1 // Functions used for implementing the ulimit builtin.
2 #include "config.h" // IWYU pragma: keep
3
4 #include <sys/resource.h>
5
6 #include <cerrno>
7 #include <cstddef>
8
9 #include "builtin.h"
10 #include "common.h"
11 #include "fallback.h" // IWYU pragma: keep
12 #include "io.h"
13 #include "wgetopt.h"
14 #include "wutil.h" // IWYU pragma: keep
15
16 class parser_t;
17
18 /// Struct describing a resource limit.
19 struct resource_t {
20 int resource; // resource ID
21 const wchar_t *desc; // description of resource
22 wchar_t switch_char; // switch used on commandline to specify resource
23 int multiplier; // the implicit multiplier used when setting getting values
24 };
25
26 /// Array of resource_t structs, describing all known resource types.
27 static const struct resource_t resource_arr[] = {
28 {RLIMIT_CORE, L"Maximum size of core files created", L'c', 1024},
29 {RLIMIT_DATA, L"Maximum size of a process’s data segment", L'd', 1024},
30 {RLIMIT_FSIZE, L"Maximum size of files created by the shell", L'f', 1024},
31 #ifdef RLIMIT_MEMLOCK
32 {RLIMIT_MEMLOCK, L"Maximum size that may be locked into memory", L'l', 1024},
33 #endif
34 #ifdef RLIMIT_RSS
35 {RLIMIT_RSS, L"Maximum resident set size", L'm', 1024},
36 #endif
37 {RLIMIT_NOFILE, L"Maximum number of open file descriptors", L'n', 1},
38 {RLIMIT_STACK, L"Maximum stack size", L's', 1024},
39 {RLIMIT_CPU, L"Maximum amount of cpu time in seconds", L't', 1},
40 #ifdef RLIMIT_NPROC
41 {RLIMIT_NPROC, L"Maximum number of processes available to a single user", L'u', 1},
42 #endif
43 #ifdef RLIMIT_AS
44 {RLIMIT_AS, L"Maximum amount of virtual memory available to the shell", L'v', 1024},
45 #endif
46 {0, nullptr, 0, 0}};
47
48 /// Get the implicit multiplication factor for the specified resource limit.
get_multiplier(int what)49 static int get_multiplier(int what) {
50 for (int i = 0; resource_arr[i].desc; i++) {
51 if (resource_arr[i].resource == what) {
52 return resource_arr[i].multiplier;
53 }
54 }
55 return -1;
56 }
57
58 /// Return the value for the specified resource limit. This function does _not_ multiply the limit
59 /// value by the multiplier constant used by the commandline ulimit.
get(int resource,int hard)60 static rlim_t get(int resource, int hard) {
61 struct rlimit ls;
62
63 getrlimit(resource, &ls);
64
65 return hard ? ls.rlim_max : ls.rlim_cur;
66 }
67
68 /// Print the value of the specified resource limit.
print(int resource,int hard,io_streams_t & streams)69 static void print(int resource, int hard, io_streams_t &streams) {
70 rlim_t l = get(resource, hard);
71
72 if (l == RLIM_INFINITY)
73 streams.out.append(L"unlimited\n");
74 else
75 streams.out.append_format(L"%d\n", l / get_multiplier(resource));
76 }
77
78 /// Print values of all resource limits.
