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* [PATCH 0/3] msysgit fallout
@ 2007-11-21 20:27 Steffen Prohaska
  2007-11-21 20:27 ` [PATCH 1/3] sha1_file.c: Fix size_t related printf format warnings Steffen Prohaska
  0 siblings, 1 reply; 18+ messages in thread
From: Steffen Prohaska @ 2007-11-21 20:27 UTC (permalink / raw)
  To: git

Here are three patches that come from msysgit.  They do not bring
any functional changes, but only clean up code, or fix warnings.

    Steffen

 builtin-init-db.c |    4 +---
 git.c             |    6 +++---
 path.c            |    2 +-
 setup.c           |    2 +-
 sha1_file.c       |   10 ++++++----
 5 files changed, 12 insertions(+), 12 deletions(-)

 [PATCH 1/3] sha1_file.c: Fix size_t related printf format warnings
 [PATCH 2/3] builtin-init-db: use get_git_dir() instead of getenv()
 [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()

^ permalink raw reply	[flat|nested] 18+ messages in thread

* [PATCH 1/3] sha1_file.c: Fix size_t related printf format warnings
  2007-11-21 20:27 [PATCH 0/3] msysgit fallout Steffen Prohaska
@ 2007-11-21 20:27 ` Steffen Prohaska
  2007-11-21 20:27   ` [PATCH 2/3] builtin-init-db: use get_git_dir() instead of getenv() Steffen Prohaska
  0 siblings, 1 reply; 18+ messages in thread
From: Steffen Prohaska @ 2007-11-21 20:27 UTC (permalink / raw)
  To: git; +Cc: Steffen Prohaska

The old way of fixing warnings did not succeed on MinGW.  MinGW
does not support C99 printf format strings for size_t [1].  But
gcc on MinGW issues warnings if C99 printf format is not used.
Hence, the old stragegy to avoid warnings fails.

[1] http://www.mingw.org/MinGWiki/index.php/C99

This commits passes arguments of type size_t through a tiny
helper functions that casts to the type expected by the format
string.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
---
 sha1_file.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index f007874..4f68e53 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -25,8 +25,10 @@
 
 #ifdef NO_C99_FORMAT
 #define SZ_FMT "lu"
+static unsigned long sz_fmt(size_t s) { return (unsigned long)s; }
 #else
 #define SZ_FMT "zu"
+static size_t sz_fmt(size_t s) { return s; }
 #endif
 
 const unsigned char null_sha1[20];
@@ -423,9 +425,9 @@ void pack_report(void)
 		"pack_report: getpagesize()            = %10" SZ_FMT "\n"
 		"pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
 		"pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
-		(size_t) getpagesize(),
-		packed_git_window_size,
-		packed_git_limit);
+		sz_fmt(getpagesize()),
+		sz_fmt(packed_git_window_size),
+		sz_fmt(packed_git_limit));
 	fprintf(stderr,
 		"pack_report: pack_used_ctr            = %10u\n"
 		"pack_report: pack_mmap_calls          = %10u\n"
@@ -435,7 +437,7 @@ void pack_report(void)
 		pack_used_ctr,
 		pack_mmap_calls,
 		pack_open_windows, peak_pack_open_windows,
-		pack_mapped, peak_pack_mapped);
+		sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
 }
 
 static int check_packed_git_idx(const char *path,  struct packed_git *p)
-- 
1.5.3.5.750.g8692

^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [PATCH 2/3] builtin-init-db: use get_git_dir() instead of getenv()
  2007-11-21 20:27 ` [PATCH 1/3] sha1_file.c: Fix size_t related printf format warnings Steffen Prohaska
@ 2007-11-21 20:27   ` Steffen Prohaska
  2007-11-21 20:27     ` [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir() Steffen Prohaska
  0 siblings, 1 reply; 18+ messages in thread
From: Steffen Prohaska @ 2007-11-21 20:27 UTC (permalink / raw)
  To: git; +Cc: Steffen Prohaska

We have a function get_git_dir().  So let's use it,
instead of querying the environment.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
---
 builtin-init-db.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/builtin-init-db.c b/builtin-init-db.c
index 763fa55..80d2f27 100644
--- a/builtin-init-db.c
+++ b/builtin-init-db.c
@@ -378,9 +378,7 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 	/*
 	 * Set up the default .git directory contents
 	 */
-	git_dir = getenv(GIT_DIR_ENVIRONMENT);
-	if (!git_dir)
-		git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
+	git_dir = get_git_dir();
 	safe_create_dir(git_dir, 0);
 
