| Message ID | 1373365612-16402-1-git-send-email-nicolas.dichtel@6wind.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | stephen hemminger |
| Headers | show |
On Tue, 2013-07-09 at 12:26 +0200, Nicolas Dichtel wrote: > From: JunweiZhang <junwei.zhang@6wind.com> > > execvp() does not return when the command succeed, hence all commands in the > batch file after the line 'ip netns exec' are not executed. > > Let's fork before calling execvp(). > > Example: > $ cat test.batch > netns add netns1 > netns exec netns1 ip l > netns > $ ip -b test.batch > 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULT > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 > 2: sit0: <NOARP> mtu 1480 qdisc noop state DOWN mode DEFAULT > link/sit 0.0.0.0 brd 0.0.0.0 > > All command after 'netns exec' are never executed. > > With the patch: > $ ip -b test.batch > 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULT > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 > 2: sit0: <NOARP> mtu 1480 qdisc noop state DOWN mode DEFAULT > link/sit 0.0.0.0 brd 0.0.0.0 > netns1 > > Now, existing netns are displayed. > > Signed-off-by: JunweiZhang <junwei.zhang@6wind.com> > Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> > --- > > v3: be more verbose on error (fork(), waitpid()) > when child fails, just exit to avoid double cleanning > check WIFEXITED() and waitpid() before using WEXITSTATUS() > > v2: keep exit status of the child > add an example in the commit log > > ip/ipnetns.c | 30 +++++++++++++++++++++++++++--- > 1 file changed, 27 insertions(+), 3 deletions(-) > > diff --git a/ip/ipnetns.c b/ip/ipnetns.c > index fa2b681..474a296 100644 > --- a/ip/ipnetns.c > +++ b/ip/ipnetns.c > @@ -138,6 +138,7 @@ static int netns_exec(int argc, char **argv) > const char *name, *cmd; > char net_path[MAXPATHLEN]; > int netns; > + int pid, status; pid_t pid; > > if (argc < 1) { > fprintf(stderr, "No netns name specified\n"); > @@ -185,9 +186,32 @@ static int netns_exec(int argc, char **argv) > /* Setup bind mounts for config files in /etc */ > bind_etc(name); > > - if (execvp(cmd, argv + 1) < 0) > - fprintf(stderr, "exec of \"%s\" failed: %s\n", > - cmd, strerror(errno)); > + pid = fork(); > + if (pid < 0) { > + perror("fork"); > + return EXIT_FAILURE; > + } else if (pid == 0) { > + /* Child */ > + if (execvp(cmd, argv + 1) < 0) > + fprintf(stderr, "exec of \"%s\" failed: %s\n", > + cmd, strerror(errno)); > + exit(EXIT_FAILURE); _exit(EXIT_FAILURE); Or else you could have buffered data in stdout buffer, and it will be emitted twice. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/ip/ipnetns.c b/ip/ipnetns.c index fa2b681..474a296 100644 --- a/ip/ipnetns.c +++ b/ip/ipnetns.c @@ -138,6 +138,7 @@ static int netns_exec(int argc, char **argv) const char *name, *cmd; char net_path[MAXPATHLEN]; int netns; + int pid, status; if (argc < 1) { fprintf(stderr, "No netns name specified\n"); @@ -185,9 +186,32 @@ static int netns_exec(int argc, char **argv) /* Setup bind mounts for config files in /etc */ bind_etc(name); - if (execvp(cmd, argv + 1) < 0) - fprintf(stderr, "exec of \"%s\" failed: %s\n", - cmd, strerror(errno)); + pid = fork(); + if (pid < 0) { + perror("fork"); + return EXIT_FAILURE; + } else if (pid == 0) { + /* Child */ + if (execvp(cmd, argv + 1) < 0) + fprintf(stderr, "exec of \"%s\" failed: %s\n", + cmd, strerror(errno)); + exit(EXIT_FAILURE); + } + + /* Parent */ + if (waitpid(pid, &status, 0) < 0) { + perror("waitpid"); + return EXIT_FAILURE; + } + + if (WIFEXITED(status)) { + /* ip must returns the status of the child, but do_cmd() will + * add a minus to this returned value, so let's add another one + * here to cancel it. + */ + return -WEXITSTATUS(status); + } + return EXIT_FAILURE; }