From 10d07f6813a5909bb9ae957bc7424b3ad3099b93 Mon Sep 17 00:00:00 2001
From: Andrey Rys <rys@lynxlynx.ru>
Date: Sat, 6 Apr 2019 18:49:54 +0700
Subject: [PATCH] "-O ftrunc=": implement file truncations (without sanity
 checks).

---
 VERSION     |  2 +-
 tfc_error.c |  1 +
 tfc_vars.c  |  2 +-
 tfcrypt.c   | 12 ++++++++++++
 tfcrypt.h   |  2 +-
 5 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/VERSION b/VERSION
index 7273c0f..6f4247a 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-25
+26
diff --git a/tfc_error.c b/tfc_error.c
index 11c22bb..c4e51f1 100644
--- a/tfc_error.c
+++ b/tfc_error.c
@@ -256,6 +256,7 @@ void usage(void)
 	tfc_say("    Internally this number is translated into number of %u byte blocks.", TFC_U(TF_BLOCK_SIZE));
 	tfc_say("    oseek=val: seek destination file/device by these val bytes.");
 	tfc_say("    count=val: process only these val bytes, both input and output.");
+	tfc_say("    ftrunc=val: truncate output file to these val bytes before closing it.");
 	tfc_say("    xkey=val: take only val bytes from user keyfile.");
 	tfc_say("    okey=val: seek the key before reading it (usually a device).");
 	tfc_say("    xctr=val: specify size in bytes of initial counter prepended or read.");
diff --git a/tfc_vars.c b/tfc_vars.c
index 15a0320..f629264 100644
--- a/tfc_vars.c
+++ b/tfc_vars.c
@@ -41,7 +41,7 @@ tfc_byte tmpdata[TFC_TMPSIZE];
 
 char *randsource = TFC_DEFAULT_RANDSOURCE;
 
-tfc_fsize iseek_blocks, iseek, oseek, maxlen = NOFSIZE;
+tfc_fsize iseek_blocks, iseek, oseek, maxlen = NOFSIZE, ftrunc_dfd = NOFSIZE;
 tfc_fsize total_processed_src, total_processed_dst;
 tfc_fsize delta_processed;
 tfc_fsize genrandom_nr_bytes, genzero_nr_bytes;
diff --git a/tfcrypt.c b/tfcrypt.c
index 5ed5bbf..3534bb8 100644
--- a/tfcrypt.c
+++ b/tfcrypt.c
@@ -376,6 +376,17 @@ _baddfname:
 						if (counter_opt == TFC_CTR_HEAD)
 							maxlen += TF_BLOCK_SIZE;
 					}
+					else if (!strncmp(s, "ftrunc", 6) && *(s+6) == '=') {
+						s += 7;
+						ftrunc_dfd = tfc_humanfsize(s, &stoi);
+						if (!str_empty(stoi)) {
+							ftrunc_dfd = tfc_fnamesize(s, YES);
+							ftrunc_dfd = tfc_modifysize(ftrunc_dfd, strchr(s, ':'));
+							if (ftrunc_dfd == NOFSIZE) xerror(NO, YES, YES,
+							"%s: invalid ftrunc value", s);
+						}
+						else ftrunc_dfd = tfc_modifysize(ftrunc_dfd, strchr(s, ':'));
+					}
 					else if (!strncmp(s, "xkey", 4) && *(s+4) == '=') {
 						s += 5;
 						maxkeylen = tfc_humanfsize(s, &stoi);
@@ -1277,6 +1288,7 @@ _nomac:
 
 	if (do_preserve_time) fcopy_matime(dfd, &s_stat);
 	xclose(sfd);
+	if (ftrunc_dfd != NOFSIZE) if (ftruncate(dfd, (off_t)ftrunc_dfd) == -1) xerror(YES, NO, YES, "ftruncate(%d)", dfd);
 	xclose(dfd);
 
 	xexit(exitcode);
diff --git a/tfcrypt.h b/tfcrypt.h
index f2cb89c..49073c9 100644
--- a/tfcrypt.h
+++ b/tfcrypt.h
@@ -138,7 +138,7 @@ extern tfc_byte srcblk[TFC_BLKSIZE], dstblk[TFC_BLKSIZE], *pblk;
 extern tfc_byte macvrfy[SKEIN_DIGEST_SIZE], macresult[SKEIN_DIGEST_SIZE];
 extern tfc_byte tmpdata[TFC_TMPSIZE];
 extern char *randsource;
-extern tfc_fsize iseek_blocks, iseek, oseek, maxlen;
+extern tfc_fsize iseek_blocks, iseek, oseek, maxlen, ftrunc_dfd;
 extern tfc_fsize total_processed_src, total_processed_dst;
 extern tfc_fsize delta_processed;
 extern tfc_fsize genrandom_nr_bytes, genzero_nr_bytes;
-- 
2.31.1