mv, cp: Preserve nanosecond timestamps

Otherwise, we run into problems in a typical autoconf-based build
system:

  - config.status is created at some point between two seconds.
  - config.status is run, generating Makefile by first writing to a file
    in /tmp, and then mv-ing it to Makefile.
  - If this mv happens before the beginning of the next second, Makefile
    will be created with the same tv_sec as config.status, but with
    tv_nsec = 0.
  - When make runs, it sees that Makefile is older than config.status,
    and re-runs config.status to generate Makefile.
This commit is contained in:
Michael Forney 2015-05-16 04:57:25 +00:00 committed by sin
parent 0ba81a0f84
commit 1d28fbd6cf

View File

@ -30,7 +30,7 @@ cp(const char *s1, const char *s2, int depth)
FILE *f1, *f2; FILE *f1, *f2;
struct dirent *d; struct dirent *d;
struct stat st; struct stat st;
struct utimbuf ut; struct timespec times[2];
ssize_t r; ssize_t r;
int (*statf)(const char *, struct stat *); int (*statf)(const char *, struct stat *);
char target[PATH_MAX], ns1[PATH_MAX], ns2[PATH_MAX], *statf_name; char target[PATH_MAX], ns1[PATH_MAX], ns2[PATH_MAX], *statf_name;
@ -154,9 +154,9 @@ cp(const char *s1, const char *s2, int depth)
if (cp_aflag || cp_pflag) { if (cp_aflag || cp_pflag) {
/* timestamp and owner*/ /* timestamp and owner*/
if (!S_ISLNK(st.st_mode)) { if (!S_ISLNK(st.st_mode)) {
ut.actime = st.st_atime; times[0] = st.st_atim;
ut.modtime = st.st_mtime; times[1] = st.st_mtim;
utime(s2, &ut); utimensat(AT_FDCWD, s2, times, 0);
if (chown(s2, st.st_uid, st.st_gid) < 0) { if (chown(s2, st.st_uid, st.st_gid) < 0) {
weprintf("chown %s:", s2); weprintf("chown %s:", s2);