Android重定向文件代码编写,Android，CMDTool，stdout重定向，“致命信号11（SIGSEGV）”...

用例

Android C命令行工具lunching“/ system / bin / getprop”并将其stdout重定向到套接字

问题

启动'getprop'失败，出现“F / libc(20694)：致命信号11(SIGSEGV)，代码1，故障地址0x0，tid 20694(getprop)”，代码和logcat片段如下 .

为什么我会收到SIGSEGV？为什么分叉过程失败？

实施

HRESULT ServiceCore::CreateProcessAndRedirectStdout(IN char* pCmd, IN char** args, OUT SOCKET& stdoutstream) {

HRESULT hr = S_OK;

int fds[2] = { 0 };

pid_t pid = 0;

stdoutstream = 0;

if (SOCKET_ERROR == socketpair(PF_UNIX, SOCK_STREAM, 0, fds))

goto ErrExit;

stdoutstream = fds[1];

if((pid = fork()) < 0)

goto ErrExit;

if (pid == 0) {

// The newly created process

__android_log_print(ANDROID_LOG_INFO, "ServiceCore", "CreateProcessAndRedirectStdout>> '%s' started", pCmd);

int newfd = dup2(fds[0], STDOUT_FILENO);

__android_log_print(ANDROID_LOG_INFO, "ServiceCore", "CreateProcessAndRedirectStdout>> '%s' newfd:%d, oldfd:%d", pCmd, newfd, fds[0]);

_ASSERT(newfd == STDOUT_FILENO);

close(fds[0]);

close(fds[1]);

execvp(pCmd, args);

__android_log_print(ANDROID_LOG_INFO, "ServiceCore", "CreateProcessAndRedirectStdout>> '%s' FAILED", pCmd);

exit(1);

}

__android_log_print(ANDROID_LOG_INFO, "ServiceCore", "CreateProcessAndRedirectStdout>> '%s(%d)' Created", pCmd, pid);

return S_OK;

ErrExit:

if (0 != pid)

kill(pid, SIGTERM);

close(fds[0]);

close(fds[1]);

stdoutstream = 0;

return hr;

}

...

char* args[] = { 0 };

SOCKET soc;

if (SUCCEEDED(hr = CreateProcessAndRedirectStdout("/system/bin/getprop", args, soc))) {

errno = 0;

__android_log_print(ANDROID_LOG_INFO, "ServiceCore", "SendConfig>> Reading props");

char pTmp[256000];

int iRet = read(soc, pTmp, sizeof(pTmp));// Read the first few lines

}

...

logcat

I/ServiceCore(20689): CreateProcessAndRedirectStdout>> '/system/bin/getprop(20694)' Created

I/ServiceCore(20689): SendConfig>> Reading props

I/ServiceCore(20694): CreateProcessAndRedirectStdout>> '/system/bin/getprop' started

I/ServiceCore(20694): CreateProcessAndRedirectStdout>> '/system/bin/getprop' newfd:1, oldfd:10

F/libc (20694): Fatal signal 11 (SIGSEGV), code 1, fault addr 0x0 in tid 20694 (getprop)