From 25a7c3293019cfec5bdb738b56c9ae032a54dd78 Mon Sep 17 00:00:00 2001 From: Amitay Isaacs Date: Thu, 12 Apr 2012 14:06:58 +1000 Subject: lib/talloc: Remove the files required to build talloc as a library Since talloc library will never be built from ctdb sources, we don't need the build related files. (This used to be ctdb commit 2cd6a7ce648c1d2cc4d5580c3809858c100fa930) --- ctdb/lib/talloc/talloc.3.html | 433 ------------------------------------------ 1 file changed, 433 deletions(-) delete mode 100644 ctdb/lib/talloc/talloc.3.html (limited to 'ctdb/lib/talloc/talloc.3.html') diff --git a/ctdb/lib/talloc/talloc.3.html b/ctdb/lib/talloc/talloc.3.html deleted file mode 100644 index 2459476435..0000000000 --- a/ctdb/lib/talloc/talloc.3.html +++ /dev/null @@ -1,433 +0,0 @@ -talloc

Name

talloc — hierarchical reference counted memory pool system with destructors

Synopsis

#include <talloc/talloc.h>

DESCRIPTION

- If you are used to talloc from Samba3 then please read this - carefully, as talloc has changed a lot. -

- The new talloc is a hierarchical, reference counted memory pool - system with destructors. Quite a mouthful really, but not too bad - once you get used to it. -

- Perhaps the biggest change from Samba3 is that there is no - distinction between a "talloc context" and a "talloc pointer". Any - pointer returned from talloc() is itself a valid talloc context. - This means you can do this: - 

-    struct foo *X = talloc(mem_ctx, struct foo);
-    X->name = talloc_strdup(X, "foo");
-

- and the pointer X->name - would be a "child" of the talloc context X which is itself a child of - mem_ctx. So if you do - talloc_free(mem_ctx) then - it is all destroyed, whereas if you do talloc_free(X) then just X and X->name are destroyed, and if - you do talloc_free(X->name) then just - the name element of X is - destroyed. -

- If you think about this, then what this effectively gives you is an - n-ary tree, where you can free any part of the tree with - talloc_free(). -

- If you find this confusing, then I suggest you run the testsuite program to watch talloc - in action. You may also like to add your own tests to testsuite.c to clarify how some - particular situation is handled. -

TALLOC API

- The following is a complete guide to the talloc API. Read it all at - least twice. -

(type *)talloc(const void *ctx, type);

- The talloc() macro is the core of the talloc library. It takes a - memory ctx and a type, and returns a pointer to a new - area of memory of the given type. -

- The returned pointer is itself a talloc context, so you can use - it as the ctx argument to more - calls to talloc() if you wish. -

- The returned pointer is a "child" of the supplied context. This - means that if you talloc_free() the ctx then the new child disappears as - well. Alternatively you can free just the child. -

- The ctx argument to talloc() - can be NULL, in which case a new top level context is created. -

void *talloc_size(const void *ctx, size_t size);

- The function talloc_size() should be used when you don't have a - convenient type to pass to talloc(). Unlike talloc(), it is not - type safe (as it returns a void *), so you are on your own for - type checking. -

(typeof(ptr)) talloc_ptrtype(const void *ctx, ptr);

- The talloc_ptrtype() macro should be used when you have a pointer and - want to allocate memory to point at with this pointer. When compiling - with gcc >= 3 it is typesafe. Note this is a wrapper of talloc_size() - and talloc_get_name() will return the current location in the source file. - and not the type. -

int talloc_free(void *ptr);

- The talloc_free() function frees a piece of talloc memory, and - all its children. You can call talloc_free() on any pointer - returned by talloc(). -

- The return value of talloc_free() indicates success or failure, - with 0 returned for success and -1 for failure. The only - possible failure condition is if ptr had a destructor attached to it and - the destructor returned -1. See “talloc_set_destructor()” - for details on destructors. -

- If this pointer has an additional parent when talloc_free() is - called then the memory is not actually released, but instead the - most recently established parent is destroyed. See “talloc_reference()” - for details on establishing additional parents. -

