X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fsocket-util.c;h=82a33c2077c9da0565e07fc4b1358f786af49d34;hb=e0edde6fee279cdbbf3c179f5f50adaf0c7c7f1e;hp=8d291edb4c2e56e42a6e99a2aa6898379fb92e5e;hpb=e61c056cb94aeffc86cb314ea32726be9b666724;p=sliver-openvswitch.git diff --git a/lib/socket-util.c b/lib/socket-util.c index 8d291edb4..82a33c207 100644 --- a/lib/socket-util.c +++ b/lib/socket-util.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010 Nicira Networks. + * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -17,8 +17,10 @@ #include #include "socket-util.h" #include +#include #include #include +#include #include #include #include @@ -30,9 +32,18 @@ #include #include #include +#include "dynamic-string.h" #include "fatal-signal.h" +#include "packets.h" #include "util.h" #include "vlog.h" +#if AF_PACKET && __linux__ +#include +#endif +#ifdef HAVE_NETLINK +#include "netlink-protocol.h" +#include "netlink-socket.h" +#endif VLOG_DEFINE_THIS_MODULE(socket_util); @@ -45,6 +56,13 @@ VLOG_DEFINE_THIS_MODULE(socket_util); #define LINUX 0 #endif +#ifndef O_DIRECTORY +#define O_DIRECTORY 0 +#endif + +static int getsockopt_int(int fd, int level, int option, const char *optname, + int *valuep); + /* Sets 'fd' to non-blocking mode. Returns 0 if successful, otherwise a * positive errno value. */ int @@ -64,6 +82,21 @@ set_nonblocking(int fd) } } +static int +set_dscp(int fd, uint8_t dscp) +{ + if (dscp > 63) { + return EINVAL; + } + + dscp = dscp << 2; + if (setsockopt(fd, IPPROTO_IP, IP_TOS, &dscp, sizeof dscp)) { + return errno; + } + + return 0; +} + static bool rlim_is_finite(rlim_t limit) { @@ -110,24 +143,67 @@ int lookup_ip(const char *host_name, struct in_addr *addr) { if (!inet_aton(host_name, addr)) { - struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5); + static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5); VLOG_ERR_RL(&rl, "\"%s\" is not a valid IP address", host_name); return ENOENT; } return 0; } +/* Translates 'host_name', which must be a string representation of an IPv6 + * address, into a numeric IPv6 address in '*addr'. Returns 0 if successful, + * otherwise a positive errno value. */ +int +lookup_ipv6(const char *host_name, struct in6_addr *addr) +{ + if (inet_pton(AF_INET6, host_name, addr) != 1) { + static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5); + VLOG_ERR_RL(&rl, "\"%s\" is not a valid IPv6 address", host_name); + return ENOENT; + } + return 0; +} + +/* Translates 'host_name', which must be a host name or a string representation + * of an IP address, into a numeric IP address in '*addr'. Returns 0 if + * successful, otherwise a positive errno value. + * + * Most Open vSwitch code should not use this because it causes deadlocks: + * gethostbyname() sends out a DNS request but that starts a new flow for which + * OVS must set up a flow, but it can't because it's waiting for a DNS reply. + * The synchronous lookup also delays other activty. (Of course we can solve + * this but it doesn't seem worthwhile quite yet.) */ +int +lookup_hostname(const char *host_name, struct in_addr *addr) +{ + struct hostent *h; + + if (inet_aton(host_name, addr)) { + return 0; + } + + h = gethostbyname(host_name); + if (h) { + *addr = *(struct in_addr *) h->h_addr; + return 0; + } + + return (h_errno == HOST_NOT_FOUND ? ENOENT + : h_errno == TRY_AGAIN ? EAGAIN + : h_errno == NO_RECOVERY ? EIO + : h_errno == NO_ADDRESS ? ENXIO + : EINVAL); +} + /* Returns the error condition associated with socket 'fd' and resets the * socket's error status. */ int get_socket_error(int fd) { int error; - socklen_t