我想创建一个子进程,向子进程发送命令“LISTALL”。子进程应该发出系统命令ps并将其列表返回给父进程。然后,父进程应该选择一个进程并将其杀死。这是我到目前为止的代码,但我在尝试运行时遇到了问题。
#include <stdio.h>
#include <unistd.h>
#include <cstring>
#include <stdlib.h>
#include <iostream>
#include <sys/wait.h>
char* getlistOfProcesses(const char* cmd)
{
FILE* pipe = popen(cmd, "r");
if (!pipe) return (char*)"ERROR";
char buffer[128];
char *result = new char[1024];
while(!feof(pipe)) {
if(fgets(buffer, 128, pipe) != NULL)
strcat(result, buffer);
}
pclose(pipe);
return result;
}
int spawnGEdit()
{
pid_t gPid = fork();
if(gPid == 0)
{
execl("gedit", "gedit", NULL);
exit(-1);
}
else
{
}
return 0;
}
int main(int argc, char **argv)
{
int P2C[2];
int C2P[2];
pipe(P2C);
pipe(C2P);
pid_t cPid = fork();
char cmd[50];
char* listOfProcesses = new char[1024];
spawnGEdit();
if (cPid == 0)
{
close(P2C[1]);
close(C2P[0]);
read(P2C[0], cmd, 10);
if(strcmp(cmd,"LISTALL") == 0)
{
write(C2P[1], getlistOfProcesses("ps"), 1024);
close(P2C[0]);
close(C2P[1]);
}
}
else if (cPid > 0)
{
close(C2P[1]);
close(P2C[0]);
write(P2C[1], "LISTALL", 10);
wait(NULL);
read(C2P[0], listOfProcesses,1024);
printf("%s",listOfProcesses);
//TODO
//get user input of a PID
//kill the PID
close(C2P[0]);
close(P2C[1]);
}
else
{
// fork failed
printf("Forking failed!\n");
exit(1);
}
return 0;
}
当我尝试编译它时,我遇到了以下错误:
/tmp/cciTPIOZ.o: In function `getlistOfProcesses(char const*)':
test.cpp:(.text+0x53): undefined reference to `operator new[](unsigned long)'
/tmp/cciTPIOZ.o: In function `main':
test.cpp:(.text+0x166): undefined reference to `operator new[](unsigned long)'
/tmp/cciTPIOZ.o: In function `__static_initialization_and_destruction_0(int, int)':
test.cpp:(.text+0x2c0): undefined reference to `std::ios_base::Init::Init()'
test.cpp:(.text+0x2cf): undefined reference to `std::ios_base::Init::~Init()'
collect2: error: ld returned 1 exit status
我正在使用以下编译器:
cc test.cpp -o test
popen
的文档,您会发现它被声明为:FILE *popen(const char *command, const char *mode)
。其中command
是一个const char *
,但您有一个std::string
。这些不是相同的数据类型。在您的cmd
上调用.c_str()
可能是您需要的(尽管我认为您有更多的错误)。 - Cornstalks