src/common/compat/socket.hpp

   1 /*
   2  * Copyright (C) 2011 David Goulet <dgoulet@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #ifndef _COMPAT_SOCKET_H
   9 #define _COMPAT_SOCKET_H
  10
  11 #include <common/macros.hpp>
  12
  13 #include <sys/socket.h>
  14 #include <sys/un.h>
  15 #include <unistd.h>
  16
  17 #ifndef MSG_NOSIGNAL
  18 #ifdef SO_NOSIGPIPE
  19 #define MSG_NOSIGNAL SO_NOSIGPIPE
  20 #endif
  21 #endif
  22
  23 #if defined(MSG_NOSIGNAL)
  24 static inline ssize_t lttng_recvmsg_nosigpipe(int sockfd, struct msghdr *msg)
  25 {
  26         return recvmsg(sockfd, msg, MSG_NOSIGNAL);
  27 }
  28 #else
  29
  30 #include <common/compat/errno.hpp>
  31
  32 #include <signal.h>
  33
  34 static inline ssize_t lttng_recvmsg_nosigpipe(int sockfd, struct msghdr *msg)
  35 {
  36         ssize_t received;
  37         int saved_err;
  38         sigset_t sigpipe_set, pending_set, old_set;
  39         int sigpipe_was_pending;
  40
  41         /*
  42          * Discard the SIGPIPE from send(), not disturbing any SIGPIPE
  43          * that might be already pending. If a bogus SIGPIPE is sent to
  44          * the entire process concurrently by a malicious user, it may
  45          * be simply discarded.
  46          */
  47         if (sigemptyset(&pending_set)) {
  48                 return -1;
  49         }
  50         /*
  51          * sigpending returns the mask of signals that are _both_
  52          * blocked for the thread _and_ pending for either the thread or
  53          * the entire process.
  54          */
  55         if (sigpending(&pending_set)) {
  56                 return -1;
  57         }
  58         sigpipe_was_pending = sigismember(&pending_set, SIGPIPE);
  59         /*
  60          * If sigpipe was pending, it means it was already blocked, so
  61          * no need to block it.
  62          */
  63         if (!sigpipe_was_pending) {
  64                 if (sigemptyset(&sigpipe_set)) {
  65                         return -1;
  66                 }
  67                 if (sigaddset(&sigpipe_set, SIGPIPE)) {
  68                         return -1;
  69                 }
  70                 if (pthread_sigmask(SIG_BLOCK, &sigpipe_set, &old_set)) {
  71                         return -1;
  72                 }
  73         }
  74
  75         /* Send and save errno. */
  76         received = recvmsg(sockfd, msg, 0);
  77         saved_err = errno;
  78
  79         if (received == -1 && errno == EPIPE && !sigpipe_was_pending) {
  80                 struct timespec timeout = { 0, 0 };
  81                 int ret;
  82
  83                 do {
  84                         ret = sigtimedwait(&sigpipe_set, NULL, &timeout);
  85                 } while (ret == -1 && errno == EINTR);
  86         }
  87         if (!sigpipe_was_pending) {
  88                 if (pthread_sigmask(SIG_SETMASK, &old_set, NULL)) {
  89                         return -1;
  90                 }
  91         }
  92         /* Restore send() errno */
  93         errno = saved_err;
  94
  95         return received;
  96 }
  97 #endif
  98
  99 #ifdef __sun__
 100
 101 #ifndef CMSG_ALIGN
 102 #ifdef _CMSG_DATA_ALIGN
 103 #define CMSG_ALIGN(len) _CMSG_DATA_ALIGN(len)
 104 #else
 105 /* aligning to sizeof (long) is assumed to be portable (fd.o#40235) */
 106 #define CMSG_ALIGN(len) (((len) + sizeof(long) - 1) & ~(sizeof(long) - 1))
 107 #endif
 108 #ifndef CMSG_SPACE
 109 #define CMSG_SPACE(len) (CMSG_ALIGN(sizeof(struct cmsghdr)) + CMSG_ALIGN(len))
 110 #endif
 111 #ifndef CMSG_LEN
 112 #define CMSG_LEN(len) (CMSG_ALIGN(sizeof(struct cmsghdr)) + (len))
 113 #endif
 114 #endif
 115
 116 #include <ucred.h>
 117
 118 static inline int getpeereid(int s, uid_t *euid, gid_t *gid)
 119 {
 120         int ret = 0;
 121         ucred_t *ucred = NULL;
 122
 123         ret = getpeerucred(s, &ucred);
 124         if (ret == -1) {
 125                 goto end;
 126         }
 127
