On Apr 1, 2011, at 10:24 PM, Mathieu Desnoyers wrote:
* Nils Carlson ([email protected]) wrote:On Apr 1, 2011, at 5:14 PM, Mathieu Desnoyers wrote:* Nils Carlson ([email protected]) wrote:This patch removes all references to usterr.h and functions inusterr.h from libustctl and ustcomm. This is done for three reasons:1. DBG, ERR, PERROR etc call in ust_safe_snprintf, I don't know why, and I can't figure out any good reasons. If somebody can enlighten me I would be very grateful. The only thing I can figure out is that these are some sort of "signal safe" printf.Yep, that's right.2. All this stuff is quite stable and working and libraries really shouldn't be printing stuff.What I disagree about the patch below is that you are removing debug error printouts without taking care of some of the error values in many cases (just ignoring them).So we start from a dubtious behavior (debug error messages was not theproper way to handle error values; they should rather have been treatedand pushed to the callers), to just ignoring the errors, which is kindof bad, you know... ;)So I would expect that all the error values you remove debug messagesfrom should be dealt with rather than ignored.Hm. errno's are still there... As long as errnos aren't overwritten theycan still be used. Can't find anywhere where we are making calls that should overwrite errnos. We could try to introduce consistency in returning negative errno's though. That would be a separate patch.Well, could do that... but as noted, this is pretty stable stuff and we3. This allows me to compile lttng-tools without linking libustctl to the ust_snprintf family of functions. This makes me happy.Well, you could just create a set of debug macros that use the standard printf, and decide at compile-time if the log output is built or notwith these pretty simple macros. This change would make more sense tome than removing the debugging code we have there.can add debug code as needed I think.More comments below,Mathieu, enlighten me as best you can... :-) Signed-off-by: Nils Carlson <[email protected]> --- libustcomm/ustcomm.c | 52 ++++ +------------------------------------------- libustctl/libustctl.c | 13 ++--------- 2 files changed, 9 insertions(+), 56 deletions(-) diff --git a/libustcomm/ustcomm.c b/libustcomm/ustcomm.c index dcf8cd8..2a5acc7 100644 --- a/libustcomm/ustcomm.c +++ b/libustcomm/ustcomm.c @@ -29,13 +29,14 @@ #include <sys/epoll.h> #include <sys/stat.h> +#include <stdarg.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <execinfo.h> #include "ustcomm.h" -#include "usterr.h" +#include <ust/core.h> #include "share.h" static int mkdir_p(const char *path, mode_t mode) @@ -101,7 +102,6 @@ static struct sockaddr_un * create_sock_addr(const char *name, addr = malloc(alloc_size); if (addr < 0) {Hrm, the original test is bogus there ? malloc returns NULL if alloc fails, not a negative value... ?True... Could fix that in a seperate patch.- ERR("allocating addr failed"); return NULL; }@@ -149,9 +149,7 @@ void ustcomm_del_sock(struct ustcomm_sock *sock,int keep_in_epoll) { cds_list_del(&sock->list); if (!keep_in_epoll) { - if (epoll_ctl(sock->epoll_fd, EPOLL_CTL_DEL, sock->fd, NULL) == -1) { - PERROR("epoll_ctl: failed to delete socket"); - } + epoll_ctl(sock->epoll_fd, EPOLL_CTL_DEL, sock->fd, NULL);I think we should keep the error value test here ?No, EPOLL_CTL_DEL can only return error ENONENT, if there was no fd withthat fd number, in which cas everything anyway is fine.This is the kind of obvious safety net we should leave in place. It's not because we expect that we'll always pass a valid FD that we won't have a bug creeping in at some point, and checking the returned errorvalue is the kind of safety measure that will help us diagnose problemsmuch more quickly in the long run.
hm. Remember, this is a tracing library. It should be quiet.What do you suggest we do with the error? the function doesn't return anything. The only thing we can do is spew out a error message, which if we are lucky may be reported, probably be ignored, and in worst case screw up a program using stdout/stderr for something.
Maybe we should discuss this though. What should UST do/not-do. Should UST ever throw stuff out on stdout/stderr?
