Я создаю интерактивную веб-страницу, чтобы пользователь мог вводить команду Bash на HTML-странице, нажимать кнопку «Выполнить», и выходные данные будут отображаться на той же странице.
На данный момент мой сервер может работатькоманды, если они помещены в строку поиска, но она не работает для конвейера или флагов, просто основные команды.
Мне нужна помощь, чтобы понять, почему pexec.c ниже не обеспечивает вывод, только пустое значениестр.
**wrc-server.c**
/*
** server.c -- a stream socket server demo
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>
#include <poll.h>
#define PORT "3838" // The port users will be connecting to
#define BACKLOG 10 // How many pending connections queue will hold
void sigchld_handler(int s)
{
(void)s; // Quiet unused variable warning
// waitpid() might overwrite errno, so we save and restore it:
int saved_errno = errno;
while(waitpid(-1, NULL, WNOHANG) > 0);
errno = saved_errno;
}
// Get sockaddr, IPv4 or IPv6:
void *get_in_addr(struct sockaddr *sa)
{
if (sa->sa_family == AF_INET) {
return &(((struct sockaddr_in*)sa)->sin_addr);
}
return &(((struct sockaddr_in6*)sa)->sin6_addr);
}
char *parse(char *command) {
char * newCommand = (char *) malloc(sizeof(char)*35);
newCommand = strtok(command, " ");
newCommand = strtok(NULL, "/ ");
return newCommand;
}
char * execution(char *command) {
//printf("yo:%s\n", command);
int piper[2];
size_t len = 0;
pipe(piper);
char* output = malloc(1000 * sizeof(char));
memset(output, '\0', 1000* sizeof(char));
pid_t pid = fork();
if(pid != 0) // Parent
{
wait(NULL);
close(piper[1]);
int n = sizeof(output);
// ----Rob Code
struct pollfd * poll_fd = malloc(sizeof(struct pollfd));
poll_fd->fd = piper[0];
poll_fd->events = POLLIN;
//wait(NULL);
//printf("done\n");
//printf("AAA %s", output);
if (poll(poll_fd, 1, 0) == 1) { // Pipe data check
read(piper[0], output, 1000);
}
//printf("the command is %s\n", output);
//read(&output, output, piper[0]);
//printf("%s\n", piper[0]);
//dup2(piper[1], 1);
//close(0)
}
else {
//dup2(piper[1], 1);
//printf("run: %s", command);
close(1);
dup(piper[1]);
//close(0);
execlp(command, command, NULL);
exit(1);
}
// dup2 execute and print it out in parent
// if (*(commands+1) != NULL) // Redirect stdout as long as were not at the last row
// {
// dup2(piper[1], 1);
// close(piper[0]);
// }
return output;
}
int main(void)
{
int sockfd, new_fd; // Listen on sock_fd, new connection on new_fd
struct addrinfo hints, *servinfo, *p;
struct sockaddr_storage their_addr; // Connector's address information
socklen_t sin_size;
struct sigaction sa;
int yes = 1;
char s[INET6_ADDRSTRLEN];
int rv;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE; // use my IP
if ((rv = getaddrinfo(NULL, PORT, &hints, &servinfo)) != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
return 1;
}
// Loop through all the results and bind to the first we can
for(p = servinfo; p != NULL; p = p->ai_next) {
if ((sockfd = socket(p->ai_family, p->ai_socktype,
p->ai_protocol)) == -1) {
perror("server: socket");
continue;
}
if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes,
sizeof(int)) == -1) {
perror("setsockopt");
exit(1);
}
if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
close(sockfd);
perror("server: bind");
continue;
}
break;
}
//printf("%s\n", servinfo.ai_canonname);
freeaddrinfo(servinfo); // All done with this structure
if (p == NULL) {
fprintf(stderr, "server: failed to bind\n");
exit(1);
}
if (listen(sockfd, BACKLOG) == -1) {
perror("listen");
exit(1);
}
printf("server: waiting for connections...\n");
int ptds[2];
char *commands = malloc(sizeof(char)*1212);
while(1) { // Main accept() loop
sin_size = sizeof their_addr;
new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size);
if (new_fd == -1) {
perror("accept");
continue;
}
inet_ntop(their_addr.ss_family,
get_in_addr((struct sockaddr *)&their_addr),
s, sizeof s);
printf("server: got connection from %s\n", s);
char *buf = malloc(1000*sizeof(char));
memset(buf, '\0', 1000* sizeof(char));
recv(new_fd, buf, 1000*sizeof(char), 0);
//printf("%s\n", parse(buf));
;
if (!fork()) { // This is the child process
close(sockfd); // Child doesn't need the listener
if (send(new_fd, execution(parse(buf)), 1000, 0) == -1)
perror("send");
close(new_fd);
exit(0);
}
close(new_fd);
}
return 0;
}
**pexec.c**
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
static char* args[512];
pid_t pid;
int command_pipe[2];
#define READ 0
#define WRITE 1
static int command(int input, int first, int last)
{
int pipettes[2];
pipe(pipettes);
pid = fork();
if (pid == 0) {
if (first == 1 && last == 0 && input == 0) {
// First command
dup2(pipettes[WRITE], STDOUT_FILENO);
} else if (first == 0 && last == 0 && input != 0) {
// Middle command
dup2(input, STDIN_FILENO);
dup2(pipettes[WRITE], STDOUT_FILENO);
} else {
// Last command
dup2(input, STDIN_FILENO);
}
if (execvp( args[0], args) == -1)
_exit(EXIT_FAILURE);
}
if (input != 0)
close(input);
close(pipettes[WRITE]);
if (last == 1)
close(pipettes[READ]);
return pipettes[READ];
}
static void cleanup(int n)
{
int i;
for (i = 0; i < n; ++i)
wait(NULL);
}
static int run(char* cmd, int input, int first, int last);
static char line[1024];
static int n = 0; /* Number of calls to 'command' */
int main(int argc, char *argv[])
{
while (1) {
// for(int i = 1; i < argc; i++) {
// strcat(line, argv[i]);
// strcat(line, " ");
// }
/* Read a command line */
//if (!fgets(line, 1024, stdin))
//return 0;
int InputLength = atoi(getenv("INPUT_LENGTH"));
fread(line, InputLength, 1, stdin);
int input = 0;
int first = 1;
char* cmd = line;
char* next = strchr(cmd, '@'); /* Find first '|' */
while (next != NULL) {
/* 'next' points to '|' */
*next = '\0';
input = run(cmd, input, first, 0);
cmd = next + 1;
next = strchr(cmd, '@'); /* Find next '|' */
first = 0;
}
input = run(cmd, input, first, 1);
cleanup(n);
n = 0;
}
return 0;
}
static void split(char* cmd);
static int run(char* cmd, int input, int first, int last)
{
split(cmd);
if (args[0] != NULL) {
if (strcmp(args[0], "exit") == 0)
exit(0);
n += 1;
return command(input, first, last);
}
return 0;
}
static char* skipwhite(char* s)
{
while (isspace(*s))
++s;
return s;
}
static void split(char* cmd)
{
cmd = skipwhite(cmd);
char* next = strchr(cmd, ' ');
int i = 0;
while (next != NULL) {
next[0] = '\0';
args[i] = cmd;
++i;
cmd = skipwhite(next + 1);
next = strchr(cmd, ' ');
}
if (cmd[0] != '\0') {
args[i] = cmd;
next = strchr(cmd, '\n');
next[0] = '\0';
++i;
}
args[i] = NULL;
}