mc/src/pipethrough.c

451 lines
12 KiB
C

/*
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
Roland Illig <roland.illig@gmx.de>, 2004.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h> /* On Solaris, FD_SET invokes memset(3) */
#include <sys/types.h>
#include <sys/time.h>
#include <sys/wait.h>
#ifdef HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
#include <unistd.h>
#include "pipethrough.h"
#define PIPE_RD 0
#define PIPE_WR 1
/* Internal data types *************************************************/
struct writer_buffer {
/*@temp@*/ const void *data;
size_t size;
size_t pos;
int fd;
int lasterror;
};
struct reader_buffer {
/*@null@*/ /*@only@*/ void *data;
size_t size;
size_t maxsize;
int fd;
int lasterror;
};
struct select_request {
int n;
fd_set readfds;
fd_set writefds;
};
/* Helper functions ****************************************************/
static int closeref(int *fd)
/*@globals internalState, fileSystem, errno; @*/
/*@modifies internalState, fileSystem, errno, *fd; @*/
{
int result = close(*fd);
*fd = -1;
return result;
}
static void propagate(int *dest, int src)
/*@modifies *dest; @*/
{
if (*dest == 0) {
*dest = src;
}
}
/* reader_buffer -- implementation *************************************/
static void reader_buffer_init(/*@out@*/ struct reader_buffer *buf, int fd)
/*@modifies *buf; @*/
{
buf->data = NULL;
buf->size = 0;
buf->maxsize = 0;
buf->fd = fd;
buf->lasterror = 0;
}
/* SPlint cannot describe realloc(3) correctly. */
/*@-usereleased@*/ /*@-compdef@*/ /*@-branchstate@*/ /*@-compmempass@*/
static ssize_t reader_buffer_read(struct reader_buffer *buf)
/*@globals internalState, errno; @*/
/*@modifies internalState, errno, *buf; @*/
{
ssize_t res;
if (buf->size == buf->maxsize) {
size_t newsize = buf->maxsize + 4096;
/*@only@*/ void *newdata;
if (buf->data == NULL) {
newdata = malloc(newsize);
} else {
newdata = realloc(buf->data, newsize);
}
if (newdata == NULL) {
return (ssize_t) -1;
}
buf->data = newdata;
newdata = NULL;
buf->maxsize = newsize;
}
res = read(buf->fd, &(((char *) buf->data)[buf->size]),
buf->maxsize - buf->size);
if (res == (ssize_t) -1) {
return res;
}
buf->size += (ssize_t) res;
return res;
}
/*@=usereleased@*/ /*@=compdef@*/ /*@=branchstate@*/ /*@=compmempass@*/
static void reader_buffer_handle(struct reader_buffer *buf)
/*@globals internalState, fileSystem, errno; @*/
/*@modifies internalState, fileSystem, errno, *buf; @*/
{
ssize_t rd = reader_buffer_read(buf);
if (rd == (ssize_t) -1) {
propagate(&buf->lasterror, errno);
}
if (rd <= 0) {
if (closeref(&(buf->fd)) == -1) {
propagate(&buf->lasterror, errno);
}
}
}
/*@-mustfreeonly@*/
static void reader_buffer_finalize(/*@special@*/ struct reader_buffer *buf)
/*@modifies *buf; @*/
/*@releases buf->data; @*/
{
if (buf->data != NULL) {
free(buf->data);
buf->data = NULL;
}
buf->size = 0;
buf->maxsize = 0;
buf->fd = -1;
}
/*@=mustfreeonly@*/
/* writer_buffer -- implementation *************************************/
static void writer_buffer_init(/*@out@*/ struct writer_buffer *buf, int fd,
const void *data, size_t size)
/*@globals internalState, fileSystem, errno; @*/
/*@modifies internalState, fileSystem, errno, *buf; @*/
{
buf->fd = fd;
buf->data = data;
buf->size = size;
buf->pos = 0;
buf->lasterror = 0;
if (size == 0) {
if (closeref(&(buf->fd)) == -1) {
propagate(&buf->lasterror, errno);
}
}
}
static void writer_buffer_handle(struct writer_buffer *buf)
/*@globals internalState, fileSystem, errno; @*/