 	/* Check to see if the repository version is right.
-- 
1.5.3.5.750.g8692

^ permalink raw reply related	[flat|nested] 18+ messages in thread

* [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-21 20:27   ` [PATCH 2/3] builtin-init-db: use get_git_dir() instead of getenv() Steffen Prohaska
@ 2007-11-21 20:27     ` Steffen Prohaska
  2007-11-22  1:22       ` Johannes Schindelin
  0 siblings, 1 reply; 18+ messages in thread
From: Steffen Prohaska @ 2007-11-21 20:27 UTC (permalink / raw)
  To: git; +Cc: Dmitry Kakurin, Steffen Prohaska

From: Dmitry Kakurin <Dmitry.Kakurin@gmail.com>

We have a function set_git_dir().  So let's use it, instead
of setting the evironment directly.

This also fixes a problem on Windows: environment.c caches
results of many getenv calls.  A setenv(X) call to the Windows
C runtime (CRT) invalidates all previous values returned by
getenv(X).  So cached values become dangling pointers.

Before this change, git clone was failing with 'invalid object
name HEAD' if ran from Windows' cmd.exe.

[sp: rebased; split off get_git_dir() in builtin-init-db.c
     to separate commit; adjusted commit message. ]

Signed-off-by: Dmitry Kakurin <Dmitry.Kakurin@gmail.com>
Signed-off-by: Steffen Prohaska <prohaska@zib.de>
---
 git.c   |    6 +++---
 path.c  |    2 +-
 setup.c |    2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/git.c b/git.c
index 7604319..8bc25b7 100644
--- a/git.c
+++ b/git.c
@@ -45,14 +45,14 @@ static int handle_options(const char*** argv, int* argc, int* envchanged)
 				fprintf(stderr, "No directory given for --git-dir.\n" );
 				usage(git_usage_string);
 			}
-			setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
+			set_git_dir( (*argv)[1] );
 			if (envchanged)
 				*envchanged = 1;
 			(*argv)++;
 			(*argc)--;
 			handled++;
 		} else if (!prefixcmp(cmd, "--git-dir=")) {
-			setenv(GIT_DIR_ENVIRONMENT, cmd + 10, 1);
+			set_git_dir(cmd + 10);
 			if (envchanged)
 				*envchanged = 1;
 		} else if (!strcmp(cmd, "--work-tree")) {
@@ -72,7 +72,7 @@ static int handle_options(const char*** argv, int* argc, int* envchanged)
 		} else if (!strcmp(cmd, "--bare")) {
 			static char git_dir[PATH_MAX+1];
 			is_bare_repository_cfg = 1;
-			setenv(GIT_DIR_ENVIRONMENT, getcwd(git_dir, sizeof(git_dir)), 0);
+			set_git_dir(getcwd(git_dir, sizeof(git_dir)));
 			if (envchanged)
 				*envchanged = 1;
 		} else {
diff --git a/path.c b/path.c
index 4260952..f26a4a1 100644
--- a/path.c
+++ b/path.c
@@ -248,7 +248,7 @@ char *enter_repo(char *path, int strict)
 
 	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
 	    validate_headref("HEAD") == 0) {
-		setenv(GIT_DIR_ENVIRONMENT, ".", 1);
+		set_git_dir(".");
 		check_repository_format();
 		return path;
 	}
diff --git a/setup.c b/setup.c
index 43cd3f9..8dbd46c 100644
--- a/setup.c
+++ b/setup.c
@@ -285,7 +285,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 			inside_git_dir = 1;
 			if (!work_tree_env)
 				inside_work_tree = 0;
-			setenv(GIT_DIR_ENVIRONMENT, ".", 1);
+			set_git_dir(".");
 			return NULL;
 		}
 		chdir("..");
-- 
1.5.3.5.750.g8692

^ permalink raw reply related	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-21 20:27     ` [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir() Steffen Prohaska
@ 2007-11-22  1:22       ` Johannes Schindelin
  2007-11-22  2:34         ` Junio C Hamano
  0 siblings, 1 reply; 18+ messages in thread
From: Johannes Schindelin @ 2007-11-22  1:22 UTC (permalink / raw)
  To: Steffen Prohaska; +Cc: git, Dmitry Kakurin

Hi,

On Wed, 21 Nov 2007, Steffen Prohaska wrote:

> We have a function set_git_dir().  So let's use it, instead of setting 
> the evironment directly.

Does this not have a fundamental issue?  When you call other git programs 
with run_command(), you _need_ GIT_DIR to be set, no?

