8c64e033c
Denis Vlasenko
2009-04-20
Subject
hush: fix stdin of backgrounded pipe
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shell/hush.c +18 -10shell/hush_test/hush-misc/redir5.right +4 -0shell/hush_test/hush-misc/redir5.tests +13 -0
shell/hush.c+18 -10
| @@ -3369,7 +3369,6 @@ static int run_pipe(struct pipe *pi) | |
| static const char *const null_ptr = NULL; | |
| int i; | |
| int nextin; | |
| - | int pipefds[2]; /* pipefds[0] is for reading */ |
| struct command *command; | |
| char **argv_expanded; | |
| char **argv; | |
| @@ -3552,6 +3551,7 @@ static int run_pipe(struct pipe *pi) | |
| nextin = 0; | |
| for (i = 0; i < pi->num_cmds; i++) { | |
| + | struct fd_pair pipefds; |
| #if !BB_MMU | |
| volatile nommu_save_t nommu_save; | |
| nommu_save.new_env = NULL; | |
| @@ -3568,10 +3568,10 @@ static int run_pipe(struct pipe *pi) | |
| } | |
| /* pipes are inserted between pairs of commands */ | |
| - | pipefds[0] = 0; |
| - | pipefds[1] = 1; |
| + | pipefds.rd = 0; |
| + | pipefds.wr = 1; |
| if ((i + 1) < pi->num_cmds) | |
| - | xpipe(pipefds); |
| + | xpiped_pair(pipefds); |
| command->pid = BB_MMU ? fork() : vfork(); | |
| if (!command->pid) { /* child */ | |
| @@ -3592,10 +3592,18 @@ static int run_pipe(struct pipe *pi) | |
| } | |
| } | |
| #endif | |
| - | xmove_fd(nextin, 0); |
| - | xmove_fd(pipefds[1], 1); /* write end */ |
| - | if (pipefds[0] > 1) |
| - | close(pipefds[0]); /* read end */ |
| + | if (pi->alive_cmds == 0 && pi->followup == PIPE_BG) { |
| + | /* 1st cmd in backgrounded pipe |
| + | * should have its stdin /dev/null'ed */ |
| + | close(0); |
| + | if (open(bb_dev_null, O_RDONLY)) |
| + | xopen("/", O_RDONLY); |
| + | } else { |
| + | xmove_fd(nextin, 0); |
| + | } |
| + | xmove_fd(pipefds.wr, 1); |
| + | if (pipefds.rd > 1) |
| + | close(pipefds.rd); |
| /* Like bash, explicit redirects override pipes, | |
| * and the pipe fd is available for dup'ing. */ | |
| if (setup_redirects(command, NULL)) | |
| @@ -3640,9 +3648,9 @@ static int run_pipe(struct pipe *pi) | |
| if (i) | |
| close(nextin); | |
| if ((i + 1) < pi->num_cmds) | |
| - | close(pipefds[1]); /* write end */ |
| + | close(pipefds.wr); |
| /* Pass read (output) pipe end to next iteration */ | |
| - | nextin = pipefds[0]; |
| + | nextin = pipefds.rd; |
| } | |
| if (!pi->alive_cmds) { | |
shell/hush_test/hush-misc/redir5.right+4 -0
| @@ -0,0 +1,4 @@ | |
| + | Backgrounded pipes shall have their stdin redirected to /dev/null |
| + | Zero:0 |
| + | Zero:0 |
| + | Done |
shell/hush_test/hush-misc/redir5.tests+13 -0
| @@ -0,0 +1,13 @@ | |
| + | echo "Backgrounded pipes shall have their stdin redirected to /dev/null" |
| + | |
| + | # 1. bash does not redirect stdin to /dev/null if it is interactive. |
| + | # hush does it always (this is allowed by standards). |
| + | |
| + | # 2. Failure will result in this script hanging |
| + | |
| + | cat & wait; echo Zero:$? |
| + | |
| + | # This does not work for bash! bash bug? |
| + | cat | cat & wait; echo Zero:$? |
| + | |
| + | echo Done |