websh/websh.c

199 lines
3.3 KiB
C

/**
* @file websh.c
* @date 2018-04-16
*
* @brief Formats program output for the web.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <sys/wait.h>
#define MAX_LEN 256
static const char *pname;
static int eFlag = 0;
static int hFlag = 0;
static int sFlag = 0;
static const char *word;
static const char *tag;
volatile sig_atomic_t quit = 0;
static void handle_signal(int signal)
{
quit = 1;
}
void usage(void)
{
fprintf(stderr, "Usage: websh [-e] [-h] [-s WORD:TAG]\n");
exit(EXIT_FAILURE);
}
void parsesArg(char *sArg)
{
char *token;
int i = 0;
while ((token = strsep(&sArg, ":"))) {
if (strcmp(token, "") == 0)
usage();
if (i == 2)
usage();
if (i == 0) {
word = token;
} else {
tag = token;
}
i++;
}
}
void parse(int argc, char *argv[])
{
int optInd = 0;
char *sArg;
while ((optInd = getopt(argc, argv, "ehs:")) != -1) {
switch (optInd) {
case 'e':
if (eFlag != 0) {
usage();
} else {
eFlag = 1;
}
break;
case 'h':
if (hFlag != 0) {
usage();
} else {
hFlag = 1;
}
break;
case 's':
if (sFlag != 0) {
usage();
} else {
sFlag = 1;
sArg = optarg;
parsesArg(sArg);
}
break;
case '?':
usage();
default:
assert(0);
}
}
pname = argv[0];
}
void child2(int fd[], char readbuffer[])
{
/* CHILD TWO */
close(fd[1]);
int nbytes = read(fd[0], readbuffer, MAX_LEN);
if (nbytes == -1) {
perror(pname);
exit(EXIT_FAILURE);
}
printf("%s", readbuffer);
return;
}
void child1(int fd[], char *line)
{
/* CHILD ONE */
close(fd[0]);
dup2(fd[1], STDOUT_FILENO);
execl("/bin/bash", "/bin/bash", "-c", line, (char *) NULL);
fprintf(stderr, "[%s] exec failed\n", pname);
free(line);
exit(EXIT_FAILURE);
return;
}
int main(int argc, char *argv[])
{
parse(argc, argv);
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = handle_signal;
sigaction(SIGINT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
while (quit == 0) {
char *line = NULL;
size_t len = 0;
ssize_t nread;
char readbuffer[MAX_LEN];
int status;
int w;
if (eFlag)
printf("<html><head></head><body>\n");
int fd[2];
pid_t childpid1;
pid_t childpid2;
pipe(fd);
while ((nread = getline(&line, &len, stdin)) > 0) {
childpid1 = fork();
if (childpid1 > 0) {
/* PARENT ONE */
childpid2 = fork();
if (childpid2 > 0) {
/* PARENT TWO */
} else if (childpid2 == 0) {
/* CHILD TWO */
child2(fd, readbuffer);
} else {
perror(pname);
free(line);
exit(EXIT_FAILURE);
}
do {
w = waitpid(childpid2, &status, WUNTRACED | WCONTINUED);
if (w == -1) {
perror(pname);
exit(EXIT_FAILURE);
}
if (WIFSIGNALED(status)) {
printf("Killed by signal %d\n", WTERMSIG(status));
} else if (WIFSTOPPED(status)) {
printf("Stopped by signal %d\n", WSTOPSIG(status));
} else if (WIFCONTINUED(status)) {
printf("Continued\n");
}
} while (!WIFEXITED(status) && !WIFSIGNALED(status));
} else if (childpid1 == 0) {
/* CHILD ONE */
child1(fd, line);
} else {
perror(pname);
free(line);
exit(EXIT_FAILURE);
}
}
free(line);
break;
}
return 0;
}