X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/92a581153df9d0a44fd8cf75058cc9512bc40533..018ba359ab456f6a43f3acea0c15df616aa0ad02:/src/filelock.c diff --git a/src/filelock.c b/src/filelock.c index f5e4fb8596..bdfcda9ade 100644 --- a/src/filelock.c +++ b/src/filelock.c @@ -1,5 +1,6 @@ /* Lock files for editing. - Copyright (C) 1985, 86, 87, 93, 94, 96, 98, 1999 Free Software Foundation, Inc. + Copyright (C) 1985, 86, 87, 93, 94, 96, 98, 1999, 2000, 2001 + Free Software Foundation, Inc. This file is part of GNU Emacs. @@ -19,10 +20,11 @@ the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ +#include #include #include #include -#include +#include #ifdef VMS #include "vms-pwd.h" @@ -31,37 +33,46 @@ Boston, MA 02111-1307, USA. */ #endif /* not VMS */ #include -#ifdef USG +#ifdef HAVE_FCNTL_H #include +#endif +#ifdef HAVE_STRING_H #include -#endif /* USG */ +#endif #ifdef HAVE_UNISTD_H #include #endif #ifdef __FreeBSD__ -#include -#include #include #endif /* __FreeBSD__ */ +#include +#ifndef errno +extern int errno; +#endif + #include "lisp.h" #include "buffer.h" #include "charset.h" #include "coding.h" #include "systime.h" -#include -#include -#ifndef errno -extern int errno; -#endif +/* The directory for writing temporary files. */ + +Lisp_Object Vtemporary_file_directory; #ifdef CLASH_DETECTION #include +/* A file whose last-modified time is just after the most recent boot. + Define this to be NULL to disable checking for this file. */ +#ifndef BOOT_TIME_FILE +#define BOOT_TIME_FILE "/var/run/random-seed" +#endif + #ifndef WTMP_FILE #define WTMP_FILE "/var/log/wtmp" #endif @@ -109,53 +120,21 @@ static int boot_time_initialized; extern Lisp_Object Vshell_file_name; +#ifdef BOOT_TIME +static void get_boot_time_1 P_ ((char *, int)); +#endif + static time_t get_boot_time () { - struct utmp ut, *utp; - int fd; - EMACS_TIME time_before, after; +#if defined (BOOT_TIME) && ! defined (NO_WTMP_FILE) int counter; +#endif if (boot_time_initialized) return boot_time; boot_time_initialized = 1; - EMACS_GET_TIME (time_before); - - /* Try calculating the last boot time - from the uptime as obtained from /proc/uptime. - - This has a disadvantage in that if the system time has been - changed (say to correct the clock), - then current_time - uptime != wtmp_boot_time. - However, the speedup from doing this can be so great - that I think it is worth that problem occasionally. */ - - while ((fd = open ("/proc/uptime", O_RDONLY)) >= 0) - { - char buf[100]; - int res; - double upsecs; - time_t uptime; - - read (fd, buf, sizeof buf); - close (fd); - - res = sscanf (buf, "%lf", &upsecs); - - /* If the current time did not tick while we were getting the - uptime, we have a valid result. */ - EMACS_GET_TIME (after); - if (res == 1 && EMACS_SECS (after) == EMACS_SECS (time_before)) - { - boot_time = EMACS_SECS (time_before) - (time_t) upsecs; - return boot_time; - } - - /* Otherwise, try again to read the uptime. */ - time_before = after; - } #if defined (CTL_KERN) && defined (KERN_BOOTTIME) { int mib[2]; @@ -174,6 +153,16 @@ get_boot_time () } #endif /* defined (CTL_KERN) && defined (KERN_BOOTTIME) */ + if (BOOT_TIME_FILE) + { + struct stat st; + if (stat (BOOT_TIME_FILE, &st) == 0) + { + boot_time = st.st_mtime; + return boot_time; + } + } + #if defined (BOOT_TIME) && ! defined (NO_WTMP_FILE) #ifndef CANNOT_DUMP /* The utmp routines maintain static state. @@ -214,7 +203,15 @@ get_boot_time () if (! NILP (Ffile_exists_p (tempname))) { Lisp_Object args[6]; - tempname = Fmake_temp_name (build_string ("wtmp")); + + /* The utmp functions on mescaline.gnu.org accept only + file names up to 8 characters long. Choose a 2 + character long prefix, and call make_temp_file with + second arg non-zero, so that it will add not more + than 6 characters to the prefix. */ + tempname = Fexpand_file_name (build_string ("wt"), + Vtemporary_file_directory); + tempname = make_temp_name (tempname, 1); args[0] = Vshell_file_name; args[1] = Qnil; args[2] = Qnil; @@ -254,6 +251,7 @@ get_boot_time () Ignore all reboot records on or before BOOT_TIME. Success is indicated by setting BOOT_TIME to a larger value. */ +void get_boot_time_1 (filename, newest) char *filename; int newest; @@ -265,11 +263,11 @@ get_boot_time_1 (filename, newest) { /* On some versions of IRIX, opening a nonexistent file name is likely to crash in the utmp routines. */ - desc = open (filename, O_RDONLY); + desc = emacs_open (filename, O_RDONLY, 0); if (desc < 0) return; - close (desc); + emacs_close (desc); utmpname (filename); } @@ -319,9 +317,11 @@ typedef struct /* Write the name of the lock file for FN into LFNAME. Length will be - that of FN plus two more for the leading `.