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Negotation env lists can specify "client & server"

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This commit is contained in:
Wayne Davison
2020-06-26 16:51:30 -07:00
parent d07c2992d1
commit ab29ee9c44
4 changed files with 69 additions and 37 deletions
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3
NEWS.md
View File

@@ -17,7 +17,8 @@ Protocol: 31 (unchanged)
### ENHANCEMENTS:
- Allow the server side to restrict checksum & compression choices via
the same environment variables the client uses.
the same environment variables the client uses. Allow the env vars
to be divided into "client list & server list" by the "`&`" char.
- Simplify how the negotiation environment variables apply to older rsync
versions.

8
batch.c
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@@ -269,14 +269,6 @@ void write_batch_shell_file(void)
err |= write_opt("--exclude-from", "-");
}
/* We need to make sure that any protocol-based or negotiated choices get accurately
* reflected in the options we save AND that we avoid any need for --read-batch to
* do a string-based negotiation (since we don't write them into the file). */
if (do_compression)
err |= write_opt("--compress-choice", compress_choice);
if (strchr(checksum_choice, ',') || xfersum_type != parse_csum_name(NULL, -1))
err |= write_opt("--checksum-choice", checksum_choice);
/* Elide the filename args from the option list, but scan for them in reverse. */
for (i = raw_argc-1, j = cooked_argc-1; i > 0 && j >= 0; i--) {
if (strcmp(raw_argv[i], cooked_argv[j]) == 0) {

76
compat.c
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@@ -20,6 +20,7 @@
*/
#include "rsync.h"
#include "itypes.h"
extern int am_server;
extern int am_sender;
@@ -109,6 +110,9 @@ struct name_num_obj valid_compressions = {
#define CF_INPLACE_PARTIAL_DIR (1<<6)
#define CF_VARINT_FLIST_FLAGS (1<<7)
#define ENV_CHECKSUM 0
#define ENV_COMPRESS 1
static const char *client_info;
/* The server makes sure that if either side only supports a pre-release
@@ -262,10 +266,14 @@ static void init_nno_saw(struct name_num_obj *nno, int val)
static int parse_nni_str(struct name_num_obj *nno, const char *from, char *tobuf, int tobuf_len)
{
char *to = tobuf, *tok = NULL;
int cnt = 0;
int saw_tok = 0, cnt = 0;
while (1) {
if (*from == ' ' || !*from) {
int at_space = isSpace(from);
char ch = *from++;
if (ch == '&')
ch = '\0';
if (!ch || at_space) {
if (tok) {
struct name_num_item *nni = get_nni_by_name(nno, tok, to - tok);
if (nni && !nno->saw[nni->num]) {
@@ -279,9 +287,10 @@ static int parse_nni_str(struct name_num_obj *nno, const char *from, char *tobuf
}
} else
to = tok - (tok != tobuf);
saw_tok = 1;
tok = NULL;
}
if (!*from++)
if (!ch)
break;
continue;
}
@@ -294,10 +303,13 @@ static int parse_nni_str(struct name_num_obj *nno, const char *from, char *tobuf
to = tok - (tok != tobuf);
break;
}
*to++ = *from++;
*to++ = ch;
}
*to = '\0';
if (saw_tok && to == tobuf)
return strlcpy(tobuf, "INVALID", MAX_NSTR_STRLEN);
return to - tobuf;
}
@@ -349,14 +361,36 @@ static void recv_negotiate_str(int f_in, struct name_num_obj *nno, char *tmpbuf,
exit_cleanup(RERR_UNSUPPORTED);
}
static const char *getenv_nstr(int etype)
{
const char *env_str = getenv(etype == ENV_COMPRESS ? "RSYNC_COMPRESS_LIST" : "RSYNC_CHECKSUM_LIST");
/* When writing a batch file, we always negotiate an old-style choice. */
if (write_batch)
env_str = etype == ENV_COMPRESS ? "zlib" : protocol_version >= 30 ? "md5" : "md4";
if (am_server && env_str) {
char *cp = strchr(env_str, '&');
if (cp)
env_str = cp + 1;
}
return env_str;
}
/* If num2 < 0 then the caller is checking compress values, otherwise checksum values. */
void validate_choice_vs_env(int num1, int num2)
{
struct name_num_obj *nno = num2 < 0 ? &valid_compressions : &valid_checksums;
const char *list_str = getenv(num2 < 0 ? "RSYNC_COMPRESS_LIST" : "RSYNC_CHECKSUM_LIST");
const char *list_str = getenv_nstr(num2 < 0 ? ENV_COMPRESS : ENV_CHECKSUM);
char tmpbuf[MAX_NSTR_STRLEN];
if (!list_str || !*list_str)
if (!list_str)
return;
while (isSpace(list_str)) list_str++;
if (!*list_str)
return;
init_nno_saw(nno, 0);
@@ -422,17 +456,15 @@ int get_default_nno_list(struct name_num_obj *nno, char *to_buf, int to_buf_len,
return len;
}
static void send_negotiate_str(int f_out, struct name_num_obj *nno, const char *env_name)
static void send_negotiate_str(int f_out, struct name_num_obj *nno, int etype)
{
char tmpbuf[MAX_NSTR_STRLEN];
const char *list_str = getenv(env_name);
const char *list_str = getenv_nstr(etype);
int len;
if (list_str && *list_str) {
init_nno_saw(nno, 0);
len = parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
if (!len)
len = strlcpy(tmpbuf, "FAIL", MAX_NSTR_STRLEN);
list_str = tmpbuf;
} else
list_str = NULL;
@@ -447,15 +479,10 @@ static void send_negotiate_str(int f_out, struct name_num_obj *nno, const char *
rprintf(FINFO, "Client %s list (on client): %s\n", nno->type, tmpbuf);
}
if (local_server) {
/* A local server doesn't bother to send/recv the strings, it just constructs
* and parses the same string on both sides. */
recv_negotiate_str(-1, nno, tmpbuf, len);
} else if (do_negotiated_strings) {
/* Each side sends their list of valid names to the other side and then both sides
* pick the first name in the client's list that is also in the server's list. */
/* Each side sends their list of valid names to the other side and then both sides
* pick the first name in the client's list that is also in the server's list. */
if (do_negotiated_strings)
write_vstring(f_out, tmpbuf, len);
}
}
static void negotiate_the_strings(int f_in, int f_out)
@@ -463,10 +490,10 @@ static void negotiate_the_strings(int f_in, int f_out)
/* We send all the negotiation strings before we start to read them to help avoid a slow startup. */
if (!checksum_choice)
send_negotiate_str(f_out, &valid_checksums, "RSYNC_CHECKSUM_LIST");
send_negotiate_str(f_out, &valid_checksums, ENV_CHECKSUM);
if (do_compression && !compress_choice)
send_negotiate_str(f_out, &valid_compressions, "RSYNC_COMPRESS_LIST");
send_negotiate_str(f_out, &valid_compressions, ENV_COMPRESS);
if (valid_checksums.saw) {
char tmpbuf[MAX_NSTR_STRLEN];
@@ -645,10 +672,8 @@ void setup_protocol(int f_out,int f_in)
if (local_server || strchr(client_info, 'I') != NULL)
compat_flags |= CF_INPLACE_PARTIAL_DIR;
if (local_server || strchr(client_info, 'v') != NULL) {
if (!write_batch || protocol_version >= 30) {
do_negotiated_strings = 1;
compat_flags |= CF_VARINT_FLIST_FLAGS;
}
do_negotiated_strings = 1;
compat_flags |= CF_VARINT_FLIST_FLAGS;
}
if (strchr(client_info, 'V') != NULL) { /* Support a pre-release 'V' that got superseded */
if (!write_batch)
@@ -697,6 +722,9 @@ void setup_protocol(int f_out,int f_in)
#endif
}
if (read_batch)
do_negotiated_strings = 0;
if (need_unsorted_flist && (!am_sender || inc_recurse))
unsort_ndx = ++file_extra_cnt;

