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hush: support "! cmd | cmd" negation

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function                                             old     new   delta
done_word                                            749     791     +42
run_list                                            1821    1859     +38
checkjobs                                            334     351     +17
done_pipe                                             61      74     +13
static.reserved_list                                 132     144     +12
initialize_context                                    53      45      -8
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/1 up/down: 122/-8)            Total: 114 bytes
This commit is contained in:
Denis Vlasenko 2008-06-14 11:00:17 +00:00
parent 6108dc4df6
commit a84420062a
6 changed files with 172 additions and 90 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

203
shell/hush.c
View File

@ -20,10 +20,10 @@
* rewrites.
*
* Other credits:
* o_addchr() derived from similar w_addchar function in glibc-2.2
* o_addchr() derived from similar w_addchar function in glibc-2.2.
* setup_redirect(), redirect_opt_num(), and big chunks of main()
* and many builtins derived from contributions by Erik Andersen
* miscellaneous bugfixes from Matt Kraai
* miscellaneous bugfixes from Matt Kraai.
*
* There are two big (and related) architecture differences between
* this parser and the lash parser. One is that this version is
@ -38,7 +38,6 @@
*
* Bash grammar not implemented: (how many of these were in original sh?)
* $_
* ! negation operator for pipes
* &> and >& redirection of stdout+stderr
* Brace Expansion
* Tilde Expansion
@ -54,24 +53,16 @@
* reserved word execution woefully incomplete and buggy
* to-do:
* port selected bugfixes from post-0.49 busybox lash - done?
* finish implementing reserved words: for, while, until, do, done
* change { and } from special chars to reserved words
* builtins: break, continue, eval, return, set, trap, ulimit
* test magic exec
* handle children going into background
* clean up recognition of null pipes
* check setting of global_argc and global_argv
* control-C handling, probably with longjmp
* follow IFS rules more precisely, including update semantics
* figure out what to do with backslash-newline
* explain why we use signal instead of sigaction
* propagate syntax errors, die on resource errors?
* continuation lines, both explicit and implicit - done?
* memory leak finding and plugging - done?
* more testing, especially quoting rules and redirection
* document how quoting rules not precisely followed for variable assignments
* maybe change charmap[] to use 2-bit entries
* (eventually) remove all the printf's
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
@ -244,26 +235,6 @@ typedef enum {
RES_XXXX = 12,
RES_SNTX = 13
} reserved_style;
enum {
FLAG_END = (1 << RES_NONE ),
#if ENABLE_HUSH_IF
FLAG_IF = (1 << RES_IF ),
FLAG_THEN = (1 << RES_THEN ),
FLAG_ELIF = (1 << RES_ELIF ),
FLAG_ELSE = (1 << RES_ELSE ),
FLAG_FI = (1 << RES_FI ),
#endif
#if ENABLE_HUSH_LOOPS
FLAG_FOR = (1 << RES_FOR ),
FLAG_WHILE = (1 << RES_WHILE),
FLAG_UNTIL = (1 << RES_UNTIL),
FLAG_DO = (1 << RES_DO ),
FLAG_DONE = (1 << RES_DONE ),
FLAG_IN = (1 << RES_IN ),
#endif
FLAG_START = (1 << RES_XXXX ),
};
/* This holds pointers to the various results of parsing */
struct p_context {
struct child_prog *child;
@ -271,7 +242,8 @@ struct p_context {
struct pipe *pipe;
struct redir_struct *pending_redirect;
smallint res_w;
smallint parse_type; /* bitmask of PARSEFLAG_xxx, defines type of parser : ";$" common or special symbol */
smallint parse_type; /* bitmask of PARSEFLAG_xxx, defines type of parser: ";$" common or special symbol */
smallint ctx_inverted; /* "! cmd | cmd" */
int old_flag; /* bitmask of FLAG_xxx, for figuring out valid reserved words */
struct p_context *stack;
/* How about quoting status? */
@ -313,6 +285,7 @@ struct pipe {
char *cmdbuf; /* buffer various argv's point into */
struct child_prog *progs; /* array of commands in pipe */
int job_context; /* bitmask defining current context */
smallint pi_inverted; /* "! cmd | cmd" */
smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
smallint res_word; /* needed for if, for, while, until... */
};
@ -524,7 +497,7 @@ static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struc
static void initialize_context(struct p_context *ctx);
static int done_word(o_string *dest, struct p_context *ctx);
static int done_command(struct p_context *ctx);
static int done_pipe(struct p_context *ctx, pipe_style type);
static void done_pipe(struct p_context *ctx, pipe_style type);
/* primary string parsing: */
static int redirect_dup_num(struct in_str *input);
static int redirect_opt_num(o_string *o);
@ -1648,9 +1621,6 @@ static void pseudo_exec_argv(char **ptrs2free, char **argv)
*/
static void pseudo_exec(char **ptrs2free, struct child_prog *child)
{
// FIXME: buggy wrt NOMMU! Must not modify any global data
// until it does exec/_exit, but currently it does
// (puts malloc'ed stuff into environment)
if (child->argv)
pseudo_exec_argv(ptrs2free, child->argv);
@ -1691,8 +1661,10 @@ static const char *get_cmdtext(struct pipe *pi)
if (pi->cmdtext)
return pi->cmdtext;
argv = pi->progs[0].argv;
if (!argv || !argv[0])
return (pi->cmdtext = xzalloc(1));
if (!argv || !argv[0]) {
pi->cmdtext = xzalloc(1);
return pi->cmdtext;
}
len = 0;
do len += strlen(*argv) + 1; while (*++argv);
@ -1833,9 +1805,12 @@ static int checkjobs(struct pipe* fg_pipe)
if (dead) {
fg_pipe->progs[i].pid = 0;
fg_pipe->running_progs--;
if (i == fg_pipe->num_progs - 1)
if (i == fg_pipe->num_progs - 1) {
/* last process gives overall exitstatus */
rcode = WEXITSTATUS(status);
if (fg_pipe->pi_inverted)
rcode = !rcode;
}
} else {
fg_pipe->progs[i].is_stopped = 1;
fg_pipe->stopped_progs++;
@ -1966,6 +1941,8 @@ static int run_pipe(struct pipe *pi)
rcode = run_list(child->group) & 0xff;
restore_redirects(squirrel);
debug_printf_exec("run_pipe return %d\n", rcode);
if (pi->pi_inverted)
rcode = !rcode;
return rcode;
}
@ -2007,6 +1984,8 @@ static int run_pipe(struct pipe *pi)
free(argv_expanded);
restore_redirects(squirrel);
debug_printf_exec("run_pipe return %d\n", rcode);
if (pi->pi_inverted)
rcode = !rcode;
return rcode;
}
}
@ -2023,6 +2002,8 @@ static int run_pipe(struct pipe *pi)
free(argv_expanded);
restore_redirects(squirrel);
debug_printf_exec("run_pipe return %d\n", rcode);
if (pi->pi_inverted)
rcode = !rcode;
return rcode;
}
}
@ -2985,7 +2966,8 @@ static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
/* Check for a '2>&1' type redirect */
redir->dup = redirect_dup_num(input);
if (redir->dup == -2) return 1; /* syntax error */
if (redir->dup == -2)
return 1; /* syntax error */
if (redir->dup != -1) {
/* Erik had a check here that the file descriptor in question
* is legit; I postpone that to "run time"
@ -3005,10 +2987,7 @@ static struct pipe *new_pipe(void)
{
struct pipe *pi;
pi = xzalloc(sizeof(struct pipe));
/*pi->num_progs = 0;*/
/*pi->progs = NULL;*/
/*pi->next = NULL;*/
/*pi->followup = 0; invalid */
/*pi->followup = 0; - deliberately invalid value */
if (RES_NONE)
pi->res_word = RES_NONE;
return pi;
@ -3016,29 +2995,50 @@ static struct pipe *new_pipe(void)
static void initialize_context(struct p_context *ctx)
{
ctx->child = NULL;
smallint sv = ctx->parse_type;
memset(ctx, 0, sizeof(*ctx));
ctx->parse_type = sv;
ctx->pipe = ctx->list_head = new_pipe();
ctx->pending_redirect = NULL;
ctx->res_w = RES_NONE;
//only ctx->parse_type is not touched... is this intentional?
ctx->old_flag = 0;
ctx->stack = NULL;
done_command(ctx); /* creates the memory for working child */
/* Create the memory for child, roughly:
* ctx->pipe->progs = new struct child_prog;
* ctx->pipe->progs[0].family = ctx->pipe;
* ctx->child = &ctx->pipe->progs[0];
*/
done_command(ctx);
}
/* normal return is 0
* if a reserved word is found, and processed, return 1
* should handle if, then, elif, else, fi, for, while, until, do, done.
/* If a reserved word is found and processed, parse context is modified
* and 1 is returned.
* Handles if, then, elif, else, fi, for, while, until, do, done.
* case, function, and select are obnoxious, save those for later.
*/
#if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS
static int reserved_word(o_string *dest, struct p_context *ctx)
static int reserved_word(const o_string *word, struct p_context *ctx)
