UNKNOWN | SCARD_STATE_UNAVA ILABLE;

2051 if (!(currReader->dwCurrentState & SCARD_STATE_UNKNOWN))

2052 {

2053 currReader->dwEventState |= SCARD_STATE_CHANGED;

2054 /*

2055 * Spec says use SCARD_STATE_IGNORE but a removed USB

2056 * reader with eventState fed into currentState will

2057 * be ignored forever

2058 */

2059 dwBreakFlag = 1;

2060 }

2061 }

2048行说明对于currReader没有比对成功。修改 currReader->dwEventState.

SCARD_STATE_xxx，前面提过了，卷5也提过了。

接下来是什么呢？当然是比对成功情况下的具体处理。

更新currReaderd的dwEventState.

2063 else

2064 {

2065 /* The reader has come back after being away */

2066 if (currReader->dwCurrentState & SCARD_STATE_UNKNOWN)

2067 {

2068 currReader->dwEventState |= SCARD_STATE_CHANGED;

2069 currReader->dwEventState &= ~SCARD_STATE_UNKNOWN;

2070 Log0(PCSC_LOG_DEBUG);

2071 dwBreakFlag = 1;

2072 }

2073

2074 /*****************************************************************/

2075

2076 /* Set the reader status structure */

2077 rContext = readerStates[i];

2078

2076 /* Set the reader status structure */

2077 rContext = readerStates[i];

2078

2079 /* Now we check all the Reader States */

2080 dwState = rContext->readerState;

2081

2082 /* only if current state has an non null event counter */

2083 if (currReader->dwCurrentState & 0xFFFF0000)

2084 {

2085 int currentCounter, stateCounter;

2086

2087 stateCounter = (dwState >> 16) & 0xFFFF;

2088 currentCounter = (currReader->dwCurrentState >> 16) & 0xFFFF;

2089

2090 /* has the event counter changed since the last call? */

2091 if (stateCounter != currentCounter)

2092 {

2093 currReader->dwEventState |= SCARD_STATE_CHANGED;

2094 Log0(PCSC_LOG_DEBUG);

2095 dwBreakFlag = 1;

2096 }

2097

2098 /* add an event counter in the upper word of dwEventState */

2099 currReader->dwEventState =

2100 ((currReader->dwEventState & 0xffff )

2101 | (stateCounter << 16));

2102 }

原来currReader->dwCurrentState的类型是unsignedlong(4字节,由体系结构决定),高16位(31~16bit)用来装currReader的当前事件计数。

2083~2102行，把currReader和前面找到的和currReader读卡器名字相同的readerStates

进行计数比较，确定系统中原本已经存在的读卡器是否发生了新的事件。原本就存在于系统中的读卡器，是否发生状态变化，还得依靠计数。

把当前计数更新到currReader->dwEventState.

接着从readerStates也就是共享内存中进一步获取当前读卡器当前状态，与currReader->dwCurrentState也就是APPLICATION传入的状态，进行比对，进一步确定发生的具体事件。

2104 /*********** Check if the reader is in the correct state ********/

2105 if (dwState & SCARD_UNKNOWN)

2106 {

2107 /* reader is in bad state */

2108 currReader->dwEventState = SCARD_STATE_UNAVAILABLE;

2109 if (!(currReader->dwCurrentState & SCARD_STATE_UNAVAILABLE))

2110 {

2111 /* App thinks reader is in good state and it is not */

2112 currReader->dwEventState |= SCARD_STATE_CHANGED;

2113 Log0(PCSC_LOG_DEBUG);

2114 dwBreakFlag = 1;

2115 }

2116 }

2117 else

2118 {

2119 /* App thinks reader in bad state but it is not */

2120 if (currReader-> dwCurrentState & SCARD_STATE_UNAVAILABLE)

2121 {

2122 currReader->dwEventState &= ~SCARD_STATE_UNAVAILABLE;

2123 currReader->dwEventState |= SCARD_STATE_CHANGED;

2124 Log0(PCSC_LOG_DEBUG);

2125 dwBreakFlag = 1;

2126 }

2127 }

2128

2129 /********** Check for card presence in the reader **************/

2130

2131 if (dwState & SCARD_PRESENT)

2132 {

2133 /* card present but not yet powered up */

2134 if (0 == rContext->cardAtrLength)

2135 /* Allow the status thread to convey information */

2136 (void)SYS_USleep(PCSCLITE_STATUS_POLL_RATE + 10);

2137

2138 currReader->cbAtr = rContext->cardAtrLength;

