As some issues that can happen with a Git client can be operating system
specific, it can be useful for a server to know which OS a client is
using. In the same way it can be useful for a client to know which OS
a server is using.
Our current agent capability is in the form of "package/version" (e.g.,
"git/1.8.3.1"). Let's extend it to include the operating system name (os)
i.e in the form "package/version-os" (e.g., "git/1.8.3.1-Linux").
Including OS details in the agent capability simplifies implementation,
maintains backward compatibility, avoids introducing a new capability,
encourages adoption across Git-compatible software, and enhances
debugging by providing complete environment information without affecting
functionality. The operating system name is retrieved using the 'sysname'
field of the `uname(2)` system call or its equivalent.
However, there are differences between `uname(1)` (command-line utility)
and `uname(2)` (system call) outputs on Windows. These discrepancies
complicate testing on Windows platforms. For example:
- `uname(1)` output: MINGW64_NT-10.0-20348.3.4.10-87d57229.x86_64\
.2024-02-14.20:17.UTC.x86_64
- `uname(2)` output: Windows.10.0.20348
On Windows, uname(2) is not actually system-supplied but is instead
already faked up by Git itself. We could have overcome the test issue
on Windows by implementing a new `uname` subcommand in `test-tool`
using uname(2), but except uname(2), which would be tested against
itself, there would be nothing platform specific, so it's just simpler
to disable the tests on Windows.
Mentored-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
Signed-off-by: Usman Akinyemi <usmanakinyemi202@xxxxxxxxx>
---
Documentation/gitprotocol-v2.txt | 13 ++++++++-----
connect.c | 2 +-
t/t5701-git-serve.sh | 16 +++++++++++++++-
t/test-lib-functions.sh | 8 ++++++++
version.c | 29 ++++++++++++++++++++++++++++-
version.h | 3 +++
6 files changed, 63 insertions(+), 8 deletions(-)
diff --git a/Documentation/gitprotocol-v2.txt b/Documentation/gitprotocol-v2.txt
index 1652fef3ae..ce4a4e5e3b 100644
--- a/Documentation/gitprotocol-v2.txt
+++ b/Documentation/gitprotocol-v2.txt
@@ -184,11 +184,14 @@ form `agent=X`) to notify the client that the server is running version
the `agent` capability with a value `Y` (in the form `agent=Y`) in its
request to the server (but it MUST NOT do so if the server did not
advertise the agent capability). The `X` and `Y` strings may contain any
-printable ASCII characters except space (i.e., the byte range 32 < x <
-127), and are typically of the form "package/version" (e.g.,
-"git/1.8.3.1"). The agent strings are purely informative for statistics
-and debugging purposes, and MUST NOT be used to programmatically assume
-the presence or absence of particular features.
+printable ASCII characters (i.e., the byte range 33 <= x <= 126), and are
+typically of the form "package/version-os" (e.g., "git/1.8.3.1-Linux")
+where `os` is the operating system name (e.g., "Linux"). `X` and `Y` can
+be configured using the GIT_USER_AGENT environment variable and it takes
+priority. The `os` is retrieved using the 'sysname' field of the `uname(2)`
+system call or its equivalent. The agent strings are purely informative for
+statistics and debugging purposes, and MUST NOT be used to programmatically
+assume the presence or absence of particular features.
