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scgi-cgi/scgi-cgi.c

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C
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <event2/event.h>
#define MAX_BUFFER_SIZE (64u*1024u)
#define MAX_STRING_BUFFER_SIZE (64u*1024u) /* env keys and values */
#define CONST_STR_LEN(x) (x), sizeof(x) - 1
#define GSTR_LEN(x) (x) ? (x)->str : "", (x) ? (x)->len : 0
#define UNUSED(x) ((void)(x))
#ifdef __GNUC__
#define ATTR_WARN_UNUSED_RESULT \
__attribute__((warn_unused_result))
#define ATTR_FORMAT(fmt, args) \
__attribute__(( format(printf, fmt, args) ))
#else
#define ATTR_WARN_UNUSED_RESULT
#define ATTR_FORMAT(fmt, args)
#endif
#define ERROR(...) printerr(__LINE__, __VA_ARGS__)
#ifdef NDEBUG
# define DEBUG(...) do { } while (0)
#else
# define DEBUG(...) printerr(__LINE__, "DEBUG: " __VA_ARGS__)
#endif
#define PACKAGE_DESC PACKAGE_NAME " v" PACKAGE_VERSION " - SCGI application to run normal cgi applications"
/* force asserts to be enabled */
#undef NDEBUG
#include <assert.h>
/****************************************************************************
* logging *
***************************************************************************/
static void printerr(unsigned int line, const char *fmt, ...) ATTR_FORMAT(2, 3);
static void printerr(unsigned int line, const char *fmt, ...) {
va_list ap;
fprintf(stderr, "scgi-cgi.c:%u:", line);
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fprintf(stderr, "\n");
}
/****************************************************************************
* STRING BUFFER *
***************************************************************************/
typedef struct string_buffer string_buffer;
struct string_buffer {
/* always 0-terminated string (unless data == NULL), but don't count terminating 0 in `used' */
unsigned char *data;
unsigned int used, size;
};
static void string_buffer_init(string_buffer *buf);
static void string_buffer_clear(string_buffer *buf);
static unsigned char* string_buffer_extract(string_buffer *buf) ATTR_WARN_UNUSED_RESULT; /* resets buffer, returns string. free string with free() */
static int string_buffer_reserve(string_buffer *buf, unsigned int len) ATTR_WARN_UNUSED_RESULT;
static int string_buffer_append(string_buffer *buf, const unsigned char *data, unsigned int len) ATTR_WARN_UNUSED_RESULT;
static int string_buffer_append_char(string_buffer *buf, unsigned char c) ATTR_WARN_UNUSED_RESULT;
static int string_buffer_equal(string_buffer *buf, const char *data, unsigned int len);
#define STRING_BUFFER_EQUAL(buf, str) string_buffer_equal(buf, str, sizeof(str) - 1)
static void string_buffer_init(string_buffer *buf) {
buf->data = NULL;
buf->used = buf->size = 0;
}
static void string_buffer_clear(string_buffer *buf) {
if (NULL != buf->data) free(buf->data);
buf->data = NULL;
buf->used = buf->size = 0;
}
static unsigned char* string_buffer_extract(string_buffer *buf) {
unsigned char *str = buf->data;
string_buffer_init(buf);
return str;
}
static int string_buffer_reserve(string_buffer *buf, unsigned int len) {
assert(buf->used <= buf->size);
assert(buf->size <= MAX_STRING_BUFFER_SIZE);
if (1 > UINT_MAX - len || len + 1 > MAX_STRING_BUFFER_SIZE - buf->used) {
DEBUG("string buffer: overflow");
return 0;
}
unsigned int newlen = buf->used + len;
if (newlen + 1 > buf->size) {
unsigned int need_size = newlen + 1;
unsigned int want_size = (need_size + 127) & ~127; /* round up to next multiple of 128 */
unsigned char *newdata;
if (want_size < need_size) want_size = need_size; /* overflow handling */
newdata = (unsigned char*) realloc(buf->data, want_size);
if (NULL == newdata) {
DEBUG("string buffer: realloc failed");
return 0;
}
buf->data = newdata;
buf->size = want_size;
}
return 1;
}
static int string_buffer_append(string_buffer *buf, const unsigned char *data, unsigned int len) {
if (!string_buffer_reserve(buf, len)) return 0;
if (len > 0) memcpy(buf->data + buf->used, data, len);
buf->used += len;
buf->data[buf->used] = '\0';
return 1;
}
static int string_buffer_append_char(string_buffer *buf, unsigned char c) {
if (!string_buffer_reserve(buf, 1)) return 0;
buf->data[buf->used++] = c;
buf->data[buf->used] = '\0';
return 1;
}
static int string_buffer_equal(string_buffer *buf, const char *data, unsigned int len) {
if (buf->used != len) return 0;
if (0 == len) return 1;
return 0 == memcmp(buf->data, data, len);
}
/****************************************************************************
* SCGI PARSER *
***************************************************************************/
typedef enum scgi_req_parser_state {
SCGI_REQ_PARSER_HEADER_LEN,
SCGI_REQ_PARSER_HEADER_ENV_KEY,
SCGI_REQ_PARSER_HEADER_ENV_VALUE,
SCGI_REQ_PARSER_HEADER_DONE,
SCGI_REQ_PARSER_HEADER_ERROR
} scgi_req_parser_state;
typedef struct scgi_req_parser scgi_req_parser;
struct scgi_req_parser {
scgi_req_parser_state state;
unsigned int header_length, is_scgi;
unsigned long long content_length;
unsigned char **environ; /* list terminated by NULL entry */
