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hush: make builtins work in pipes (eval ... | ...) on NOMMU

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-06-06 20:59:55 +02:00
parent 62152da892
commit d6b05eb9c2
4 changed files with 185 additions and 93 deletions
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2
shell/ash.c
View File

@ -12233,7 +12233,7 @@ helpcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
unsigned col;
unsigned i;
out1fmt("\n"
out1fmt(
"Built-in commands:\n"
"------------------\n");
for (col = 0, i = 0; i < ARRAY_SIZE(builtintab); i++) {

272
shell/hush.c
View File

@ -50,7 +50,7 @@
*
* TODOs:
* grep for "TODO" and fix (some of them are easy)
* builtins: ulimit, local
* builtins: ulimit
* follow IFS rules more precisely, including update semantics
* export builtin should be special, its arguments are assignments
* and therefore expansion of them should be "one-word" expansion:
@ -593,56 +593,58 @@ struct built_in_command {
#endif
};
/* For now, echo and test are unconditionally enabled.
* Maybe make it configurable? */
static const struct built_in_command bltins[] = {
BLTIN("." , builtin_source , "Run commands in a file"),
BLTIN(":" , builtin_true , "No-op"),
BLTIN("[" , builtin_test , "Test condition"),
static const struct built_in_command bltins1[] = {
BLTIN("." , builtin_source , "Run commands in a file"),
BLTIN(":" , builtin_true , NULL),
#if ENABLE_HUSH_JOB
BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
#endif
#if ENABLE_HUSH_LOOPS
BLTIN("break" , builtin_break , "Exit from a loop"),
BLTIN("break" , builtin_break , "Exit from a loop"),
#endif
BLTIN("cd" , builtin_cd , "Change directory"),
BLTIN("cd" , builtin_cd , "Change directory"),
#if ENABLE_HUSH_LOOPS
BLTIN("continue", builtin_continue, "Start new loop iteration"),
BLTIN("continue" , builtin_continue, "Start new loop iteration"),
#endif
BLTIN("echo" , builtin_echo , "Write to stdout"),
BLTIN("eval" , builtin_eval , "Construct and run shell command"),
BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
BLTIN("exit" , builtin_exit , "Exit"),
BLTIN("export" , builtin_export , "Set environment variable"),
BLTIN("eval" , builtin_eval , "Construct and run shell command"),
BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
BLTIN("exit" , builtin_exit , "Exit"),
BLTIN("export" , builtin_export , "Set environment variables"),
#if ENABLE_HUSH_JOB
BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
#endif
#if ENABLE_HUSH_HELP
BLTIN("help" , builtin_help , "List shell built-in commands"),
BLTIN("help" , builtin_help , NULL),
#endif
#if ENABLE_HUSH_JOB
BLTIN("jobs" , builtin_jobs , "List active jobs"),
BLTIN("jobs" , builtin_jobs , "List jobs"),
#endif
#if ENABLE_HUSH_LOCAL
BLTIN("local" , builtin_local , "Set local variable"),
BLTIN("local" , builtin_local , "Set local variables"),
#endif
#if HUSH_DEBUG
BLTIN("memleak" , builtin_memleak , "Debug tool"),
BLTIN("memleak" , builtin_memleak , NULL),
#endif
BLTIN("pwd" , builtin_pwd , "Print current directory"),
BLTIN("read" , builtin_read , "Input environment variable"),
BLTIN("read" , builtin_read , "Input into variable"),
#if ENABLE_HUSH_FUNCTIONS
BLTIN("return" , builtin_return , "Return from a function"),
BLTIN("return" , builtin_return , "Return from a function"),
#endif
BLTIN("set" , builtin_set , "Set/unset shell local variables"),
BLTIN("shift" , builtin_shift , "Shift positional parameters"),
BLTIN("test" , builtin_test , "Test condition"),
BLTIN("trap" , builtin_trap , "Trap signals"),
BLTIN("type" , builtin_type , "Write a description of command type"),
// BLTIN("ulimit" , builtin_ulimit , "Control resource limits"),
BLTIN("umask" , builtin_umask , "Set file creation mask"),
BLTIN("unset" , builtin_unset , "Unset environment variable"),
BLTIN("wait" , builtin_wait , "Wait for process"),
BLTIN("set" , builtin_set , "Set/unset positional parameters"),