/*@modifies internalState, fileSystem, errno, *buf; @*/
{
typedef void (*my_sighandler_fn) (int);
my_sighandler_fn old_sigpipe = signal(SIGPIPE, SIG_IGN);
ssize_t wr = write(buf->fd, &(((const char *) buf->data)[buf->pos]),
buf->size - buf->pos);
if (wr == (ssize_t) -1) {
propagate(&buf->lasterror, errno);
} else {
buf->pos += wr;
}
if (wr == (ssize_t) -1 || buf->pos == buf->size) {
if (closeref(&(buf->fd)) == -1) {
propagate(&buf->lasterror, errno);
}
}
(void) signal(SIGPIPE, old_sigpipe);
}
static void writer_buffer_finalize(/*@special@*/ struct writer_buffer *buf)
/*@modifies *buf; @*/
{
buf->data = NULL;
buf->size = 0;
buf->pos = 0;
buf->fd = -1;
}
/* select_request -- implementation ************************************/
static void select_request_init(/*@out@*/ struct select_request *sr)
/*@modifies *sr; @*/
{
FD_ZERO(&(sr->readfds));
FD_ZERO(&(sr->writefds));
sr->n = 0;
}
static void select_request_add_reader(struct select_request *sr,
const struct reader_buffer *buf)
/*@modifies *sr; @*/
{
if (buf->fd != -1) {
FD_SET(buf->fd, &(sr->readfds));
if (buf->fd + 1 > sr->n) {
sr->n = buf->fd + 1;
}
}
}
static void select_request_add_writer(struct select_request *sr,
const struct writer_buffer *buf)
/*@modifies *sr; @*/
{
if (buf->fd != -1) {
FD_SET(buf->fd, &(sr->writefds));
if (buf->fd + 1 > sr->n) {
sr->n = buf->fd + 1;
}
}
}
static void select_request_handle_writer(const struct select_request *sr,
struct writer_buffer *buf)
/*@globals internalState, fileSystem, errno; @*/
/*@modifies internalState, fileSystem, errno, *buf; @*/
{
if (buf->fd != -1 && FD_ISSET(buf->fd, &(sr->writefds))) {
writer_buffer_handle(buf);
}
}
static void select_request_handle_reader(const struct select_request *sr,
struct reader_buffer *buf)
/*@globals internalState, fileSystem, errno; @*/
/*@modifies internalState, fileSystem, errno, *buf; @*/
{
if (buf->fd != -1 && FD_ISSET(buf->fd, &(sr->readfds))) {
reader_buffer_handle(buf);
}
}
/* pipethrough -- helper functions *************************************/
static void pipethrough_child(const char *command,
const int *stdin_pipe,
const int *stdout_pipe,
const int *stderr_pipe)
/*@globals internalState, fileSystem, errno, stderr; @*/
/*@modifies internalState, fileSystem, errno, *stderr; @*/
{
const char *shell = getenv("SHELL");
if (shell == NULL) {
shell = "/bin/sh";
}
if (close(STDIN_FILENO) == -1
|| dup2(stdin_pipe[PIPE_RD], STDIN_FILENO) == -1
|| close(stdin_pipe[PIPE_RD]) == -1
|| close(stdin_pipe[PIPE_WR]) == -1
|| close(STDOUT_FILENO) == -1
|| dup2(stdout_pipe[PIPE_WR], STDOUT_FILENO) == -1
|| close(stdout_pipe[PIPE_RD]) == -1
|| close(stdout_pipe[PIPE_WR]) == -1
|| close(STDERR_FILENO) == -1
|| dup2(stderr_pipe[PIPE_WR], STDERR_FILENO) == -1
|| close(stderr_pipe[PIPE_RD]) == -1
|| close(stderr_pipe[PIPE_WR]) == -1
|| execl(shell, shell, "-c", command, NULL) == -1) {
perror("pipethrough_child");
(void) fflush(stderr);
_exit(EXIT_FAILURE);
}
}
static int pipethrough_parent(int stdin_fd,
int stdout_fd,
int stderr_fd,
const struct pipe_inbuffer *stdin_buf,
/*@out@*/ struct pipe_outbuffer *stdout_buf,
/*@out@*/ struct pipe_outbuffer *stderr_buf)
/*@globals internalState, fileSystem, errno; @*/
/*@modifies internalState, fileSystem, errno,
*stdout_buf, *stderr_buf; @*/
{
struct writer_buffer stdin_wbuf;
struct reader_buffer stdout_rbuf;
struct reader_buffer stderr_rbuf;
struct select_request sr;
int select_res;
int firsterror;
firsterror = 0;
writer_buffer_init(&stdin_wbuf, stdin_fd, stdin_buf->data,