len = sizeof(error); - if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0) { - struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10); + + if (getsockopt_int(fd, SOL_SOCKET, SO_ERROR, "SO_ERROR", &error)) { error = errno; - VLOG_ERR_RL(&rl, "getsockopt(SO_ERROR): %s", strerror(error)); } return error; } @@ -162,15 +238,13 @@ check_connection_completion(int fd) int drain_rcvbuf(int fd) { - socklen_t rcvbuf_len; - size_t rcvbuf; + int rcvbuf; - rcvbuf_len = sizeof rcvbuf; - if (getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, &rcvbuf_len) < 0) { - static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10); - VLOG_ERR_RL(&rl, "getsockopt(SO_RCVBUF) failed: %s", strerror(errno)); - return errno; + rcvbuf = get_socket_rcvbuf(fd); + if (rcvbuf < 0) { + return -rcvbuf; } + while (rcvbuf > 0) { /* In Linux, specifying MSG_TRUNC in the flags argument causes the * datagram length to be returned, even if that is longer than the @@ -191,6 +265,18 @@ drain_rcvbuf(int fd) return 0; } +/* Returns the size of socket 'sock''s receive buffer (SO_RCVBUF), or a + * negative errno value if an error occurs. */ +int +get_socket_rcvbuf(int sock) +{ + int rcvbuf; + int error; + + error = getsockopt_int(sock, SOL_SOCKET, SO_RCVBUF, "SO_RCVBUF", &rcvbuf); + return error ? -error : rcvbuf; +} + /* Reads and discards up to 'n' datagrams from 'fd', stopping as soon as no * more data can be immediately read. ('fd' should therefore be in * non-blocking mode.)*/ @@ -212,15 +298,89 @@ drain_fd(int fd, size_t n_packets) /* Stores in '*un' a sockaddr_un that refers to file 'name'. Stores in * '*un_len' the size of the sockaddr_un. */ static void -make_sockaddr_un(const char *name, struct sockaddr_un* un, socklen_t *un_len) +make_sockaddr_un__(const char *name, struct sockaddr_un *un, socklen_t *un_len) { un->sun_family = AF_UNIX; - strncpy(un->sun_path, name, sizeof un->sun_path); - un->sun_path[sizeof un->sun_path - 1] = '\0'; + ovs_strzcpy(un->sun_path, name, sizeof un->sun_path); *un_len = (offsetof(struct sockaddr_un, sun_path) + strlen (un->sun_path) + 1); } +/* Stores in '*un' a sockaddr_un that refers to file 'name'. Stores in + * '*un_len' the size of the sockaddr_un. + * + * Returns 0 on success, otherwise a positive errno value. On success, + * '*dirfdp' is either -1 or a nonnegative file descriptor that the caller + * should close after using '*un' to bind or connect. On failure, '*dirfdp' is + * -1. */ +static int +make_sockaddr_un(const char *name, struct sockaddr_un *un, socklen_t *un_len, + int *dirfdp) +{ + enum { MAX_UN_LEN = sizeof un->sun_path - 1 }; + + *dirfdp = -1; + if (strlen(name) > MAX_UN_LEN) { + static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1); + + if (LINUX) { + /* 'name' is too long to fit in a sockaddr_un, but we have a + * workaround for that on Linux: shorten it by opening a file + * descriptor for the directory part of the name and indirecting + * through /proc/self/fd//. */ + char *dir, *base; + char *short_name; + int dirfd; + + dir = dir_name(name); + base = base_name(name); + + dirfd = open(dir, O_DIRECTORY | O_RDONLY); + if (dirfd < 0) { + free(base); + free(dir); + return errno; + } + + short_name = xasprintf("/proc/self/fd/%d/%s", dirfd, base); + free(dir); + free(base); + + if (strlen(short_name) <= MAX_UN_LEN) { + make_sockaddr_un__(short_name, un, un_len); + free(short_name); + *dirfdp = dirfd; + return 0; + } + free(short_name); + close(dirfd); + + VLOG_WARN_RL(&rl, "Unix socket name %s is longer than maximum " + "%d bytes (even shortened)", name, MAX_UN_LEN); + } else { + /* 