- For more control on which parent is removed, see “talloc_unlink()”. -

- talloc_free() operates recursively on its children. -

void *talloc_reference(const void *ctx, const void *ptr);

- The talloc_reference() function makes ctx an additional parent of ptr. -

- The return value of talloc_reference() is always the original - pointer ptr, unless talloc ran - out of memory in creating the reference in which case it will - return NULL (each additional reference consumes around 48 bytes - of memory on intel x86 platforms). -

- If ptr is NULL, then the - function is a no-op, and simply returns NULL. -

- After creating a reference you can free it in one of the - following ways: -

-

  • - you can talloc_free() any parent of the original pointer. - That will reduce the number of parents of this pointer by 1, - and will cause this pointer to be freed if it runs out of - parents. -

  • - you can talloc_free() the pointer itself. That will destroy - the most recently established parent to the pointer and leave - the pointer as a child of its current parent. -

-

- For more control on which parent to remove, see “talloc_unlink()”. -

int talloc_unlink(const void *ctx, const void *ptr);

- The talloc_unlink() function removes a specific parent from - ptr. The ctx passed must either be a context used - in talloc_reference() with this pointer, or must be a direct - parent of ptr. -

- Note that if the parent has already been removed using - talloc_free() then this function will fail and will return -1. - Likewise, if ptr is NULL, then - the function will make no modifications and return -1. -

- Usually you can just use talloc_free() instead of - talloc_unlink(), but sometimes it is useful to have the - additional control on which parent is removed. -

void talloc_set_destructor(const void *ptr, int (*destructor)(void *));

- The function talloc_set_destructor() sets the destructor for the pointer ptr. A destructor is a function that is called - when the memory used by a pointer is about to be released. The - destructor receives ptr as an - argument, and should return 0 for success and -1 for failure. -

- The destructor can do anything - it wants to, including freeing other pieces of memory. A common - use for destructors is to clean up operating system resources - (such as open file descriptors) contained in the structure the - destructor is placed on. -

- You can only place one destructor on a pointer. If you need more - than one destructor then you can create a zero-length child of - the pointer and place an additional destructor on that. -

- To remove a destructor call talloc_set_destructor() with NULL for - the destructor. -

- If your destructor attempts to talloc_free() the pointer that it - is the destructor for then talloc_free() will return -1 and the - free will be ignored. This would be a pointless operation - anyway, as the destructor is only called when the memory is just - about to go away. -

int talloc_increase_ref_count(const void *ptr);

- The talloc_increase_ref_count(ptr) function is exactly equivalent to: - 

talloc_reference(NULL, ptr);

- You can use either syntax, depending on which you think is - clearer in your code. -

- It returns 0 on success and -1 on failure. -

size_t talloc_reference_count(const void *ptr);

- Return the number of references to the pointer. -

void talloc_set_name(const void *ptr, const char *fmt, ...);

- Each talloc pointer has a "name". The name is used principally - for debugging purposes, although it is also possible to set and - get the name on a pointer in as a way of "marking" pointers in - your code. -

- The main use for names on pointer is for "talloc reports". See - “talloc_report_depth_cb()”, - “talloc_report_depth_file()”, - “talloc_report()” - “talloc_report()” - and “talloc_report_full()” - for details. Also see “talloc_enable_leak_report()” - and “talloc_enable_leak_report_full()”. -

- The talloc_set_name() function allocates memory as a child of the - pointer. It is logically equivalent to: - 

talloc_set_name_const(ptr, talloc_asprintf(ptr, fmt, ...));

- Note that multiple calls to talloc_set_name() will allocate more - memory without releasing the name. All of the memory is released - when the ptr is freed using talloc_free(). -

void talloc_set_name_const(const void *ptr, const char *name);

- The function talloc_set_name_const() is just like - talloc_set_name(), but it takes a string constant, and is much - faster. It is extensively used by the "auto naming" macros, such - as talloc_p(). -