print_all(int hard,io_streams_t & streams)79 static void print_all(int hard, io_streams_t &streams) {
80 int i;
81 int w = 0;
82
83 for (i = 0; resource_arr[i].desc; i++) {
84 w = std::max(w, fish_wcswidth(resource_arr[i].desc));
85 }
86
87 for (i = 0; resource_arr[i].desc; i++) {
88 struct rlimit ls;
89 rlim_t l;
90 getrlimit(resource_arr[i].resource, &ls);
91 l = hard ? ls.rlim_max : ls.rlim_cur;
92
93 const wchar_t *unit =
94 ((resource_arr[i].resource == RLIMIT_CPU)
95 ? L"(seconds, "
96 : (get_multiplier(resource_arr[i].resource) == 1 ? L"(" : L"(kB, "));
97
98 streams.out.append_format(L"%-*ls %10ls-%lc) ", w, resource_arr[i].desc, unit,
99 resource_arr[i].switch_char);
100
101 if (l == RLIM_INFINITY) {
102 streams.out.append(L"unlimited\n");
103 } else {
104 streams.out.append_format(L"%d\n", l / get_multiplier(resource_arr[i].resource));
105 }
106 }
107 }
108
109 /// Returns the description for the specified resource limit.
get_desc(int what)110 static const wchar_t *get_desc(int what) {
111 int i;
112
113 for (i = 0; resource_arr[i].desc; i++) {
114 if (resource_arr[i].resource == what) {
115 return resource_arr[i].desc;
116 }
117 }
118 return L"Not a resource";
119 }
120
121 /// Set the new value of the specified resource limit. This function does _not_ multiply the limit
122 // value by the multiplier constant used by the commandline ulimit.
set_limit(int resource,int hard,int soft,rlim_t value,io_streams_t & streams)123 static int set_limit(int resource, int hard, int soft, rlim_t value, io_streams_t &streams) {
124 struct rlimit ls;
125
126 getrlimit(resource, &ls);
127 if (hard) ls.rlim_max = value;
128 if (soft) {
129 ls.rlim_cur = value;
130
131 // Do not attempt to set the soft limit higher than the hard limit.
132 if ((value == RLIM_INFINITY && ls.rlim_max != RLIM_INFINITY) ||
133 (value != RLIM_INFINITY && ls.rlim_max != RLIM_INFINITY && value > ls.rlim_max)) {
134 ls.rlim_cur = ls.rlim_max;
135 }
136 }
137
138 if (setrlimit(resource, &ls)) {
139 if (errno == EPERM) {
140 streams.err.append_format(
141 L"ulimit: Permission denied when changing resource of type '%ls'\n",
142 get_desc(resource));
143 } else {
144 builtin_wperror(L"ulimit", streams);
145 }
146 return STATUS_CMD_ERROR;
147 }
148 return STATUS_CMD_OK;
149 }
150
151 /// The ulimit builtin, used for setting resource limits.
builtin_ulimit(parser_t & parser,io_streams_t & streams,const wchar_t ** argv)152 maybe_t<int> builtin_ulimit(parser_t &parser, io_streams_t &streams, const wchar_t **argv) {
153 const wchar_t *cmd = argv[0];
154 int argc = builtin_count_args(argv);
155 bool report_all = false;
156 bool hard = false;
157 bool soft = false;
158 int what = RLIMIT_FSIZE;
159
160 static const wchar_t *const short_options = L":HSacdflmnstuvh";
161 static const struct woption long_options[] = {
162 {L"all", no_argument, nullptr, 'a'},
163 {L"hard", no_argument, nullptr, 'H'},
164 {L"soft", no_argument, nullptr, 'S'},
165 {L"core-size", no_argument, nullptr, 'c'},
166 {L"data-size", no_argument, nullptr, 'd'},
167 {L"file-size", no_argument, nullptr, 'f'},
168 {L"lock-size", no_argument, nullptr, 'l'},
169 {L"resident-set-size", no_argument, nullptr, 'm'},
170 {L"file-descriptor-count", no_argument, nullptr, 'n'},