'name' is too long and we have no workaround. */ + VLOG_WARN_RL(&rl, "Unix socket name %s is longer than maximum " + "%d bytes", name, MAX_UN_LEN); + } + + return ENAMETOOLONG; + } else { + make_sockaddr_un__(name, un, un_len); + return 0; + } +} + +/* Binds Unix domain socket 'fd' to a file with permissions 0700. */ +static int +bind_unix_socket(int fd, struct sockaddr *sun, socklen_t sun_len) +{ + /* According to _Unix Network Programming_, umask should affect bind(). */ + mode_t old_umask = umask(0077); + int error = bind(fd, sun, sun_len) ? errno : 0; + umask(old_umask); + return error; +} + /* Creates a Unix domain socket in the given 'style' (either SOCK_DGRAM or * SOCK_STREAM) that is bound to '*bind_path' (if 'bind_path' is non-null) and * connected to '*connect_path' (if 'connect_path' is non-null). If 'nonblock' @@ -247,9 +407,11 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED, if (nonblock) { int flags = fcntl(fd, F_GETFL, 0); if (flags == -1) { + error = errno; goto error; } if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) { + error = errno; goto error; } } @@ -257,13 +419,21 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED, if (bind_path) { struct sockaddr_un un; socklen_t un_len; - make_sockaddr_un(bind_path, &un, &un_len); - if (unlink(un.sun_path) && errno != ENOENT) { - VLOG_WARN("unlinking \"%s\": %s\n", un.sun_path, strerror(errno)); + int dirfd; + + if (unlink(bind_path) && errno != ENOENT) { + VLOG_WARN("unlinking \"%s\": %s\n", bind_path, strerror(errno)); } fatal_signal_add_file_to_unlink(bind_path); - if (bind(fd, (struct sockaddr*) &un, un_len) - || fchmod(fd, S_IRWXU)) { + + error = make_sockaddr_un(bind_path, &un, &un_len, &dirfd); + if (!error) { + error = bind_unix_socket(fd, (struct sockaddr *) &un, un_len); + } + if (dirfd >= 0) { + close(dirfd); + } + if (error) { goto error; } } @@ -271,9 +441,18 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED, if (connect_path) { struct sockaddr_un un; socklen_t un_len; - make_sockaddr_un(connect_path, &un, &un_len); - if (connect(fd, (struct sockaddr*) &un, un_len) + int dirfd; + + error = make_sockaddr_un(connect_path, &un, &un_len, &dirfd); + if (!error + && connect(fd, (struct sockaddr*) &un, un_len) && errno != EINPROGRESS) { + error = errno; + } + if (dirfd >= 0) { + close(dirfd); + } + if (error) { goto error; } } @@ -282,6 +461,7 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED, if (passcred) { int enable = 1; if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable))) { + error = errno; goto error; } } @@ -290,9 +470,11 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED, return fd; error: - error = errno == EAGAIN ? EPROTO : errno; + if (error == EAGAIN) { + error = EPROTO; + } if (bind_path) { - fatal_signal_remove_file_to_unlink(bind_path); + fatal_signal_unlink_file_now(bind_path); } close(fd); return -error; @@ -306,10 +488,10 @@ get_unix_name_len(socklen_t sun_len) : 0); } -uint32_t -guess_netmask(uint32_t ip) +ovs_be32 +guess_netmask(ovs_be32 ip_) { - ip = ntohl(ip); + uint32_t ip = ntohl(ip_); return ((ip >> 31) == 0 ? htonl(0xff000000) /* Class A */ : (ip >> 30) == 2 ? htonl(0xffff0000) /* Class B */ : (ip >> 29) == 6 ? htonl(0xffffff00) /* Class C */ @@ -378,10 +560,14 @@ exit: * and stores -1 into '*fdp'. * * If 'sinp' is non-null, then on success the target address is stored into - * '*sinp'. */ + * '*sinp'. + * + * 'dscp' becomes the DSCP bits in the IP headers for the new connection. It + * should be in the range [0, 63] and will automatically be shifted to the + * appropriately place in the IP tos