git: e048bd5c0954 - stable/12 - elfctl: avoid touching file if no change made

[Ed Maste]

The branch stable/12 has been updated by emaste:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=e048bd5c0954814f72e04df8b7b7ff183da45a19

commit e048bd5c0954814f72e04df8b7b7ff183da45a19
Author:     Ed Maste <ema...@freebsd.org>
AuthorDate: 2021-05-25 18:25:18 +0000
Commit:     Ed Maste <ema...@freebsd.org>
CommitDate: 2021-12-12 18:58:23 +0000

    elfctl: avoid touching file if no change made
    
    Suggested by:   brooks
    Reviewed by:    brooks, markj
    MFC after:      1 week
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D30452
    
    (cherry picked from commit 3f2508b7f3855102abed99b846e30e728ba3d04d)
    (cherry picked from commit 5ceb90aa667afbd0941f045073d54aea35d40f1b)
---
 usr.bin/elfctl/elfctl.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/usr.bin/elfctl/elfctl.c b/usr.bin/elfctl/elfctl.c
index 205be39fadc7..6f23b6a94501 100644
--- a/usr.bin/elfctl/elfctl.c
+++ b/usr.bin/elfctl/elfctl.c
@@ -290,7 +290,7 @@ convert_to_feature_val(char *feature_str, uint32_t 
*feature_val)
 static bool
 edit_file_features(Elf *elf, int phcount, int fd, char *val)
 {
-       uint32_t features;
+       uint32_t features, prev_features;
        uint64_t off;
 
        if (!get_file_features(elf, phcount, fd, &features, &off)) {
@@ -298,8 +298,12 @@ edit_file_features(Elf *elf, int phcount, int fd, char 
*val)
                return (false);
        }
 
+       prev_features = features;
        if (!convert_to_feature_val(val, &features))
                return (false);
+       /* Avoid touching file if no change. */
+       if (features == prev_features)
+               return (true);
 
        if (lseek(fd, off, SEEK_SET) == -1 ||
            write(fd, &features, sizeof(features)) <