mirror of https://github.com/leahneukirchen/mblaze
mshow: actually filter the parts
parent
5d1266b38f
commit
be2ca1ba42
@ -0,0 +1,124 @@
|
||||
#include <poll.h>
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
#include <sys/wait.h>
|
||||
#include <unistd.h>
|
||||
|
||||
int
|
||||
filter(char *input, size_t inlen, char *cmd, char **outputo, size_t *outleno)
|
||||
{
|
||||
char *output;
|
||||
size_t outlen;
|
||||
ssize_t outalloc = 4096;
|
||||
pid_t pid;
|
||||
|
||||
output = malloc(outalloc);
|
||||
outlen = 0;
|
||||
|
||||
int pipe0[2];
|
||||
int pipe1[2];
|
||||
|
||||
if (pipe(pipe0) != 0 || pipe(pipe1) != 0)
|
||||
goto fail;
|
||||
|
||||
char *argv[] = { "/bin/sh", "-c", cmd, (char *)0 };
|
||||
|
||||
if (!(pid = fork())) {
|
||||
dup2(pipe0[0], 0);
|
||||
close(pipe0[1]);
|
||||
close(pipe0[0]);
|
||||
|
||||
dup2(pipe1[1], 1);
|
||||
close(pipe1[0]);
|
||||
close(pipe1[1]);
|
||||
|
||||
execvp(argv[0], argv);
|
||||
exit(-1);
|
||||
}
|
||||
close(pipe0[0]);
|
||||
close(pipe1[1]);
|
||||
|
||||
if (pid < 0) {
|
||||
close(pipe0[1]);
|
||||
close(pipe1[0]);
|
||||
goto fail;
|
||||
}
|
||||
|
||||
struct pollfd fds[2];
|
||||
|
||||
fds[0].fd = pipe1[0];
|
||||
fds[0].events = POLLIN;
|
||||
fds[1].fd = pipe0[1];
|
||||
fds[1].events = POLLOUT;
|
||||
|
||||
while ((fds[0].fd >= 0 || fds[1].fd >= 0) &&
|
||||
poll(fds, sizeof fds / sizeof fds[0], -1) >= 0) {
|
||||
if (fds[0].revents & POLLIN) {
|
||||
if (outlen + 512 > outalloc) {
|
||||
outalloc *= 2;
|
||||
if (outalloc < 0)
|
||||
exit(-1);
|
||||
output = realloc(output, outalloc);
|
||||
if (!output)
|
||||
exit(-1);
|
||||
}
|
||||
ssize_t ret = read(fds[0].fd, output + outlen, 512);
|
||||
if (ret > 0)
|
||||
outlen += ret;
|
||||
else if (ret < 0)
|
||||
close(fds[0].fd);
|
||||
} else if (fds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
|
||||
fds[0].fd = -1;
|
||||
}
|
||||
|
||||
if (fds[1].revents & POLLOUT) {
|
||||
ssize_t ret = write(fds[1].fd, input, inlen);
|
||||
if (ret > 0) {
|
||||
input += ret;
|
||||
inlen -= ret;
|
||||
}
|
||||
if (ret <= 0 || inlen == 0)
|
||||
close(fds[1].fd);
|
||||
} else if (fds[1].revents & (POLLERR | POLLHUP | POLLNVAL)) {
|
||||
fds[1].fd = -1;
|
||||
}
|
||||
}
|
||||
|
||||
// ok to fail when closed already
|
||||
close(pipe0[1]);
|
||||
close(pipe1[0]);
|
||||
|
||||
int status;
|
||||
waitpid(pid, &status, 0);
|
||||
|
||||
*outputo = output;
|
||||
*outleno = outlen;
|
||||
|
||||
return WEXITSTATUS(status);
|
||||
|
||||
fail:
|
||||
*outputo = 0;
|
||||
*outleno = 0;
|
||||
|
||||
return -1;
|
||||
}
|
||||
|
||||
#ifdef TEST
|
||||
int
|
||||
main()
|
||||
{
|
||||
char *input = "foo\nbar\nbaz";
|
||||
int e;
|
||||
|
||||
char *output;
|
||||
size_t outlen;
|
||||
|
||||
e = filter(input, strlen(input), "rev;exit 2", &output, &outlen);
|
||||
|
||||
fwrite(output, 1, outlen, stdout);
|
||||
printf("%ld -> %d\n", outlen, e);
|
||||
|
||||
return 0;
|
||||
}
|
||||
#endif
|
Loading…
Reference in New Issue