unsigned int environ_used, environ_size;
string_buffer key_value;
unsigned int key_length;
};
static int key_value_has_key(scgi_req_parser *parser, char *key, unsigned int keylen);
static void scgi_parser_init(scgi_req_parser *parser);
static void scgi_parser_clear(scgi_req_parser *parser);
static void scgi_parser_clear_environment(scgi_req_parser *parser);
static int scgi_parser_environ_reserve(scgi_req_parser *parser);
static int scgi_parser_environ_append(scgi_req_parser *parser, unsigned char *kvstr, int keylength);
static int scgi_parser_environ_copy(scgi_req_parser *parser, const char *key, unsigned int keylength);
static const char* scgi_parser_environ_get(scgi_req_parser *parser, const char *key, unsigned int keylength);
static int scgi_parse(scgi_req_parser *parser, unsigned char *data, int len) ATTR_WARN_UNUSED_RESULT;
static int key_value_has_key(scgi_req_parser *parser, char *key, unsigned int keylen) {
if (parser->key_length != keylen) return 0;
return 0 == memcmp(parser->key_value.data, key, keylen);
}
#define KEY_VALUE_HAS_KEY(parser, key) key_value_has_key(parser, key, sizeof(key) - 1)
static void scgi_parser_init(scgi_req_parser *parser) {
parser->state = SCGI_REQ_PARSER_HEADER_LEN;
parser->header_length = parser->content_length = parser->is_scgi = 0;
parser->environ = NULL;
parser->environ_used = parser->environ_size = 0;
string_buffer_init(&parser->key_value);
parser->key_length = 0;
}
static void scgi_parser_clear(scgi_req_parser *parser) {
unsigned int i;
for (i = 0; i < parser->environ_used; ++i) {
free(parser->environ[i]);
}
free(parser->environ);
string_buffer_clear(&parser->key_value);
parser->state = SCGI_REQ_PARSER_HEADER_LEN;
parser->header_length = parser->content_length = parser->is_scgi = 0;
parser->environ = NULL;
parser->environ_used = parser->environ_size = 0;
parser->key_length = 0;
}
static void scgi_parser_clear_environment(scgi_req_parser *parser) {
unsigned int i;
for (i = 0; i < parser->environ_used; ++i) {
free(parser->environ[i]);
}
free(parser->environ);
parser->environ = NULL;
parser->environ_used = parser->environ_size = 0;
}
static int scgi_parser_environ_reserve(scgi_req_parser *parser) {
if (2 > UINT_MAX/sizeof(unsigned char*) - parser->environ_used) {
DEBUG("scgi environment: entries overflow");
return 0; /* overflow: can't append */
}
if (parser->environ_used + 2 > parser->environ_size) {
unsigned int need_size = sizeof(unsigned char*) * (parser->environ_used + 2);
unsigned int want_size = (need_size + 1024) & ~1023; /* round up to next multiple of 1023 (for 8-byte pointers: 128 entries) */
unsigned char **newdata;
if (want_size < need_size) want_size = need_size; /* overflow handling */
newdata = (unsigned char**) realloc(parser->environ, want_size);
if (NULL == newdata) {
DEBUG("scgi environment: realloc failed");
return 0; /* ENOMEM */
}
parser->environ = newdata;
parser->environ_size = want_size / sizeof(unsigned char*);
}
return 1;
}
/* kvstr: "KEY=VALUE", keylength = strlen("KEY")
* return values: 0: not appended: key already exists (not overwriting), or some other error; 1: appended
* kvstr is free()d if it wasn't appended.
*/
static int scgi_parser_environ_append(scgi_req_parser *parser, unsigned char *kvstr, int keylength) {
unsigned int i;
for (i = 0; i < parser->environ_used; ++i) {
const char *e = (const char*) parser->environ[i];
if (0 == strncmp(e, (const char *) kvstr, keylength + 1)) {
DEBUG("scgi req header: duplicate key for entry '%s', already have '%s'", kvstr, e);
goto fail; /* found */
}
}
if (!scgi_parser_environ_reserve(parser)) goto fail;
parser->environ[parser->environ_used++] = kvstr;
parser->environ[parser->environ_used] = NULL;
return 1;
fail:
free(kvstr);
return 0;
}
static int scgi_parser_environ_copy(scgi_req_parser *parser, const char *key, unsigned int keylength) {
const char *val = getenv(key);
unsigned int vallen;
unsigned char *kvstr;
unsigned int i;
if (NULL == val) return 1;
vallen = strlen(val);
kvstr = malloc(keylength + 2 + vallen);
if (NULL == kvstr) return 0;
memcpy(kvstr, key, keylength);
kvstr[keylength] = '=';
memcpy(kvstr + keylength + 1, val, vallen + 1);
for (i = 0; i < parser->environ_used; ++i) {
const char *e = (const char*) parser->environ[i];
if (0 == strncmp(e, (const char *) kvstr, keylength + 1)) {
/* found. overwrite: */
free(parser->environ[i]);
parser->environ[i] = kvstr;
}
}
if (!scgi_parser_environ_reserve(parser)) {
free(kvstr);
return 0;
}
parser->environ[parser->environ_used++] = kvstr;
parser->environ[parser->environ_used] = NULL;
return 1;
}
static const char* scgi_parser_environ_get(scgi_req_parser *parser, const char *key, unsigned int keylength) {
unsigned int i;
for (i = 0; i < parser->environ_used; ++i) {
const char *e = (const char*) parser->environ[i];
if (0 == strncmp(e, (const char *) key, keylength) && '=' == e[keylength]) {
return (const char*) e + keylength + 1;
}
}
return NULL;
}
/* return values:
* -2: error
* -1: need more data for header
* l>=0: trailing l bytes of data are request body data; header finished.
