--- /dev/null
+/*
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
+ * Copyright (C) 2009 Pierre-Marc Fournier
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+/* Has to be included first to override dlfcn.h */
+#include <common/compat/dlfcn.h>
+
+#include <unistd.h>
+#include <stdio.h>
+#include <signal.h>
+#include <sched.h>
+#include <stdarg.h>
+#include <errno.h>
+
+#include <lttng/ust-fork.h>
+
+pid_t fork(void)
+{
+ 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, "fork");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"fork\" symbol\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ lttng_ust_before_fork(&sigset);
+ /* Do the real fork */
+ retval = plibc_func();
+ saved_errno = errno;
+ if (retval == 0) {
+ /* child */
+ lttng_ust_after_fork_child(&sigset);
+ } else {
+ lttng_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;
+ }
+ }
+
+ lttng_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 */
+ lttng_ust_after_fork_child(&sigset);
+ } else {
+ /* on error in the parent */
+ lttng_ust_after_fork_parent(&sigset);
+ }
+ errno = saved_errno;
+ return retval;
+}
+
+int setuid(uid_t uid)
+{
+ static int (*plibc_func)(uid_t uid) = NULL;
+ int retval;
+ int saved_errno;
+
+ if (plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "setuid");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"setuid\" symbol\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ /* Do the real setuid */
+ retval = plibc_func(uid);
+ saved_errno = errno;
+
+ lttng_ust_after_setuid();
+
+ errno = saved_errno;
+ return retval;
+}
+
+int setgid(gid_t gid)
+{
+ static int (*plibc_func)(gid_t gid) = NULL;
+ int retval;
+ int saved_errno;
+
+ if (plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "setgid");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"setgid\" symbol\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ /* Do the real setgid */
+ retval = plibc_func(gid);
+ saved_errno = errno;
+
+ lttng_ust_after_setgid();
+
+ errno = saved_errno;
+ return retval;
+}
+
+int seteuid(uid_t euid)
+{
+ static int (*plibc_func)(uid_t euid) = NULL;
+ int retval;
+ int saved_errno;
+
+ if (plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "seteuid");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"seteuid\" symbol\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ /* Do the real seteuid */
+ retval = plibc_func(euid);
+ saved_errno = errno;
+
+ lttng_ust_after_seteuid();
+
+ errno = saved_errno;
+ return retval;
+}
+
+int setegid(gid_t egid)
+{
+ static int (*plibc_func)(gid_t egid) = NULL;
+ int retval;
+ int saved_errno;
+
+ if (plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "setegid");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"setegid\" symbol\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ /* Do the real setegid */
+ retval = plibc_func(egid);
+ saved_errno = errno;
+
+ lttng_ust_after_setegid();
+
+ errno = saved_errno;
+ return retval;
+}
+
+int setreuid(uid_t ruid, uid_t euid)
+{
+ static int (*plibc_func)(uid_t ruid, uid_t euid) = NULL;
+ int retval;
+ int saved_errno;
+
+ if (plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "setreuid");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"setreuid\" symbol\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ /* Do the real setreuid */
+ retval = plibc_func(ruid, euid);
+ saved_errno = errno;
+
+ lttng_ust_after_setreuid();
+
+ errno = saved_errno;
+ return retval;
+}
+
+int setregid(gid_t rgid, gid_t egid)
+{
+ static int (*plibc_func)(gid_t rgid, gid_t egid) = NULL;
+ int retval;
+ int saved_errno;
+
+ if (plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "setregid");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"setregid\" symbol\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ /* Do the real setregid */
+ retval = plibc_func(rgid, egid);
+ saved_errno = errno;
+
+ lttng_ust_after_setregid();
+
+ errno = saved_errno;
+ return retval;
+}
+
+#ifdef __linux__
+
+struct user_desc;
+
+struct ustfork_clone_info {
+ int (*fn)(void *);
+ void *arg;
+ sigset_t sigset;
+};
+
+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 */
+ lttng_ust_after_fork_child(&info->sigset);
+ return info->fn(info->arg);
+}
+
+int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...)
+{
+ static int (*plibc_func)(int (*fn)(void *), void *child_stack,
+ int flags, void *arg, pid_t *ptid,
+ struct user_desc *tls, pid_t *ctid) = NULL;
+ /* var args */
+ pid_t *ptid;
+ struct user_desc *tls;
+ pid_t *ctid;
+ /* end of var args */
+ va_list ap;
+ int retval;
+ int saved_errno;
+
+ va_start(ap, arg);
+ ptid = va_arg(ap, pid_t *);
+ tls = va_arg(ap, struct user_desc *);
+ ctid = va_arg(ap, pid_t *);
+ va_end(ap);
+
+ if (plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "clone");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"clone\" symbol.\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ if (flags & CLONE_VM) {
+ /*
+ * Creating a thread, no need to intervene, just pass on
+ * the arguments.
+ */
+ 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 };
+
+ lttng_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. */
+ lttng_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;
+
+ lttng_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;
+
+ lttng_ust_after_unshare();
+
+ errno = saved_errno;
+ return retval;
+}
+
+int setresuid(uid_t ruid, uid_t euid, uid_t suid)
+{
+ static int (*plibc_func)(uid_t ruid, uid_t euid, uid_t suid) = NULL;
+ int retval;
+ int saved_errno;
+
+ if (plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "setresuid");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"setresuid\" symbol\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ /* Do the real setresuid */
+ retval = plibc_func(ruid, euid, suid);
+ saved_errno = errno;
+
+ lttng_ust_after_setresuid();
+
+ errno = saved_errno;
+ return retval;
+}
+
+int setresgid(gid_t rgid, gid_t egid, gid_t sgid)
+{
+ static int (*plibc_func)(gid_t rgid, gid_t egid, gid_t sgid) = NULL;
+ int retval;
+ int saved_errno;
+
+ if (plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "setresgid");
+ if (plibc_func == NULL) {
+ fprintf(stderr, "libustfork: unable to find \"setresgid\" symbol\n");
+ errno = ENOSYS;
+ return -1;
+ }
+ }
+
+ /* Do the real setresgid */
+ retval = plibc_func(rgid, egid, sgid);
+ saved_errno = errno;
+
+ lttng_ust_after_setresgid();
+
+ 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;
+ }
+ }
+
+ lttng_ust_before_fork(&sigset);
+ /* Do the real rfork */
+ retval = plibc_func();
+ saved_errno = errno;
+ if (retval == 0) {
+ /* child */
+ lttng_ust_after_fork_child(&sigset);
+ } else {
+ lttng_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
projects / lttng-ust.git / blobdiff