- This function does not allocate any memory. It just copies the - supplied pointer into the internal representation of the talloc - ptr. This means you must not pass a name pointer to memory that will - disappear before ptr is freed - with talloc_free(). -

void *talloc_named(const void *ctx, size_t size, const char *fmt, ...);

- The talloc_named() function creates a named talloc pointer. It - is equivalent to: - 

ptr = talloc_size(ctx, size);
-talloc_set_name(ptr, fmt, ....);

void *talloc_named_const(const void *ctx, size_t size, const char *name);

- This is equivalent to: - 

ptr = talloc_size(ctx, size);
-talloc_set_name_const(ptr, name);

const char *talloc_get_name(const void *ptr);

- This returns the current name for the given talloc pointer, - ptr. See “talloc_set_name()” - for details. -

void *talloc_init(const char *fmt, ...);

- This function creates a zero length named talloc context as a top - level context. It is equivalent to: - 

talloc_named(NULL, 0, fmt, ...);

void *talloc_new(void *ctx);

- This is a utility macro that creates a new memory context hanging - off an exiting context, automatically naming it "talloc_new: - __location__" where __location__ is the source line it is called - from. It is particularly useful for creating a new temporary - working context. -

(type *)talloc_realloc(const void *ctx, void *ptr, type, count);

- The talloc_realloc() macro changes the size of a talloc pointer. - It has the following equivalences: - 

talloc_realloc(ctx, NULL, type, 1) ==> talloc(ctx, type);
-talloc_realloc(ctx, ptr, type, 0)  ==> talloc_free(ptr);

- The ctx argument is only used - if ptr is not NULL, otherwise - it is ignored. -

- talloc_realloc() returns the new pointer, or NULL on failure. - The call will fail either due to a lack of memory, or because the - pointer has more than one parent (see “talloc_reference()”). -

void *talloc_realloc_size(const void *ctx, void *ptr, size_t size);

- the talloc_realloc_size() function is useful when the type is not - known so the type-safe talloc_realloc() cannot be used. -

TYPE *talloc_steal(const void *new_ctx, const TYPE *ptr);

- The talloc_steal() function changes the parent context of a - talloc pointer. It is typically used when the context that the - pointer is currently a child of is going to be freed and you wish - to keep the memory for a longer time. -

- The talloc_steal() function returns the pointer that you pass it. - It does not have any failure modes. -

- NOTE: It is possible to produce loops in the parent/child - relationship if you are not careful with talloc_steal(). No - guarantees are provided as to your sanity or the safety of your - data if you do this. -

TYPE *talloc_move(const void *new_ctx, TYPE **ptr);

- The talloc_move() function is a wrapper around - talloc_steal() which zeros the source pointer after the - move. This avoids a potential source of bugs where a - programmer leaves a pointer in two structures, and uses the - pointer from the old structure after it has been moved to a - new one. -

size_t talloc_total_size(const void *ptr);

- The talloc_total_size() function returns the total size in bytes - used by this pointer and all child pointers. Mostly useful for - debugging. -

- Passing NULL is allowed, but it will only give a meaningful - result if talloc_enable_leak_report() or - talloc_enable_leak_report_full() has been called. -

size_t talloc_total_blocks(const void *ptr);

- The talloc_total_blocks() function returns the total memory block - count used by this pointer and all child pointers. Mostly useful - for debugging. -

- Passing NULL is allowed, but it will only give a meaningful - result if talloc_enable_leak_report() or - talloc_enable_leak_report_full() has been called. -

void talloc_report(const void *ptr, FILE *f);

- The talloc_report() function prints a summary report of all - memory used by ptr. One line - of report is printed for each immediate child of ptr, showing the - total memory and number of blocks used by that child. -

- You can pass NULL for the pointer, in which case a report is - printed for the top level memory context, but only if - talloc_enable_leak_report() or talloc_enable_leak_report_full() - has been called. -

void talloc_report_full(const void *ptr, FILE *f);

- This provides a more detailed report than talloc_report(). It - will recursively print the entire tree of memory referenced by - the pointer. References in the tree are shown by giving the name - of the pointer that is referenced. -

