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hush: fix handling of empty arguments

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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@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-10-18 11:46:35 +02:00
parent 7673e7fda4
commit f37eb3999b
5 changed files with 62 additions and 19 deletions
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43
shell/hush.c
View File

@ -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)
{
static const char pseudo_null_str[] = { SPECIAL_VAR_SYMBOL, SPECIAL_VAR_SYMBOL, '\0' };
char **pp = argv;
#if !BB_MMU
nommu_save_t dummy;
#endif
if (*++argv == NULL)
return EXIT_SUCCESS; /* bash does this */
{
#if !BB_MMU
nommu_save_t dummy;
#endif
/* TODO: if exec fails, bash does NOT exit! We do... */
pseudo_exec_argv(&dummy, argv, 0, NULL);
/* never returns */
/* 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)

6
shell/hush_test/hush-misc/empty_args.right Normal file
View File

@ -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:

9
shell/hush_test/hush-misc/empty_args.tests Executable file
View File

@ -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 ""

15
shell/hush_test/hush-psubst/emptytick.right
View File

@ -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
0
0
0
0
hush: can't execute '': No such file or directory

8
shell/hush_test/hush-psubst/emptytick.tests
View File

@ -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