*/
static int scgi_parse(scgi_req_parser *parser, unsigned char *data, int len) {
assert(len > 0);
for (; len > 0; ++data, --len) {
unsigned char c = *data;
switch (parser->state) {
case SCGI_REQ_PARSER_HEADER_LEN:
{
unsigned int digit;
if (c == ':') {
/* require at least 'CONTENT_LENGTH=0;SCGI=1;' in header ('=' and ';' encoded as '\0') */
if (parser->header_length < 24) {
DEBUG("scgi req header too small: %u", parser->header_length);
goto fail;
}
parser->state = SCGI_REQ_PARSER_HEADER_ENV_KEY;
break;
}
if (c < '0' || c > '9') {
DEBUG("scgi req header: expected digit or ':' in header length, got '%c'", c);
goto fail;
}
if (0 == parser->header_length && c == '0') {
/* extra leading zeroes are prohibited; zero header length is not permitted either:
* require CONTENT_LENGTH and SCGI vars
* => starting 0 digit is never allowed
*/
DEBUG("scgi req header: header length starting with 0");
goto fail;
}
digit = c - '0';
if (parser->header_length > UINT_MAX / 10 - digit) {
DEBUG("scgi req header: header length overflow");
goto fail; /* overflow */
}
parser->header_length = 10*parser->header_length + digit;
}
break;
case SCGI_REQ_PARSER_HEADER_ENV_KEY:
if (0 == parser->header_length) {
if (',' != c) {
DEBUG("scgi req header: require ',' before request body, got '%c'", c);
goto fail; /* after header require a ',' */
}
if (0 != parser->key_value.used) {
DEBUG("scgi req header: headers ended with partial key '%s'", parser->key_value.data);
goto fail; /* partial header on headers end */
}
if (!parser->is_scgi) {
DEBUG("scgi req header: missing SCGI=1");
goto fail; /* is_scgi is only set after CONTENT_LENGTH (always first header) is parsed, and then SCGI=1 was found */
}
parser->state = SCGI_REQ_PARSER_HEADER_DONE;
return len - 1;
}
--parser->header_length;
if (0 != c) {
if ('=' == c) {
DEBUG("scgi req header: key must not include '='");
goto fail; /* '=' can't be allowed in keys */
}
if (!string_buffer_append_char(&parser->key_value, c)) goto fail;
break;
}
/* key end */
parser->key_length = parser->key_value.used;
if (!string_buffer_append_char(&parser->key_value, '=')) goto fail;
parser->state = SCGI_REQ_PARSER_HEADER_ENV_VALUE;
break;
case SCGI_REQ_PARSER_HEADER_ENV_VALUE:
if (0 == parser->header_length) {
DEBUG("scgi req header: headers ended with partial value '%s'", parser->key_value.data);
goto fail; /* partial header on headers end */
}
--parser->header_length;
if (0 != c) {
int vallen = 1;
while (vallen < len && 0 != data[vallen]) ++vallen;
if (!string_buffer_append(&parser->key_value, data, vallen)) goto fail;
data += (vallen - 1);
len -= (vallen - 1);
parser->header_length -= (vallen - 1);
break;
}
/* value end */
if (0 == parser->environ_used) {
long long clen;
char *endptr = NULL, *startptr = (char*) parser->key_value.data + parser->key_length + 1;
if (!KEY_VALUE_HAS_KEY(parser, "CONTENT_LENGTH")) {
DEBUG("scgi req header: first header isn't CONTENT_LENGTH: '%s'", parser->key_value.data);
goto fail; /* first entry must be CONTENT_LENGTH */
}
if (parser->key_value.used == parser->key_length + 1) {
DEBUG("scgi req header: CONTENT_LENGTH is empty");
goto fail; /* empty CONTENT_LENGTH */
}
errno = 0;
clen = strtoll(startptr, &endptr, 10);
if (0 != errno) {
DEBUG("scgi req header: parsing '%s' failed: %s", parser->key_value.data, strerror(errno));
goto fail;
}
if (endptr != (char*) parser->key_value.data + parser->key_value.used) {
DEBUG("scgi req header: parsing '%s' failed: contained more than number", parser->key_value.data);
goto fail; /* number didn't cover complete value */
}
if (clen < 0) {
DEBUG("scgi req header: parsing '%s' failed: negative length", parser->key_value.data);
goto fail; /* number didn't cover complete value */
}
parser->content_length = (unsigned long long) clen;
} else if (KEY_VALUE_HAS_KEY(parser, "SCGI")) {
if (STRING_BUFFER_EQUAL(&parser->key_value, "SCGI=1")) {
parser->is_scgi = 1;
} else {
DEBUG("scgi req header: SCGI is not 1: '%s'", parser->key_value.data);
goto fail; /* SCGI must be 1 */
}
}
if (!scgi_parser_environ_append(parser, string_buffer_extract(&parser->key_value), parser->key_length)) goto fail; /* duplicate key / ENOMEM */
