target/linux/uml/patches-3.10/101-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 diff --git a/arch/um/drivers/mconsole.h b/arch/um/drivers/mconsole.h
  19 index 8b22535..77cc5f7 100644
  20 --- a/arch/um/drivers/mconsole.h
  21 +++ b/arch/um/drivers/mconsole.h
  22 @@ -85,6 +85,7 @@ extern void mconsole_cad(struct mc_request *req);
  23  extern void mconsole_stop(struct mc_request *req);
  24  extern void mconsole_go(struct mc_request *req);
  25  extern void mconsole_log(struct mc_request *req);
  26 +extern void mconsole_exec(struct mc_request *req);
  27  extern void mconsole_proc(struct mc_request *req);
  28  extern void mconsole_stack(struct mc_request *req);
  29
  30 diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
  31 index 3df3bd5..307bf75 100644
  32 --- a/arch/um/drivers/mconsole_kern.c
  33 +++ b/arch/um/drivers/mconsole_kern.c
  34 @@ -4,6 +4,7 @@
  35   * Licensed under the GPL
  36   */
  37
  38 +#include "linux/kmod.h"
  39  #include <linux/console.h>
  40  #include <linux/ctype.h>
  41  #include <linux/string.h>
  42 @@ -24,6 +25,7 @@
  43  #include <linux/fs.h>
  44  #include <linux/mount.h>
  45  #include <linux/file.h>
  46 +#include <linux/completion.h>
  47  #include <asm/uaccess.h>
  48  #include <asm/switch_to.h>
  49
  50 @@ -121,6 +123,59 @@ void mconsole_log(struct mc_request *req)
  51         mconsole_reply(req, "", 0, 0);
  52  }
  53
  54 +void mconsole_exec(struct mc_request *req)
  55 +{
  56 +  struct subprocess_info *sub_info;
  57 +  int res, len;
  58 +  struct file *out;
  59 +  char buf[MCONSOLE_MAX_DATA];
  60 +
  61 +  char *envp[] = {
  62 +    "HOME=/", "TERM=linux",
  63 +    "PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin",
  64 +    NULL
  65 +  };
  66 +  char *argv[] = {
  67 +    "/bin/sh", "-c",
  68 +    req->request.data + strlen("exec "),
  69 +    NULL
  70 +  };
  71 +
  72 +  sub_info = call_usermodehelper_setup("/bin/sh", argv, envp, GFP_ATOMIC, NULL, NULL, NULL);
  73 +  if (sub_info == NULL) {
  74 +    mconsole_reply(req, "call_usermodehelper_setup failed", 1, 0);
  75 +    return;
  76 +  }
  77 +  res = call_usermodehelper_stdoutpipe(sub_info, &out);
  78 +  if (res < 0) {
  79 +    kfree(sub_info);
  80 +    mconsole_reply(req, "call_usermodehelper_stdoutpipe failed", 1, 0);
  81 +    return;
  82 +  }
  83 +
  84 +  res = call_usermodehelper_exec(sub_info, UMH_WAIT_PROC);
  85 +  if (res < 0) {
  86 +    kfree(sub_info);
  87 +    mconsole_reply(req, "call_usermodehelper_exec failed", 1, 0);
  88 +    return;
  89 +  }
  90 +
  91 +  for (;;) {
  92 +    len = out->f_op->read(out, buf, sizeof(buf), &out->f_pos);
  93 +    if (len < 0) {
  94 +      mconsole_reply(req, "reading output failed", 1, 0);
  95 +      break;
  96 +    }
  97 +    if (len == 0)
  98 +      break;
  99 +    mconsole_reply_len(req, buf, len, 0, 1);
 100 +  }
 101 +  fput(out);
 102 +
 103 +  mconsole_reply_len(req, NULL, 0, 0, 0);
 104 +}
 105 +
 106 +
 107  void mconsole_proc(struct mc_request *req)
 108  {
 109         struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
 110 @@ -187,6 +242,7 @@ void mconsole_proc(struct mc_request *req)
 111      stop - pause the UML; it will do nothing until it receives a 'go' \n\
 112      go - continue the UML after a 'stop' \n\
 113      log <string> - make UML enter <string> into the kernel log\n\
 114 +    exec <string> - pass <string> to /bin/sh -c synchronously\n\
 115      proc <file> - returns the contents of the UML's /proc/<file>\n\
 116      stack <pid> - returns the stack of the specified pid\n\
 117  "
 118 diff --git a/arch/um/drivers/mconsole_user.c b/arch/um/drivers/mconsole_user.c
 119 index 9920982..3ed0d32 100644
 120 --- a/arch/um/drivers/mconsole_user.c
 121 +++ b/arch/um/drivers/mconsole_user.c
 122 @@ -30,6 +30,7 @@ static struct mconsole_command commands[] = {
 123         { "stop", mconsole_stop, MCONSOLE_PROC },
