diff options
| -rw-r--r-- | toys/pending/sh.c | 324 |
1 files changed, 195 insertions, 129 deletions
diff --git a/toys/pending/sh.c b/toys/pending/sh.c index fc0dfbd9..22ed9a77 100644 --- a/toys/pending/sh.c +++ b/toys/pending/sh.c @@ -119,26 +119,22 @@ GLOBALS( // null terminated array of running processes in pipeline struct sh_process { + struct sh_process *next, *prev; struct string_list *delete; // expanded strings int *urd, pid, exit; // undo redirects, child PID, exit status struct sh_arg arg; } *procs, *proc; } *jobs, *job; - struct sh_process *callback_pp; unsigned jobcnt; - int hfd; // next high filehandle (>= 10) + int hfd, *hfdclose; // next high filehandle (>= 10) ) // ordered for greedy matching, so >&; becomes >& ; not > &; -// these would be const so the array is rodata, but then the compiler -// throws endless warnings. The strings are already rodata and you don't -// need to say const for that, but insecure C++ loons keep working to screw -// up C because its continued existence threatens them somehow. -static char *redirectors[] = {"<<<", "<<-", "<<", "<&", "<>", "<", ">>", +// making these const means I need to typecast the const away later to +// avoid endless warnings. +static const char *redirectors[] = {"<<<", "<<-", "<<", "<&", "<>", "<", ">>", ">&", ">|", ">", "&>>", "&>", 0}; -static char *flowcontrol[] = {";;&", ";;", ";&", ";", "||", "|&", "|", - "&&", "&", "(", ")", 0}; #define SH_NOCLOBBER 1 // set -C @@ -376,9 +372,11 @@ static void unredirect(int *urd) if (!urd) return; for (i = 0; i<*urd; i++) { - // No idea what to do about fd exhaustion here, so Steinbach's Guideline. - dup2(rr[0], rr[1]); - close(rr[0]); + if (rr[1] != -1) { + // No idea what to do about fd exhaustion here, so Steinbach's Guideline. + dup2(rr[0], rr[1]); + close(rr[0]); + } rr += 2; } free(urd); @@ -399,14 +397,6 @@ int next_hfd() return hfd; } -/* -4 cases: -redirect now: from -> to, saving displaced to (+, +) = hfd to -explicitly close (now), saving displaced to (-1, +) = hfd to -redirect saving to, close saving from: (+, +) = hfd to then (-1, +) = hfd to -{var} leak - nothing to save? Except the from open is deferred (+, +) but to == hfd -*/ - // Perform a redirect, saving displaced filehandle to a high (>10) fd // rd is an int array: [0] = count, followed by from/to pairs to restore later. // If from == -1 just save to, else dup from->to after saving to. @@ -417,6 +407,7 @@ int save_redirect(int **rd, int from, int to) // save displaced to, copying to high (>=10) file descriptor to undo later // except if we're saving to environment variable instead (don't undo that) if ((hfd = next_hfd())==-1 || hfd != dup2(to, hfd)) return 1; + fcntl(hfd, F_SETFD, FD_CLOEXEC); // dup "to" if (from != -1 && to != dup2(from, to)) { @@ -436,7 +427,7 @@ int save_redirect(int **rd, int from, int to) // Expand arguments and perform redirections. Return new process object with // expanded args. This can be called from command or block context. -static struct sh_process *expand_redir(struct sh_arg *arg, int envlen) +static struct sh_process *expand_redir(struct sh_arg *arg, int envlen, int *urd) { struct sh_process *pp; char *s, *ss, *sss, *cv = 0; @@ -446,6 +437,7 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen) if (envlen<0 || envlen>=arg->c) return 0; pp = xzalloc(sizeof(struct sh_process)); + pp->urd = urd; // When we redirect, we copy each displaced filehandle to restore it later. @@ -455,7 +447,7 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen) // Is this a redirect? s = prefix, ss = operator sss = ss = (s = arg->v[j]) + redir_prefix(arg->v[j]); - sss += anystart(ss, redirectors); + sss += anystart(ss, (void *)redirectors); if (ss == sss) { // Nope: save/expand argument and loop expand_arg(&pp->arg, s, 0, &pp->delete); @@ -491,6 +483,7 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen) if (!