BLTIN("shift" , builtin_shift , "Shift positional parameters"),
BLTIN("trap" , builtin_trap , "Trap signals"),
BLTIN("type" , builtin_type , "Write a description of command type"),
// BLTIN("ulimit" , builtin_ulimit , "Control resource limits"),
BLTIN("umask" , builtin_umask , "Set file creation mask"),
BLTIN("unset" , builtin_unset , "Unset variables"),
BLTIN("wait" , builtin_wait , "Wait for process"),
};
/* For now, echo and test are unconditionally enabled.
* Maybe make it configurable? */
static const struct built_in_command bltins2[] = {
BLTIN("[" , builtin_test , NULL),
BLTIN("echo" , builtin_echo , NULL),
BLTIN("pwd" , builtin_pwd , NULL),
BLTIN("test" , builtin_test , NULL),
};
@ -1231,15 +1233,17 @@ static int check_and_run_traps(int sig)
}
static const char *set_cwd(void)
static const char *get_cwd(int force)
{
/* xrealloc_getcwd_or_warn(arg) calls free(arg),
* we must not try to free(bb_msg_unknown) */
if (G.cwd == bb_msg_unknown)
G.cwd = NULL;
G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
if (!G.cwd)
G.cwd = bb_msg_unknown;
if (force || G.cwd == NULL) {
/* xrealloc_getcwd_or_warn(arg) calls free(arg),
* we must not try to free(bb_msg_unknown) */
if (G.cwd == bb_msg_unknown)
G.cwd = NULL;
G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
if (!G.cwd)
G.cwd = bb_msg_unknown;
}
return G.cwd;
}
@ -1579,7 +1583,7 @@ static const char* setup_prompt_string(int promptmode)
/* Set up the prompt */
if (promptmode == 0) { /* PS1 */
free((char*)G.PS1);
G.PS1 = xasprintf("%s %c ", G.cwd, (geteuid() != 0) ? '$' : '#');
G.PS1 = xasprintf("%s %c ", get_cwd(0), (geteuid() != 0) ? '$' : '#');
prompt_str = G.PS1;
} else
prompt_str = G.PS2;
@ -2511,7 +2515,9 @@ static char **expand_assignments(char **argv, int count)
#if BB_MMU
/* never called */
void re_execute_shell(char ***to_free, const char *s, char *argv0, char **argv);
void re_execute_shell(char ***to_free, const char *s,
char *g_argv0, char **g_argv,
char **builtin_argv) NORETURN;
static void reset_traps_to_defaults(void)
{
@ -2563,10 +2569,14 @@ static void reset_traps_to_defaults(void)
#else /* !BB_MMU */
static void re_execute_shell(char ***to_free, const char *s, char *g_argv0, char **g_argv) NORETURN;
static void re_execute_shell(char ***to_free, const char *s, char *g_argv0, char **g_argv)
static void re_execute_shell(char ***to_free, const char *s,
char *g_argv0, char **g_argv,
char **builtin_argv) NORETURN;
static void re_execute_shell(char ***to_free, const char *s,
char *g_argv0, char **g_argv,
char **builtin_argv)
{
char param_buf[sizeof("-$%x:%x:%x:%x") + sizeof(unsigned) * 4];
char param_buf[sizeof("-$%x:%x:%x:%x:%x") + sizeof(unsigned) * 2];
char *heredoc_argv[4];
struct variable *cur;
#if ENABLE_HUSH_FUNCTIONS
@ -2585,16 +2595,22 @@ static void re_execute_shell(char ***to_free, const char *s, char *g_argv0, char
goto do_exec;
}
sprintf(param_buf, "-$%x:%x:%x" IF_HUSH_LOOPS(":%x")
cnt = 0;
pp = builtin_argv;
if (pp) while (*pp++)
cnt++;
sprintf(param_buf, "-$%x:%x:%x:%x" IF_HUSH_LOOPS(":%x")
, (unsigned) G.root_pid
, (unsigned) G.last_bg_pid
, (unsigned) G.last_exitcode
, cnt
IF_HUSH_LOOPS(, G.depth_of_loop)
);
/* 1:hush 2:-$<pid>:<pid>:<exitcode>:<depth> <vars...> <funcs...>
* 3:-c 4:<cmd> 5:<arg0> <argN...> 6:NULL
*/
cnt = 6;
cnt += 6;
for (cur = G.top_var; cur; cur = cur->next) {
if (!cur->flg_export || cur->flg_read_only)
cnt += 2;
@ -2648,6 +2664,11 @@ static void re_execute_shell(char ***to_free, const char *s, char *g_argv0, char
*/
*pp++ = (char *) "-c";
*pp++ = (char *) s;
if (builtin_argv) {
while (*++builtin_argv)
*pp++ = *builtin_argv;
*pp++ = (char *) "";
}
*pp++ = g_argv0;
while (*g_argv)
*pp++ = *g_argv++;
@ -2735,7 +2756,7 @@ static void setup_heredoc(struct redir_struct *redir)
#else
/* Delegate blocking writes to another process */
xmove_fd(pair.wr, STDOUT_FILENO);
