[444] | 1 | #include <elf.h>
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| 2 | #include <limits.h>
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| 3 | #include <sys/mman.h>
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| 4 | #include <string.h>
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| 5 | #include <stddef.h>
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| 6 | #include "pthread_impl.h"
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| 7 | #include "libc.h"
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| 8 | #include "atomic.h"
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| 9 | #include "syscall.h"
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| 10 |
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| 11 | int __init_tp(void *p)
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| 12 | {
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| 13 | pthread_t td = p;
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| 14 | td->self = td;
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| 15 | int r = __set_thread_area(TP_ADJ(p));
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| 16 | if (r < 0) return -1;
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| 17 | if (!r) libc.can_do_threads = 1;
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| 18 | td->tid = __syscall(SYS_set_tid_address, &td->tid);
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| 19 | td->locale = &libc.global_locale;
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| 20 | td->robust_list.head = &td->robust_list.head;
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| 21 | return 0;
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| 22 | }
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| 23 |
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| 24 | static struct builtin_tls {
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| 25 | char c;
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| 26 | struct pthread pt;
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| 27 | void *space[16];
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| 28 | } builtin_tls[1];
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| 29 | #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
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| 30 |
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| 31 | static struct tls_module main_tls;
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| 32 |
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| 33 | void *__copy_tls(unsigned char *mem)
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| 34 | {
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| 35 | pthread_t td;
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| 36 | struct tls_module *p;
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| 37 | size_t i;
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| 38 | void **dtv;
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| 39 |
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| 40 | #ifdef TLS_ABOVE_TP
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| 41 | dtv = (void **)(mem + libc.tls_size) - (libc.tls_cnt + 1);
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| 42 |
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| 43 | mem += -((uintptr_t)mem + sizeof(struct pthread)) & (libc.tls_align-1);
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| 44 | td = (pthread_t)mem;
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| 45 | mem += sizeof(struct pthread);
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| 46 |
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| 47 | for (i=1, p=libc.tls_head; p; i++, p=p->next) {
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| 48 | dtv[i] = mem + p->offset;
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| 49 | memcpy(dtv[i], p->image, p->len);
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| 50 | }
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| 51 | #else
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| 52 | dtv = (void **)mem;
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| 53 |
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| 54 | mem += libc.tls_size - sizeof(struct pthread);
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| 55 | mem -= (uintptr_t)mem & (libc.tls_align-1);
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| 56 | td = (pthread_t)mem;
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| 57 |
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| 58 | for (i=1, p=libc.tls_head; p; i++, p=p->next) {
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| 59 | dtv[i] = mem - p->offset;
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| 60 | memcpy(dtv[i], p->image, p->len);
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| 61 | }
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| 62 | #endif
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| 63 | dtv[0] = (void *)libc.tls_cnt;
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| 64 | td->dtv = td->dtv_copy = dtv;
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| 65 | return td;
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| 66 | }
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| 67 |
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| 68 | #if ULONG_MAX == 0xffffffff
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| 69 | typedef Elf32_Phdr Phdr;
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| 70 | #else
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| 71 | typedef Elf64_Phdr Phdr;
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| 72 | #endif
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| 73 |
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| 74 | __attribute__((__weak__, __visibility__("hidden")))
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| 75 | extern const size_t _DYNAMIC[];
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| 76 |
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| 77 | static void static_init_tls(size_t *aux)
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| 78 | {
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| 79 | unsigned char *p;
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| 80 | size_t n;
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| 81 | Phdr *phdr, *tls_phdr=0;
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| 82 | size_t base = 0;
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| 83 | void *mem;
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| 84 |
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| 85 | for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
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| 86 | phdr = (void *)p;
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| 87 | if (phdr->p_type == PT_PHDR)
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| 88 | base = aux[AT_PHDR] - phdr->p_vaddr;
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| 89 | if (phdr->p_type == PT_DYNAMIC && _DYNAMIC)
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| 90 | base = (size_t)_DYNAMIC - phdr->p_vaddr;
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| 91 | if (phdr->p_type == PT_TLS)
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| 92 | tls_phdr = phdr;
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| 93 | }
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| 94 |
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| 95 | if (tls_phdr) {
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| 96 | main_tls.image = (void *)(base + tls_phdr->p_vaddr);
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| 97 | main_tls.len = tls_phdr->p_filesz;
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| 98 | main_tls.size = tls_phdr->p_memsz;
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| 99 | main_tls.align = tls_phdr->p_align;
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| 100 | libc.tls_cnt = 1;
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| 101 | libc.tls_head = &main_tls;
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| 102 | }
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| 103 |
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| 104 | main_tls.size += (-main_tls.size - (uintptr_t)main_tls.image)
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| 105 | & (main_tls.align-1);
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| 106 | if (main_tls.align < MIN_TLS_ALIGN) main_tls.align = MIN_TLS_ALIGN;
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| 107 | #ifndef TLS_ABOVE_TP
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| 108 | main_tls.offset = main_tls.size;
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| 109 | #endif
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| 110 |
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| 111 | libc.tls_align = main_tls.align;
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| 112 | libc.tls_size = 2*sizeof(void *) + sizeof(struct pthread)
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| 113 | + main_tls.size + main_tls.align
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| 114 | + MIN_TLS_ALIGN-1 & -MIN_TLS_ALIGN;
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| 115 |
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| 116 | if (libc.tls_size > sizeof builtin_tls) {
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| 117 | #ifndef SYS_mmap2
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| 118 | #define SYS_mmap2 SYS_mmap
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| 119 | #endif
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| 120 | mem = (void *)__syscall(
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| 121 | SYS_mmap2,
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| 122 | 0, libc.tls_size, PROT_READ|PROT_WRITE,
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| 123 | MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
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| 124 | /* -4095...-1 cast to void * will crash on dereference anyway,
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| 125 | * so don't bloat the init code checking for error codes and
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| 126 | * explicitly calling a_crash(). */
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| 127 | } else {
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| 128 | mem = builtin_tls;
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| 129 | }
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| 130 |
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| 131 | /* Failure to initialize thread pointer is always fatal. */
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| 132 | if (__init_tp(__copy_tls(mem)) < 0)
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| 133 | a_crash();
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| 134 | }
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| 135 |
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| 136 | weak_alias(static_init_tls, __init_tls);
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