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authorRob Landley <rob@landley.net>2015-09-27 09:03:41 -0500
committerRob Landley <rob@landley.net>2015-09-27 09:03:41 -0500
commit3b51a07e478d64a84e40b3a7c026b2f8566b194b (patch)
treed9cd3570367e49ef7d51f527bdf68984bf2643c7
parent0593b32337b48d60a521922e2355c78750e635d2 (diff)
downloadtoybox-3b51a07e478d64a84e40b3a7c026b2f8566b194b.tar.gz
Another chunk of nommu support, replacing toys.recursion with toys.stacktop.
-rw-r--r--lib/lib.h7
-rw-r--r--lib/xwrap.c18
-rw-r--r--main.c63
-rw-r--r--toys.h26
4 files changed, 70 insertions, 44 deletions
diff --git a/lib/lib.h b/lib/lib.h
index cbac3aa5..d76dcc0c 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -98,6 +98,7 @@ void xputc(char c);
void xflush(void);
void xexec(char **argv);
pid_t xpopen_both(char **argv, int *pipes);
+int xwaitpid(pid_t pid);
int xpclose_both(pid_t pid, int *pipes);
pid_t xpopen(char **argv, int *pipe, int stdout);
pid_t xpclose(pid_t pid, int pipe);
@@ -248,12 +249,12 @@ void names_to_pid(char **names, int (*callback)(pid_t pid, char *name));
// Returning from a function can modify a potentially shared stack,
// so this has to always inline.
-
static inline pid_t xvfork(void)
{
- pid_t p = vfork();
+ pid_t p;
- if (p == -1) perror_exit("vfork");
+ toys.stacktop = 0;
+ if ((p = vfork()) == -1) perror_exit("vfork");
return p;
}
diff --git a/lib/xwrap.c b/lib/xwrap.c
index 80862828..e5dc4826 100644
--- a/lib/xwrap.c
+++ b/lib/xwrap.c
@@ -133,7 +133,8 @@ void xflush(void)
// with a path isn't a builtin, so /bin/sh won't match the builtin sh.
void xexec(char **argv)
{
- if (CFG_TOYBOX && !CFG_TOYBOX_NORECURSE) toy_exec(argv);
+ // Only recurse to builtin when we have multiplexer and !vfork context.
+ if (CFG_TOYBOX && !CFG_TOYBOX_NORECURSE && toys.stacktop) toy_exec(argv);
execvp(argv[0], argv);
perror_msg("exec %s", argv[0]);
@@ -198,17 +199,24 @@ pid_t xpopen_both(char **argv, int *pipes)
return pid;
}
-int xpclose_both(pid_t pid, int *pipes)
+// Wait for child process to exit, then return adjusted exit code.
+int xwaitpid(pid_t pid)
{
- int rc = 127;
+ int status;
+
+ while (-1 == waitpid(pid, &status, 0) && errno == EINTR);
+
+ return WIFEXITED(status) ? WEXITSTATUS(status) : WTERMSIG(status)+127;
+}
+int xpclose_both(pid_t pid, int *pipes)
+{
if (pipes) {
close(pipes[0]);
close(pipes[1]);
}
- waitpid(pid, &rc, 0);
- return WIFEXITED(rc) ? WEXITSTATUS(rc) : WTERMSIG(rc) + 127;
+ return xwaitpid(pid);
}
// Wrapper to xpopen with a pipe for just one of stdin/stdout
diff --git a/main.c b/main.c
index dcd486eb..1e562b06 100644
--- a/main.c
+++ b/main.c
@@ -67,7 +67,7 @@ static const int NEED_OPTIONS =
#include "generated/newtoys.h"
0; // Ends the opts || opts || opts...
-// Subset of init needed by singlemain
+// Setup toybox global state for this command.
static void toy_singleinit(struct toy_list *which, char *argv[])
{
toys.which = which;
@@ -85,7 +85,7 @@ static void toy_singleinit(struct toy_list *which, char *argv[])
if (NEED_OPTIONS && which->options) get_optflags();
else {
toys.optargs = argv+1;
- for (toys.optc=0; toys.optargs[toys.optc]; toys.optc++);
+ for (toys.optc = 0; toys.optargs[toys.optc]; toys.optc++);
}
toys.old_umask = umask(0);
if (!(which->flags & TOYFLAG_UMASK)) umask(toys.old_umask);
@@ -93,8 +93,7 @@ static void toy_singleinit(struct toy_list *which, char *argv[])
toys.toycount = ARRAY_LEN(toy_list);
}
-// Setup toybox global state for this command.
-
+// Full init needed by multiplexer or reentrant calls, calls singleinit at end
void toy_init(struct toy_list *which, char *argv[])
{
// Drop permissions for non-suid commands.
@@ -114,12 +113,12 @@ void toy_init(struct toy_list *which, char *argv[])
}
// Free old toys contents (to be reentrant), but leave rebound if any
-
- if (toys.optargs != toys.argv+1) free(toys.optargs);
+ // don't blank old optargs if our new argc lives in the old optargs.