parser->key_length = 0;
parser->state = SCGI_REQ_PARSER_HEADER_ENV_KEY;
break;
case SCGI_REQ_PARSER_HEADER_DONE:
return len;
case SCGI_REQ_PARSER_HEADER_ERROR:
goto fail;
}
}
return -1;
fail:
parser->state = SCGI_REQ_PARSER_HEADER_ERROR;
return -2;
}
/****************************************************************************
* SCGI RING BUFFERS *
***************************************************************************/
/* ring buffer */
typedef struct scgi_cgi_buffer scgi_cgi_buffer;
struct scgi_cgi_buffer {
unsigned int pos, len;
unsigned char data[MAX_BUFFER_SIZE];
};
static void scgi_buffer_input_location(scgi_cgi_buffer *buf, unsigned char **location, ssize_t *location_size);
static void scgi_buffer_fill(scgi_cgi_buffer *buf, ssize_t n);
static void scgi_buffer_output_location(scgi_cgi_buffer *buf, unsigned char **location, ssize_t *location_size);
static void scgi_buffer_drain(scgi_cgi_buffer *buf, ssize_t n);
static int scgi_buffer_is_input_open(scgi_cgi_buffer *buf);
static void scgi_buffer_set(scgi_cgi_buffer *buf, const char *data, ssize_t len);
#define SCGI_BUFFER_SET(buf, str) scgi_buffer_set(buf, str, sizeof(str)-1)
static void scgi_buffer_input_location(scgi_cgi_buffer *buf, unsigned char **location, ssize_t *location_size) {
if (buf->pos + buf->len >= MAX_BUFFER_SIZE) {
*location = buf->data + (buf->pos + buf->len - MAX_BUFFER_SIZE);
*location_size = MAX_BUFFER_SIZE - buf->len;
} else {
*location = buf->data + (buf->pos + buf->len);
*location_size = MAX_BUFFER_SIZE - (buf->pos + buf->len);
}
}
static void scgi_buffer_fill(scgi_cgi_buffer *buf, ssize_t n) {
assert(n >= 0 && (unsigned int) n <= MAX_BUFFER_SIZE - buf->len);
buf->len += n;
}
static void scgi_buffer_output_location(scgi_cgi_buffer *buf, unsigned char **location, ssize_t *location_size) {
*location = buf->data + buf->pos;
if (buf->pos + buf->len >= MAX_BUFFER_SIZE) {
*location_size = MAX_BUFFER_SIZE - buf->pos;
} else {
*location_size = buf->len;
}
}
static void scgi_buffer_drain(scgi_cgi_buffer *buf, ssize_t n) {
assert(n >= 0 && (unsigned int) n <= buf->len);
buf->pos = (buf->pos + n) % MAX_BUFFER_SIZE;
buf->len -= n;
if (0 == buf->len) buf->pos = 0;
}
static int scgi_buffer_is_input_open(scgi_cgi_buffer *buf) {
return buf->len < MAX_BUFFER_SIZE;
}
static void scgi_buffer_set(scgi_cgi_buffer *buf, const char *data, ssize_t len) {
assert(len >= 0 && len <= MAX_BUFFER_SIZE);
memcpy(buf->data, data, len);
buf->pos = 0;
buf->len = len;
}
/****************************************************************************
* SCGI CHILD + SERVER *
***************************************************************************/
typedef struct scgi_cgi_server scgi_cgi_server;
typedef struct scgi_cgi_child scgi_cgi_child;
struct scgi_cgi_server {
struct event_base *base;
struct event *listen_watcher;
struct event
*sig_w_CHLD,
*sig_w_INT,
*sig_w_TERM,
*sig_w_HUP;
const char *binary;
unsigned int children_used, children_size;
scgi_cgi_child **children;
};
struct scgi_cgi_child {
unsigned int ndx;
scgi_cgi_server *srv;
struct event *sock_in_watcher, *sock_out_watcher;
scgi_req_parser req_parser;
pid_t pid;
int child_stdout, child_stdin;
struct event *pipe_in_watcher, *pipe_out_watcher;
scgi_cgi_buffer request_buf;
scgi_cgi_buffer response_buf;
};
static void fd_init(int fd);
static void _my_event_free_with_fd(struct event **event);
static void _my_event_free(struct event **event);
#define MY_EVENT_FREE_WITH_FD(event) _my_event_free_with_fd(&(event))
#define MY_EVENT_FREE(event) _my_event_free(&(event))
static scgi_cgi_child* scgi_cgi_child_create(scgi_cgi_server *srv, int fd);
static void scgi_cgi_child_free(scgi_cgi_child *cld);
static void scgi_cgi_child_check_done(scgi_cgi_child *cld);
static void scgi_cgi_child_exec(scgi_cgi_child *cld);
static void scgi_cgi_child_start(scgi_cgi_child *cld);
static void scgi_cgi_close_socket(scgi_cgi_child *cld);
static void scgi_cgi_child_sock_in_cb(evutil_socket_t fd, short what, void *arg);
static void scgi_cgi_child_sock_out_cb(evutil_socket_t fd, short what, void *arg);