 124         { "go", mconsole_go, MCONSOLE_INTR },
 125         { "log", mconsole_log, MCONSOLE_INTR },
 126 +       { "exec", mconsole_exec, MCONSOLE_PROC },
 127         { "proc", mconsole_proc, MCONSOLE_PROC },
 128         { "stack", mconsole_stack, MCONSOLE_INTR },
 129  };
 130 diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
 131 index c17bd6f..1c55fa8 100644
 132 --- a/arch/um/os-Linux/file.c
 133 +++ b/arch/um/os-Linux/file.c
 134 @@ -519,6 +519,8 @@ int os_create_unix_socket(const char *file, int len, int close_on_exec)
 135
 136         addr.sun_family = AF_UNIX;
 137
 138 +       if (len > sizeof(addr.sun_path))
 139 +               len = sizeof(addr.sun_path);
 140         snprintf(addr.sun_path, len, "%s", file);
 141
 142         err = bind(sock, (struct sockaddr *) &addr, sizeof(addr));
 143 diff --git a/include/linux/kmod.h b/include/linux/kmod.h
 144 index 0555cc6..476084d 100644
 145 --- a/include/linux/kmod.h
 146 +++ b/include/linux/kmod.h
 147 @@ -62,6 +62,7 @@ struct subprocess_info {
 148         int wait;
 149         int retval;
 150         int (*init)(struct subprocess_info *info, struct cred *new);
 151 +       struct file *stdout;
 152         void (*cleanup)(struct subprocess_info *info);
 153         void *data;
 154  };
 155 @@ -104,4 +105,6 @@ extern int usermodehelper_read_trylock(void);
 156  extern long usermodehelper_read_lock_wait(long timeout);
 157  extern void usermodehelper_read_unlock(void);
 158
 159 +int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info, struct file **filp);
 160 +
 161  #endif /* __LINUX_KMOD_H__ */
 162 diff --git a/kernel/kmod.c b/kernel/kmod.c
 163 index 8241906..2d7f718 100644
 164 --- a/kernel/kmod.c
 165 +++ b/kernel/kmod.c
 166 @@ -39,6 +39,7 @@
 167  #include <linux/rwsem.h>
 168  #include <linux/ptrace.h>
 169  #include <linux/async.h>
 170 +#include <linux/pipe_fs_i.h>
 171  #include <asm/uaccess.h>
 172
 173  #include <trace/events/module.h>
 174 @@ -206,6 +207,28 @@ static int ____call_usermodehelper(void *data)
 175         flush_signal_handlers(current, 1);
 176         spin_unlock_irq(&current->sighand->siglock);
 177
 178 +        /* Install output when needed */
 179 +        if (sub_info->stdout) {
 180 +                struct files_struct *f = current->files;
 181 +                struct fdtable *fdt;
 182 +
 183 +                sys_close(1);
 184 +                sys_close(2);
 185 +                get_file(sub_info->stdout);
 186 +                fd_install(1, sub_info->stdout);
 187 +                fd_install(2, sub_info->stdout);
 188 +                spin_lock(&f->file_lock);
 189 +                fdt = files_fdtable(f);
 190 +                __set_bit(1, fdt->open_fds);
 191 +                __clear_bit(1, fdt->close_on_exec);
 192 +                __set_bit(2, fdt->open_fds);
 193 +                __clear_bit(2, fdt->close_on_exec);
 194 +                spin_unlock(&f->file_lock);
 195 +
 196 +                /* disallow core files */
 197 +                current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0};
 198 +        }
 199 +
 200         /* We can run anywhere, unlike our parent keventd(). */
 201         set_cpus_allowed_ptr(current, cpu_all_mask);
 202
 203 @@ -551,6 +574,20 @@ struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,
 204  }
 205  EXPORT_SYMBOL(call_usermodehelper_setup);
 206
 207 +int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info,
 208 +                                 struct file **filp)
 209 +{
 210 +  struct file *f[2];
 211 +
 212 +  if (create_pipe_files(f, 0)<0)
 213 +    return PTR_ERR(f);
 214 +  sub_info->stdout = f[1];
 215 +  *filp = f[0];
 216 +  return 0;
 217 +}
 218 +EXPORT_SYMBOL(call_usermodehelper_stdoutpipe);
 219 +
 220 +
 221  /**
 222   * call_usermodehelper_exec - start a usermode application
 223   * @sub_info: information about the subprocessa