[dev] [sbase] [PATCH 3/4] tar: Implement -m flag

[Michael Forney]

This changes the default behavior to adjust mtimes to what is present in
the file header.
---
 tar.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/tar.c b/tar.c
index 7bd709d..47d2334 100644
--- a/tar.c
+++ b/tar.c
@@ -2,9 +2,11 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <stdio.h>
+#include <stdbool.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/time.h>
 #include <limits.h>
 #include <grp.h>
 #include <pwd.h>
@@ -49,13 +51,15 @@ static FILE *tarfile;
 static ino_t tarinode;
 static dev_t tardev;
 
+static bool mflag = false;
+
 static void
 usage(void)
 {
-       eprintf("usage: tar [-f tarfile] [-C dir] [-]x|t\n"
+       eprintf("usage: tar [-f tarfile] [-C dir] [-]x[m]|t\n"
                "       tar [-f tarfile] [-C dir] [-]c dir\n"
                "       tar [-C dir] cf tarfile dir\n"
-               "       tar [-C dir] x|tf tarfile\n");
+               "       tar [-C dir] x[m]|tf tarfile\n");
 }
 
 int
@@ -79,6 +83,9 @@ main(int argc, char *argv[])
        case 'f':
                file = EARGF(usage());
                break;
+       case 'm':
+               mflag = true;
+               break;
        default:
                usage();
        } ARGEND;
@@ -108,6 +115,9 @@ main(int argc, char *argv[])
                                argc--, argv++;
                                dir = argv[0];
                                break;
+                       case 'm':
+                               mflag = true;
+                               break;
                        default:
                                usage();
                        }
@@ -224,9 +234,12 @@ unarchive(char *fname, int l, char b[Blksiz])
 {
        char lname[101];
        FILE *f = NULL;
-       unsigned long  mode, major, minor, type;
+       unsigned long  mode, major, minor, type, mtime;
+       struct timeval times[2] = {0};
        Header *h = (void*)b;
 
+       if(!mflag)
+               mtime = strtoul(h->mtime, 0, 8);
        unlink(fname);
        switch(h->type) {
        case REG:
@@ -276,6 +289,12 @@ unarchive(char *fname, int l, char b[Blksiz])
        }
        if(f)
                fclose(f);
+
+       if(!mflag) {
+               times[0].tv_sec = times[1].tv_sec = mtime;
+               if(utimes(fname, times))
+                       perror(fname);
+       }
        return 0;
 }
 
-- 
2.1.3.1.g339ec9c