OpenWrt – Rev 1
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#
# Minimalist mconsole exec patch
#
# 3.10 version (with bit more synchronous behavior) by fingon at iki dot fi
# Adaptation to kernel 3.3.8 made by David Fernández (david at dit.upm.es) for
# Starting point: mconsole-exec-2.6.30.patch for kernel 2.6.30
# Author of original patch: Paolo Giarrusso, aka Blaisorblade
# (http://www.user-mode-linux.org/~blaisorblade)
#
# Known misfeatures:
#
# - If output is too long, blocks (and breaks horribly)
# (this misfeature from 3.10 patches, when minimalizing the patch;
# workaround: redirect to a shared filesystem if long output is expected)
#
# - Nothing useful is done with stdin
#
--- a/arch/um/drivers/mconsole.h
+++ b/arch/um/drivers/mconsole.h
@@ -85,6 +85,7 @@ extern void mconsole_cad(struct mc_reque
extern void mconsole_stop(struct mc_request *req);
extern void mconsole_go(struct mc_request *req);
extern void mconsole_log(struct mc_request *req);
+extern void mconsole_exec(struct mc_request *req);
extern void mconsole_proc(struct mc_request *req);
extern void mconsole_stack(struct mc_request *req);
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -4,6 +4,7 @@
* Licensed under the GPL
*/
+#include <linux/kmod.h>
#include <linux/console.h>
#include <linux/ctype.h>
#include <linux/string.h>
@@ -26,6 +27,7 @@
#include <linux/mount.h>
#include <linux/file.h>
#include <linux/uaccess.h>
+#include <linux/completion.h>
#include <asm/switch_to.h>
#include <init.h>
@@ -122,6 +124,59 @@ void mconsole_log(struct mc_request *req
mconsole_reply(req, "", 0, 0);
}
+void mconsole_exec(struct mc_request *req)
+{
+ struct subprocess_info *sub_info;
+ int res, len;
+ struct file *out;
+ char buf[MCONSOLE_MAX_DATA];
+
+ char *envp[] = {
+ "HOME=/", "TERM=linux",
+ "PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin",
+ NULL
+ };
+ char *argv[] = {
+ "/bin/sh", "-c",
+ req->request.data + strlen("exec "),
+ NULL
+ };
+
+ sub_info = call_usermodehelper_setup("/bin/sh", argv, envp, GFP_ATOMIC, NULL, NULL, NULL);
+ if (sub_info == NULL) {
+ mconsole_reply(req, "call_usermodehelper_setup failed", 1, 0);
+ return;
+ }
+ res = call_usermodehelper_stdoutpipe(sub_info, &out);
+ if (res < 0) {
+ kfree(sub_info);
+ mconsole_reply(req, "call_usermodehelper_stdoutpipe failed", 1, 0);
+ return;
+ }
+
+ res = call_usermodehelper_exec(sub_info, UMH_WAIT_PROC);
+ if (res < 0) {
+ kfree(sub_info);
+ mconsole_reply(req, "call_usermodehelper_exec failed", 1, 0);
+ return;
+ }
+
+ for (;;) {
+ len = out->f_op->read(out, buf, sizeof(buf), &out->f_pos);
+ if (len < 0) {
+ mconsole_reply(req, "reading output failed", 1, 0);
+ break;
+ }
+ if (len == 0)
+ break;
+ mconsole_reply_len(req, buf, len, 0, 1);
+ }
+ fput(out);
+
+ mconsole_reply_len(req, NULL, 0, 0, 0);
+}
+
+
void mconsole_proc(struct mc_request *req)
{
struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
@@ -183,6 +238,7 @@ void mconsole_proc(struct mc_request *re
stop - pause the UML; it will do nothing until it receives a 'go' \n\
go - continue the UML after a 'stop' \n\
log <string> - make UML enter <string> into the kernel log\n\
+ exec <string> - pass <string> to /bin/sh -c synchronously\n\
proc <file> - returns the contents of the UML's /proc/<file>\n\
stack <pid> - returns the stack of the specified pid\n\
"
--- a/arch/um/drivers/mconsole_user.c
+++ b/arch/um/drivers/mconsole_user.c
@@ -30,6 +30,7 @@ static struct mconsole_command commands[
{ "stop", mconsole_stop, MCONSOLE_PROC },
{ "go", mconsole_go, MCONSOLE_INTR },
{ "log", mconsole_log, MCONSOLE_INTR },
+ { "exec", mconsole_exec, MCONSOLE_PROC },
{ "proc", mconsole_proc, MCONSOLE_PROC },
{ "stack", mconsole_stack, MCONSOLE_INTR },
};
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -555,6 +555,8 @@ int os_create_unix_socket(const char *fi
addr.sun_family = AF_UNIX;
+ if (len > sizeof(addr.sun_path))
+ len = sizeof(addr.sun_path);
snprintf(addr.sun_path, len, "%s", file);
err = bind(sock, (struct sockaddr *) &addr, sizeof(addr));
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -45,4 +45,6 @@ static inline int request_module_nowait(
#define try_then_request_module(x, mod...) (x)
#endif
+int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info, struct file **filp);
+
#endif /* __LINUX_KMOD_H__ */
--- a/include/linux/umh.h
+++ b/include/linux/umh.h
@@ -22,6 +22,7 @@ struct subprocess_info {
const char *path;
char **argv;
char **envp;
+ struct file *stdout;
int wait;
int retval;
int (*init)(struct subprocess_info *info, struct cred *new);
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -25,6 +25,7 @@
#include <linux/ptrace.h>
#include <linux/async.h>
#include <linux/uaccess.h>
+#include <linux/pipe_fs_i.h>
#include <trace/events/module.h>
@@ -70,6 +71,28 @@ static int call_usermodehelper_exec_asyn
flush_signal_handlers(current, 1);
spin_unlock_irq(¤t->sighand->siglock);
+ /* Install output when needed */
+ if (sub_info->stdout) {
+ struct files_struct *f = current->files;
+ struct fdtable *fdt;
+
+ sys_close(1);
+ sys_close(2);
+ get_file(sub_info->stdout);
+ fd_install(1, sub_info->stdout);
+ fd_install(2, sub_info->stdout);
+ spin_lock(&f->file_lock);
+ fdt = files_fdtable(f);
+ __set_bit(1, fdt->open_fds);
+ __clear_bit(1, fdt->close_on_exec);
+ __set_bit(2, fdt->open_fds);
+ __clear_bit(2, fdt->close_on_exec);
+ spin_unlock(&f->file_lock);
+
+ /* disallow core files */
+ current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0};
+ }
+
/*
* Our parent (unbound workqueue) runs with elevated scheduling
* priority. Avoid propagating that into the userspace child.
@@ -393,6 +416,20 @@ struct subprocess_info *call_usermodehel
}
EXPORT_SYMBOL(call_usermodehelper_setup);
+int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info,
+ struct file **filp)
+{
+ struct file *f[2];
+
+ if (create_pipe_files(f, 0) < 0)
+ return PTR_ERR(f);
+
+ sub_info->stdout = f[1];
+ *filp = f[0];
+ return 0;
+}
+EXPORT_SYMBOL(call_usermodehelper_stdoutpipe);
+
/**
* call_usermodehelper_exec - start a usermode application
* @sub_info: information about the subprocessa