re_execute_shell(&to_free, heredoc, NULL, NULL);
re_execute_shell(&to_free, heredoc, NULL, NULL, NULL);
#endif
}
/* parent */
@ -2958,17 +2979,31 @@ static char *find_in_path(const char *arg)
return ret;
}
static const struct built_in_command* find_builtin(const char *name)
static const struct built_in_command* find_builtin_helper(const char *name,
const struct built_in_command *x,
const struct built_in_command *end)
{
const struct built_in_command *x;
for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
if (strcmp(name, x->cmd) != 0)
while (x != end) {
if (strcmp(name, x->cmd) != 0) {
x++;
continue;
}
debug_printf_exec("found builtin '%s'\n", name);
return x;
}
return NULL;
}
static const struct built_in_command* find_builtin1(const char *name)
{
return find_builtin_helper(name, bltins1, &bltins1[ARRAY_SIZE(bltins1)]);
}
static const struct built_in_command* find_builtin(const char *name)
{
const struct built_in_command *x = find_builtin1(name);
if (x)
return x;
return find_builtin_helper(name, bltins2, &bltins2[ARRAY_SIZE(bltins2)]);
}
#if ENABLE_HUSH_FUNCTIONS
static const struct function *find_function(const char *name)
@ -3084,7 +3119,8 @@ static void exec_function(nommu_save_t *nommu_save,
re_execute_shell(&nommu_save->argv_from_re_execing,
funcp->body_as_string,
G.global_argv[0],
argv + 1);
argv + 1,
NULL);
# endif
}
@ -3148,6 +3184,37 @@ static int run_function(const struct function *funcp, char **argv)
#endif /* ENABLE_HUSH_FUNCTIONS */
# if BB_MMU
#define exec_builtin(nommu_save, x, argv) \
exec_builtin(x, argv)
# else
#define exec_builtin(nommu_save, x, argv) \
exec_builtin(nommu_save, argv)
# endif
static void exec_builtin(nommu_save_t *nommu_save,
const struct built_in_command *x,
char **argv) NORETURN;
static void exec_builtin(nommu_save_t *nommu_save,
const struct built_in_command *x,
char **argv)
{
# if BB_MMU
int rcode = x->function(argv);
fflush(NULL);
_exit(rcode);
# else
/* On NOMMU, we must never block!
* Example: { sleep 99 | read line; } & echo Ok
*/
re_execute_shell(&nommu_save->argv_from_re_execing,
argv[0],
G.global_argv[0],
G.global_argv + 1,
argv);
# endif
}
#if BB_MMU
#define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
@ -3197,27 +3264,22 @@ static void pseudo_exec_argv(nommu_save_t *nommu_save,
goto skip;
#endif
/* On NOMMU, we must never block!
* Example: { sleep 99999 | read line } & echo Ok
* read builtin will block on read syscall, leaving parent blocked
* in vfork. Therefore we can't do this:
*/
#if BB_MMU
/* Check if the command matches any of the builtins.
* Depending on context, this might be redundant. But it's
* easier to waste a few CPU cycles than it is to figure out
* if this is one of those cases.
*/
{
int rcode;
const struct built_in_command *x = find_builtin(argv[0]);
/* On NOMMU, it is more expensive to re-execute shell
* just in order to run echo or test builtin.
* It's better to skip it here and run corresponding
* non-builtin later. */
const struct built_in_command *x;
x = BB_MMU ? find_builtin(argv[0]) : find_builtin1(argv[0]);
if (x) {
rcode = x->function(argv);
fflush(NULL);
_exit(rcode);
exec_builtin(nommu_save, x, argv);
}
}
#endif
#if ENABLE_HUSH_FUNCTIONS
/* Check if the command matches any functions */
{
@ -3292,7 +3354,8 @@ static void pseudo_exec(nommu_save_t *nommu_save,
re_execute_shell(&nommu_save->argv_from_re_execing,
command->group_as_string,
G.global_argv[0],
G.global_argv + 1);
G.global_argv + 1,
NULL);
#endif
}
@ -5030,7 +5093,8 @@ static FILE *generate_stream_from_string(const char *s)
re_execute_shell(&to_free,
s,
G.global_argv[0],
G.global_argv + 1);
G.global_argv + 1,
NULL);
#endif
}
@ -6240,6 +6304,7 @@ int hush_main(int argc, char **argv)
};
int signal_mask_is_inited = 0;
int opt;
unsigned builtin_argc;
char **e;
struct variable *cur_var;
@ -6277,7 +6342,6 @@ int hush_main(int argc, char **argv)
G.global_argc = argc;
G.global_argv = argv;
