[git commit master] hush: fix handling of empty arguments
Denys Vlasenko
vda.linux at googlemail.com
Sun Oct 18 09:46:35 UTC 2009
commit: http://git.busybox.net/busybox/commit/?id=f37eb3999bce2ea46fef0214e33279b81609e596
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master
function old new delta
builtin_exec 25 83 +58
parse_stream 2242 2261 +19
run_pipe 1782 1787 +5
static.pseudo_null_str - 3 +3
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 3/0 up/down: 85/0) Total: 85 bytes
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
shell/hush.c | 43 ++++++++++++++++++++-------
shell/hush_test/hush-misc/empty_args.right | 6 ++++
shell/hush_test/hush-misc/empty_args.tests | 9 +++++
shell/hush_test/hush-psubst/emptytick.right | 7 +++-
shell/hush_test/hush-psubst/emptytick.tests | 8 ++++-
5 files changed, 58 insertions(+), 15 deletions(-)
create mode 100644 shell/hush_test/hush-misc/empty_args.right
create mode 100755 shell/hush_test/hush-misc/empty_args.tests
diff --git a/shell/hush.c b/shell/hush.c
index 1d2826d..46bb7e9 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2185,7 +2185,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
ored_ch = 0;
- debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
+ debug_printf_expand("expand_vars_to_list: arg:'%s' or_mask:%x\n", arg, or_mask);
debug_print_list("expand_vars_to_list", output, n);
n = o_save_ptr(output, n);
debug_print_list("expand_vars_to_list[0]", output, n);
@@ -3425,7 +3425,7 @@ static void pseudo_exec_argv(nommu_save_t *nommu_save,
sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
execvp(argv[0], argv);
bb_perror_msg("can't execute '%s'", argv[0]);
- _exit(EXIT_FAILURE);
+ _exit(127); /* bash compat */
}
/* Called after [v]fork() in run_pipe
@@ -3895,7 +3895,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
}
- /* if someone gives us an empty string: ``, $(), ... */
+ /* if someone gives us an empty string: `cmd with empty output` */
if (!argv_expanded[0]) {
debug_leave();
return 0;
@@ -5802,7 +5802,7 @@ static int parse_stream_dquoted(o_string *as_string,
if (ch != '\n') {
next = i_peek(input);
}
- debug_printf_parse(": ch=%c (%d) escape=%d\n",
+ debug_printf_parse("\" ch=%c (%d) escape=%d\n",
ch, ch, dest->o_escape);
if (ch == '\\') {
if (next == EOF) {
@@ -5882,6 +5882,11 @@ static struct pipe *parse_stream(char **pstring,
end_trigger ? end_trigger : 'X');
debug_enter();
+ /* If very first arg is "" or '', dest.data may end up NULL.
+ * Preventing this: */
+ o_addchr(&dest, '\0');
+ dest.length = 0;
+
G.ifs = get_local_var_value("IFS");
if (G.ifs == NULL)
G.ifs = " \t\n";
@@ -6979,16 +6984,32 @@ static int FAST_FUNC builtin_cd(char **argv)
static int FAST_FUNC builtin_exec(char **argv)
{
- if (*++argv == NULL)
- return EXIT_SUCCESS; /* bash does this */
- {
+ static const char pseudo_null_str[] = { SPECIAL_VAR_SYMBOL, SPECIAL_VAR_SYMBOL, '\0' };
+ char **pp = argv;
#if !BB_MMU
- nommu_save_t dummy;
+ nommu_save_t dummy;
#endif
- /* TODO: if exec fails, bash does NOT exit! We do... */
- pseudo_exec_argv(&dummy, argv, 0, NULL);
- /* never returns */
+
+ if (*++argv == NULL)
+ return EXIT_SUCCESS; /* bash does this */
+
+ /* Make sure empty arguments aren't ignored */
+ /* Example: exec ls '' */
+ pp = argv;
+ while (*pp) {
+ if ((*pp)[0] == '\0')
+ *pp = (char*)pseudo_null_str;
+ pp++;
}
+
+ /* Careful: we can end up here after [v]fork. Do not restore
+ * tty pgrp then, only top-level shell process does that */
+ if (G_saved_tty_pgrp && getpid() == G.root_pid)
+ tcsetpgrp(G_interactive_fd, G_saved_tty_pgrp);
+
+ /* TODO: if exec fails, bash does NOT exit! We do... */
+ pseudo_exec_argv(&dummy, argv, 0, NULL);
+ /* never returns */
}
static int FAST_FUNC builtin_exit(char **argv)
diff --git a/shell/hush_test/hush-misc/empty_args.right b/shell/hush_test/hush-misc/empty_args.right
new file mode 100644
index 0000000..38ed8b8
--- /dev/null
+++ b/shell/hush_test/hush-misc/empty_args.right
@@ -0,0 +1,6 @@
+Null 0th arg:
+hush: can't execute '': No such file or directory
+127
+Null 1st arg:
+0
+Null arg in exec:
diff --git a/shell/hush_test/hush-misc/empty_args.tests b/shell/hush_test/hush-misc/empty_args.tests
new file mode 100755
index 0000000..efce549
--- /dev/null
+++ b/shell/hush_test/hush-misc/empty_args.tests
@@ -0,0 +1,9 @@
+echo Null 0th arg:
+""
+echo $?
+echo Null 1st arg:
+# printf without args would print usage info
+printf ""
+echo $?
+echo Null arg in exec:
+exec printf ""
diff --git a/shell/hush_test/hush-psubst/emptytick.right b/shell/hush_test/hush-psubst/emptytick.right
index d4b70c5..1f60ecf 100644
--- a/shell/hush_test/hush-psubst/emptytick.right
+++ b/shell/hush_test/hush-psubst/emptytick.right
@@ -1,14 +1,17 @@
0
0
+hush: can't execute '': No such file or directory
0
+hush: can't execute '': No such file or directory
0
0
0
0
0
+hush: can't execute '': No such file or directory
0
+hush: can't execute '': No such file or directory
0
0
0
-0
-0
+hush: can't execute '': No such file or directory
diff --git a/shell/hush_test/hush-psubst/emptytick.tests b/shell/hush_test/hush-psubst/emptytick.tests
index af3a183..a269f02 100755
--- a/shell/hush_test/hush-psubst/emptytick.tests
+++ b/shell/hush_test/hush-psubst/emptytick.tests
@@ -1,16 +1,20 @@
true; ``; echo $?
false; ``; echo $?
+# UNFIXED BUG. bash sets $? to 127:
true; `""`; echo $?
+# bash sets $? to 127:
false; `""`; echo $?
true; ` `; echo $?
false; ` `; echo $?
true; $(); echo $?
false; $(); echo $?
+# bash sets $? to 127:
true; $(""); echo $?
+# bash sets $? to 127:
false; $(""); echo $?
true; $( ); echo $?
false; $( ); echo $?
-true; exec ''; echo $?
-false; exec ''; echo $?
+exec ''; echo $?
+echo Not reached
--
1.6.3.3
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