Commit | Line | Data |
---|---|---|
7ce72032 IJ |
1 | /* |
2 | * usage: | |
3 | * .../summon <real-summoner> <calling-nick> <calling-path> <channel> | |
4 | */ | |
5 | ||
6 | #include <stdio.h> | |
7 | #include <stdlib.h> | |
8 | #include <unistd.h> | |
9 | #include <ctype.h> | |
10 | #include <errno.h> | |
11 | #include <string.h> | |
12 | ||
13 | #include <utmp.h> | |
14 | #include <sys/types.h> | |
15 | #include <sys/stat.h> | |
16 | #include <fcntl.h> | |
17 | ||
18 | static void check(const char *string, const char *what, int maxlen) { | |
19 | int c; | |
20 | ||
21 | if (strlen(string) > maxlen) { fprintf(stderr,"%s too long\n",what); exit(8); } | |
22 | while ((c= *string++)) { | |
23 | if (isspace((unsigned char)c) || !isprint((unsigned char)c)) | |
24 | { fprintf(stderr,"bad char in %s\n",what); exit(8); } | |
25 | } | |
26 | } | |
27 | ||
28 | static void die(const char *msg) { | |
29 | fprintf(stderr,"%s\n",msg); exit(8); | |
30 | } | |
31 | ||
32 | static void problem(const char *msg) { | |
33 | printf("problem %s\n",msg); | |
34 | exit(0); | |
35 | } | |
36 | ||
37 | enum howbad { hb_notlogon, hb_noterminal, hb_nomessages, hb_ok }; | |
38 | static enum howbad closest= hb_notlogon; | |
39 | ||
40 | static time_t best_idle; | |
41 | static char best_line[UT_LINESIZE+1]; | |
42 | ||
43 | static void thisis(enum howbad hb) { | |
44 | if (hb > closest) closest= hb; | |
45 | } | |
46 | ||
47 | int main(int argc, const char *const *argv) { | |
48 | struct utmp *ue; | |
49 | const char *myself; | |
50 | struct stat stab; | |
51 | int fd; | |
52 | char idlebuf[20]; | |
53 | ||
54 | if (argc != 5) die("bad usage"); | |
55 | ||
56 | myself= getenv("USER"); | |
57 | if (!myself) die("USER not set"); | |
58 | if (strlen(myself) > UT_NAMESIZE) die("own username too long"); | |
59 | ||
60 | check(argv[2],"nick",20); | |
61 | check(argv[3],"path",60); | |
62 | check(argv[4],"channel",20); | |
63 | ||
64 | if (chdir("/dev")) { perror("chdir /dev"); exit(8); } | |
65 | ||
66 | while ((errno=0, ue= getutent())) { | |
67 | if (ue->ut_type != USER_PROCESS) continue; | |
68 | if (strncmp(ue->ut_user,myself,UT_NAMESIZE)) continue; | |
69 | if (!ue->ut_line[0]) { thisis(hb_noterminal); continue; } | |
70 | ue->ut_line[UT_LINESIZE]= 0; /* overflows into next field :-/ */ | |
71 | if (stat(ue->ut_line,&stab)) { | |
72 | printf("warning could not stat %s: %s\n",ue->ut_line,strerror(errno)); | |
73 | thisis(hb_noterminal); continue; | |
74 | } | |
75 | if (!(stab.st_mode & S_IWGRP)) { thisis(hb_nomessages); continue; } | |
76 | closest= hb_ok; | |
77 | if (closest == hb_ok && stab.st_atime <= best_idle) continue; | |
78 | strcpy(best_line,ue->ut_line); | |
79 | best_idle= stab.st_atime; | |
80 | } | |
81 | if (errno) { perror("getutent set errno"); exit(8); } | |
82 | ||
83 | switch (closest) { | |
84 | case hb_notlogon: problem("is not logged on"); | |
85 | case hb_noterminal: problem("does not have any terminal/shell sessions"); | |
86 | case hb_nomessages: problem("is refusing messages"); | |
87 | case hb_ok: break; | |
88 | default: abort(); | |
89 | } | |
90 | ||
91 | sprintf(idlebuf,"%lu",(unsigned long)best_idle); | |
92 | ||
93 | fd= open(best_line, O_NOCTTY|O_NONBLOCK|O_WRONLY); | |
94 | if (fd < 0) { | |
95 | fprintf(stderr,"unable to open terminal (%s): %s",best_line,strerror(errno)); | |
96 | exit(8); | |
97 | } | |
98 | if (dup2(fd,0)) { perror("dup2"); exit(8); } | |
99 | execlp(argv[1],argv[1], best_line,idlebuf,argv[2],argv[3],argv[4], (const char*)0); | |
100 | perror(argv[1]); exit(8); | |
101 | } |