stdin_buf->size);
propagate(&firsterror, stdin_wbuf.lasterror);
reader_buffer_init(&stdout_rbuf, stdout_fd);
propagate(&firsterror, stdout_rbuf.lasterror);
reader_buffer_init(&stderr_rbuf, stderr_fd);
propagate(&firsterror, stdout_rbuf.lasterror);
while (stdin_wbuf.fd != -1 || stdout_rbuf.fd != -1
|| stderr_rbuf.fd != -1) {
select_request_init(&sr);
retry_select:
select_request_add_writer(&sr, &stdin_wbuf);
select_request_add_reader(&sr, &stdout_rbuf);
select_request_add_reader(&sr, &stderr_rbuf);
select_res = select(sr.n, &(sr.readfds), &(sr.writefds),
NULL, NULL);
if (select_res == -1) {
if (errno == EINTR) {
goto retry_select;
} else {
propagate(&firsterror, errno);
goto cleanup_select;
}
}
select_request_handle_writer(&sr, &stdin_wbuf);
propagate(&firsterror, stdin_wbuf.lasterror);
select_request_handle_reader(&sr, &stdout_rbuf);
propagate(&firsterror, stdout_rbuf.lasterror);
select_request_handle_reader(&sr, &stderr_rbuf);
propagate(&firsterror, stdout_rbuf.lasterror);
}
stdout_buf->data = stdout_rbuf.data;
stdout_rbuf.data = NULL;
stdout_buf->size = stdout_rbuf.size;
stderr_buf->data = stderr_rbuf.data;
stderr_rbuf.data = NULL;
stderr_buf->size = stderr_rbuf.size;
return 0;
cleanup_select:
writer_buffer_finalize(&stdin_wbuf);
reader_buffer_finalize(&stdout_rbuf);
reader_buffer_finalize(&stderr_rbuf);
errno = firsterror;
return -1;
}
/* pipethrough -- implementation ***************************************/
extern int pipethrough(const char *command,
const struct pipe_inbuffer *stdin_buf,
/*@out@*/ struct pipe_outbuffer *stdout_buf,
/*@out@*/ struct pipe_outbuffer *stderr_buf,
/*@out@*/ int *status)
/*@globals internalState, fileSystem, errno, stderr; @*/
/*@modifies internalState, fileSystem, errno, *stderr,
*stdout_buf, *stderr_buf, *status; @*/
{
int retval = -1;
pid_t pid;
int stdin_pipe[2] = { -1, -1 };
int stdout_pipe[2] = { -1, -1 };
int stderr_pipe[2] = { -1, -1 };
int firsterror = 0;
if (pipe(stdin_pipe) == -1
|| pipe(stdout_pipe) == -1
|| pipe(stderr_pipe) == -1) {
propagate(&firsterror, errno);
goto cleanup;
}
if ((pid = fork()) == (pid_t) -1) {
propagate(&firsterror, errno);
goto cleanup;
}
if (pid == 0) {
pipethrough_child(command, stdin_pipe, stdout_pipe,
stderr_pipe);
/*@notreached@*/
}
if (closeref(&stdin_pipe[PIPE_RD]) == -1
|| closeref(&stdout_pipe[PIPE_WR]) == -1
|| closeref(&stderr_pipe[PIPE_WR]) == -1) {
propagate(&firsterror, errno);
goto cleanup;
}
if (pipethrough_parent(stdin_pipe[PIPE_WR], stdout_pipe[PIPE_RD],
stderr_pipe[PIPE_RD], stdin_buf,
stdout_buf, stderr_buf) == -1) {
propagate(&firsterror, errno);
} else {
retval = 0;
}
/*@-branchstate@*/
if (waitpid(pid, status, 0) == (pid_t) -1) {
propagate(&firsterror, errno);
pipe_outbuffer_finalize(stdout_buf);
pipe_outbuffer_finalize(stderr_buf);
retval = -1;
}
/*@=branchstate@*/
cleanup:
(void) close(stderr_pipe[PIPE_RD]);
(void) close(stderr_pipe[PIPE_WR]);
(void) close(stdout_pipe[PIPE_RD]);
(void) close(stdout_pipe[PIPE_WR]);
(void) close(stdin_pipe[PIPE_RD]);
(void) close(stdin_pipe[PIPE_WR]);
if (retval == -1) {
errno = firsterror;
}
return retval;
}
/* pipe_outbuffer -- implementation ************************************/
/*@-mustfreeonly@*/ /*@-nullstate@*/
extern void pipe_outbuffer_finalize(struct pipe_outbuffer *buf)
/*@modifies *buf; @*/
/*@releases buf->data; @*/
/*@ensures isnull buf->data; @*/
{
if (buf->data != NULL) {
free(buf->data);
buf->data = NULL;
}
buf->size = 0;
}
/*@=mustfreeonly@*/ /*@=nullstate@*/