Ciao,
Dscho

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-22  1:22       ` Johannes Schindelin
@ 2007-11-22  2:34         ` Junio C Hamano
  2007-11-22  6:13           ` Steffen Prohaska
  2007-11-22  7:29           ` Johannes Sixt
  0 siblings, 2 replies; 18+ messages in thread
From: Junio C Hamano @ 2007-11-22  2:34 UTC (permalink / raw)
  To: Johannes Schindelin; +Cc: Steffen Prohaska, git, Dmitry Kakurin

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

> Hi,
>
> On Wed, 21 Nov 2007, Steffen Prohaska wrote:
>
>> We have a function set_git_dir().  So let's use it, instead of setting 
>> the evironment directly.
>
> Does this not have a fundamental issue?  When you call other git programs 
> with run_command(), you _need_ GIT_DIR to be set, no?

It is much worse.  set_git_dir() does not just setenv() but does
setup_git_env() as well.

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-22  2:34         ` Junio C Hamano
@ 2007-11-22  6:13           ` Steffen Prohaska
  2007-11-22  7:52             ` Junio C Hamano
  2007-11-22  7:29           ` Johannes Sixt
  1 sibling, 1 reply; 18+ messages in thread
From: Steffen Prohaska @ 2007-11-22  6:13 UTC (permalink / raw)
  To: Junio C Hamano; +Cc: Johannes Schindelin, git, Dmitry Kakurin


On Nov 22, 2007, at 3:34 AM, Junio C Hamano wrote:

> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>
>> Hi,
>>
>> On Wed, 21 Nov 2007, Steffen Prohaska wrote:
>>
>>> We have a function set_git_dir().  So let's use it, instead of  
>>> setting
>>> the evironment directly.
>>
>> Does this not have a fundamental issue?  When you call other git  
>> programs
>> with run_command(), you _need_ GIT_DIR to be set, no?
>
> It is much worse.  set_git_dir() does not just setenv() but does
> setup_git_env() as well.

What do your comments mean?

My understanding is that set_git_dir() sets the environment and
then calls setup_git_env() to cache all pointers.  This call
updates dangling pointer if they have been cached earlier.

But maybe there is a hidden secret that I don't see.

	Steffen

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-22  2:34         ` Junio C Hamano
  2007-11-22  6:13           ` Steffen Prohaska
@ 2007-11-22  7:29           ` Johannes Sixt
  1 sibling, 0 replies; 18+ messages in thread
From: Johannes Sixt @ 2007-11-22  7:29 UTC (permalink / raw)
  To: Junio C Hamano; +Cc: Johannes Schindelin, Steffen Prohaska, git, Dmitry Kakurin

Junio C Hamano schrieb:
> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
> 
>> Hi,
>>
>> On Wed, 21 Nov 2007, Steffen Prohaska wrote:
>>
>>> We have a function set_git_dir().  So let's use it, instead of setting 
>>> the evironment directly.
>> Does this not have a fundamental issue?  When you call other git programs 
>> with run_command(), you _need_ GIT_DIR to be set, no?
> 
> It is much worse.  set_git_dir() does not just setenv() but does
> setup_git_env() as well.

I don't see what's wrong with that. Could you please explain?

-- Hannes

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-22  6:13           ` Steffen Prohaska
@ 2007-11-22  7:52             ` Junio C Hamano
  2007-11-22  8:31               ` Steffen Prohaska
  0 siblings, 1 reply; 18+ messages in thread
From: Junio C Hamano @ 2007-11-22  7:52 UTC (permalink / raw)
  To: Steffen Prohaska; +Cc: Johannes Schindelin, git, Dmitry Kakurin

Steffen Prohaska <prohaska@zib.de> writes:

> On Nov 22, 2007, at 3:34 AM, Junio C Hamano wrote:
>
>> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>>
>>> Does this not have a fundamental issue?  When you call other git
>>> programs
>>> with run_command(), you _need_ GIT_DIR to be set, no?
>>
>> It is much worse.  set_git_dir() does not just setenv() but does
>> setup_git_env() as well.
>
> What do your comments mean?
>
> My understanding is that set_git_dir() sets the environment and
> then calls setup_git_env() to cache all pointers.  This call
> updates dangling pointer if they have been cached earlier.

Well, I was agreeing with you.  "Worse" was about what the
current code does _not_ do.

If there are earlier calls that obtain locations relative to the
earlier definition of GIT_DIR, the locations they obtained are
not just stored in memory that is "dangling" (which was what
your proposed log message described) but they are also
inconsistent with the updated definition of GIT_DIR.

