diff options
Diffstat (limited to 'src/utils/squish-unix.c')
| -rw-r--r-- | src/utils/squish-unix.c | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/src/utils/squish-unix.c b/src/utils/squish-unix.c new file mode 100644 index 0000000..9d9aa42 --- /dev/null +++ b/src/utils/squish-unix.c @@ -0,0 +1,354 @@ +#define _GNU_SOURCE 1 +#include <errno.h> +#include <fcntl.h> +#include <signal.h> +#include <stdarg.h> +#include <stdbool.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <stropts.h> +#include <sys/ioctl.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <sys/socket.h> +#include <sys/un.h> +#include <termios.h> +#include <unistd.h> + + +/* AF_LOCAL is not defined on solaris */ +#if !defined(AF_LOCAL) +#define AF_LOCAL AF_UNIX +#endif +#if !defined(PF_LOCAL) +#define PF_LOCAL PF_UNIX +#endif + + +/* solaris doesn't have SUN_LEN */ +//#ifndef SUN_LEN +//#define SUN_LEN(sa) ( strlen((sa)->sun_path) + \ +// (size_t)(((struct sockaddr_un*)0)->sun_path) ) +//#endif + +static void +fail_io (const char *msg, ...) + __attribute__ ((noreturn)) + __attribute__ ((format (printf, 1, 2))); + +/* Prints MSG, formatting as with printf(), + plus an error message based on errno, + and exits. */ +static void +fail_io (const char *msg, ...) +{ + va_list args; + + va_start (args, msg); + vfprintf (stderr, msg, args); + va_end (args); + + if (errno != 0) + fprintf (stderr, ": %s", strerror (errno)); + putc ('\n', stderr); + exit (EXIT_FAILURE); +} + +/* If FD is a terminal, configures it for noncanonical input mode + with VMIN and VTIME set as indicated. + If FD is not a terminal, has no effect. */ +static void +make_noncanon (int fd, int vmin, int vtime) +{ + if (isatty (fd)) + { + struct termios termios; + if (tcgetattr (fd, &termios) < 0) + fail_io ("tcgetattr"); + termios.c_lflag &= ~(ICANON | ECHO); + termios.c_cc[VMIN] = vmin; + termios.c_cc[VTIME] = vtime; + if (tcsetattr (fd, TCSANOW, &termios) < 0) + fail_io ("tcsetattr"); + } +} + +/* Make FD non-blocking if NONBLOCKING is true, + or blocking if NONBLOCKING is false. */ +static void +make_nonblocking (int fd, bool nonblocking) +{ + int flags = fcntl (fd, F_GETFL); + if (flags < 0) + fail_io ("fcntl"); + if (nonblocking) + flags |= O_NONBLOCK; + else + flags &= ~O_NONBLOCK; + if (fcntl (fd, F_SETFL, flags) < 0) + fail_io ("fcntl"); +} + +/* Handle a read or write on *FD, which is the socket if + FD_IS_SOCK is true, that returned end-of-file or error + indication RETVAL. The system call is named CALL, for use in + error messages. Returns true if processing may continue, + false if we're all done. */ +static bool +handle_error (ssize_t retval, int *fd, bool fd_is_sock, const char *call) +{ + if (retval == 0) + { + if (fd_is_sock) + return false; + else + { + *fd = -1; + return true; + } + } + else + fail_io (call); +} + +/* Copies data from stdin to SOCK and from SOCK to stdout until no + more data can be read or written. */ +static void +relay (int sock) +{ + struct pipe + { + int in, out; + char buf[BUFSIZ]; + size_t size, ofs; + bool active; + }; + struct pipe pipes[2]; + + /* In case stdin is a file, go back to the beginning. + This allows replaying the input on reset. */ + lseek (STDIN_FILENO, 0, SEEK_SET); + + /* Make SOCK, stdin, and stdout non-blocking. */ + make_nonblocking (sock, true); + make_nonblocking (STDIN_FILENO, true); + make_nonblocking (STDOUT_FILENO, true); + + /* Configure noncanonical mode on stdin to avoid waiting for + end-of-line. */ + make_noncanon (STDIN_FILENO, 1, 0); + + memset (pipes, 0, sizeof pipes); + pipes[0].in = STDIN_FILENO; + pipes[0].out = sock; + pipes[1].in = sock; + pipes[1].out = STDOUT_FILENO; + + while (pipes[0].in != -1 || pipes[1].in != -1 + || (pipes[1].size && pipes[1].out != -1)) + { + fd_set read_fds, write_fds; + sigset_t empty_set; + int retval; + int i; + + FD_ZERO (&read_fds); + FD_ZERO (&write_fds); + for (i = 0; i < 2; i++) + { + struct pipe *p = &pipes[i]; + + /* Don't do anything with the stdin->sock pipe until we + have some data for the sock->stdout pipe. If we get + too eager, vmplayer will throw away our input. */ + if (i == 0 && !pipes[1].active) + continue; + + if (p->in != -1 && p->size + p->ofs < sizeof p->buf) + FD_SET (p->in, &read_fds); + if (p->out != -1 && p->size > 0) + FD_SET (p->out, &write_fds); + } + sigemptyset (&empty_set); + retval = pselect (FD_SETSIZE, &read_fds, &write_fds, NULL, NULL, + &empty_set); + if (retval < 0) + { + if (errno == EINTR) + { + /* Child died. Do final relaying. */ + struct pipe *p = &pipes[1]; + if (p->out == -1) + exit (0); + make_nonblocking (STDOUT_FILENO, false); + for (;;) + { + ssize_t n; + + /* Write buffer. */ + while (p->size > 0) + { + n = write (p->out, p->buf + p->ofs, p->size); + if (n < 0) + fail_io ("write"); + else if (n == 0) + fail_io ("zero-length write"); + p->ofs += n; + p->size -= n; + } + p->ofs = 0; + + p->size = n = read (p->in, p->buf, sizeof p->buf); + if (n <= 0) + exit (0); + } + } + fail_io ("select"); + } + + for (i = 0; i < 2; i++) + { + struct pipe *p = &pipes[i]; + if (p->in != -1 && FD_ISSET (p->in, &read_fds)) + { + ssize_t n = read (p->in, p->buf + p->ofs + p->size, + sizeof p->buf - p->ofs - p->size); + if (n > 0) + { + p->active = true; + p->size += n; + if (p->size == BUFSIZ && p->ofs != 0) + { + memmove (p->buf, p->buf + p->ofs, p->size); + p->ofs = 0; + } + } + else if (!handle_error (n, &p->in, p->in == sock, "read")) + return; + } + if (p->out != -1 && FD_ISSET (p->out, &write_fds)) + { + ssize_t n = write (p->out, p->buf + p->ofs, p->size); + if (n > 0) + { + p->ofs += n; + p->size -= n; + if (p->size == 0) + p->ofs = 0; + } + else if (!handle_error (n, &p->out, p->out == sock, "write")) + return; + } + } + } +} + +static void +sigchld_handler (int signo __attribute__ ((unused))) +{ + /* Nothing to do. */ +} + +int +main (int argc __attribute__ ((unused)), char *argv[]) +{ + pid_t pid; + struct itimerval zero_itimerval; + struct sockaddr_un vsun; + sigset_t sigchld_set; + int sock; + + if (argc < 3) + { + fprintf (stderr, + "usage: squish-unix SOCKET COMMAND [ARG]...\n" + "Squishes both stdin and stdout into a single Unix domain\n" + "socket named SOCKET, and runs COMMAND as a subprocess.\n"); + return EXIT_FAILURE; + } + + /* Create socket. */ + sock = socket (PF_LOCAL, SOCK_STREAM, 0); + if (sock < 0) + fail_io ("socket"); + + /* Configure socket. */ + vsun.sun_family = AF_LOCAL; + strncpy (vsun.sun_path, argv[1], sizeof vsun.sun_path); + vsun.sun_path[sizeof vsun.sun_path - 1] = '\0'; + if (unlink (vsun.sun_path) < 0 && errno != ENOENT) + fail_io ("unlink"); + if (bind (sock, (struct sockaddr *) &vsun, + (offsetof (struct sockaddr_un, sun_path) + + strlen (vsun.sun_path) + 1)) < 0) + fail_io ("bind"); + + /* Listen on socket. */ + if (listen (sock, 1) < 0) + fail_io ("listen"); + + /* Block SIGCHLD and set up a handler for it. */ + sigemptyset (&sigchld_set); + sigaddset (&sigchld_set, SIGCHLD); + if (sigprocmask (SIG_BLOCK, &sigchld_set, NULL) < 0) + fail_io ("sigprocmask"); + if (signal (SIGCHLD, sigchld_handler) == SIG_ERR) + fail_io ("signal"); + + /* Save the virtual interval timer, which might have been set + by the process that ran us. It really should be applied to + our child process. */ + memset (&zero_itimerval, 0, sizeof zero_itimerval); + if (setitimer (ITIMER_VIRTUAL, &zero_itimerval, NULL) < 0) + fail_io ("setitimer"); + + pid = fork (); + if (pid < 0) + fail_io ("fork"); + else if (pid != 0) + { + /* Running in parent process. */ + make_nonblocking (sock, true); + for (;;) + { + fd_set read_fds; + sigset_t empty_set; + int retval; + int conn; + + /* Wait for connection. */ + FD_ZERO (&read_fds); + FD_SET (sock, &read_fds); + sigemptyset (&empty_set); + retval = pselect (sock + 1, &read_fds, NULL, NULL, NULL, &empty_set); + if (retval < 0) + { + if (errno == EINTR) + break; + fail_io ("select"); + } + + /* Accept connection. */ + conn = accept (sock, NULL, NULL); + if (conn < 0) + fail_io ("accept"); + + /* Relay connection. */ + relay (conn); + close (conn); + } + return 0; + } + else + { + /* Running in child process. */ + if (close (sock) < 0) + fail_io ("close"); + execvp (argv[2], argv + 2); + fail_io ("exec"); + } +} |