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 /**
  33  * Create a new listening Unix socket for control protocol.
  34  *
  35  * @param name The name of the Unix socket.
  36  * @return The socket when successful, -1 otherwise.
  37  */
  38 int
  39 ctl_create(char *name)
  40 {
  41         int s;
  42         struct sockaddr_un su;
  43         int rc;
  44
  45         log_debug("control", "create control socket %s", name);
  46
  47         if ((s = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
  48                 return -1;
  49         su.sun_family = AF_UNIX;
  50         strlcpy(su.sun_path, name, sizeof(su.sun_path));
  51         if (bind(s, (struct sockaddr *)&su, sizeof(struct sockaddr_un)) == -1) {
  52                 rc = errno; close(s); errno = rc;
  53                 return -1;
  54         }
  55
  56         log_debug("control", "listen to control socket %s", name);
  57         if (listen(s, 5) == -1) {
  58                 rc = errno; close(s); errno = rc;
  59                 log_debug("control", "cannot listen to control socket %s", name);
  60                 return -1;
  61         }
  62         return s;
  63 }
  64
  65 /**
  66  * Connect to the control Unix socket.
  67  *
  68  * @param name The name of the Unix socket.
  69  * @return The socket when successful, -1 otherwise.
  70  */
  71 int
  72 ctl_connect(char *name)
  73 {
  74         int s;
  75         struct sockaddr_un su;
  76         int rc;
  77
  78         log_debug("control", "connect to control socket %s", name);
  79
  80         if ((s = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
  81                 return -1;
  82         su.sun_family = AF_UNIX;
  83         strlcpy(su.sun_path, name, sizeof(su.sun_path));
  84         if (connect(s, (struct sockaddr *)&su, sizeof(struct sockaddr_un)) == -1) {
  85                 rc = errno;
  86                 log_warn("control", "unable to connect to socket %s", name);
  87                 close(s);
  88                 errno = rc; return -1;
  89         }
  90         return s;
  91 }
  92
  93 /**
  94  * Remove the control Unix socket.
  95  *
  96  * @param name The name of the Unix socket.
  97  */
  98 void
  99 ctl_cleanup(char *name)
 100 {
 101         log_debug("control", "cleanup control socket");
 102         if (unlink(name) == -1)
 103                 log_warn("control", "unable to unlink %s", name);
 104 }
 105
 106 /**
 107  * Serialize and "send" a structure through the control protocol.
 108  *
 109  * This function does not really send the message but outputs it to a buffer.
 110  *
 111  * @param output_buffer A pointer to a buffer to which the message will be
 112  *                      appended. Can be @c NULL. In this case, the buffer will
 113  *                      be allocated.
 114  * @param[in,out] output_len The length of the provided buffer. Will be updated
 115  *                           with the new length
 116  * @param type  The type of message we want to send.
 117  * @param t     The structure to be serialized and sent.
 118  * @param mi    The appropriate marshal structure for serialization.
 119  * @return -1 in case of failure, 0 in case of success.
 120  *
 121  * Make sure this function logic matches the server-side one: @c levent_ctl_recv().
 122  */
 123 int
 124 ctl_msg_send_unserialized(uint8_t **output_buffer, size_t *output_len,
 125     enum hmsg_type type,
 126     void *t, struct marshal_info *mi)
 127 {
 128         struct hmsg_header hdr;
 129         ssize_t len = 0, newlen;
 130         void *buffer = NULL;
 131
 132         log_debug("control", "send a message through control socket");
 133         if (t) {
 134                 len = marshal_serialize_(mi, t, &buffer, 0, NULL, 0);
 135                 if (len <= 0) {
 136                         log_warnx("control", "unable to serialize data");
 137                         return -1;
 138                 }
 139         }
 140
 141         newlen = len + sizeof(struct hmsg_header);
 142
 143         if (*output_buffer == NULL) {
 144                 *output_len = 0;
 145                 if ((*output_buffer = malloc(newlen)) == NULL) {
 146                         log_warn("control", "no memory available");
 147                         free(buffer);
 148                         return -1;
 149                 }
 150         } else {
 151                 void *new = realloc(*output_buffer, *output_len + newlen);
 152                 if (new == NULL) {
 153                         log_warn("control", "no memory available");
 154                         free(buffer);
 155                         return -1;
 156                 }
 157                 *output_buffer = new;
 158         }
 159         memset(&hdr, 0, sizeof(struct hmsg_header));
 160         hdr.type = type;
 161         hdr.len  = len;
 162         memcpy(*output_buffer + *output_len, &hdr, sizeof(struct hmsg_header));
 163         if (t)
 164                 memcpy(*output_buffer + *output_len + sizeof(struct hmsg_header), buffer, len);
 165         *output_len += newlen;
 166         free(buffer);
 167         return 0;
 168 }
 169
 170 /**
 171  * "Receive" and unserialize a structure through the control protocol.
