Add udpsysrqd program
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@@ -0,0 +1,22 @@ | ||
1 | +INSTALL := install | |
2 | +USRBINDIR := /usr/bin | |
3 | +USRDOCDIR := /usr/share/doc | |
4 | +ifndef CFLAGS | |
5 | +CFLAGS := -Wall -O2 -g -D_FORTIFY_SOURCE=2 | |
6 | +endif | |
7 | + | |
8 | +all: udpsysrqd | |
9 | + | |
10 | +udpsysrqd: udpsysrqd.c | |
11 | + $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o udpsysrqd udpsysrqd.c | |
12 | + | |
13 | +install: all | |
14 | + mkdir -p -m 0755 $(INSTALLDIR)$(USRBINDIR) | |
15 | + $(INSTALL) -m 0755 udpsysrqd $(INSTALLDIR)$(USRBINDIR) | |
16 | + mkdir -p -m 0755 $(INSTALLDIR)$(USRDOCDIR)/udpsysrqd/ | |
17 | + $(INSTALL) -m 0644 README COPYING udpsysrqd.conf $(INSTALLDIR)$(USRDOCDIR)/udpsysrqd/ | |
18 | + | |
19 | +clean: | |
20 | + rm -f -- udpsysrqd | |
21 | + | |
22 | +.PHONY: clean install |
@@ -0,0 +1,63 @@ | ||
1 | +About this package: | |
2 | + | |
3 | + When troubleshooting system freeze problems, obtaining SysRq messages | |
4 | + is commonly used. However, it is impossible for administrators to | |
5 | + use the SysRq keys if he/she is not seated in front of the console. | |
6 | + | |
7 | + This package contains a utility for triggering SysRq via UDP packets | |
8 | + based on an assumption that the kernel's scheduling functionality is | |
9 | + alive. | |
10 | + | |
11 | + This package is released under the GPLv2. | |
12 | + | |
13 | +How to use this utility: | |
14 | + | |
15 | + There are 4 entries which are given via a configuration file | |
16 | + specified at command line. Included udpsysrqd.conf is an example. | |
17 | + | |
18 | + listen_ip $listen_ip | |
19 | + | |
20 | + $listen_ip specifies the local IPv4 or IPv6 address to listen to. | |
21 | + Default value is :: if IPv6 is available, 0.0.0.0 otherwise. | |
22 | + | |
23 | + listen_port $listen_port | |
24 | + | |
25 | + $listen_port specifies the local port number to listen to. | |
26 | + Default value is 0. | |
27 | + | |
28 | + trap $sysrq $magic | |
29 | + | |
30 | + $sysrq is a SysRq command (e.g. h t w, or combination of them). | |
31 | + | |
32 | + $magic is a string which writes $sysrq to /proc/sysrq-trigger | |
33 | + when a UDP packet containing this string was received. | |
34 | + Since $magic can contain only bytes in 0x21-0x5B,0x5D-0x7E range, | |
35 | + please note that packets containing end of line bytes won't match. | |
36 | + | |
37 | + Although $magic acts like a password which prevents unwanted sources | |
38 | + from triggering $sysrq , you must ensure security by other means | |
39 | + because $magic is sent as a plain clear text and is very vulnerable | |
40 | + to attacks such as eavesdropping and brute force. | |
41 | + | |
42 | + This entry is optional if "default " entry is specified. | |
43 | + You can specify this entry for up to 256 times. | |
44 | + | |
45 | + default $timeout1 [ $sysrq1 [ $timeout2 [ $sysrq2 [ ... ]]]] | |
46 | + | |
47 | + $timeoutX is a timeout in milliseconds waiting for a UDP packet | |
48 | + to arrive. A negative value (e.g. -1) means no timeout. | |
49 | + | |
50 | + $sysrqX is a SysRq command which will be written to | |
51 | + /proc/sysrq-trigger when no packets are received within | |
52 | + $timeoutX timeout. | |
53 | + | |
54 | + Upon $timeout1, $sysrq1 is written and new timeout becomes $timeout2. | |