2139 memcpy(currReader->rgbAtr, rContext->cardAtr,

2140 currReader->cbAtr);

2141 }

2142 else

2143 currReader->cbAtr = 0;

2144

2145 /* Card is now absent */

2146 if (dwState & SCARD_ABSENT)

2147 {

2148 currReader->dwEventState |= SCARD_STATE_EMPTY;

2149 currReader->dwEventState &= ~SCARD_STATE_PRESENT;

2150 currReader->dwEventState &= ~SCARD_STATE_UNAWARE;

2151 currReader->dwEventState &= ~SCARD_STATE_IGNORE;

2152 currReader->dwEventState &= ~SCARD_STATE_UNKNOWN;

2153 currReader->dwEventState &= ~SCARD_STATE_UNAVAILABLE;

2154 currReader->dwEventState &= ~SCARD_STATE_ATRMATCH;

2155 currReader->dwEventState &= ~SCARD_STATE_MUTE;

2156 currReader->dwEventState &= ~SCARD_STATE_INUSE;

2157

2158 /* After present the rest are assumed */

2159 if (currReader->dwCurrentState & SCARD_STATE_PRESENT)

2160 {

2161 currReader->dwEventState |= SCARD_STATE_CHANGED;

2162 Log0(PCSC_LOG_DEBUG);

2163 dwBreakFlag = 1;

2164 }

2165 }

2166 /* Card is now present */

2167 else if (dwState & SCARD_PRESENT)

2168 {

2169 currReader->dwEventState |= SCARD_STATE_PRESENT;

2170 currReader->dwEventState &= ~SCARD_STATE_EMPTY;

2171 currReader->dwEventState &= ~SCARD_STATE_UNAWARE;

2172 currReader->dwEventState &= ~SCARD_STATE_IGNORE;

2173 currReader->dwEventState &= ~SCARD_STATE_UNKNOWN;

2174 currReader->dwEventState &= ~SCARD_STATE_UNAVAILABLE;

2175 currReader->dwEventState &= ~SCARD_STATE_MUTE;

2176

2177 if (currReader->dwCurrentState & SCARD_STATE_EMPTY)

2178 {

2179 currReader->dwEventState |= SCARD_STATE_CHANGED;

2180 Log0(PCSC_LOG_DEBUG);

2181 dwBreakFlag = 1;

2182 }

2183

2184 if (dwState & SCARD_SWALLOWED)

2185 {

2186 currReader->dwEventState |= SCARD_STATE_MUTE;

2187 if (!(currReader->dwCurrentState & SCARD_STATE_MUTE))

2188 {

2189 currReader->dwEventState |= SCARD_STATE_CHANGED;

2190 Log0(PCSC_LOG_DEBUG);

2191 dwBreakFlag = 1;

2192 }

2193 }

2194 else

2195 {

2196 /* App thinks card is mute but it is not */

2197 if (currReader->dwCurrentState & SCARD_STATE_MUTE)

2198 {

2199 currReader->dwEventState |= SCARD_STATE_CHANGED;

2200 Log0(PCSC_LOG_DEBUG);

2201 dwBreakFlag = 1;

2202 }

2203 }

2204 }

2104~2204都很好理解的，主要目的就是更新 currReader->dwEventState.

2205

2206 /* Now figure out sharing modes */

2207 if (rContext->readerSharing == -1)

2208 {

2209 currReader->dwEventState |= SCARD_STATE_EXCLUSIVE;

2210 currReader->dwEventState &= ~SCARD_STATE_INUSE;

2211 if (currReader->dwCurrentState & SCARD_STATE_INUSE)

2212 {

2213 currReader->dwEventState |= SCARD_STATE_CHANGED;

2214 Log0(PCSC_LOG_DEBUG);

2215 dwBreakFlag = 1;

2216 }

2217 }

2218 else if (rContext->readerSharing >= 1)

2219 {

2220 /* A card must be inserted for it to be INUSE */

2221 if (dwState & SCARD_PRESENT)

2222 {

2223 currReader->dwEventState |= SCARD_STATE_INUSE;

2224 currReader->dwEventState &= ~SCARD_STATE_EXCLUSIVE;

2225 if (currReader-> dwCurrentState & SCARD_STATE_EXCLUSIVE)

2226 {

2227 currReader->dwEventState |= SCARD_STATE_CHANGED;

2228 Log0(PCSC_LOG_DEBUG);

2229 dwBreakFlag = 1;

2230 }

2231 }

2232 }

2233 else if (rContext->readerSharing == 0)

2234 {

2235 currReader->dwEventState &= ~SCARD_STATE_INUSE;

