Support mtime/atime/ctime extended headers in !SMALL builds.

These are becoming quite common in distributed software (including
tars produced by Python and Go) and often standard timestamps are
not set, resulting in extracted files dated as the epoch.

Lots of help from tb@, ok tb@ millert@

diff --git a/bin/pax/tar.c b/bin/pax/tar.c
index 9d8a92d..686ec52 100644 (file)
--- a/bin/pax/tar.c
+++ b/bin/pax/tar.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: tar.c,v 1.69 2021/06/14 00:36:13 deraadt Exp $        */
+/*     $OpenBSD: tar.c,v 1.70 2022/03/01 21:19:11 sthen Exp $  */
 /*     $NetBSD: tar.c,v 1.5 1995/03/21 09:07:49 cgd Exp $      */
 
 /*-
@@ -415,6 +415,7 @@ tar_rd(ARCHD *arcn, char *buf)
        else
                arcn->sb.st_mtime = val;
        arcn->sb.st_ctime = arcn->sb.st_atime = arcn->sb.st_mtime;
+       arcn->sb.st_ctimensec = arcn->sb.st_atimensec = arcn->sb.st_mtimensec;
 
        /*
         * have to look at the last character, it may be a '/' and that is used
@@ -784,12 +785,21 @@ reset:
        arcn->sb.st_mode = (mode_t)(asc_ul(hd->mode, sizeof(hd->mode), OCT) &
            0xfff);
        arcn->sb.st_size = (off_t)asc_ull(hd->size, sizeof(hd->size), OCT);
-       val = asc_ull(hd->mtime, sizeof(hd->mtime), OCT);
-       if (val > MAX_TIME_T)
-               arcn->sb.st_mtime = INT_MAX;                    /* XXX 2038 */
-       else
-               arcn->sb.st_mtime = val;
-       arcn->sb.st_ctime = arcn->sb.st_atime = arcn->sb.st_mtime;
+       if (arcn->sb.st_mtime == 0) {
+               val = asc_ull(hd->mtime, sizeof(hd->mtime), OCT);
+               if (val > MAX_TIME_T)
+                       arcn->sb.st_mtime = INT_MAX;            /* XXX 2038 */
+               else
+                       arcn->sb.st_mtime = val;
+       }
+       if (arcn->sb.st_ctime == 0) {
+               arcn->sb.st_ctime = arcn->sb.st_mtime;
+               arcn->sb.st_ctimensec = arcn->sb.st_mtimensec;
+       }
+       if (arcn->sb.st_atime == 0) {
+               arcn->sb.st_atime = arcn->sb.st_mtime;
+               arcn->sb.st_atimensec = arcn->sb.st_mtimensec;
+       }
 
        /*
         * If we can find the ascii names for gname and uname in the password
@@ -1191,6 +1201,40 @@ expandname(char *buf, size_t len, char **gnu_name, const char *name,
 /* longest record we'll accept */
 #define MAXXHDRSZ      BLKMULT
 
+static int
+rd_time(struct timespec *ts, const char *keyword, char *p)
+{
+       const char *errstr;
+       char *q;
+       int multiplier;
+
+       if ((q = strchr(p, '.')) != NULL)
+               *q = '\0';
+
+       ts->tv_sec = strtonum(p, 0, MAX_TIME_T, &errstr);
+       if (errstr != NULL) {
+               paxwarn(1, "%s is %s: %s", keyword, errstr, p);
+               return -1;
+       }
+
+       ts->tv_nsec = 0;
+
+       if (q == NULL)
+               return 0;
+
+       multiplier = 100000000;
+       for (q++; *q != '\0'; q++) {
+               if (!isdigit((unsigned char)*q)) {
+                       paxwarn(1, "%s contains non-digit", keyword);
+                       return -1;
+               }
+               ts->tv_nsec += (*q - '0') * multiplier;
+               multiplier /= 10;
+       }
+
+       return 0;
+}
+
 static int
 rd_xheader(ARCHD *arcn, int global, off_t size)
 {
@@ -1269,6 +1313,18 @@ rd_xheader(ARCHD *arcn, int global, off_t size)
                        } else if (!strcmp(keyword, "linkpath")) {
                                arcn->ln_nlen = strlcpy(arcn->ln_name, p,
                                    sizeof(arcn->ln_name));
+                       } else if (!strcmp(keyword, "mtime")) {
+                               ret = rd_time(&arcn->sb.st_mtim, keyword, p);
+                               if (ret < 0)
+                                       break;
+                       } else if (!strcmp(keyword, "atime")) {
+                               ret = rd_time(&arcn->sb.st_atim, keyword, p);
+                               if (ret < 0)
+                                       break;
+                       } else if (!strcmp(keyword, "ctime")) {
+                               ret = rd_time(&arcn->sb.st_ctim, keyword, p);
+                               if (ret < 0)
+                                       break;
                        }
                }
                p = nextp;