ls-refs
~~~~~~~
diff --git a/connect.c b/connect.c
index 10fad43e98..4d85479075 100644
--- a/connect.c
+++ b/connect.c
@@ -625,7 +625,7 @@ const char *parse_feature_value(const char *feature_list, const char *feature, s
*offset = found + len - orig_start;
return value;
}
- /* feature with a value (e.g., "agent=git/1.2.3") */
+ /* feature with a value (e.g., "agent=git/1.2.3-Linux") */
else if (*value == '=') {
size_t end;
diff --git a/t/t5701-git-serve.sh b/t/t5701-git-serve.sh
index 4c24a188b9..678a346ed0 100755
--- a/t/t5701-git-serve.sh
+++ b/t/t5701-git-serve.sh
@@ -8,13 +8,19 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
. ./test-lib.sh
test_expect_success 'setup to generate files with expected content' '
- printf "agent=git/%s\n" "$(git version | cut -d" " -f3)" >agent_capability &&
+ printf "agent=git/%s" "$(git version | cut -d" " -f3)" >agent_capability &&
test_oid_cache <<-EOF &&
wrong_algo sha1:sha256
wrong_algo sha256:sha1
EOF
+ if test_have_prereq WINDOWS
+ then
+ printf "agent=FAKE\n" >agent_capability
+ else
+ printf -- "-%s\n" $(uname -s | test_redact_non_printables) >>agent_capability
+ fi &&
cat >expect.base <<-EOF &&
version 2
$(cat agent_capability)
@@ -31,6 +37,10 @@ test_expect_success 'setup to generate files with expected content' '
test_expect_success 'test capability advertisement' '
cat expect.base expect.trailer >expect &&
+ if test_have_prereq WINDOWS
+ then
+ GIT_USER_AGENT=FAKE && export GIT_USER_AGENT
+ fi &&
GIT_TEST_SIDEBAND_ALL=0 test-tool serve-v2 \
--advertise-capabilities >out &&
test-tool pkt-line unpack <out >actual &&
@@ -361,6 +371,10 @@ test_expect_success 'test capability advertisement with uploadpack.advertiseBund
expect.extra \
expect.trailer >expect &&
+ if test_have_prereq WINDOWS
+ then
+ GIT_USER_AGENT=FAKE && export GIT_USER_AGENT
+ fi &&
GIT_TEST_SIDEBAND_ALL=0 test-tool serve-v2 \
--advertise-capabilities >out &&
test-tool pkt-line unpack <out >actual &&
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 78e054ab50..3465904323 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -2007,3 +2007,11 @@ test_trailing_hash () {
test-tool hexdump |
sed "s/ //g"
}
+
+# Trim and replace each character with ascii code below 32 or above
+# 127 (included) using a dot '.' character.
+# Octal intervals \001-\040 and \177-\377
+# correspond to decimal intervals 1-32 and 127-255
+test_redact_non_printables () {
+ tr -d "\n\r" | tr "[\001-\040][\177-\377]" "."
+}
diff --git a/version.c b/version.c
index d95221a72a..8e927cf1eb 100644
--- a/version.c
+++ b/version.c
@@ -1,8 +1,9 @@
+#define USE_THE_REPOSITORY_VARIABLE
+
#include "git-compat-util.h"
#include "version.h"
#include "version-def.h"
#include "strbuf.h"
-#include "sane-ctype.h"
#include "gettext.h"
const char git_version_string[] = GIT_VERSION;
@@ -34,6 +35,27 @@ const char *git_user_agent(void)
return agent;
}
+/*
+ Retrieve, sanitize and cache operating system info for subsequent
+ calls. Return a pointer to the sanitized operating system info
+ string.
+*/
+static const char *os_info(void)
+{
+ static const char *os = NULL;
+
+ if (!os) {
+ struct strbuf buf = STRBUF_INIT;
+
+ get_uname_info(&buf, 0);
+ /* Sanitize the os information immediately */
+ redact_non_printables(&buf);
+ os = strbuf_detach(&buf, NULL);
+ }
+
+ return os;
+}
+
const char *git_user_agent_sanitized(void)
{
static const char *agent = NULL;
@@ -42,6 +64,11 @@ const char *git_user_agent_sanitized(void)
struct strbuf buf = STRBUF_INIT;
strbuf_addstr(&buf, git_user_agent());
+
+ if (!getenv("GIT_USER_AGENT")) {
+ strbuf_addch(&buf, '-');
+ strbuf_addstr(&buf, os_info());
+ }
redact_non_printables(&buf);
agent = strbuf_detach(&buf, NULL);
}
diff --git a/version.h b/version.h
index 5eb586c0bd..bbde6d371a 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,8 @@
#ifndef VERSION_H
#define VERSION_H
+struct repository;
+
extern const char git_version_string[];
extern const char git_built_from_commit_string[];
@@ -14,4 +16,5 @@ const char *git_user_agent_sanitized(void);
*/
int get_uname_info(struct strbuf *buf, unsigned int full);
+
#endif /* VERSION_H */
--
2.48.1