2236 currReader->dwEventState &= ~SCARD_STATE_EXCLUSIVE;

2237

2238 if (currReader->dwCurrentState & SCARD_STATE_INUSE)

2239 {

2240 currReader->dwEventState |= SCARD_STATE_CHANGED;

2241 Log0(PCSC_LOG_DEBUG);

2242 dwBreakFlag = 1;

2243 }

2244 else if (currReader-> dwCurrentState

2245 & SCARD_STATE_EXCLUSIVE)

2246 {

2247 currReader->dwEventState |= SCARD_STATE_CHANGED;

2248 Log0(PCSC_LOG_DEBUG);

2249 dwBreakFlag = 1;

2250 }

2251 }

2205~2251行，对共享模式进行特殊处理。

rContext->readerSharing==-1表示目前读卡器处于排它模式，但是没有任何一个APPLICATION在使用读卡器。

rContext->readerSharing>= 1表示目前读卡器处于共享模式。且有多个应用同时在使用

读卡器。而rContext->readerSharing的值就是当前在该读卡器上所打开的上下文数量。

rContext->readerSharing== 0

rContext->readerSharing== 0表示当前的 readerStates已经处于初始状态。发生在reader

被移除。

2252

2253 if (currReader->dwCurrentState == SCARD_STATE_UNAWARE)

2254 {

2255 /*

2256 * Break out of the while .. loop and return status

2257 * once all the status's for all readers is met

2258 */

2259 currReader->dwEventState |= SCARD_STATE_CHANGED;

2260 Log0(PCSC_LOG_DEBUG);

2261 dwBreakFlag = 1;

2262 }

2263 } /* End of SCARD_STATE_UNKNOWN */

2264 } /* End of SCARD_STATE_IGNORE */

2253行　表示应用不知道目前读卡器的状态。

2259行　表示告知应用读卡器状态发生变化了。

2265

2266 /* Counter and resetter */

2267 j++;

2268 if (j == cReaders)

2269 {

2270 /* go back to the first reader */

2271 j = 0;

2272

2273 /* Declare all the break conditions */

2274

2275 /* Break if UNAWARE is set and all readers have been checked */

2276 if (dwBreakFlag == 1)

2277 break;

2278

2279 if (BLOCK_STATUS_RESUME

2280 == psContextMap[dwContextIndex].contextBlockStatus)

2281 break;

2282

2283 /* Only sleep once for each cycle of reader checks. */

2284 dwTime = WaitForPcscdEvent(hContext, dwTime);

2285

2286 if (dwTimeout != INFINITE)

2287 {

2288 /* If time is greater than timeout and all readers have been

2289 * checked

2290 */

2291 if (dwTime <= 0)

2292 {

2293 rv = SCARD_E_TIMEOUT;

2294 goto end;

2295 }

2296 }

2297 }

2298 }

2299 while (1);

2265~2299行，很好理解。

2284行，WaitForPcscdEvent，在每一次while(1)大循环中，等待事件。发生变化，更新

currReader的各状态。这就是while(1)内部循环体的任务。

2300

2301 if (psContextMap[dwContextIndex].contextBlockStatus == BLOCK_STATUS_RESUME)

2302 rv = SCARD_E_CANCELLED;

2303

2304 end:

2305 Log1(PCSC_LOG_DEBUG, "Event Loop End");

2306

2307 (void)SYS_MutexUnLock(psContextMap[dwContextIndex].mMutex);

2308

2309 PROFILE_END(rv)

2310

2311 return rv;

2312 }

在SCardGetStatusChange解说结束前，说说

contextBlockStatus，这个存在于

175 static struct _psContextMap

176 {

177 DWORD dwClientID; /**< Client Connection ID */

178 SCARDCONTEXT hContext; /**< Application Context ID */

179 DWORD contextBlockStatus;

180 PCSCLITE_MUTEX_T mMutex; /**< Mutex for this context */

181 CHANNEL_MAP psChannelMap[PCSCLITE_MAX_APPLICATION_CONTEXT_CHANNELS];

182 } psContextMap[PCSCLITE_MAX_APPLICATION_CONTEXTS];

没有注释说明 contextBlockStatus做什么的。

搜索整个工程，只有winscard_clnt.c用到，且只有９个地方用到。

这是一个状态值，且只有两个状态，定义于pcscd.h

#define BLOCK_STATUS_RESUME 0x00FF /**< Normal resume */

#define BLOCK_STATUS_BLOCKING 0x00FA /**< Function is blocking */

猜到了吧。

如果还没有，那么请看