{
struct reserved_combo {
char literal[7];
unsigned char code;
unsigned char res;
int flag;
};
enum {
FLAG_END = (1 << RES_NONE ),
#if ENABLE_HUSH_IF
FLAG_IF = (1 << RES_IF ),
FLAG_THEN = (1 << RES_THEN ),
FLAG_ELIF = (1 << RES_ELIF ),
FLAG_ELSE = (1 << RES_ELSE ),
FLAG_FI = (1 << RES_FI ),
#endif
#if ENABLE_HUSH_LOOPS
FLAG_FOR = (1 << RES_FOR ),
FLAG_WHILE = (1 << RES_WHILE),
FLAG_UNTIL = (1 << RES_UNTIL),
FLAG_DO = (1 << RES_DO ),
FLAG_DONE = (1 << RES_DONE ),
FLAG_IN = (1 << RES_IN ),
#endif
FLAG_START = (1 << RES_XXXX ),
};
/* Mostly a list of accepted follow-up reserved words.
* FLAG_END means we are done with the sequence, and are ready
* to turn the compound list into a command.
@ -3046,6 +3046,7 @@ static int reserved_word(o_string *dest, struct p_context *ctx)
*/
static const struct reserved_combo reserved_list[] = {
#if ENABLE_HUSH_IF
{ "!", RES_NONE, 0 },
{ "if", RES_IF, FLAG_THEN | FLAG_START },
{ "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
{ "elif", RES_ELIF, FLAG_THEN },
@ -3053,9 +3054,9 @@ static int reserved_word(o_string *dest, struct p_context *ctx)
{ "fi", RES_FI, FLAG_END },
#endif
#if ENABLE_HUSH_LOOPS
{ "for", RES_FOR, FLAG_IN | FLAG_START },
{ "while", RES_WHILE, FLAG_DO | FLAG_START },
{ "until", RES_UNTIL, FLAG_DO | FLAG_START },
{ "for", RES_FOR, FLAG_IN | FLAG_START },
{ "while", RES_WHILE, FLAG_DO | FLAG_START },
{ "until", RES_UNTIL, FLAG_DO | FLAG_START },
{ "in", RES_IN, FLAG_DO },
{ "do", RES_DO, FLAG_DONE },
{ "done", RES_DONE, FLAG_END }
@ -3065,9 +3066,23 @@ static int reserved_word(o_string *dest, struct p_context *ctx)
const struct reserved_combo *r;
for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
if (strcmp(dest->data, r->literal) != 0)
if (strcmp(word->data, r->literal) != 0)
continue;
debug_printf("found reserved word %s, code %d\n", r->literal, r->code);
debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
if (r->flag == 0) { /* '!' */
if (ctx->res_w == RES_IN) {
/* 'for a in ! a b c; ...' - ! isn't a keyword here */
break;
}
if (ctx->res_w == RES_FOR /* example: 'for ! a' */
|| ctx->ctx_inverted /* bash doesn't accept '! ! true' */
) {
syntax(NULL);
ctx->res_w = RES_SNTX;
}
ctx->ctx_inverted = 1;
return 1;
}
if (r->flag & FLAG_START) {
struct p_context *new;
debug_printf("push stack\n");
@ -3075,7 +3090,6 @@ static int reserved_word(o_string *dest, struct p_context *ctx)
if (ctx->res_w == RES_IN || ctx->res_w == RES_FOR) {
syntax("malformed for"); /* example: 'for if' */
ctx->res_w = RES_SNTX;
o_reset(dest);
return 1;
}
#endif
@ -3083,13 +3097,12 @@ static int reserved_word(o_string *dest, struct p_context *ctx)
*new = *ctx; /* physical copy */
initialize_context(ctx);
ctx->stack = new;
} else if (ctx->res_w == RES_NONE || !(ctx->old_flag & (1 << r->code))) {
} else if (ctx->res_w == RES_NONE || !(ctx->old_flag & (1 << r->res))) {
syntax(NULL);
ctx->res_w = RES_SNTX;
o_reset(dest);
return 1;
}
ctx->res_w = r->code;
ctx->res_w = r->res;
ctx->old_flag = r->flag;
if (ctx->old_flag & FLAG_END) {
struct p_context *old;
@ -3101,52 +3114,55 @@ static int reserved_word(o_string *dest, struct p_context *ctx)
*ctx = *old; /* physical copy */
free(old);
}
o_reset(dest);
return 1;
}
return 0;
}
#else
#define reserved_word(dest, ctx) ((int)0)
#define reserved_word(word, ctx) ((int)0)
#endif
/* Normal return is 0.
/* Word is complete, look at it and update parsing context.
* Normal return is 0.
* Syntax or xglob errors return 1. */
static int done_word(o_string *dest, struct p_context *ctx)
static int done_word(o_string *word, struct p_context *ctx)
{
struct child_prog *child = ctx->child;
char ***glob_target;
int gr;
debug_printf_parse("done_word entered: '%s' %p\n", dest->data, child);
if (dest->length == 0 && !dest->nonnull) {
debug_printf_parse("done_word entered: '%s' %p\n", word->data, child);
if (word->length == 0 && !word->nonnull) {
debug_printf_parse("done_word return 0: true null, ignored\n");
return 0;
}
if (ctx->pending_redirect) {
glob_target = &ctx->pending_redirect->glob_word;
} else {
if (child->group) {
if (child->group) { /* TODO: example how to trigger? */
syntax(NULL);
debug_printf_parse("done_word return 1: syntax error, groups and arglists don't mix\n");