(ss = getvar(s+1, ss-s-2))) break; to = atoi(ss); // TODO trailing garbage? if (save_redirect(&pp->urd, -1, to)) break; + close(to); continue; // record high file descriptor in {to}<from environment variable @@ -556,8 +549,8 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen) break; } - from = (ss=sss) ? to : atoi(sss); - saveclose++; + from = (ss==sss) ? to : atoi(sss); + if (*ss == '-') saveclose++; } else { // Permissions to open external file with: < > >> <& >& <> >| &>> &> @@ -577,7 +570,7 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen) // TODO: is umask respected here? // Open the file - if (-1 == (from = xcreate(sss, from|WARN_ONLY, 777))) break; + if (-1 == (from = xcreate(sss, from|WARN_ONLY, 0666))) break; } // perform redirect, saving displaced "to". @@ -588,8 +581,8 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen) setvar(cv, TAKE_MEM); cv = 0; } - if (saveclose) save_redirect(&pp->urd, from, to); - else close(from); + if (saveclose) save_redirect(&pp->urd, -1, from); + close(from); } if (j != arg->c) { @@ -601,23 +594,14 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen) return pp; } -// callback from xpopen_setup() to close all the high filehandles -// we cached things in so child doesn't inherit unnecessary open fds. -static void redirect_callback(void) -{ - int i, *rr = TT.callback_pp->urd; - - for (i = 0; i<*rr; i++) close(rr[1+2*i]); -} - // Execute a single command -static struct sh_process *run_command(struct sh_arg *arg, int *pipes) +static struct sh_process *run_command(struct sh_arg *arg) { struct sh_process *pp; struct toy_list *tl; // grab environment var assignments, expand arguments and perform redirects - if (!(pp = expand_redir(arg, assign_env(arg)))) return 0; + if (!(pp = expand_redir(arg, assign_env(arg), 0))) return 0; // Do nothing if nothing to do if (pp->exit || !pp->arg.v); @@ -646,18 +630,25 @@ static struct sh_process *run_command(struct sh_arg *arg, int *pipes) if (toys.old_umask) umask(toys.old_umask); memcpy(&toys, &temp, sizeof(struct toy_context)); } else { - TT.callback_pp = pp; - if (-1 == (pp->pid = xpopen_setup(pp->arg.v, pipes, redirect_callback))) + if (-1 == (pp->pid = xpopen_both(pp->arg.v, 0))) perror_msg("%s: vfork", *pp->arg.v); } // cleanup process - llist_traverse(pp->delete, free); unredirect(pp->urd); return pp; } +static void free_process(void *ppp) +{ + struct sh_process *pp = ppp; + + llist_traverse(pp->delete, free); + free(pp); +} + + // parse next word from command line. Returns end, or 0 if need continuation // caller eats leading spaces static char *parse_word(char *start) @@ -711,11 +702,12 @@ static char *parse_word(char *start) // Redirections. 123<<file- parses as 2 args: "123<<" "file-". s = end + redir_prefix(end); - j = anystart(s, redirectors); + j = anystart(s, (void *)redirectors); if (j) s += j; - // Control characters - else s = end + anystart(end, flowcontrol); + // Flow control characters that end pipeline segments + else s = end + anystart(end, (char *[]){";;&", ";;", ";&", ";", "||", + "|&", "|", "&&", "&", "(", ")", 0}); if (s != end) return (end == start) ? s : end; i++; } @@ -757,64 +749,6 @@ struct sh_pipeline { struct sh_arg arg[1]; }; -// run a series of "segment | segment && segment" with redirects. -int run_pipeline(struct sh_pipeline **pl) -{ - struct sh_process *pp; - int rc = 0, pin = 0, pipes[2], *psave; - - // loop through pipeline segments in a block - for (;;) { - struct sh_arg *arg = (*pl)->arg; - - psave = 0; -/* - char *ctl = arg->v[arg->c]; - - // Did the previous pipe segment pipe input into us? - if (pin-->0) save_redir(&psave, pipes[1], 0); - -// TODO job control: & backgrounding -// TODO && || -// TODO | |& -// TODO add redir segment, redir pipes[1] to pipes[0] with close, pop again later -// TODO pipe segments are subshells ala ( ) -// TODO: don't () around single process pipeline, shell otherwise -// this turns into exec for sh -c "echo" -// single pipe segments that _aren't_ builtins run directly, -// compound pipe segments and builtins run via subshell. -// I.E. subshell implicit exec -// TODO we're not running a command, we're running a block stack? -// echo one two three | while read i; do echo hello; done -// TODO free/cleanup partial pipeline on NULL return? - -// TODO run_pipeline has to merge into run_function because pipes don't -// connect commands, they connect arbitrary function chunks. - if (ctl) { - - // pipe? - if (*ctl == '|' && ctl[1] != '|') { - } -*/ - -// TODO: force background? builtin in pipeline implicit () - if (!(pp = run_command(arg, 0))) rc = 0; - else { -// TODO backgrounding - if (pp->pid) pp->exit = xpclose_both(pp->pid, 0); -//wait4(pp); -// TODO -o pipefail - rc = pp->exit; - free(pp); - } - unredirect(psave); - - if ((*pl)->next && !