Commit | Line | Data |
---|---|---|
31b42ab1 | 1 | #ifndef lint |
10e7537d | 2 | static char *sccsid = "@(#)write.c 4.13 %G%"; |
31b42ab1 | 3 | #endif |
cd784246 BJ |
4 | /* |
5 | * write to another user | |
6 | */ | |
7 | ||
8 | #include <stdio.h> | |
31b42ab1 | 9 | #include <ctype.h> |
cd784246 BJ |
10 | #include <sys/types.h> |
11 | #include <sys/stat.h> | |
12 | #include <signal.h> | |
13 | #include <utmp.h> | |
72cf2549 | 14 | #include <sys/time.h> |
cd784246 | 15 | |
cf288731 BJ |
16 | #define NMAX sizeof(ubuf.ut_name) |
17 | #define LMAX sizeof(ubuf.ut_line) | |
cd784246 BJ |
18 | |
19 | char *strcat(); | |
20 | char *strcpy(); | |
21 | struct utmp ubuf; | |
22 | int signum[] = {SIGHUP, SIGINT, SIGQUIT, 0}; | |
31b42ab1 | 23 | char me[NMAX + 1] = "???"; |
cd784246 BJ |
24 | char *him; |
25 | char *mytty; | |
26 | char histty[32]; | |
14c6ba7a | 27 | char ttybuf[32]; |
cd784246 BJ |
28 | char *histtya; |
29 | char *ttyname(); | |
30 | char *rindex(); | |
31 | int logcnt; | |
32 | int eof(); | |
33 | int timout(); | |
34 | FILE *tf; | |
35 | char *getenv(); | |
36 | ||
37 | main(argc, argv) | |
cf288731 BJ |
38 | int argc; |
39 | char *argv[]; | |
cd784246 BJ |
40 | { |
41 | struct stat stbuf; | |
42 | register i; | |
43 | register FILE *uf; | |
44 | int c1, c2; | |
cf288731 | 45 | long clock = time(0); |
25a06dbc | 46 | int suser = getuid() == 0; |
14c6ba7a | 47 | int nomesg = 0; |
cd784246 BJ |
48 | struct tm *localtime(); |
49 | struct tm *localclock = localtime( &clock ); | |
50 | ||
cf288731 | 51 | if (argc < 2) { |
31b42ab1 | 52 | fprintf(stderr, "Usage: write user [ttyname]\n"); |
cd784246 BJ |
53 | exit(1); |
54 | } | |
55 | him = argv[1]; | |
cf288731 | 56 | if (argc > 2) |
cd784246 BJ |
57 | histtya = argv[2]; |
58 | if ((uf = fopen("/etc/utmp", "r")) == NULL) { | |
31b42ab1 | 59 | perror("write: Can't open /etc/utmp"); |
c7616a71 MK |
60 | if (histtya == 0) |
61 | exit(10); | |
cd784246 BJ |
62 | goto cont; |
63 | } | |
64 | mytty = ttyname(2); | |
65 | if (mytty == NULL) { | |
31b42ab1 | 66 | fprintf(stderr, "write: Can't find your tty\n"); |
cd784246 BJ |
67 | exit(1); |
68 | } | |
cf288731 | 69 | if (stat(mytty, &stbuf) < 0) { |
31b42ab1 | 70 | perror("write: Can't stat your tty"); |
cf288731 | 71 | exit(1); |
b40712b7 | 72 | } |
10e7537d | 73 | if ((stbuf.st_mode&020) == 0) { |
31b42ab1 S |
74 | fprintf(stderr, |
75 | "write: You have write permission turned off\n"); | |
14c6ba7a MK |
76 | if (!suser) |
77 | exit(1); | |
b40712b7 | 78 | } |
cd784246 BJ |
79 | mytty = rindex(mytty, '/') + 1; |
80 | if (histtya) { | |
81 | strcpy(histty, "/dev/"); | |
82 | strcat(histty, histtya); | |
83 | } | |
84 | while (fread((char *)&ubuf, sizeof(ubuf), 1, uf) == 1) { | |
b85a75a1 EA |
85 | if (ubuf.ut_name[0] == '\0') |
86 | continue; | |
cd784246 | 87 | if (strcmp(ubuf.ut_line, mytty)==0) { |
cf288731 | 88 | for (i=0; i<NMAX; i++) { |
cd784246 | 89 | c1 = ubuf.ut_name[i]; |
cf288731 | 90 | if (c1 == ' ') |
cd784246 BJ |
91 | c1 = 0; |
92 | me[i] = c1; | |
cf288731 | 93 | if (c1 == 0) |
cd784246 BJ |
94 | break; |
95 | } | |
96 | } | |
31b42ab1 S |
97 | if (him[0] == '-' && him[1] == 0) |
98 | goto nomat; | |
cf288731 | 99 | for (i=0; i<NMAX; i++) { |
cd784246 BJ |
100 | c1 = him[i]; |
101 | c2 = ubuf.ut_name[i]; | |
cf288731 BJ |
102 | if (c1 == 0) |
103 | if (c2 == 0 || c2 == ' ') | |
cd784246 | 104 | break; |
cf288731 | 105 | if (c1 != c2) |
cd784246 BJ |
106 | goto nomat; |
107 | } | |
14c6ba7a MK |
108 | if (histtya && strncmp(histtya, ubuf.ut_line, |
109 | sizeof(ubuf.ut_line))) | |
110 | continue; | |
cd784246 | 111 | logcnt++; |
14c6ba7a MK |
112 | if (histty[0]==0 || nomesg && histtya == 0) { |
113 | strcpy(ttybuf, "/dev/"); | |
114 | strcat(ttybuf, ubuf.ut_line); | |
115 | if (histty[0]==0) | |
116 | strcpy(histty, ttybuf); | |
