lttng-tools: musl compile fixes

Add two patches to address three distinct build problems spotted by our
build bots when compiling lttng-tools:

1) unconditional use of `__GLIBC_PREREQ`

On musl based toolchains there is no such macro defined, leading to the
following preprocessor error:

      CC       compat-epoll.lo
    In file included from compat-epoll.c:33:0:
    poll.h:76:19: error: missing binary operator before token "("
     #if __GLIBC_PREREQ(2, 9)

2) undeclared `mode_t` type

On musl based toolchains the `mode_t` type is not implicitely defined through
other includes, leading to the following compile error:

      CC       hashtable.lo
    In file included from ../../../src/common/common.h:24:0,
                     from hashtable.c:24:
    ../../../src/common/runas.h:25:46: error: unknown type name 'mode_t'
     int run_as_mkdir_recursive(const char *path, mode_t mode, uid_t uid, gid_t gid);
                                                  ^
    ../../../src/common/runas.h:26:36: error: unknown type name 'mode_t'
     int run_as_mkdir(const char *path, mode_t mode, uid_t uid, gid_t gid);
                                        ^
    ../../../src/common/runas.h:27:46: error: unknown type name 'mode_t'
     int run_as_open(const char *path, int flags, mode_t mode, uid_t uid, gid_t gid);
                                                  ^

3) multiple definitions

The header files declare several `const char *` pointers which are initialized
in various `*.c` files later on. Due to a missing `extern` declaration in the
header, the final linking of the executables fails with errors such as:

      CCLD     lttng
    ../../../src/common/.libs/libcommon.a(mi-lttng.o):(.data.rel.ro.local+0x0): multiple definition of `mi_lttng_element_snapshots'
    commands/enable_events.o:(.bss+0x18): first defined here
    collect2: error: ld returned 1 exit status

This commits addresses these issues with two patches, `100-musl-compat.patch`
fixes issue 1 by declaring a fallback dummy declaration of `__GLIBC_PREREQ` and
issue 2 by explicitely including `sys/stat.h` which provides `mode_t` according
to POSIX.

The second patch, `200-use-extern.patch` declares all char pointers in the
header file as `extern`, fixing the observed linker errors.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

devel/lttng-tools/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=lttng-tools
 PKG_VERSION:=2.6.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=https://lttng.org/files/$(PKG_NAME)/

devel/lttng-tools/patches/100-musl-compat.patch

@@ -0,0 +1,23 @@
+--- a/src/common/compat/poll.h
++++ b/src/common/compat/poll.h
+@@ -55,6 +55,10 @@ static inline void __lttng_poll_free(voi
+ #include <features.h>
+ #include <common/compat/fcntl.h>
+ 
++#ifndef __GLIBC_PREREQ
++#define __GLIBC_PREREQ(maj, min) (0)
++#endif
++
+ /* See man epoll(7) for this define path */
+ #define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
+ 
+--- a/src/common/runas.h
++++ b/src/common/runas.h
+@@ -21,6 +21,7 @@
+ 
+ #include <unistd.h>
+ #include <pthread.h>
++#include <sys/stat.h>
+ 
+ int run_as_mkdir_recursive(const char *path, mode_t mode, uid_t uid, gid_t gid);
+ int run_as_mkdir(const char *path, mode_t mode, uid_t uid, gid_t gid);

