Merge branch 'master' of git://git.lttng.org/lttng-tools

[lttng-tools.git] / src / common / runas.c

diff --git a/src/common/runas.c b/src/common/runas.c
index 60e02a2bf85a4e22ff363d2a6ede3cfc1a0fd277..e0c317c4e40347fb7001b74fb9900e9bcfafe32f 100644 (file)
--- a/src/common/runas.c
+++ b/src/common/runas.c
@@ -28,16 +28,29 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <sched.h>
-#include <sys/mman.h>
+#include <sys/signal.h>
 
 #include <common/error.h>
+#include <common/compat/mman.h>
+#include <common/compat/clone.h>
 
 #include "runas.h"
 
 #define RUNAS_CHILD_STACK_SIZE 10485760
 
-#ifndef MAP_STACK
-#define MAP_STACK              0
+#ifdef __FreeBSD__
+/* FreeBSD MAP_STACK always return -ENOMEM */
+#define LTTNG_MAP_STACK                0
+#else
+#define LTTNG_MAP_STACK                MAP_STACK
+#endif
+
+#ifndef MAP_GROWSDOWN
+#define MAP_GROWSDOWN          0
+#endif
+
+#ifndef MAP_ANONYMOUS
+#define MAP_ANONYMOUS          MAP_ANON
 #endif
 
 struct run_as_data {
@@ -187,7 +200,7 @@ int child_run_as(void *_data)
 }
 
 static
-int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
+int run_as_clone(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
 {
        struct run_as_data run_as_data;
        int ret = 0;
@@ -225,7 +238,7 @@ int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
        run_as_data.retval_pipe = retval_pipe[1];       /* write end */
        child_stack = mmap(NULL, RUNAS_CHILD_STACK_SIZE,
                PROT_WRITE | PROT_READ,
-               MAP_PRIVATE | MAP_GROWSDOWN | MAP_ANONYMOUS | MAP_STACK,
+               MAP_PRIVATE | MAP_GROWSDOWN | MAP_ANONYMOUS | LTTNG_MAP_STACK,
                -1, 0);
        if (child_stack == MAP_FAILED) {
                PERROR("mmap");
@@ -236,9 +249,8 @@ int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
         * Pointing to the middle of the stack to support architectures
         * where the stack grows up (HPPA).
         */
-       pid = clone(child_run_as, child_stack + (RUNAS_CHILD_STACK_SIZE / 2),
-               CLONE_FILES | SIGCHLD,
-               &run_as_data, NULL);
+       pid = lttng_clone_files(child_run_as, child_stack + (RUNAS_CHILD_STACK_SIZE / 2),
+               &run_as_data);
        if (pid < 0) {
                PERROR("clone");
                retval.i = pid;
@@ -286,6 +298,29 @@ end:
        return retval.i;
 }
 
+/*
+ * To be used on setups where gdb has issues debugging programs using
+ * clone/rfork. Note that this is for debuging ONLY, and should not be
+ * considered secure.
+ */
+static
+int run_as_noclone(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
+{
+       return cmd(data);
+}
+
+static
+int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
+{
+       if (!getenv("LTTNG_DEBUG_NOCLONE")) {
+               DBG("Using run_as_clone");
+               return run_as_clone(cmd, data, uid, gid);
+       } else {
+               DBG("Using run_as_noclone");
+               return run_as_noclone(cmd, data, uid, gid);
+       }
+}
+
 int run_as_mkdir_recursive(const char *path, mode_t mode, uid_t uid, gid_t gid)
 {
        struct run_as_mkdir_data data;