| 1 | /* This test program is part of GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 2011-2020 Free Software Foundation, Inc. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation; either version 3 of the License, or |
| 8 | (at your option) any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | /* Simulate loading of JIT code. */ |
| 19 | |
| 20 | #include <elf.h> |
| 21 | #include <link.h> |
| 22 | #include <errno.h> |
| 23 | #include <fcntl.h> |
| 24 | #include <stdint.h> |
| 25 | #include <stdio.h> |
| 26 | #include <stdlib.h> |
| 27 | #include <string.h> |
| 28 | #include <sys/mman.h> |
| 29 | #include <sys/stat.h> |
| 30 | #include <unistd.h> |
| 31 | |
| 32 | /* ElfW is coming from linux. On other platforms it does not exist. |
| 33 | Let us define it here. */ |
| 34 | #ifndef ElfW |
| 35 | # if (defined (_LP64) || defined (__LP64__)) |
| 36 | # define WORDSIZE 64 |
| 37 | # else |
| 38 | # define WORDSIZE 32 |
| 39 | # endif /* _LP64 || __LP64__ */ |
| 40 | #define ElfW(type) _ElfW (Elf, WORDSIZE, type) |
| 41 | #define _ElfW(e,w,t) _ElfW_1 (e, w, _##t) |
| 42 | #define _ElfW_1(e,w,t) e##w##t |
| 43 | #endif /* !ElfW */ |
| 44 | |
| 45 | typedef enum |
| 46 | { |
| 47 | JIT_NOACTION = 0, |
| 48 | JIT_REGISTER_FN, |
| 49 | JIT_UNREGISTER_FN |
| 50 | } jit_actions_t; |
| 51 | |
| 52 | struct jit_code_entry |
| 53 | { |
| 54 | struct jit_code_entry *next_entry; |
| 55 | struct jit_code_entry *prev_entry; |
| 56 | const char *symfile_addr; |
| 57 | uint64_t symfile_size; |
| 58 | }; |
| 59 | |
| 60 | struct jit_descriptor |
| 61 | { |
| 62 | uint32_t version; |
| 63 | /* This type should be jit_actions_t, but we use uint32_t |
| 64 | to be explicit about the bitwidth. */ |
| 65 | uint32_t action_flag; |
| 66 | struct jit_code_entry *relevant_entry; |
| 67 | struct jit_code_entry *first_entry; |
| 68 | }; |
| 69 | |
| 70 | /* GDB puts a breakpoint in this function. */ |
| 71 | void __attribute__((noinline)) __jit_debug_register_code () { } |
| 72 | |
| 73 | /* Make sure to specify the version statically, because the |
| 74 | debugger may check the version before we can set it. */ |
| 75 | struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 }; |
| 76 | |
| 77 | static void |
| 78 | usage (const char *const argv0) |
| 79 | { |
| 80 | fprintf (stderr, "Usage: %s library [count]\n", argv0); |
| 81 | exit (1); |
| 82 | } |
| 83 | |
| 84 | /* Update .p_vaddr and .sh_addr as if the code was JITted to ADDR. */ |
| 85 | |
| 86 | static void |
| 87 | update_locations (const void *const addr, int idx) |
| 88 | { |
| 89 | const ElfW (Ehdr) *const ehdr = (ElfW (Ehdr) *)addr; |
| 90 | ElfW (Shdr) *const shdr = (ElfW (Shdr) *)((char *)addr + ehdr->e_shoff); |
| 91 | ElfW (Phdr) *const phdr = (ElfW (Phdr) *)((char *)addr + ehdr->e_phoff); |
| 92 | int i; |
| 93 | |
| 94 | for (i = 0; i < ehdr->e_phnum; ++i) |
| 95 | if (phdr[i].p_type == PT_LOAD) |
| 96 | phdr[i].p_vaddr += (ElfW (Addr))addr; |
| 97 | |
| 98 | for (i = 0; i < ehdr->e_shnum; ++i) |
| 99 | { |
| 100 | if (shdr[i].sh_type == SHT_STRTAB) |
| 101 | { |
| 102 | /* Note: we update both .strtab and .dynstr. The latter would |
| 103 | not be correct if this were a regular shared library (.hash |
| 104 | would be wrong), but this is a simulation -- the library is |
| 105 | never exposed to the dynamic loader, so it all ends up ok. */ |
| 106 | char *const strtab = (char *)((ElfW (Addr))addr + shdr[i].sh_offset); |
| 107 | char *const strtab_end = strtab + shdr[i].sh_size; |
| 108 | char *p; |
| 109 | |
| 110 | for (p = strtab; p < strtab_end; p += strlen (p) + 1) |
| 111 | if (strcmp (p, "jit_function_XXXX") == 0) |
| 112 | sprintf (p, "jit_function_%04d", idx); |
| 113 | } |
| 114 | |
| 115 | if (shdr[i].sh_flags & SHF_ALLOC) |
