[PATCH] uml: separate libc-dependent helper code
The serial UML OS-abstraction layer patch (um/kernel dir).
This moves all systemcalls from helper.c file under os-Linux dir
Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
new file mode 100644
index 0000000..36cc847
--- /dev/null
+++ b/arch/um/os-Linux/helper.c
@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sched.h>
+#include <sys/signal.h>
+#include <sys/wait.h>
+#include "user.h"
+#include "kern_util.h"
+#include "user_util.h"
+#include "os.h"
+
+struct helper_data {
+ void (*pre_exec)(void*);
+ void *pre_data;
+ char **argv;
+ int fd;
+};
+
+/* Debugging aid, changed only from gdb */
+int helper_pause = 0;
+
+static void helper_hup(int sig)
+{
+}
+
+static int helper_child(void *arg)
+{
+ struct helper_data *data = arg;
+ char **argv = data->argv;
+ int errval;
+
+ if(helper_pause){
+ signal(SIGHUP, helper_hup);
+ pause();
+ }
+ if(data->pre_exec != NULL)
+ (*data->pre_exec)(data->pre_data);
+ execvp(argv[0], argv);
+ errval = errno;
+ printk("execvp of '%s' failed - errno = %d\n", argv[0], errno);
+ os_write_file(data->fd, &errval, sizeof(errval));
+ kill(os_getpid(), SIGKILL);
+ return(0);
+}
+
+/* Returns either the pid of the child process we run or -E* on failure.
+ * XXX The alloc_stack here breaks if this is called in the tracing thread */
+int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv,
+ unsigned long *stack_out)
+{
+ struct helper_data data;
+ unsigned long stack, sp;
+ int pid, fds[2], ret, n;
+
+ if((stack_out != NULL) && (*stack_out != 0))
+ stack = *stack_out;
+ else stack = alloc_stack(0, um_in_interrupt());
+ if(stack == 0)
+ return(-ENOMEM);
+
+ ret = os_pipe(fds, 1, 0);
+ if(ret < 0){
+ printk("run_helper : pipe failed, ret = %d\n", -ret);
+ goto out_free;
+ }
+
+ ret = os_set_exec_close(fds[1], 1);
+ if(ret < 0){
+ printk("run_helper : setting FD_CLOEXEC failed, ret = %d\n",
+ -ret);
+ goto out_close;
+ }
+
+ sp = stack + page_size() - sizeof(void *);
+ data.pre_exec = pre_exec;
+ data.pre_data = pre_data;
+ data.argv = argv;
+ data.fd = fds[1];
+ pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data);
+ if(pid < 0){
+ ret = -errno;
+ printk("run_helper : clone failed, errno = %d\n", errno);
+ goto out_close;
+ }
+
+ close(fds[1]);
+ fds[1] = -1;
+
+ /*Read the errno value from the child.*/
+ n = os_read_file(fds[0], &ret, sizeof(ret));
+ if(n < 0){
+ printk("run_helper : read on pipe failed, ret = %d\n", -n);
+ ret = n;
+ kill(pid, SIGKILL);
+ CATCH_EINTR(waitpid(pid, NULL, 0));
+ }
+ else if(n != 0){
+ CATCH_EINTR(n = waitpid(pid, NULL, 0));
+ ret = -errno;
+ } else {
+ ret = pid;
+ }
+
+out_close:
+ if (fds[1] != -1)
+ close(fds[1]);
+ close(fds[0]);
+out_free:
+ if(stack_out == NULL)
+ free_stack(stack, 0);
+ else *stack_out = stack;
+ return(ret);
+}
+
+int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
+ unsigned long *stack_out, int stack_order)
+{
+ unsigned long stack, sp;
+ int pid, status, err;
+
+ stack = alloc_stack(stack_order, um_in_interrupt());
+ if(stack == 0) return(-ENOMEM);
+
+ sp = stack + (page_size() << stack_order) - sizeof(void *);
+ pid = clone(proc, (void *) sp, flags | SIGCHLD, arg);
+ if(pid < 0){
+ err = -errno;
+ printk("run_helper_thread : clone failed, errno = %d\n",
+ errno);
+ return err;
+ }
+ if(stack_out == NULL){
+ CATCH_EINTR(pid = waitpid(pid, &status, 0));
+ if(pid < 0){
+ err = -errno;
+ printk("run_helper_thread - wait failed, errno = %d\n",
+ errno);
+ pid = err;
+ }
+ if(!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
+ printk("run_helper_thread - thread returned status "
+ "0x%x\n", status);
+ free_stack(stack, stack_order);
+ }
+ else *stack_out = stack;
+ return(pid);
+}
+
+int helper_wait(int pid)
+{
+ int ret;
+
+ CATCH_EINTR(ret = waitpid(pid, NULL, WNOHANG));
+ if(ret < 0){
+ ret = -errno;
+ printk("helper_wait : waitpid failed, errno = %d\n", errno);
+ }
+ return(ret);
+}