[git commit master 1/1] hush: fix multimple dependent variable expansion cases
Denys Vlasenko
vda.linux at googlemail.com
Fri Jul 16 11:52:32 UTC 2010
commit: http://git.busybox.net/busybox/commit/?id=29082231d0cb1a5b327de5d515b16f332d4dbdaf
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master
function old new delta
get_local_var_value 100 171 +71
expand_assignments 46 76 +30
reset_traps_to_defaults 229 238 +9
maybe_set_to_sigexit 47 50 +3
init_sigmasks 211 214 +3
builtin_trap 462 465 +3
expand_vars_to_list 2412 2408 -4
run_pipe 1568 1533 -35
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 6/2 up/down: 119/-39) Total: 80 bytes
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
shell/hush.c | 108 ++++++++++++++++++++-------
shell/hush_test/hush-vars/var_serial.right | 5 ++
shell/hush_test/hush-vars/var_serial.tests | 22 ++++++
3 files changed, 107 insertions(+), 28 deletions(-)
create mode 100644 shell/hush_test/hush-vars/var_serial.right
create mode 100755 shell/hush_test/hush-vars/var_serial.tests
diff --git a/shell/hush.c b/shell/hush.c
index c67aebd..c5a8ea6 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -221,7 +221,8 @@
//config: default y
//config: depends on HUSH
//config: help
-//config: This instructs hush to print commands before execution. Adds ~300 bytes.
+//config: This instructs hush to print commands before execution.
+//config: Adds ~300 bytes.
//config:
//usage:#define hush_trivial_usage NOUSAGE_STR
@@ -664,7 +665,7 @@ struct globals {
smallint n_mode;
#if ENABLE_HUSH_MODE_X
smallint x_mode;
-# define G_x_mode G.x_mode
+# define G_x_mode (G.x_mode)
#else
# define G_x_mode 0
#endif
@@ -688,6 +689,7 @@ struct globals {
const char *cwd;
struct variable *top_var; /* = &G.shell_ver (set in main()) */
struct variable shell_ver;
+ char **expanded_assignments;
#if ENABLE_HUSH_FUNCTIONS
struct function *top_func;
# if ENABLE_HUSH_LOCAL
@@ -1459,9 +1461,23 @@ static struct variable *get_local_var(const char *name)
static const char* FAST_FUNC get_local_var_value(const char *name)
{
- struct variable **pp = get_ptr_to_local_var(name);
- if (pp)
- return strchr((*pp)->varstr, '=') + 1;
+ struct variable **vpp;
+
+ if (G.expanded_assignments) {
+ char **cpp = G.expanded_assignments;
+ int len = strlen(name);
+ while (*cpp) {
+ char *cp = *cpp;
+ if (strncmp(cp, name, len) == 0 && cp[len] == '=')
+ return cp + len + 1;
+ cpp++;
+ }
+ }
+
+ vpp = get_ptr_to_local_var(name);
+ if (vpp)
+ return strchr((*vpp)->varstr, '=') + 1;
+
if (strcmp(name, "PPID") == 0)
return utoa(G.root_ppid);
// bash compat: UID? EUID?
@@ -3090,11 +3106,14 @@ static char* expand_strvec_to_string(char **argv)
static char **expand_assignments(char **argv, int count)
{
int i;
- char **p = NULL;
+ char **p;
+
+ G.expanded_assignments = p = NULL;
/* Expand assignments into one string each */
for (i = 0; i < count; i++) {
- p = add_string_to_strings(p, expand_string_to_string(argv[i]));
+ G.expanded_assignments = p = add_string_to_strings(p, expand_string_to_string(argv[i]));
}
+ G.expanded_assignments = NULL;
return p;
}
@@ -4316,6 +4335,27 @@ static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
* backgrounded: cmd & { list } &
* subshell: ( list ) [&]
*/
+#if !ENABLE_HUSH_MODE_X
+#define redirect_and_varexp_helper(new_env_p, old_vars_p, command, squirrel, char argv_expanded) \
+ redirect_and_varexp_helper(new_env_p, old_vars_p, command, squirrel)
+#endif
+static int redirect_and_varexp_helper(char ***new_env_p, struct variable **old_vars_p, struct command *command, int squirrel[3], char **argv_expanded)
+{
+ /* setup_redirects acts on file descriptors, not FILEs.
+ * This is perfect for work that comes after exec().
+ * Is it really safe for inline use? Experimentally,
+ * things seem to work. */
+ int rcode = setup_redirects(command, squirrel);
+ if (rcode == 0) {
+ char **new_env = expand_assignments(command->argv, command->assignment_cnt);
+ *new_env_p = new_env;
+ dump_cmd_in_x_mode(new_env);
+ dump_cmd_in_x_mode(argv_expanded);
+ if (old_vars_p)
+ *old_vars_p = set_vars_and_save_old(new_env);
+ }
+ return rcode;
+}
static NOINLINE int run_pipe(struct pipe *pi)
{
static const char *const null_ptr = NULL;
@@ -4325,7 +4365,6 @@ static NOINLINE int run_pipe(struct pipe *pi)
struct command *command;
char **argv_expanded;
char **argv;
- char *p;
/* it is not always needed, but we aim to smaller code */
int squirrel[] = { -1, -1, -1 };
int rcode;
@@ -4402,19 +4441,45 @@ static NOINLINE int run_pipe(struct pipe *pi)
if (argv[command->assignment_cnt] == NULL) {
/* Assignments, but no command */
/* Ensure redirects take effect (that is, create files).