} close(sock->fd); free(sock); @@ -168,13 +166,11 @@ struct ustcomm_sock * ustcomm_init_named_socket(const char *name, fd = socket(PF_UNIX, SOCK_STREAM, 0); if(fd == -1) { - PERROR("socket"); return NULL; } addr = create_sock_addr(name, &sock_addr_size); if (addr == NULL) { - ERR("allocating addr, UST thread bailing"); goto close_sock; } @@ -182,29 +178,24 @@ struct ustcomm_sock * ustcomm_init_named_socket(const char *name, if(result == 0) { /* file exists */ result = unlink(name); - if(result == -1) { - PERROR("unlink of socket file"); + if (result == -1) { goto free_addr; } - DBG("socket already exists; overwriting"); } result = bind(fd, (struct sockaddr *)addr, sock_addr_size); if(result == -1) { - PERROR("bind"); goto free_addr; } result = listen(fd, 1); if(result == -1) { - PERROR("listen"); goto free_addr; } sock = ustcomm_init_sock(fd, epoll_fd, NULL); if (!sock) { - ERR("failed to create ustcomm_sock"); goto free_addr; } @@ -236,39 +227,31 @@ void ustcomm_del_named_sock(struct ustcomm_sock *sock, /* Get the socket name */ alloc_size = sizeof(dummy); if (getsockname(fd, &dummy, (socklen_t *)&alloc_size) < 0) { - PERROR("getsockname failed"); goto del_sock; } sockaddr = zmalloc(alloc_size); if (!sockaddr) { - ERR("failed to allocate sockaddr"); goto del_sock; } if (getsockname(fd, sockaddr, (socklen_t *)&alloc_size) < 0) { - PERROR("getsockname failed"); goto free_sockaddr; } /* Destroy socket */ result = stat(sockaddr->sun_path, &st); if(result < 0) { - PERROR("stat (%s)", sockaddr->sun_path); goto free_sockaddr; } /* Paranoid check before deleting. */ result = S_ISSOCK(st.st_mode); if(!result) { - ERR("The socket we are about to delete is not a socket."); goto free_sockaddr; } - result = unlink(sockaddr->sun_path); - if(result < 0) { - PERROR("unlink"); - } + unlink(sockaddr->sun_path);Should we do something with the error here ? Why is it not treated (ifthere is a reason, we should add a comment)hm, could add a comment but not much point. This is just cleanup afterall, if it fails we can't do anything about it and it won't affect anything.I recommend this to ensure that all return values are either - treated, or - documented.looking at unlink(2), there are many reasons why unlink can fail. If it fails due to incorrect access rights (for instance), we probably want topropagate the error up to the user, no ?
For what? Nothing the user can/should do anyway. /Nils
Thanks, Mathieu/NilsThanks, Mathieu} free_sockaddr: @@ -297,7 +280,6 @@ int ustcomm_recv_alloc(int sock, } else if (errno == EINTR) { return -1; } else if (result < 0) { - PERROR("recv"); return -1; } return 0; @@ -326,7 +308,6 @@ int ustcomm_recv_alloc(int sock, result = recvmsg(sock, &msg, MSG_WAITALL); if (result < 0) { free(*data); - PERROR("recvmsg failed"); } return result; @@ -355,7 +336,6 @@ int ustcomm_recv_fd(int sock, } else if (errno == EINTR) { return -1; } else if (result < 0) { - PERROR("recv"); return -1; } return 0; @@ -372,7 +352,6 @@ int ustcomm_recv_fd(int sock, if (peek_header.size && data) { if (peek_header.size < 0 || peek_header.size > USTCOMM_DATA_SIZE) { - ERR("big peek header! %ld", peek_header.size); return 0; } @@ -389,9 +368,6 @@ int ustcomm_recv_fd(int sock, result = recvmsg(sock, &msg, MSG_WAITALL); if (result <= 0) { - if (result < 0) { - PERROR("recvmsg failed"); - } return result; } @@ -407,9 +383,6 @@ int ustcomm_recv_fd(int sock, } cmsg = CMSG_NXTHDR(&msg, cmsg); } - if (!result) { - ERR("Failed to receive file descriptor\n"); - } } return 1; @@ -430,7 +403,6 @@ int ustcomm_send_fd(int sock, { struct iovec iov[2]; struct msghdr msg; - int result; struct cmsghdr *cmsg; char buf[CMSG_SPACE(sizeof(int))]; @@ -461,11 +433,7 @@ int ustcomm_send_fd(int sock, msg.msg_controllen = cmsg->cmsg_len; } - result = sendmsg(sock, &msg, MSG_NOSIGNAL); - if (result < 0 && errno != EPIPE) { - PERROR("sendmsg