text: /*
   * Copyright (c) 2008, 2009, 2010, 2011, 2013 Nicira, Inc.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <config.h>
  #include "command-line.h"
  #include <getopt.h>
  #include <limits.h>
  #include <stdlib.h>
  #include "ovs-thread.h"
  #include "util.h"
  #include "vlog.h"
  
  VLOG_DEFINE_THIS_MODULE(command_line);
  
  /* Given the GNU-style long options in 'options', returns a string that may be
   * passed to getopt() with the corresponding short options.  The caller is
   * responsible for freeing the string. */
  char *
  long_options_to_short_options(const struct option options[])
  {
      char short_options[UCHAR_MAX * 3 + 1];
      char *p = short_options;
  
      for (; options->name; options++) {
          const struct option *o = options;
          if (o->flag == NULL && o->val > 0 && o->val <= UCHAR_MAX) {
              *p++ = o->val;
              if (o->has_arg == required_argument) {
                  *p++ = ':';
              } else if (o->has_arg == optional_argument) {
                  *p++ = ':';
                  *p++ = ':';
              }
          }
      }
      *p = '\0';
  
      return xstrdup(short_options);
  }
  
  /* Runs the command designated by argv[0] within the command table specified by
   * 'commands', which must be terminated by a command whose 'name' member is a
   * null pointer.
   *
   * Command-line options should be stripped off, so that a typical invocation
   * looks like "run_command(argc - optind, argv + optind, my_commands);". */
  void
  run_command(int argc, char *argv[], const struct command commands[])
  {
      const struct command *p;
  
      if (argc < 1) {
          ovs_fatal(0, "missing command name; use --help for help");
      }
  
      for (p = commands; p->name != NULL; p++) {
          if (!strcmp(p->name, argv[0])) {
              int n_arg = argc - 1;
              if (n_arg < p->min_args) {
                  VLOG_FATAL( "'%s' command requires at least %d arguments",
                              p->name, p->min_args);
              } else if (n_arg > p->max_args) {
                  VLOG_FATAL("'%s' command takes at most %d arguments",
                             p->name, p->max_args);
              } else {
                  p->handler(argc, argv);
                  if (ferror(stdout)) {
                      VLOG_FATAL("write to stdout failed");
                  }
                  if (ferror(stderr)) {
                      VLOG_FATAL("write to stderr failed");
                  }
                  return;
              }
          }
      }
  
      VLOG_FATAL("unknown command '%s'; use --help for help", argv[0]);
  }
  
  /* Process title. */
  
  #ifdef LINUX_DATAPATH
  static char *argv_start;       /* Start of command-line arguments in memory. */
  static size_t argv_size;       /* Number of bytes of command-line arguments. */
  static char *saved_proctitle;  /* Saved command-line arguments. */
  
  /* Prepares the process so that proctitle_set() can later succeed.
   *
   * This modifies the argv[] array so that it no longer points into the memory
   * that it originally does.  Later, proctitle_set() might overwrite that
   * memory.  That means that this function should be called before anything else
   * that accesses the process's argv[] array.  Ideally, it should be called
   * before anything else, period, at the very beginning of program
   * execution.  */
  void
  proctitle_init(int argc, char **argv)
  {
      int i;
  
      assert_single_threaded();
      if (!argc || !argv[0]) {
          /* This situation should never occur, but... */
          return;
      }
  
      /* Specialized version of first loop iteration below. */
      argv_start = argv[0];
      argv_size = strlen(argv[0]) + 1;
      argv[0] = xstrdup(argv[0]);
  
      for (i = 1; i < argc; i++) {
          size_t size = strlen(argv[i]) + 1;
  
          /* Add (argv[i], strlen(argv[i])+1) to (argv_start, argv_size). */
          if (argv[i] + size == argv_start) {
              /* Arguments grow downward in memory. */
              argv_start -= size;
              argv_size += size;
          } else if (argv[i] == argv_start + argv_size) {
              /* Arguments grow upward in memory. */
              argv_size += size;
          } else {
              /* Arguments not contiguous.  (Is this really Linux?) */
          }
  
          /* Copy out the old argument so we can reuse the space. */
          argv[i] = xstrdup(argv[i]);
      }
  }
  
  /* Changes the name of the process, as shown by "ps", to the program name
   * followed by 'format', which is formatted as if by printf(). */
  void
  proctitle_set(const char *format, ...)
  {
      va_list args;
      int n;
  
      if (!argv_start || argv_size < 8) {
          return;
      }
  
      if (!saved_proctitle) {
          saved_proctitle = xmemdup(argv_start, argv_size);
      }
  
      va_start(args, format);
      n = snprintf(argv_start, argv_size, "%s: ", program_name);
      if (n < argv_size) {
          n += vsnprintf(argv_start + n, argv_size - n, format, args);
      }
      if (n >= argv_size) {
          /* The name is too long, so add an ellipsis at the end. */
          strcpy(&argv_start[argv_size - 4], "...");
      } else {
          /* Fill the extra space with null bytes, so that trailing bytes don't
           * show up in the command line. */
          memset(&argv_start[n], '\0', argv_size - n);
      }
      va_end(args);
  }
  
  /* Restores the process's original command line, as seen by "ps". */
  void
  proctitle_restore(void)
  {
      if (saved_proctitle) {
          memcpy(argv_start, saved_proctitle, argv_size);
          free(saved_proctitle);
          saved_proctitle = NULL;
      }
  }
  #else  /* !LINUX_DATAPATH*/
  /* Stubs that don't do anything on non-Linux systems. */
  
  void
  proctitle_init(int argc OVS_UNUSED, char **argv OVS_UNUSED)
  {
  }
  
  #if !(defined(__FreeBSD__) || defined(__NetBSD__))
  /* On these platforms we #define this to setproctitle. */
  void
  proctitle_set(const char *format OVS_UNUSED, ...)
  {
  }
  #endif
  
  void
  proctitle_restore(void)
  {
  }
  #endif  /* !LINUX_DATAPATH */
  