diff --git a/std/c/linux.zig b/std/c/linux.zig index 1f7139965b..48e359f361 100644 --- a/std/c/linux.zig +++ b/std/c/linux.zig @@ -1,3 +1,4 @@ +const linux = @import("../os/linux.zig"); pub use @import("../os/linux/errno.zig"); pub extern "c" fn getrandom(buf_ptr: [*]u8, buf_len: usize, flags: c_uint) c_int; @@ -12,4 +13,5 @@ pub const pthread_attr_t = extern struct { /// See std.elf for constants for this pub extern fn getauxval(__type: c_ulong) c_ulong; -pub extern fn dl_iterate_phdr(callback: *const c_void, data: ?*c_void) i32; +pub const dl_iterate_phdr_callback = extern fn (info: *linux.dl_phdr_info, size: usize, data: ?*c_void) c_int; +pub extern fn dl_iterate_phdr(callback: dl_iterate_phdr_callback, data: ?*c_void) c_int; diff --git a/std/dynamic_library.zig b/std/dynamic_library.zig index c116a8de53..b2064311db 100644 --- a/std/dynamic_library.zig +++ b/std/dynamic_library.zig @@ -19,25 +19,29 @@ pub const DynLib = switch (builtin.os) { else => void, }; +// The link_map structure is not completely specified beside the fields +// reported below, any libc is free to store additional data in the remaining +// space. +// An iterator is provided in order to traverse the linked list in a idiomatic +// fashion. const LinkMap = extern struct { l_addr: usize, - l_name: [*]u8, - l_ld: [*c]elf.Dyn, - l_next: [*c]LinkMap, - l_prev: [*c]LinkMap, + l_name: [*]const u8, + l_ld: ?*elf.Dyn, + l_next: ?*LinkMap, + l_prev: ?*LinkMap, pub const Iterator = struct { - lm_ptr: [*c]LinkMap, + current: ?*LinkMap, - fn end(self: *const Iterator) bool { - return self.lm_ptr == 0; + fn end(self: *Iterator) bool { + return self.current == null; } fn next(self: *Iterator) ?*LinkMap { - if (self.lm_ptr != 0) { - const ptr = self.lm_ptr; - self.lm_ptr = self.lm_ptr.*.l_next; - return ptr; + if (self.current) |it| { + self.current = it.l_next; + return it; } return null; } @@ -46,7 +50,7 @@ const LinkMap = extern struct { const RDebug = extern struct { r_version: i32, - r_map: [*c]LinkMap, + r_map: ?*LinkMap, r_brk: usize, r_ldbase: usize, }; @@ -72,7 +76,7 @@ pub fn linkmap_iterator(phdrs: []elf.Phdr) !LinkMap.Iterator { } // No PT_DYNAMIC means this is either a statically-linked program or a // badly corrupted one - return LinkMap.Iterator{.lm_ptr = 0}; + return LinkMap.Iterator{.current = null}; }; const link_map_ptr = init: { @@ -87,7 +91,7 @@ pub fn linkmap_iterator(phdrs: []elf.Phdr) !LinkMap.Iterator { const got_table = @intToPtr([*]usize, dyn.d_un.d_ptr); // The address to the link_map structure is stored in the // second slot - break :init @intToPtr([*c]LinkMap, got_table[1]); + break :init @intToPtr(?