/* Initialize some more globals to non-zero values */
set_cwd();
cmdedit_update_prompt();
if (setjmp(die_jmp)) {
@ -6297,6 +6361,7 @@ int hush_main(int argc, char **argv)
/* Parse options */
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
builtin_argc = 0;
while (1) {
opt = getopt(argc, argv, "c:xins"
#if !BB_MMU
@ -6310,15 +6375,40 @@ int hush_main(int argc, char **argv)
break;
switch (opt) {
case 'c':
/* Possibilities:
* sh ... -c 'script'
* sh ... -c 'script' ARG0 [ARG1...]
* On NOMMU, if builtin_argc != 0,
* sh ... -c 'builtin' [BARGV...] "" ARG0 [ARG1...]
* "" needs to be replaced with NULL
* and BARGV vector fed to builtin function.
* Note: this form never happens:
* sh ... -c 'builtin' [BARGV...] ""
*/
if (!G.root_pid)
G.root_pid = getpid();
G.global_argv = argv + optind;
if (!argv[optind]) {
/* -c 'script' (no params): prevent empty $0 */
*--G.global_argv = argv[0];
optind--;
} /* else -c 'script' PAR0 PAR1: $0 is PAR0 */
G.global_argc = argc - optind;
if (builtin_argc) {
/* -c 'builtin' [BARGV...] "" ARG0 [ARG1...] */
const struct built_in_command *x;
block_signals(0); /* 0: called 1st time */
x = find_builtin(optarg);
if (x) { /* paranoia */
G.global_argc -= builtin_argc; /* skip [BARGV...] "" */
G.global_argv += builtin_argc;
G.global_argv[-1] = NULL; /* replace "" */
G.last_exitcode = x->function(argv + optind - 1);
}
goto final_return;
}
if (!G.global_argv[0]) {
/* -c 'script' (no params): prevent empty $0 */
G.global_argv--; /* points to argv[i] of 'script' */
G.global_argv[0] = argv[0];
G.global_argc--;
} /* else -c 'script' ARG0 [ARG1...]: $0 is ARG0 */
block_signals(0); /* 0: called 1st time */
parse_and_run_string(optarg);
goto final_return;
@ -6341,6 +6431,8 @@ int hush_main(int argc, char **argv)
G.last_bg_pid = bb_strtou(optarg, &optarg, 16);
optarg++;
G.last_exitcode = bb_strtou(optarg, &optarg, 16);
optarg++;
builtin_argc = bb_strtou(optarg, &optarg, 16);
# if ENABLE_HUSH_LOOPS
optarg++;
G.depth_of_loop = bb_strtou(optarg, &optarg, 16);
@ -6617,7 +6709,7 @@ static int FAST_FUNC builtin_cd(char **argv)
bb_perror_msg("cd: %s", newdir);
return EXIT_FAILURE;
}
set_cwd();
get_cwd(1);
return EXIT_SUCCESS;
}
@ -6663,17 +6755,16 @@ static int FAST_FUNC builtin_exit(char **argv)
static void print_escaped(const char *s)
{
if (*s == '\'')
goto squote;
do {
if (*s != '\'') {
const char *p;
p = strchrnul(s, '\'');
/* print 'xxxx', possibly just '' */
printf("'%.*s'", (int)(p - s), s);
if (*p == '\0')
break;
s = p;
}
const char *p = strchrnul(s, '\'');
/* print 'xxxx', possibly just '' */
printf("'%.*s'", (int)(p - s), s);
if (*p == '\0')
break;
s = p;
squote:
/* s points to '; print "'''...'''" */
putchar('"');
do putchar('\''); while (*++s == '\'');
@ -6980,13 +7071,14 @@ static int FAST_FUNC builtin_help(char **argv UNUSED_PARAM)
{
const struct built_in_command *x;
printf("\n"
printf(
"Built-in commands:\n"
"------------------\n");
for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
printf("%s\t%s\n", x->cmd, x->descr);
for (x = bltins1; x != &bltins1[ARRAY_SIZE(bltins1)]; x++) {
if (x->descr)
printf("%s\t%s\n", x->cmd, x->descr);
}
printf("\n\n");
bb_putchar('\n');
return EXIT_SUCCESS;
}
#endif
@ -7041,7 +7133,7 @@ static int FAST_FUNC builtin_memleak(char **argv UNUSED_PARAM)
static int FAST_FUNC builtin_pwd(char **argv UNUSED_PARAM)
{
puts(set_cwd());
puts(get_cwd(0));
return EXIT_SUCCESS;
}

2
shell/lash_unused.c
View File

@ -312,7 +312,7 @@ static int builtin_help(struct child_prog UNUSED_PARAM *dummy)
{
const struct built_in_command *x;
printf("\n"
printf(
"Built-in commands:\n"
"------------------\n");
for (x = bltins; x <= &VEC_LAST(bltins); x++) {

2
shell/msh.c
View File

@ -3174,7 +3174,7 @@ static int dohelp(struct op *t UNUSED_PARAM, char **args UNUSED_PARAM)
int col;
const struct builtincmd *x;
printf("\n"
printf(
"Built-in commands:\n"
"------------------\n");