Teach patch that a file dated 1969-12-31 means doesn't exist, and to fail

if a create isn't exclusive.

diff --git a/toys/patch.c b/toys/patch.c
index 612b572..10615e3 100644 (file)
--- a/toys/patch.c
+++ b/toys/patch.c
@@ -40,7 +40,8 @@ config PATCH
          a file when all all hunks to that file apply.  Patch prints failed
          hunks to stderr, and exits with nonzero status if any hunks fail.
 
-         A file compared against /dev/null is created/deleted as appropriate.
+         A file compared against /dev/null (or with a date in 1969) is
+         created/deleted as appropriate.
 */
 
 #include "toys.h"
@@ -211,9 +212,12 @@ void patch_main(void)
                        // Trim date from end of filename (if any).  We don't care.
                        for (s = patchline+4; *s && *s!='\t'; s++)
                                if (*s=='\\' && s[1]) s++;
-                       *s = 0;
-
-                       TT.oldname = xstrdup(patchline+4);
+                       if (!strncmp(s, "\t1969-12-31", 10))
+                               TT.oldname = xstrdup("/dev/null");
+                       else {
+                               *s = 0;
+                               TT.oldname = xstrdup(patchline+4);
+                       }
                } else if (!strncmp("+++ ", patchline, 4)) {
                        int i = 0, del = 0;
                        char *s, *start;
@@ -221,13 +225,12 @@ void patch_main(void)
                        finish_oldfile();
 
                        // Trim date from end of filename (if any).  We don't care.
-                       for (s = patchline+4; *s && *s!='\t'; s++)
+                       for (s = start = patchline+4; *s && *s!='\t'; s++)
                                if (*s=='\\' && s[1]) s++;
+                       if (!strncmp(s, "\t1969-12-31", 10)) start = "/dev/null";
                        *s = 0;
 
-
                        // If new file is /dev/null (before -p), we're deleting oldname
-                       start = patchline+4;
                        if (!strcmp(start, "/dev/null")) {
                                start = TT.oldname;
                                del++;
@@ -254,7 +257,7 @@ void patch_main(void)
                                                xmkpath(start, -1);
                                                *s = '/';
                                        }
-                                       TT.filein = xcreate(start, O_CREAT|O_RDWR, 0666);
+                                       TT.filein = xcreate(start, O_CREAT|O_EXCL|O_RDWR, 0666);
                                } else {
                                        printf("patching %s\n", start);
                                        TT.filein = xopen(start, O_RDWR);