run_as: add extract ELF symbol offset command

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

diff --git a/src/common/runas.c b/src/common/runas.c
index 863e824283fccfb159fad9150d859317e596618d..bed25a46368d61d875939acd1461e0b98a3af4cb 100644 (file)
--- a/src/common/runas.c
+++ b/src/common/runas.c
@@ -38,6 +38,9 @@
 #include <common/compat/prctl.h>
 #include <common/unix.h>
 #include <common/defaults.h>
+#include <common/lttng-elf.h>
+
+#include <lttng/constant.h>
 
 #include "runas.h"
 
@@ -64,6 +67,10 @@ struct run_as_rmdir_recursive_data {
        char path[PATH_MAX];
 };
 
+struct run_as_extract_elf_symbol_offset_data {
+       char function[LTTNG_SYMBOL_NAME_LEN];
+};
+
 struct run_as_mkdir_ret {
        int ret;
 };
@@ -80,12 +87,17 @@ struct run_as_rmdir_recursive_ret {
        int ret;
 };
 
+struct run_as_extract_elf_symbol_offset_ret {
+       uint64_t offset;
+};
+
 enum run_as_cmd {
        RUN_AS_MKDIR,
        RUN_AS_OPEN,
        RUN_AS_UNLINK,
        RUN_AS_RMDIR_RECURSIVE,
        RUN_AS_MKDIR_RECURSIVE,
+       RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET,
 };
 
 struct run_as_data {
@@ -96,6 +108,7 @@ struct run_as_data {
                struct run_as_open_data open;
                struct run_as_unlink_data unlink;
                struct run_as_rmdir_recursive_data rmdir_recursive;
+               struct run_as_extract_elf_symbol_offset_data extract_elf_symbol_offset;
        } u;
        uid_t uid;
        gid_t gid;
@@ -123,6 +136,7 @@ struct run_as_ret {
                struct run_as_open_ret open;
                struct run_as_unlink_ret unlink;
                struct run_as_rmdir_recursive_ret rmdir_recursive;
+               struct run_as_extract_elf_symbol_offset_ret extract_elf_symbol_offset;
        } u;
        int _errno;
        bool _error;
@@ -212,6 +226,25 @@ int _rmdir_recursive(struct run_as_data *data, struct run_as_ret *ret_value)
        return ret_value->u.rmdir_recursive.ret;
 }
 
+static
+int _extract_elf_symbol_offset(struct run_as_data *data,
+               struct run_as_ret *ret_value)
+{
+       int ret = 0;
+       ret_value->_error = false;
+
+       ret = lttng_elf_get_symbol_offset(data->fd,
+                        data->u.extract_elf_symbol_offset.function,
+                        &ret_value->u.extract_elf_symbol_offset.offset);
+       if (ret) {
+               DBG("Failed to extract ELF function offset");
+               ret_value->_error = true;
+       }
+
+       return ret;
+}
+
+
 static
 run_as_fct run_as_enum_to_fct(enum run_as_cmd cmd)
 {
@@ -226,6 +259,8 @@ run_as_fct run_as_enum_to_fct(enum run_as_cmd cmd)
                return _rmdir_recursive;
        case RUN_AS_MKDIR_RECURSIVE:
                return _mkdir_recursive;
+       case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET:
+               return _extract_elf_symbol_offset;
        default:
                ERR("Unknown command %d", (int) cmd);
                return NULL;
@@ -277,6 +312,8 @@ int send_fd_to_worker(struct run_as_worker *worker, enum run_as_cmd cmd, int fd)
        int ret = 0;
 
        switch (cmd) {
+       case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET:
+               break;
        default:
                return 0;
        }
@@ -343,6 +380,8 @@ int recv_fd_from_master(struct run_as_worker *worker, enum run_as_cmd cmd, int *
        int ret = 0;
 
        switch (cmd) {
+       case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET:
+               break;
        default:
                return 0;
        }
@@ -362,6 +401,8 @@ int cleanup_received_fd(enum run_as_cmd cmd, int fd)
        int ret = 0;
 
        switch (cmd) {
+       case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET:
+               break;
        default:
                return 0;
        }
@@ -806,6 +847,34 @@ int run_as_rmdir_recursive(const char *path, uid_t uid, gid_t gid)
        return ret.u.rmdir_recursive.ret;
 }
 
+LTTNG_HIDDEN
+int run_as_extract_elf_symbol_offset(int fd, const char* function,
+               uid_t uid, gid_t gid, uint64_t *offset)
+{
+       struct run_as_data data;
+       struct run_as_ret ret;
+
+       DBG3("extract_elf_symbol_offset() on fd=%d and function=%s "
+               "with for uid %d and gid %d", fd, function, (int) uid, (int) gid);
+
+       data.fd = fd;
+
+       strncpy(data.u.extract_elf_symbol_offset.function, function, LTTNG_SYMBOL_NAME_LEN - 1);
+
+       data.u.extract_elf_symbol_offset.function[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
+
+       run_as(RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET, &data, &ret, uid, gid);
+
+       errno = ret._errno;
+
+       if (ret._error) {
+               return -1;
+       }
+
+       *offset = ret.u.extract_elf_symbol_offset.offset;
+       return 0;
+}
+
 static
 int reset_sighandler(void)
 {