X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fceph%2Fsrc%2Fmount%2Fmtab.c;fp=src%2Fceph%2Fsrc%2Fmount%2Fmtab.c;h=0000000000000000000000000000000000000000;hb=7da45d65be36d36b880cc55c5036e96c24b53f00;hp=4dc82bb34faa22bc1cfbfbaa78a0829a4d50cfcf;hpb=691462d09d0987b47e112d6ee8740375df3c51b2;p=stor4nfv.git diff --git a/src/ceph/src/mount/mtab.c b/src/ceph/src/mount/mtab.c deleted file mode 100644 index 4dc82bb..0000000 --- a/src/ceph/src/mount/mtab.c +++ /dev/null @@ -1,294 +0,0 @@ - -/* - * this code lifted from util-linux-ng, licensed GPLv2+, - * - * git://git.kernel.org/pub/scm/utils/util-linux-ng/util-linux-ng.git - * - * whoever decided that each special mount program is responsible - * for updating /etc/mtab should be spanked. - * - * - */ -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include "mount/canonicalize.c" - - -/* Updating mtab ----------------------------------------------*/ - -/* Flag for already existing lock file. */ -static int we_created_lockfile = 0; -static int lockfile_fd = -1; - -/* Flag to indicate that signals have been set up. */ -static int signals_have_been_setup = 0; - -/* Ensure that the lock is released if we are interrupted. */ -extern char *strsignal(int sig); /* not always in */ - -static void -setlkw_timeout (int sig) { - /* nothing, fcntl will fail anyway */ -} - -#define _PATH_MOUNTED "/etc/mtab" -#define _PATH_MOUNTED_LOCK "/etc/mtab~" -#define PROC_SUPER_MAGIC 0x9fa0 - -/* exit status - bits below are ORed */ -#define EX_USAGE 1 /* incorrect invocation or permission */ -#define EX_SYSERR 2 /* out of memory, cannot fork, ... */ -#define EX_SOFTWARE 4 /* internal mount bug or wrong version */ -#define EX_USER 8 /* user interrupt */ -#define EX_FILEIO 16 /* problems writing, locking, ... mtab/fstab */ -#define EX_FAIL 32 /* mount failure */ -#define EX_SOMEOK 64 /* some mount succeeded */ - -int die(int err, const char *fmt, ...) { - va_list args; - - va_start(args, fmt); - vfprintf(stderr, fmt, args); - fprintf(stderr, "\n"); - va_end(args); - - exit(err); -} - -static void -handler (int sig) { - die(EX_USER, "%s", strsignal(sig)); -} - -/* Remove lock file. */ -void -unlock_mtab (void) { - if (we_created_lockfile) { - close(lockfile_fd); - lockfile_fd = -1; - unlink (_PATH_MOUNTED_LOCK); - we_created_lockfile = 0; - } -} - -/* Create the lock file. - The lock file will be removed if we catch a signal or when we exit. */ -/* The old code here used flock on a lock file /etc/mtab~ and deleted - this lock file afterwards. However, as rgooch remarks, that has a - race: a second mount may be waiting on the lock and proceed as - soon as the lock file is deleted by the first mount, and immediately - afterwards a third mount comes, creates a new /etc/mtab~, applies - flock to that, and also proceeds, so that the second and third mount - now both are scribbling in /etc/mtab. - The new code uses a link() instead of a creat(), where we proceed - only if it was us that created the lock, and hence we always have - to delete the lock afterwards. Now the use of flock() is in principle - superfluous, but avoids an arbitrary sleep(). */ - -/* Where does the link point to? Obvious choices are mtab and mtab~~. - HJLu points out that the latter leads to races. Right now we use - mtab~. instead. Use 20 as upper bound for the length of %d. */ -#define MOUNTLOCK_LINKTARGET _PATH_MOUNTED_LOCK "%d" -#define MOUNTLOCK_LINKTARGET_LTH (sizeof(_PATH_MOUNTED_LOCK)+20) - -/* - * The original mount locking code has used sleep(1) between attempts and - * maximal number of attemps has been 5. - * - * There was very small number of attempts and extremely long waiting (1s) - * that is useless on machines with large number of concurret mount processes. - * - * Now we wait few thousand microseconds between attempts and we have global - * time limit (30s) rather than limit for number of attempts. The advantage - * is that this method also counts time which we spend in fcntl(F_SETLKW) and - * number of attempts is not so much restricted. - * - * -- kzak@redhat.com [2007-Mar-2007] - */ - -/* maximum seconds between first and last attempt */ -#define MOUNTLOCK_MAXTIME 30 - -/* sleep time (in