*LinkMap, got_table[1]); }, else => { } } @@ -95,7 +99,7 @@ pub fn linkmap_iterator(phdrs: []elf.Phdr) !LinkMap.Iterator { return error.InvalidExe; }; - return LinkMap.Iterator{.lm_ptr = link_map_ptr}; + return LinkMap.Iterator{.current = link_map_ptr}; } pub const LinuxDynLib = struct { diff --git a/std/os/linux.zig b/std/os/linux.zig index 1dae263ede..739342df60 100644 --- a/std/os/linux.zig +++ b/std/os/linux.zig @@ -4,6 +4,7 @@ const builtin = @import("builtin"); const maxInt = std.math.maxInt; const elf = std.elf; const vdso = @import("linux/vdso.zig"); +const dl = @import("../dynamic_library.zig"); pub use switch (builtin.arch) { builtin.Arch.x86_64 => @import("linux/x86_64.zig"), builtin.Arch.i386 => @import("linux/i386.zig"), @@ -1537,33 +1538,32 @@ pub const dirent64 = extern struct { pub const dl_phdr_info = extern struct { dlpi_addr: usize, - dlpi_name: [*c]const u8, - dlpi_phdr: [*c]*c_void, + dlpi_name: ?[*]const u8, + dlpi_phdr: [*]elf.Phdr, dlpi_phnum: u16, }; -const DynLib = @import("../dynamic_library.zig"); - // XXX: This should be weak extern const __ehdr_start: elf.Ehdr = undefined; -pub fn dl_iterate_phdr(callback: extern fn (info: *dl_phdr_info, size: usize, data: ?*c_void) i32, data: ?*c_void) isize { +pub fn dl_iterate_phdr(comptime T: type, callback: extern fn (info: *dl_phdr_info, size: usize, data: ?*T) i32, data: ?*T) isize { if (builtin.link_libc) { - return std.c.dl_iterate_phdr(@ptrCast(*const c_void, callback), data); + return std.c.dl_iterate_phdr(@ptrCast(std.c.dl_iterate_phdr_callback, callback), @ptrCast(?*c_void, data)); } const elf_base = @ptrToInt(&__ehdr_start); const n_phdr = __ehdr_start.e_phnum; const phdrs = (@intToPtr([*]elf.Phdr, elf_base + __ehdr_start.e_phoff))[0..n_phdr]; - var it = DynLib.linkmap_iterator(phdrs) catch return 0; + var it = dl.linkmap_iterator(phdrs) catch return 0; + + // The executable has no dynamic link segment, create a single entry for + // the whole ELF image if (it.end()) { - // The executable has no dynamic link infos, create a single info - // struct for the whole ELF image var info = dl_phdr_info{ .dlpi_addr = elf_base, .dlpi_name = c"/proc/self/exe", - .dlpi_phdr = @intToPtr([*c]*c_void, elf_base + __ehdr_start.e_phoff), + .dlpi_phdr = @intToPtr([*]elf.Phdr, elf_base + __ehdr_start.e_phoff), .dlpi_phnum = __ehdr_start.e_phnum, }; @@ -1573,23 +1573,26 @@ pub fn dl_iterate_phdr(callback: extern fn (info: *dl_phdr_info, size: usize, da // Last return value from the callback function var last_r: isize = 0; while (it.next()) |entry| { - var info = dl_phdr_info{ - .dlpi_addr = entry.l_addr, - .dlpi_name = entry.l_name, - .dlpi_phdr = 0, - .dlpi_phnum = 0, - }; + var dlpi_phdr: usize = undefined; + var dlpi_phnum: u16 = undefined; if (entry.l_addr != 0) { const elf_header = @intToPtr(*elf.Ehdr, entry.l_addr); - info.dlpi_phdr = @intToPtr([*c]*c_void, entry.l_addr + elf_header.e_phoff); - info.dlpi_phnum = elf_header.e_phnum; + dlpi_phdr = entry.l_addr + elf_header.e_phoff; + dlpi_phnum = elf_header.e_phnum; } else { // This is the running ELF image - info.dlpi_phdr = @intToPtr([*c]*c_void, elf_base + __ehdr_start.e_phoff); - info.dlpi_phnum = __ehdr_start.e_phnum; + dlpi_phdr = elf_base + __ehdr_start.e_phoff; + dlpi_phnum = __ehdr_start.e_phnum; } + var info = dl_phdr_info{ + .dlpi_addr = entry.l_addr, + .dlpi_name = entry.l_name, + .dlpi_phdr = @intToPtr([*]elf.Phdr, dlpi_phdr), + .dlpi_phnum = dlpi_phnum, + }; + last_r = callback(&info, @sizeOf(dl_phdr_info), data); if (last_r != 0) break; }