- You can pass NULL for the pointer, in which case a report is - printed for the top level memory context, but only if - talloc_enable_leak_report() or talloc_enable_leak_report_full() - has been called. -

void talloc_report_depth_cb(const void *ptr,  
 int depth,  
 int max_depth,  
 void (*callback)(const void *ptr, int depth, int max_depth, int is_ref, void *priv),  
 void *priv); 
 const void *ptr;
 int depth;
 int max_depth;
 void (*callback)(const void *ptr, int depth, int max_depth, int is_ref, void *priv);
 void *priv;

- This provides a more flexible reports than talloc_report(). It - will recursively call the callback for the entire tree of memory - referenced by the pointer. References in the tree are passed with - is_ref = 1 and the pointer that is referenced. -

- You can pass NULL for the pointer, in which case a report is - printed for the top level memory context, but only if - talloc_enable_leak_report() or talloc_enable_leak_report_full() - has been called. -

- The recursion is stopped when depth >= max_depth. - max_depth = -1 means only stop at leaf nodes. -

void talloc_report_depth_file(const void *ptr,  
 int depth,  
 int max_depth,  
 FILE *f); 
 const void *ptr;
 int depth;
 int max_depth;
 FILE *f;

- This provides a more flexible reports than talloc_report(). It - will let you specify the depth and max_depth. -

void talloc_enable_leak_report(void);

- This enables calling of talloc_report(NULL, stderr) when the - program exits. In Samba4 this is enabled by using the - --leak-report command line option. -

- For it to be useful, this function must be called before any - other talloc function as it establishes a "null context" that - acts as the top of the tree. If you don't call this function - first then passing NULL to talloc_report() or - talloc_report_full() won't give you the full tree printout. -

- Here is a typical talloc report: - 

talloc report on 'null_context' (total 267 bytes in 15 blocks)
-libcli/auth/spnego_parse.c:55  contains   31 bytes in   2 blocks
-libcli/auth/spnego_parse.c:55  contains   31 bytes in   2 blocks
-iconv(UTF8,CP850)              contains   42 bytes in   2 blocks
-libcli/auth/spnego_parse.c:55  contains   31 bytes in   2 blocks
-iconv(CP850,UTF8)              contains   42 bytes in   2 blocks
-iconv(UTF8,UTF-16LE)           contains   45 bytes in   2 blocks
-iconv(UTF-16LE,UTF8)           contains   45 bytes in   2 blocks
-

void talloc_enable_leak_report_full(void);

- This enables calling of talloc_report_full(NULL, stderr) when the - program exits. In Samba4 this is enabled by using the - --leak-report-full command line option. -

- For it to be useful, this function must be called before any - other talloc function as it establishes a "null context" that - acts as the top of the tree. If you don't call this function - first then passing NULL to talloc_report() or - talloc_report_full() won't give you the full tree printout. -

- Here is a typical full report: - 

full talloc report on 'root' (total 18 bytes in 8 blocks)
-p1               contains     18 bytes in   7 blocks (ref 0)
-    r1               contains     13 bytes in   2 blocks (ref 0)
-        reference to: p2
-    p2               contains      1 bytes in   1 blocks (ref 1)
-    x3               contains      1 bytes in   1 blocks (ref 0)
-    x2               contains      1 bytes in   1 blocks (ref 0)
-    x1               contains      1 bytes in   1 blocks (ref 0)
-

(type *)talloc_zero(const void *ctx, type);

- The talloc_zero() macro is equivalent to: - 

ptr = talloc(ctx, type);
-if (ptr) memset(ptr, 0, sizeof(type));

void *talloc_zero_size(const void *ctx, size_t size)

- The talloc_zero_size() function is useful when you don't have a - known type. -

void *talloc_memdup(const void *ctx, const void *p, size_t size);

- The talloc_memdup() function is equivalent to: - 

ptr = talloc_size(ctx, size);
-if (ptr) memcpy(ptr, p, size);

char *talloc_strdup(const void *ctx, const char *p);