microseconds, max=999999) between attempts */ -#define MOUNTLOCK_WAITTIME 5000 - -void -lock_mtab (void) { - int i; - struct timespec waittime; - struct timeval maxtime; - char linktargetfile[MOUNTLOCK_LINKTARGET_LTH]; - - if (!signals_have_been_setup) { - int sig = 0; - struct sigaction sa; - - sa.sa_handler = handler; - sa.sa_flags = 0; - sigfillset (&sa.sa_mask); - - while (sigismember (&sa.sa_mask, ++sig) != -1 - && sig != SIGCHLD) { - if (sig == SIGALRM) - sa.sa_handler = setlkw_timeout; - else - sa.sa_handler = handler; - sigaction (sig, &sa, (struct sigaction *) 0); - } - signals_have_been_setup = 1; - } - - snprintf(linktargetfile, sizeof(linktargetfile), MOUNTLOCK_LINKTARGET, - getpid ()); - - i = open (linktargetfile, O_WRONLY|O_CREAT, S_IRUSR|S_IWUSR); - if (i < 0) { - int errsv = errno; - /* linktargetfile does not exist (as a file) - and we cannot create it. Read-only filesystem? - Too many files open in the system? - Filesystem full? */ - die (EX_FILEIO, "can't create lock file %s: %s " - "(use -n flag to override)", - linktargetfile, strerror (errsv)); - } - close(i); - - gettimeofday(&maxtime, NULL); - maxtime.tv_sec += MOUNTLOCK_MAXTIME; - - waittime.tv_sec = 0; - waittime.tv_nsec = (1000 * MOUNTLOCK_WAITTIME); - - /* Repeat until it was us who made the link */ - while (!we_created_lockfile) { - struct timeval now; - struct flock flock; - int errsv, j; - - j = link(linktargetfile, _PATH_MOUNTED_LOCK); - errsv = errno; - - if (j == 0) - we_created_lockfile = 1; - - if (j < 0 && errsv != EEXIST) { - (void) unlink(linktargetfile); - die (EX_FILEIO, "can't link lock file %s: %s " - "(use -n flag to override)", - _PATH_MOUNTED_LOCK, strerror (errsv)); - } - - lockfile_fd = open (_PATH_MOUNTED_LOCK, O_WRONLY); - - if (lockfile_fd < 0) { - /* Strange... Maybe the file was just deleted? */ - int errsv = errno; - gettimeofday(&now, NULL); - if (errno == ENOENT && now.tv_sec < maxtime.tv_sec) { - we_created_lockfile = 0; - continue; - } - (void) unlink(linktargetfile); - die (EX_FILEIO, "can't open lock file %s: %s " - "(use -n flag to override)", - _PATH_MOUNTED_LOCK, strerror (errsv)); - } - - flock.l_type = F_WRLCK; - flock.l_whence = SEEK_SET; - flock.l_start = 0; - flock.l_len = 0; - - if (j == 0) { - /* We made the link. Now claim the lock. */ - if (fcntl (lockfile_fd, F_SETLK, &flock) == -1) { - /* proceed, since it was us who created the lockfile anyway */ - } - (void) unlink(linktargetfile); - } else { - /* Someone else made the link. Wait. */ - gettimeofday(&now, NULL); - if (now.tv_sec < maxtime.tv_sec) { - alarm(maxtime.tv_sec - now.tv_sec); - if (fcntl (lockfile_fd, F_SETLKW, &flock) == -1) { - int errsv = errno; - (void) unlink(linktargetfile); - die (EX_FILEIO, "can't lock lock file %s: %s", - _PATH_MOUNTED_LOCK, (errno == EINTR) ? - "timed out" : strerror (errsv)); - } - alarm(0); - - nanosleep(&waittime, NULL); - } else { - (void) unlink(linktargetfile); - die (EX_FILEIO, "Cannot create link %s\n" - "Perhaps there is a stale lock file?\n", - _PATH_MOUNTED_LOCK); - } - close(lockfile_fd); - } - } -} - -static void -update_mtab_entry(const char *spec, const char *node, const char *type, - const char *opts, int flags, int freq, int pass) { - struct statfs buf; - int err = statfs(_PATH_MOUNTED, &buf); - if (err) { - printf("mount: can't statfs %s: %s", _PATH_MOUNTED, - strerror (err)); - return; - } - /* /etc/mtab is symbol link to /proc/self/mounts? */ - if (buf.f_type == PROC_SUPER_MAGIC) - return; - - if (!opts) - opts = "rw"; - - struct mntent mnt; - mnt.mnt_fsname = strdup(spec); - mnt.mnt_dir = canonicalize_path(node); - mnt.mnt_type = strdup(type); - mnt.mnt_opts = strdup(opts); - mnt.mnt_freq = freq; - mnt.mnt_passno = pass; - - FILE *fp; - - lock_mtab(); - fp = setmntent(_PATH_MOUNTED, "a+"); - if (fp == NULL) { - int errsv = errno; - printf("mount: can't open %s: %s", _PATH_MOUNTED, - strerror (errsv)); - } else { - if ((addmntent (fp, &mnt)) == 1) { - int errsv = errno; - printf("mount: error writing %s: %s", - _PATH_MOUNTED, strerror (errsv)); - } - } - endmntent(fp); - unlock_mtab(); - - free(mnt.mnt_fsname); - free(mnt.mnt_dir); - free(mnt.mnt_type); - free(mnt.mnt_opts); -}