From 2dae156b134735a52d29f544e4c9e12d03baa283 Mon Sep 17 00:00:00 2001 From: Pierre-Marc Fournier Date: Wed, 10 Feb 2010 17:15:50 -0500 Subject: [PATCH] refactor/enhance libustcomm - regroup sending and receiving code - add \0 at end of messages - add dynamic allocation of received message buffers - remove message length limit --- include/share.h | 32 ++++++++++++++- libustcomm/ustcomm.c | 97 +++++++++++++++++++++++++++++++------------- 2 files changed, 100 insertions(+), 29 deletions(-) diff --git a/include/share.h b/include/share.h index f674f31..1f2195e 100644 --- a/include/share.h +++ b/include/share.h @@ -1,13 +1,19 @@ #ifndef UST_SHARE_H #define UST_SHARE_H +/* write() */ #include + +/* send() */ +#include +#include + #include /* This write is patient because it restarts if it was incomplete. */ -static inline ssize_t patient_write(int fd, const void *buf, size_t count) +static __inline__ ssize_t patient_write(int fd, const void *buf, size_t count) { const char *bufc = (const char *) buf; int result; @@ -31,4 +37,28 @@ static inline ssize_t patient_write(int fd, const void *buf, size_t count) return bufc-(const char *)buf; } +static __inline__ ssize_t patient_send(int fd, const void *buf, size_t count, int flags) +{ + const char *bufc = (const char *) buf; + int result; + + for(;;) { + result = send(fd, bufc, count, flags); + if(result == -1 && errno == EINTR) { + continue; + } + if(result <= 0) { + return result; + } + count -= result; + bufc += result; + + if(count == 0) { + break; + } + } + + return bufc-(const char *)buf; +} + #endif /* UST_SHARE_H */ diff --git a/libustcomm/ustcomm.c b/libustcomm/ustcomm.c index 4d6a650..e1a2d5b 100644 --- a/libustcomm/ustcomm.c +++ b/libustcomm/ustcomm.c @@ -32,6 +32,7 @@ #include "ustcomm.h" #include "usterr.h" +#include "share.h" #define UNIX_PATH_MAX 108 @@ -74,19 +75,33 @@ int pid_is_online(pid_t pid) { return 1; } +/* Send a message + * + * @fd: file descriptor to send to + * @msg: a null-terminated string containing the message to send + * + * Return value: + * -1: error + * 0: connection closed + * 1: success + */ + static int send_message_fd(int fd, const char *msg) { int result; - result = send(fd, msg, strlen(msg), MSG_NOSIGNAL); + /* Send including the final \0 */ + result = patient_send(fd, msg, strlen(msg)+1, MSG_NOSIGNAL); if(result == -1) { - PERROR("send"); + if(errno != EPIPE) + PERROR("send"); return -1; } else if(result == 0) { return 0; } + DBG("sent message \"%s\"", msg); return 1; } @@ -146,26 +161,56 @@ int ustcomm_request_consumer(pid_t pid, const char *channel) * returns -1 to indicate an error */ -static int recv_message_fd(int fd, char **msg, struct ustcomm_source *src) +#define RECV_INCREMENT 1 + +static int recv_message_fd(int fd, char **msg) { int result; + int buf_alloc_size = 0; + char *buf = NULL; + int buf_used_size = 0; - *msg = (char *) malloc(MSG_MAX+1); + buf = malloc(10); + buf_alloc_size = 16; - result = recv(fd, *msg, MSG_MAX, 0); - if(result == -1) { - PERROR("recv"); - return -1; - } + for(;;) { + if(buf_used_size + RECV_INCREMENT > buf_alloc_size) { + buf_alloc_size *= 2; + buf = (char *) realloc(buf, buf_alloc_size); + } - (*msg)[result] = '\0'; - - DBG("ustcomm_app_recv_message: result is %d, message is %s", result, (*msg)); + /* FIXME: this is really inefficient; but with count>1 we would + * need a buffering mechanism */ + result = recv(fd, buf+buf_used_size, RECV_INCREMENT, 0); + if(result == -1) { + free(buf); + if(errno != ECONNRESET) + PERROR("recv"); + return -1; + } + if(result == 0) { + if(buf_used_size) + goto ret; + else { + free(buf); + return 0; + } + } + + + buf_used_size += result; + + if(buf[buf_used_size-1] == 0) { + goto ret; + } + } - if(src) - src->fd = fd; +ret: + *msg = buf; + DBG("received message \"%s\"", buf); return 1; + } int ustcomm_send_reply(struct ustcomm_server *server, char *msg, struct ustcomm_source *src) @@ -270,7 +315,10 @@ int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustco for(idx=1; idxfd = fds[idx].fd; + if(**msg == 0) { /* connection finished */ close(fds[idx].fd); @@ -393,29 +441,22 @@ int ustcomm_send_request(struct ustcomm_connection *conn, const char *req, char { int result; - result = send(conn->fd, req, strlen(req), MSG_NOSIGNAL); - if(result == -1) { - if(errno != EPIPE) - PERROR("send"); - return -1; - } + /* Send including the final \0 */ + result = send_message_fd(conn->fd, req); + if(result != 1) + return result; if(!reply) return 1; - *reply = (char *) malloc(MSG_MAX+1); - result = recv(conn->fd, *reply, MSG_MAX, 0); + result = recv_message_fd(conn->fd, reply); if(result == -1) { - if(errno != ECONNRESET) - PERROR("recv"); return -1; } else if(result == 0) { return 0; } - (*reply)[result] = '\0'; - return 1; } @@ -449,7 +490,7 @@ int ustcomm_connect_path(const char *path, struct ustcomm_connection *conn, pid_ result = connect(fd, (struct sockaddr *)&addr, sizeof(addr)); if(result == -1) { - PERROR("connect"); + PERROR("connect (path=%s)", path); return -1; } -- 2.34.1