- The talloc_strdup() function is equivalent to: - 

ptr = talloc_size(ctx, strlen(p)+1);
-if (ptr) memcpy(ptr, p, strlen(p)+1);

- This function sets the name of the new pointer to the passed - string. This is equivalent to: - 

talloc_set_name_const(ptr, ptr)

char *talloc_strndup(const void *t, const char *p, size_t n);

- The talloc_strndup() function is the talloc equivalent of the C - library function strndup(3). -

- This function sets the name of the new pointer to the passed - string. This is equivalent to: - 

talloc_set_name_const(ptr, ptr)

char *talloc_vasprintf(const void *t, const char *fmt, va_list ap);

- The talloc_vasprintf() function is the talloc equivalent of the C - library function vasprintf(3). -

char *talloc_asprintf(const void *t, const char *fmt, ...);

- The talloc_asprintf() function is the talloc equivalent of the C - library function asprintf(3). -

- This function sets the name of the new pointer to the passed - string. This is equivalent to: - 

talloc_set_name_const(ptr, ptr)

char *talloc_asprintf_append(char *s, const char *fmt, ...);

- The talloc_asprintf_append() function appends the given formatted - string to the given string. -

(type *)talloc_array(const void *ctx, type, uint_t count);

- The talloc_array() macro is equivalent to: - 

(type *)talloc_size(ctx, sizeof(type) * count);

- except that it provides integer overflow protection for the - multiply, returning NULL if the multiply overflows. -

void *talloc_array_size(const void *ctx, size_t size, uint_t count);

- The talloc_array_size() function is useful when the type is not - known. It operates in the same way as talloc_array(), but takes a - size instead of a type. -

(typeof(ptr)) talloc_array_ptrtype(const void *ctx, ptr, uint_t count);

- The talloc_ptrtype() macro should be used when you have a pointer to an array - and want to allocate memory of an array to point at with this pointer. When compiling - with gcc >= 3 it is typesafe. Note this is a wrapper of talloc_array_size() - and talloc_get_name() will return the current location in the source file. - and not the type. -

void *talloc_realloc_fn(const void *ctx, void *ptr, size_t size)

- This is a non-macro version of talloc_realloc(), which is useful - as libraries sometimes want a realloc function pointer. A - realloc(3) implementation encapsulates the functionality of - malloc(3), free(3) and realloc(3) in one call, which is why it is - useful to be able to pass around a single function pointer. -

void *talloc_autofree_context(void);

- This is a handy utility function that returns a talloc context - which will be automatically freed on program exit. This can be - used to reduce the noise in memory leak reports. -

void *talloc_check_name(const void *ptr, const char *name);

- This function checks if a pointer has the specified name. If it does then the pointer is - returned. It it doesn't then NULL is returned. -

(type *)talloc_get_type(const void *ptr, type);

- This macro allows you to do type checking on talloc pointers. It - is particularly useful for void* private pointers. It is - equivalent to this: - 

(type *)talloc_check_name(ptr, #type)

talloc_set_type(const void *ptr, type);

- This macro allows you to force the name of a pointer to be a - particular type. This can be - used in conjunction with talloc_get_type() to do type checking on - void* pointers. -

- It is equivalent to this: - 

talloc_set_name_const(ptr, #type)

PERFORMANCE

- All the additional features of talloc(3) over malloc(3) do come at a - price. We have a simple performance test in Samba4 that measures - talloc() versus malloc() performance, and it seems that talloc() is - about 10% slower than malloc() on my x86 Debian Linux box. For - Samba, the great reduction in code complexity that we get by using - talloc makes this worthwhile, especially as the total overhead of - talloc/malloc in Samba is already quite small. -

SEE ALSO

- malloc(3), strndup(3), vasprintf(3), asprintf(3), - http://talloc.samba.org/ -

COPYRIGHT/LICENSE

- Copyright (C) Andrew Tridgell 2004 -

- This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 3 of the License, or (at - your option) any later version. -

- This program is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - General Public License for more details. -

- You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. -

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