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