script: correctly handle buffered "tail" of output. +35 bytes.
This commit is contained in:
Denis Vlasenko
parent
93e1a215af
commit
32fd76c1d5
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@ -13,67 +13,38 @@
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#include "libbb.h"
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struct globals {
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int child_pid;
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int attr_ok; /* NB: 0: ok */
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struct termios tt;
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const char *fname;
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};
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#define G (*ptr_to_globals)
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#define child_pid (G.child_pid)
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#define attr_ok (G.attr_ok )
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#define tt (G.tt )
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#define fname (G.fname )
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#define INIT_G() do { \
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SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
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fname = "typescript"; \
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} while (0)
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static smallint fd_count = 2;
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static void done(void)
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{
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if (child_pid) { /* we are parent */
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if (attr_ok == 0)
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tcsetattr(0, TCSAFLUSH, &tt);
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if (!(option_mask32 & 8)) /* not -q */
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printf("Script done, file is %s\n", fname);
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}
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exit(0);
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}
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#ifdef UNUSED
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static void handle_sigchld(int sig)
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{
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/* wait for the exited child and exit */
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while (wait_any_nohang(&sig) > 0)
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continue;
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done();
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fd_count = 0;
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}
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#endif
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#if ENABLE_GETOPT_LONG
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static const char getopt_longopts[] ALIGN1 =
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"append\0" No_argument "a"
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"command\0" Required_argument "c"
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"flush\0" No_argument "f"
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"quiet\0" No_argument "q"
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;
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#endif
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int script_main(int argc, char *argv[]) MAIN_EXTERNALLY_VISIBLE;
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int script_main(int argc, char *argv[])
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{
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int opt, pty;
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int winsz_ok;
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int opt;
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int mode;
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struct termios rtt;
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int child_pid;
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int attr_ok; /* NB: 0: ok */
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int winsz_ok;
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int pty;
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char pty_line[32];
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struct termios tt, rtt;
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struct winsize win;
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char line[32];
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const char *fname = "typescript";
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const char *shell;
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char shell_opt[] = "-i";
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char *shell_arg = NULL;
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INIT_G();
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#if ENABLE_GETOPT_LONG
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static const char getopt_longopts[] ALIGN1 =
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"append\0" No_argument "a"
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"command\0" Required_argument "c"
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"flush\0" No_argument "f"
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"quiet\0" No_argument "q"
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;
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applet_long_options = getopt_longopts;
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#endif
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opt_complementary = "?1"; /* max one arg */
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@ -95,10 +66,10 @@ int script_main(int argc, char *argv[])
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}
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shell = getenv("SHELL");
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if (shell == NULL) {
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shell = _PATH_BSHELL;
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shell = DEFAULT_SHELL;
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}
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pty = getpty(line, sizeof(line));
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pty = getpty(pty_line, sizeof(pty_line));
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if (pty < 0) {
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bb_perror_msg_and_die("can't get pty");
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}
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@ -112,9 +83,12 @@ int script_main(int argc, char *argv[])
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rtt.c_lflag &= ~ECHO;
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tcsetattr(0, TCSAFLUSH, &rtt);
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/* We exit as soon as child exits */
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//signal(SIGCHLD, handle_sigchld);
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signal(SIGCHLD, (void (*)(int)) done);
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/* "script" from util-linux exits when child exits,
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* we wouldn't wait for EOF from slave pty
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* (output may be produced by grandchildren of child) */
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signal(SIGCHLD, handle_sigchld);
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/* TODO: SIGWINCH? pass window size changes down to slave? */
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child_pid = vfork();
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if (child_pid < 0) {
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@ -123,11 +97,10 @@ int script_main(int argc, char *argv[])
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if (child_pid) {
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/* parent */
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char buf[256];
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#define buf bb_common_bufsiz1
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struct pollfd pfd[2];
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int outfd;
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int fd_count = 2;
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struct pollfd *ppfd = pfd;
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int outfd, count, loop;
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outfd = xopen(fname, mode);
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pfd[0].fd = 0;
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@ -135,14 +108,16 @@ int script_main(int argc, char *argv[])
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pfd[1].fd = pty;
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pfd[1].events = POLLIN;
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ndelay_on(pty); /* this descriptor is not shared, can do this */
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/* ndelay_on(0); - NO, stdin can be shared! */
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/* ndelay_on(0); - NO, stdin can be shared! Pity :( */
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/* copy stdin to pty master input,
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* copy pty master output to stdout and file */
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/* TODO: don't use full_write's, use proper write buffering */
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while (fd_count && safe_poll(ppfd, fd_count, -1) > 0) {
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while (fd_count) {
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/* not safe_poll! we want SIGCHLD to EINTR poll */
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poll(ppfd, fd_count, -1);
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if (pfd[0].revents) {
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int count = safe_read(0, buf, sizeof(buf));
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count = safe_read(0, buf, sizeof(buf));
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if (count <= 0) {
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/* err/eof: don't read anymore */
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pfd[0].revents = 0;
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@ -153,7 +128,6 @@ int script_main(int argc, char *argv[])
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}
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}
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if (pfd[1].revents) {
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int count;
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errno = 0;
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count = safe_read(pty, buf, sizeof(buf));
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if (count <= 0 && errno != EAGAIN) {
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@ -170,14 +144,32 @@ int script_main(int argc, char *argv[])
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}
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}
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}
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done(); /* does not return */
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/* If loop was exited because SIGCHLD handler set fd_count to 0,
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* there still can be some buffered output. But not loop forever:
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* we won't pump orphaned grandchildren's output indefinitely.
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* Testcase: running this in script:
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* exec dd if=/dev/zero bs=1M count=1
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* must have "1+0 records in, 1+0 records out" captured too.
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* (util-linux's script doesn't do this. buggy :) */
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loop = 999;
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/* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
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while (--loop && (count = safe_read(pty, buf, sizeof(buf))) > 0) {
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full_write(1, buf, count);
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full_write(outfd, buf, count);
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}
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if (attr_ok == 0)
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tcsetattr(0, TCSAFLUSH, &tt);
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if (!(opt & 8)) /* not -q */
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printf("Script done, file is %s\n", fname);
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return EXIT_SUCCESS;
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}
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/* child: make pty slave to be input, output, error; run shell */
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close(pty); /* close pty master */
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/* open pty slave to fd 0,1,2 */
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close(0);
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xopen(line, O_RDWR); /* uses fd 0 */
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xopen(pty_line, O_RDWR); /* uses fd 0 */
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xdup2(0, 1);
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xdup2(0, 2);
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/* copy our original stdin tty's parameters to pty */
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