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authorRob Landley <rob@landley.net>2020-01-26 11:12:51 -0600
committerRob Landley <rob@landley.net>2020-01-26 11:12:51 -0600
commitaefc278c02875d6f47e651d0df79734b7aaef74d (patch)
treebeb046f58af3c9acd0c0bdc4fc66178404829ddc
parenta459a19c9c78433a4ec8546dd8dcf14c68d087c7 (diff)
downloadtoybox-aefc278c02875d6f47e651d0df79734b7aaef74d.tar.gz
Implement nommu subshell plumbing, <(command), and fix 2>&1
-rw-r--r--toys/pending/sh.c184
1 files changed, 108 insertions, 76 deletions
diff --git a/toys/pending/sh.c b/toys/pending/sh.c
index 29c030e7..98f5a17e 100644
--- a/toys/pending/sh.c
+++ b/toys/pending/sh.c
@@ -97,7 +97,7 @@ GLOBALS(
char *command;
long lineno;
- char **locals;
+ char **locals, *subshell_env;
struct double_list functions;
unsigned options, jobcnt;
int hfd; // next high filehandle (>= 10)
@@ -243,6 +243,18 @@ int skip_quote(char *s, int dquot, int *depth)
return i;
}
+// add argument to an arg_list
+void add_arg(struct arg_list **list, char *arg)
+{
+ struct arg_list *al;
+
+ if (!list) return;
+ al = xmalloc(sizeof(struct arg_list));
+ al->next = *list;
+ al->arg = arg;
+ *list = al;
+}
+
// quote removal, brace, tilde, parameter/variable, $(command),
// $((arithmetic)), split, path
#define NO_PATH (1<<0)
@@ -337,13 +349,7 @@ TODO this recurses
// Record result.
if (old==new && (flags&FORCE_COPY)) new = xstrdup(new);
- if (old!=new && delete) {
- struct arg_list *al = xmalloc(sizeof(struct arg_list));
-
- al->next = *delete;
- al->arg = new;
- *delete = al;
- }
+ if (old!=new) add_arg(delete, new);
array_add(&arg->v, arg->c++, new);
}
@@ -611,9 +617,34 @@ struct sh_function {
static int parse_line(char *line, struct sh_function *sp);
void free_function(struct sh_function *sp);
-void run_subshell(struct sh_pipeline *sp)
+// TODO: waitpid(WNOHANG) to clean up zombies and catch background& ending
+
+static void subshell_callback(void)
{
- dprintf(2, "TODO: run_subshell\n");
+ TT.subshell_env = xmprintf("@%d,%d=", getpid(), getppid());
+ xsetenv(TT.subshell_env, 0);
+ TT.subshell_env[strlen(TT.subshell_env)-1] = 0;
+}
+
+// Pass environment and command string to child shell
+static int run_subshell(char *str, int len)
+{
+ int pipes[2], pid, i;
+
+ if (pipe(pipes) || 254 != dup2(pipes[0], 254)) return 1;
+ close(pipes[0]);
+
+ fcntl(pipes[1], F_SETFD, FD_CLOEXEC);
+
+ pid = xpopen_setup(0, 0, subshell_callback);
+ close(254);
+
+ if (TT.locals)
+ for (i = 0; TT.locals[i]; i++) dprintf(pipes[1], "%s\n", TT.locals[i]);
+ dprintf(pipes[1], "%.*s\n", len, str);
+ close(pipes[1]);
+
+ return pid;
}
// Expand arguments and perform redirections. Return new process object with
@@ -639,32 +670,27 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen, int *urd)
// Handle <() >() redirectionss
if ((*s == '<' || *s == '>') && s[1] == '(') {
- struct sh_function sf;
int pipes[2], *uu = 0, dd;
// Grab subshell data
- memset(&sf, 0, sizeof(struct sh_function));
- errno = 0;
- if (parse_line(s+1, &sf) || pipe(pipes)) {
+ if (pipe(pipes)) {
perror_msg_raw(s);
- free_function(&sf);
pp->exit = 1;
return pp;
}
-// pipe[1] > pipe[0]->0
-// pipe[0] < pipe[1]->1
// Perform input or output redirect and launch process
dd = *s == '<';
save_redirect(&uu, pipes[dd], dd);
- fcntl(pipes[!dd], F_SETFD, FD_CLOEXEC);
- run_subshell(sf.pipeline); // ignore errors, don't track
+ close(pipes[dd]);
+ run_subshell(s+2, strlen(s+2)-1); // ignore errors, don't track
unredirect(uu);
save_redirect(&urd, -1, pipes[!dd]);
- // Argument is /dev/fd/%d with pipe filehandle
- dlist_add((void *)&pp->delete, ss = xmprintf("/dev/fd/%d", pipes[dd]));
+ // bash uses /dev/fd/%d which requires /dev/fd to be a symlink to
+ // /proc/self/fd so we just produce that directly.
