3c0e579a0
Denys Vlasenko
2016-09-13
Subject
less: fall back to using fd #1 for keyboard reading. Closes 9231
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miscutils/less.c+12 -4
| @@ -1797,9 +1797,10 @@ int less_main(int argc, char **argv) | |
| /* Some versions of less can survive w/o controlling tty, | |
| * try to do the same. This also allows to specify an alternative | |
| * tty via "less 1<>TTY". | |
| - | * We don't try to use STDOUT_FILENO directly, |
| + | * |
| + | * We prefer not to use STDOUT_FILENO directly, |
| * since we want to set this fd to non-blocking mode, | |
| - | * and not bother with restoring it on exit. |
| + | * and not interfere with other processes which share stdout with us. |
| */ | |
| tty_name = xmalloc_ttyname(STDOUT_FILENO); | |
| if (tty_name) { | |
| @@ -1811,8 +1812,15 @@ int less_main(int argc, char **argv) | |
| /* Try controlling tty */ | |
| try_ctty: | |
| tty_fd = open(CURRENT_TTY, O_RDONLY); | |
| - | if (tty_fd < 0) |
| - | return bb_cat(argv); |
| + | if (tty_fd < 0) { |
| + | /* |
| + | * If all else fails, less 481 uses stdout. Mimic that. |
| + | * Testcase where usually both ttyname(STDOUT_FILENO) |
| + | * and open(CURRENT_TTY) fail: |
| + | * su -s /bin/sh -c 'busybox less FILE' - nobody |
| + | */ |
| + | tty_fd = STDOUT_FILENO; |
| + | } |
| } | |
| ndelay_on(tty_fd); | |
| kbd_fd = tty_fd; /* save in a global */ | |