55 | + Upon $timeout2, $sysrq2 is written and new timeout becomes $timeout3. | |
56 | + Upon $timeout3, $sysrq3 is written and new timeout becomes $timeout4. | |
57 | + | |
58 | + -1 is implicitly appended to the tail of this entry which means that | |
59 | + no more actions will be taken automatically. | |
60 | + | |
61 | + If a UDP packet arrives, new timeout becomes $timeout1. | |
62 | + | |
63 | + This entry is optional if "trap " entry is specified. |
@@ -0,0 +1,328 @@ | ||
1 | +/* | |
2 | + * Simple SysRq daemon - A utility for triggering SysRq via UDP packets. | |
3 | + * | |
4 | + * Written by Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | |
5 | + * | |
6 | + * Distributed under GPL v2. | |
7 | + */ | |
8 | +#include <stdio.h> | |
9 | +#include <string.h> | |
10 | +#include <stdlib.h> | |
11 | +#include <unistd.h> | |
12 | +#include <poll.h> | |
13 | +#include <sys/types.h> | |
14 | +#include <sys/stat.h> | |
15 | +#include <fcntl.h> | |
16 | +#include <sys/socket.h> | |
17 | +#include <arpa/inet.h> | |
18 | +#include <stdarg.h> | |
19 | +#include <errno.h> | |
20 | +#include <sys/mman.h> | |
21 | + | |
22 | +/* Structure for holding IPv4 or IPv6 address. */ | |
23 | +union ipaddr { | |
24 | + struct sockaddr_in ip4; | |
25 | + struct sockaddr_in6 ip6; | |
26 | +}; | |
27 | + | |
28 | +/* Structure for holding on-demand SysRq action list. */ | |
29 | +#define MAX_TRAPS 256 | |
30 | +static struct command { | |
31 | + const char *magic; | |
32 | + const char *command; | |
33 | + int magic_len; | |
34 | + int command_len; | |
35 | +} traps[MAX_TRAPS]; | |
36 | + | |
37 | +/* Default actions with timeouts. */ | |
38 | +static char *default_action = NULL; | |
39 | +/* Number of on-demand actions defined. */ | |
40 | +static int num_traps = 0; | |
41 | +/* File descriptor for /proc/sysrq-trigger . */ | |
42 | +static int sysrq_fd = EOF; | |
43 | +/* Receiver socket's file descriptor. */ | |
44 | +static int socket_fd = EOF; | |
45 | + | |
46 | +/** | |
47 | + * die - Print error and exit. | |
48 | + * | |
49 | + * @fmt: Format string, followed by arguments. | |
50 | + * | |
51 | + * This function does not return. | |
52 | + */ | |
53 | +static void die(const char *fmt, ...) __attribute__((format(printf, 1, 2))); | |
54 | +static void die(const char *fmt, ...) | |
55 | +{ | |
56 | + const int err = errno; | |
57 | + va_list args; | |
58 | + va_start(args, fmt); | |
59 | + vfprintf(stderr, fmt, args); | |
60 | + va_end(args); | |
61 | + fprintf(stderr, " : %s(%d)\n", strerror(err), err); | |
62 | + exit(1); | |
63 | +} | |
64 | + | |
65 | +/** | |
66 | + * help - Print help and exit. | |
67 | + * | |
68 | + * @fmt: Format string, followed by arguments. | |
69 | + * | |
70 | + * This function does not return. | |
71 | + */ | |
72 | +static void help(const char *fmt, ...) __attribute__((format(printf, 1, 2))); | |
73 | +static void help(const char *fmt, ...) | |
74 | +{ | |
75 | + va_list args; | |
76 | + fprintf(stderr, "Simple SysRq daemon\n\nError: "); | |
77 | + va_start(args, fmt); | |
78 | + vfprintf(stderr, fmt, args); | |
79 | + va_end(args); | |
80 | + fprintf(stderr, "\n\nPlease see the README file.\n"); | |
81 | + exit(1); | |
82 | +} | |
83 | + | |
84 | +/** | |
85 | + * get_addr - Get string representation of IP address. | |
86 | + * | |
