src/ctl.c

   1 /* -*- mode: c; c-file-style: "openbsd" -*- */
   2 /*
   3  * Copyright (c) 2008 Vincent Bernat <bernat@luffy.cx>
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #include <stdlib.h>
  19 #include <unistd.h>
  20 #include <fcntl.h>
  21 #include <errno.h>
  22 #include <sys/types.h>
  23 #include <sys/socket.h>
  24 #include <sys/un.h>
  25 #include <string.h>
  26
  27 #include "ctl.h"
  28 #include "marshal.h"
  29 #include "log.h"
  30 #include "compat/compat.h"
  31
  32 #define UNIX_PATH_MAX   108
  33
  34 /**
  35  * Create a new listening Unix socket for control protocol.
  36  *
  37  * @param name The name of the Unix socket.
  38  * @return The socket when successful, -1 otherwise.
  39  */
  40 int
  41 ctl_create(char *name)
  42 {
  43         int s;
  44         struct sockaddr_un su;
  45         int rc;
  46
  47         log_debug("control", "create control socket %s", name);
  48
  49         if ((s = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
  50                 return -1;
  51         su.sun_family = AF_UNIX;
  52         strlcpy(su.sun_path, name, UNIX_PATH_MAX);
  53         if (bind(s, (struct sockaddr *)&su, sizeof(struct sockaddr_un)) == -1) {
  54                 rc = errno; close(s); errno = rc;
  55                 return -1;
  56         }
  57
  58         log_debug("control", "listen to control socket %s", name);
  59         if (listen(s, 5) == -1) {
  60                 rc = errno; close(s); errno = rc;
  61                 log_debug("control", "cannot listen to control socket %s", name);
  62                 return -1;
  63         }
  64         return s;
  65 }
  66
  67 /**
  68  * Connect to the control Unix socket.
  69  *
  70  * @param name The name of the Unix socket.
  71  * @return The socket when successful, -1 otherwise.
  72  */
  73 int
  74 ctl_connect(char *name)
  75 {
  76         int s;
  77         struct sockaddr_un su;
  78         int rc;
  79
  80         log_debug("control", "connect to control socket %s", name);
  81
  82         if ((s = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
  83                 return -1;
  84         su.sun_family = AF_UNIX;
  85         strlcpy(su.sun_path, name, UNIX_PATH_MAX);
  86         if (connect(s, (struct sockaddr *)&su, sizeof(struct sockaddr_un)) == -1) {
  87                 rc = errno;
  88                 log_warn("control", "unable to connect to socket %s", name);
  89                 errno = rc; return -1;
  90         }
  91         return s;
  92 }
  93
  94 /**
  95  * Remove the control Unix socket.
  96  *
  97  * @param name The name of the Unix socket.
  98  */
  99 void
 100 ctl_cleanup(char *name)
 101 {
 102         log_debug("control", "cleanup control socket");
 103         if (unlink(name) == -1)
 104                 log_warn("control", "unable to unlink %s", name);
 105 }
 106
 107 /**
 108  * Serialize and "send" a structure through the control protocol.
 109  *
 110  * This function does not really send the message but outputs it to a buffer.
 111  *
 112  * @param output_buffer A pointer to a buffer to which the message will be
 113  *                      appended. Can be @c NULL. In this case, the buffer will
 114  *                      be allocated.
 115  * @param[in,out] output_len The length of the provided buffer. Will be updated
 116  *                           with the new length
 117  * @param type  The type of message we want to send.
 118  * @param t     The structure to be serialized and sent.
 119  * @param mi    The appropriate marshal structure for serialization.
 120  * @return -1 in case of failure, 0 in case of success.
 121  *
 122  * Make sure this function logic matches the server-side one: @c levent_ctl_recv().