devel/lttng-tools/patches/200-use-extern.patch

@@ -0,0 +1,423 @@
+--- a/src/common/mi-lttng.h
++++ b/src/common/mi-lttng.h
+@@ -49,133 +49,133 @@ struct mi_lttng_version {
+ };
+ 
+ /* Strings related to command */
+-const char * const mi_lttng_element_command;
+-const char * const mi_lttng_element_command_action;
+-const char * const mi_lttng_element_command_add_context;
+-const char * const mi_lttng_element_command_calibrate;
+-const char * const mi_lttng_element_command_create;
+-const char * const mi_lttng_element_command_destroy;
+-const char * const mi_lttng_element_command_disable_channel;
+-const char * const mi_lttng_element_command_disable_event;
+-const char * const mi_lttng_element_command_enable_channels;
+-const char * const mi_lttng_element_command_enable_event;
+-const char * const mi_lttng_element_command_list;
+-const char * const mi_lttng_element_command_load;
+-const char * const mi_lttng_element_command_name;
+-const char * const mi_lttng_element_command_output;
+-const char * const mi_lttng_element_command_save;
+-const char * const mi_lttng_element_command_set_session;
+-const char * const mi_lttng_element_command_snapshot;
+-const char * const mi_lttng_element_command_snapshot_add;
+-const char * const mi_lttng_element_command_snapshot_del;
+-const char * const mi_lttng_element_command_snapshot_list;
+-const char * const mi_lttng_element_command_snapshot_record;
+-const char * const mi_lttng_element_command_start;
+-const char * const mi_lttng_element_command_stop;
+-const char * const mi_lttng_element_command_success;
+-const char * const mi_lttng_element_command_version;
++extern const char * const mi_lttng_element_command;
++extern const char * const mi_lttng_element_command_action;
++extern const char * const mi_lttng_element_command_add_context;
++extern const char * const mi_lttng_element_command_calibrate;
++extern const char * const mi_lttng_element_command_create;
++extern const char * const mi_lttng_element_command_destroy;
++extern const char * const mi_lttng_element_command_disable_channel;
++extern const char * const mi_lttng_element_command_disable_event;
++extern const char * const mi_lttng_element_command_enable_channels;
++extern const char * const mi_lttng_element_command_enable_event;
++extern const char * const mi_lttng_element_command_list;
++extern const char * const mi_lttng_element_command_load;
++extern const char * const mi_lttng_element_command_name;
++extern const char * const mi_lttng_element_command_output;
++extern const char * const mi_lttng_element_command_save;
++extern const char * const mi_lttng_element_command_set_session;
++extern const char * const mi_lttng_element_command_snapshot;
++extern const char * const mi_lttng_element_command_snapshot_add;
++extern const char * const mi_lttng_element_command_snapshot_del;
++extern const char * const mi_lttng_element_command_snapshot_list;
++extern const char * const mi_lttng_element_command_snapshot_record;
++extern const char * const mi_lttng_element_command_start;
++extern const char * const mi_lttng_element_command_stop;
++extern const char * const mi_lttng_element_command_success;
++extern const char * const mi_lttng_element_command_version;
+ 
+ /* Strings related to version command */
+-const char * const mi_lttng_element_version;
+-const char * const mi_lttng_element_version_commit;
+-const char * const mi_lttng_element_version_description;
+-const char * const mi_lttng_element_version_license;
+-const char * const mi_lttng_element_version_major;
+-const char * const mi_lttng_element_version_minor;
+-const char * const mi_lttng_element_version_patch_level;
+-const char * const mi_lttng_element_version_str;
+-const char * const mi_lttng_element_version_web;
++extern const char * const mi_lttng_element_version;
++extern const char * const mi_lttng_element_version_commit;
++extern const char * const mi_lttng_element_version_description;
++extern const char * const mi_lttng_element_version_license;
++extern const char * const mi_lttng_element_version_major;
++extern const char * const mi_lttng_element_version_minor;
++extern const char * const mi_lttng_element_version_patch_level;
++extern const char * const mi_lttng_element_version_str;
