proxychains-ng/src/shm.h

#ifndef SHM_H
#define SHM_H
#include <unistd.h>

struct stringpool {
	size_t alloced;
	size_t used;
	char* start;
};

void stringpool_init(struct stringpool* sp);
char* stringpool_add(struct stringpool *sp, char* s, size_t len);
#if 0
void *shm_realloc(void* old, size_t old_size, size_t new_size);
#endif
//RcB: DEP "shm.c"
#endif
use mutexes also to protect the pipe communication wasn't threadsafe before. 2012-11-08 04:11:03 +08:00			`#ifndef SHM_H`
			`#define SHM_H`
failed attempt to use shared memory for the ip <-> dns mapping this is in order to get irssi, which forks for DNS lookups, and similar programs, to work as intended. in a previous attempt i learned that shared memory created in a child process is not visible to the parent; in this attempt i spin off a thread from the parent which listens on a pipe and manages the shared memory allocation from the parent address-space. however this doesnt work as expected: memory allocated in the parent after the child forked is not visi- ble to the child as well. so what happens is: irssi starts a child process, the thread allocs memory and hands it to the child, the child attempts to write and segfaults. however irssi doesnt crash. since now the memory is already allocated, doing the dns lookup again will succeed. i.e. the dns lookup works now in irssi by luck. all but the first dns lookups will suceed. however this is not good enough for me to be satisfied, i commit this only for documentation purposes. 2012-11-07 23:49:14 +08:00			`#include <unistd.h>`

			`struct stringpool {`
			`size_t alloced;`
			`size_t used;`
			`char* start;`
			`};`

			`void stringpool_init(struct stringpool* sp);`
			`char* stringpool_add(struct stringpool sp, char s, size_t len);`
use mutexes also to protect the pipe communication wasn't threadsafe before. 2012-11-08 04:11:03 +08:00			`#if 0`
failed attempt to use shared memory for the ip <-> dns mapping this is in order to get irssi, which forks for DNS lookups, and similar programs, to work as intended. in a previous attempt i learned that shared memory created in a child process is not visible to the parent; in this attempt i spin off a thread from the parent which listens on a pipe and manages the shared memory allocation from the parent address-space. however this doesnt work as expected: memory allocated in the parent after the child forked is not visi- ble to the child as well. so what happens is: irssi starts a child process, the thread allocs memory and hands it to the child, the child attempts to write and segfaults. however irssi doesnt crash. since now the memory is already allocated, doing the dns lookup again will succeed. i.e. the dns lookup works now in irssi by luck. all but the first dns lookups will suceed. however this is not good enough for me to be satisfied, i commit this only for documentation purposes. 2012-11-07 23:49:14 +08:00			`void shm_realloc(void old, size_t old_size, size_t new_size);`
use mutexes also to protect the pipe communication wasn't threadsafe before. 2012-11-08 04:11:03 +08:00			`#endif`
failed attempt to use shared memory for the ip <-> dns mapping this is in order to get irssi, which forks for DNS lookups, and similar programs, to work as intended. in a previous attempt i learned that shared memory created in a child process is not visible to the parent; in this attempt i spin off a thread from the parent which listens on a pipe and manages the shared memory allocation from the parent address-space. however this doesnt work as expected: memory allocated in the parent after the child forked is not visi- ble to the child as well. so what happens is: irssi starts a child process, the thread allocs memory and hands it to the child, the child attempts to write and segfaults. however irssi doesnt crash. since now the memory is already allocated, doing the dns lookup again will succeed. i.e. the dns lookup works now in irssi by luck. all but the first dns lookups will suceed. however this is not good enough for me to be satisfied, i commit this only for documentation purposes. 2012-11-07 23:49:14 +08:00			`//RcB: DEP "shm.c"`
use mutexes also to protect the pipe communication wasn't threadsafe before. 2012-11-08 04:11:03 +08:00			`#endif`