87 | + * @ipv6: True if @addr contains an IPv6 address, false otheriwse. | |
88 | + * @addr: Pointer to "union ipaddr". | |
89 | + * | |
90 | + * Returns static buffer to IP string. | |
91 | + */ | |
92 | +static const char *get_addr(_Bool ipv6, const union ipaddr *addr) | |
93 | +{ | |
94 | + static char buf[40]; | |
95 | + memset(buf, 0, sizeof(buf)); | |
96 | + if (ipv6) | |
97 | + inet_ntop(AF_INET6, &addr->ip6.sin6_addr, buf, sizeof(buf)); | |
98 | + else | |
99 | + inet_ntop(AF_INET, &addr->ip4.sin_addr, buf, sizeof(buf)); | |
100 | + return buf; | |
101 | +} | |
102 | + | |
103 | +/** | |
104 | + * normalize_line - Format string. | |
105 | + * | |
106 | + * @buffer: The line to normalize. | |
107 | + * | |
108 | + * Returns nothing. | |
109 | + * | |
110 | + * Leading and trailing whitespaces are removed. | |
111 | + * Multiple whitespaces are packed into single space. | |
112 | + */ | |
113 | +static void normalize_line(char *buffer) | |
114 | +{ | |
115 | + unsigned char *sp = (unsigned char *) buffer; | |
116 | + unsigned char *dp = (unsigned char *) buffer; | |
117 | + _Bool first = 1; | |
118 | + while (*sp && (*sp <= ' ' || 127 <= *sp)) | |
119 | + sp++; | |
120 | + while (*sp) { | |
121 | + if (!first) | |
122 | + *dp++ = ' '; | |
123 | + first = 0; | |
124 | + while (' ' < *sp && *sp < 127) | |
125 | + *dp++ = *sp++; | |
126 | + while (*sp && (*sp <= ' ' || 127 <= *sp)) | |
127 | + sp++; | |
128 | + } | |
129 | + *dp = '\0'; | |
130 | +} | |
131 | + | |
132 | +/** | |
133 | + * my_strdup - strdup() with error checking. | |
134 | + * | |
135 | + * @str: The string to duplicate. | |
136 | + * | |
137 | + * Returns a duplicated string on success, abort otherwise. | |
138 | + */ | |
139 | +static char *my_strdup(const char *str) | |
140 | +{ | |
141 | + char *cp = strdup(str); | |
142 | + if (!cp) { | |
143 | + fprintf(stderr, "Out of memory.\n"); | |
144 | + exit(1); | |
145 | + } | |
146 | + return cp; | |
147 | +} | |
148 | + | |
149 | +/** | |
150 | + * do_init - Initialization function. | |
151 | + * | |
152 | + * @argc: Number of arguments. | |
153 | + * @argv: Arguments. | |
154 | + * | |
155 | + * Returns nothing. | |
156 | + */ | |
157 | +static void do_init(int argc, char *argv[]) | |
158 | +{ | |
159 | + union ipaddr addr = { }; | |
160 | + socklen_t size; | |
161 | + int fd = EOF; | |
162 | + _Bool ipv6 = 1; | |
163 | + const char *ip = NULL; | |
164 | + unsigned short port = 0; | |
165 | + char line[1024]; | |
166 | + int lineno = 0; | |
167 | + FILE *fp; | |
168 | + if (argc != 2) | |
169 | + help("Please specify a configuration file."); | |
170 | + fp = fopen(argv[1], "r"); | |
171 | + if (!fp) | |
172 | + help("Can't open %s for reading.", argv[1]); | |
173 | + memset(traps, 0, sizeof(traps)); | |
174 | + while (memset(line, 0, sizeof(line)), lineno++, | |
175 | + fgets(line, sizeof(line) - 1, fp)) { | |
176 | + char *cp = strchr(line, '\n'); | |
177 | + if (!cp) | |
178 | + help("Line %u: Too long or truncated.", lineno); | |
179 | + cp = strchr(line, '#'); | |
180 | + if (cp) | |
181 | + *cp = '\0'; | |
182 | + normalize_line(line); | |
183 | + if (!*line) | |
184 | + continue; | |
185 | + if (!default_action && !strncmp(line, "default ", 8)) | |
186 | + default_action = my_strdup(line + 8); | |
187 | + else if (!ip && !strncmp(line, "listen_ip ", 10)) | |