++extern const char * const mi_lttng_element_version_web;
+ 
+ /* String related to a lttng_event_field */
+-const char * const mi_lttng_element_event_field;
+-const char * const mi_lttng_element_event_fields;
++extern const char * const mi_lttng_element_event_field;
++extern const char * const mi_lttng_element_event_fields;
+ 
+ /* String related to lttng_event_context */
+-const char * const mi_lttng_context_type_perf_counter;
+-const char * const mi_lttng_context_type_perf_cpu_counter;
+-const char * const mi_lttng_context_type_perf_thread_counter;
++extern const char * const mi_lttng_context_type_perf_counter;
++extern const char * const mi_lttng_context_type_perf_cpu_counter;
++extern const char * const mi_lttng_context_type_perf_thread_counter;
+ 
+ /* String related to lttng_event_perf_counter_ctx */
+-const char * const mi_lttng_element_perf_counter_context;
++extern const char * const mi_lttng_element_perf_counter_context;
+ 
+ /* Strings related to pid */
+-const char * const mi_lttng_element_pids;
+-const char * const mi_lttng_element_pid;
+-const char * const mi_lttng_element_pid_id;
++extern const char * const mi_lttng_element_pids;
++extern const char * const mi_lttng_element_pid;
++extern const char * const mi_lttng_element_pid_id;
+ 
+ /* Strings related to save command */
+-const char * const mi_lttng_element_save;
++extern const char * const mi_lttng_element_save;
+ 
+ /* Strings related to load command */
+-const char * const mi_lttng_element_load;
++extern const char * const mi_lttng_element_load;
+ 
+ /* General element of mi_lttng */
+-const char * const mi_lttng_element_empty;
+-const char * const mi_lttng_element_id;
+-const char * const mi_lttng_element_nowrite;
+-const char * const mi_lttng_element_success;
+-const char * const mi_lttng_element_type_enum;
+-const char * const mi_lttng_element_type_float;
+-const char * const mi_lttng_element_type_integer;
+-const char * const mi_lttng_element_type_other;
+-const char * const mi_lttng_element_type_string;
++extern const char * const mi_lttng_element_empty;
++extern const char * const mi_lttng_element_id;
++extern const char * const mi_lttng_element_nowrite;
++extern const char * const mi_lttng_element_success;
++extern const char * const mi_lttng_element_type_enum;
++extern const char * const mi_lttng_element_type_float;
++extern const char * const mi_lttng_element_type_integer;
++extern const char * const mi_lttng_element_type_other;
++extern const char * const mi_lttng_element_type_string;
+ 
+ /* String related to loglevel */
+-const char * const mi_lttng_loglevel_str_alert;
+-const char * const mi_lttng_loglevel_str_crit;
+-const char * const mi_lttng_loglevel_str_debug;
+-const char * const mi_lttng_loglevel_str_debug_function;
+-const char * const mi_lttng_loglevel_str_debug_line;
+-const char * const mi_lttng_loglevel_str_debug_module;
+-const char * const mi_lttng_loglevel_str_debug_process;
+-const char * const mi_lttng_loglevel_str_debug_program;
+-const char * const mi_lttng_loglevel_str_debug_system;
+-const char * const mi_lttng_loglevel_str_debug_unit;
+-const char * const mi_lttng_loglevel_str_emerg;
+-const char * const mi_lttng_loglevel_str_err;
+-const char * const mi_lttng_loglevel_str_info;
+-const char * const mi_lttng_loglevel_str_notice;
+-const char * const mi_lttng_loglevel_str_unknown;
+-const char * const mi_lttng_loglevel_str_warning;
++extern const char * const mi_lttng_loglevel_str_alert;
++extern const char * const mi_lttng_loglevel_str_crit;
++extern const char * const mi_lttng_loglevel_str_debug;
++extern const char * const mi_lttng_loglevel_str_debug_function;
++extern const char * const mi_lttng_loglevel_str_debug_line;
++extern const char * const mi_lttng_loglevel_str_debug_module;
++extern const char * const mi_lttng_loglevel_str_debug_process;
++extern const char * const mi_lttng_loglevel_str_debug_program;
++extern const char * const mi_lttng_loglevel_str_debug_system;
++extern const char * const mi_lttng_loglevel_str_debug_unit;
++extern const char * const mi_lttng_loglevel_str_emerg;
++extern const char * const mi_lttng_loglevel_str_err;
++extern const char * const mi_lttng_loglevel_str_info;
++extern const char * const mi_lttng_loglevel_str_notice;
