[PATCH v12 13/24] cli: hush_modern: Enable variables expansion for modern hush

Francis Laniel
2023-12-08T22:33:17Z

Enables variables expansion for modern hush, both for local and environment
variables.
So the following commands:
foo=bar
echo $foo
setenv bar foo
echo $bar
leads to "bar" and "foo" being printed on console output.

Signed-off-by: Francis Laniel <francis.laniel@amarulasolutions.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
common/cli_hush_modern.c | 17 +++++++
common/cli_hush_upstream.c | 91 +++++++++++++++++++++++++++++++++++---
2 files changed, 103 insertions(+), 5 deletions(-)

diff --git a/common/cli_hush_modern.c b/common/cli_hush_modern.c
index 626fed089b..15bb1f0d92 100644
--- a/common/cli_hush_modern.c
+++ b/common/cli_hush_modern.c
@@ -207,6 +207,23 @@ static const char* endofname(const char *name)
return name;
}

+/**
+ * list_size() - returns the number of elements in char ** before NULL.
+ *
+ * Argument must contain NULL to signalize its end.
+ *
+ * @list The list to count the number of element.
+ * @return The number of element in list.
+ */
+static size_t list_size(char **list)
+{
+ size_t size;
+
+ for (size = 0; list[size] != NULL; size++);
+
+ return size;
+}
+
struct in_str;
static int u_boot_cli_readline(struct in_str *i);

diff --git a/common/cli_hush_upstream.c b/common/cli_hush_upstream.c
index 4b6ab20f3b..ff4a57c6e3 100644
--- a/common/cli_hush_upstream.c
+++ b/common/cli_hush_upstream.c
@@ -3485,7 +3485,6 @@ static int o_get_last_ptr(o_string *o, int n)
return ((int)(uintptr_t)list[n-1]) + string_start;
}

-#ifndef __U_BOOT__
/*
* Globbing routines.
*
@@ -3740,8 +3739,10 @@ static int glob_needed(const char *s)
*/
static int perform_glob(o_string *o, int n)
{
+#ifndef __U_BOOT__
glob_t globdata;
int gr;
+#endif /* __U_BOOT__ */
char *pattern;

debug_printf_glob("start perform_glob: n:%d o->data:%p\n", n, o->data);
@@ -3750,13 +3751,16 @@ static int perform_glob(o_string *o, int n)
pattern = o->data + o_get_last_ptr(o, n);
debug_printf_glob("glob pattern '%s'\n", pattern);
if (!glob_needed(pattern)) {
+#ifndef __U_BOOT__
literal:
+#endif /* __U_BOOT__ */
/* unbackslash last string in o in place, fix length */
o->length = unbackslash(pattern) - o->data;
debug_printf_glob("glob pattern '%s' is literal\n", pattern);
return o_save_ptr_helper(o, n);
}

+#ifndef __U_BOOT__
memset(&globdata, 0, sizeof(globdata));
/* Can't use GLOB_NOCHECK: it does not unescape the string.
* If we glob "*.\*" and don't find anything, we need
@@ -3792,16 +3796,22 @@ static int perform_glob(o_string *o, int n)
if (DEBUG_GLOB)
debug_print_list("perform_glob returning", o, n);
return n;
+#else /* __U_BOOT__ */
+ /*
+ * NOTE We only use perform glob to call unbackslash to remove backslash
+ * from string once expanded.
+ * So, it seems OK to return this if no previous return was done.
+ */
+ return o_save_ptr_helper(o, n);
+#endif /* __U_BOOT__ */
}

-#endif /* !__U_BOOT__ */
#endif /* !HUSH_BRACE_EXPANSION */

/* If o->o_expflags & EXP_FLAG_GLOB, glob the string so far remembered.
* Otherwise, just finish current list[] and start new */
static int o_save_ptr(o_string *o, int n)
{
-#ifndef __U_BOOT__
if (o->o_expflags & EXP_FLAG_GLOB) {
/* If o->has_empty_slot, list[n] was already globbed
* (if it was requested back then when it was filled)
@@ -3809,7 +3819,6 @@ static int o_save_ptr(o_string *o, int n)
if (!o->has_empty_slot)
return perform_glob(o, n); /* o_save_ptr_helper is inside */
}
-#endif /* !__U_BOOT__ */
return o_save_ptr_helper(o, n);
}

