| 1 | /* uucplock.c 4.2 81/11/20 */ |
| 2 | /* |
| 3 | * defs that come from uucp.h |
| 4 | */ |
| 5 | #define NAMESIZE 15 |
| 6 | #define FAIL -1 |
| 7 | #define SAME 0 |
| 8 | #define SLCKTIME 5400 /* system/device timeout (LCK.. files) in seconds */ |
| 9 | #define ASSERT(e, f, v) if (!(e)) {\ |
| 10 | fprintf(stderr, "AERROR - (%s) ", "e");\ |
| 11 | fprintf(stderr, f, v);\ |
| 12 | finish(FAIL);\ |
| 13 | } |
| 14 | |
| 15 | #define LOCKPRE "/usr/spool/uucp/LCK." |
| 16 | |
| 17 | /* |
| 18 | * This code is taken almost directly from uucp and follows the same |
| 19 | * conventions. This is important since uucp and tip should |
| 20 | * respect each others locks. |
| 21 | */ |
| 22 | |
| 23 | /* ulockf 3.2 10/26/79 11:40:29 */ |
| 24 | /* #include "uucp.h" */ |
| 25 | #include <sys/types.h> |
| 26 | #include <sys/stat.h> |
| 27 | #include <stdio.h> |
| 28 | |
| 29 | /******* |
| 30 | * ulockf(file, atime) |
| 31 | * char *file; |
| 32 | * time_t atime; |
| 33 | * |
| 34 | * ulockf - this routine will create a lock file (file). |
| 35 | * If one already exists, the create time is checked for |
| 36 | * older than the age time (atime). |
| 37 | * If it is older, an attempt will be made to unlink it |
| 38 | * and create a new one. |
| 39 | * |
| 40 | * return codes: 0 | FAIL |
| 41 | */ |
| 42 | |
| 43 | static |
| 44 | ulockf(file, atime) |
| 45 | char *file; |
| 46 | time_t atime; |
| 47 | { |
| 48 | struct stat stbuf; |
| 49 | time_t ptime; |
| 50 | int ret; |
| 51 | static int pid = -1; |
| 52 | static char tempfile[NAMESIZE]; |
| 53 | |
| 54 | if (pid < 0) { |
| 55 | pid = getpid(); |
| 56 | sprintf(tempfile, "/usr/spool/uucp/LTMP.%d", pid); |
| 57 | } |
| 58 | if (onelock(pid, tempfile, file) == -1) { |
| 59 | /* lock file exists */ |
| 60 | /* get status to check age of the lock file */ |
| 61 | ret = stat(file, &stbuf); |
| 62 | if (ret != -1) { |
| 63 | time(&ptime); |
| 64 | if ((ptime - stbuf.st_ctime) < atime) { |
| 65 | /* file not old enough to delete */ |
| 66 | return(FAIL); |
| 67 | } |
| 68 | } |
| 69 | ret = unlink(file); |
| 70 | ret = onelock(pid, tempfile, file); |
| 71 | if (ret != 0) |
| 72 | return(FAIL); |
| 73 | } |
| 74 | stlock(file); |
| 75 | return(0); |
| 76 | } |
| 77 | |
| 78 | #define MAXLOCKS 10 /* maximum number of lock files */ |
| 79 | char *Lockfile[MAXLOCKS]; |
| 80 | int Nlocks = 0; |
| 81 | |
| 82 | /*** |
| 83 | * stlock(name) put name in list of lock files |
| 84 | * char *name; |
| 85 | * |
| 86 | * return codes: none |
| 87 | */ |
| 88 | |
| 89 | static |
| 90 | stlock(name) |
| 91 | char *name; |
| 92 | { |
| 93 | char *p; |
| 94 | extern char *calloc(); |
| 95 | int i; |
| 96 | |
| 97 | for (i = 0; i < Nlocks; i++) { |
| 98 | if (Lockfile[i] == NULL) |
| 99 | break; |
| 100 | } |
