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758edcef SL |
1 | #ifndef lint |
2 | static char sccsid[] = "@(#)ulockf.c 5.1 (Berkeley) %G%"; | |
3 | #endif | |
4 | ||
5 | #include "uucp.h" | |
6 | #include <sys/types.h> | |
7 | #include <sys/stat.h> | |
8 | ||
9 | ||
10 | extern time_t time(); | |
11 | ||
12 | /* File mode for lock files */ | |
13 | #define LCKMODE 0444 | |
14 | ||
15 | /******* | |
16 | * ulockf(file, atime) | |
17 | * char *file; | |
18 | * time_t atime; | |
19 | * | |
20 | * ulockf - this routine will create a lock file (file). | |
21 | * If one already exists, the create time is checked for | |
22 | * older than the age time (atime). | |
23 | * If it is older, an attempt will be made to unlink it | |
24 | * and create a new one. | |
25 | * | |
26 | * return codes: 0 | FAIL | |
27 | */ | |
28 | ||
29 | ulockf(file, atime) | |
30 | register char *file; | |
31 | time_t atime; | |
32 | { | |
33 | struct stat stbuf; | |
34 | time_t ptime; | |
35 | register int ret; | |
36 | static int pid = -1; | |
37 | static char tempfile[NAMESIZE]; | |
38 | ||
39 | if (pid < 0) { | |
40 | pid = getpid(); | |
41 | sprintf(tempfile, "LTMP.%d", pid); | |
42 | } | |
43 | if (onelock(pid, tempfile, file) == -1) { | |
44 | /* lock file exists */ | |
45 | /* get status to check age of the lock file */ | |
46 | ret = stat(file, &stbuf); | |
47 | if (ret != -1) { | |
48 | time(&ptime); | |
49 | if ((ptime - stbuf.st_ctime) < atime) { | |
50 | /* file not old enough to delete */ | |
51 | return(FAIL); | |
52 | } | |
53 | } | |
54 | ret = unlink(file); | |
55 | ret = onelock(pid, tempfile, file); | |
56 | if (ret != 0) | |
57 | return(FAIL); | |
58 | } | |
59 | stlock(file); | |
60 | return(0); | |
61 | } | |
62 | ||
63 | ||
64 | #define MAXLOCKS 10 /* maximum number of lock files */ | |
65 | char *Lockfile[MAXLOCKS]; | |
66 | int Nlocks = 0; | |
67 | ||
68 | /*** | |
69 | * stlock(name) put name in list of lock files | |
70 | * char *name; | |
71 | * | |
72 | * return codes: none | |
73 | */ | |
74 | ||
75 | stlock(name) | |
76 | register char *name; | |
77 | { | |
78 | register char *p; | |
79 | register int i; | |
80 | ||
81 | for (i = 0; i < Nlocks; i++) { | |
82 | if (Lockfile[i] == NULL) | |
83 | break; | |
84 | } | |
85 | ASSERT(i < MAXLOCKS, "TOO MANY LOCKS", "", i); | |
86 | if (i >= Nlocks) | |
87 | i = Nlocks++; | |
88 | p = calloc((unsigned)(strlen(name)+1), sizeof (char)); | |
89 | ASSERT(p != NULL, "CAN NOT ALLOCATE FOR", name, 0); | |
90 | strcpy(p, name); | |
91 | Lockfile[i] = p; | |
92 | return; | |
93 | } | |
94 | ||
95 | ||
96 | /*** | |
97 | * rmlock(name) remove all lock files in list | |
98 | * char *name; or name | |
99 | * | |
100 | * return codes: none | |
101 | */ | |
102 | ||
103 | rmlock(name) | |
104 | register char *name; | |
105 | { | |
106 | register int i; | |
107 | ||
108 | for (i = 0; i < Nlocks; i++) { | |
109 | if (Lockfile[i] == NULL) | |
110 | continue; | |
111 | if (name == NULL | |
112 | || strcmp(name, Lockfile[i]) == SAME) { | |
113 | unlink(Lockfile[i]); | |
114 | free(Lockfile[i]); | |
115 | Lockfile[i] = NULL; | |
116 | } | |
117 | } | |
118 | return; | |
119 | } | |
120 | ||
121 | ||
122 | /* | |
123 | * this stuff from pjw | |
124 | * /usr/pjw/bin/recover - Check pids to remove unnecessary locks. | |
125 | * isalock(name) returns 0 if the name is a lock. | |