++extern const char * const mi_lttng_loglevel_str_unknown;
++extern const char * const mi_lttng_loglevel_str_warning;
+ 
+ /* String related to loglevel JUL */
+-const char * const mi_lttng_loglevel_str_jul_all;
+-const char * const mi_lttng_loglevel_str_jul_config;
+-const char * const mi_lttng_loglevel_str_jul_fine;
+-const char * const mi_lttng_loglevel_str_jul_finer;
+-const char * const mi_lttng_loglevel_str_jul_finest;
+-const char * const mi_lttng_loglevel_str_jul_info;
+-const char * const mi_lttng_loglevel_str_jul_off;
+-const char * const mi_lttng_loglevel_str_jul_severe;
+-const char * const mi_lttng_loglevel_str_jul_warning;
++extern const char * const mi_lttng_loglevel_str_jul_all;
++extern const char * const mi_lttng_loglevel_str_jul_config;
++extern const char * const mi_lttng_loglevel_str_jul_fine;
++extern const char * const mi_lttng_loglevel_str_jul_finer;
++extern const char * const mi_lttng_loglevel_str_jul_finest;
++extern const char * const mi_lttng_loglevel_str_jul_info;
++extern const char * const mi_lttng_loglevel_str_jul_off;
++extern const char * const mi_lttng_loglevel_str_jul_severe;
++extern const char * const mi_lttng_loglevel_str_jul_warning;
+ 
+ /* String related to loglevel Log4j */
+-const char * const mi_lttng_loglevel_str_log4j_off;
+-const char * const mi_lttng_loglevel_str_log4j_fatal;
+-const char * const mi_lttng_loglevel_str_log4j_error;
+-const char * const mi_lttng_loglevel_str_log4j_warn;
+-const char * const mi_lttng_loglevel_str_log4j_info;
+-const char * const mi_lttng_loglevel_str_log4j_debug;
+-const char * const mi_lttng_loglevel_str_log4j_trace;
+-const char * const mi_lttng_loglevel_str_log4j_all;
++extern const char * const mi_lttng_loglevel_str_log4j_off;
++extern const char * const mi_lttng_loglevel_str_log4j_fatal;
++extern const char * const mi_lttng_loglevel_str_log4j_error;
++extern const char * const mi_lttng_loglevel_str_log4j_warn;
++extern const char * const mi_lttng_loglevel_str_log4j_info;
++extern const char * const mi_lttng_loglevel_str_log4j_debug;
++extern const char * const mi_lttng_loglevel_str_log4j_trace;
++extern const char * const mi_lttng_loglevel_str_log4j_all;
+ 
+ /* String related to loglevel type */
+-const char * const mi_lttng_loglevel_type_all;
+-const char * const mi_lttng_loglevel_type_range;
+-const char * const mi_lttng_loglevel_type_single;
+-const char * const mi_lttng_loglevel_type_unknown;
++extern const char * const mi_lttng_loglevel_type_all;
++extern const char * const mi_lttng_loglevel_type_range;
++extern const char * const mi_lttng_loglevel_type_single;
++extern const char * const mi_lttng_loglevel_type_unknown;
+ 
+ /* Sting related to lttng_calibrate */
+-const char * const mi_lttng_element_calibrate;
+-const char * const mi_lttng_element_calibrate_function;
++extern const char * const mi_lttng_element_calibrate;
++extern const char * const mi_lttng_element_calibrate_function;
+ 
+ /* String related to a lttng_snapshot */
+-const char * const mi_lttng_element_snapshot_ctrl_url;
+-const char * const mi_lttng_element_snapshot_data_url;
+-const char * const mi_lttng_element_snapshot_max_size;
+-const char * const mi_lttng_element_snapshot_n_ptr;
+-const char * const mi_lttng_element_snapshot_session_name;
+-const char * const mi_lttng_element_snapshots;
++extern const char * const mi_lttng_element_snapshot_ctrl_url;
++extern const char * const mi_lttng_element_snapshot_data_url;
++extern const char * const mi_lttng_element_snapshot_max_size;
++extern const char * const mi_lttng_element_snapshot_n_ptr;
++extern const char * const mi_lttng_element_snapshot_session_name;
++extern const char * const mi_lttng_element_snapshots;
+ 
+ /* Utility string function  */
+ const char *mi_lttng_loglevel_string(int value, enum lttng_domain_type domain);
+--- a/src/common/config/config-session-abi.h
++++ b/src/common/config/config-session-abi.h
+@@ -18,95 +18,95 @@
+ #ifndef CONFIG_SESSION_INTERNAL_H
+ #define CONFIG_SESSION_INTERNAL_H
+ 
+-const char * const config_element_channel;
+-const char * const config_element_channels;
+-const char * const config_element_domain;
+-const char * const config_element_domains;
+-const char * const config_element_event;