@@ -5455,7 +5464,20 @@ static int parse_dollar(o_string *as_string,
nommu_addchr(as_string, ch);
if (ch == '}')
break;
+#ifndef __U_BOOT__
if (!isalnum(ch) && ch != '_') {
+#else /* __U_BOOT__ */
+ /*
+ * In several places in U-Boot, we use variable like
+ * foo# (e.g. serial#), particularly in env.
+ * So, we need to authorize # to appear inside
+ * variable name and then expand this variable.
+ * NOTE Having # in variable name is not permitted in
+ * upstream hush but expansion will be done (even though
+ * the result will be empty).
+ */
+ if (!isalnum(ch) && ch != '_' && ch != '#') {
+#endif /* __U_BOOT__ */
unsigned end_ch;
#ifndef __U_BOOT__
unsigned char last_ch;
@@ -7030,7 +7052,20 @@ static NOINLINE int expand_one_var(o_string *output, int n,
}
#endif /* !__U_BOOT__ */
default:
+#ifndef __U_BOOT__
val = get_local_var_value(var);
+#else /* __U_BOOT__ */
+ /*
+ * Environment variable set with setenv* have to be
+ * expanded.
+ * So, we first search if the variable exists in
+ * environment, if this is not the case, we default to
+ * local value.
+ */
+ val = env_get(var);
+ if (!val)
+ val = get_local_var_value(var);
+#endif /* __U_BOOT__ */
}
}

@@ -7375,7 +7410,11 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
case '*':
case '@': {
int i;
+#ifndef __U_BOOT__
if (!G.global_argv[1])
+#else /* __U_BOOT__ */
+ if (!G.global_argv || !G.global_argv[1])
+#endif /* __U_BOOT__ */
break;
i = 1;
cant_be_null |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
@@ -9976,7 +10015,30 @@ static NOINLINE int run_pipe(struct pipe *pi)
#endif /* !__U_BOOT__ */
command = &pi->cmds[cmd_no];
cmd_no++;
- if (command->argv) {
+
+#ifdef __U_BOOT__
+ /* Replace argv and argc by expanded if it exists. */
+ if (argv_expanded) {
+ /*
+ * We need to save a pointer to argv, we will restore it
+ * later, so it will be freed when pipe is freed.
+ */
+ argv = command->argv;
+
+ /*
+ * After expansion, there can be more or less argument, so we need to
+ * update argc, for example:
+ * - More arguments:
+ * foo='bar quuz'
+ * echo $foo
+ * - Less arguments:
+ * echo $foo (if foo was never set)
+ */
+ command->argc = list_size(argv_expanded);
+ command->argv = argv_expanded;
+ }
+#endif /* __U_BOOT__ */
+ if (command->argv) {
debug_printf_exec(": pipe member '%s' '%s'...\n",
command->argv[0], command->argv[1]);
} else {
@@ -10091,6 +10153,25 @@ static NOINLINE int run_pipe(struct pipe *pi)
rcode = cmd_process(G.do_repeat ? CMD_FLAG_REPEAT : 0,
command->argc, command->argv,
&(G.flag_repeat), NULL);
+
+ if (argv_expanded) {
+ /*
+ * expand_strvec_to_strvec() allocates memory to expand
+ * argv, we need to free it.
+ */
+ free(argv_expanded);
+
+ /*
+ * We also restore command->argv to its original value
+ * so no memory leak happens.
+ */
+ command->argv = argv;
+
+ /*
+ * NOTE argc exists only in U-Boot, so argv freeing does
+ * not rely on it as this code exists in BusyBox.
+ */
+ }
#endif /* __U_BOOT__ */
}

--
2.34.1