117 | if (access(ttybuf, 0) < 0 || stat(ttybuf, &stbuf) < 0 || | |
10e7537d | 118 | (stbuf.st_mode&020) == 0) |
14c6ba7a MK |
119 | nomesg++; |
120 | else { | |
121 | strcpy(histty, ttybuf); | |
122 | nomesg = 0; | |
123 | } | |
cd784246 BJ |
124 | } |
125 | nomat: | |
126 | ; | |
127 | } | |
c7616a71 | 128 | fclose(uf); |
14c6ba7a | 129 | if (logcnt==0) { |
c7616a71 MK |
130 | fprintf(stderr, "write: %s not logged in%s\n", him, |
131 | histtya ? " on that tty" : ""); | |
cd784246 BJ |
132 | exit(1); |
133 | } | |
cd784246 | 134 | if (histtya==0 && logcnt > 1) { |
31b42ab1 S |
135 | fprintf(stderr, |
136 | "write: %s logged in more than once ... writing to %s\n", | |
137 | him, histty+5); | |
cd784246 | 138 | } |
c7616a71 | 139 | cont: |
cd784246 | 140 | if (access(histty, 0) < 0) { |
31b42ab1 | 141 | fprintf(stderr, "write: No such tty\n"); |
cd784246 BJ |
142 | exit(1); |
143 | } | |
144 | signal(SIGALRM, timout); | |
145 | alarm(5); | |
14c6ba7a MK |
146 | if ((tf = fopen(histty, "w")) == NULL) { |
147 | fprintf(stderr, "write: Permission denied\n"); | |
148 | exit(1); | |
149 | } | |
cd784246 | 150 | alarm(0); |
cd784246 | 151 | sigs(eof); |
cf288731 BJ |
152 | { char hostname[32]; |
153 | gethostname(hostname, sizeof (hostname)); | |
31b42ab1 S |
154 | fprintf(tf, |
155 | "\r\nMessage from %s@%s on %s at %d:%02d ...\r\n\007\007\007", | |
156 | me, hostname, mytty, localclock->tm_hour, localclock->tm_min); | |
cd784246 | 157 | fflush(tf); |
31b42ab1 | 158 | } |
cf288731 | 159 | for (;;) { |
31b42ab1 S |
160 | char buf[BUFSIZ]; |
161 | register char *bp; | |
162 | i = read(0, buf, sizeof buf); | |
cf288731 | 163 | if (i <= 0) |
cd784246 | 164 | eof(); |
cf288731 | 165 | if (buf[0] == '!') { |
cd784246 BJ |
166 | buf[i] = 0; |
167 | ex(buf); | |
168 | continue; | |
169 | } | |
31b42ab1 S |
170 | for (bp = buf; --i >= 0; bp++) { |
171 | if (*bp == '\n') | |
172 | putc('\r', tf); | |
173 | ||
174 | if (!isascii(*bp)) { | |
175 | putc('M', tf); | |
176 | putc('-', tf); | |
177 | *bp = toascii(*bp); | |
178 | } | |
179 | ||
180 | if (isprint(*bp) || | |
181 | *bp == ' ' || *bp == '\t' || *bp == '\n') { | |
182 | putc(*bp, tf); | |
183 | } else { | |
184 | putc('^', tf); | |
185 | putc(*bp ^ 0100, tf); | |
186 | } | |
187 | ||
188 | if (*bp == '\n') | |
189 | fflush(tf); | |
190 | ||
191 | if (ferror(tf) || feof(tf)) { | |
192 | printf("\n\007Write failed (%s logged out?)\n", | |
193 | him); | |
194 | exit(1); | |
195 | } | |
93665ffd | 196 | } |
cd784246 | 197 | } |
cd784246 BJ |
198 | } |
199 | ||
200 | timout() | |
201 | { | |
202 | ||
31b42ab1 | 203 | fprintf(stderr, "write: Timeout opening their tty\n"); |
cd784246 BJ |
204 | exit(1); |
205 | } | |
206 | ||
207 | eof() | |
208 | { | |
209 | ||
210 | fprintf(tf, "EOF\r\n"); | |
211 | exit(0); | |
212 | } | |
213 | ||
214 | ex(bp) | |
cf288731 | 215 | char *bp; |
cd784246 BJ |
216 | { |
217 | register i; | |
218 | ||
219 | sigs(SIG_IGN); | |
220 | i = fork(); | |
cf288731 | 221 | if (i < 0) { |
cd784246 BJ |
222 | printf("Try again\n"); |
223 | goto out; | |
224 | } | |
cf288731 | 225 | if (i == 0) { |
10e7537d KM |
226 | fclose(tf); /* Close his terminal */ |
227 | setgid(getgid()); /* Give up effective group privs */ | |
cd784246 | 228 | sigs((int (*)())0); |
cf288731 BJ |
229 | execl(getenv("SHELL") ? |
230 | getenv("SHELL") : "/bin/sh", "sh", "-c", bp+1, 0); | |
cd784246 BJ |
231 | exit(0); |
232 | } | |
cf288731 | 233 | while (wait((int *)NULL) != i) |
cd784246 BJ |
234 | ; |
235 | printf("!\n"); | |
236 | out: | |
237 | sigs(eof); | |
238 | } | |
239 | ||
240 | sigs(sig) | |
cf288731 | 241 | int (*sig)(); |
cd784246 BJ |
242 | { |
243 | register i; | |
244 | ||
cf288731 BJ |
245 | for (i=0; signum[i]; i++) |
246 | signal(signum[i], sig); | |
cd784246 | 247 | } |