(*pl)->next->type) *pl = (*pl)->next; - else return rc; - } -} - - // scratch space (state held between calls). Don't want to make it global yet // because this could be reentrant. struct sh_function { @@ -1009,7 +943,6 @@ static int parse_line(char *line, struct sh_function *sp) s = arg->v[arg->c] = xstrndup(start, end-start); start = end; if (strchr(";|&", *s)) { - // flow control without a statement is an error if (!arg->c) goto flush; @@ -1018,9 +951,9 @@ static int parse_line(char *line, struct sh_function *sp) arg->v[arg->c] = 0; free(s); s = 0; - } + // ;; and friends only allowed in case statements - if (*s == ';' && (!ex || strcmp(ex, "esac"))) goto flush; + } else if (*s == ';' && (!ex || strcmp(ex, "esac"))) goto flush; last = s; pl->count = -1; @@ -1203,8 +1136,8 @@ static void dump_state(struct sh_function *sp) for (pl = sp->pipeline; pl ; pl = (pl->next == sp->pipeline) ? 0 : pl->next) { for (i = 0; i<pl->arg->c; i++) - printf("arg[%d][%ld]=%s\n", q, i, pl->arg->v[i]); - printf("type=%d term[%d]=%s\n", pl->type, q++, pl->arg->v[pl->arg->c]); + dprintf(2, "arg[%d][%ld]=%s\n", q, i, pl->arg->v[i]); + dprintf(2, "type=%d term[%d]=%s\n", pl->type, q++, pl->arg->v[pl->arg->c]); } } @@ -1215,30 +1148,116 @@ static void dump_state(struct sh_function *sp) */ +static int wait_pipeline(struct sh_process *pp) +{ + int rc = 0; + + for (dlist_terminate(pp); pp; pp = pp->next) { + if (pp->pid) { + // TODO job control: not xwait, handle EINTR ourselves and check signals + pp->exit = xwaitpid(pp->pid); + pp->pid = 0; + } + // TODO handle set -o pipefail here + rc = pp->exit; + } + + return rc; +} + +static int pipe_segments(char *ctl, int *pipes, int **urd) +{ + unredirect(*urd); + *urd = 0; + + // Did the previous pipe segment pipe input into us? + if (pipes[1] != -1) { + save_redirect(urd, pipes[1], 0); + close(pipes[1]); + pipes[1] = -1; + } -// run a shell function, handling flow control statements + // are we piping output to the next segment? + if (ctl && *ctl == '|' && ctl[1] != '|') { + if (pipe(pipes)) { + perror_msg("pipe"); +// TODO record pipeline rc +// TODO check did not reach end of pipeline after loop + return 1; + } + if (pipes[0] != 1) { + save_redirect(urd, pipes[0], 1); + close(pipes[0]); + } + fcntl(pipes[1], F_SETFD, FD_CLOEXEC); + } + + return 0; +} + +static struct sh_pipeline *skip_andor(int rc, struct sh_pipeline *pl) +{ + char *ctl = pl->arg->v[pl->arg->c]; + + // For && and || skip pipeline segment(s) based on return code + while (ctl && ((!strcmp(ctl, "&&") && rc) || (!strcmp(ctl, "||") && !rc))) { + if (!pl->next || pl->next->type == 2 || pl->next->type == 3) break; + pl = pl->type ? block_end(pl) : pl->next; + ctl = pl ? pl->arg->v[pl->arg->c] : 0; + } + + return pl; +} + +// run a parsed shell function. Handle flow control blocks and characters, +// setup pipes and block redirection, break/continue, call builtins, +// vfork/exec external commands. static void run_function(struct sh_function *sp) { struct sh_pipeline *pl = sp->pipeline, *end; struct blockstack { struct blockstack *next; struct sh_pipeline *start, *end; - int run, loop, *redir; - + struct sh_process *pin; // processes piping into this block + int run, loop, *urd, pout; struct sh_arg farg; // for/select arg stack struct string_list *fdelete; // farg's cleanup list char *fvar; // for/select's iteration variable name } *blk = 0, *new; + struct sh_process *pplist = 0; // processes piping into current level + int *urd = 0, pipes[2] = {-1, -1}; long i; - // iterate through the commands +// TODO can't free sh_process delete until ready to dispose else no debug output + + // iterate through pipeline segments while (pl) { char *s = *pl->arg->v, *ss = pl->arg->v[1]; -//dprintf(2, "s=%s %s %d %s %d\n", s, ss, pl->type, blk ? blk->start->arg->v[0] : "X", blk ? blk->run : 0); - // Normal executable statement? + struct sh_process *pp = 0; + + // Is this an executable segment? if (!pl->type) { -// TODO: break & is supported? Seriously? Also break > potato -// TODO: break multiple aguments + struct sh_arg *arg = pl->arg; + char *ctl = arg->v[arg->c]; + + // Skip disabled block + if (blk && !blk->run) { + while (pl->next && !pl->next->type) pl = pl->next; + continue; + } + + if (pipe_segments(ctl, pipes, &urd)) break; + + // If we just started a new pipeline, implicit parentheses (subshell) + +// TODO: "echo | read i" is backgroundable with ctrl-Z despite read = builtin. +// probably have to inline run_command here to do that? Implicit () +// also "X=42 | true; echo $X" doesn't get X. + + // TODO: bash supports "break &" and "break > file". No idea why. + + // Is it a flow control jump? These aren't handled as normal builtins + // because they move *pl to other pipeline segments which is local here. if (!strcmp(s, "break") || !strcmp(s, "continue")) { // How many layers to peel off? @@ -1256,7 +1275,14 @@ static void run_function(struct sh_function *sp) break; } pl = blk->end; +// TODO collate end_block logic + + // if ending a block, free, cleanup redirects, and pop stack. + llist_traverse(blk->fdelete, free); + unredirect(blk->urd); + if (pipes[1]) close(pipes[1]); + pipes[1] = blk->pout; free(llist_pop(&blk)); } if (i) { @@ -1264,17 +1290,27 @@ static void run_function(struct sh_function *sp) break; } pl = pl->next; - continue; + + // Parse and run next command + } else { + +// TODO: "echo | read i" is backgroundable with ctrl-Z despite read = builtin. +// probably have to inline run_command here to do that? Implicit () +// also "X=42 | true; echo $X" doesn't get X. + + if (!(pp = run_command(arg))) break; + dlist_add_nomalloc((void *)&pplist, (void *)pp); } -// inherit redirects? -// returns last statement of pipeline - if (!blk) toys.exitval = run_pipeline(&pl); - else if (blk->run) toys.exitval = run_pipeline(&pl); - else while (pl->next && !pl->next->type) pl = pl->next; + if (pipes[1] == -1) { + toys.exitval = wait_pipeline(pplist); + llist_traverse(pplist, free_process); + pplist = 0; + pl = skip_andor(toys.exitval, pl); + } - // Starting a new block? + // Start of flow control block? } else if (pl->type == 1) { // are we entering this block (rather than looping back to it)? @@ -1288,6 +1324,9 @@ static void run_function(struct sh_function *sp) continue; } + // If previous piped into this block, save context until block end + if (pipe_segments(0, pipes, &urd)) break; + // It's a new block we're running, save context and add it to the stack. new = xzalloc(sizeof(*blk)); new->next = blk; @@ -1295,11 +1334,28 @@ static void run_function(struct sh_function *sp) blk->start = pl; blk->end = end; blk->run = 1; -// TODO perform block end redirects to blk->redir + + // save context until block end + blk->pout = pipes[1]; + blk->urd = urd; + urd = 0; + pipes[1] = -1; + + // Perform redirects listed at end of block + pp = expand_redir(blk->end->arg, 0, blk->urd); + if (pp) { + blk->urd = pp->urd; + if (pp->arg.c) syntax_err("unexpected %s", *pp->arg.v); + llist_traverse(pp->delete, free); + if (pp->arg.c) break; + free(pp); + } } // What flow control statement is this? +// TODO ( subshell + // if/then/elif/else/fi, while until/do/done - no special handling needed // for select/do/done @@ -1328,7 +1384,7 @@ case/esac function/} */ - // gearshift from block start to block body + // gearshift from block start to block body (end of flow control test) } else if (pl->type == 2) { // Handle if statement @@ -1348,7 +1404,7 @@ dprintf(2, "TODO skipped running for((;;)), need math parser\n"); TAKE_MEM); } - // end of block + // end of block, may have trailing redirections and/or pipe } else if (pl->type == 3) { // repeating block? @@ -1357,20 +1413,30 @@ dprintf(2, "TODO skipped running for((;;)), need math parser\n"); continue; } - // if ending a block, pop stack. +// TODO goto "break" above instead of copying it here? + // if ending a block, free, cleanup redirects, and pop stack. + // needing to unredirect(urd) or close(pipes[1]) here would be syntax err llist_traverse(blk->fdelete, free); + unredirect(blk->urd); + pipes[1] = blk->pout; free(llist_pop(&blk)); - -// TODO unwind redirects (cleanup blk->redir) - } else if (pl->type == 'f') pl = add_function(s, pl); pl = pl->next; } + // did we exit with unfinished stuff? + if (pipes[1] != -1) close(pipes[1]); + if (pplist) { + toys.exitval = wait_pipeline(pplist); + llist_traverse(pplist, free_process); + } + unredirect(urd); + // Cleanup from syntax_err(); while (blk) { llist_traverse(blk->fdelete, free); + unredirect(blk->urd); free(llist_pop(&blk)); } |