local version
[unix-history] / usr / src / usr.bin / write / write.c
CommitLineData
b40712b7 1static char *sccsid = "@(#)write.c 4.3 (Berkeley) %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
13#define NMAX sizeof(ubuf.ut_name)
14#define LMAX sizeof(ubuf.ut_line)
15
16char *strcat();
17char *strcpy();
18struct utmp ubuf;
19int signum[] = {SIGHUP, SIGINT, SIGQUIT, 0};
20char me[10] = "???";
21char *him;
22char *mytty;
23char histty[32];
24char *histtya;
25char *ttyname();
26char *rindex();
27int logcnt;
28int eof();
29int timout();
30FILE *tf;
31char *getenv();
32
33main(argc, argv)
34char *argv[];
35{
36 struct stat stbuf;
37 register i;
38 register FILE *uf;
39 int c1, c2;
40 long clock = time( 0 );
41 struct tm *localtime();
42 struct tm *localclock = localtime( &clock );
43
44 if(argc < 2) {
45 printf("usage: write user [ttyname]\n");
46 exit(1);
47 }
48 him = argv[1];
49 if(argc > 2)
50 histtya = argv[2];
51 if ((uf = fopen("/etc/utmp", "r")) == NULL) {
52 printf("cannot open /etc/utmp\n");
53 goto cont;
54 }
55 mytty = ttyname(2);
56 if (mytty == NULL) {
57 printf("Can't find your tty\n");
58 exit(1);
59 }
b40712b7
ES
60 if (stat (mytty, &stbuf) < 0) {
61 printf ("Can't stat your tty\n");
62 exit (1);
63 }
64 if ((stbuf.st_mode&02) == 0) {
65 printf ("You have write permission turned off.\n");
66 exit (1);
67 }
cd784246
BJ
68 mytty = rindex(mytty, '/') + 1;
69 if (histtya) {
70 strcpy(histty, "/dev/");
71 strcat(histty, histtya);
72 }
73 while (fread((char *)&ubuf, sizeof(ubuf), 1, uf) == 1) {
b85a75a1
EA
74 if (ubuf.ut_name[0] == '\0')
75 continue;
cd784246
BJ
76 if (strcmp(ubuf.ut_line, mytty)==0) {
77 for(i=0; i<NMAX; i++) {
78 c1 = ubuf.ut_name[i];
79 if(c1 == ' ')
80 c1 = 0;
81 me[i] = c1;
82 if(c1 == 0)
83 break;
84 }
85 }
86 if(him[0] != '-' || him[1] != 0)
87 for(i=0; i<NMAX; i++) {
88 c1 = him[i];
89 c2 = ubuf.ut_name[i];
90 if(c1 == 0)
91 if(c2 == 0 || c2 == ' ')
92 break;
93 if(c1 != c2)
94 goto nomat;
95 }
96 logcnt++;
97 if (histty[0]==0) {
98 strcpy(histty, "/dev/");
99 strcat(histty, ubuf.ut_line);
100 }
101 nomat:
102 ;
103 }
104cont:
105 if (logcnt==0 && histty[0]=='\0') {
106 printf("%s not logged in.\n", him);
107 exit(1);
108 }
109 fclose(uf);
110 if (histtya==0 && logcnt > 1) {
111 printf("%s logged more than once\nwriting to %s\n", him, histty+5);
112 }
113 if(histty[0] == 0) {
114 printf(him);
115 if(logcnt)
116 printf(" not on that tty\n"); else
117 printf(" not logged in\n");
118 exit(1);
119 }
120 if (access(histty, 0) < 0) {
121 printf("No such tty\n");
122 exit(1);
123 }
124 signal(SIGALRM, timout);
125 alarm(5);
126 if ((tf = fopen(histty, "w")) == NULL)
127 goto perm;
128 alarm(0);
129 if (fstat(fileno(tf), &stbuf) < 0)
130 goto perm;
131 if ((stbuf.st_mode&02) == 0)
132 goto perm;
133 sigs(eof);
134 fprintf(tf, "\r\nMessage from ");
135#ifdef interdata
136 fprintf(tf, "(Interdata) " );
137#endif
138 fprintf(tf, "%s on %s at %d:%02d ...\r\n\a\a\a"
139 , me, mytty , localclock -> tm_hour , localclock -> tm_min );
140 fflush(tf);
141 for(;;) {
142 char buf[128];
143 i = read(0, buf, 128);
144 if(i <= 0)
145 eof();
146 if(buf[0] == '!') {
147 buf[i] = 0;
148 ex(buf);
149 continue;
150 }
151 write(fileno(tf), buf, i);
152 if ( buf[ i - 1 ] == '\n' )
153 write( fileno( tf ) , "\r" , 1 );
154 }
155
156perm:
157 printf("Permission denied\n");
158 exit(1);
159}
160
161timout()
162{
163
164 printf("Timeout opening their tty\n");
165 exit(1);
166}
167
168eof()
169{
170
171 fprintf(tf, "EOF\r\n");
172 exit(0);
173}
174
175ex(bp)
176char *bp;
177{
178 register i;
179
180 sigs(SIG_IGN);
181 i = fork();
182 if(i < 0) {
183 printf("Try again\n");
184 goto out;
185 }
186 if(i == 0) {
187 sigs((int (*)())0);
188 execl(getenv("SHELL") ? getenv("SHELL") : "/bin/sh", "sh", "-c", bp+1, 0);
189 exit(0);
190 }
191 while(wait((int *)NULL) != i)
192 ;
193 printf("!\n");
194out:
195 sigs(eof);
196}
197
198sigs(sig)
199int (*sig)();
200{
201 register i;
202
203 for(i=0;signum[i];i++)
204 signal(signum[i],sig);
205}