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authorTimo Teras <timo.teras@iki.fi>2009-11-06 11:31:03 +0200
committerTimo Teras <timo.teras@iki.fi>2009-11-06 11:31:03 +0200
commita93a35eecaf580d97f6a451d7e951be0ff18372c (patch)
treecec5984f85821ad8aff5cfe317e98c0e5f4ab36e /src/archive.c
parent44ac0b06af20bd32010502a10d8bb7752215c627 (diff)
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apk: add --never-overwrite flag (ref #197)
to never ever overwrite a while in the filesystem the user knows about. it gives the impression of extraction succeeding even though nothing was done. this is inteded to be used only for bootstrapping with overlay.
Diffstat (limited to 'src/archive.c')
-rw-r--r--src/archive.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/src/archive.c b/src/archive.c
index 58d2573..0ba17c5 100644
--- a/src/archive.c
+++ b/src/archive.c
@@ -339,7 +339,17 @@ int apk_archive_entry_extract(int atfd, const struct apk_file_info *ae,
fn = alloca(PATH_MAX);
snprintf(fn, PATH_MAX, "%s%s", ae->name, suffix);
}
- unlinkat(atfd, fn, 0);
+
+ if ((!S_ISDIR(ae->mode) && !S_ISREG(ae->mode)) ||
+ (ae->link_target != NULL)) {
+ /* non-standard entries need to be deleted first */
+ if (apk_flags & APK_NEVER_OVERWRITE) {
+ if (faccessat(atfd, fn, F_OK, AT_SYMLINK_NOFOLLOW) == 0)
+ return 0;
+ } else {
+ unlinkat(atfd, fn, 0);
+ }
+ }
switch (ae->mode & S_IFMT) {
case S_IFDIR:
@@ -349,8 +359,16 @@ int apk_archive_entry_extract(int atfd, const struct apk_file_info *ae,
break;
case S_IFREG:
if (ae->link_target == NULL) {
- fd = openat(atfd, fn, O_RDWR | O_CREAT, ae->mode & 07777);
+ int flags = O_RDWR | O_CREAT | O_TRUNC;
+
+ if (apk_flags & APK_NEVER_OVERWRITE)
+ flags |= O_EXCL;
+
+ fd = openat(atfd, fn, flags, ae->mode & 07777);
if (fd < 0) {
+ if ((apk_flags & APK_NEVER_OVERWRITE) &&
+ (errno == EEXIST))
+ return 0;
r = -1;
break;
}