Custom upgrade: chain load liblttng-ust-{fd,fork}.so.0 with dlopen

[lttng-ust.git] / src / lib / lttng-ust-fork / ustfork.c

diff --git a/src/lib/lttng-ust-fork/ustfork.c b/src/lib/lttng-ust-fork/ustfork.c
index 321ffc30c0fd993d7be43a62fa9063fbe3a2e5ca..ec6974b0cbf020c396c26540095a9a9e3d66565b 100644 (file)
--- a/src/lib/lttng-ust-fork/ustfork.c
+++ b/src/lib/lttng-ust-fork/ustfork.c
@@ -18,6 +18,223 @@
 
 #include <lttng/ust-fork.h>
 
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+static int (*__ust_before_fork)(sigset_t *save_sigset) = NULL;
+static int (*__ust_after_fork_child)(sigset_t *restore_sigset) = NULL;
+static int (*__ust_after_fork_parent)(sigset_t *restore_sigset) = NULL;
+
+static void (*__ust_after_setns)(void) = NULL;
+static void (*__ust_after_unshare)(void) = NULL;
+static void (*__ust_after_setuid)(void) = NULL;
+static void (*__ust_after_setgid)(void) = NULL;
+static void (*__ust_after_seteuid)(void) = NULL;
+static void (*__ust_after_setegid)(void) = NULL;
+static void (*__ust_after_setreuid)(void) = NULL;
+static void (*__ust_after_setregid)(void) = NULL;
+static void (*__ust_after_setresuid)(void) = NULL;
+static void (*__ust_after_setresgid)(void) = NULL;
+
+static
+void *_init_ust_before_fork(void)
+{
+       if (__ust_before_fork == NULL) {
+               __ust_before_fork = dlsym(RTLD_DEFAULT, "ust_before_fork");
+
+               if (__ust_before_fork == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_before_fork;
+}
+
+static
+void *_init_ust_after_fork_child(void)
+{
+       if (__ust_after_fork_child == NULL) {
+               __ust_after_fork_child = dlsym(RTLD_DEFAULT, "ust_after_fork_child");
+
+               if (__ust_after_fork_child == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_fork_child;
+}
+
+static
+void *_init_ust_after_fork_parent(void)
+{
+       if (__ust_after_fork_parent == NULL) {
+               __ust_after_fork_parent = dlsym(RTLD_DEFAULT, "ust_after_fork_parent");
+
+               if (__ust_after_fork_parent == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_fork_parent;
+}
+
+static
+void *_init_ust_after_setns(void)
+{
+       if (__ust_after_setns == NULL) {
+               __ust_after_setns = dlsym(RTLD_DEFAULT, "ust_after_setns");
+
+               if (__ust_after_setns == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_setns;
+}
+
+static
+void *_init_ust_after_unshare(void)
+{
+       if (__ust_after_unshare == NULL) {
+               __ust_after_unshare = dlsym(RTLD_DEFAULT, "ust_after_unshare");
+
+               if (__ust_after_unshare == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_unshare;
+}
+
+static
+void *_init_ust_after_setuid(void)
+{
+       if (__ust_after_setuid == NULL) {
+               __ust_after_setuid = dlsym(RTLD_DEFAULT, "ust_after_setuid");
+
+               if (__ust_after_setuid == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_setuid;
+}
+
+static
+void *_init_ust_after_setgid(void)
+{
+       if (__ust_after_setgid == NULL) {
+               __ust_after_setgid = dlsym(RTLD_DEFAULT, "ust_after_setgid");
+
+               if (__ust_after_setgid == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_setgid;
+}
+
+static
+void *_init_ust_after_seteuid(void)
+{
+       if (__ust_after_seteuid == NULL) {
+               __ust_after_seteuid = dlsym(RTLD_DEFAULT, "ust_after_seteuid");
+
+               if (__ust_after_seteuid == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_seteuid;
+}
+
+static
+void *_init_ust_after_setegid(void)
+{
+       if (__ust_after_setegid == NULL) {
+               __ust_after_setegid = dlsym(RTLD_DEFAULT, "ust_after_setegid");
+
+               if (__ust_after_setegid == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_setegid;
+}
+
+static
+void *_init_ust_after_setreuid(void)
+{
+       if (__ust_after_setreuid == NULL) {
+               __ust_after_setreuid = dlsym(RTLD_DEFAULT, "ust_after_setreuid");
+
+               if (__ust_after_setreuid == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_setreuid;
+}
+
+static
+void *_init_ust_after_setregid(void)
+{
+       if (__ust_after_setregid == NULL) {
+               __ust_after_setregid = dlsym(RTLD_DEFAULT, "ust_after_setregid");
+
+               if (__ust_after_setregid == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_setregid;
+}
+
+static
+void *_init_ust_after_setresuid(void)
+{
+       if (__ust_after_setresuid == NULL) {
+               __ust_after_setresuid = dlsym(RTLD_DEFAULT, "ust_after_setresuid");
+
+               if (__ust_after_setresuid == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_setresuid;
+}
+
+static
+void *_init_ust_after_setresgid(void)
+{
+       if (__ust_after_setresgid == NULL) {
+               __ust_after_setresgid = dlsym(RTLD_DEFAULT, "ust_after_setresgid");
+
+               if (__ust_after_setresgid == NULL) {
+                       fprintf(stderr, "%s\n", dlerror());
+               }
+       }
+
+       return __ust_after_setresgid;
+}
+
+static
+void _lttng_ust_fork_ctor(void)
+       __attribute__((constructor));
+static
+void _lttng_ust_fork_ctor(void)
+{
+       void *handle = NULL;
+
+       /*
+        * Load ust-2.12 in the global symbol namespace.
+        */
+       handle = dlopen("liblttng-ust.so.0", RTLD_GLOBAL | RTLD_NOW);
+       if (!handle) {
+               fprintf(stderr, "liblttng-ust-fork.so.1: Failed to dlopen liblttng-ust.so.0: %s\n", dlerror());
+               abort();
+       }
+}
+#endif
+
 pid_t fork(void)
 {
        static pid_t (*plibc_func)(void) = NULL;
@@ -35,14 +252,30 @@ pid_t fork(void)
        }
 