188 | + ip = my_strdup(line + 10); | |
189 | + else if (!port && !strncmp(line, "listen_port ", 12)) | |
190 | + port = atoi(line + 12); | |
191 | + else if (!strncmp(line, "trap ", 5)) { | |
192 | + int i; | |
193 | + cp = strchr(line + 5, ' '); | |
194 | + if (!cp) | |
195 | + help("Line %u: A \"trap \" entry needs " | |
196 | + "$sysrq and $magic arguments.", lineno); | |
197 | + *cp++ = '\0'; | |
198 | + for (i = 0; cp[i]; i++) { | |
199 | + const char c = cp[i]; | |
200 | + if (c > 0x20 && c < 0x7F && c != 0x5C) | |
201 | + continue; | |
202 | + help("Line %u: '%c' is an invalid character.", | |
203 | + lineno, c); | |
204 | + } | |
205 | + i = num_traps++; | |
206 | + if (i >= MAX_TRAPS) | |
207 | + help("Line %u: Too many \"trap \" entries.", | |
208 | + lineno); | |
209 | + traps[i].magic = my_strdup(cp); | |
210 | + traps[i].magic_len = strlen(traps[i].magic); | |
211 | + traps[i].command = my_strdup(line + 5); | |
212 | + traps[i].command_len = strlen(traps[i].command); | |
213 | + } else { | |
214 | + help("Line %u: Invalid line.", lineno); | |
215 | + } | |
216 | + } | |
217 | + fclose(fp); | |
218 | + if (!default_action && !num_traps) | |
219 | + help("Neither \"default \" entry nor \"trap \" entry is given."); | |
220 | + if (!default_action) | |
221 | + default_action = my_strdup(""); | |
222 | + /* Open /proc/sysrq-trigger for writing. */ | |
223 | + sysrq_fd = open("/proc/sysrq-trigger", O_WRONLY); | |
224 | + if (sysrq_fd == EOF) | |
225 | + die("Can't open /proc/sysrq-trigger"); | |
226 | + /* Create the listener socket and configure it. */ | |
227 | + if (!ip || inet_pton(AF_INET, ip, &addr.ip4.sin_addr) != 1) { | |
228 | + fd = socket(PF_INET6, SOCK_DGRAM, 0); | |
229 | + /* | |
230 | + * Give up if IPv6 address was requested but IPv6 socket is not | |
231 | + * available. | |
232 | + */ | |
233 | + if (fd == EOF && ip) | |
234 | + die("Can't create IPv6 socket"); | |
235 | + } | |
236 | + if (fd == EOF) { | |
237 | + fd = socket(PF_INET, SOCK_DGRAM, 0); | |
238 | + /* Give up if IPv4 socket is not available. */ | |
239 | + if (fd == EOF) | |
240 | + die("Can't create IPv4 socket"); | |
241 | + ipv6 = 0; | |
242 | + } | |
243 | + socket_fd = fd; | |
244 | + if (ipv6) { | |
245 | + addr.ip6.sin6_family = AF_INET6; | |
246 | + addr.ip6.sin6_port = htons(port); | |
247 | + if (!ip) | |
248 | + addr.ip6.sin6_addr = in6addr_any; | |
249 | + else if (inet_pton(AF_INET6, ip, &addr.ip6.sin6_addr) != 1) { | |
250 | + fprintf(stderr, "%s is an invalid IPv6 address\n", ip); | |
251 | + exit(1); | |
252 | + } | |
253 | + } else { | |
254 | + addr.ip4.sin_family = AF_INET; | |
255 | + addr.ip4.sin_port = htons(port); | |
256 | + if (!ip) | |
257 | + addr.ip4.sin_addr.s_addr = htonl(INADDR_ANY); | |
258 | + } | |
259 | + ip = get_addr(ipv6, &addr); | |
260 | + if (ipv6) | |
261 | + port = ntohs(addr.ip6.sin6_port); | |
262 | + else | |
263 | + port = ntohs(addr.ip4.sin_port); | |
264 | + size = ipv6 ? sizeof(addr.ip6) : sizeof(addr.ip4); | |
265 | + if (bind(fd, (struct sockaddr *) &addr, size)) | |
266 | + die("Can't bind to ip=%s port=%u", ip, port); | |
267 | + else if (getsockname(fd, (struct sockaddr *) &addr, &size)) | |
268 | + die("Can't get bound address"); | |
269 | + ip = get_addr(ipv6, &addr); | |
270 | + if (ipv6) | |
271 | + port = ntohs(addr.ip6.sin6_port); | |