126 | * unlock(name) unlocks name if it is a lock. | |
127 | * onelock(pid,tempfile,name) makes lock a name | |
128 | * on behalf of pid. Tempfile must be in the same | |
129 | * file system as name. | |
130 | * lock(pid,tempfile,names) either locks all the | |
131 | * names or none of them. | |
132 | */ | |
133 | isalock(name) char *name; | |
134 | { | |
135 | struct stat xstat; | |
136 | if(stat(name,&xstat)<0) return(0); | |
137 | if(xstat.st_size!=sizeof(int)) return(0); | |
138 | return(1); | |
139 | } | |
140 | unlock(name) char *name; | |
141 | { | |
142 | if(isalock(name)) return(unlink(name)); | |
143 | else return(-1); | |
144 | } | |
145 | onelock(pid,tempfile,name) char *tempfile,*name; | |
146 | { register int fd; | |
147 | fd=creat(tempfile,LCKMODE); | |
148 | if(fd<0) return(-1); | |
149 | write(fd,(char *) &pid,sizeof(int)); | |
150 | close(fd); | |
151 | if(link(tempfile,name)<0) | |
152 | { unlink(tempfile); | |
153 | return(-1); | |
154 | } | |
155 | unlink(tempfile); | |
156 | return(0); | |
157 | } | |
158 | lock(pid,tempfile,names) char *tempfile; | |
159 | register char **names; | |
160 | { register int i,j; | |
161 | for(i=0;names[i]!=0;i++) | |
162 | { if(onelock(pid,tempfile,names[i])==0) continue; | |
163 | for(j=0;j<i;j++) unlink(names[j]); | |
164 | return(-1); | |
165 | } | |
166 | return(0); | |
167 | } | |
168 | ||
169 | #define LOCKPRE "LCK." | |
170 | ||
171 | /*** | |
172 | * delock(s) remove a lock file | |
173 | * char *s; | |
174 | * | |
175 | * return codes: 0 | FAIL | |
176 | */ | |
177 | ||
178 | delock(s) | |
179 | char *s; | |
180 | { | |
181 | char ln[30]; | |
182 | ||
183 | sprintf(ln, "%s.%s", LOCKPRE, s); | |
184 | rmlock(ln); | |
185 | } | |
186 | ||
187 | ||
188 | /*** | |
189 | * mlock(sys) create system lock | |
190 | * char *sys; | |
191 | * | |
192 | * return codes: 0 | FAIL | |
193 | */ | |
194 | ||
195 | mlock(sys) | |
196 | char *sys; | |
197 | { | |
198 | char lname[30]; | |
199 | sprintf(lname, "%s.%s", LOCKPRE, sys); | |
200 | return(ulockf(lname, (time_t) SLCKTIME ) < 0 ? FAIL : 0); | |
201 | } | |
202 | ||
203 | ||
204 | /*** | |
205 | * ultouch() update 'change' time for lock files | |
206 | * | |
207 | * -- mod by rti!trt -- | |
208 | * Only update ctime, not mtime or atime. | |
209 | * The 'chmod' method permits cu(I)-like programs | |
210 | * to determine how long uucp has been on the line. | |
211 | * The old "change access, mod, and change time" method | |
212 | * can be had by defining OLDTOUCH | |
213 | * | |
214 | * return code - none | |
215 | */ | |
216 | ||
217 | ultouch() | |
218 | { | |
219 | time_t time(); | |
220 | static time_t lasttouch = 0; | |
221 | register int i; | |
222 | struct ut { | |
223 | time_t actime; | |
224 | time_t modtime; | |
225 | } ut; | |
226 | ||
227 | ut.actime = time(&ut.modtime); | |
228 | /* Do not waste time touching locking files too often */ | |
229 | /* (But, defend against backward time changes) */ | |
230 | if (ut.actime >= lasttouch && ut.actime < lasttouch+60) | |
231 | return; | |
232 | lasttouch = ut.actime; | |
233 | DEBUG(4, "ultouch\n", 0); | |
234 | ||
235 | for (i = 0; i < Nlocks; i++) { | |
236 | if (Lockfile[i] == NULL) | |
237 | continue; | |
238 | #ifdef OLDTOUCH | |
239 | utime(Lockfile[i], &ut); | |
240 | #else | |
241 | chmod(Lockfile[i], LCKMODE); | |
242 | #endif | |
243 | } | |
244 | } |