+-const char * const config_element_events;
+-const char * const config_element_context;
+-const char * const config_element_contexts;
+-const char * const config_element_attributes;
+-const char * const config_element_exclusion;
+-const char * const config_element_exclusions;
+-const char * const config_element_function_attributes;
+-const char * const config_element_probe_attributes;
+-const char * const config_element_symbol_name;
+-const char * const config_element_address;
+-const char * const config_element_offset;
+-const char * const config_element_name;
+-const char * const config_element_enabled;
+-const char * const config_element_overwrite_mode;
+-const char * const config_element_subbuf_size;
+-const char * const config_element_num_subbuf;
+-const char * const config_element_switch_timer_interval;
+-const char * const config_element_read_timer_interval;
+-const char * const config_element_output;
+-const char * const config_element_output_type;
+-const char * const config_element_tracefile_size;
+-const char * const config_element_tracefile_count;
+-const char * const config_element_live_timer_interval;
+-const char * const config_element_type;
+-const char * const config_element_buffer_type;
+-const char * const config_element_session;
+-const char * const config_element_sessions;
+-const char * const config_element_perf;
+-const char * const config_element_config;
+-const char * const config_element_started;
+-const char * const config_element_snapshot_mode;
+-const char * const config_element_loglevel;
+-const char * const config_element_loglevel_type;
+-const char * const config_element_filter;
+-const char * const config_element_snapshot_outputs;
+-const char * const config_element_consumer_output;
+-const char * const config_element_destination;
+-const char * const config_element_path;
+-const char * const config_element_net_output;
+-const char * const config_element_control_uri;
+-const char * const config_element_data_uri;
+-const char * const config_element_max_size;
+-
+-const char * const config_domain_type_kernel;
+-const char * const config_domain_type_ust;
+-const char * const config_domain_type_jul;
+-const char * const config_domain_type_log4j;
+-
+-const char * const config_buffer_type_per_pid;
+-const char * const config_buffer_type_per_uid;
+-const char * const config_buffer_type_global;
+-
+-const char * const config_overwrite_mode_discard;
+-const char * const config_overwrite_mode_overwrite;
+-
+-const char * const config_output_type_splice;
+-const char * const config_output_type_mmap;
+-
+-const char * const config_loglevel_type_all;
+-const char * const config_loglevel_type_range;
+-const char * const config_loglevel_type_single;
+-
+-const char * const config_event_type_all;
+-const char * const config_event_type_tracepoint;
+-const char * const config_event_type_probe;
+-const char * const config_event_type_function;
+-const char * const config_event_type_function_entry;
+-const char * const config_event_type_noop;
+-const char * const config_event_type_syscall;
+-const char * const config_event_type_kprobe;
+-const char * const config_event_type_kretprobe;
+-
+-const char * const config_event_context_pid;
+-const char * const config_event_context_procname;
+-const char * const config_event_context_prio;
+-const char * const config_event_context_nice;
+-const char * const config_event_context_vpid;
+-const char * const config_event_context_tid;
+-const char * const config_event_context_vtid;
+-const char * const config_event_context_ppid;
+-const char * const config_event_context_vppid;
+-const char * const config_event_context_pthread_id;
+-const char * const config_event_context_hostname;
+-const char * const config_event_context_ip;
+-const char * const config_event_context_perf_thread_counter;
++extern const char * const config_element_channel;
++extern const char * const config_element_channels;
++extern const char * const config_element_domain;
++extern const char * const config_element_domains;
++extern const char * const config_element_event;
++extern const char * const config_element_events;
++extern const char * const config_element_context;
++extern const char * const config_element_contexts;