field. */ int inet_open_active(int style, const char *target, uint16_t default_port, - struct sockaddr_in *sinp, int *fdp) + struct sockaddr_in *sinp, int *fdp, uint8_t dscp) { struct sockaddr_in sin; int fd = -1; @@ -402,37 +588,37 @@ inet_open_active(int style, const char *target, uint16_t default_port, } error = set_nonblocking(fd); if (error) { - goto exit_close; + goto exit; + } + + /* The dscp bits must be configured before connect() to ensure that the TOS + * field is set during the connection establishment. If set after + * connect(), the handshake SYN frames will be sent with a TOS of 0. */ + error = set_dscp(fd, dscp); + if (error) { + VLOG_ERR("%s: socket: %s", target, strerror(error)); + goto exit; } /* Connect. */ error = connect(fd, (struct sockaddr *) &sin, sizeof sin) == 0 ? 0 : errno; if (error == EINPROGRESS) { error = EAGAIN; - } else if (error && error != EAGAIN) { - goto exit_close; } - /* Success: error is 0 or EAGAIN. */ - goto exit; - -exit_close: - close(fd); exit: if (!error || error == EAGAIN) { if (sinp) { *sinp = sin; } - *fdp = fd; - } else { - *fdp = -1; + } else if (fd >= 0) { + close(fd); } + *fdp = fd; return error; } -/* Opens a non-blocking IPv4 socket of the specified 'style', binds to - * 'target', and listens for incoming connections. 'target' should be a string - * in the format "[][:]": +/* Parses 'target', which should be a string in the format "[][:]": * * - If 'default_port' is -1, then is required. Otherwise, if * is omitted, then 'default_port' is used instead. @@ -442,106 +628,141 @@ exit: * * - If is omitted then the IP address is wildcarded. * - * 'style' should be SOCK_STREAM (for TCP) or SOCK_DGRAM (for UDP). - * - * For TCP, the socket will have SO_REUSEADDR turned on. - * - * On success, returns a non-negative file descriptor. On failure, returns a - * negative errno value. - * - * If 'sinp' is non-null, then on success the bound address is stored into - * '*sinp'. */ -int -inet_open_passive(int style, const char *target_, int default_port, - struct sockaddr_in *sinp) + * If successful, stores the address into '*sinp' and returns true; otherwise + * zeros '*sinp' and returns false. */ +bool +inet_parse_passive(const char *target_, int default_port, + struct sockaddr_in *sinp) { char *target = xstrdup(target_); char *string_ptr = target; - struct sockaddr_in sin; const char *host_name; const char *port_string; - int fd = 0, error, port; - unsigned int yes = 1; + bool ok = false; + int port; /* Address defaults. */ - memset(&sin, 0, sizeof sin); - sin.sin_family = AF_INET; - sin.sin_addr.s_addr = htonl(INADDR_ANY); - sin.sin_port = htons(default_port); + memset(sinp, 0, sizeof *sinp); + sinp->sin_family = AF_INET; + sinp->sin_addr.s_addr = htonl(INADDR_ANY); + sinp->sin_port = htons(default_port); /* Parse optional port number. */ port_string = strsep(&string_ptr, ":"); if (port_string && str_to_int(port_string, 10, &port)) { - sin.sin_port = htons(port); + sinp->sin_port = htons(port); } else if (default_port < 0) { VLOG_ERR("%s: port number must be specified", target_); - error = EAFNOSUPPORT; goto exit; } /* Parse optional bind IP. */ host_name = strsep(&string_ptr, ":"); - if (host_name && host_name[0]) { - error = lookup_ip(host_name, &sin.sin_addr); - if (error) { - goto exit; - } + if (host_name && host_name[0] && lookup_ip(host_name, &sinp->sin_addr)) { + goto exit; + } + + ok = true; + +exit: + if (!ok) { + memset(sinp, 0, sizeof *sinp); + } + free(target); + return ok; +} + + +/* Opens a non-blocking IPv4 socket of the specified 'style', binds to + * 'target', and listens