failed"); - } - return result; + return sendmsg(sock, &msg, MSG_NOSIGNAL); } int ustcomm_send(int sock,@@ -504,19 +472,16 @@ int ustcomm_connect_path(const char *name, int*connection_fd) fd = socket(PF_UNIX, SOCK_STREAM, 0); if(fd == -1) { - PERROR("socket"); return -1; } addr = create_sock_addr(name, &sock_addr_size); if (addr == NULL) { - ERR("allocating addr failed"); goto close_sock; } result = connect(fd, (struct sockaddr *)addr, sock_addr_size); if(result == -1) { - PERROR("connect (path=%s)", name); goto free_sock_addr; } @@ -543,7 +508,6 @@ char *ustcomm_user_sock_dir(void) result = asprintf(&sock_dir, "%s%s", USER_SOCK_DIR, cuserid(NULL)); if (result < 0) { - ERR("string overflow allocating directory name"); return NULL; }@@ -569,14 +533,12 @@ static int connect_app_non_root(pid_t pid, int*app_fd) result = asprintf(&sock_name, "%s/%d", dir_name, pid); if (result < 0) { - ERR("failed to allocate socket name"); retval = -1; goto free_dir_name; } result = ustcomm_connect_path(sock_name, app_fd); if (result < 0) { - ERR("failed to connect to app"); retval = -1; goto free_sock_name; } @@ -657,14 +619,12 @@ int ensure_dir_exists(const char *dir, mode_t mode) result = mkdir_p(dir, mode); if(result != 0) { - ERR("executing in recursive creation of directory %s", dir); return -1; } } else { if (st.st_mode != mode) { result = chmod(dir, mode); if (result < 0) { - ERR("couldn't set directory mode on %s", dir); return -1; } } diff --git a/libustctl/libustctl.c b/libustctl/libustctl.c index 1911434..b5d6a02 100644 --- a/libustctl/libustctl.c +++ b/libustctl/libustctl.c @@ -17,6 +17,7 @@ */ #define _GNU_SOURCE +#include <errno.h> #include <stdio.h> #include <unistd.h> #include <getopt.h> @@ -26,8 +27,8 @@ #include <dirent.h> #include "ustcomm.h" -#include "ust/ustctl.h" -#include "usterr.h" +#include <ust/ustctl.h> +#include <ust/core.h> static int do_cmd(int sock, const struct ustcomm_header *req_header, @@ -57,7 +58,6 @@ static int do_cmd(int sock, } } } else { - ERR("ustcomm req failed"); if (result == 0) { saved_errno = ENOTCONN; } else { @@ -80,7 +80,6 @@ int ustctl_connect_pid(pid_t pid) int sock; if (ustcomm_connect_app(pid, &sock)) { - ERR("could not connect to PID %u", (unsigned int) pid); errno = ENOTCONN; return -1; } @@ -580,20 +579,17 @@ int ustctl_get_cmsf(int sock, struct marker_status **cmsf) result = ustcomm_send(sock, &req_header, NULL); if (result <= 0) { - PERROR("error while requesting markers list"); return -1; } result = ustcomm_recv_alloc(sock, &res_header, &big_str); if (result <= 0) { - ERR("error while receiving markers list"); return -1; } tmp_cmsf = (struct marker_status *) zmalloc(sizeof(struct marker_status) * (ustctl_count_nl(big_str) + 1)); if (tmp_cmsf == NULL) { - ERR("Failed to allocate CMSF array"); return -1; } @@ -672,13 +668,11 @@ int ustctl_get_tes(int sock, struct trace_event_status **tes) result = ustcomm_send(sock, &req_header, NULL); if (result != 1) { - ERR("error while requesting trace_event list"); return -1; } result = ustcomm_recv_alloc(sock, &res_header, &big_str); if (result != 1) { - ERR("error while receiving markers list"); return -1; } @@ -686,7 +680,6 @@ int ustctl_get_tes(int sock, struct trace_event_status **tes) zmalloc(sizeof(struct trace_event_status) * (ustctl_count_nl(big_str) + 1)); if (tmp_tes == NULL) { - ERR("Failed to allocate TES array"); return -1; } -- 1.7.1 _______________________________________________ ltt-dev mailing list [email protected] http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev-- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com _______________________________________________ ltt-dev mailing list [email protected] http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev-- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com
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