+ add_arg(&pp->delete, ss = xmprintf("/proc/self/fd/%d", pipes[!dd]));
array_add(&pp->arg.v, pp->arg.c++, ss);
continue;
@@ -755,7 +781,7 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen, int *urd)
free(tmp);
if (bad) break;
- // from>=0 means it's fd<<2 (new fd to dup2() after vfork()) plus
+ // from is fd<<2 (new fd to dup2() after vfork()) plus
// 2 if we should close(from>>2) after dup2(from>>2, to),
// 1 if we should close but dup for nofork recovery (ala <&2-)
@@ -772,7 +798,7 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen, int *urd)
}
from = (ss==sss) ? to : atoi(sss);
- if (*ss == '-') saveclose++;
+ saveclose = 2-(*ss == '-');
} else {
// Permissions to open external file with: < > >> <& >& <> >| &>> &>
@@ -804,8 +830,8 @@ static struct sh_process *expand_redir(struct sh_arg *arg, int envlen, int *urd)
setvar(cv, TAKE_MEM);
cv = 0;
}
- if (saveclose && save_redirect(&pp->urd, -1, from)) bad++;
- close(from);
+ if ((saveclose&1) && save_redirect(&pp->urd, -1, from)) bad++;
+ if (!(saveclose&2)) close(from);
if (bad) break;
}
@@ -1382,6 +1408,24 @@ static void dump_state(struct sh_function *sp)
}
}
+void dump_filehandles(char *when)
+{
+ int fd = open("/proc/self/fd", O_RDONLY);
+ DIR *dir = fdopendir(fd);
+ char buf[256];
+
+ if (dir) {
+ struct dirent *dd;
+
+ while ((dd = readdir(dir))) {
+ if (atoi(dd->d_name)!=fd && 0<readlinkat(fd, dd->d_name, buf,sizeof(buf)))
+ dprintf(2, "OPEN %s %d: %s = %s\n", when, getpid(), dd->d_name, buf);
+ }
+ closedir(dir);
+ }
+ close(fd);
+}
+
/* Flow control statements:
if/then/elif/else/fi, for select while until/do/done, case/esac,
@@ -1686,8 +1730,6 @@ static int sh_run(char *new)
struct sh_function scratch;
int rc;
-// TODO: parse with len? (End early?)
-
memset(&scratch, 0, sizeof(struct sh_function));
if (!parse_line(new, &scratch)) run_function(&scratch);
free_function(&scratch);
@@ -1757,57 +1799,48 @@ static void do_prompt(char *prompt)
writeall(2, toybuf, len);
}
+// sanitize environment and handle nommu subshell handoff
void subshell_imports(void)
{
-/*
- // TODO cull local variables because 'env "()=42" env | grep 42' works.
-
- // vfork() means subshells have to export and then re-import locals/functions
- sprintf(toybuf, "(%d#%d)", getpid(), getppid());
- if ((s = getenv(toybuf))) {
- char *from, *to, *ss;
-
- unsetenv(toybuf);
- ss = s;
-
- // Loop through packing \\ until \0
- for (from = to = s; *from; from++, to++) {
- *to = *from;
- if (*from != '\\') continue;
- if (from[1] == '\\' || from[1] == '0') from++;
- if (from[1] != '0') continue;
- *to = 0;
-
- // save chunk
- for (ss = s; ss<to; ss++) {
- if (*ss == '=') {
- // first char of name is variable type ala declare
- if (s+1<ss && strchr("aAilnru", *s)) {
- setvar(ss, *s);
-
- break;
- }
- } else if (!strncmp(ss, "(){", 3)) {
- FILE *ff = fmemopen(s, to-s, "r");
+ int to, from, pid = 0, ppid = 0, len;
+ struct stat st;
+ FILE *fp;
+ char *s;
- while ((new = xgetline(ff, 0))) {
- if ((prompt = parse_line(new, &scratch))<0) break;
- free(new);
- }
- if (!prompt) {
- add_function(s, scratch.pipeline);
- free_function(&scratch);
- break;
- }
- fclose(ff);
- } else if (!isspace(*s) && !ispunct(*s)) continue;
+ // Ensure environ copied and toys.envc set, and clean out illegal entries
+ xunsetenv("");
+ for (to = from = 0; (s = environ[from]); from++) {
- error_exit("bad locals");
- }
- s = from+1;
+ // If nommu subshell gets handoff
+ if (!CFG_TOYBOX_FORK && !toys.stacktop) {
+ len = 0;
+ sscanf(s, "@%d,%d%n", &pid, &ppid, &len);
+ if (len && s[len]) pid = ppid = 0;
}
+
+ // Filter out non-shell variable names
+ for (len = 0; s[len] && ((s[len] == '_') || !ispunct(s[len])); len++);
+ if (s[len] == '=') environ[to++] = environ[from];
}
-*/
+ environ[toys.optc = to] = 0;
+
+//TODO indexed array,associative array,integer,local,nameref,readonly,uppercase
+// if (s+1<ss && strchr("aAilnru", *s)) {
+
+ // sanity check: magic env variable, pipe status
+ if (CFG_TOYBOX_FORK || toys.stacktop || pid != getpid() || ppid != getppid())
+ return;
+ if (fstat(254, &st) || !S_ISFIFO(st.st_mode)) error_exit(0);
+ fcntl(254, F_SETFD, FD_CLOEXEC);
+ fp = fdopen(254, "r");
+
+ // This is not efficient, could array_add the local vars.
+// TODO implicit exec when possible
+ while ((s = xgetline(fp, 0))) to = sh_run(s);
+ fclose(fp);
+
+ toys.exitval = to;
+ xexit();
}
void sh_main(void)
@@ -1936,14 +1969,15 @@ void cd_main(void)
// cancel out . and .. in the string
for (from = to = dd; *from;) {
- while (*from=='/' && from[1]=='/') from++;
- if (*from!='/' || from[1]!='.') *to++ = *from++;
+ if (*from=='/' && from[1]=='/') from++;
+ else if (*from!='/' || from[1]!='.') *to++ = *from++;
else if (!from[2] || from[2]=='/') from += 2;
else if (from[2]=='.' && (!from[3] || from[3]=='/')) {
from += 3;
while (to>dd && *--to != '/');
} else *to++ = *from++;
}
+ if (to == dd) to++;
if (to-dd>1 && to[-1]=='/') to--;
*to = 0;
}
@@ -1960,5 +1994,3 @@ void exit_main(void)
{
exit(*toys.optargs ? atoi(*toys.optargs) : 0);
}
-
-