 128         ret = ucred_geteuid(ucred);
 129         if (ret == -1) {
 130                 goto free;
 131         }
 132         *euid = ret;
 133
 134         ret = ucred_getrgid(ucred);
 135         if (ret == -1) {
 136                 goto free;
 137         }
 138         *gid = ret;
 139
 140         ret = 0;
 141 free:
 142         ucred_free(ucred);
 143 end:
 144         return ret;
 145 }
 146 #endif /* __sun__ */
 147
 148 #if defined(__linux__) || defined(__CYGWIN__)
 149
 150 #define LTTNG_SOCK_CREDS SCM_CREDENTIALS
 151
 152 using lttng_sock_cred = struct ucred;
 153
 154 #define LTTNG_SOCK_SET_UID_CRED(c, u) LTTNG_REF(c)->uid = u
 155 #define LTTNG_SOCK_SET_GID_CRED(c, g) LTTNG_REF(c)->gid = g
 156 #define LTTNG_SOCK_SET_PID_CRED(c, p) LTTNG_REF(c)->pid = p
 157
 158 #define LTTNG_SOCK_GET_UID_CRED(c) LTTNG_REF(c)->uid
 159 #define LTTNG_SOCK_GET_GID_CRED(c) LTTNG_REF(c)->gid
 160 #define LTTNG_SOCK_GET_PID_CRED(c) LTTNG_REF(c)->pid
 161
 162 #elif (defined(__FreeBSD__) || defined(__sun__) || defined(__APPLE__))
 163
 164 struct lttng_sock_cred {
 165         uid_t uid;
 166         gid_t gid;
 167         pid_t pid;
 168 };
 169
 170 typedef struct lttng_sock_cred lttng_sock_cred;
 171
 172 #define LTTNG_SOCK_SET_UID_CRED(c, u) LTTNG_REF(c)->uid = u
 173 #define LTTNG_SOCK_SET_GID_CRED(c, g) LTTNG_REF(c)->gid = g
 174 #define LTTNG_SOCK_SET_PID_CRED(c, p) LTTNG_REF(c)->pid = p
 175
 176 #define LTTNG_SOCK_GET_UID_CRED(c) LTTNG_REF(c)->uid
 177 #define LTTNG_SOCK_GET_GID_CRED(c) LTTNG_REF(c)->gid
 178 #define LTTNG_SOCK_GET_PID_CRED(c) LTTNG_REF(c)->pid
 179
 180 #ifdef __APPLE__
 181
 182 static inline int lttng_get_unix_socket_peer_pid(int socket_fd, pid_t *pid)
 183 {
 184         socklen_t pid_len = (socklen_t) sizeof(*pid);
 185
 186         /* The getsockopt LOCAL_PEERPID option is available since macOS 10.8. */
 187         return getsockopt(socket_fd, SOL_LOCAL, LOCAL_PEERPID, pid, &pid_len);
 188 }
 189
 190 #elif defined(__sun__)
 191
 192 /* Use the getpeerucreds interface on Solaris. */
 193 static inline int lttng_get_unix_socket_peer_pid(int socket_fd, pid_t *pid)
 194 {
 195         int ret = 0;
 196         ucred_t *ucred = NULL;
 197
 198         ret = getpeerucred(s, &ucred);
 199         if (ret == -1) {
 200                 goto end;
 201         }
 202
 203         ret = ucred_getpid(ucred);
 204         if (ret == -1) {
 205                 goto free;
 206         }
 207
 208         *pid = ret;
 209         ret = 0;
 210 free:
 211         ucred_free(ucred);
 212 end:
 213         return ret;
 214 }
 215
 216 #elif defined(__FreeBSD__)
 217
 218 #include <sys/ucred.h>
 219
 220 static inline int lttng_get_unix_socket_peer_pid(int socket_fd, pid_t *pid)
 221 {
 222         int ret;
 223         struct xucred sock_creds = {};
 224         socklen_t sock_creds_len = (socklen_t) sizeof(sock_creds);
 225
 226         /* Only available in FreeBSD 13.0 and up. */
 227         ret = getsockopt(socket_fd, SOL_LOCAL, LOCAL_PEERCRED, &sock_creds, &sock_creds_len);
 228         if (ret) {
 229                 goto end;
 230         }
 231
 232         *pid = sock_creds.cr_pid;
 233 end:
 234         return ret;
 235 }
 236
 237 #endif /* __APPLE__ */
 238
 239 static inline int lttng_get_unix_socket_peer_creds(int socket_fd, struct lttng_sock_cred *creds)
 240 {
 241         int ret;
 242
 243         /* This is a BSD extension that is supported by Cygwin. */
 244         ret = getpeereid(socket_fd, &creds->uid, &creds->gid);
 245         if (ret) {
 246                 goto end;
 247         }
 248
 249         /*
 250          * Getting a peer's PID is a bit more troublesome as it is platform
 251          * specific.
 252          */
 253         ret = lttng_get_unix_socket_peer_pid(socket_fd, &creds->pid);
 254 end:
 255         return ret;
 256 }
 257
 258 #else
 259 #error "Please add support for your OS."
 260 #endif /* __linux__ , __FreeBSD__, __APPLE__ */
 261
 262 #endif /* _COMPAT_SOCKET_H */