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1479465f GJ |
1 | /* |
2 | * libdpkg - Debian packaging suite library routines | |
3 | * command.c - command execution support | |
4 | * | |
5 | * Copyright © 2010-2012 Guillem Jover <guillem@debian.org> | |
6 | * | |
7 | * This is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program. If not, see <https://www.gnu.org/licenses/>. | |
19 | */ | |
20 | ||
21 | #include <config.h> | |
22 | #include <compat.h> | |
23 | ||
24 | #include <stdarg.h> | |
25 | #include <stdlib.h> | |
26 | #include <unistd.h> | |
27 | ||
28 | #include <dpkg/dpkg.h> | |
29 | #include <dpkg/i18n.h> | |
30 | #include <dpkg/string.h> | |
31 | #include <dpkg/path.h> | |
32 | #include <dpkg/command.h> | |
33 | ||
34 | /** | |
35 | * Initialize a command structure. | |
36 | * | |
37 | * If name is NULL, then the last component of the filename path will be | |
38 | * used to initialize the name member. | |
39 | * | |
40 | * @param cmd The command structure to initialize. | |
41 | * @param filename The filename of the command to execute. | |
42 | * @param name The description of the command to execute. | |
43 | */ | |
44 | void | |
45 | command_init(struct command *cmd, const char *filename, const char *name) | |
46 | { | |
47 | cmd->filename = filename; | |
48 | if (name == NULL) | |
49 | cmd->name = path_basename(filename); | |
50 | else | |
51 | cmd->name = name; | |
52 | cmd->argc = 0; | |
53 | cmd->argv_size = 10; | |
54 | cmd->argv = m_malloc(cmd->argv_size * sizeof(const char *)); | |
55 | cmd->argv[0] = NULL; | |
56 | } | |
57 | ||
58 | /** | |
59 | * Destroy a command structure. | |
60 | * | |
61 | * Free the members managed by the command functions (i.e. the argv pointer | |
62 | * array), and zero all members of a command structure. | |
63 | * | |
64 | * @param cmd The command structure to free. | |
65 | */ | |
66 | void | |
67 | command_destroy(struct command *cmd) | |
68 | { | |
69 | cmd->filename = NULL; | |
70 | cmd->name = NULL; | |
71 | cmd->argc = 0; | |
72 | cmd->argv_size = 0; | |
73 | free(cmd->argv); | |
74 | cmd->argv = NULL; | |
75 | } | |
76 | ||
77 | static void | |
78 | command_grow_argv(struct command *cmd, int need) | |
79 | { | |
80 | /* We need a ghost byte for the NUL character. */ | |
81 | need++; | |
82 | ||
83 | /* Check if we already have enough room. */ | |
84 | if ((cmd->argv_size - cmd->argc) >= need) | |
85 | return; | |
86 | ||
87 | cmd->argv_size = (cmd->argv_size + need) * 2; | |
88 | cmd->argv = m_realloc(cmd->argv, cmd->argv_size * sizeof(const char *)); | |
89 | } | |
90 | ||
91 | /** | |
92 | * Append an argument to the command's argv. | |
93 | * | |
94 | * @param cmd The command structure to act on. | |
95 | * @param arg The argument to append to argv. | |
96 | */ | |
97 | void | |
98 | command_add_arg(struct command *cmd, const char *arg) | |
99 | { | |
100 | command_grow_argv(cmd, 1); | |
101 | ||
102 | cmd->argv[cmd->argc++] = arg; | |
103 | cmd->argv[cmd->argc] = NULL; | |
104 | } | |
105 | ||
106 | /** | |
107 | * Append an argument array to the command's argv. | |
108 | * | |
109 | * @param cmd The command structure to act on. | |
110 | * @param argv The NULL terminated argument array to append to argv. | |
111 | */ | |
112 | void | |
113 | command_add_argl(struct command *cmd, const char **argv) | |
114 | { | |
115 | int i, add_argc = 0; | |
116 | ||
