[hackers] [sbase] tail: Use fstat in case file is removed || Michael Forney

[git]

commit 1ab4ac60ff891ee4dcd0ca729e9f897c4f4a1f42
Author:     Michael Forney <mfor...@mforney.org>
AuthorDate: Mon Jul 3 14:58:51 2017 -0700
Commit:     Anselm R Garbe <garb...@gmail.com>
CommitDate: Fri Jul 14 07:50:52 2017 +0200

    tail: Use fstat in case file is removed

diff --git a/tail.c b/tail.c
index 1ab9d18..ce65a01 100644
--- a/tail.c
+++ b/tail.c
@@ -175,8 +175,8 @@ main(int argc, char *argv[])
                        }
                        if (many)
                                printf("%s==> %s <==\n", newline ? "\n" : "", 
*argv);
-                       if (stat(*argv, &st1) < 0)
-                               eprintf("stat %s:", *argv);
+                       if (fstat(fd, &st1) < 0)
+                               eprintf("fstat %s:", *argv);
                        if (!(S_ISFIFO(st1.st_mode) || S_ISREG(st1.st_mode)))
                                fflag = 0;
                        newline = 1;
@@ -193,16 +193,14 @@ main(int argc, char *argv[])
                        for (;;) {
                                if (concat(fd, *argv, 1, "<stdout>") < 0)
                                        exit(1);
-                               /* ignore error in case file was removed, we 
continue
-                                * tracking the existing open file descriptor */
-                               if (!stat(*argv, &st2)) {
-                                       if (st2.st_size < st1.st_size) {
-                                               fprintf(stderr, "%s: file 
truncated\n", *argv);
-                                               if (lseek(fd, SEEK_SET, 0) < 0)
-                                                       eprintf("lseek:");
-                                       }
-                                       st1 = st2;
+                               if (fstat(fd, &st2) < 0)
+                                       eprintf("fstat %s:", *argv);
+                               if (st2.st_size < st1.st_size) {
+                                       fprintf(stderr, "%s: file truncated\n", 
*argv);
+                                       if (lseek(fd, SEEK_SET, 0) < 0)
+                                               eprintf("lseek:");
                                }
+                               st1 = st2;
                                sleep(1);
                        }
                }