target/linux/uml/patches-4.9/101-mconsole-exec.patch

   1 #
   2 # Minimalist mconsole exec patch
   3 #
   4 # 3.10 version (with bit more synchronous behavior) by fingon at iki dot fi
   5 # Adaptation to kernel 3.3.8 made by David Fernández (david at dit.upm.es) for
   6 # Starting point: mconsole-exec-2.6.30.patch for kernel 2.6.30
   7 # Author of original patch: Paolo Giarrusso, aka Blaisorblade
   8 #                           (http://www.user-mode-linux.org/~blaisorblade)
   9 #
  10 # Known misfeatures:
  11 #
  12 # - If output is too long, blocks (and breaks horribly)
  13 # (this misfeature from 3.10 patches, when minimalizing the patch;
  14 #  workaround: redirect to a shared filesystem if long output is expected)
  15 #
  16 # - Nothing useful is done with stdin
  17 #
  18 --- a/arch/um/drivers/mconsole.h
  19 +++ b/arch/um/drivers/mconsole.h
  20 @@ -85,6 +85,7 @@ extern void mconsole_cad(struct mc_reque
  21  extern void mconsole_stop(struct mc_request *req);
  22  extern void mconsole_go(struct mc_request *req);
  23  extern void mconsole_log(struct mc_request *req);
  24 +extern void mconsole_exec(struct mc_request *req);
  25  extern void mconsole_proc(struct mc_request *req);
  26  extern void mconsole_stack(struct mc_request *req);
  27
  28 --- a/arch/um/drivers/mconsole_kern.c
  29 +++ b/arch/um/drivers/mconsole_kern.c
  30 @@ -4,6 +4,7 @@
  31   * Licensed under the GPL
  32   */
  33
  34 +#include "linux/kmod.h"
  35  #include <linux/console.h>
  36  #include <linux/ctype.h>
  37  #include <linux/string.h>
  38 @@ -24,6 +25,7 @@
  39  #include <linux/fs.h>
  40  #include <linux/mount.h>
  41  #include <linux/file.h>
  42 +#include <linux/completion.h>
  43  #include <asm/uaccess.h>
  44  #include <asm/switch_to.h>
  45
  46 @@ -121,6 +123,59 @@ void mconsole_log(struct mc_request *req
  47         mconsole_reply(req, "", 0, 0);
  48  }
  49
  50 +void mconsole_exec(struct mc_request *req)
  51 +{
  52 +  struct subprocess_info *sub_info;
  53 +  int res, len;
  54 +  struct file *out;
  55 +  char buf[MCONSOLE_MAX_DATA];
  56 +
  57 +  char *envp[] = {
  58 +    "HOME=/", "TERM=linux",
  59 +    "PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin",
  60 +    NULL
  61 +  };
  62 +  char *argv[] = {
  63 +    "/bin/sh", "-c",
  64 +    req->request.data + strlen("exec "),
  65 +    NULL
  66 +  };
  67 +
  68 +  sub_info = call_usermodehelper_setup("/bin/sh", argv, envp, GFP_ATOMIC, NULL, NULL, NULL);
  69 +  if (sub_info == NULL) {
  70 +    mconsole_reply(req, "call_usermodehelper_setup failed", 1, 0);
  71 +    return;
  72 +  }
  73 +  res = call_usermodehelper_stdoutpipe(sub_info, &out);
  74 +  if (res < 0) {
  75 +    kfree(sub_info);
  76 +    mconsole_reply(req, "call_usermodehelper_stdoutpipe failed", 1, 0);
  77 +    return;
  78 +  }
  79 +
  80 +  res = call_usermodehelper_exec(sub_info, UMH_WAIT_PROC);
  81 +  if (res < 0) {
  82 +    kfree(sub_info);
  83 +    mconsole_reply(req, "call_usermodehelper_exec failed", 1, 0);
  84 +    return;
  85 +  }
  86 +
  87 +  for (;;) {
  88 +    len = out->f_op->read(out, buf, sizeof(buf), &out->f_pos);
  89 +    if (len < 0) {
  90 +      mconsole_reply(req, "reading output failed", 1, 0);
  91 +      break;
  92 +    }
  93 +    if (len == 0)
  94 +      break;
  95 +    mconsole_reply_len(req, buf, len, 0, 1);
  96 +  }
  97 +  fput(out);
  98 +
  99 +  mconsole_reply_len(req, NULL, 0, 0, 0);
 100 +}
 101 +
 102 +
 103  void mconsole_proc(struct mc_request *req)
 104  {
 105         struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
 106 @@ -187,6 +242,7 @@ void mconsole_proc(struct mc_request *re
 107      stop - pause the UML; it will do nothing until it receives a 'go' \n\
 108      go - continue the UML after a 'stop' \n\
 109      log <string> - make UML enter <string> into the kernel log\n\
 110 +    exec <string> - pass <string> to /bin/sh -c synchronously\n\
