diff options
Diffstat (limited to 'tar')
| -rw-r--r-- | tar/bsdtar.1 | 27 | ||||
| -rw-r--r-- | tar/bsdtar.c | 6 | ||||
| -rw-r--r-- | tar/bsdtar.h | 2 | ||||
| -rw-r--r-- | tar/cmdline.c | 2 |
4 files changed, 37 insertions, 0 deletions
diff --git a/tar/bsdtar.1 b/tar/bsdtar.1 index 04b56553..723ea38f 100644 --- a/tar/bsdtar.1 +++ b/tar/bsdtar.1 @@ -469,6 +469,13 @@ This is the reverse of and the default behavior if .Nm is run as non-root in x mode. +.It Fl Fl no-safe-writes +(x mode only) +Do not create temporary files and use +.Xr rename 2 +to replace the original ones. +This is the reverse of +.Fl Fl safe-writes . .It Fl Fl no-same-owner (x mode only) Do not extract owner and group IDs. @@ -756,6 +763,26 @@ The default is .Ar hrs which applies substitutions to all names. In particular, it is never necessary to specify h, r, or s. +.It Fl Fl safe-writes +(x mode only) +Extract files atomically. +By default +.Nm +unlinks the original file with the same name as the extracted file (if it +exists), and then creates it immediately under the same name and writes to +it. +For a short period of time, applications trying to access the file might +not find it, or see incomplete results. +If +.Fl Fl safe-writes +is enabled, +.Nm +first creates a unique temporary file, then writes the new contents to +the temporary file, and finally renames the temporary file to its final +name atomically using +.Xr rename 2 . +This guarantees that an application accessing the file, will either see +the old contents or the new contents at all times. .It Fl Fl same-owner (x mode only) Extract owner and group IDs. diff --git a/tar/bsdtar.c b/tar/bsdtar.c index b59963d0..af41be5e 100644 --- a/tar/bsdtar.c +++ b/tar/bsdtar.c @@ -542,6 +542,9 @@ main(int argc, char **argv) bsdtar->extract_flags &= ~ARCHIVE_EXTRACT_MAC_METADATA; bsdtar->flags |= OPTFLAG_NO_MAC_METADATA; break; + case OPTION_NO_SAFE_WRITES: + bsdtar->extract_flags &= ~ARCHIVE_EXTRACT_SAFE_WRITES; + break; case OPTION_NO_SAME_OWNER: /* GNU tar */ bsdtar->extract_flags &= ~ARCHIVE_EXTRACT_OWNER; break; @@ -658,6 +661,9 @@ main(int argc, char **argv) usage(); #endif break; + case OPTION_SAFE_WRITES: + bsdtar->extract_flags |= ARCHIVE_EXTRACT_SAFE_WRITES; + break; case OPTION_SAME_OWNER: /* GNU tar */ bsdtar->extract_flags |= ARCHIVE_EXTRACT_OWNER; break; diff --git a/tar/bsdtar.h b/tar/bsdtar.h index c9206dfd..89aa3aa9 100644 --- a/tar/bsdtar.h +++ b/tar/bsdtar.h @@ -164,6 +164,7 @@ enum { OPTION_NO_ACLS, OPTION_NO_FFLAGS, OPTION_NO_MAC_METADATA, + OPTION_NO_SAFE_WRITES, OPTION_NO_SAME_OWNER, OPTION_NO_SAME_PERMISSIONS, OPTION_NO_XATTRS, @@ -177,6 +178,7 @@ enum { OPTION_OPTIONS, OPTION_PASSPHRASE, OPTION_POSIX, + OPTION_SAFE_WRITES, OPTION_SAME_OWNER, OPTION_STRIP_COMPONENTS, OPTION_TOTALS, diff --git a/tar/cmdline.c b/tar/cmdline.c index 21558e12..b80937ff 100644 --- a/tar/cmdline.c +++ b/tar/cmdline.c @@ -123,6 +123,7 @@ static const struct bsdtar_option { { "no-fflags", 0, OPTION_NO_FFLAGS }, { "no-mac-metadata", 0, OPTION_NO_MAC_METADATA }, { "no-recursion", 0, 'n' }, + { "no-safe-writes", 0, OPTION_NO_SAFE_WRITES }, { "no-same-owner", 0, OPTION_NO_SAME_OWNER }, { "no-same-permissions", 0, OPTION_NO_SAME_PERMISSIONS }, { "no-xattr", 0, OPTION_NO_XATTRS }, @@ -144,6 +145,7 @@ static const struct bsdtar_option { { "posix", 0, OPTION_POSIX }, { "preserve-permissions", 0, 'p' }, { "read-full-blocks", 0, 'B' }, + { "safe-writes", 0, OPTION_SAFE_WRITES }, { "same-owner", 0, OPTION_SAME_OWNER }, { "same-permissions", 0, 'p' }, { "strip-components", 1, OPTION_STRIP_COMPONENTS }, |