| 1 | /* We save the locks so we can reaquire them. */
|
|---|
| 2 | #include "../common/tdb_private.h"
|
|---|
| 3 | #include <unistd.h>
|
|---|
| 4 | #include <fcntl.h>
|
|---|
| 5 | #include <stdarg.h>
|
|---|
| 6 | #include <stdlib.h>
|
|---|
| 7 | #include "tap-interface.h"
|
|---|
| 8 | #include "lock-tracking.h"
|
|---|
| 9 |
|
|---|
| 10 | struct testlock {
|
|---|
| 11 | struct testlock *next;
|
|---|
| 12 | unsigned int off;
|
|---|
| 13 | unsigned int len;
|
|---|
| 14 | int type;
|
|---|
| 15 | };
|
|---|
| 16 | static struct testlock *testlocks;
|
|---|
| 17 | int locking_errors = 0;
|
|---|
| 18 | bool suppress_lockcheck = false;
|
|---|
| 19 | bool nonblocking_locks;
|
|---|
| 20 | int locking_would_block = 0;
|
|---|
| 21 | void (*unlock_callback)(int fd);
|
|---|
| 22 |
|
|---|
| 23 | int fcntl_with_lockcheck(int fd, int cmd, ... /* arg */ )
|
|---|
| 24 | {
|
|---|
| 25 | va_list ap;
|
|---|
| 26 | int ret, arg3;
|
|---|
| 27 | struct flock *fl;
|
|---|
| 28 | bool may_block = false;
|
|---|
| 29 |
|
|---|
| 30 | if (cmd != F_SETLK && cmd != F_SETLKW) {
|
|---|
| 31 | /* This may be totally bogus, but we don't know in general. */
|
|---|
| 32 | va_start(ap, cmd);
|
|---|
| 33 | arg3 = va_arg(ap, int);
|
|---|
| 34 | va_end(ap);
|
|---|
| 35 |
|
|---|
| 36 | return fcntl(fd, cmd, arg3);
|
|---|
| 37 | }
|
|---|
| 38 |
|
|---|
| 39 | va_start(ap, cmd);
|
|---|
| 40 | fl = va_arg(ap, struct flock *);
|
|---|
| 41 | va_end(ap);
|
|---|
| 42 |
|
|---|
| 43 | if (cmd == F_SETLKW && nonblocking_locks) {
|
|---|
| 44 | cmd = F_SETLK;
|
|---|
| 45 | may_block = true;
|
|---|
| 46 | }
|
|---|
| 47 | ret = fcntl(fd, cmd, fl);
|
|---|
| 48 |
|
|---|
| 49 | /* Detect when we failed, but might have been OK if we waited. */
|
|---|
| 50 | if (may_block && ret == -1 && (errno == EAGAIN || errno == EACCES)) {
|
|---|
| 51 | locking_would_block++;
|
|---|
| 52 | }
|
|---|
| 53 |
|
|---|
| 54 | if (fl->l_type == F_UNLCK) {
|
|---|
| 55 | struct testlock **l;
|
|---|
| 56 | struct testlock *old = NULL;
|
|---|
| 57 |
|
|---|
| 58 | for (l = &testlocks; *l; l = &(*l)->next) {
|
|---|
| 59 | if ((*l)->off == fl->l_start
|
|---|
| 60 | && (*l)->len == fl->l_len) {
|
|---|
| 61 | if (ret == 0) {
|
|---|
| 62 | old = *l;
|
|---|
| 63 | *l = (*l)->next;
|
|---|
| 64 | free(old);
|
|---|
| 65 | }
|
|---|
| 66 | break;
|
|---|
| 67 | }
|
|---|
| 68 | if (((*l)->off == fl->l_start)
|
|---|
| 69 | && ((*l)->len == 0)
|
|---|
| 70 | && (ret == 0)) {
|
|---|
| 71 | /*
|
|---|
| 72 | * Remove a piece from the start of the
|
|---|
| 73 | * allrecord_lock
|
|---|
| 74 | */
|
|---|
| 75 | old = *l;
|
|---|
| 76 | (*l)->off += fl->l_len;
|
|---|
| 77 | break;
|
|---|
| 78 | }
|
|---|
| 79 | }
|
|---|
| 80 | if (!old && !suppress_lockcheck) {