for incoming connections. Parses 'target' in the same + * way was inet_parse_passive(). + * + * 'style' should be SOCK_STREAM (for TCP) or SOCK_DGRAM (for UDP). + * + * For TCP, the socket will have SO_REUSEADDR turned on. + * + * On success, returns a non-negative file descriptor. On failure, returns a + * negative errno value. + * + * If 'sinp' is non-null, then on success the bound address is stored into + * '*sinp'. + * + * 'dscp' becomes the DSCP bits in the IP headers for the new connection. It + * should be in the range [0, 63] and will automatically be shifted to the + * appropriately place in the IP tos field. */ +int +inet_open_passive(int style, const char *target, int default_port, + struct sockaddr_in *sinp, uint8_t dscp) +{ + struct sockaddr_in sin; + int fd = 0, error; + unsigned int yes = 1; + + if (!inet_parse_passive(target, default_port, &sin)) { + return -EAFNOSUPPORT; } /* Create non-blocking socket, set SO_REUSEADDR. */ fd = socket(AF_INET, style, 0); if (fd < 0) { error = errno; - VLOG_ERR("%s: socket: %s", target_, strerror(error)); - goto exit; + VLOG_ERR("%s: socket: %s", target, strerror(error)); + return -error; } error = set_nonblocking(fd); if (error) { - goto exit_close; + goto error; } if (style == SOCK_STREAM && setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof yes) < 0) { error = errno; - VLOG_ERR("%s: setsockopt(SO_REUSEADDR): %s", target_, strerror(error)); - goto exit_close; + VLOG_ERR("%s: setsockopt(SO_REUSEADDR): %s", target, strerror(error)); + goto error; } /* Bind. */ if (bind(fd, (struct sockaddr *) &sin, sizeof sin) < 0) { error = errno; - VLOG_ERR("%s: bind: %s", target_, strerror(error)); - goto exit_close; + VLOG_ERR("%s: bind: %s", target, strerror(error)); + goto error; + } + + /* The dscp bits must be configured before connect() to ensure that the TOS + * field is set during the connection establishment. If set after + * connect(), the handshake SYN frames will be sent with a TOS of 0. */ + error = set_dscp(fd, dscp); + if (error) { + VLOG_ERR("%s: socket: %s", target, strerror(error)); + goto error; } /* Listen. */ - if (listen(fd, 10) < 0) { + if (style == SOCK_STREAM && listen(fd, 10) < 0) { error = errno; - VLOG_ERR("%s: listen: %s", target_, strerror(error)); - goto exit_close; + VLOG_ERR("%s: listen: %s", target, strerror(error)); + goto error; } if (sinp) { socklen_t sin_len = sizeof sin; if (getsockname(fd, (struct sockaddr *) &sin, &sin_len) < 0){ error = errno; - VLOG_ERR("%s: getsockname: %s", target_, strerror(error)); - goto exit_close; + VLOG_ERR("%s: getsockname: %s", target, strerror(error)); + goto error; } if (sin.sin_family != AF_INET || sin_len != sizeof sin) { - VLOG_ERR("%s: getsockname: invalid socket name", target_); - goto exit_close; + error = EAFNOSUPPORT; + VLOG_ERR("%s: getsockname: invalid socket name", target); + goto error; } *sinp = sin; } - error = 0; - goto exit; + return fd; -exit_close: +error: close(fd); -exit: - free(target); - return error ? -error : fd; + return -error; } /* Returns a readable and writable fd for /dev/null, if successful, otherwise @@ -663,3 +884,170 @@ get_mtime(const char *file_name, struct timespec *mtime) } } +void +xpipe(int fds[2]) +{ + if (pipe(fds)) { + VLOG_FATAL("failed to create pipe (%s)", strerror(errno)); + } +} + +static int +getsockopt_int(int fd, int level, int option, const char *optname, int *valuep) +{ + static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10); + socklen_t len; + int value; + int error; + + len = sizeof value; + if (getsockopt(fd, level, option, &value, &len)) { + error = errno; + VLOG_ERR_RL(&rl, "getsockopt(%s): %s", optname, strerror(error)); + } else if (len != sizeof value) { + error = EINVAL; + VLOG_ERR_RL(&rl, "getsockopt(%s): value is %u bytes (expected %zu)", + optname, (unsigned int) len, sizeof value); + } else { + error = 0; + } + + *valuep = error ? 