return 1;
}
if (!child->argv && (ctx->parse_type & PARSEFLAG_SEMICOLON)) {
debug_printf_parse(": checking '%s' for reserved-ness\n", dest->data);
if (reserved_word(dest, ctx)) {
debug_printf_parse(": checking '%s' for reserved-ness\n", word->data);
if (reserved_word(word, ctx)) {
o_reset(word);
debug_printf_parse("done_word return %d\n", (ctx->res_w == RES_SNTX));
return (ctx->res_w == RES_SNTX);
}
}
glob_target = &child->argv;
}
gr = xglob(dest, glob_target);
//BUG! globbing should be done after variable expansion!
//See glob_and_vars testcase
gr = xglob(word, glob_target);
if (gr != 0) {
debug_printf_parse("done_word return 1: xglob returned %d\n", gr);
return 1;
}
o_reset(dest);
o_reset(word);
if (ctx->pending_redirect) {
/* NB: don't free_strings(ctx->pending_redirect->glob_word) here */
if (ctx->pending_redirect->glob_word
@ -3162,8 +3178,11 @@ static int done_word(o_string *dest, struct p_context *ctx)
ctx->pending_redirect = NULL;
}
#if ENABLE_HUSH_LOOPS
if (ctx->res_w == RES_FOR) {
done_word(dest, ctx);
if (ctx->res_w == RES_FOR) { /* comment? */
//TESTING
//looks like (word->length == 0 && !word->nonnull) is true here, always
//(due to o_reset). done_word would return at once. Why then?
// done_word(word, ctx);
done_pipe(ctx, PIPE_SEQ);
}
#endif
@ -3200,10 +3219,6 @@ static int done_command(struct p_context *ctx)
child = &pi->progs[pi->num_progs];
memset(child, 0, sizeof(*child));
/*child->redirects = NULL;*/
/*child->argv = NULL;*/
/*child->is_stopped = 0;*/
/*child->group = NULL;*/
child->family = pi;
ctx->child = child;
@ -3212,7 +3227,7 @@ static int done_command(struct p_context *ctx)
return pi->num_progs; /* used only for 0/nonzero check */
}
static int done_pipe(struct p_context *ctx, pipe_style type)
static void done_pipe(struct p_context *ctx, pipe_style type)
{
struct pipe *new_p;
int not_null;
@ -3221,6 +3236,8 @@ static int done_pipe(struct p_context *ctx, pipe_style type)
not_null = done_command(ctx); /* implicit closure of previous command */
ctx->pipe->followup = type;
ctx->pipe->res_word = ctx->res_w;
ctx->pipe->pi_inverted = ctx->ctx_inverted;
ctx->ctx_inverted = 0;
/* Without this check, even just <enter> on command line generates
* tree of three NOPs (!). Which is harmless but annoying.
* IOW: it is safe to do it unconditionally. */
@ -3228,11 +3245,15 @@ static int done_pipe(struct p_context *ctx, pipe_style type)
new_p = new_pipe();
ctx->pipe->next = new_p;
ctx->pipe = new_p;
ctx->child = NULL;
done_command(ctx); /* set up new pipe to accept commands */
ctx->child = NULL; /* needed! */
/* Create the memory for child, roughly:
* ctx->pipe->progs = new struct child_prog;
* ctx->pipe->progs[0].family = ctx->pipe;
* ctx->child = &ctx->pipe->progs[0];
*/
done_command(ctx);
}
debug_printf_parse("done_pipe return 0\n");
return 0;
debug_printf_parse("done_pipe return\n");
}
/* peek ahead in the in_str to find out if we have a "&n" construct,
@ -3826,7 +3847,8 @@ static int parse_stream(o_string *dest, struct p_context *ctx,
break;
case ')':
case '}':
syntax("unexpected }"); /* Proper use of this character is caught by end_trigger */
/* proper use of this character is caught by end_trigger */
syntax("unexpected } or )");
debug_printf_parse("parse_stream return 1: unexpected '}'\n");
return 1;
default:
@ -3880,10 +3902,14 @@ static void update_charmap(void)
* from builtin_source() and builtin_eval() */
static int parse_and_run_stream(struct in_str *inp, int parse_flag)
{
//TODO: PARSEFLAG_SEMICOLON bit is always set in parse_flag. fishy
//TODO: PARSEFLAG_REPARSING bit is never set (grep for it). wow
struct p_context ctx;
o_string temp = NULL_O_STRING;
int rcode;
do {
// It always has PARSEFLAG_SEMICOLON, can we remove all checks for this bit?
// After that, the whole parse_type fiels is not needed.
ctx.parse_type = parse_flag;
initialize_context(&ctx);
update_charmap();
@ -3922,6 +3948,7 @@ static int parse_and_run_stream(struct in_str *inp, int parse_flag)
static int parse_and_run_string(const char *s, int parse_flag)
{
//TODO: PARSEFLAG_SEMICOLON bit is always set in parse_flag. fishy
struct in_str input;
setup_string_in_str(&input, s);
return parse_and_run_stream(&input, parse_flag);