| 101 | ASSERT(i < MAXLOCKS, "TOO MANY LOCKS %d", i); |
| 102 | if (i >= Nlocks) |
| 103 | i = Nlocks++; |
| 104 | p = calloc(strlen(name) + 1, sizeof (char)); |
| 105 | ASSERT(p != NULL, "CAN NOT ALLOCATE FOR %s", name); |
| 106 | strcpy(p, name); |
| 107 | Lockfile[i] = p; |
| 108 | return; |
| 109 | } |
| 110 | |
| 111 | /*** |
| 112 | * rmlock(name) remove all lock files in list |
| 113 | * char *name; or name |
| 114 | * |
| 115 | * return codes: none |
| 116 | */ |
| 117 | |
| 118 | static |
| 119 | rmlock(name) |
| 120 | char *name; |
| 121 | { |
| 122 | int i; |
| 123 | |
| 124 | for (i = 0; i < Nlocks; i++) { |
| 125 | if (Lockfile[i] == NULL) |
| 126 | continue; |
| 127 | if (name == NULL |
| 128 | || strcmp(name, Lockfile[i]) == SAME) { |
| 129 | unlink(Lockfile[i]); |
| 130 | free(Lockfile[i]); |
| 131 | Lockfile[i] = NULL; |
| 132 | } |
| 133 | } |
| 134 | return; |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * this stuff from pjw |
| 139 | * /usr/pjw/bin/recover - check pids to remove unnecessary locks |
| 140 | * |
| 141 | * isalock(name) returns 0 if the name is a lock |
| 142 | * |
| 143 | * onelock(pid,tempfile,name) makes lock a name |
| 144 | * on behalf of pid. Tempfile must be in the same |
| 145 | * file system as name. |
| 146 | * |
| 147 | * lock(pid,tempfile,names) either locks all the |
| 148 | * names or none of them |
| 149 | */ |
| 150 | static |
| 151 | isalock(name) |
| 152 | char *name; |
| 153 | { |
| 154 | struct stat xstat; |
| 155 | |
| 156 | if(stat(name,&xstat)<0) |
| 157 | return(0); |
| 158 | if(xstat.st_size!=sizeof(int)) |
| 159 | return(0); |
| 160 | return(1); |
| 161 | } |
| 162 | |
| 163 | static |
| 164 | onelock(pid,tempfile,name) |
| 165 | char *tempfile,*name; |
| 166 | { |
| 167 | int fd; |
| 168 | |
| 169 | fd=creat(tempfile,0444); |
| 170 | if(fd<0) |
| 171 | return(-1); |
| 172 | write(fd,(char *) &pid,sizeof(int)); |
| 173 | close(fd); |
| 174 | if(link(tempfile,name)<0) { |
| 175 | unlink(tempfile); |
| 176 | return(-1); |
| 177 | } |
| 178 | unlink(tempfile); |
| 179 | return(0); |
| 180 | } |
| 181 | |
| 182 | /*** |
| 183 | * delock(s) remove a lock file |
| 184 | * char *s; |
| 185 | * |
| 186 | * return codes: 0 | FAIL |
| 187 | */ |
| 188 | |
| 189 | delock(s) |
| 190 | char *s; |
| 191 | { |
| 192 | char ln[30]; |
| 193 | |
| 194 | sprintf(ln, "%s.%s", LOCKPRE, s); |
| 195 | rmlock(ln); |
| 196 | } |
| 197 | |
| 198 | /*** |
| 199 | * mlock(sys) create system lock |
| 200 | * char *sys; |
| 201 | * |
| 202 | * return codes: 0 | FAIL |
| 203 | */ |
| 204 | |
| 205 | mlock(sys) |
| 206 | char *sys; |
| 207 | { |
| 208 | char lname[30]; |
| 209 | sprintf(lname, "%s.%s", LOCKPRE, sys); |
| 210 | return(ulockf(lname, (time_t) SLCKTIME ) < 0 ? FAIL : 0); |
| 211 | } |