Commit | Line | Data |
---|---|---|
2c554823 KS |
1 | # |
2 | ||
3 | /* | |
4 | * A mailing program. | |
5 | * | |
6 | * Stuff to do version 7 style locking. | |
7 | */ | |
8 | ||
9 | #include "rcv.h" | |
10 | #include <sys/stat.h> | |
11 | ||
7a36cf49 | 12 | static char *SccsId = "@(#)lock.c 2.2 %G%"; |
2c554823 | 13 | |
1a27a241 | 14 | char *maillock = ".mail"; /* Lock suffix for mailname */ |
2c554823 KS |
15 | char *lockname = "/usr/spool/mail/tmXXXXXX"; |
16 | char locktmp[30]; /* Usable lock temporary */ | |
17 | static char curlock[50]; /* Last used name of lock */ | |
18 | static int locked; /* To note that we locked it */ | |
19 | ||
20 | /* | |
21 | * Lock the specified mail file by setting the file mailfile.lock. | |
22 | * We must, of course, be careful to remove the lock file by a call | |
23 | * to unlock before we stop. The algorithm used here is to see if | |
24 | * the lock exists, and if it does, to check its modify time. If it | |
7a36cf49 | 25 | * is older than 5 minutes, we assume error and set our own file. |
2c554823 KS |
26 | * Otherwise, we wait for 5 seconds and try again. |
27 | */ | |
28 | ||
29 | lock(file) | |
30 | char *file; | |
31 | { | |
32 | register int f; | |
33 | struct stat sbuf; | |
34 | long curtime; | |
35 | ||
36 | if (file == NOSTR) { | |
37 | printf("Locked = %d\n", locked); | |
38 | return(0); | |
39 | } | |
40 | if (locked) | |
41 | return(0); | |
42 | strcpy(curlock, file); | |
43 | strcat(curlock, maillock); | |
44 | strcpy(locktmp, lockname); | |
45 | mktemp(locktmp); | |
46 | remove(locktmp); | |
47 | for (;;) { | |
48 | f = lock1(locktmp, curlock); | |
49 | if (f == 0) { | |
50 | locked = 1; | |
51 | return(0); | |
52 | } | |
53 | if (stat(curlock, &sbuf) < 0) | |
54 | return(0); | |
55 | time(&curtime); | |
7a36cf49 | 56 | if (curtime < sbuf.st_ctime + 300) { |
2c554823 KS |
57 | sleep(5); |
58 | continue; | |
59 | } | |
60 | remove(curlock); | |
61 | } | |
62 | } | |
63 | ||
64 | /* | |
65 | * Remove the mail lock, and note that we no longer | |
66 | * have it locked. | |
67 | */ | |
68 | ||
69 | unlock() | |
70 | { | |
71 | ||
72 | remove(curlock); | |
73 | locked = 0; | |
74 | } | |
75 | ||
76 | /* | |
77 | * Attempt to set the lock by creating the temporary file, | |
78 | * then doing a link/unlink. If it fails, return -1 else 0 | |
79 | */ | |
80 | ||
81 | lock1(tempfile, name) | |
82 | char tempfile[], name[]; | |
83 | { | |
84 | register int fd; | |
85 | ||
86 | fd = creat(tempfile, 0); | |
87 | if (fd < 0) | |
88 | return(-1); | |
89 | close(fd); | |
90 | if (link(tempfile, name) < 0) { | |
91 | remove(tempfile); | |
92 | return(-1); | |
93 | } | |
94 | remove(tempfile); | |
95 | return(0); | |
96 | } |