Commit | Line | Data |
---|---|---|
93665ffd | 1 | static char *sccsid = "@(#)write.c 4.6 %G%"; |
cd784246 BJ |
2 | /* |
3 | * write to another user | |
4 | */ | |
5 | ||
6 | #include <stdio.h> | |
7 | #include <sys/types.h> | |
8 | #include <sys/stat.h> | |
9 | #include <signal.h> | |
10 | #include <utmp.h> | |
11 | #include <time.h> | |
12 | ||
cf288731 BJ |
13 | #define NMAX sizeof(ubuf.ut_name) |
14 | #define LMAX sizeof(ubuf.ut_line) | |
cd784246 BJ |
15 | |
16 | char *strcat(); | |
17 | char *strcpy(); | |
18 | struct utmp ubuf; | |
19 | int signum[] = {SIGHUP, SIGINT, SIGQUIT, 0}; | |
20 | char me[10] = "???"; | |
21 | char *him; | |
22 | char *mytty; | |
23 | char histty[32]; | |
24 | char *histtya; | |
25 | char *ttyname(); | |
26 | char *rindex(); | |
27 | int logcnt; | |
28 | int eof(); | |
29 | int timout(); | |
30 | FILE *tf; | |
31 | char *getenv(); | |
32 | ||
33 | main(argc, argv) | |
cf288731 BJ |
34 | int argc; |
35 | char *argv[]; | |
cd784246 BJ |
36 | { |
37 | struct stat stbuf; | |
38 | register i; | |
39 | register FILE *uf; | |
40 | int c1, c2; | |
cf288731 | 41 | long clock = time(0); |
cd784246 BJ |
42 | struct tm *localtime(); |
43 | struct tm *localclock = localtime( &clock ); | |
44 | ||
cf288731 | 45 | if (argc < 2) { |
cd784246 BJ |
46 | printf("usage: write user [ttyname]\n"); |
47 | exit(1); | |
48 | } | |
49 | him = argv[1]; | |
cf288731 | 50 | if (argc > 2) |
cd784246 BJ |
51 | histtya = argv[2]; |
52 | if ((uf = fopen("/etc/utmp", "r")) == NULL) { | |
53 | printf("cannot open /etc/utmp\n"); | |
54 | goto cont; | |
55 | } | |
56 | mytty = ttyname(2); | |
57 | if (mytty == NULL) { | |
58 | printf("Can't find your tty\n"); | |
59 | exit(1); | |
60 | } | |
cf288731 BJ |
61 | if (stat(mytty, &stbuf) < 0) { |
62 | printf("Can't stat your tty\n"); | |
63 | exit(1); | |
b40712b7 ES |
64 | } |
65 | if ((stbuf.st_mode&02) == 0) { | |
cf288731 BJ |
66 | printf("You have write permission turned off.\n"); |
67 | exit(1); | |
b40712b7 | 68 | } |
cd784246 BJ |
69 | mytty = rindex(mytty, '/') + 1; |
70 | if (histtya) { | |
71 | strcpy(histty, "/dev/"); | |
72 | strcat(histty, histtya); | |
73 | } | |
74 | while (fread((char *)&ubuf, sizeof(ubuf), 1, uf) == 1) { | |
b85a75a1 EA |
75 | if (ubuf.ut_name[0] == '\0') |
76 | continue; | |
cd784246 | 77 | if (strcmp(ubuf.ut_line, mytty)==0) { |
cf288731 | 78 | for (i=0; i<NMAX; i++) { |
cd784246 | 79 | c1 = ubuf.ut_name[i]; |
cf288731 | 80 | if (c1 == ' ') |
cd784246 BJ |
81 | c1 = 0; |
82 | me[i] = c1; | |
cf288731 | 83 | if (c1 == 0) |
cd784246 BJ |
84 | break; |
85 | } | |
86 | } | |
cf288731 BJ |
87 | if (him[0] != '-' || him[1] != 0) |
88 | for (i=0; i<NMAX; i++) { | |
cd784246 BJ |
89 | c1 = him[i]; |
90 | c2 = ubuf.ut_name[i]; | |
cf288731 BJ |
91 | if (c1 == 0) |
92 | if (c2 == 0 || c2 == ' ') | |
cd784246 | 93 | break; |
cf288731 | 94 | if (c1 != c2) |
cd784246 BJ |
95 | goto nomat; |
96 | } | |
97 | logcnt++; | |
98 | if (histty[0]==0) { | |
99 | strcpy(histty, "/dev/"); | |
100 | strcat(histty, ubuf.ut_line); | |
