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#include "process.h"
#include <fcntl.h>
#include <sys/wait.h>
#include <signal.h>
struct Process {
pid_t pid;
int pipe;
char error[64];
};
bool process_run(Process *proc, char const *command) {
memset(proc, 0, sizeof *proc);
bool success = false;
int pipefd[2];
if (pipe(pipefd) == 0) {
pid_t pid = fork();
if (pid == 0) {
// child process
// put child in its own group. it will be in this group with all of its descendents,
// so by killing everything in the group, we kill all the descendents of this process.
// if we didn't do this, we would just be killing the sh process in process_kill.
setpgid(0, 0);
// send stdout and stderr to pipe
dup2(pipefd[1], STDOUT_FILENO);
dup2(pipefd[1], STDERR_FILENO);
close(pipefd[0]);
close(pipefd[1]);
char *program = "/bin/sh";
char *argv[] = {program, "-c", (char *)command, NULL};
if (execv(program, argv) == -1) {
dprintf(STDERR_FILENO, "%s: %s\n", program, strerror(errno));
exit(127);
}
} else if (pid > 0) {
// parent process
close(pipefd[1]);
fcntl(pipefd[0], F_SETFL, fcntl(pipefd[0], F_GETFL) | O_NONBLOCK); // set pipe to non-blocking
proc->pid = pid;
proc->pipe = pipefd[0];
success = true;
}
} else {
strbuf_printf(proc->error, "%s", strerror(errno));
}
return success;
}
char const *process_geterr(Process *p) {
return *p->error ? p->error : NULL;
}
long long process_read(Process *proc, char *data, size_t size) {
assert(proc->pipe);
ssize_t bytes_read = read(proc->pipe, data, size);
if (bytes_read >= 0) {
return (long long)bytes_read;
} else if (errno == EAGAIN) {
return -1;
} else {
strbuf_printf(proc->error, "%s", strerror(errno));
return -2;
}
}
void process_kill(Process *proc) {
kill(-proc->pid, SIGKILL); // kill everything in process group
// get rid of zombie process
waitpid(proc->pid, NULL, 0);
close(proc->pipe);
proc->pid = 0;
proc->pipe = 0;
}
int process_check_status(Process *proc, char *message, size_t message_size) {
int wait_status = 0;
int ret = waitpid(proc->pid, &wait_status, WNOHANG);
if (ret == 0) {
// process still running
return 0;
} else if (ret > 0) {
if (WIFEXITED(wait_status)) {
close(proc->pipe); proc->pipe = 0;
int code = WEXITSTATUS(wait_status);
if (code == 0) {
str_printf(message, message_size, "exited successfully");
return +1;
} else {
str_printf(message, message_size, "exited with code %d", code);
return -1;
}
} else if (WIFSIGNALED(wait_status)) {
close(proc->pipe);
str_printf(message, message_size, "terminated by signal %d", WTERMSIG(wait_status));
return -1;
}
return 0;
} else {
// this process is gone or something?
close(proc->pipe); proc->pipe = 0;
str_printf(message, message_size, "process ended unexpectedly");
return -1;
}
}
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