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#include "../include/Program.h"
#include <unistd.h>
#include <sys/wait.h>
#include <sys/prctl.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#define READ_END 0
#define WRITE_END 1
int exec_program_pipe(const char **args, ReadProgram *read_program) {
/* 1 arguments */
if(args[0] == NULL)
return -1;
int fd[2];
if(pipe(fd) == -1) {
perror("Failed to open pipe");
return -2;
}
pid_t parent_pid = getpid();
pid_t pid = fork();
if(pid == -1) {
perror("Failed to fork");
close(fd[READ_END]);
close(fd[WRITE_END]);
return -3;
} else if(pid == 0) { /* child */
if(prctl(PR_SET_PDEATHSIG, SIGTERM) == -1) {
perror("prctl(PR_SET_PDEATHSIG, SIGTERM) failed");
_exit(127);
}
/* Test if the parent died before the above call to prctl */
if(getppid() != parent_pid)
_exit(127);
dup2(fd[WRITE_END], STDOUT_FILENO);
close(fd[READ_END]);
close(fd[WRITE_END]);
execvp(args[0], (char* const*)args);
perror("execvp");
_exit(127);
} else { /* parent */
close(fd[WRITE_END]);
read_program->pid = pid;
read_program->read_fd = fd[READ_END];
return 0;
}
}
int exec_program(const char **args, ProgramOutputCallback output_callback, void *userdata) {
ReadProgram read_program;
int res = exec_program_pipe(args, &read_program);
if(res != 0)
return res;
int result = 0;
int status;
char buffer[4097];
for(;;) {
ssize_t bytes_read = read(read_program.read_fd, buffer, sizeof(buffer) - 1);
if(bytes_read == 0) {
break;
} else if(bytes_read == -1) {
int err = errno;
fprintf(stderr, "Failed to read from pipe to program %s, error: %s\n", args[0], strerror(err));
result = -err;
break;
}
buffer[bytes_read] = '\0';
if(output_callback) {
result = output_callback(buffer, bytes_read, userdata);
if(result != 0)
break;
}
}
if(result != 0)
kill(read_program.pid, SIGTERM);
if(waitpid(read_program.pid, &status, 0) == -1) {
perror("waitpid failed");
result = -5;
goto cleanup;
}
if(!WIFEXITED(status)) {
result = -4;
goto cleanup;
}
int exit_status = WEXITSTATUS(status);
if(exit_status != 0) {
fprintf(stderr, "Failed to execute program (");
const char **arg = args;
while(*arg) {
if(arg != args)
fputc(' ', stderr);
fprintf(stderr, "'%s'", *arg);
++arg;
}
fprintf(stderr, "), exit status %d\n", exit_status);
result = -exit_status;
}
cleanup:
close(read_program.read_fd);
return result;
}
int wait_program(pid_t process_id) {
int status;
if(waitpid(process_id, &status, 0) == -1) {
perror("waitpid failed");
return -errno;
}
if(!WIFEXITED(status))
return -4;
return WEXITSTATUS(status);
}
int wait_program_non_blocking(pid_t process_id, int *status) {
int s;
int wait_result = waitpid(process_id, &s, WNOHANG);
if(wait_result == -1) {
perror("waitpid failed");
*status = -errno;
return 0;
} else if(wait_result == 0) {
/* the child process is still running */
*status = 0;
return 0;
}
if(!WIFEXITED(s)) {
*status = -4;
return 0;
}
*status = WEXITSTATUS(s);
return 1;
}
int exec_program_async(const char **args, pid_t *result_process_id) {
/* 1 arguments */
if(args[0] == NULL)
return -1;
pid_t parent_pid = getpid();
pid_t pid = fork();
if(pid == -1) {
int err = errno;
perror("Failed to fork");
return -err;
} else if(pid == 0) { /* child */
if(result_process_id) {
if(prctl(PR_SET_PDEATHSIG, SIGTERM) == -1) {
perror("prctl(PR_SET_PDEATHSIG, SIGTERM) failed");
_exit(127);
}
/* Test if the parent died before the above call to prctl */
if(getppid() != parent_pid)
_exit(127);
execvp(args[0], (char* const*)args);
perror("execvp");
_exit(127);
} else {
setsid();
signal(SIGHUP, SIG_IGN);
// TODO: Still creates zombie??? find a fix!
// Daemonize child to make the parent the init process which will reap the zombie child
pid_t second_child = fork();
if(second_child == 0) { // child
execvp(args[0], (char* const*)args);
perror("execvp");
_exit(127);
} else if(second_child != -1) {
_exit(0);
}
}
} else { /* parent */
if(result_process_id)
*result_process_id = pid;
}
return 0;
}
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