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[mod_cgi] reuse chunk buffers 

reuse chunk buffers rather than persistent allocated memory
(reduce possibility of long-term memory fragmentation due to mod_cgi)
personal/stbuehler/tests-path
Glenn Strauss 2021-07-31 13:36:52 -04:00
parent 55d8ed1b25
commit 7b3a4f13d7
1 changed files with 41 additions and 37 deletions
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78
src/mod_cgi.c
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@ -40,14 +40,11 @@ static int pipe_cloexec(int pipefd[2]) {
}
typedef struct {
char *ptr;
size_t used;
size_t size;
size_t *offsets;
uintptr_t *offsets;
size_t osize;
size_t oused;
char **eptr;
size_t esize;
buffer *b;
buffer *boffsets;
buffer *ld_preload;
buffer *ld_library_path;
#ifdef __CYGWIN__
@ -147,9 +144,6 @@ FREE_FUNC(mod_cgi_free) {
plugin_data *p = p_d;
buffer_pid_t *bp = &(p->cgi_pid);
if (bp->ptr) free(bp->ptr);
free(p->env.ptr);
free(p->env.offsets);
free(p->env.eptr);
buffer_free(p->env.ld_preload);
buffer_free(p->env.ld_library_path);
#ifdef __CYGWIN__
@ -556,33 +550,29 @@ static handler_t cgi_handle_fdevent(void *ctx, int revents) {
}
__attribute_cold__
__attribute_noinline__
static void cgi_env_offset_resize(env_accum *env) {
chunk_buffer_prepare_append(env->boffsets, env->boffsets->size*2);
env->offsets = (uintptr_t *)(void *)env->boffsets->ptr;
env->osize = env->boffsets->size/sizeof(*env->offsets);
}
static int cgi_env_add(void *venv, const char *key, size_t key_len, const char *val, size_t val_len) {
env_accum *env = venv;
char *dst;
if (!key || (!val && val_len)) return -1;
if (env->size - env->used < key_len + val_len + 2) {
if (0 == env->size) env->size = 4096;
do { env->size *= 2; } while (env->size - env->used < key_len + val_len + 2);
env->ptr = realloc(env->ptr, env->size);
force_assert(env->ptr);
}
if (__builtin_expect( (env->osize == env->oused), 0))
cgi_env_offset_resize(env);
env->offsets[env->oused++] = env->b->used-1;
dst = env->ptr + env->used;
char * const dst = buffer_extend(env->b, key_len + val_len + 2);
memcpy(dst, key, key_len);
dst[key_len] = '=';
if (val_len) memcpy(dst + key_len + 1, val, val_len);
dst[key_len + 1 + val_len] = '\0';
if (env->osize == env->oused) {
env->osize += 16;
env->offsets = realloc(env->offsets, env->osize * sizeof(*env->offsets));
force_assert(env->offsets);
}
env->offsets[env->oused++] = env->used;
env->used += key_len + val_len + 2;
return 0;
}
@ -697,11 +687,16 @@ static int cgi_create_env(request_st * const r, plugin_data * const p, handler_c
return -1;
}
env_accum * const env = &p->env;
env->b = chunk_buffer_acquire();
env->boffsets = chunk_buffer_acquire();
buffer_truncate(env->b, 0);
char **envp;
{
size_t i = 0;
http_cgi_opts opts = { 0, 0, NULL, NULL };
env_accum *env = &p->env;
env->used = 0;
env->offsets = (uintptr_t *)(void *)env->boffsets->ptr;
env->osize = env->boffsets->size/sizeof(*env->offsets);
env->oused = 0;
/* create environment */
@ -722,15 +717,16 @@ static int cgi_create_env(request_st * const r, plugin_data * const p, handler_c
}
#endif
if (env->esize <= env->oused) {
env->esize = (env->oused + 1 + 0xf) & ~(0xfuL);
env->eptr = realloc(env->eptr, env->esize * sizeof(*env->eptr));
force_assert(env->eptr);
}
for (i = 0; i < env->oused; ++i) {
env->eptr[i] = env->ptr + env->offsets[i];
}
env->eptr[env->oused] = NULL;
/* adjust (uintptr_t) offsets to (char *) ptr
* (stored as offsets while accumulating in buffer,
* in case buffer is reallocated during env creation) */
if (__builtin_expect( (env->osize == env->oused), 0))
cgi_env_offset_resize(env);
envp = (char **)env->offsets;
envp[env->oused] = NULL;
const uintptr_t baseptr = (uintptr_t)env->b->ptr;
for (i = 0; i < env->oused; ++i)
envp[i] += baseptr;
/* set up args */
i = 0;
@ -748,7 +744,15 @@ static int cgi_create_env(request_st * const r, plugin_data * const p, handler_c
}
int serrh_fd = r->conf.serrh ? r->conf.serrh->errorlog_fd : -1;
hctx->pid = (dfd >= 0) ? fdevent_fork_execve(args[0], args, p->env.eptr, to_cgi_fds[0], from_cgi_fds[1], serrh_fd, dfd) : -1;
hctx->pid = (dfd >= 0)
? fdevent_fork_execve(args[0], args, envp,
to_cgi_fds[0], from_cgi_fds[1], serrh_fd, dfd)
: -1;
chunk_buffer_release(env->boffsets);
chunk_buffer_release(env->b);
env->boffsets = NULL;
env->b = NULL;
if (-1 == hctx->pid) {
/* log error with errno prior to calling close() (might change errno) */