 123  */
 124 int
 125 ctl_msg_send_unserialized(uint8_t **output_buffer, size_t *output_len,
 126     enum hmsg_type type,
 127     void *t, struct marshal_info *mi)
 128 {
 129         struct hmsg_header hdr;
 130         size_t len = 0, newlen;
 131         void *buffer = NULL;
 132
 133         log_debug("control", "send a message through control socket");
 134         if (t) {
 135                 len = marshal_serialize_(mi, t, &buffer, 0, NULL, 0);
 136                 if (len <= 0) {
 137                         log_warnx("control", "unable to serialize data");
 138                         return -1;
 139                 }
 140         }
 141
 142         newlen = len + sizeof(struct hmsg_header);
 143
 144         if (*output_buffer == NULL) {
 145                 *output_len = 0;
 146                 if ((*output_buffer = malloc(newlen)) == NULL) {
 147                         log_warn("control", "no memory available");
 148                         free(buffer);
 149                         return -1;
 150                 }
 151         } else {
 152                 void *new = realloc(*output_buffer, *output_len + newlen);
 153                 if (new == NULL) {
 154                         log_warn("control", "no memory available");
 155                         free(buffer);
 156                         return -1;
 157                 }
 158                 *output_buffer = new;
 159         }
 160         memset(&hdr, 0, sizeof(struct hmsg_header));
 161         hdr.type = type;
 162         hdr.len  = len;
 163         memcpy(*output_buffer + *output_len, &hdr, sizeof(struct hmsg_header));
 164         if (t)
 165                 memcpy(*output_buffer + *output_len + sizeof(struct hmsg_header), buffer, len);
 166         *output_len += newlen;
 167         free(buffer);
 168         return 0;
 169 }
 170
 171 /**
 172  * "Receive" and unserialize a structure through the control protocol.
 173  *
 174  * Like @c ctl_msg_send_unserialized(), this function uses buffer to receive the
 175  * incoming message.
 176  *
 177  * @param[in,out] input_buffer The buffer with the incoming message. Will be
 178  *                             updated once the message has been unserialized to
 179  *                             point to the remaining of the message or will be
 180  *                             freed if all the buffer has been consumed. Can be
 181  *                             @c NULL.
 182  * @param[in,out] input_len    The length of the provided buffer. Will be updated
 183  *                             to the length of remaining data once the message
 184  *                             has been unserialized.
 185  * @param expected_type        The expected message type.
 186  * @param[out] t               Will contain a pointer to the unserialized structure.
 187  *                             Can be @c NULL if we don't want to store the
 188  *                             answer.
 189  * @param mi                   The appropriate marshal structure for unserialization.
 190  *
 191  * @return -1 in case of error, 0 in case of success and the number of bytes we
 192  *         request to complete unserialization.
 193  *
 194  * When requesting a notification, the input buffer is left untouched if we
 195  * don't get one and we fail silently.
 196  */
 197 size_t
 198 ctl_msg_recv_unserialized(uint8_t **input_buffer, size_t *input_len,
 199     enum hmsg_type expected_type,
 200     void **t, struct marshal_info *mi)
 201 {
 202         struct hmsg_header hdr;
 203         int rc = -1;
 204
 205         if (*input_buffer == NULL ||
 206             *input_len < sizeof(struct hmsg_header)) {
 207                 /* Not enough data. */
 208                 return sizeof(struct hmsg_header) - *input_len;
 209         }
 210
 211         log_debug("control", "receive a message through control socket");
 212         memcpy(&hdr, *input_buffer, sizeof(struct hmsg_header));
 213         if (hdr.len > HMSG_MAX_SIZE) {
 214                 log_warnx("control", "message received is too large");
 215                 /* We discard the whole buffer */
 216                 free(*input_buffer);
 217                 *input_buffer = NULL;
 218                 *input_len = 0;
 219                 return -1;
 220         }
 221         if (*input_len < sizeof(struct hmsg_header) + hdr.len) {
 222                 /* Not enough data. */
 223                 return sizeof(struct hmsg_header) + hdr.len - *input_len;
 224         }
 225         if (hdr.type != expected_type) {
 226                 if (expected_type == NOTIFICATION) return -1;
 227                 log_warnx("control", "incorrect received message type (expected: %d, received: %d)",
 228                     expected_type, hdr.type);
 229                 goto end;
 230         }
 231
 232         if (t && !hdr.len) {
 233                 log_warnx("control", "no payload available in answer");
 234                 goto end;
 235         }
 236         if (t) {
 237                 /* We have data to unserialize. */
 238                 if (marshal_unserialize_(mi, *input_buffer + sizeof(struct hmsg_header),
 239                         hdr.len, t, NULL, 0, 0) <= 0) {
 240                         log_warnx("control", "unable to deserialize received data");
 241                         goto end;
 242                 }
 243         }
 244
 245         rc = 0;
 246 end:
 247         /* Discard input buffer */
 248         *input_len -= sizeof(struct hmsg_header) + hdr.len;
 249         if (*input_len == 0) {
 250                 free(*input_buffer);
 251                 *input_buffer = NULL;
 252         } else
 253                 memmove(*input_buffer,
 254                     *input_buffer + sizeof(struct hmsg_header) + hdr.len,
 255                     *input_len);
 256         return rc;
 257 }