2 * Copyright (c) 2008, 2009, 2010 Nicira Networks.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "command-line.h"
24 /* Given the GNU-style long options in 'options', returns a string that may be
25 * passed to getopt() with the corresponding short options. The caller is
26 * responsible for freeing the string. */
28 long_options_to_short_options(const struct option options[])
30 char short_options[UCHAR_MAX * 3 + 1];
31 char *p = short_options;
33 for (; options->name; options++) {
34 const struct option *o = options;
35 if (o->flag == NULL && o->val > 0 && o->val <= UCHAR_MAX) {
37 if (o->has_arg == required_argument) {
39 } else if (o->has_arg == optional_argument) {
47 return xstrdup(short_options);
50 /* Runs the command designated by argv[0] within the command table specified by
51 * 'commands', which must be terminated by a command whose 'name' member is a
54 * Command-line options should be stripped off, so that a typical invocation
55 * looks like "run_command(argc - optind, argv + optind, my_commands);". */
57 run_command(int argc, char *argv[], const struct command commands[])
59 const struct command *p;
62 ovs_fatal(0, "missing command name; use --help for help");
65 for (p = commands; p->name != NULL; p++) {
66 if (!strcmp(p->name, argv[0])) {
68 if (n_arg < p->min_args) {
69 ovs_fatal(0, "'%s' command requires at least %d arguments",
70 p->name, p->min_args);
71 } else if (n_arg > p->max_args) {
72 ovs_fatal(0, "'%s' command takes at most %d arguments",
73 p->name, p->max_args);
75 p->handler(argc, argv);
77 ovs_fatal(0, "write to stdout failed");
80 ovs_fatal(0, "write to stderr failed");
87 ovs_fatal(0, "unknown command '%s'; use --help for help", argv[0]);
93 static char *argv_start; /* Start of command-line arguments in memory. */
94 static size_t argv_size; /* Number of bytes of command-line arguments. */
95 static char *saved_proctitle; /* Saved command-line arguments. */
97 /* Prepares the process so that proctitle_set() can later succeed.
99 * This modifies the argv[] array so that it no longer points into the memory
100 * that it originally does. Later, proctitle_set() might overwrite that
101 * memory. That means that this function should be called before anything else
102 * that accesses the process's argv[] array. Ideally, it should be called
103 * before anything else, period, at the very beginning of program
106 proctitle_init(int argc, char **argv)
110 if (!argc || !argv[0]) {
111 /* This situation should never occur, but... */
115 /* Specialized version of first loop iteration below. */
116 argv_start = argv[0];
117 argv_size = strlen(argv[0]) + 1;
118 argv[0] = xstrdup(argv[0]);
120 for (i = 1; i < argc; i++) {
121 size_t size = strlen(argv[i]) + 1;
123 /* Add (argv[i], strlen(argv[i])+1) to (argv_start, argv_size). */
124 if (argv[i] + size == argv_start) {
125 /* Arguments grow downward in memory. */
128 } else if (argv[i] == argv_start + argv_size) {
129 /* Arguments grow upward in memory. */
132 /* Arguments not contiguous. (Is this really Linux?) */
135 /* Copy out the old argument so we can reuse the space. */
136 argv[i] = xstrdup(argv[i]);
140 /* Changes the name of the process, as shown by "ps", to 'format', which is
141 * formatted as if by printf(). */
143 proctitle_set(const char *format, ...)
148 if (!argv_start || argv_size < 8) {
152 if (!saved_proctitle) {
153 saved_proctitle = xmemdup(argv_start, argv_size);
156 va_start(args, format);
157 n = vsnprintf(argv_start, argv_size, format, args);
158 if (n >= argv_size) {
159 /* The name is too long, so add an ellipsis at the end. */
160 strcpy(&argv_start[argv_size - 4], "...");
162 /* Fill the extra space with null bytes, so that trailing bytes don't
163 * show up in the command line. */
164 memset(&argv_start[n], '\0', argv_size - n);
169 /* Restores the process's original command line, as seen by "ps". */
171 proctitle_restore(void)
173 if (saved_proctitle) {
174 memcpy(argv_start, saved_proctitle, argv_size);
175 free(saved_proctitle);
176 saved_proctitle = NULL;
179 #else /* !__linux__ */
180 /* Stubs that don't do anything on non-Linux systems. */
183 proctitle_init(int argc OVS_UNUSED, char **argv OVS_UNUSED)
188 proctitle_set(const char *format OVS_UNUSED, ...)
193 proctitle_restore(void)
196 #endif /* !__linux__ */