static void scgi_cgi_child_pipe_in_cb(evutil_socket_t fd, short what, void *arg);
static void scgi_cgi_child_pipe_out_cb(evutil_socket_t fd, short what, void *arg);
static scgi_cgi_server* scgi_cgi_server_create(int fd, const char *binary, unsigned int maxconns);
static void scgi_cgi_server_free(scgi_cgi_server* srv);
static void scgi_cgi_server_child_finished(scgi_cgi_server *srv, scgi_cgi_child *cld);
static void scgi_cgi_server_accept(evutil_socket_t fd, short what, void *arg);
static void sigint_cb(evutil_socket_t fd, short what, void *arg);
static void sigchld_cb(evutil_socket_t fd, short what, void *arg);
/****************************************************************************
* SCGI utils implementation *
***************************************************************************/
static void fd_init(int fd) {
#ifdef _WIN32
int i = 1;
#endif
#ifdef FD_CLOEXEC
/* close fd on exec (cgi) */
fcntl(fd, F_SETFD, FD_CLOEXEC);
#endif
#ifdef O_NONBLOCK
fcntl(fd, F_SETFL, O_NONBLOCK | O_RDWR);
#elif defined _WIN32
ioctlsocket(fd, FIONBIO, &i);
#endif
}
static void _my_event_free_with_fd(struct event **event) {
int fd;
if (NULL == *event) return;
fd = event_get_fd(*event);
event_free(*event);
*event = NULL;
if (-1 != fd) close(fd);
}
static void _my_event_free(struct event **event) {
if (NULL == *event) return;
event_free(*event);
*event = NULL;
}
/****************************************************************************
* SCGI CHILD implementation *
***************************************************************************/
static scgi_cgi_child* scgi_cgi_child_create(scgi_cgi_server *srv, int fd) {
struct event_base *base = srv->base;
scgi_cgi_child *cld;
int pipe_stdout[2], pipe_stdin[2];
if (-1 == pipe(pipe_stdout)) {
ERROR("couldn't create pipe: %s", strerror(errno));
return NULL;
}
if (-1 == pipe(pipe_stdin)) {
ERROR("couldn't create pipe: %s", strerror(errno));
close(pipe_stdout[0]); close(pipe_stdout[1]); return NULL;
}
cld = calloc(1, sizeof(scgi_cgi_child));
if (NULL == cld) {
ERROR("couldn't alloc: %s", strerror(errno));
close(pipe_stdout[0]); close(pipe_stdout[1]); close(pipe_stdin[0]); close(pipe_stdin[1]); return NULL;
}
cld->srv = srv;
cld->pid = -1;
cld->child_stdin = pipe_stdin[0];
cld->child_stdout = pipe_stdout[1];
scgi_parser_init(&cld->req_parser);
cld->sock_in_watcher = event_new(base, fd, EV_READ | EV_PERSIST, scgi_cgi_child_sock_in_cb, cld);
cld->sock_out_watcher = event_new(base, fd, EV_WRITE | EV_PERSIST, scgi_cgi_child_sock_out_cb, cld);
fd_init(pipe_stdin[1]);
cld->pipe_out_watcher = event_new(base, pipe_stdin[1], EV_WRITE | EV_PERSIST, scgi_cgi_child_pipe_out_cb, cld);
fd_init(pipe_stdout[0]);
cld->pipe_in_watcher = event_new(base, pipe_stdout[0], EV_READ | EV_PERSIST, scgi_cgi_child_pipe_in_cb, cld);
if (NULL == cld->sock_in_watcher || NULL == cld->sock_out_watcher || NULL == cld->pipe_in_watcher || NULL == cld->pipe_out_watcher) {
ERROR("couldn't alloc: %s", strerror(errno));
if (NULL == cld->pipe_in_watcher) close(pipe_stdin[1]);
if (NULL == cld->pipe_out_watcher) close(pipe_stdout[0]);
scgi_cgi_child_free(cld);
return NULL;
}
/* start handling */
event_add(cld->sock_in_watcher, NULL);
return cld;
}
static void scgi_cgi_child_free(scgi_cgi_child *cld) {
/* shared fd */
if (NULL != cld->sock_in_watcher) {
MY_EVENT_FREE(cld->sock_out_watcher);
MY_EVENT_FREE_WITH_FD(cld->sock_in_watcher);
} else {
MY_EVENT_FREE_WITH_FD(cld->sock_out_watcher);
}
MY_EVENT_FREE_WITH_FD(cld->pipe_in_watcher);
MY_EVENT_FREE_WITH_FD(cld->pipe_out_watcher);
if (-1 != cld->child_stdin) {
close(cld->child_stdin);
cld->child_stdin = -1;
}
if (-1 != cld->child_stdout) {
close(cld->child_stdout);
cld->child_stdout = -1;
}
scgi_parser_clear(&cld->req_parser);
if (-1 != cld->pid) {
kill(cld->pid, SIGTERM);
cld->pid = -1;
}
free(cld);
}
static void scgi_cgi_child_check_done(scgi_cgi_child *cld) {
if (-1 == cld->pid && NULL == cld->sock_out_watcher) {
MY_EVENT_FREE_WITH_FD(cld->sock_in_watcher);
MY_EVENT_FREE_WITH_FD(cld->pipe_in_watcher);
MY_EVENT_FREE_WITH_FD(cld->pipe_out_watcher);
}