| 116 | shdr[i].sh_addr += (ElfW (Addr))addr; |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | /* Defined by the .exp file if testing attach. */ |
| 121 | #ifndef ATTACH |
| 122 | #define ATTACH 0 |
| 123 | #endif |
| 124 | |
| 125 | #ifndef MAIN |
| 126 | #define MAIN main |
| 127 | #endif |
| 128 | |
| 129 | /* Used to spin waiting for GDB. */ |
| 130 | volatile int wait_for_gdb = ATTACH; |
| 131 | #define WAIT_FOR_GDB while (wait_for_gdb) |
| 132 | |
| 133 | /* The current process's PID. GDB retrieves this. */ |
| 134 | int mypid; |
| 135 | |
| 136 | int |
| 137 | MAIN (int argc, char *argv[]) |
| 138 | { |
| 139 | /* These variables are here so they can easily be set from jit.exp. */ |
| 140 | const char *libname = NULL; |
| 141 | int count = 0, i, fd; |
| 142 | struct stat st; |
| 143 | |
| 144 | alarm (300); |
| 145 | |
| 146 | mypid = getpid (); |
| 147 | |
| 148 | count = count; /* gdb break here 0 */ |
| 149 | |
| 150 | if (argc < 2) |
| 151 | { |
| 152 | usage (argv[0]); |
| 153 | exit (1); |
| 154 | } |
| 155 | |
| 156 | if (libname == NULL) |
| 157 | /* Only set if not already set from GDB. */ |
| 158 | libname = argv[1]; |
| 159 | |
| 160 | if (argc > 2 && count == 0) |
| 161 | /* Only set if not already set from GDB. */ |
| 162 | count = atoi (argv[2]); |
| 163 | |
| 164 | printf ("%s:%d: libname = %s, count = %d\n", __FILE__, __LINE__, |
| 165 | libname, count); |
| 166 | |
| 167 | if ((fd = open (libname, O_RDONLY)) == -1) |
| 168 | { |
| 169 | fprintf (stderr, "open (\"%s\", O_RDONLY): %s\n", libname, |
| 170 | strerror (errno)); |
| 171 | exit (1); |
| 172 | } |
| 173 | |
| 174 | if (fstat (fd, &st) != 0) |
| 175 | { |
| 176 | fprintf (stderr, "fstat (\"%d\"): %s\n", fd, strerror (errno)); |
| 177 | exit (1); |
| 178 | } |
| 179 | |
| 180 | for (i = 0; i < count; ++i) |
| 181 | { |
| 182 | const void *const addr = mmap (0, st.st_size, PROT_READ|PROT_WRITE, |
| 183 | MAP_PRIVATE, fd, 0); |
| 184 | struct jit_code_entry *const entry = calloc (1, sizeof (*entry)); |
| 185 | |
| 186 | if (addr == MAP_FAILED) |
| 187 | { |
| 188 | fprintf (stderr, "mmap: %s\n", strerror (errno)); |
| 189 | exit (1); |
| 190 | } |
| 191 | |
| 192 | update_locations (addr, i); |
| 193 | |
| 194 | /* Link entry at the end of the list. */ |
| 195 | entry->symfile_addr = (const char *)addr; |
| 196 | entry->symfile_size = st.st_size; |
| 197 | entry->prev_entry = __jit_debug_descriptor.relevant_entry; |
| 198 | __jit_debug_descriptor.relevant_entry = entry; |
| 199 | |
| 200 | if (entry->prev_entry != NULL) |
| 201 | entry->prev_entry->next_entry = entry; |
| 202 | else |
| 203 | __jit_debug_descriptor.first_entry = entry; |
| 204 | |
| 205 | /* Notify GDB. */ |
| 206 | __jit_debug_descriptor.action_flag = JIT_REGISTER_FN; |
| 207 | __jit_debug_register_code (); |
| 208 | } |
| 209 | |
| 210 | WAIT_FOR_GDB; i = 0; /* gdb break here 1 */ |
| 211 | |
| 212 | /* Now unregister them all in reverse order. */ |
| 213 | while (__jit_debug_descriptor.relevant_entry != NULL) |
| 214 | { |
| 215 | struct jit_code_entry *const entry = |
| 216 | __jit_debug_descriptor.relevant_entry; |
| 217 | struct jit_code_entry *const prev_entry = entry->prev_entry; |
| 218 | |
| 219 | if (prev_entry != NULL) |
| 220 | { |
| 221 | prev_entry->next_entry = NULL; |
| 222 | entry->prev_entry = NULL; |
| 223 | } |
| 224 | else |
| 225 | __jit_debug_descriptor.first_entry = NULL; |
| 226 | |
| 227 | /* Notify GDB. */ |
| 228 | __jit_debug_descriptor.action_flag = JIT_UNREGISTER_FN; |
| 229 | __jit_debug_register_code (); |
| 230 | |
| 231 | __jit_debug_descriptor.relevant_entry = prev_entry; |
| 232 | free (entry); |
| 233 | } |
| 234 | |
| 235 | WAIT_FOR_GDB; return 0; /* gdb break here 2 */ |
| 236 | } |