diff options
Diffstat (limited to 'src/misc/lockf.c')
-rw-r--r-- | src/misc/lockf.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/misc/lockf.c b/src/misc/lockf.c new file mode 100644 index 0000000..d8f82ef --- /dev/null +++ b/src/misc/lockf.c @@ -0,0 +1,33 @@ +#include <unistd.h> +#include <fcntl.h> +#include <errno.h> +#include "libc.h" + +int lockf(int fd, int op, off_t size) +{ + struct flock l = { + .l_type = F_WRLCK, + .l_whence = SEEK_CUR, + .l_len = size, + }; + switch (op) { + case F_TEST: + l.l_type = F_RDLCK; + if (fcntl(fd, F_GETLK, &l) < 0) + return -1; + if (l.l_type == F_UNLCK || l.l_pid == getpid()) + return 0; + errno = EACCES; + return -1; + case F_ULOCK: + l.l_type = F_UNLCK; + case F_TLOCK: + return fcntl(fd, F_SETLK, &l); + case F_LOCK: + return fcntl(fd, F_SETLKW, &l); + } + errno = EINVAL; + return -1; +} + +LFS64(lockf); |