if (-1 != cld->pid || NULL != cld->sock_out_watcher || NULL != cld->sock_in_watcher || NULL != cld->pipe_in_watcher || NULL != cld->pipe_out_watcher) return;
scgi_cgi_server_child_finished(cld->srv, cld);
}
static const char http_503_message[] =
"Status: 503 Service Unavailable\r\n"
"Content-Length: 0\r\n"
"\r\n"
;
static void scgi_cgi_child_exec(scgi_cgi_child *cld) {
char **newenv;
const char *path = cld->srv->binary;
char * args[] = { NULL, NULL };
if (cld->child_stdin != 0) {
dup2(cld->child_stdin, 0);
close(cld->child_stdin);
}
if (cld->child_stdout != 1) {
dup2(cld->child_stdout, 1);
close(cld->child_stdout);
}
#ifdef FD_CLOEXEC
/* UNDO close fd on exec (cgi) */
fcntl(0, F_SETFD, 0);
fcntl(1, F_SETFD, 0);
#endif
if (NULL == path) path = scgi_parser_environ_get(&cld->req_parser, CONST_STR_LEN("INTERPRETER"));
if (NULL == path) path = scgi_parser_environ_get(&cld->req_parser, CONST_STR_LEN("SCRIPT_FILENAME"));
args[0] = (char*) path;
/* try changing the directory. don't care about memleaks, execve() coming soon :) */
{
char *dir = strdup(path), *sep;
if (NULL == (sep = strrchr(dir, '/'))) {
chdir("/");
} else {
*sep = '\0';
chdir(dir);
}
}
scgi_parser_environ_copy(&cld->req_parser, CONST_STR_LEN("PATH"));
newenv = (char**) cld->req_parser.environ;
execve(path, args, newenv);
fprintf(stderr, "couldn't execve '%s': %s\n", path, strerror(errno));
write(1, http_503_message, sizeof(http_503_message));
exit(-1);
}
static void scgi_cgi_child_start(scgi_cgi_child *cld) {
cld->pid = fork();
switch (cld->pid) {
case 0:
/* child process */
scgi_cgi_child_exec(cld);
break;
case -1:
/* error */
fprintf(stderr, "couldn't fork: %s\n", strerror(errno));
SCGI_BUFFER_SET(&cld->response_buf, http_503_message);
if (NULL != cld->sock_out_watcher) event_add(cld->sock_out_watcher, NULL);
/* don't need those anymore */
scgi_parser_clear_environment(&cld->req_parser);
close(cld->child_stdout); cld->child_stdout = -1;
close(cld->child_stdin); cld->child_stdin = -1;
/* close pipe stuff */
MY_EVENT_FREE_WITH_FD(cld->pipe_in_watcher);
MY_EVENT_FREE_WITH_FD(cld->pipe_out_watcher);
break;
default:
/* don't need those anymore */
scgi_parser_clear_environment(&cld->req_parser);
close(cld->child_stdout); cld->child_stdout = -1;
close(cld->child_stdin); cld->child_stdin = -1;
/* start reading */
event_add(cld->pipe_in_watcher, NULL);
break;
}
}
static void scgi_cgi_close_socket(scgi_cgi_child *cld) {
cld->response_buf.pos = cld->response_buf.len = 0;
/* shared fd */
if (NULL != cld->sock_in_watcher) {
MY_EVENT_FREE(cld->sock_out_watcher);
MY_EVENT_FREE_WITH_FD(cld->sock_in_watcher);
} else {
MY_EVENT_FREE_WITH_FD(cld->sock_out_watcher);
}
if (NULL != cld->pipe_out_watcher) event_add(cld->pipe_out_watcher, NULL);
if (NULL != cld->pipe_in_watcher) event_add(cld->pipe_in_watcher, NULL);
scgi_cgi_child_check_done(cld);
}
static void scgi_cgi_child_sock_in_cb(evutil_socket_t fd, short what, void *arg) {
scgi_cgi_child *cld = (scgi_cgi_child*) arg;
UNUSED(what);
assert(NULL != cld->sock_in_watcher);
for (;;) {
unsigned char *buf;
ssize_t r;
scgi_buffer_input_location(&cld->request_buf, &buf, &r);
if (0 == r) { /* buffer is full */
event_del(cld->sock_in_watcher);
break;
}
r = read(fd, buf, r);
if (0 == r) { /* eof */
/* shared fd */
if (NULL == cld->sock_out_watcher) {
MY_EVENT_FREE_WITH_FD(cld->sock_in_watcher);
} else {
MY_EVENT_FREE(cld->sock_in_watcher);
}
break;
} else if (0 > r) {
switch (errno) {
case EINTR:
case EAGAIN:
#if EWOULDBLOCK != EAGAIN
case EWOULDBLOCK:
#endif
break; /* try again later */
default:
goto close_sock;
}
break;
} else {
if (SCGI_REQ_PARSER_HEADER_DONE != cld->req_parser.state) {
ssize_t result;
assert(0 == cld->request_buf.len);
result = scgi_parse(&cld->req_parser, buf, r);
DEBUG("scgi req parse result: %i", (int) result);
if (result >= 0) {
assert(SCGI_REQ_PARSER_HEADER_DONE == cld->req_parser.state);
if (result > 0) {
cld->request_buf.pos = r - result;
cld->request_buf.len = result;
}
scgi_cgi_child_start(cld);
} else if (result < -1) {
goto close_sock;
}
} else if (NULL != cld->pipe_out_watcher) {
scgi_buffer_fill(&cld->request_buf, r);
} else {
goto close_sock;
}
}
}
