src/common/compat/socket.h

   1 /*
   2  * Copyright (C) 2011 - David Goulet <dgoulet@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #ifndef _COMPAT_SOCKET_H
  19 #define _COMPAT_SOCKET_H
  20
  21 #include <sys/socket.h>
  22 #include <sys/un.h>
  23
  24 #include <common/macros.h>
  25
  26 #ifndef MSG_NOSIGNAL
  27 # ifdef SO_NOSIGPIPE
  28 #   define MSG_NOSIGNAL SO_NOSIGPIPE
  29 # endif
  30 #endif
  31
  32 #if defined(MSG_NOSIGNAL)
  33 static inline
  34 ssize_t lttng_recvmsg_nosigpipe(int sockfd, struct msghdr *msg)
  35 {
  36         return recvmsg(sockfd, msg, MSG_NOSIGNAL);
  37 }
  38 #else
  39
  40 #include <signal.h>
  41 #include <errno.h>
  42
  43 static inline
  44 ssize_t lttng_recvmsg_nosigpipe(int sockfd, struct msghdr *msg)
  45 {
  46         ssize_t received;
  47         int saved_err;
  48         sigset_t sigpipe_set, pending_set, old_set;
  49         int sigpipe_was_pending;
  50
  51         /*
  52          * Discard the SIGPIPE from send(), not disturbing any SIGPIPE
  53          * that might be already pending. If a bogus SIGPIPE is sent to
  54          * the entire process concurrently by a malicious user, it may
  55          * be simply discarded.
  56          */
  57         if (sigemptyset(&pending_set)) {
  58                 return -1;
  59         }
  60         /*
  61          * sigpending returns the mask of signals that are _both_
  62          * blocked for the thread _and_ pending for either the thread or
  63          * the entire process.
  64          */
  65         if (sigpending(&pending_set)) {
  66                 return -1;
  67         }
  68         sigpipe_was_pending = sigismember(&pending_set, SIGPIPE);
  69         /*
  70          * If sigpipe was pending, it means it was already blocked, so
  71          * no need to block it.
  72          */
  73         if (!sigpipe_was_pending) {
  74                 if (sigemptyset(&sigpipe_set)) {
  75                         return -1;
  76                 }
  77                 if (sigaddset(&sigpipe_set, SIGPIPE)) {
  78                         return -1;
  79                 }
  80                 if (pthread_sigmask(SIG_BLOCK, &sigpipe_set, &old_set)) {
  81                         return -1;
  82                 }
  83         }
  84
  85         /* Send and save errno. */
  86         received = recvmsg(sockfd, msg, 0);
  87         saved_err = errno;
  88
  89         if (received == -1 && errno == EPIPE && !sigpipe_was_pending) {
  90                 struct timespec timeout = { 0, 0 };
  91                 int ret;
  92
  93                 do {
  94                         ret = sigtimedwait(&sigpipe_set, NULL,
  95                                 &timeout);
  96                 } while (ret == -1 && errno == EINTR);
  97         }
  98         if (!sigpipe_was_pending) {
  99                 if (pthread_sigmask(SIG_SETMASK, &old_set, NULL)) {
 100                         return -1;
 101                 }
 102         }
 103         /* Restore send() errno */
 104         errno = saved_err;
 105
 106         return received;
 107 }
 108 #endif
 109
 110
 111 #ifdef __linux__
 112
 113 #define LTTNG_SOCK_CREDS SCM_CREDENTIALS
 114
 115 typedef struct ucred lttng_sock_cred;
 116
 117 #define LTTNG_SOCK_SET_UID_CRED(c, u) LTTNG_REF(c)->uid = u
 118 #define LTTNG_SOCK_SET_GID_CRED(c, g) LTTNG_REF(c)->gid = g
 119 #define LTTNG_SOCK_SET_PID_CRED(c, p) LTTNG_REF(c)->pid = p
 120
 121 #define LTTNG_SOCK_GET_UID_CRED(c) LTTNG_REF(c)->uid
 122 #define LTTNG_SOCK_GET_GID_CRED(c) LTTNG_REF(c)->gid
 123 #define LTTNG_SOCK_GET_PID_CRED(c) LTTNG_REF(c)->pid
 124
 125 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__))
 126
 127 struct lttng_sock_cred {
 128         uid_t uid;
 129         gid_t gid;
 130 };
 131
 132 typedef struct lttng_sock_cred lttng_sock_cred;
 133
 134 #define LTTNG_SOCK_GET_UID_CRED(c) LTTNG_REF(c)->uid
 135 #define LTTNG_SOCK_GET_GID_CRED(c) LTTNG_REF(c)->gid
 136 #define LTTNG_SOCK_GET_PID_CRED(c) -1
 137
 138 #else
 139 #error "Please add support for your OS."
 140 #endif /* __linux__ , __FreeBSD__ */
 141
 142
 143 #ifdef __sun__
 144
 145 # ifndef CMSG_ALIGN
 146 #  ifdef _CMSG_DATA_ALIGN
 147 #   define CMSG_ALIGN(len) _CMSG_DATA_ALIGN(len)
 148 #  else
 149     /* aligning to sizeof (long) is assumed to be portable (fd.o#40235) */
 150 #   define CMSG_ALIGN(len) (((len) + sizeof (long) - 1) & ~(sizeof (long) - 1))
 151 #  endif
 152 #  ifndef CMSG_SPACE
 153 #    define CMSG_SPACE(len) (CMSG_ALIGN (sizeof (struct cmsghdr)) + CMSG_ALIGN (len))
 154 #  endif
 155 #  ifndef CMSG_LEN
 156 #    define CMSG_LEN(len) (CMSG_ALIGN (sizeof (struct cmsghdr)) + (len))
 157 #  endif
 158 # endif
 159
 160
 161 #include <ucred.h>
 162
 163 static inline
 164 int getpeereid(int s, uid_t *euid, gid_t *gid)
 165 {
 166         int ret = 0;
 167         ucred_t *ucred = NULL;
 168
 169         ret = getpeerucred(s, &ucred);
 170         if (ret == -1) {
 171                 goto end;
 172         }
 173
 174         ret = ucred_geteuid(ucred);
 175         if (ret == -1) {
 176                 goto free;
 177         }
 178         *euid = ret;
 179
 180         ret = ucred_getrgid(ucred);
 181         if (ret == -1) {
 182                 goto free;
 183         }
 184         *gid = ret;
 185         ret = 0;
 186 free:
 187         ucred_free(ucred);
 188 end:
 189         return ret;
 190 }
 191
 192 #endif /* __sun__ */
 193
 194 #endif /* _COMPAT_SOCKET_H */