117 | while (argv[add_argc] != NULL) | |
118 | add_argc++; | |
119 | ||
120 | command_grow_argv(cmd, add_argc); | |
121 | ||
122 | for (i = 0; i < add_argc; i++) | |
123 | cmd->argv[cmd->argc++] = argv[i]; | |
124 | ||
125 | cmd->argv[cmd->argc] = NULL; | |
126 | } | |
127 | ||
128 | /** | |
129 | * Append a va_list of argument to the command's argv. | |
130 | * | |
131 | * @param cmd The command structure to act on. | |
132 | * @param args The NULL terminated va_list of argument array to append to argv. | |
133 | */ | |
134 | void | |
135 | command_add_argv(struct command *cmd, va_list args) | |
136 | { | |
137 | va_list args_copy; | |
138 | int i, add_argc = 0; | |
139 | ||
140 | va_copy(args_copy, args); | |
141 | while (va_arg(args_copy, const char *) != NULL) | |
142 | add_argc++; | |
143 | va_end(args_copy); | |
144 | ||
145 | command_grow_argv(cmd, add_argc); | |
146 | ||
147 | for (i = 0; i < add_argc; i++) | |
148 | cmd->argv[cmd->argc++] = va_arg(args, const char *); | |
149 | ||
150 | cmd->argv[cmd->argc] = NULL; | |
151 | } | |
152 | ||
153 | /** | |
154 | * Append a variable list of argument to the command's argv. | |
155 | * | |
156 | * @param cmd The command structure to act on. | |
157 | * @param ... The NULL terminated variable list of argument to append to argv. | |
158 | */ | |
159 | void | |
160 | command_add_args(struct command *cmd, ...) | |
161 | { | |
162 | va_list args; | |
163 | ||
164 | va_start(args, cmd); | |
165 | command_add_argv(cmd, args); | |
166 | va_end(args); | |
167 | } | |
168 | ||
169 | /** | |
170 | * Execute the command specified. | |
171 | * | |
172 | * The command is executed searching the PATH if the filename does not | |
173 | * contain any slashes, or using the full path if it's either a relative or | |
174 | * absolute pathname. This functions does not return. | |
175 | * | |
176 | * @param cmd The command structure to act on. | |
177 | */ | |
178 | void | |
179 | command_exec(struct command *cmd) | |
180 | { | |
181 | execvp(cmd->filename, (char * const *)cmd->argv); | |
182 | ohshite(_("unable to execute %s (%s)"), cmd->name, cmd->filename); | |
183 | } | |
184 | ||
185 | ||
186 | /** | |
187 | * Get a suitable pager. | |
188 | * | |
189 | * @return A string representing a pager. | |
190 | */ | |
191 | const char * | |
192 | command_get_pager(void) | |
193 | { | |
194 | const char *pager; | |
195 | ||
196 | if (!isatty(1)) | |
197 | return CAT; | |
198 | ||
199 | pager = getenv("PAGER"); | |
200 | if (str_is_unset(pager)) | |
201 | pager = DEFAULTPAGER; | |
202 | ||
203 | return pager; | |
204 | } | |
205 | ||
206 | /** | |
207 | * Execute a shell with a possible command. | |
208 | * | |
209 | * @param cmd The command string to execute, if it's NULL an interactive | |
210 | * shell will be executed instead. | |
211 | * @param name The description of the command to execute. | |
212 | */ | |
213 | void | |
214 | command_shell(const char *cmd, const char *name) | |
215 | { | |
216 | const char *shell; | |
217 | const char *mode; | |
218 | ||
219 | if (cmd == NULL) { | |
220 | mode = "-i"; | |
221 | shell = getenv("SHELL"); | |
222 | } else { | |
223 | mode = "-c"; | |
224 | shell = NULL; | |
225 | } | |
226 | ||
227 | if (str_is_unset(shell)) | |
228 | shell = DEFAULTSHELL; | |
229 | ||
230 | execlp(shell, shell, mode, cmd, NULL); | |
231 | ohshite(_("unable to execute %s (%s)"), name, cmd); | |
232 | } |