 172  *
 173  * Like @c ctl_msg_send_unserialized(), this function uses buffer to receive the
 174  * incoming message.
 175  *
 176  * @param[in,out] input_buffer The buffer with the incoming message. Will be
 177  *                             updated once the message has been unserialized to
 178  *                             point to the remaining of the message or will be
 179  *                             freed if all the buffer has been consumed. Can be
 180  *                             @c NULL.
 181  * @param[in,out] input_len    The length of the provided buffer. Will be updated
 182  *                             to the length of remaining data once the message
 183  *                             has been unserialized.
 184  * @param expected_type        The expected message type.
 185  * @param[out] t               Will contain a pointer to the unserialized structure.
 186  *                             Can be @c NULL if we don't want to store the
 187  *                             answer.
 188  * @param mi                   The appropriate marshal structure for unserialization.
 189  *
 190  * @return -1 in case of error, 0 in case of success and the number of bytes we
 191  *         request to complete unserialization.
 192  *
 193  * When requesting a notification, the input buffer is left untouched if we
 194  * don't get one and we fail silently.
 195  */
 196 size_t
 197 ctl_msg_recv_unserialized(uint8_t **input_buffer, size_t *input_len,
 198     enum hmsg_type expected_type,
 199     void **t, struct marshal_info *mi)
 200 {
 201         struct hmsg_header hdr;
 202         int rc = -1;
 203
 204         if (*input_buffer == NULL ||
 205             *input_len < sizeof(struct hmsg_header)) {
 206                 /* Not enough data. */
 207                 return sizeof(struct hmsg_header) - *input_len;
 208         }
 209
 210         log_debug("control", "receive a message through control socket");
 211         memcpy(&hdr, *input_buffer, sizeof(struct hmsg_header));
 212         if (hdr.len > HMSG_MAX_SIZE) {
 213                 log_warnx("control", "message received is too large");
 214                 /* We discard the whole buffer */
 215                 free(*input_buffer);
 216                 *input_buffer = NULL;
 217                 *input_len = 0;
 218                 return -1;
 219         }
 220         if (*input_len < sizeof(struct hmsg_header) + hdr.len) {
 221                 /* Not enough data. */
 222                 return sizeof(struct hmsg_header) + hdr.len - *input_len;
 223         }
 224         if (hdr.type != expected_type) {
 225                 if (expected_type == NOTIFICATION) return -1;
 226                 log_warnx("control", "incorrect received message type (expected: %d, received: %d)",
 227                     expected_type, hdr.type);
 228                 goto end;
 229         }
 230
 231         if (t && !hdr.len) {
 232                 log_warnx("control", "no payload available in answer");
 233                 goto end;
 234         }
 235         if (t) {
 236                 /* We have data to unserialize. */
 237                 if (marshal_unserialize_(mi, *input_buffer + sizeof(struct hmsg_header),
 238                         hdr.len, t, NULL, 0, 0) <= 0) {
 239                         log_warnx("control", "unable to deserialize received data");
 240                         goto end;
 241                 }
 242         }
 243
 244         rc = 0;
 245 end:
 246         /* Discard input buffer */
 247         *input_len -= sizeof(struct hmsg_header) + hdr.len;
 248         if (*input_len == 0) {
 249                 free(*input_buffer);
 250                 *input_buffer = NULL;
 251         } else
 252                 memmove(*input_buffer,
 253                     *input_buffer + sizeof(struct hmsg_header) + hdr.len,
 254                     *input_len);
 255         return rc;
 256 }