++extern const char * const config_element_attributes;
++extern const char * const config_element_exclusion;
++extern const char * const config_element_exclusions;
++extern const char * const config_element_function_attributes;
++extern const char * const config_element_probe_attributes;
++extern const char * const config_element_symbol_name;
++extern const char * const config_element_address;
++extern const char * const config_element_offset;
++extern const char * const config_element_name;
++extern const char * const config_element_enabled;
++extern const char * const config_element_overwrite_mode;
++extern const char * const config_element_subbuf_size;
++extern const char * const config_element_num_subbuf;
++extern const char * const config_element_switch_timer_interval;
++extern const char * const config_element_read_timer_interval;
++extern const char * const config_element_output;
++extern const char * const config_element_output_type;
++extern const char * const config_element_tracefile_size;
++extern const char * const config_element_tracefile_count;
++extern const char * const config_element_live_timer_interval;
++extern const char * const config_element_type;
++extern const char * const config_element_buffer_type;
++extern const char * const config_element_session;
++extern const char * const config_element_sessions;
++extern const char * const config_element_perf;
++extern const char * const config_element_config;
++extern const char * const config_element_started;
++extern const char * const config_element_snapshot_mode;
++extern const char * const config_element_loglevel;
++extern const char * const config_element_loglevel_type;
++extern const char * const config_element_filter;
++extern const char * const config_element_snapshot_outputs;
++extern const char * const config_element_consumer_output;
++extern const char * const config_element_destination;
++extern const char * const config_element_path;
++extern const char * const config_element_net_output;
++extern const char * const config_element_control_uri;
++extern const char * const config_element_data_uri;
++extern const char * const config_element_max_size;
++
++extern const char * const config_domain_type_kernel;
++extern const char * const config_domain_type_ust;
++extern const char * const config_domain_type_jul;
++extern const char * const config_domain_type_log4j;
++
++extern const char * const config_buffer_type_per_pid;
++extern const char * const config_buffer_type_per_uid;
++extern const char * const config_buffer_type_global;
++
++extern const char * const config_overwrite_mode_discard;
++extern const char * const config_overwrite_mode_overwrite;
++
++extern const char * const config_output_type_splice;
++extern const char * const config_output_type_mmap;
++
++extern const char * const config_loglevel_type_all;
++extern const char * const config_loglevel_type_range;
++extern const char * const config_loglevel_type_single;
++
++extern const char * const config_event_type_all;
++extern const char * const config_event_type_tracepoint;
++extern const char * const config_event_type_probe;
++extern const char * const config_event_type_function;
++extern const char * const config_event_type_function_entry;
++extern const char * const config_event_type_noop;
++extern const char * const config_event_type_syscall;
++extern const char * const config_event_type_kprobe;
++extern const char * const config_event_type_kretprobe;
++
++extern const char * const config_event_context_pid;
++extern const char * const config_event_context_procname;
++extern const char * const config_event_context_prio;
++extern const char * const config_event_context_nice;
++extern const char * const config_event_context_vpid;
++extern const char * const config_event_context_tid;
++extern const char * const config_event_context_vtid;
++extern const char * const config_event_context_ppid;
++extern const char * const config_event_context_vppid;
++extern const char * const config_event_context_pthread_id;
++extern const char * const config_event_context_hostname;
++extern const char * const config_event_context_ip;
++extern const char * const config_event_context_perf_thread_counter;
+ 
+ #endif /* CONFIG_SESSION_INTERNAL_H */