+ if (argv<toys.optargs || argv>toys.optargs+toys.optc) free(toys.optargs);
memset(&toys, 0, offsetof(struct toy_context, rebound));
- if (toys.recursion > 1) memset(&this, 0, sizeof(this));
+ if (toys.which) memset(&this, 0, sizeof(this));
- // Subset of init needed by singlemain.
+ // Continue to portion of init needed by standalone commands
toy_singleinit(which, argv);
}
@@ -129,14 +128,15 @@ void toy_exec(char *argv[])
{
struct toy_list *which;
- // Return if we can't find it, or need to re-exec to acquire root,
- // or if stack depth is getting silly.
- if (!(which = toy_find(argv[0]))) return;
- if (toys.recursion && (which->flags & TOYFLAG_ROOTONLY) && getuid()) return;
- if (toys.recursion++ > 5) return;
+ // Return if we can't find it (which includes no multiplexer case),
+ if (!(which = toy_find(*argv))) return;
- // don't blank old optargs if our new argc lives in the old optargs.
- if (argv>=toys.optargs && argv<=toys.optargs+toys.optc) toys.optargs = 0;
+ // Return if stack depth getting noticeable (proxy for leaked heap, etc).
+ if (toys.stacktop && labs((char *)toys.stacktop-(char *)&which)>6000)
+ return;
+
+ // Return if we need to re-exec to acquire root via suid bit.
+ if (toys.which && (which->flags&TOYFLAG_ROOTONLY) && getuid()) return;
// Run command
toy_init(which, argv);
@@ -146,16 +146,19 @@ void toy_exec(char *argv[])
// Multiplexer command, first argument is command to run, rest are args to that.
// If first argument starts with - output list of command install paths.
-
void toybox_main(void)
{
static char *toy_paths[]={"usr/","bin/","sbin/",0};
int i, len = 0;
+ // fast path: try to exec immediately.
+ // (Leave toys.which null to disable suid return logic.)
+ if (toys.argv[1]) toy_exec(toys.argv+1);
+
+ // For early error reporting
toys.which = toy_list;
+
if (toys.argv[1]) {
- toys.optc = toys.recursion = 0;
- toy_exec(toys.argv+1);
if (!strcmp("--version", toys.argv[1])) {
xputs(TOYBOX_VERSION);
xexit();
@@ -185,13 +188,27 @@ void toybox_main(void)
int main(int argc, char *argv[])
{
- // We check our own stdout errors, disable sigpipe killer
- signal(SIGPIPE, SIG_IGN);
+ if (!*argv) return 127;
- if (CFG_TOYBOX) {
- // Trim path off of command name
- *argv = basename(*argv);
+ // Snapshot stack location so we can detect recursion depth later.
+ // This is its own block so probe doesn't permanently consume stack.
+ else {
+ int stack;
+
+ toys.stacktop = &stack;
+ }
+ *argv = basename_r(*argv);
+
+ // If nommu can't fork, special reentry path.
+ // Use !stacktop to signal "vfork happened", both before and after xexec()
+ if (!CFG_TOYBOX_FORK) {
+ if (0x80 & **argv) {
+ **argv &= 0x7f;
+ toys.stacktop = 0;
+ }
+ }
+ if (CFG_TOYBOX) {
// Call the multiplexer, adjusting this argv[] to be its' argv[1].
// (It will adjust it back before calling toy_exec().)
toys.argv = argv-1;
diff --git a/toys.h b/toys.h
index 6b539554..d8efa667 100644
--- a/toys.h
+++ b/toys.h
@@ -67,18 +67,6 @@
#include <sys/statfs.h>
#include <sys/sysinfo.h>
-#include "lib/lib.h"
-#include "lib/lsm.h"
-#include "toys/e2fs.h"
-
-// Get list of function prototypes for all enabled command_main() functions.
-
-#define NEWTOY(name, opts, flags) void name##_main(void);
-#define OLDTOY(name, oldname, flags) void oldname##_main(void);
-#include "generated/newtoys.h"
-#include "generated/flags.h"
-#include "generated/globals.h"
-
// These live in main.c
struct toy_list *toy_find(char *name);
@@ -132,7 +120,7 @@ extern struct toy_context {
// This is at the end so toy_init() doesn't zero it.
jmp_buf *rebound; // longjmp here instead of exit when do_rebound set
- int recursion; // How many nested calls to toy_exec()
+ void *stacktop; // nested toy_exec() call count, or -1 if vforked
} toys;
// Two big temporary buffers: one for use by commands, one for library functions
@@ -144,3 +132,15 @@ extern char **environ;
#define GLOBALS(...)
#define ARRAY_LEN(array) (sizeof(array)/sizeof(*array))
+
+#include "lib/lib.h"
+#include "lib/lsm.h"
+#include "toys/e2fs.h"
+
+// Get list of function prototypes for all enabled command_main() functions.
+
+#define NEWTOY(name, opts, flags) void name##_main(void);
+#define OLDTOY(name, oldname, flags) void oldname##_main(void);
+#include "generated/newtoys.h"
+#include "generated/flags.h"
+#include "generated/globals.h"