272 | + else | |
273 | + port = ntohs(addr.ip4.sin_port); | |
274 | + printf("Listening at ip=%s port=%u\n", ip, port); | |
275 | + /* Close unused file descriptors. */ | |
276 | + for (fd = 0; fd < 1024; fd++) | |
277 | + if (fd != sysrq_fd && fd != socket_fd) | |
278 | + close(fd); | |
279 | + /* Try to avoid page faults, but not required to be perfect. */ | |
280 | + mlockall(MCL_CURRENT); | |
281 | +} | |
282 | + | |
283 | +int main(int argc, char *argv[]) | |
284 | +{ | |
285 | + char *pos; | |
286 | + do_init(argc, argv); | |
287 | + pos = default_action; | |
288 | + while (1) { | |
289 | + int ret_ignored = 0; | |
290 | + static char buffer[1024] = { }; | |
291 | + struct pollfd pfd = { socket_fd, POLLIN, 0 }; | |
292 | + int i; | |
293 | + int len = strtol(pos, &pos, 10); | |
294 | + if (*pos == ' ') | |
295 | + pos++; | |
296 | + else | |
297 | + len = -1; /* Negative value means no timeout. */ | |
298 | + switch (poll(&pfd, 1, len)) { | |
299 | + case 0: /* No packet within timeout. */ | |
300 | + /* Let's start/continue default sysrq action. */ | |
301 | + while (*pos && *pos != ' ') | |
302 | + ret_ignored += write(sysrq_fd, pos++, 1); | |
303 | + continue; | |
304 | + case EOF: /* poll() failed for some reason. */ | |
305 | + /* Have a nap and restart the default action. */ | |
306 | + sleep(1); | |
307 | + pos = default_action; | |
308 | + continue; | |
309 | + } | |
310 | + /* poll() says that a packet arrived. */ | |
311 | + len = recv(socket_fd, buffer, sizeof(buffer), MSG_DONTWAIT); | |
312 | + /* Let's do on-demand sysrq if the packet contains magic. */ | |
313 | + for (i = 0; i < num_traps; i++) { | |
314 | + const char *cp; | |
315 | + if (traps[i].magic_len != len || | |
316 | + memcmp(traps[i].magic, buffer, len)) | |
317 | + continue; | |
318 | + cp = traps[i].command; | |
319 | + len = traps[i].command_len; | |
320 | + for (i = 0; i < len; i++) | |
321 | + ret_ignored += write(sysrq_fd, &cp[i], 1); | |
322 | + break; | |
323 | + } | |
324 | + /* Restart the default action. */ | |
325 | + pos = default_action; | |
326 | + } | |
327 | + return 0; | |
328 | +} |
@@ -0,0 +1,43 @@ | ||
1 | +Summary: A utility for triggering SysRq via UDP packets. | |
2 | +Name: udpsysrqd | |
3 | +Version: 1.0 | |
4 | +Release: 1 | |
5 | +License: GPLv2 | |
6 | +Group: Applications/System | |
7 | +ExclusiveOS: Linux | |
8 | +Autoreqprov: no | |
9 | +Buildroot: %{_tmppath}/%{name}-%{version}-%{release}-buildroot | |
10 | +Conflicts: udpsysrqd < 1.0-1 | |
11 | + | |
12 | +Source0: udpsysrqd.tar.gz | |
13 | + | |
14 | +%description | |
15 | +This package contains a utility for triggering SysRq via UDP packets. | |
16 | + | |
17 | +%prep | |
18 | + | |
19 | +%setup -q -n udpsysrqd | |
20 | + | |
21 | +%build | |
22 | + | |
23 | +make CFLAGS="-Wall $RPM_OPT_FLAGS" | |
24 | + | |
25 | +%install | |
26 | + | |
27 | +rm -rf $RPM_BUILD_ROOT | |
28 | +make INSTALLDIR=$RPM_BUILD_ROOT install | |
29 | + | |
30 | +%clean | |
31 | + | |
32 | +rm -rf $RPM_BUILD_ROOT | |
33 | + | |
34 | +%files | |
35 | +%defattr(-,root,root) | |
36 | +/usr/bin/udpsysrqd | |
37 | +%doc /usr/share/doc/udpsysrqd/README | |
38 | +%doc /usr/share/doc/udpsysrqd/COPYING | |
39 | +%doc /usr/share/doc/udpsysrqd/udpsysrqd.conf | |
40 | + | |
41 | +%changelog | |
42 | +* Thu Sep 13 2018 1.0-1 | |
43 | +- Initial packaging. |