From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Wolfgang Bumiller <w.bumiller@proxmox.com>

Date: Mon, 6 Apr 2020 12:16:41 +0200

Subject: [PATCH] PVE: [Up] qemu-img dd: add isize parameter

for writing small images from stdin to bigger ones

In order to distinguish between an actually unexpected and

an expected end of input.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

---

 qemu-img.c | 28 +++++++++++++++++++++++++---

 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c

index f773182bd0..98a6562364 100644

--- a/qemu-img.c

+++ b/qemu-img.c

@@ -4794,11 +4794,13 @@ static int img_bitmap(int argc, char **argv)

 #define C_OF      010

 #define C_SKIP    020

 #define C_OSIZE   040

+#define C_ISIZE   0100

 struct DdInfo {

     unsigned int flags;

     int64_t count;

     int64_t osize;

+    int64_t isize;

 };

 struct DdIo {

@@ -4887,6 +4889,19 @@ static int img_dd_osize(const char *arg,

     return 0;

 }

+static int img_dd_isize(const char *arg,

+                        struct DdIo *in, struct DdIo *out,

+                        struct DdInfo *dd)

+{

+    dd->isize = cvtnum("size", arg);

+

+    if (dd->isize < 0) {

+        return 1;

+    }

+

+    return 0;

+}

+

 static int img_dd(int argc, char **argv)

 {

     int ret = 0;

@@ -4901,12 +4916,14 @@ static int img_dd(int argc, char **argv)

     int c, i;

     const char *out_fmt = "raw";

     const char *fmt = NULL;

-    int64_t size = 0;

+    int64_t size = 0, readsize = 0;

     int64_t block_count = 0, out_pos, in_pos;

     bool force_share = false;

     struct DdInfo dd = {

         .flags = 0,

         .count = 0,

+        .osize = 0,

+        .isize = -1,

     };

     struct DdIo in = {

         .bsz = 512, /* Block size is by default 512 bytes */

@@ -4928,6 +4945,7 @@ static int img_dd(int argc, char **argv)

         { "of", img_dd_of, C_OF },

         { "skip", img_dd_skip, C_SKIP },

         { "osize", img_dd_osize, C_OSIZE },

+        { "isize", img_dd_isize, C_ISIZE },

         { NULL, NULL, 0 }

     };

     const struct option long_options[] = {

@@ -5124,14 +5142,18 @@ static int img_dd(int argc, char **argv)

     in.buf = g_new(uint8_t, in.bsz);

-    for (out_pos = 0; in_pos < size; block_count++) {

+    readsize = (dd.isize > 0) ? dd.isize : size;

+    for (out_pos = 0; in_pos < readsize; block_count++) {

         int in_ret, out_ret;

-        size_t in_bsz = in_pos + in.bsz > size ? size - in_pos : in.bsz;

+        size_t in_bsz = in_pos + in.bsz > readsize ? readsize - in_pos : in.bsz;

         if (blk1) {

             in_ret = blk_pread(blk1, in_pos, in.buf, in_bsz);

         } else {

             in_ret = read(STDIN_FILENO, in.buf, in_bsz);

             if (in_ret == 0) {

+                if (dd.isize == 0) {

+                    goto out;

+                }

                 /* early EOF is considered an error */

                 error_report("Input ended unexpectedly");

                 ret = -1;