0 : value; + return error; +} + +static void +describe_sockaddr(struct ds *string, int fd, + int (*getaddr)(int, struct sockaddr *, socklen_t *)) +{ + struct sockaddr_storage ss; + socklen_t len = sizeof ss; + + if (!getaddr(fd, (struct sockaddr *) &ss, &len)) { + if (ss.ss_family == AF_INET) { + struct sockaddr_in sin; + + memcpy(&sin, &ss, sizeof sin); + ds_put_format(string, IP_FMT":%"PRIu16, + IP_ARGS(&sin.sin_addr.s_addr), ntohs(sin.sin_port)); + } else if (ss.ss_family == AF_UNIX) { + struct sockaddr_un sun; + const char *null; + size_t maxlen; + + memcpy(&sun, &ss, sizeof sun); + maxlen = len - offsetof(struct sockaddr_un, sun_path); + null = memchr(sun.sun_path, '\0', maxlen); + ds_put_buffer(string, sun.sun_path, + null ? null - sun.sun_path : maxlen); + } +#ifdef HAVE_NETLINK + else if (ss.ss_family == AF_NETLINK) { + int protocol; + +/* SO_PROTOCOL was introduced in 2.6.32. Support it regardless of the version + * of the Linux kernel headers in use at build time. */ +#ifndef SO_PROTOCOL +#define SO_PROTOCOL 38 +#endif + + if (!getsockopt_int(fd, SOL_SOCKET, SO_PROTOCOL, "SO_PROTOCOL", + &protocol)) { + switch (protocol) { + case NETLINK_ROUTE: + ds_put_cstr(string, "NETLINK_ROUTE"); + break; + + case NETLINK_GENERIC: + ds_put_cstr(string, "NETLINK_GENERIC"); + break; + + default: + ds_put_format(string, "AF_NETLINK family %d", protocol); + break; + } + } else { + ds_put_cstr(string, "AF_NETLINK"); + } + } +#endif +#if AF_PACKET && __linux__ + else if (ss.ss_family == AF_PACKET) { + struct sockaddr_ll sll; + + memcpy(&sll, &ss, sizeof sll); + ds_put_cstr(string, "AF_PACKET"); + if (sll.sll_ifindex) { + char name[IFNAMSIZ]; + + if (if_indextoname(sll.sll_ifindex, name)) { + ds_put_format(string, "(%s)", name); + } else { + ds_put_format(string, "(ifindex=%d)", sll.sll_ifindex); + } + } + if (sll.sll_protocol) { + ds_put_format(string, "(protocol=0x%"PRIu16")", + ntohs(sll.sll_protocol)); + } + } +#endif + else if (ss.ss_family == AF_UNSPEC) { + ds_put_cstr(string, "AF_UNSPEC"); + } else { + ds_put_format(string, "AF_%d", (int) ss.ss_family); + } + } +} + + +#ifdef __linux__ +static void +put_fd_filename(struct ds *string, int fd) +{ + char buf[1024]; + char *linkname; + int n; + + linkname = xasprintf("/proc/self/fd/%d", fd); + n = readlink(linkname, buf, sizeof buf); + if (n > 0) { + ds_put_char(string, ' '); + ds_put_buffer(string, buf, n); + if (n > sizeof buf) { + ds_put_cstr(string, "..."); + } + } + free(linkname); +} +#endif + +/* Returns a malloc()'d string describing 'fd', for use in logging. */ +char * +describe_fd(int fd) +{ + struct ds string; + struct stat s; + + ds_init(&string); + if (fstat(fd, &s)) { + ds_put_format(&string, "fstat failed (%s)", strerror(errno)); + } else if (S_ISSOCK(s.st_mode)) { + describe_sockaddr(&string, fd, getsockname); + ds_put_cstr(&string, "<->"); + describe_sockaddr(&string, fd, getpeername); + } else { + ds_put_cstr(&string, (isatty(fd) ? "tty" + : S_ISDIR(s.st_mode) ? "directory" + : S_ISCHR(s.st_mode) ? "character device" + : S_ISBLK(s.st_mode) ? "block device" + : S_ISREG(s.st_mode) ? "file" + : S_ISFIFO(s.st_mode) ? "FIFO" + : S_ISLNK(s.st_mode) ? "symbolic link" + : "unknown")); +#ifdef __linux__ + put_fd_filename(&string, fd); +#endif + } + return ds_steal_cstr(&string); +}