|
|---|
| 81 | diag("Unknown unlock %u@%u - %i",
|
|---|
| 82 | (int)fl->l_len, (int)fl->l_start, ret);
|
|---|
| 83 | locking_errors++;
|
|---|
| 84 | }
|
|---|
| 85 | } else {
|
|---|
| 86 | struct testlock *new, *i;
|
|---|
| 87 | unsigned int fl_end = fl->l_start + fl->l_len;
|
|---|
| 88 | if (fl->l_len == 0)
|
|---|
| 89 | fl_end = (unsigned int)-1;
|
|---|
| 90 |
|
|---|
| 91 | /* Check for overlaps: we shouldn't do this. */
|
|---|
| 92 | for (i = testlocks; i; i = i->next) {
|
|---|
| 93 | unsigned int i_end = i->off + i->len;
|
|---|
| 94 | if (i->len == 0)
|
|---|
| 95 | i_end = (unsigned int)-1;
|
|---|
| 96 |
|
|---|
| 97 | if (fl->l_start >= i->off && fl->l_start < i_end)
|
|---|
| 98 | break;
|
|---|
| 99 | if (fl_end >= i->off && fl_end < i_end)
|
|---|
| 100 | break;
|
|---|
| 101 |
|
|---|
| 102 | /* tdb_allrecord_lock does this, handle adjacent: */
|
|---|
| 103 | if (fl->l_start == i_end && fl->l_type == i->type) {
|
|---|
| 104 | if (ret == 0) {
|
|---|
| 105 | i->len = fl->l_len
|
|---|
| 106 | ? i->len + fl->l_len
|
|---|
| 107 | : 0;
|
|---|
| 108 | }
|
|---|
| 109 | goto done;
|
|---|
| 110 | }
|
|---|
| 111 | }
|
|---|
| 112 | if (i) {
|
|---|
| 113 | /* Special case: upgrade of allrecord lock. */
|
|---|
| 114 | if (i->type == F_RDLCK && fl->l_type == F_WRLCK
|
|---|
| 115 | && i->off == FREELIST_TOP
|
|---|
| 116 | && fl->l_start == FREELIST_TOP
|
|---|
| 117 | && i->len == 0
|
|---|
| 118 | && fl->l_len == 0) {
|
|---|
| 119 | if (ret == 0)
|
|---|
| 120 | i->type = F_WRLCK;
|
|---|
| 121 | goto done;
|
|---|
| 122 | }
|
|---|
| 123 | if (!suppress_lockcheck) {
|
|---|
| 124 | diag("%s testlock %u@%u overlaps %u@%u",
|
|---|
| 125 | fl->l_type == F_WRLCK ? "write" : "read",
|
|---|
| 126 | (int)fl->l_len, (int)fl->l_start,
|
|---|
| 127 | i->len, (int)i->off);
|
|---|
| 128 | locking_errors++;
|
|---|
| 129 | }
|
|---|
| 130 | }
|
|---|
| 131 |
|
|---|
| 132 | if (ret == 0) {
|
|---|
| 133 | new = malloc(sizeof *new);
|
|---|
| 134 | new->off = fl->l_start;
|
|---|
| 135 | new->len = fl->l_len;
|
|---|
| 136 | new->type = fl->l_type;
|
|---|
| 137 | new->next = testlocks;
|
|---|
| 138 | testlocks = new;
|
|---|
| 139 | }
|
|---|
| 140 | }
|
|---|
| 141 | done:
|
|---|
| 142 | if (ret == 0 && fl->l_type == F_UNLCK && unlock_callback)
|
|---|
| 143 | unlock_callback(fd);
|
|---|
| 144 | return ret;
|
|---|
| 145 | }
|
|---|
| 146 |
|
|---|
| 147 | unsigned int forget_locking(void)
|
|---|
| 148 | {
|
|---|
| 149 | unsigned int num = 0;
|
|---|
| 150 | while (testlocks) {
|
|---|
| 151 | struct testlock *next = testlocks->next;
|
|---|
| 152 | free(testlocks);
|
|---|
| 153 | testlocks = next;
|
|---|
| 154 | num++;
|
|---|
| 155 | }
|
|---|
| 156 | return num;
|
|---|
| 157 | }
|
|---|