I suspect Johannes mistook set_git_dir() was only local
(i.e. per calling process) matter without noticing that it has
its own setenv() when he made that comment, hence my response to
point out that the current code only calls setenv(), but
set_git_dir() does setup_git_env() too, which should hide the
inconsistency problem.

HOWEVER.

I suspect that if there are even earlier callers than these
early parts in the codepaths (handle_options, enter_repo, and
setup_git_directory_gently), maybe these earlier callers are
doing something wrong.  Logically, if you are somewhere very
early in the codepath that you can still change the value of
GIT_DIR, you shouldn't have assumed the unknown value of GIT_DIR
and cached locations relative to that directory, no?  What are
the problematic callers?  What values do they access and why?

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-22  7:52             ` Junio C Hamano
@ 2007-11-22  8:31               ` Steffen Prohaska
  2007-11-22  9:58                 ` Johannes Sixt
  0 siblings, 1 reply; 18+ messages in thread
From: Steffen Prohaska @ 2007-11-22  8:31 UTC (permalink / raw)
  To: Junio C Hamano; +Cc: Johannes Schindelin, git, Dmitry Kakurin


On Nov 22, 2007, at 8:52 AM, Junio C Hamano wrote:

> Steffen Prohaska <prohaska@zib.de> writes:
>
>> On Nov 22, 2007, at 3:34 AM, Junio C Hamano wrote:
>>
>>> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>>>
>>>> Does this not have a fundamental issue?  When you call other git
>>>> programs
>>>> with run_command(), you _need_ GIT_DIR to be set, no?
>>>
>>> It is much worse.  set_git_dir() does not just setenv() but does
>>> setup_git_env() as well.
>>
>> What do your comments mean?
>>
>> My understanding is that set_git_dir() sets the environment and
>> then calls setup_git_env() to cache all pointers.  This call
>> updates dangling pointer if they have been cached earlier.
>
> Well, I was agreeing with you.  "Worse" was about what the
> current code does _not_ do.
>
> If there are earlier calls that obtain locations relative to the
> earlier definition of GIT_DIR, the locations they obtained are
> not just stored in memory that is "dangling" (which was what
> your proposed log message described) but they are also
> inconsistent with the updated definition of GIT_DIR.
>
> I suspect Johannes mistook set_git_dir() was only local
> (i.e. per calling process) matter without noticing that it has
> its own setenv() when he made that comment, hence my response to
> point out that the current code only calls setenv(), but
> set_git_dir() does setup_git_env() too, which should hide the
> inconsistency problem.
>
> HOWEVER.
>
> I suspect that if there are even earlier callers than these
> early parts in the codepaths (handle_options, enter_repo, and
> setup_git_directory_gently), maybe these earlier callers are
> doing something wrong.  Logically, if you are somewhere very
> early in the codepath that you can still change the value of
> GIT_DIR, you shouldn't have assumed the unknown value of GIT_DIR
> and cached locations relative to that directory, no?  What are
> the problematic callers?  What values do they access and why?


I thought about these questions, too.  But only very briefly.
I did not analyze the code path that lead to calls of getenv().

I'm not sure if it's really necessary.  Calling set_git_dir()
looks more sensible too me than the old code.  I believe using
set_git_dir() is the safer choice, and should not do any harm.
So I stopped analyzing too much, and instead proposed to use
set_git_dir().

Interesting, though, is to find out if we have other potentially
dangerous calls to getenv() that are not removed by this patch.

	Steffen

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-22  8:31               ` Steffen Prohaska
@ 2007-11-22  9:58                 ` Johannes Sixt
  2007-11-22 17:56                   ` Steffen Prohaska
  0 siblings, 1 reply; 18+ messages in thread
From: Johannes Sixt @ 2007-11-22  9:58 UTC (permalink / raw)
  To: Steffen Prohaska; +Cc: Junio C Hamano, Johannes Schindelin, git, Dmitry Kakurin

Steffen Prohaska schrieb:
> On Nov 22, 2007, at 8:52 AM, Junio C Hamano wrote:
>> I suspect that if there are even earlier callers than these
>> early parts in the codepaths (handle_options, enter_repo, and
>> setup_git_directory_gently), maybe these earlier callers are
>> doing something wrong.  Logically, if you are somewhere very
>> early in the codepath that you can still change the value of
>> GIT_DIR, you shouldn't have assumed the unknown value of GIT_DIR
>> and cached locations relative to that directory, no?  What are
>> the problematic callers?  What values do they access and why?
> 
> 
> I thought about these questions, too.  But only very briefly.
> I did not analyze the code path that lead to calls of getenv().
> 
> I'm not sure if it's really necessary.  Calling set_git_dir()
> looks more sensible too me than the old code.  I believe using
> set_git_dir() is the safer choice, and should not do any harm.
> So I stopped analyzing too much, and instead proposed to use
> set_git_dir().

