X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust-fork%2Fustfork.c;h=25f9d4cc04c31d2589e36d148684bf61d846c5aa;hb=735bef4705cc42f25d26f25be09ba98f1efb8511;hp=5e6acba16e87fb9893ee7c9fe3b756afae12dd38;hpb=69400ac4a4e6575f749c6326df7c2a2c8ac3bdc5;p=lttng-ust.git diff --git a/liblttng-ust-fork/ustfork.c b/liblttng-ust-fork/ustfork.c index 5e6acba1..25f9d4cc 100644 --- a/liblttng-ust-fork/ustfork.c +++ b/liblttng-ust-fork/ustfork.c @@ -1,6 +1,6 @@ /* * Copyright (C) 2009 Pierre-Marc Fournier - * Copyright (C) 2011 Mathieu Desnoyers + * Copyright (C) 2011-2012 Mathieu Desnoyers * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -18,48 +18,85 @@ */ #define _GNU_SOURCE -#include +#include #include #include #include #include #include -#include "usterr.h" +#include #include -struct user_desc; - pid_t fork(void) { static pid_t (*plibc_func)(void) = NULL; - ust_fork_info_t fork_info; + sigset_t sigset; pid_t retval; + int saved_errno; if (plibc_func == NULL) { plibc_func = dlsym(RTLD_NEXT, "fork"); if (plibc_func == NULL) { fprintf(stderr, "libustfork: unable to find \"fork\" symbol\n"); + errno = ENOSYS; return -1; } } - ust_before_fork(&fork_info); + ust_before_fork(&sigset); /* Do the real fork */ retval = plibc_func(); + saved_errno = errno; if (retval == 0) { /* child */ - ust_after_fork_child(&fork_info); + ust_after_fork_child(&sigset); + } else { + ust_after_fork_parent(&sigset); + } + errno = saved_errno; + return retval; +} + +int daemon(int nochdir, int noclose) +{ + static int (*plibc_func)(int nochdir, int noclose) = NULL; + sigset_t sigset; + int retval; + int saved_errno; + + if (plibc_func == NULL) { + plibc_func = dlsym(RTLD_NEXT, "daemon"); + if (plibc_func == NULL) { + fprintf(stderr, "libustfork: unable to find \"daemon\" symbol\n"); + errno = ENOSYS; + return -1; + } + } + + ust_before_fork(&sigset); + /* Do the real daemon call */ + retval = plibc_func(nochdir, noclose); + saved_errno = errno; + if (retval == 0) { + /* child, parent called _exit() directly */ + ust_after_fork_child(&sigset); } else { - ust_after_fork_parent(&fork_info); + /* on error in the parent */ + ust_after_fork_parent(&sigset); } + errno = saved_errno; return retval; } +#ifdef __linux__ + +struct user_desc; + struct ustfork_clone_info { int (*fn)(void *); void *arg; - ust_fork_info_t fork_info; + sigset_t sigset; }; static int clone_fn(void *arg) @@ -67,7 +104,7 @@ static int clone_fn(void *arg) struct ustfork_clone_info *info = (struct ustfork_clone_info *) arg; /* clone is now done and we are in child */ - ust_after_fork_child(&info->fork_info); + ust_after_fork_child(&info->sigset); return info->fn(info->arg); } @@ -83,6 +120,7 @@ int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...) /* end of var args */ va_list ap; int retval; + int saved_errno; va_start(ap, arg); ptid = va_arg(ap, pid_t *); @@ -94,6 +132,7 @@ int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...) plibc_func = dlsym(RTLD_NEXT, "clone"); if (plibc_func == NULL) { fprintf(stderr, "libustfork: unable to find \"clone\" symbol.\n"); + errno = ENOSYS; return -1; } } @@ -105,15 +144,110 @@ int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...) */ retval = plibc_func(fn, child_stack, flags, arg, ptid, tls, ctid); + saved_errno = errno; } else { /* Creating a real process, we need to intervene. */ - struct ustfork_clone_info info = { fn: fn, arg: arg }; + struct ustfork_clone_info info = { .fn = fn, .arg = arg }; - ust_before_fork(&info.fork_info); + ust_before_fork(&info.sigset); retval = plibc_func(clone_fn, child_stack, flags, &info, ptid, tls, ctid); + saved_errno = errno; /* The child doesn't get here. */ - ust_after_fork_parent(&info.fork_info); + ust_after_fork_parent(&info.sigset); + } + errno = saved_errno; + return retval; +} + +int setns(int fd, int nstype) +{ + static int (*plibc_func)(int fd, int nstype) = NULL; + int retval; + int saved_errno; + + if (plibc_func == NULL) { + plibc_func = dlsym(RTLD_NEXT, "setns"); + if (plibc_func == NULL) { + fprintf(stderr, "libustfork: unable to find \"setns\" symbol\n"); + errno = ENOSYS; + return -1; + } } + + /* Do the real setns */ + retval = plibc_func(fd, nstype); + saved_errno = errno; + + ust_after_setns(); + + errno = saved_errno; return retval; } + +int unshare(int flags) +{ + static int (*plibc_func)(int flags) = NULL; + int retval; + int saved_errno; + + if (plibc_func == NULL) { + plibc_func = dlsym(RTLD_NEXT, "unshare"); + if (plibc_func == NULL) { + fprintf(stderr, "libustfork: unable to find \"unshare\" symbol\n"); + errno = ENOSYS; + return -1; + } + } + + /* Do the real setns */ + retval = plibc_func(flags); + saved_errno = errno; + + ust_after_unshare(); + + errno = saved_errno; + return retval; +} + +#elif defined (__FreeBSD__) + +pid_t rfork(int flags) +{ + static pid_t (*plibc_func)(void) = NULL; + sigset_t sigset; + pid_t retval; + int saved_errno; + + if (plibc_func == NULL) { + plibc_func = dlsym(RTLD_NEXT, "rfork"); + if (plibc_func == NULL) { + fprintf(stderr, "libustfork: unable to find \"rfork\" symbol\n"); + errno = ENOSYS; + return -1; + } + } + + ust_before_fork(&sigset); + /* Do the real rfork */ + retval = plibc_func(); + saved_errno = errno; + if (retval == 0) { + /* child */ + ust_after_fork_child(&sigset); + } else { + ust_after_fork_parent(&sigset); + } + errno = saved_errno; + return retval; +} + +/* + * On BSD, no need to override vfork, because it runs in the context of + * the parent, with parent waiting until execve or exit is executed in + * the child. + */ + +#else +#warning "Unknown OS. You might want to ensure that fork/clone/vfork/fork handling is complete." +#endif