if (cld->request_buf.len > cld->req_parser.content_length) {
cld->request_buf.len = cld->req_parser.content_length;
goto close_sock;
}
if (NULL == cld->sock_in_watcher || 0 < cld->request_buf.len || 0 == cld->req_parser.content_length) {
if (NULL != cld->pipe_out_watcher) event_add(cld->pipe_out_watcher, NULL);
}
scgi_cgi_child_check_done(cld);
return;
close_sock:
scgi_cgi_close_socket(cld);
}
static void scgi_cgi_child_sock_out_cb(evutil_socket_t fd, short what, void *arg) {
scgi_cgi_child *cld = (scgi_cgi_child*) arg;
UNUSED(what);
assert(NULL != cld->sock_out_watcher);
for (;;) {
unsigned char *buf;
ssize_t r;
scgi_buffer_output_location(&cld->response_buf, &buf, &r);
if (0 == r) { /* buffer empty */
event_del(cld->sock_out_watcher);
break;
}
r = write(fd, buf, r);
if (0 >= r) {
switch (errno) {
case EINTR:
case EAGAIN:
#if EWOULDBLOCK != EAGAIN
case EWOULDBLOCK:
#endif
break; /* try again later */
default:
goto close_sock;
}
break;
}
scgi_buffer_drain(&cld->response_buf, r);
}
if (0 == cld->response_buf.len && NULL == cld->pipe_in_watcher) {
shutdown(fd, SHUT_RDWR);
goto close_sock;
} else if (NULL != cld->pipe_in_watcher && scgi_buffer_is_input_open(&cld->response_buf)) {
event_add(cld->pipe_in_watcher, NULL);
}
scgi_cgi_child_check_done(cld);
return;
close_sock:
scgi_cgi_close_socket(cld);
}
static void scgi_cgi_child_pipe_in_cb(evutil_socket_t fd, short what, void *arg) {
scgi_cgi_child *cld = (scgi_cgi_child*) arg;
UNUSED(what);
assert(NULL != cld->pipe_in_watcher);
for (;;) {
unsigned char *buf;
ssize_t r;
scgi_buffer_input_location(&cld->response_buf, &buf, &r);
if (0 == r) { /* buffer full */
event_del(cld->pipe_in_watcher);
break;
}
r = read(fd, buf, r);
if (0 == r) { /* eof */
MY_EVENT_FREE_WITH_FD(cld->pipe_in_watcher);
break;
} else if (0 > r) {
switch (errno) {
case EINTR:
case EAGAIN:
#if EWOULDBLOCK != EAGAIN
case EWOULDBLOCK:
#endif
break; /* try again later */
default:
MY_EVENT_FREE_WITH_FD(cld->pipe_in_watcher);
break;
}
break;
} else {
if (NULL != cld->sock_out_watcher) {
scgi_buffer_fill(&cld->response_buf, r);
}
}
}
if (NULL == cld->pipe_in_watcher || cld->response_buf.len > 0) {
if (NULL != cld->sock_out_watcher) event_add(cld->sock_out_watcher, NULL);
}
scgi_cgi_child_check_done(cld);
}
static void scgi_cgi_child_pipe_out_cb(evutil_socket_t fd, short what, void *arg) {
scgi_cgi_child *cld = (scgi_cgi_child*) arg;
UNUSED(what);
assert(NULL != cld->pipe_out_watcher);
for (;;) {
unsigned char *buf;
ssize_t r;
scgi_buffer_output_location(&cld->request_buf, &buf, &r);
assert(cld->req_parser.content_length >= (size_t) r);
if (0 == r) { /* buffer empty */
event_del(cld->pipe_out_watcher);
break;
}
r = write(fd, buf, r);
if (0 >= r) {
switch (errno) {
case EINTR:
case EAGAIN:
#if EWOULDBLOCK != EAGAIN
case EWOULDBLOCK:
#endif
break; /* try again later */
default:
goto close_pipe;
}
break;
}
cld->req_parser.content_length -= r;
scgi_buffer_drain(&cld->request_buf, r);
}
if (0 == cld->req_parser.content_length || (0 == cld->request_buf.len && NULL == cld->sock_in_watcher)) {
goto close_pipe;
} else if (NULL != cld->sock_in_watcher && scgi_buffer_is_input_open(&cld->request_buf)) {
event_add(cld->sock_in_watcher, NULL);
}
scgi_cgi_child_check_done(cld);
return;
close_pipe:
MY_EVENT_FREE_WITH_FD(cld->pipe_out_watcher);
cld->request_buf.pos = cld->request_buf.len = 0;
if (NULL != cld->sock_in_watcher) event_add(cld->sock_in_watcher, NULL);
scgi_cgi_child_check_done(cld);
}
/****************************************************************************
* SCGI SERVER implementation *
***************************************************************************/
#define CATCH_SIGNAL(cb, n) do { \
srv->sig_w_##n = event_new(srv->base, SIG##n, EV_SIGNAL|EV_PERSIST, cb, srv); \
assert(NULL != srv->sig_w_##n); \
event_add(srv->sig_w_##n, NULL); \
} while (0)
#define UNCATCH_SIGNAL(n) MY_EVENT_FREE(srv->sig_w_##n)
static scgi_cgi_server* scgi_cgi_server_create(int fd, const char *binary, unsigned int maxconns) {
scgi_cgi_server* srv = calloc(1, sizeof(scgi_cgi_server));
srv->children = (scgi_cgi_child**) calloc(maxconns, sizeof(scgi_cgi_child*));