#' plus one for the null. */ + that of FN plus two more for the leading `.#' plus 1 for the + trailing period plus one for the digit after it plus one for the + null. */ #define MAKE_LOCK_NAME(lock, file) \ - (lock = (char *) alloca (STRING_BYTES (XSTRING (file)) + 2 + 1), \ + (lock = (char *) alloca (STRING_BYTES (XSTRING (file)) + 2 + 1 + 1 + 1), \ fill_in_lock_file_name (lock, (file))) static void @@ -330,6 +330,8 @@ fill_in_lock_file_name (lockfile, fn) register Lisp_Object fn; { register char *p; + struct stat st; + int count = 0; strcpy (lockfile, XSTRING (fn)->data); @@ -342,6 +344,18 @@ fill_in_lock_file_name (lockfile, fn) /* Insert the `.#'. */ p[1] = '.'; p[2] = '#'; + + p = p + strlen (p); + + while (lstat (lockfile, &st) == 0 && !S_ISLNK (st.st_mode)) + { + if (count > 9) + { + *p = '\0'; + return; + } + sprintf (p, ".%d", count++); + } } /* Lock the lock file named LFNAME. @@ -410,7 +424,7 @@ current_lock_owner (owner, lfname) #ifndef index extern char *rindex (), *index (); #endif - int o, p, len, ret; + int len, ret; int local_owner = 0; char *at, *dot, *colon; char *lfinfo = 0; @@ -421,7 +435,13 @@ current_lock_owner (owner, lfname) { bufsize *= 2; lfinfo = (char *) xrealloc (lfinfo, bufsize); + errno = 0; len = readlink (lfname, lfinfo, bufsize); +#ifdef ERANGE + /* HP-UX reports ERANGE if the buffer is too small. */ + if (len == -1 && errno == ERANGE) + len = bufsize; +#endif } while (len >= bufsize); @@ -521,7 +541,7 @@ lock_if_free (clasher, lfname) lock_info_type *clasher; register char *lfname; { - if (lock_file_1 (lfname, 0) == 0) + while (lock_file_1 (lfname, 0) == 0) { int locker; @@ -536,8 +556,10 @@ lock_if_free (clasher, lfname) } else if (locker == 1) return 1; /* Someone else has it. */ + else if (locker == -1) + return -1; /* current_lock_owner returned strange error. */ - return -1; /* Something's wrong. */ + /* We deleted a stale lock; try again to lock the file. */ } return 0; } @@ -566,8 +588,16 @@ lock_file (fn) register Lisp_Object attack, orig_fn, encoded_fn; register char *lfname, *locker; lock_info_type lock_info; + struct gcpro gcpro1; + + /* Don't do locking while dumping Emacs. + Uncompressing wtmp files uses call-process, which does not work + in an uninitialized Emacs. */ + if (! NILP (Vpurify_flag)) + return; orig_fn = fn; + GCPRO1 (fn); fn = Fexpand_file_name (fn, Qnil); encoded_fn = ENCODE_FILE (fn); @@ -578,18 +608,16 @@ lock_file (fn) visited. */ { register Lisp_Object subject_buf; - struct gcpro gcpro1; subject_buf = get_truename_buffer (orig_fn); - GCPRO1 (fn); if (!NILP (subject_buf) && NILP (Fverify_visited_file_modtime (subject_buf)) && !NILP (Ffile_exists_p (fn))) call1 (intern ("ask-user-about-supersession-threat"), fn); - UNGCPRO; } + UNGCPRO; /* Try to lock the lock. */ if (lock_if_free (&lock_info, lfname) <= 0) @@ -634,17 +662,12 @@ unlock_all_files () register Lisp_Object tail; register struct buffer *b; - for (tail = Vbuffer_alist; GC_CONSP (tail); tail = XCONS (tail)->cdr) + for (tail = Vbuffer_alist; GC_CONSP (tail); tail = XCDR (tail)) { - b = XBUFFER (XCONS (XCONS (tail)->car)->cdr); + b = XBUFFER (XCDR (XCAR (tail))); if (STRINGP (b->file_truename) && BUF_SAVE_MODIFF (b) < BUF_MODIFF (b)) { - register char *lfname; - - MAKE_LOCK_NAME (lfname, b->file_truename); - - if (current_lock_owner (0, lfname) == 2) - unlink (lfname); + unlock_file(b->file_truename); } } } @@ -690,7 +713,7 @@ unlock_buffer (buffer) unlock_file (buffer->file_truename); } -DEFUN ("file-locked-p", Ffile_locked_p, Sfile_locked_p, 0, 1, 0, +DEFUN ("file-locked-p", Ffile_locked_p, Sfile_locked_p, 1, 1, 0, "Return nil if the FILENAME is not locked,\n\ t if it is locked by you, else a string of the name of the locker.") (filename) @@ -731,6 +754,10 @@ init_filelock () void syms_of_filelock () { + DEFVAR_LISP ("temporary-file-directory", &Vtemporary_file_directory, + "The directory for writing temporary files."); + Vtemporary_file_directory = Qnil; + defsubr (&Sunlock_buffer); defsubr (&Slock_buffer); defsubr (&Sfile_locked_p);