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[mod_cgi] use linked list for process list

(avoids persistent memory allocation for list struct)
(reduce possibility of long-term memory fragmentation due to mod_cgi)
master
Glenn Strauss 3 months ago
parent
commit
7e000de04e
  1. 108
      src/mod_cgi.c

108
src/mod_cgi.c

@ -52,12 +52,6 @@ typedef struct {
#endif
} env_accum;
typedef struct {
struct { pid_t pid; void *ctx; } *ptr;
size_t used;
size_t size;
} buffer_pid_t;
typedef struct {
unix_time64_t read_timeout;
unix_time64_t write_timeout;
@ -73,16 +67,18 @@ typedef struct {
const array *xsendfile_docroot;
} plugin_config;
struct cgi_pid_t;
typedef struct {
PLUGIN_DATA;
plugin_config defaults;
plugin_config conf;
buffer_pid_t cgi_pid;
struct cgi_pid_t *cgi_pid;
env_accum env;
} plugin_data;
typedef struct {
pid_t pid;
struct cgi_pid_t *cgi_pid;
int fd;
int fdtocgi;
fdnode *fdn;
@ -100,6 +96,13 @@ typedef struct {
plugin_config conf;
} handler_ctx;
typedef struct cgi_pid_t {
pid_t pid;
handler_ctx *hctx;
struct cgi_pid_t *next;
struct cgi_pid_t *prev;
} cgi_pid_t;
static handler_ctx * cgi_handler_ctx_init(void) {
handler_ctx *hctx = calloc(1, sizeof(*hctx));
@ -142,14 +145,17 @@ INIT_FUNC(mod_cgi_init) {
FREE_FUNC(mod_cgi_free) {
plugin_data *p = p_d;
buffer_pid_t *bp = &(p->cgi_pid);
if (bp->ptr) free(bp->ptr);
buffer_free(p->env.ld_preload);
buffer_free(p->env.ld_library_path);
#ifdef __CYGWIN__
buffer_free(p->env.systemroot);
#endif
for (cgi_pid_t *cgi_pid = p->cgi_pid, *next; cgi_pid; cgi_pid = next) {
next = cgi_pid->next;
free(cgi_pid);
}
if (NULL == p->cvlist) return;
/* (init i to 0 if global context; to 1 to skip empty global context) */
for (int i = !p->cvlist[0].v.u2[1], used = p->nconfig; i < used; ++i) {
@ -311,38 +317,32 @@ SETDEFAULTS_FUNC(mod_cgi_set_defaults) {
}
static void cgi_pid_add(plugin_data *p, pid_t pid, void *ctx) {
buffer_pid_t *bp = &(p->cgi_pid);
if (bp->used == bp->size) {
bp->size += 16;
bp->ptr = realloc(bp->ptr, sizeof(*bp->ptr) * bp->size);
force_assert(bp->ptr);
}
bp->ptr[bp->used].pid = pid;
bp->ptr[bp->used].ctx = ctx;
++bp->used;
static cgi_pid_t * cgi_pid_add(plugin_data *p, pid_t pid, handler_ctx *hctx) {
cgi_pid_t *cgi_pid = malloc(sizeof(cgi_pid_t));
force_assert(cgi_pid);
cgi_pid->pid = pid;
cgi_pid->hctx = hctx;
cgi_pid->prev = NULL;
cgi_pid->next = p->cgi_pid;
p->cgi_pid = cgi_pid;
return cgi_pid;
}
static void cgi_pid_kill(plugin_data *p, pid_t pid) {
buffer_pid_t *bp = &(p->cgi_pid);
for (size_t i = 0; i < bp->used; ++i) {
if (bp->ptr[i].pid == pid) {
bp->ptr[i].ctx = NULL;
kill(pid, SIGTERM);
return;
}
}
static void cgi_pid_kill(cgi_pid_t *cgi_pid) {
cgi_pid->hctx = NULL;
kill(cgi_pid->pid, SIGTERM);
}
static void cgi_pid_del(plugin_data *p, size_t i) {
buffer_pid_t *bp = &(p->cgi_pid);
static void cgi_pid_del(plugin_data *p, cgi_pid_t *cgi_pid) {
if (cgi_pid->prev)
cgi_pid->prev->next = cgi_pid->next;
else
p->cgi_pid = cgi_pid->next;
if (i != bp->used - 1)
bp->ptr[i] = bp->ptr[bp->used - 1];
if (cgi_pid->next)
cgi_pid->next->prev = cgi_pid->prev;
--bp->used;
free(cgi_pid);
}
@ -377,15 +377,11 @@ static void cgi_connection_close(handler_ctx *hctx) {
}
