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 07912a7d68bf7ce97cf7ba765194fd66e28334c8..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 {
@@ -154,14 +167,14 @@ int child_run_as(void *_data)
        if (data->gid != getegid()) {
                ret = setegid(data->gid);
                if (ret < 0) {
-                       perror("setegid");
+                       PERROR("setegid");
                        return EXIT_FAILURE;
                }
        }
        if (data->uid != geteuid()) {
                ret = seteuid(data->uid);
                if (ret < 0) {
-                       perror("seteuid");
+                       PERROR("seteuid");
                        return EXIT_FAILURE;
                }
        }
@@ -177,7 +190,7 @@ int child_run_as(void *_data)
                writelen = write(data->retval_pipe, &sendret.c[index],
                                writeleft);
                if (writelen < 0) {
-                       perror("write");
+                       PERROR("write");
                        return EXIT_FAILURE;
                }
                writeleft -= writelen;
@@ -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;
@@ -214,7 +227,8 @@ int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
 
        ret = pipe(retval_pipe);
        if (ret < 0) {
-               perror("pipe");
+               PERROR("pipe");
+               retval.i = ret;
                goto end;
        }
        run_as_data.data = data;
@@ -224,23 +238,22 @@ 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");
-               ret = -ENOMEM;
+               PERROR("mmap");
+               retval.i = -ENOMEM;
                goto close_pipe;
        }
        /*
         * 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");
-               ret = pid;
+               PERROR("clone");
+               retval.i = pid;
                goto unmap_stack;
        }
        /* receive return value */
@@ -249,7 +262,7 @@ int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
        do {
                readlen = read(retval_pipe[0], &retval.c[index], readleft);
                if (readlen < 0) {
-                       perror("read");
+                       PERROR("read");
                        ret = -1;
                        break;
                }
@@ -263,21 +276,51 @@ int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
         */
        pid = waitpid(pid, &status, 0);
        if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
-               perror("wait");
-               ret = -1;
+               PERROR("wait");
+               retval.i = -1;
        }
 unmap_stack:
        ret = munmap(child_stack, RUNAS_CHILD_STACK_SIZE);
        if (ret < 0) {
-               perror("munmap");
+               PERROR("munmap");
+               retval.i = ret;
        }
 close_pipe:
-       close(retval_pipe[0]);
-       close(retval_pipe[1]);
+       ret = close(retval_pipe[0]);
+       if (ret) {
+               PERROR("close");
+       }
+       ret = close(retval_pipe[1]);
+       if (ret) {
+               PERROR("close");
+       }
 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;