2
shell/hush_test/hush-misc/syntax_err_negate.right Normal file
View File

@ -0,0 +1,2 @@
bash 3.2 fails this
hush: syntax error

2
shell/hush_test/hush-misc/syntax_err_negate.tests Executable file
View File

@ -0,0 +1,2 @@
echo bash 3.2 fails this
! ! true

35
shell/hush_test/hush-parsing/negate.right Normal file
View File

@ -0,0 +1,35 @@
! printing !
0
1
1
0
0
0
!
a
b
c
! 1
a 1
b 1
c 1
! 1
a 1
b 1
c 1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1

16
shell/hush_test/hush-parsing/negate.tests Executable file
View File

@ -0,0 +1,16 @@
echo ! printing !
! false
echo $?
! true
echo $?
if ! false; then false; echo $?; fi
echo $?
if ! false; then ! false; echo $?; fi
echo $?
for a in ! a b c; do echo $a; done
for a in ! a b c; do ! echo -n "$a "; echo $?; done
for a in ! a b c; do ! /bin/echo -n "$a "; echo $?; done
for a in ! a b c; do ! echo -n "$a " | false; echo $?; done
for a in ! a b c; do ! echo -n "$a " | true; echo $?; done
for a in ! a b c; do ! { echo -n "$a " | false; }; echo $?; done
for a in ! a b c; do ! { echo -n "$a " | true; }; echo $?; done

4
shell/hush_test/run-all
View File

@ -1,8 +1,8 @@
#!/bin/sh
test -x hush || {
echo "No ./hush?! Perhaps you want to run 'ln -s ../../busybox hush'"
exit
echo "No ./hush - creating a link to ../../busybox"
ln -s ../../busybox hush
}
PATH="$PWD:$PATH" # for hush and recho/zecho/printenv