Mercurial > hg > toybox
view toys/other/w.c @ 1613:96aa7ec74936 draft
Fix yet another sed bug.
The s/// command would copy the \ of substitutions before deciding what to
do with them (generally overwriting the \ with the new data). When the
substitution was A) at the very end of the new string, B) resolved to nothing,
it could leave a trailing \ that didn't belong there and didn't get overwritten
because the "copy trailing data" part that copies the original string's null
terminator already happened before the \ overwrote it.
The ghostwheel() function restarts regexes after embedded NUL bytes, but
if the string it's passed is _longer_ than the length it's told then it
gets confused (and it means we're off the end of our allocation so segfaults
are likely).
Fix: test for \ first and move the "copy byte" logic into an else case.
author | Rob Landley <rob@landley.net> |
---|---|
date | Mon, 15 Dec 2014 03:34:55 -0600 |
parents | 685a0da6ca59 |
children |
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/* w.c - shows logged in users * * Copyright 2012 Gaurang Shastri <gmshastri@gmail.com> USE_W(NEWTOY(w, NULL, TOYFLAG_USR|TOYFLAG_BIN)) config W bool "w" default y depends on TOYBOX_UTMPX help usage: w Show who is logged on and since how long they logged in. */ #include "toys.h" void w_main(void) { struct utmpx *x; xprintf("USER TTY LOGIN@ FROM"); setutxent(); while ((x=getutxent()) != NULL) { if (x->ut_type==7) { time_t tt = x->ut_tv.tv_sec; xprintf("\n%-9.8s%-9.8s %-4.24s (%-1.12s)", x->ut_user, x->ut_line, ctime(&tt), x->ut_host); } } xputc('\n'); }