Junio's point is this: If we stumble over a dangling pointer that getenv() 
produced, then this has obviously happened before setenv(GIT_DIR), and 
caching that pointer is probably the wrong thing to do anyway (because it 
refers to the wrong GIT_DIR) and needs to be fixed.

So the task is to find those traps. Dmitry obviously stumbled over one case, 
but I haven't ever encountered any problems with the current code. But then 
this might be sheer luck. And I'm not a heavy user of export GIT_DIR=foo, 
either. Do *you* know a problematic case?

> Interesting, though, is to find out if we have other potentially
> dangerous calls to getenv() that are not removed by this patch.

Side note for other readers: This is a Windows specific problem for the 
moment because its getenv() does not behave well.

-- Hannes

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-22  9:58                 ` Johannes Sixt
@ 2007-11-22 17:56                   ` Steffen Prohaska
  2007-11-22 22:09                     ` Johannes Schindelin
  2008-01-01 18:52                     ` Steffen Prohaska
  0 siblings, 2 replies; 18+ messages in thread
From: Steffen Prohaska @ 2007-11-22 17:56 UTC (permalink / raw)
  To: Johannes Sixt; +Cc: Junio C Hamano, Johannes Schindelin, git, Dmitry Kakurin


On Nov 22, 2007, at 10:58 AM, Johannes Sixt wrote:

> Steffen Prohaska schrieb:
>> On Nov 22, 2007, at 8:52 AM, Junio C Hamano wrote:
>>> I suspect that if there are even earlier callers than these
>>> early parts in the codepaths (handle_options, enter_repo, and
>>> setup_git_directory_gently), maybe these earlier callers are
>>> doing something wrong.  Logically, if you are somewhere very
>>> early in the codepath that you can still change the value of
>>> GIT_DIR, you shouldn't have assumed the unknown value of GIT_DIR
>>> and cached locations relative to that directory, no?  What are
>>> the problematic callers?  What values do they access and why?
>> I thought about these questions, too.  But only very briefly.
>> I did not analyze the code path that lead to calls of getenv().
>> I'm not sure if it's really necessary.  Calling set_git_dir()
>> looks more sensible too me than the old code.  I believe using
>> set_git_dir() is the safer choice, and should not do any harm.
>> So I stopped analyzing too much, and instead proposed to use
>> set_git_dir().
>
> Junio's point is this: If we stumble over a dangling pointer that  
> getenv() produced, then this has obviously happened before setenv 
> (GIT_DIR), and caching that pointer is probably the wrong thing to  
> do anyway (because it refers to the wrong GIT_DIR) and needs to be  
> fixed.

I see your point.  It is probably more important to investigate
this than I recognized at a first glance.


> So the task is to find those traps. Dmitry obviously stumbled over  
> one case, but I haven't ever encountered any problems with the  
> current code. But then this might be sheer luck. And I'm not a  
> heavy user of export GIT_DIR=foo, either. Do *you* know a  
> problematic case?

No.  I only stumbled over the code, when I reviewed differences
between msysgit and mingw.  I rarely use GIT_DIR=foo.  Actually,
I can't remember the last time I did.


>> Interesting, though, is to find out if we have other potentially
>> dangerous calls to getenv() that are not removed by this patch.
>
> Side note for other readers: This is a Windows specific problem for  
> the moment because its getenv() does not behave well.

Yes, and apparently even nobody knows how to trigger the problem
on Windows.  At this point, we only know that caching getenv()
calls is unsafe, while on Unix it is safe (at least for BSD
it's documented to be safe).

	Steffen

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-22 17:56                   ` Steffen Prohaska
@ 2007-11-22 22:09                     ` Johannes Schindelin
  2008-01-01 18:52                     ` Steffen Prohaska
  1 sibling, 0 replies; 18+ messages in thread
From: Johannes Schindelin @ 2007-11-22 22:09 UTC (permalink / raw)
  To: Steffen Prohaska; +Cc: Johannes Sixt, Junio C Hamano, git, Dmitry Kakurin

Hi,

On Thu, 22 Nov 2007, Steffen Prohaska wrote:

> Yes, and apparently even nobody knows how to trigger the problem on 
> Windows.

