diff options
| -rw-r--r-- | lib/mountlist.c | 40 |
1 files changed, 39 insertions, 1 deletions
diff --git a/lib/mountlist.c b/lib/mountlist.c index 68fc41aa1..94430f83c 100644 --- a/lib/mountlist.c +++ b/lib/mountlist.c @@ -42,6 +42,19 @@ char *xrealloc (); char *xstrdup (); void error (); +#include <errno.h> +#ifndef errno +extern int errno; +#endif + +#ifdef HAVE_FCNTL_H +# include <fcntl.h> +#endif + +#ifdef HAVE_UNISTD_H +# include <unistd.h> +#endif + #if HAVE_SYS_PARAM_H # include <sys/param.h> #endif @@ -518,6 +531,29 @@ read_filesystem_list (need_fs_type, all_fs) char *table = MNTTAB; FILE *fp; int ret; + int lockfd = -1; + +# if defined F_RDLCK && defined F_SETLKW + /* MNTTAB_LOCK is a macro name of our own invention; it's not present in + e.g. Solaris 2.6. If the SVR4 folks ever define a macro + for this file name, we should use their macro name instead. + (Why not just lock MNTTAB directly? We don't know.) */ +# ifndef MNTTAB_LOCK +# define MNTTAB_LOCK "/etc/.mnttab.lock" +# endif + lockfd = open (MNTTAB_LOCK, O_RDONLY); + if (0 <= lockfd) + { + struct flock flock; + flock.l_type = F_RDLCK; + flock.l_whence = SEEK_SET; + flock.l_start = 0; + flock.l_len = 0; + while (fcntl (lockfd, F_SETLKW, &flock) == -1) + if (errno != EINTR) + return NULL; + } +# endif fp = fopen (table, "r"); if (fp == NULL) @@ -543,7 +579,9 @@ read_filesystem_list (need_fs_type, all_fs) if (ret > 0) return NULL; - if (fclose (fp) == EOF) + if (fclose (fp) == EOF) + return NULL; + if (0 <= lockfd && close (lockfd) != 0) return NULL; } #endif /* MOUNTED_GETMNTENT2. */ |