Auto merge of #3125 - workingjubilee:joy/unified-auxvec.rs, r=JohnTitor

Unify **/uapi/linux/auxvec.h in linux_like/mod.rs

The NDK automatically generates this from Linux kernel headers. It seems best to simply unify these, since where the kernel goes, Android will undoubtedly follow. Also, note relevant versions.

New in this patch: `AT_MINSIGSTKSZ`

This const is needed to handle new extensions to platform arches that add state to save to signal stacks, replacing `MINSIGSTKSZ` with an ELF-loaded equivalent.

Author: bors

libc-test/semver/linux.txt

@@ -167,6 +167,7 @@ AT_GID
 AT_HWCAP
 AT_HWCAP2
 AT_IGNORE
+AT_MINSIGSTKSZ
 AT_NOTELF
 AT_NO_AUTOMOUNT
 AT_NULL

src/unix/linux_like/android/b64/mod.rs

@@ -264,31 +264,6 @@ pub const RTLD_GLOBAL: ::c_int = 0x00100;
 pub const RTLD_NOW: ::c_int = 2;
 pub const RTLD_DEFAULT: *mut ::c_void = 0i64 as *mut ::c_void;
 
-// From NDK's linux/auxvec.h
-pub const AT_NULL: ::c_ulong = 0;
-pub const AT_IGNORE: ::c_ulong = 1;
-pub const AT_EXECFD: ::c_ulong = 2;
-pub const AT_PHDR: ::c_ulong = 3;
-pub const AT_PHENT: ::c_ulong = 4;
-pub const AT_PHNUM: ::c_ulong = 5;
-pub const AT_PAGESZ: ::c_ulong = 6;
-pub const AT_BASE: ::c_ulong = 7;
-pub const AT_FLAGS: ::c_ulong = 8;
-pub const AT_ENTRY: ::c_ulong = 9;
-pub const AT_NOTELF: ::c_ulong = 10;
-pub const AT_UID: ::c_ulong = 11;
-pub const AT_EUID: ::c_ulong = 12;
-pub const AT_GID: ::c_ulong = 13;
-pub const AT_EGID: ::c_ulong = 14;
-pub const AT_PLATFORM: ::c_ulong = 15;
-pub const AT_HWCAP: ::c_ulong = 16;
-pub const AT_CLKTCK: ::c_ulong = 17;
-pub const AT_SECURE: ::c_ulong = 23;
-pub const AT_BASE_PLATFORM: ::c_ulong = 24;
-pub const AT_RANDOM: ::c_ulong = 25;
-pub const AT_HWCAP2: ::c_ulong = 26;
-pub const AT_EXECFN: ::c_ulong = 31;
-
 pub const PTHREAD_MUTEX_INITIALIZER: pthread_mutex_t = pthread_mutex_t {
     value: 0,
     __reserved: [0; 36],

src/unix/linux_like/linux/mod.rs

@@ -1638,37 +1638,6 @@ pub const PF_R: u32 = 1 << 2;
 pub const PF_MASKOS: u32 = 0x0ff00000;
 pub const PF_MASKPROC: u32 = 0xf0000000;
 
-// elf.h - Legal values for a_type (entry type).
-pub const AT_NULL: ::c_ulong = 0;
-pub const AT_IGNORE: ::c_ulong = 1;
-pub const AT_EXECFD: ::c_ulong = 2;
-pub const AT_PHDR: ::c_ulong = 3;
-pub const AT_PHENT: ::c_ulong = 4;
-pub const AT_PHNUM: ::c_ulong = 5;
-pub const AT_PAGESZ: ::c_ulong = 6;
-pub const AT_BASE: ::c_ulong = 7;
-pub const AT_FLAGS: ::c_ulong = 8;
-pub const AT_ENTRY: ::c_ulong = 9;
-pub const AT_NOTELF: ::c_ulong = 10;
-pub const AT_UID: ::c_ulong = 11;
-pub const AT_EUID: ::c_ulong = 12;
-pub const AT_GID: ::c_ulong = 13;
-pub const AT_EGID: ::c_ulong = 14;
-pub const AT_PLATFORM: ::c_ulong = 15;
-pub const AT_HWCAP: ::c_ulong = 16;
-pub const AT_CLKTCK: ::c_ulong = 17;
-
-pub const AT_SECURE: ::c_ulong = 23;
-pub const AT_BASE_PLATFORM: ::c_ulong = 24;
-pub const AT_RANDOM: ::c_ulong = 25;
-pub const AT_HWCAP2: ::c_ulong = 26;
-
-pub const AT_EXECFN: ::c_ulong = 31;
-
-// defined in arch/<arch>/include/uapi/asm/auxvec.h but has the same value
-// wherever it is defined.
-pub const AT_SYSINFO_EHDR: ::c_ulong = 33;
-
 pub const GLOB_ERR: ::c_int = 1 << 0;
 pub const GLOB_MARK: ::c_int = 1 << 1;
 pub const GLOB_NOSORT: ::c_int = 1 << 2;