A quick and easy way would be to instrument getenv(), unsetenv() and 
setenv(), which would trigger an error.  Something like this (but you 
will have to put in a few "extern called_getenv; called_getenv = 0;", 
since already a simple git-init fails because of setup_path()):

-- snipsnap --
[PATCH] Instrument getenv(), setenv(), unsetenv() and putenv()

... for finding places where a pointer obtained by getenv() could
be invalidated later.

---

 environment.c     |    1 +
 git-compat-util.h |   31 +++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/environment.c b/environment.c
index ce75e98..027340e 100644
--- a/environment.c
+++ b/environment.c
@@ -9,6 +9,7 @@
  */
 #include "cache.h"
 
+int called_setenv, called_getenv;
 char git_default_email[MAX_GITNAME];
 char git_default_name[MAX_GITNAME];
 int trust_executable_bit = 1;
diff --git a/git-compat-util.h b/git-compat-util.h
index 79eb10e..a41469b 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -427,4 +427,35 @@ static inline int strtol_i(char const *s, int base, int *result)
 	return 0;
 }
 
+extern int called_setenv, called_getenv;
+static inline char *test_getenv(const char *name)
+{
+	if (!called_setenv)
+		warning ("called test_getenv %s", name);
+	called_getenv = 1;
+	return getenv(name);
+}
+static inline int test_setenv(const char *name, const char *value, int overwrite)
+{
+	if (!called_setenv && called_getenv)
+		die ("getenv was called before setenv(%s, %s, %d)",
+				name, value, overwrite);
+	return setenv(name, value, overwrite);
+}
+static inline int test_unsetenv(const char *name)
+{
+	if (!called_setenv && called_getenv)
+		die ("getenv was called before unsetenv(%s)", name);
+	return unsetenv(name);
+}
+static inline int test_putenv(char *string)
+{
+	if (!called_setenv && called_getenv)
+		die ("getenv was called before putenv(%s)", string);
+	return putenv(string);
+}
+#define getenv test_getenv
+#define setenv test_setenv
+#define unsetenv test_unsetenv
+
 #endif

^ permalink raw reply related	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2007-11-22 17:56                   ` Steffen Prohaska
  2007-11-22 22:09                     ` Johannes Schindelin
@ 2008-01-01 18:52                     ` Steffen Prohaska
  2008-01-03  4:07                       ` Dmitry Kakurin
  1 sibling, 1 reply; 18+ messages in thread
From: Steffen Prohaska @ 2008-01-01 18:52 UTC (permalink / raw)
  To: Git Mailing List
  Cc: Johannes Sixt, Junio C Hamano, Johannes Schindelin,
	Dmitry Kakurin

Eventually I found some time to investigate this issue ...


On Nov 22, 2007, at 6:56 PM, Steffen Prohaska wrote:

>
> On Nov 22, 2007, at 10:58 AM, Johannes Sixt wrote:
>
>> Steffen Prohaska schrieb:
>>> On Nov 22, 2007, at 8:52 AM, Junio C Hamano wrote:
>>>> I suspect that if there are even earlier callers than these
>>>> early parts in the codepaths (handle_options, enter_repo, and
>>>> setup_git_directory_gently), maybe these earlier callers are
>>>> doing something wrong.  Logically, if you are somewhere very
>>>> early in the codepath that you can still change the value of
>>>> GIT_DIR, you shouldn't have assumed the unknown value of GIT_DIR
>>>> and cached locations relative to that directory, no?  What are
>>>> the problematic callers?  What values do they access and why?
>>> I thought about these questions, too.  But only very briefly.
>>> I did not analyze the code path that lead to calls of getenv().
>>> I'm not sure if it's really necessary.  Calling set_git_dir()
>>> looks more sensible too me than the old code.  I believe using
>>> set_git_dir() is the safer choice, and should not do any harm.
>>> So I stopped analyzing too much, and instead proposed to use
>>> set_git_dir().
>>
>> Junio's point is this: If we stumble over a dangling pointer that  
>> getenv() produced, then this has obviously happened before setenv 
>> (GIT_DIR), and caching that pointer is probably the wrong thing to  
>> do anyway (because it refers to the wrong GIT_DIR) and needs to be  
>> fixed.
>
> I see your point.  It is probably more important to investigate
> this than I recognized at a first glance.

I instrumented the code to verify if setenv(GIT_DIR) is called after
setup_git_env().  This is not the case for all tests.

