create new file and rename

diff --git a/authfile.c b/authfile.c
index abf31fb8f91ff665823e67395fe9eb26043a078c..8c023d1e8e3a8a0ddd422082d96c5288e69dabec 100644 (file)
--- a/authfile.c
+++ b/authfile.c
@@ -4,6 +4,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <pwd.h>
+#include <time.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -109,7 +110,7 @@ struct _auth_obj authfile(const char *tokenid,
        struct _auth_obj ret = {0};
        mode_t oldmask;
        FILE *fp = NULL;
-       char *fn;
+       char *fn, *nfn;
        int fnl;
        char *buf = NULL;
        struct {
@@ -130,6 +131,8 @@ struct _auth_obj authfile(const char *tokenid,
        }
        fn = alloca(fnl);
        make_path(fn, tokenid, userid);
+       nfn = alloca(fnl+32);
+       snprintf(nfn, fnl+32, "%s.%d.%ld", fn, (int)getpid(), (long)time(NULL));
        fp = fopen(fn, "r");
        if (fp) {
                struct stat st;
@@ -187,7 +190,7 @@ struct _auth_obj authfile(const char *tokenid,
        }
 
        oldmask = umask(077);
-       if ((fp = fopen(fn, "w"))) {
+       if ((fp = fopen(nfn, "w"))) {
                int i;
 
                if (fprintf(fp, "%s:%s:%s:", tokenid?tokenid:w.tokenid,
@@ -205,6 +208,11 @@ struct _auth_obj authfile(const char *tokenid,
                ret.err = strerror(errno);
        }
        (void)umask(oldmask);
+       if (ret.err) {
+               unlink(nfn); /* may not exist but no matter */
+       } else if (rename(nfn, fn)) {
+               ret.err = strerror(errno);
+       }
 
        if (!ret.err) {
                int bufsize = (w.userid?strlen(w.userid)+1:0) + ao.paylsize;