19
rsync.1.md
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@@ -1506,7 +1506,10 @@ your home directory (remove the '=' for that).
transfer checksum separately from the pre-transfer checksum, and it ignores
"auto" and all unknown checksum names. If the remote rsync is not new
enough to handle a checksum negotiation list, its list is assumed to
consist of a single "md5" or "md4" item based on the protocol version.
consist of a single "md5" or "md4" item based on the protocol version. If
the environment variable contains a "`&`" character, the string is
separated into the client list & server list, either one of which can be
empty (giving that side the default list).
The use of the `--checksum-choice` option overrides this environment list.
@@ -2295,11 +2298,14 @@ your home directory (remove the '=' for that).
When both sides of the transfer are at least 3.2.0, rsync chooses the first
algorithm in the client's list of choices that is also in the server's list
of choices. Your default order can be customized by setting the environment
of choices. The default order can be customized by setting the environment
variable RSYNC_COMPRESS_LIST to a space-separated list of acceptable
compression names. If no common compress choice is found, the client exits
with an error. If the remote rsync is too old to support checksum negotiation,
its list is assumed to be "zlib".
with an error. If the remote rsync is too old to support checksum
negotiation, its list is assumed to be "zlib". If the environment variable
contains a "`&`" character, the string is separated into the client list &
server list, either one of which can be empty (giving that side the default
list).
There are some older rsync versions that were configured to reject a `-z`
option and require the use of `-zz` because their compression library was
@@ -3104,6 +3110,11 @@ your home directory (remove the '=' for that).
with `--read-batch`. See the "BATCH MODE" section for details, and also
the `--only-write-batch` option.
This option overrides the negotiated checksum & compress lists and always
negotiates a choice based on old-school md5/md4/zlib choices. If you want
a more modern choice, use the `--checksum-choice` (`--cc`) and/or
`--compress-choice` (`--zc`) options.
0. `--only-write-batch=FILE`
Works like `--write-batch`, except that no updates are made on the