I also searched for problematic code paths.

setup_git_directory_gently() looks correct.  It explicitly calls
getenv(GIT_DIR_ENVIRONMENT); but uses the value returned in a
safe manner.  It does not cache the result and the only code path
that calls set_git_dir() does not access the return value of the
getenv() call after the call to set_git_dir().

setup_work_tree() looks correct, too.  Here, get_git_dir() is
called, which implicitly results in caching the pointer returned
from getenv(GIT_DIR_ENVIRONMENT).  But the result of get_git_dir() is
neither cached nor used after a subsequent call to set_git_dir().

So, I don't find any obvious problems.


>>> Interesting, though, is to find out if we have other potentially
>>> dangerous calls to getenv() that are not removed by this patch.
>>
>> Side note for other readers: This is a Windows specific problem  
>> for the moment because its getenv() does not behave well.
>
> Yes, and apparently even nobody knows how to trigger the problem
> on Windows.  At this point, we only know that caching getenv()
> calls is unsafe, while on Unix it is safe (at least for BSD
> it's documented to be safe).

In conclusion, using setenv() as in the original code instead of
set_git_dir() should be safe and this patch is not needed.

I tend to revert the changes in msysgit and see if we hit any
problems.  But I'll wait until 1.5.4 is released.

	Steffen

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2008-01-01 18:52                     ` Steffen Prohaska
@ 2008-01-03  4:07                       ` Dmitry Kakurin
  2008-01-03  6:02                         ` Steffen Prohaska
  0 siblings, 1 reply; 18+ messages in thread
From: Dmitry Kakurin @ 2008-01-03  4:07 UTC (permalink / raw)
  To: Steffen Prohaska
  Cc: Git Mailing List, Johannes Sixt, Junio C Hamano,
	Johannes Schindelin

On Jan 1, 2008 10:52 AM, Steffen Prohaska <prohaska@zib.de> wrote:
> In conclusion, using setenv() as in the original code instead of
> set_git_dir() should be safe and this patch is not needed.
>
> I tend to revert the changes in msysgit and see if we hit any
> problems.  But I'll wait until 1.5.4 is released.
>
>        Steffen

Please don't revert this change. I've made it in response to git clone
failing, commit 855f254b2b5b083a63fc8d7709a42e2cbdc5a136.

-- 
- Dmitry

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2008-01-03  4:07                       ` Dmitry Kakurin
@ 2008-01-03  6:02                         ` Steffen Prohaska
  2008-01-03  6:26                           ` Dmitry Kakurin
  0 siblings, 1 reply; 18+ messages in thread
From: Steffen Prohaska @ 2008-01-03  6:02 UTC (permalink / raw)
  To: Dmitry Kakurin
  Cc: Git Mailing List, Johannes Sixt, Junio C Hamano,
	Johannes Schindelin


On Jan 3, 2008, at 5:07 AM, Dmitry Kakurin wrote:

> On Jan 1, 2008 10:52 AM, Steffen Prohaska <prohaska@zib.de> wrote:
>> In conclusion, using setenv() as in the original code instead of
>> set_git_dir() should be safe and this patch is not needed.
>>
>> I tend to revert the changes in msysgit and see if we hit any
>> problems.  But I'll wait until 1.5.4 is released.
>>
>>        Steffen
>
> Please don't revert this change. I've made it in response to git clone
> failing, commit 855f254b2b5b083a63fc8d7709a42e2cbdc5a136.

I know.  But I cannot reproduce the error.

Do you have a test case that demonstrates the problem?

I either want to see the patch upstream in official git or revert
it in msysgit.  But I cannot answer the questions that were
raised after I sent the patch (see earlier in this thread).  And
I can't see the problem that your patch solves, even after
spending some time on reading and instrumenting code.

	Steffen

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2008-01-03  6:02                         ` Steffen Prohaska
@ 2008-01-03  6:26                           ` Dmitry Kakurin
  2008-01-03  7:53                             ` Steffen Prohaska
  0 siblings, 1 reply; 18+ messages in thread
From: Dmitry Kakurin @ 2008-01-03  6:26 UTC (permalink / raw)
  To: Steffen Prohaska
  Cc: Git Mailing List, Johannes Sixt, Junio C Hamano,
	Johannes Schindelin

On Jan 2, 2008 10:02 PM, Steffen Prohaska <prohaska@zib.de> wrote:
>
>
> On Jan 3, 2008, at 5:07 AM, Dmitry Kakurin wrote:
>
> > On Jan 1, 2008 10:52 AM, Steffen Prohaska <prohaska@zib.de> wrote:
> >> In conclusion, using setenv() as in the original code instead of
> >> set_git_dir() should be safe and this patch is not needed.
> >>
> >> I tend to revert the changes in msysgit and see if we hit any
> >> problems.  But I'll wait until 1.5.4 is released.
> >>
> >>        Steffen
> >
> > Please don't revert this change. I've made it in response to git clone
> > failing, commit 855f254b2b5b083a63fc8d7709a42e2cbdc5a136.
>
> I know.  But I cannot reproduce the error.
>
> Do you have a test case that demonstrates the problem?
>
> I either want to see the patch upstream in official git or revert
> it in msysgit.  But I cannot answer the questions that were
> raised after I sent the patch (see earlier in this thread).  And
> I can't see the problem that your patch solves, even after
> spending some time on reading and instrumenting code.