assert(NULL != srv->children);
srv->children_used = 0;
srv->children_size = maxconns;
srv->binary = binary;
srv->base = event_base_new();
fd_init(fd);
srv->listen_watcher = event_new(srv->base, fd, EV_READ | EV_PERSIST, scgi_cgi_server_accept, srv);
event_add(srv->listen_watcher, NULL);
CATCH_SIGNAL(sigint_cb, INT);
CATCH_SIGNAL(sigint_cb, TERM);
CATCH_SIGNAL(sigint_cb, HUP);
CATCH_SIGNAL(sigchld_cb, CHLD);
return srv;
}
static void scgi_cgi_server_free(scgi_cgi_server* srv) {
while (srv->children_used > 0) {
scgi_cgi_server_child_finished(srv, srv->children[0]);
}
MY_EVENT_FREE_WITH_FD(srv->listen_watcher);
UNCATCH_SIGNAL(INT);
UNCATCH_SIGNAL(TERM);
UNCATCH_SIGNAL(HUP);
UNCATCH_SIGNAL(CHLD);
free(srv->children);
srv->children = NULL;
srv->children_size = 0;
free(srv);
}
static void scgi_cgi_server_child_finished(scgi_cgi_server *srv, scgi_cgi_child *cld) {
unsigned int ndx = cld->ndx;
assert(srv->children[ndx] == cld);
assert(ndx < srv->children_used);
DEBUG("Child %i finished", ndx);
--srv->children_used;
if (ndx != srv->children_used) {
srv->children[ndx] = srv->children[srv->children_used];
srv->children[ndx]->ndx = ndx;
}
srv->children[srv->children_used] = NULL;
scgi_cgi_child_free(cld);
if (NULL == srv->listen_watcher && 0 == srv->children_used) UNCATCH_SIGNAL(CHLD); /* shutdown */
if (NULL != srv->listen_watcher) event_add(srv->listen_watcher, NULL);
}
static void scgi_cgi_server_accept(evutil_socket_t fd, short what, void *arg) {
scgi_cgi_server *srv = (scgi_cgi_server*) arg;
int confd;
UNUSED(what);
if (srv->children_used == srv->children_size) {
event_del(srv->listen_watcher);
return;
}
while (srv->children_used < srv->children_size) {
if (-1 != (confd = accept(fd, NULL, NULL))) {
scgi_cgi_child *cld;
fd_init(confd);
cld = scgi_cgi_child_create(srv, confd);
if (NULL == cld) {
if (0 == srv->children_used) {
ERROR("no children running, and child creation failed. abort.");
exit(-2);
}
ERROR("child creation failed, disable listening temporarily until next child finishes");
close(confd);
event_del(srv->listen_watcher);
return;
}
srv->children[srv->children_used++] = cld;
} else {
break;
}
}
}
static void sigint_cb(evutil_socket_t fd, short what, void *arg) {
scgi_cgi_server *srv = (scgi_cgi_server*) arg;
UNUSED(fd);
UNUSED(what);
UNCATCH_SIGNAL(INT);
UNCATCH_SIGNAL(TERM);
UNCATCH_SIGNAL(HUP);
MY_EVENT_FREE_WITH_FD(srv->listen_watcher);
if (0 == srv->children_used) UNCATCH_SIGNAL(CHLD);
fprintf(stderr, "Got signal, shutdown (%i children remaining)\n", srv->children_used);
}
static void sigchld_cb(evutil_socket_t fd, short what, void *arg) {
scgi_cgi_server *srv = (scgi_cgi_server*) arg;
pid_t pid;
int status;
UNUSED(fd);
UNUSED(what);
while (srv->children_used > 0) {
if (-1 != (pid = waitpid(-1, &status, WNOHANG))) {
unsigned int i;
for (i = 0; i < srv->children_used; ++i) {
scgi_cgi_child *cld = srv->children[i];
if (cld->pid == pid) {
DEBUG("child %i terminated with status %i", i, status);
cld->pid = -1;
scgi_cgi_child_check_done(cld);
break;
}
}
} else {
break;
}
}
}
static void show_help() {
fprintf(stderr, PACKAGE_DESC "\n");
fprintf(stderr,
"Usage: scgi-cgi [-b binary] [-c maxconns] [-h] [-v] -- [binary]\n"
"Options:\n"
" -b binary the executable to call instead of INTERPRETER\n"
" or SCRIPT_FILENAME from SCGI environment (default: none)\n"
" -c maxconns how many connections to accept at the same time (default: 16)\n"
" -v show version\n"
" -h show this help\n"
);
}
int main (int argc, char **argv) {
scgi_cgi_server *srv;
const char *binary = NULL;
unsigned int maxconn = 16;
int o;
while(-1 != (o = getopt(argc, argv, "b:c:hv"))) {
switch(o) {
case 'b':
binary = optarg;
break;
case 'c':
maxconn = atoi(optarg);
break;
case 'v':
fprintf(stderr, PACKAGE_DESC "\n");
return 0;
case 'h':
show_help();
return 0;
default:
show_help();
return -1;
}
}
if (optind < argc && argv[optind] && NULL == binary) binary = argv[optind];
srv = scgi_cgi_server_create(0, binary, maxconn);
event_base_loop(srv->base, 0);
scgi_cgi_server_free(srv);
return 0;
}
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