32fd76c1d
Denis Vlasenko
2008-02-28
Subject
script: correctly handle buffered "tail" of output. +35 bytes.
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util-linux/script.c+52 -60
| @@ -13,67 +13,38 @@ | |
| #include "libbb.h" | |
| - | struct globals { |
| - | int child_pid; |
| - | int attr_ok; /* NB: 0: ok */ |
| - | struct termios tt; |
| - | const char *fname; |
| - | }; |
| - | #define G (*ptr_to_globals) |
| - | #define child_pid (G.child_pid) |
| - | #define attr_ok (G.attr_ok ) |
| - | #define tt (G.tt ) |
| - | #define fname (G.fname ) |
| - | #define INIT_G() do { \ |
| - | SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \ |
| - | fname = "typescript"; \ |
| - | } while (0) |
| - | |
| - | static void done(void) |
| - | { |
| - | if (child_pid) { /* we are parent */ |
| - | if (attr_ok == 0) |
| - | tcsetattr(0, TCSAFLUSH, &tt); |
| - | if (!(option_mask32 & 8)) /* not -q */ |
| - | printf("Script done, file is %s\n", fname); |
| - | } |
| - | exit(0); |
| - | } |
| + | static smallint fd_count = 2; |
| - | #ifdef UNUSED |
| static void handle_sigchld(int sig) | |
| { | |
| - | /* wait for the exited child and exit */ |
| - | while (wait_any_nohang(&sig) > 0) |
| - | continue; |
| - | done(); |
| + | fd_count = 0; |
| } | |
| - | #endif |
| - | |
| - | #if ENABLE_GETOPT_LONG |
| - | static const char getopt_longopts[] ALIGN1 = |
| - | "append\0" No_argument "a" |
| - | "command\0" Required_argument "c" |
| - | "flush\0" No_argument "f" |
| - | "quiet\0" No_argument "q" |
| - | ; |
| - | #endif |
| int script_main(int argc, char *argv[]) MAIN_EXTERNALLY_VISIBLE; | |
| int script_main(int argc, char *argv[]) | |
| { | |
| - | int opt, pty; |
| - | int winsz_ok; |
| + | int opt; |
| int mode; | |
| - | struct termios rtt; |
| + | int child_pid; |
| + | int attr_ok; /* NB: 0: ok */ |
| + | int winsz_ok; |
| + | int pty; |
| + | char pty_line[32]; |
| + | struct termios tt, rtt; |
| struct winsize win; | |
| - | char line[32]; |
| + | const char *fname = "typescript"; |
| const char *shell; | |
| char shell_opt[] = "-i"; | |
| char *shell_arg = NULL; | |
| - | INIT_G(); |
| #if ENABLE_GETOPT_LONG | |
| + | static const char getopt_longopts[] ALIGN1 = |
| + | "append\0" No_argument "a" |
| + | "command\0" Required_argument "c" |
| + | "flush\0" No_argument "f" |
| + | "quiet\0" No_argument "q" |
| + | ; |
| + | |
| applet_long_options = getopt_longopts; | |
| #endif | |
| opt_complementary = "?1"; /* max one arg */ | |
| @@ -95,10 +66,10 @@ int script_main(int argc, char *argv[]) | |
| } | |
| shell = getenv("SHELL"); | |
| if (shell == NULL) { | |
| - | shell = _PATH_BSHELL; |
| + | shell = DEFAULT_SHELL; |
| } | |
| - | pty = getpty(line, sizeof(line)); |
| + | pty = getpty(pty_line, sizeof(pty_line)); |
| if (pty < 0) { | |
| bb_perror_msg_and_die("can't get pty"); | |
| } | |
| @@ -112,9 +83,12 @@ int script_main(int argc, char *argv[]) | |
| rtt.c_lflag &= ~ECHO; | |
| tcsetattr(0, TCSAFLUSH, &rtt); | |
| - | /* We exit as soon as child exits */ |
| - | //signal(SIGCHLD, handle_sigchld); |
| - | signal(SIGCHLD, (void (*)(int)) done); |
| + | /* "script" from util-linux exits when child exits, |
