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-rw-r--r--toys/pending/sh.c324
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));
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-04 03:14:55 +0000