171 {L"stack-size", no_argument, nullptr, 's'},
172 {L"cpu-time", no_argument, nullptr, 't'},
173 {L"process-count", no_argument, nullptr, 'u'},
174 {L"virtual-memory-size", no_argument, nullptr, 'v'},
175 {L"help", no_argument, nullptr, 'h'},
176 {nullptr, 0, nullptr, 0}};
177
178 int opt;
179 wgetopter_t w;
180 while ((opt = w.wgetopt_long(argc, argv, short_options, long_options, nullptr)) != -1) {
181 switch (opt) {
182 case 'a': {
183 report_all = true;
184 break;
185 }
186 case 'H': {
187 hard = true;
188 break;
189 }
190 case 'S': {
191 soft = true;
192 break;
193 }
194 case 'c': {
195 what = RLIMIT_CORE;
196 break;
197 }
198 case 'd': {
199 what = RLIMIT_DATA;
200 break;
201 }
202 case 'f': {
203 what = RLIMIT_FSIZE;
204 break;
205 }
206 #ifdef RLIMIT_MEMLOCK
207 case 'l': {
208 what = RLIMIT_MEMLOCK;
209 break;
210 }
211 #endif
212 #ifdef RLIMIT_RSS
213 case 'm': {
214 what = RLIMIT_RSS;
215 break;
216 }
217 #endif
218 case 'n': {
219 what = RLIMIT_NOFILE;
220 break;
221 }
222 case 's': {
223 what = RLIMIT_STACK;
224 break;
225 }
226 case 't': {
227 what = RLIMIT_CPU;
228 break;
229 }
230 #ifdef RLIMIT_NPROC
231 case 'u': {
232 what = RLIMIT_NPROC;
233 break;
234 }
235 #endif
236 #ifdef RLIMIT_AS
237 case 'v': {
238 what = RLIMIT_AS;
239 break;
240 }
241 #endif
242 case 'h': {
243 builtin_print_help(parser, streams, cmd);
244 return STATUS_CMD_OK;
245 }
246 case ':': {
247 builtin_missing_argument(parser, streams, cmd, argv[w.woptind - 1]);
248 return STATUS_INVALID_ARGS;
249 }
250 case '?': {
251 builtin_unknown_option(parser, streams, cmd, argv[w.woptind - 1]);
252 return STATUS_INVALID_ARGS;
253 }
254 default: {
255 DIE("unexpected retval from wgetopt_long");
256 }
257 }
258 }
259
260 if (report_all) {
261 print_all(hard, streams);
262 return STATUS_CMD_OK;
263 }
264
265 int arg_count = argc - w.woptind;
266 if (arg_count == 0) {
267 // Show current limit value.
268 print(what, hard, streams);
269 return STATUS_CMD_OK;
270 } else if (arg_count != 1) {
271 streams.err.append_format(BUILTIN_ERR_TOO_MANY_ARGUMENTS, cmd);
272 builtin_print_error_trailer(parser, streams.err, cmd);
273 return STATUS_INVALID_ARGS;
274 }
275
276 // Change current limit value.
277 if (!hard && !soft) {
278 // Set both hard and soft limits if neither was specified.
279 hard = soft = true;
280 }
281
282 rlim_t new_limit;
283 if (*argv[w.woptind] == L'\0') {
284 streams.err.append_format(_(L"%ls: New limit cannot be an empty string\n"), cmd);
285 builtin_print_error_trailer(parser, streams.err, cmd);
286 return STATUS_INVALID_ARGS;
287 } else if (wcscasecmp(argv[w.woptind], L"unlimited") == 0) {
288 new_limit = RLIM_INFINITY;
289 } else if (wcscasecmp(argv[w.woptind], L"hard") == 0) {
290 new_limit = get(what, 1);
291 } else if (wcscasecmp(argv[w.woptind], L"soft") == 0) {
292 new_limit = get(what, soft);
293 } else {
294 new_limit = fish_wcstol(argv[w.woptind]);
295 if (errno) {
296 streams.err.append_format(_(L"%ls: Invalid limit '%ls'\n"), cmd, argv[w.woptind]);
297 builtin_print_error_trailer(parser, streams.err, cmd);
298 return STATUS_INVALID_ARGS;
299 }
300 new_limit *= get_multiplier(what);
301 }
302
303 return set_limit(what, hard, soft, new_limit, streams);
304 }
305