| + | * we wouldn't wait for EOF from slave pty |
| + | * (output may be produced by grandchildren of child) */ |
| + | signal(SIGCHLD, handle_sigchld); |
| + | |
| + | /* TODO: SIGWINCH? pass window size changes down to slave? */ |
| child_pid = vfork(); | |
| if (child_pid < 0) { | |
| @@ -123,11 +97,10 @@ int script_main(int argc, char *argv[]) | |
| if (child_pid) { | |
| /* parent */ | |
| - | char buf[256]; |
| + | #define buf bb_common_bufsiz1 |
| struct pollfd pfd[2]; | |
| - | int outfd; |
| - | int fd_count = 2; |
| struct pollfd *ppfd = pfd; | |
| + | int outfd, count, loop; |
| outfd = xopen(fname, mode); | |
| pfd[0].fd = 0; | |
| @@ -135,14 +108,16 @@ int script_main(int argc, char *argv[]) | |
| pfd[1].fd = pty; | |
| pfd[1].events = POLLIN; | |
| ndelay_on(pty); /* this descriptor is not shared, can do this */ | |
| - | /* ndelay_on(0); - NO, stdin can be shared! */ |
| + | /* ndelay_on(0); - NO, stdin can be shared! Pity :( */ |
| /* copy stdin to pty master input, | |
| * copy pty master output to stdout and file */ | |
| /* TODO: don't use full_write's, use proper write buffering */ | |
| - | while (fd_count && safe_poll(ppfd, fd_count, -1) > 0) { |
| + | while (fd_count) { |
| + | /* not safe_poll! we want SIGCHLD to EINTR poll */ |
| + | poll(ppfd, fd_count, -1); |
| if (pfd[0].revents) { | |
| - | int count = safe_read(0, buf, sizeof(buf)); |
| + | count = safe_read(0, buf, sizeof(buf)); |
| if (count <= 0) { | |
| /* err/eof: don't read anymore */ | |
| pfd[0].revents = 0; | |
| @@ -153,7 +128,6 @@ int script_main(int argc, char *argv[]) | |
| } | |
| } | |
| if (pfd[1].revents) { | |
| - | int count; |
| errno = 0; | |
| count = safe_read(pty, buf, sizeof(buf)); | |
| if (count <= 0 && errno != EAGAIN) { | |
| @@ -170,14 +144,32 @@ int script_main(int argc, char *argv[]) | |
| } | |
| } | |
| } | |
| - | done(); /* does not return */ |
| + | /* If loop was exited because SIGCHLD handler set fd_count to 0, |
| + | * there still can be some buffered output. But not loop forever: |
| + | * we won't pump orphaned grandchildren's output indefinitely. |
| + | * Testcase: running this in script: |
| + | * exec dd if=/dev/zero bs=1M count=1 |
| + | * must have "1+0 records in, 1+0 records out" captured too. |
| + | * (util-linux's script doesn't do this. buggy :) */ |
| + | loop = 999; |
| + | /* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */ |
| + | while (--loop && (count = safe_read(pty, buf, sizeof(buf))) > 0) { |
| + | full_write(1, buf, count); |
| + | full_write(outfd, buf, count); |
| + | } |
| + | |
| + | if (attr_ok == 0) |
| + | tcsetattr(0, TCSAFLUSH, &tt); |
| + | if (!(opt & 8)) /* not -q */ |
| + | printf("Script done, file is %s\n", fname); |
| + | return EXIT_SUCCESS; |
| } | |
| /* child: make pty slave to be input, output, error; run shell */ | |
| close(pty); /* close pty master */ | |
| /* open pty slave to fd 0,1,2 */ | |
| close(0); | |
| - | xopen(line, O_RDWR); /* uses fd 0 */ |
| + | xopen(pty_line, O_RDWR); /* uses fd 0 */ |
| xdup2(0, 1); | |
| xdup2(0, 2); | |
| /* copy our original stdin tty's parameters to pty */ | |