diff options
Diffstat (limited to 'libebtc.c')
| -rw-r--r-- | libebtc.c | 49 |
1 files changed, 5 insertions, 44 deletions
@@ -31,6 +31,7 @@ #include "include/ethernetdb.h" #include <unistd.h> #include <fcntl.h> +#include <sys/file.h> #include <sys/wait.h> #include <sys/stat.h> #include <sys/types.h> @@ -137,58 +138,18 @@ void ebt_list_extensions() #define LOCKDIR "/var/lib/ebtables" #define LOCKFILE LOCKDIR"/lock" #endif -static int lockfd = -1, locked; int use_lockfd; /* Returns 0 on success, -1 when the file is locked by another process * or -2 on any other error. */ static int lock_file() { - int try = 0; - int ret = 0; - sigset_t sigset; - -tryagain: - /* the SIGINT handler will call unlock_file. To make sure the state - * of the variable locked is correct, we need to temporarily mask the - * SIGINT interrupt. */ - sigemptyset(&sigset); - sigaddset(&sigset, SIGINT); - sigprocmask(SIG_BLOCK, &sigset, NULL); - lockfd = open(LOCKFILE, O_CREAT | O_EXCL | O_WRONLY, 00600); - if (lockfd < 0) { - if (errno == EEXIST) - ret = -1; - else if (try == 1) - ret = -2; - else { - if (mkdir(LOCKDIR, 00700)) - ret = -2; - else { - try = 1; - goto tryagain; - } - } - } else { - close(lockfd); - locked = 1; - } - sigprocmask(SIG_UNBLOCK, &sigset, NULL); - return ret; -} + int fd = open(LOCKFILE, O_CREAT, 00600); -void unlock_file() -{ - if (locked) { - remove(LOCKFILE); - locked = 0; - } + if (fd < 0) + return -2; + return flock(fd, LOCK_EX); } -void __attribute__ ((destructor)) onexit() -{ - if (use_lockfd) - unlock_file(); -} /* Get the table from the kernel or from a binary file * init: 1 = ask the kernel for the initial contents of a table, i.e. the * way it looks when the table is insmod'ed |