src/unix/linux_like/mod.rs

@@ -1196,13 +1196,53 @@ pub const POSIX_FADV_RANDOM: ::c_int = 1;
 pub const POSIX_FADV_SEQUENTIAL: ::c_int = 2;
 pub const POSIX_FADV_WILLNEED: ::c_int = 3;
 
-pub const AT_FDCWD: ::c_int = -100;
-pub const AT_SYMLINK_NOFOLLOW: ::c_int = 0x100;
-pub const AT_REMOVEDIR: ::c_int = 0x200;
-pub const AT_SYMLINK_FOLLOW: ::c_int = 0x400;
-pub const AT_NO_AUTOMOUNT: ::c_int = 0x800;
-pub const AT_EMPTY_PATH: ::c_int = 0x1000;
-pub const AT_RECURSIVE: ::c_int = 0x8000;
+// flags for "at"-suffixed file operations, e.g. execveat, openat
+pub const AT_FDCWD: ::c_int = -100; // used instead of dirfd
+pub const AT_REMOVEDIR: ::c_int = 0x200; // unlinkat
+pub const AT_SYMLINK_NOFOLLOW: ::c_int = 0x100; // fstatat
+pub const AT_NO_AUTOMOUNT: ::c_int = 0x800; // fstatat
+pub const AT_SYMLINK_FOLLOW: ::c_int = 0x400; // linkat
+pub const AT_EMPTY_PATH: ::c_int = 0x1000; // linkat
+pub const AT_RECURSIVE: ::c_int = 0x8000; // mount_setattr
+
+// not to be confused with this completely unrelated list:
+// keys to the values in the ELF auxiliary vector, usable with getauxval
+// found at uapi/linux/auxvec.h in the kernel and elf/elf.h in musl and glibc
+pub const AT_NULL: ::c_ulong = 0;
+pub const AT_IGNORE: ::c_ulong = 1;
+pub const AT_EXECFD: ::c_ulong = 2;
+pub const AT_PHDR: ::c_ulong = 3;
+pub const AT_PHENT: ::c_ulong = 4;
+pub const AT_PHNUM: ::c_ulong = 5;
+pub const AT_PAGESZ: ::c_ulong = 6;
+pub const AT_BASE: ::c_ulong = 7;
+pub const AT_FLAGS: ::c_ulong = 8;
+pub const AT_ENTRY: ::c_ulong = 9;
+pub const AT_NOTELF: ::c_ulong = 10;
+pub const AT_UID: ::c_ulong = 11;
+pub const AT_EUID: ::c_ulong = 12;
+pub const AT_GID: ::c_ulong = 13;
+pub const AT_EGID: ::c_ulong = 14;
+pub const AT_PLATFORM: ::c_ulong = 15;
+pub const AT_HWCAP: ::c_ulong = 16;
+pub const AT_CLKTCK: ::c_ulong = 17;
+
+pub const AT_SECURE: ::c_ulong = 23;
+pub const AT_BASE_PLATFORM: ::c_ulong = 24;
+pub const AT_RANDOM: ::c_ulong = 25;
+pub const AT_HWCAP2: ::c_ulong = 26;
+
+pub const AT_EXECFN: ::c_ulong = 31;
+
+// defined in arch/<arch>/include/uapi/asm/auxvec.h but has the same value
+// wherever it is defined, so glibc and musl also define it universally
+// unsupported values return ENOENT so it's relatively "safe" to define
+pub const AT_SYSINFO_EHDR: ::c_ulong = 33;
+
+pub const AT_MINSIGSTKSZ: ::c_ulong = 51;
+// getauxval AT_* values should be current for all "architecture-neutral" ones as of
+// Linux headers: include/uapi/linux/auxvec.h    kernel 6.1
+// Android NDK: libc/kernel/uapi/linux/auxvec.h  NDK 25 (updated ~5.14)
 
 pub const LOG_CRON: ::c_int = 9 << 3;
 pub const LOG_AUTHPRIV: ::c_int = 10 << 3;