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#include "../include/Process.hpp"
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <sys/wait.h>
#include <limits.h>
#include <fcntl.h>
#include <dirent.h>
#include <stdlib.h>
#define PIPE_READ 0
#define PIPE_WRITE 1
namespace gsr {
static void debug_print_args(const char **args) {
fprintf(stderr, "gsr-ui info: running command:");
while(*args) {
fprintf(stderr, " %s", *args);
++args;
}
fprintf(stderr, "\n");
}
static bool is_number(const char *str) {
for(int i = 0; str[i]; ++i) {
char c = str[i];
if(c < '0' || c > '9')
return false;
}
return true;
}
bool exec_program_daemonized(const char **args) {
/* 1 argument */
if(args[0] == nullptr)
return false;
debug_print_args(args);
const pid_t pid = vfork();
if(pid == -1) {
perror("Failed to vfork");
return false;
} else if(pid == 0) { /* child */
setsid();
signal(SIGHUP, SIG_IGN);
// Daemonize child to make the parent the init process which will reap the zombie child
const pid_t second_child = vfork();
if(second_child == 0) { // child
execvp(args[0], (char* const*)args);
perror("execvp");
_exit(127);
} else if(second_child != -1) {
// TODO:
_exit(0);
}
} else { /* parent */
waitpid(pid, nullptr, 0);
}
return true;
}
pid_t exec_program(const char **args, int *read_fd) {
if(read_fd)
*read_fd = -1;
/* 1 argument */
if(args[0] == nullptr)
return -1;
int fds[2] = {-1, -1};
if(pipe(fds) == -1)
return -1;
debug_print_args(args);
const pid_t pid = vfork();
if(pid == -1) {
close(fds[PIPE_READ]);
close(fds[PIPE_WRITE]);
perror("Failed to vfork");
return -1;
} else if(pid == 0) { /* child */
dup2(fds[PIPE_WRITE], STDOUT_FILENO);
close(fds[PIPE_READ]);
close(fds[PIPE_WRITE]);
execvp(args[0], (char* const*)args);
perror("execvp");
_exit(127);
} else { /* parent */
close(fds[PIPE_WRITE]);
if(read_fd)
*read_fd = fds[PIPE_READ];
else
close(fds[PIPE_READ]);
return pid;
}
}
int exec_program_get_stdout(const char **args, std::string &result) {
result.clear();
int read_fd = -1;
const pid_t process_id = exec_program(args, &read_fd);
if(process_id == -1)
return -1;
int exit_status = 0;
char buffer[8192];
for(;;) {
ssize_t bytes_read = read(read_fd, buffer, sizeof(buffer));
if(bytes_read == 0) {
break;
} else if(bytes_read == -1) {
fprintf(stderr, "Failed to read from pipe to program %s, error: %s\n", args[0], strerror(errno));
exit_status = -1;
break;
}
buffer[bytes_read] = '\0';
result.append(buffer, bytes_read);
}
if(exit_status != 0)
kill(process_id, SIGKILL);
int status = 0;
if(waitpid(process_id, &status, 0) == -1) {
perror("waitpid failed");
exit_status = -1;
}
if(!WIFEXITED(status))
exit_status = -1;
if(exit_status == 0)
exit_status = WEXITSTATUS(status);
close(read_fd);
return exit_status;
}
// |output_buffer| should be at least PATH_MAX in size
bool read_cmdline_arg0(const char *filepath, char *output_buffer, int output_buffer_size) {
output_buffer[0] = '\0';
const char *arg0_end = NULL;
int fd = open(filepath, O_RDONLY);
if(fd == -1)
return false;
char buffer[PATH_MAX];
ssize_t bytes_read = read(fd, buffer, sizeof(buffer));
if(bytes_read == -1)
goto err;
arg0_end = (const char*)memchr(buffer, '\0', bytes_read);
if(!arg0_end)
goto err;
if((arg0_end - buffer) + 1 <= output_buffer_size) {
memcpy(output_buffer, buffer, arg0_end - buffer);
output_buffer[arg0_end - buffer] = '\0';
close(fd);
return true;
}
err:
close(fd);
return false;
}
pid_t pidof(const char *process_name) {
pid_t result = -1;
DIR *dir = opendir("/proc");
if(!dir)
return -1;
char cmdline_filepath[PATH_MAX];
char arg0[PATH_MAX];
struct dirent *entry;
while((entry = readdir(dir)) != NULL) {
if(!is_number(entry->d_name))
continue;
snprintf(cmdline_filepath, sizeof(cmdline_filepath), "/proc/%s/cmdline", entry->d_name);
if(read_cmdline_arg0(cmdline_filepath, arg0, sizeof(arg0)) && strcmp(process_name, arg0) == 0) {
result = atoi(entry->d_name);
break;
}
}
closedir(dir);
return result;
}
}
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