- * Try "a=t >file": */
+ * Try "a=t >file" */
+#if 0 /* A few cases in testsuite fail with this code. FIXME */
+ rcode = redirect_and_varexp_helper(&new_env, /*old_vars:*/ NULL, command, squirrel, /*argv_expanded:*/ NULL);
+ /* Set shell variables */
+ if (new_env) {
+ argv = new_env;
+ while (*argv) {
+ set_local_var(*argv, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
+ /* Do we need to flag set_local_var() errors?
+ * "assignment to readonly var" and "putenv error"
+ */
+ argv++;
+ }
+ }
+ /* Redirect error sets $? to 1. Otherwise,
+ * if evaluating assignment value set $?, retain it.
+ * Try "false; q=`exit 2`; echo $?" - should print 2: */
+ if (rcode == 0)
+ rcode = G.last_exitcode;
+ /* Exit, _skipping_ variable restoring code: */
+ goto clean_up_and_ret0;
+
+#else /* Older, bigger, but more correct code */
+
rcode = setup_redirects(command, squirrel);
restore_redirects(squirrel);
/* Set shell variables */
if (G_x_mode)
bb_putchar_stderr('+');
while (*argv) {
- p = expand_string_to_string(*argv);
+ char *p = expand_string_to_string(*argv);
if (G_x_mode)
fprintf(stderr, " %s", p);
debug_printf_exec("set shell var:'%s'->'%s'\n",
*argv, p);
set_local_var(p, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
+ /* Do we need to flag set_local_var() errors?
+ * "assignment to readonly var" and "putenv error"
+ */
argv++;
}
if (G_x_mode)
@@ -4424,13 +4489,11 @@ static NOINLINE int run_pipe(struct pipe *pi)
* Try "false; q=`exit 2`; echo $?" - should print 2: */
if (rcode == 0)
rcode = G.last_exitcode;
- /* Do we need to flag set_local_var() errors?
- * "assignment to readonly var" and "putenv error"
- */
IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
debug_leave();
debug_printf_exec("run_pipe: return %d\n", rcode);
return rcode;
+#endif
}
/* Expand the rest into (possibly) many strings each */
@@ -4471,16 +4534,8 @@ static NOINLINE int run_pipe(struct pipe *pi)
goto clean_up_and_ret1;
}
}
- /* setup_redirects acts on file descriptors, not FILEs.
- * This is perfect for work that comes after exec().
- * Is it really safe for inline use? Experimentally,
- * things seem to work. */
- rcode = setup_redirects(command, squirrel);
+ rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, squirrel, argv_expanded);
if (rcode == 0) {
- new_env = expand_assignments(argv, command->assignment_cnt);
- dump_cmd_in_x_mode(new_env);
- dump_cmd_in_x_mode(argv_expanded);
- old_vars = set_vars_and_save_old(new_env);
if (!funcp) {
debug_printf_exec(": builtin '%s' '%s'...\n",
x->b_cmd, argv_expanded[1]);
@@ -4504,9 +4559,10 @@ static NOINLINE int run_pipe(struct pipe *pi)
#endif
}
clean_up_and_ret:
- restore_redirects(squirrel);
unset_vars(new_env);
add_vars(old_vars);
+/* clean_up_and_ret0: */
+ restore_redirects(squirrel);
clean_up_and_ret1:
free(argv_expanded);
IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
@@ -4518,12 +4574,8 @@ static NOINLINE int run_pipe(struct pipe *pi)
if (ENABLE_FEATURE_SH_STANDALONE) {
int n = find_applet_by_name(argv_expanded[0]);
if (n >= 0 && APPLET_IS_NOFORK(n)) {
- rcode = setup_redirects(command, squirrel);
+ rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, squirrel, argv_expanded);
if (rcode == 0) {
- new_env = expand_assignments(argv, command->assignment_cnt);
- dump_cmd_in_x_mode(new_env);
- dump_cmd_in_x_mode(argv_expanded);
- old_vars = set_vars_and_save_old(new_env);
debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
argv_expanded[0], argv_expanded[1]);
rcode = run_nofork_applet(n, argv_expanded);
diff --git a/shell/hush_test/hush-vars/var_serial.right b/shell/hush_test/hush-vars/var_serial.right
new file mode 100644
index 0000000..42aa330
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_serial.right
@@ -0,0 +1,5 @@
+Assignments only: c=a
+Assignments and a command: c=a
+Assignments and a builtin: c=a
+Assignments and a function: c=a
+Done
diff --git a/shell/hush_test/hush-vars/var_serial.tests b/shell/hush_test/hush-vars/var_serial.tests
new file mode 100755
index 0000000..6b4a4cd
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_serial.tests
@@ -0,0 +1,22 @@
+a=a
+
+b=b
+c=c
+# Second assignment depends on the first:
+b=$a c=$b
+echo Assignments only: c=$c
+
+b=b
+c=c
+b=$a c=$b "$THIS_SH" -c 'echo Assignments and a command: c=$c'
+
+b=b
+c=c
+b=$a c=$b eval 'echo Assignments and a builtin: c=$c'
+
+b=b
+c=c
+f() { echo Assignments and a function: c=$c; }
+b=$a c=$b f
+
+echo Done
--
1.7.1
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