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diff -urpN busybox-1.15.1/shell/hush.c busybox-1.15.1-hush/shell/hush.c
--- busybox-1.15.1/shell/hush.c 2009-09-12 17:56:20.000000000 +0200
+++ busybox-1.15.1-hush/shell/hush.c 2009-09-23 03:27:27.000000000 +0200
@@ -5183,6 +5183,47 @@ static FILE *generate_stream_from_string
xmove_fd(channel[1], 1);
/* Prevent it from trying to handle ctrl-z etc */
IF_HUSH_JOB(G.run_list_level = 1;)
+ /* Awful hack for `trap` or $(trap).
+ *
+ * http://www.opengroup.org/onlinepubs/009695399/utilities/trap.html
+ * contains an example where "trap" is executed in a subshell:
+ *
+ * save_traps=$(trap)
+ * ...
+ * eval "$save_traps"
+ *
+ * Standard does not say that "trap" in subshell shall print
+ * parent shell's traps. It only says that its output
+ * must have suitable form, but then, in the above example
+ * (which is not supposed to be normative), it implies that.
+ *
+ * bash (and probably other shell) does implement it
+ * (traps are reset to defaults, but "trap" still shows them),
+ * but as a result, "trap" logic is hopelessly messed up:
+ *
+ * # trap
+ * trap -- 'echo Ho' SIGWINCH <--- we have a handler
+ * # (trap) <--- trap is in subshell - no output (correct, traps are reset)
+ * # true | trap <--- trap is in subshell - no output (ditto)
+ * # echo `true | trap` <--- in subshell - output (but traps are reset!)
+ * trap -- 'echo Ho' SIGWINCH
+ * # echo `(trap)` <--- in subshell in subshell - output
+ * trap -- 'echo Ho' SIGWINCH
+ * # echo `true | (trap)` <--- in subshell in subshell in subshell - output!
+ * trap -- 'echo Ho' SIGWINCH
+ *
+ * The rules when to forget and when to not forget traps
+ * get really complex and nonsensical.
+ *
+ * Our solution: ONLY bare $(trap) or `trap` is special.
+ */
+ s = skip_whitespace(s);
+ if (strncmp(s, "trap", 4) == 0 && (*skip_whitespace(s + 4) == '\0'))
+ {
+ static const char *const argv[] = { NULL, NULL };
+ builtin_trap((char**)argv);
+ exit(0); /* not _exit() - we need to fflush */
+ }
#if BB_MMU
reset_traps_to_defaults();
parse_and_run_string(s);
@@ -7057,7 +7098,8 @@ static int FAST_FUNC builtin_trap(char *
if (G.traps[i]) {
printf("trap -- ");
print_escaped(G.traps[i]);
- printf(" %s\n", get_signame(i));
+ /* bash compat: it says SIGxxx, not just xxx */
+ printf(" SIG%s\n", get_signame(i));
}
}
/*fflush(stdout); - done after each builtin anyway */
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