 111      proc <file> - returns the contents of the UML's /proc/<file>\n\
 112      stack <pid> - returns the stack of the specified pid\n\
 113  "
 114 --- a/arch/um/drivers/mconsole_user.c
 115 +++ b/arch/um/drivers/mconsole_user.c
 116 @@ -30,6 +30,7 @@ static struct mconsole_command commands[
 117         { "stop", mconsole_stop, MCONSOLE_PROC },
 118         { "go", mconsole_go, MCONSOLE_INTR },
 119         { "log", mconsole_log, MCONSOLE_INTR },
 120 +       { "exec", mconsole_exec, MCONSOLE_PROC },
 121         { "proc", mconsole_proc, MCONSOLE_PROC },
 122         { "stack", mconsole_stack, MCONSOLE_INTR },
 123  };
 124 --- a/arch/um/os-Linux/file.c
 125 +++ b/arch/um/os-Linux/file.c
 126 @@ -555,6 +555,8 @@ int os_create_unix_socket(const char *fi
 127
 128         addr.sun_family = AF_UNIX;
 129
 130 +       if (len > sizeof(addr.sun_path))
 131 +               len = sizeof(addr.sun_path);
 132         snprintf(addr.sun_path, len, "%s", file);
 133
 134         err = bind(sock, (struct sockaddr *) &addr, sizeof(addr));
 135 --- a/include/linux/kmod.h
 136 +++ b/include/linux/kmod.h
 137 @@ -62,6 +62,7 @@ struct subprocess_info {
 138         int wait;
 139         int retval;
 140         int (*init)(struct subprocess_info *info, struct cred *new);
 141 +       struct file *stdout;
 142         void (*cleanup)(struct subprocess_info *info);
 143         void *data;
 144  };
 145 @@ -102,4 +103,6 @@ extern int usermodehelper_read_trylock(v
 146  extern long usermodehelper_read_lock_wait(long timeout);
 147  extern void usermodehelper_read_unlock(void);
 148
 149 +int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info, struct file **filp);
 150 +
 151  #endif /* __LINUX_KMOD_H__ */
 152 --- a/kernel/kmod.c
 153 +++ b/kernel/kmod.c
 154 @@ -39,6 +39,7 @@
 155  #include <linux/rwsem.h>
 156  #include <linux/ptrace.h>
 157  #include <linux/async.h>
 158 +#include <linux/pipe_fs_i.h>
 159  #include <asm/uaccess.h>
 160
 161  #include <trace/events/module.h>
 162 @@ -222,6 +223,28 @@ static int call_usermodehelper_exec_asyn
 163         flush_signal_handlers(current, 1);
 164         spin_unlock_irq(&current->sighand->siglock);
 165
 166 +       /* Install output when needed */
 167 +       if (sub_info->stdout) {
 168 +               struct files_struct *f = current->files;
 169 +               struct fdtable *fdt;
 170 +
 171 +               sys_close(1);
 172 +               sys_close(2);
 173 +               get_file(sub_info->stdout);
 174 +               fd_install(1, sub_info->stdout);
 175 +               fd_install(2, sub_info->stdout);
 176 +               spin_lock(&f->file_lock);
 177 +               fdt = files_fdtable(f);
 178 +               __set_bit(1, fdt->open_fds);
 179 +               __clear_bit(1, fdt->close_on_exec);
 180 +               __set_bit(2, fdt->open_fds);
 181 +               __clear_bit(2, fdt->close_on_exec);
 182 +               spin_unlock(&f->file_lock);
 183 +
 184 +               /* disallow core files */
 185 +               current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0};
 186 +       }
 187 +
 188         /*
 189          * Our parent (unbound workqueue) runs with elevated scheduling
 190          * priority. Avoid propagating that into the userspace child.
 191 @@ -540,6 +563,20 @@ struct subprocess_info *call_usermodehel
 192  }
 193  EXPORT_SYMBOL(call_usermodehelper_setup);
 194
 195 +int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info,
 196 +                                 struct file **filp)
 197 +{
 198 +  struct file *f[2];
 199 +
 200 +  if (create_pipe_files(f, 0)<0)
 201 +    return PTR_ERR(f);
 202 +  sub_info->stdout = f[1];
 203 +  *filp = f[0];
 204 +  return 0;
 205 +}
 206 +EXPORT_SYMBOL(call_usermodehelper_stdoutpipe);
 207 +
 208 +
 209  /**
 210   * call_usermodehelper_exec - start a usermode application
 211   * @sub_info: information about the subprocessa