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Added piped process support to Util::Procs

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This commit is contained in:
Thulinma 2011-10-12 23:30:42 +02:00
parent 1a2719b01f
commit 3634a627f1
2 changed files with 87 additions and 20 deletions
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99
util/proc.cpp
View file

@ -24,22 +24,11 @@ void Util::Procs::childsig_handler(int signum){
plist.erase(ret);
}
/// Starts a new process if the name is not already active.
/// \return 0 if process was not started, process PID otherwise.
/// \arg name Name for this process - only used internally.
/// \arg cmd Commandline for this process.
pid_t Util::Procs::Start(std::string name, std::string cmd){
if (isActive(name)){return getPid(name);}
if (!handler_set){
struct sigaction new_action;
new_action.sa_handler = Util::Procs::childsig_handler;
sigemptyset(&new_action.sa_mask);
new_action.sa_flags = 0;
sigaction(SIGCHLD, &new_action, NULL);
handler_set = true;
}
pid_t ret = fork();
if (ret == 0){
/// Attempts to run the command cmd.
/// Replaces the current process - use after forking first!
/// This function will never return - it will either run the given
/// command or kill itself with return code 42.
void Util::Procs::runCmd(std::string & cmd){
//split cmd into arguments
//supports a maximum of 20 arguments
char * tmp = (char*)cmd.c_str();
@ -57,9 +46,28 @@ pid_t Util::Procs::Start(std::string name, std::string cmd){
//execute the command
execvp(args[0], args);
#if DEBUG >= 1
std::cerr << "Error: " << strerror(errno) << std::endl;
std::cerr << "Error running \"" << cmd << "\": " << strerror(errno) << std::endl;
#endif
_exit(42);
}
/// Starts a new process if the name is not already active.
/// \return 0 if process was not started, process PID otherwise.
/// \arg name Name for this process - only used internally.
/// \arg cmd Commandline for this process.
pid_t Util::Procs::Start(std::string name, std::string cmd){
if (isActive(name)){return getPid(name);}
if (!handler_set){
struct sigaction new_action;
new_action.sa_handler = Util::Procs::childsig_handler;
sigemptyset(&new_action.sa_mask);
new_action.sa_flags = 0;
sigaction(SIGCHLD, &new_action, NULL);
handler_set = true;
}
pid_t ret = fork();
if (ret == 0){
runCmd(cmd);
}else{
if (ret > 0){
#if DEBUG >= 1
@ -76,6 +84,63 @@ pid_t Util::Procs::Start(std::string name, std::string cmd){
return ret;
}
/// Starts two piped processes if the name is not already active.
/// \return 0 if process was not started, main (receiving) process PID otherwise.
/// \arg name Name for this process - only used internally.
/// \arg cmd Commandline for sub (sending) process.
/// \arg cmd2 Commandline for main (receiving) process.
pid_t Util::Procs::Start(std::string name, std::string cmd, std::string cmd2){
if (isActive(name)){return getPid(name);}
if (!handler_set){
struct sigaction new_action;
new_action.sa_handler = Util::Procs::childsig_handler;
sigemptyset(&new_action.sa_mask);
new_action.sa_flags = 0;
sigaction(SIGCHLD, &new_action, NULL);
handler_set = true;
}
pid_t ret = fork();
if (ret == 0){
int pfildes[2];
if (pipe(pfildes) == -1){
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. Pipe creation failed." << std::endl;
#endif
_exit(41);
}
pid_t pid;
if ((pid = fork()) == -1){
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. Second fork() failed." << std::endl;
#endif
_exit(41);
}else if (pid == 0){
close(pfildes[0]);
dup2(pfildes[1],1);
close(pfildes[1]);
runCmd(cmd);
}else{
close(pfildes[1]);
dup2(pfildes[0],0);
close(pfildes[0]);
runCmd(cmd2);
}
}else{
if (ret > 0){
#if DEBUG >= 1
std::cerr << "Process " << name << " started, PID " << ret << ": " << cmd << " | " << cmd2 << std::endl;
#endif
plist.insert(std::pair<pid_t, std::string>(ret, name));
}else{
#if DEBUG >= 1
std::cerr << "Process " << name << " could not be started. fork() failed." << std::endl;
#endif
return 0;
}
}
return ret;
}
/// Stops the named process, if running.
/// \arg name (Internal) name of process to stop
void Util::Procs::Stop(std::string name){

2
util/proc.h
View file

@ -14,8 +14,10 @@ namespace Util{
static std::map<pid_t, std::string> plist; ///< Holds active processes
static bool handler_set; ///< If true, the sigchld handler has been setup.
static void childsig_handler(int signum);
static void runCmd(std::string & cmd);
public:
static pid_t Start(std::string name, std::string cmd);
static pid_t Start(std::string name, std::string cmd, std::string cmd2);
static void Stop(std::string name);
static void Stop(pid_t name);
static void StopAll();