        lttng_ust_before_fork(&sigset);
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_before_fork()) {
+               __ust_before_fork(&sigset);
+       }
+#endif
+
        /* Do the real fork */
        retval = plibc_func();
        saved_errno = errno;
        if (retval == 0) {
                /* child */
                lttng_ust_after_fork_child(&sigset);
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+               if (_init_ust_after_fork_child()) {
+                       __ust_after_fork_child(&sigset);
+               }
+#endif
        } else {
                lttng_ust_after_fork_parent(&sigset);
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+               if (_init_ust_after_fork_parent()) {
+                       __ust_after_fork_parent(&sigset);
+               }
+#endif
        }
        errno = saved_errno;
        return retval;
@@ -65,15 +298,31 @@ int daemon(int nochdir, int noclose)
        }
 
        lttng_ust_before_fork(&sigset);
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_before_fork()) {
+               __ust_before_fork(&sigset);
+       }
+#endif
+
        /* 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);
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+               if (_init_ust_after_fork_child()) {
+                       __ust_after_fork_child(&sigset);
+               }
+#endif
        } else {
                /* on error in the parent */
                lttng_ust_after_fork_parent(&sigset);
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+               if (_init_ust_after_fork_parent()) {
+                       __ust_after_fork_parent(&sigset);
+               }
+#endif
        }
        errno = saved_errno;
        return retval;
@@ -99,6 +348,11 @@ int setuid(uid_t uid)
        saved_errno = errno;
 
        lttng_ust_after_setuid();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_setuid()) {
+               __ust_after_setuid();
+       }
+#endif
 
        errno = saved_errno;
        return retval;
@@ -124,6 +378,11 @@ int setgid(gid_t gid)
        saved_errno = errno;
 
        lttng_ust_after_setgid();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_setgid()) {
+               __ust_after_setgid();
+       }
+#endif
 
        errno = saved_errno;
        return retval;
@@ -149,6 +408,11 @@ int seteuid(uid_t euid)
        saved_errno = errno;
 
        lttng_ust_after_seteuid();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_seteuid()) {
+               __ust_after_seteuid();
+       }
+#endif
 
        errno = saved_errno;
        return retval;
@@ -174,6 +438,11 @@ int setegid(gid_t egid)
        saved_errno = errno;
 
        lttng_ust_after_setegid();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_setegid()) {
+               __ust_after_setegid();
+       }
+#endif
 
        errno = saved_errno;
        return retval;
@@ -199,6 +468,11 @@ int setreuid(uid_t ruid, uid_t euid)
        saved_errno = errno;
 
        lttng_ust_after_setreuid();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_setreuid()) {
+               __ust_after_setreuid();
+       }
+#endif
 
        errno = saved_errno;
        return retval;
@@ -224,6 +498,11 @@ int setregid(gid_t rgid, gid_t egid)
        saved_errno = errno;
 
        lttng_ust_after_setregid();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_setregid()) {
+               __ust_after_setregid();
+       }
+#endif
 
        errno = saved_errno;
        return retval;
@@ -245,6 +524,11 @@ static int clone_fn(void *arg)
 
        /* clone is now done and we are in child */
        lttng_ust_after_fork_child(&info->sigset);
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_fork_child()) {
+               __ust_after_fork_child(&info->sigset);
+       }
+#endif
        return info->fn(info->arg);
 }
 
@@ -290,11 +574,21 @@ int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...)
                struct ustfork_clone_info info = { .fn = fn, .arg = arg };
 
                lttng_ust_before_fork(&info.sigset);
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+               if (_init_ust_before_fork()) {
+                       __ust_before_fork(&info.sigset);
+               }
+#endif
                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);
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+               if (_init_ust_after_fork_parent()) {
+                       __ust_after_fork_parent(&info.sigset);
+               }
+#endif
        }
        errno = saved_errno;
        return retval;
@@ -320,6 +614,11 @@ int setns(int fd, int nstype)
        saved_errno = errno;
 
        lttng_ust_after_setns();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_setns()) {
+               __ust_after_setns();
+       }
+#endif
 
        errno = saved_errno;
        return retval;
@@ -345,6 +644,11 @@ int unshare(int flags)
        saved_errno = errno;
 
        lttng_ust_after_unshare();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_unshare()) {
+               __ust_after_unshare();
+       }
+#endif
 
        errno = saved_errno;
        return retval;
@@ -370,6 +674,11 @@ int setresuid(uid_t ruid, uid_t euid, uid_t suid)
        saved_errno = errno;
 
        lttng_ust_after_setresuid();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_setresuid()) {
+               __ust_after_setresuid();
+       }
+#endif
 
        errno = saved_errno;
        return retval;
@@ -395,6 +704,11 @@ int setresgid(gid_t rgid, gid_t egid, gid_t sgid)
        saved_errno = errno;
 
        lttng_ust_after_setresgid();
+#if !defined(LTTNG_UST_CUSTOM_UPGRADE_CONFLICTING_SYMBOLS)
+       if (_init_ust_after_setresgid()) {
+               __ust_after_setresgid();
+       }
+#endif
 
        errno = saved_errno;
        return retval;