plugin_data * const p = hctx->plugin_data;
if (hctx->pid > 0) {
cgi_pid_kill(p, hctx->pid);
}
request_st * const r = hctx->r;
r->plugin_ctx[p->id] = NULL;
if (hctx->cgi_pid)
cgi_pid_kill(hctx->cgi_pid);
cgi_handler_ctx_free(hctx);
/* finish response (if not already r->resp_body_started, r->resp_body_finished) */
@ -744,7 +740,7 @@ 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)
pid_t pid = (dfd >= 0)
? fdevent_fork_execve(args[0], args, envp,
to_cgi_fds[0], from_cgi_fds[1], serrh_fd, dfd)
: -1;
@ -754,7 +750,7 @@ static int cgi_create_env(request_st * const r, plugin_data * const p, handler_c
env->boffsets = NULL;
env->b = NULL;
if (-1 == hctx->pid) {
if (-1 == pid) {
/* log error with errno prior to calling close() (might change errno) */
log_perror(r->conf.errh, __FILE__, __LINE__, "fork failed");
if (-1 != dfd) close(dfd);
@ -769,8 +765,7 @@ static int cgi_create_env(request_st * const r, plugin_data * const p, handler_c
close(to_cgi_fds[0]);
hctx->fd = from_cgi_fds[0];
cgi_pid_add(p, hctx->pid, hctx);
hctx->cgi_pid = cgi_pid_add(p, pid, hctx);
if (0 == r->reqbody_length) {
close(to_cgi_fds[1]);
@ -952,7 +947,7 @@ static void cgi_trigger_hctx_timeout(handler_ctx * const hctx, const char * cons
log_error(r->conf.errh, __FILE__, __LINE__,
"%s timeout on CGI: %s (pid: %lld)",
msg, r->physical.path.ptr, (long long)hctx->pid);
msg, r->physical.path.ptr, (long long)hctx->cgi_pid->pid);
if (*msg == 'w') { /* "write" */
/* theoretically, response might be waiting on hctx->fdn pipe
@ -970,11 +965,11 @@ static void cgi_trigger_hctx_timeout(handler_ctx * const hctx, const char * cons
static handler_t cgi_trigger_cb(server *srv, void *p_d) {
UNUSED(srv);
const unix_time64_t mono = log_monotonic_secs;
const buffer_pid_t * const cgi_pid = &((plugin_data *)p_d)->cgi_pid;
for (size_t i = 0, used = cgi_pid->used; i < used; ++i) {
plugin_data * const p = p_d;
for (cgi_pid_t *cgi_pid = p->cgi_pid; cgi_pid; cgi_pid = cgi_pid->next) {
/*(hctx stays in cgi_pid list until process pid is reaped,
* so p->cgi_pid[] is not modified during this loop)*/
handler_ctx * const hctx = (handler_ctx *)cgi_pid->ptr[i].ctx;
handler_ctx * const hctx = cgi_pid->hctx;
if (!hctx) continue; /*(already called cgi_pid_kill())*/
const cgi_limits * const limits = hctx->conf.limits;
if (NULL == limits) continue;
@ -996,14 +991,15 @@ static handler_t cgi_trigger_cb(server *srv, void *p_d) {
static handler_t cgi_waitpid_cb(server *srv, void *p_d, pid_t pid, int status) {
/*(XXX: if supporting a large number of CGI, might use a different algorithm
* instead of linked list, e.g. splaytree indexed with pid)*/
plugin_data *p = (plugin_data *)p_d;
for (size_t i = 0; i < p->cgi_pid.used; ++i) {
handler_ctx *hctx;
if (pid != p->cgi_pid.ptr[i].pid) continue;
for (cgi_pid_t *cgi_pid = p->cgi_pid; cgi_pid; cgi_pid = cgi_pid->next) {
if (pid != cgi_pid->pid) continue;
hctx = (handler_ctx *)p->cgi_pid.ptr[i].ctx;
if (hctx) hctx->pid = -1;
cgi_pid_del(p, i);
handler_ctx * const hctx = cgi_pid->hctx;
if (hctx) hctx->cgi_pid = NULL;
cgi_pid_del(p, cgi_pid);
if (WIFEXITED(status)) {
/* (skip logging (non-zero) CGI exit; might be very noisy) */

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