647553a4f
Denys Vlasenko
2009-11-15
Subject
hush: wait for `cmd` to complete, and immediately store its exitcode in $?
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shell/brace.txt +50 -0shell/hush.c +18 -18shell/hush_test/hush-psubst/tick5.right +1 -0shell/hush_test/hush-psubst/tick5.tests +1 -0
shell/brace.txt+50 -0
| @@ -0,0 +1,50 @@ | |
| + | Brace Expansion |
| + | |
| + | Brace expansion is a mechanism by which arbitrary strings may be gener- |
| + | ated. This mechanism is similar to pathname expansion, but the file- |
| + | names generated need not exist. Patterns to be brace expanded take the |
| + | form of an optional preamble, followed by either a series of comma-sep- |
| + | arated strings or a sequence expression between a pair of braces, fol- |
| + | lowed by an optional postscript. The preamble is prefixed to each |
| + | string contained within the braces, and the postscript is then appended |
| + | to each resulting string, expanding left to right. |
| + | |
| + | Brace expansions may be nested. The results of each expanded string |
| + | are not sorted; left to right order is preserved. For example, |
| + | a{d,c,b}e expands into `ade ace abe'. |
| + | |
| + | A sequence expression takes the form {x..y}, where x and y are either |
| + | integers or single characters. When integers are supplied, the expres- |
| + | sion expands to each number between x and y, inclusive. When charac- |
| + | ters are supplied, the expression expands to each character lexico- |
| + | graphically between x and y, inclusive. Note that both x and y must be |
| + | of the same type. |
| + | |
| + | Brace expansion is performed before any other expansions, and any char- |
| + | acters special to other expansions are preserved in the result. It is |
| + | strictly textual. Bash does not apply any syntactic interpretation to |
| + | the context of the expansion or the text between the braces. |
| + | |
| + | A correctly-formed brace expansion must contain unquoted opening and |
| + | closing braces, and at least one unquoted comma or a valid sequence |
| + | expression. Any incorrectly formed brace expansion is left unchanged. |
| + | A { or , may be quoted with a backslash to prevent its being considered |
| + | part of a brace expression. To avoid conflicts with parameter expan- |
| + | sion, the string ${ is not considered eligible for brace expansion. |
| + | |
| + | This construct is typically used as shorthand when the common prefix of |
| + | the strings to be generated is longer than in the above example: |
| + | |
| + | mkdir /usr/local/src/bash/{old,new,dist,bugs} |
| + | or |
| + | chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}} |
| + | |
| + | Brace expansion introduces a slight incompatibility with historical |
| + | versions of sh. sh does not treat opening or closing braces specially |
| + | when they appear as part of a word, and preserves them in the output. |
| + | Bash removes braces from words as a consequence of brace expansion. |
| + | For example, a word entered to sh as file{1,2} appears identically in |
| + | the output. The same word is output as file1 file2 after expansion by |
| + | bash. If strict compatibility with sh is desired, start bash with the |
| + | +B option or disable brace expansion with the +B option to the set com- |
| + | mand |
shell/hush.c+18 -18
| @@ -2287,7 +2287,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char | |
| * expanded result may need to be globbed | |
| * and $IFS-splitted */ | |
| debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch); | |
| - | process_command_subs(&subst_result, arg); |
| + | G.last_exitcode = process_command_subs(&subst_result, arg); |
| debug_printf_subst("SUBST RES '%s'\n", subst_result.data); | |
| val = subst_result.data; | |
| goto store_val; | |
| @@ -3904,7 +3904,7 @@ static NOINLINE int run_pipe(struct pipe *pi) | |
| /* if someone gives us an empty string: `cmd with empty output` */ | |
| if (!argv_expanded[0]) { | |
| debug_leave(); | |
| - | return 0; |
| + | return 0; // or G.last_exitcode? see emptytick.tests |
| } | |
| x = find_builtin(argv_expanded[0]); | |
| @@ -5202,10 +5202,10 @@ static int fetch_heredocs(int heredoc_cnt, struct parse_context *ctx, struct in_ | |
| #if ENABLE_HUSH_TICK | |
| - | static FILE *generate_stream_from_string(const char *s) |
| + | static FILE *generate_stream_from_string(const char *s, pid_t *pid_p) |
| { | |
| - | FILE *pf; |
| - | int pid, channel[2]; |
| + | pid_t pid; |
| + | int channel[2]; |
| # if !BB_MMU | |
| char **to_free; | |
| # endif | |
| @@ -5291,6 +5291,7 @@ static FILE *generate_stream_from_string(const char *s) | |
| } | |
| /* parent */ | |
| + | *pid_p = pid; |
| # if ENABLE_HUSH_FAST | |
| G.count_SIGCHLD++; | |
| //bb_error_msg("[%d] fork in generate_stream_from_string: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD); | |
| @@ -5300,8 +5301,8 @@ static FILE *generate_stream_from_string(const char *s) | |
| free(to_free); | |
| # endif | |
| close(channel[1]); | |
| - | pf = fdopen(channel[0], "r"); |
| - | return pf; |
| + | //TODO: libbb: fdopen_or_die? |
| + | return fdopen(channel[0], "r"); |
| } | |
| /* Return code is exit status of the process that is run. */ | |
| @@ -5309,9 +5310,10 @@ static int process_command_subs(o_string *dest, const char *s) | |
| { | |
| FILE *pf; | |
| struct in_str pipe_str; | |
| - | int ch, eol_cnt; |
| + | pid_t pid; |
| + | int status, ch, eol_cnt; |
| - | pf = generate_stream_from_string(s); |
| + | pf = generate_stream_from_string(s, &pid); |
| if (pf == NULL) | |
| return 1; | |
| close_on_exec_on(fileno(pf)); | |
| @@ -5331,16 +5333,14 @@ static int process_command_subs(o_string *dest, const char *s) | |
| o_addQchr(dest, ch); | |
| } | |
| - | debug_printf("done reading from pipe, pclose()ing\n"); |
| - | /* Note: we got EOF, and we just close the read end of the pipe. |
| - | * We do not wait for the `cmd` child to terminate. bash and ash do. |
| - | * Try these: |
| - | * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec |
| - | * `false`; echo $? - bash outputs "1" |
| - | */ |
| + | debug_printf("done reading from `cmd` pipe, closing it\n"); |
| fclose(pf); | |
| - | debug_printf("closed FILE from child. return 0\n"); |
| - | return 0; |
| + | /* We need to extract exitcode. Test case |
| + | * "true; echo `sleep 1; false` $?" |
| + | * should print 1 */ |
| + | safe_waitpid(pid, &status, 0); |
| + | debug_printf("child exited. returning its exitcode:%d\n", WEXITSTATUS(status)); |
| + | return WEXITSTATUS(status); |
| } | |
| #endif /* ENABLE_HUSH_TICK */ | |
shell/hush_test/hush-psubst/tick5.right+1 -0
| @@ -0,0 +1 @@ | |
| + | 1 |
shell/hush_test/hush-psubst/tick5.tests+1 -0
| @@ -0,0 +1 @@ | |
| + | true; echo `false` $? |