I remember that the problem was as simple as git clone or git clone
--bare failing.
Also I'm not sure if it matters but I'm running Vista.
There is also a chance that code has changed since then and this
problem went away.

-- 
- Dmitry

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir()
  2008-01-03  6:26                           ` Dmitry Kakurin
@ 2008-01-03  7:53                             ` Steffen Prohaska
  0 siblings, 0 replies; 18+ messages in thread
From: Steffen Prohaska @ 2008-01-03  7:53 UTC (permalink / raw)
  To: Dmitry Kakurin
  Cc: Git Mailing List, Johannes Sixt, Junio C Hamano,
	Johannes Schindelin


On Jan 3, 2008, at 7:26 AM, Dmitry Kakurin wrote:

> On Jan 2, 2008 10:02 PM, Steffen Prohaska <prohaska@zib.de> wrote:
>>
>>
>> On Jan 3, 2008, at 5:07 AM, Dmitry Kakurin wrote:
>>
>>> On Jan 1, 2008 10:52 AM, Steffen Prohaska <prohaska@zib.de> wrote:
>>>> In conclusion, using setenv() as in the original code instead of
>>>> set_git_dir() should be safe and this patch is not needed.
>>>>
>>>> I tend to revert the changes in msysgit and see if we hit any
>>>> problems.  But I'll wait until 1.5.4 is released.
>>>>
>>>>        Steffen
>>>
>>> Please don't revert this change. I've made it in response to git  
>>> clone
>>> failing, commit 855f254b2b5b083a63fc8d7709a42e2cbdc5a136.
>>
>> I know.  But I cannot reproduce the error.
>>
>> Do you have a test case that demonstrates the problem?
>>
>> I either want to see the patch upstream in official git or revert
>> it in msysgit.  But I cannot answer the questions that were
>> raised after I sent the patch (see earlier in this thread).  And
>> I can't see the problem that your patch solves, even after
>> spending some time on reading and instrumenting code.
>
> I remember that the problem was as simple as git clone or git clone
> --bare failing.

This is what I understood from the commit message.

I need a script that I can run to see the error.  All tests that
come with git pass (on my machine).


> Also I'm not sure if it matters but I'm running Vista.

It only matters if you see an error on Vista that I don't see on
XP.  If this was the case I'd debug on Vista.


> There is also a chance that code has changed since then and this
> problem went away.

Maybe.

	Steffen

^ permalink raw reply	[flat|nested] 18+ messages in thread

end of thread, other threads:[~2008-01-03  7:53 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-11-21 20:27 [PATCH 0/3] msysgit fallout Steffen Prohaska
2007-11-21 20:27 ` [PATCH 1/3] sha1_file.c: Fix size_t related printf format warnings Steffen Prohaska
2007-11-21 20:27   ` [PATCH 2/3] builtin-init-db: use get_git_dir() instead of getenv() Steffen Prohaska
2007-11-21 20:27     ` [PATCH 3/3] Replace setenv(GIT_DIR_ENVIRONMENT, ...) with set_git_dir() Steffen Prohaska
2007-11-22  1:22       ` Johannes Schindelin
2007-11-22  2:34         ` Junio C Hamano
2007-11-22  6:13           ` Steffen Prohaska
2007-11-22  7:52             ` Junio C Hamano
2007-11-22  8:31               ` Steffen Prohaska
2007-11-22  9:58                 ` Johannes Sixt
2007-11-22 17:56                   ` Steffen Prohaska
2007-11-22 22:09                     ` Johannes Schindelin
2008-01-01 18:52                     ` Steffen Prohaska
2008-01-03  4:07                       ` Dmitry Kakurin
2008-01-03  6:02                         ` Steffen Prohaska
2008-01-03  6:26                           ` Dmitry Kakurin
2008-01-03  7:53                             ` Steffen Prohaska
2007-11-22  7:29           ` Johannes Sixt

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