101 | } | |
102 | nomat: | |
103 | ; | |
104 | } | |
105 | cont: | |
106 | if (logcnt==0 && histty[0]=='\0') { | |
107 | printf("%s not logged in.\n", him); | |
108 | exit(1); | |
109 | } | |
110 | fclose(uf); | |
111 | if (histtya==0 && logcnt > 1) { | |
112 | printf("%s logged more than once\nwriting to %s\n", him, histty+5); | |
113 | } | |
cf288731 | 114 | if (histty[0] == 0) { |
cd784246 | 115 | printf(him); |
cf288731 | 116 | if (logcnt) |
cd784246 BJ |
117 | printf(" not on that tty\n"); else |
118 | printf(" not logged in\n"); | |
119 | exit(1); | |
120 | } | |
121 | if (access(histty, 0) < 0) { | |
122 | printf("No such tty\n"); | |
123 | exit(1); | |
124 | } | |
125 | signal(SIGALRM, timout); | |
126 | alarm(5); | |
127 | if ((tf = fopen(histty, "w")) == NULL) | |
128 | goto perm; | |
129 | alarm(0); | |
130 | if (fstat(fileno(tf), &stbuf) < 0) | |
131 | goto perm; | |
132 | if ((stbuf.st_mode&02) == 0) | |
133 | goto perm; | |
134 | sigs(eof); | |
cf288731 BJ |
135 | { char hostname[32]; |
136 | gethostname(hostname, sizeof (hostname)); | |
137 | fprintf(tf, "\r\nMessage from "); | |
138 | fprintf(tf, "%s!%s on %s at %d:%02d ...\r\n\a\a\a", | |
139 | hostname, me, mytty, localclock->tm_hour, localclock->tm_min); | |
140 | } | |
cd784246 | 141 | fflush(tf); |
cf288731 | 142 | for (;;) { |
cd784246 BJ |
143 | char buf[128]; |
144 | i = read(0, buf, 128); | |
cf288731 | 145 | if (i <= 0) |
cd784246 | 146 | eof(); |
cf288731 | 147 | if (buf[0] == '!') { |
cd784246 BJ |
148 | buf[i] = 0; |
149 | ex(buf); | |
150 | continue; | |
151 | } | |
93665ffd RE |
152 | if (write(fileno(tf), buf, i) != i) { |
153 | printf("\n\7Write failed (%s logged out?)\n", him); | |
154 | exit(1); | |
155 | } | |
cf288731 BJ |
156 | if (buf[i-1] == '\n') |
157 | write(fileno(tf), "\r", 1); | |
cd784246 | 158 | } |
cd784246 BJ |
159 | perm: |
160 | printf("Permission denied\n"); | |
161 | exit(1); | |
162 | } | |
163 | ||
164 | timout() | |
165 | { | |
166 | ||
167 | printf("Timeout opening their tty\n"); | |
168 | exit(1); | |
169 | } | |
170 | ||
171 | eof() | |
172 | { | |
173 | ||
174 | fprintf(tf, "EOF\r\n"); | |
175 | exit(0); | |
176 | } | |
177 | ||
178 | ex(bp) | |
cf288731 | 179 | char *bp; |
cd784246 BJ |
180 | { |
181 | register i; | |
182 | ||
183 | sigs(SIG_IGN); | |
184 | i = fork(); | |
cf288731 | 185 | if (i < 0) { |
cd784246 BJ |
186 | printf("Try again\n"); |
187 | goto out; | |
188 | } | |
cf288731 | 189 | if (i == 0) { |
cd784246 | 190 | sigs((int (*)())0); |
cf288731 BJ |
191 | execl(getenv("SHELL") ? |
192 | getenv("SHELL") : "/bin/sh", "sh", "-c", bp+1, 0); | |
cd784246 BJ |
193 | exit(0); |
194 | } | |
cf288731 | 195 | while (wait((int *)NULL) != i) |
cd784246 BJ |
196 | ; |
197 | printf("!\n"); | |
198 | out: | |
199 | sigs(eof); | |
200 | } | |
201 | ||
202 | sigs(sig) | |
cf288731 | 203 | int (*sig)(); |
cd784246 BJ |
204 | { |
205 | register i; | |
206 | ||
cf288731 BJ |
207 | for (i=0; signum[i]; i++) |
208 | signal(signum[i], sig); | |
cd784246 | 209 | } |