servers/vfs/coredump.c

   1 #include "fs.h"
   2 #include <fcntl.h>
   3 #include <string.h>
   4 #include "fproc.h"
   5 #include <minix/vm.h>
   6 #include <sys/mman.h>
   7 #include <sys/exec_elf.h>
   8 #include "param.h"
   9
  10 /* Include ELF headers */
  11 #include <sys/elf_core.h>
  12 #include <machine/elf.h>
  13
  14 static void fill_elf_header(Elf32_Ehdr *elf_header, int phnum);
  15 static void fill_prog_header(Elf32_Phdr *prog_header, Elf32_Word
  16         p_type, Elf32_Off p_offset, Elf32_Addr p_vaddr, Elf32_Word p_flags,
  17         Elf32_Word p_filesz, Elf32_Word p_memsz);
  18 static int get_memory_regions(Elf32_Phdr phdrs[]);
  19 static void fill_note_segment_and_entries_hdrs(Elf32_Phdr phdrs[],
  20         Elf32_Nhdr nhdrs[]);
  21 static void adjust_offsets(Elf32_Phdr phdrs[], int phnum);
  22 static void dump_elf_header(struct filp *f, Elf32_Ehdr elf_header);
  23 static void dump_notes(struct filp *f, Elf32_Nhdr nhdrs[], int csig,
  24         char *proc_name);
  25 static void dump_program_headers(struct filp *f, Elf_Phdr phdrs[], int
  26         phnum);
  27 static void dump_segments(struct filp *f, Elf32_Phdr phdrs[], int
  28         phnum);
  29 static void write_buf(struct filp *f, char *buf, size_t size);
  30
  31 /*===========================================================================*
  32  *                              write_elf_core_file                          *
  33  *===========================================================================*/
  34 void write_elf_core_file(struct filp *f, int csig, char *proc_name)
  35 {
  36 /* First, fill in all the required headers, second, adjust the offsets,
  37  * third, dump everything into the core file
  38  */
  39 #define MAX_REGIONS 100
  40 #define NR_NOTE_ENTRIES 2
  41   Elf_Ehdr elf_header;
  42   Elf_Phdr phdrs[MAX_REGIONS + 1];
  43   Elf_Nhdr nhdrs[NR_NOTE_ENTRIES];
  44   int phnum;
  45
  46   memset(phdrs, 0, sizeof(phdrs));
  47
  48   /* Fill in the NOTE Program Header - at phdrs[0] - and
  49    * note entries' headers
  50    */
  51   fill_note_segment_and_entries_hdrs(phdrs, nhdrs);
  52
  53   /* Get the memory segments and fill in the Program headers */
  54   phnum = get_memory_regions(phdrs) + 1;
  55
  56   /* Fill in the ELF header */
  57   fill_elf_header(&elf_header, phnum);
  58
  59   /* Adjust offsets in program headers - The layout in the ELF core file
  60    * is the following: the ELF Header, the Note Program Header,
  61    * the rest of Program Headers (memory segments), Note contents,
  62    * the program segments' contents
  63    */
  64   adjust_offsets(phdrs, phnum);
  65
  66   /* Write ELF header */
  67   dump_elf_header(f, elf_header);
  68
  69   /* Write Program headers (Including the NOTE) */
  70   dump_program_headers(f, phdrs, phnum);
  71
  72   /* Write NOTE contents */
  73   dump_notes(f, nhdrs, csig, proc_name);
  74
  75   /* Write segments' contents */
  76   dump_segments(f, phdrs, phnum);
  77 }
  78
  79 /*===========================================================================*
  80  *                              fill_elf_header                              *
  81  *===========================================================================*/
  82 static void fill_elf_header (Elf_Ehdr *elf_header, int phnum)
  83 {
  84   memset((void *) elf_header, 0, sizeof(Elf_Ehdr));
  85
  86   elf_header->e_ident[EI_MAG0] = ELFMAG0;
  87   elf_header->e_ident[EI_MAG1] = ELFMAG1;
  88   elf_header->e_ident[EI_MAG2] = ELFMAG2;
  89   elf_header->e_ident[EI_MAG3] = ELFMAG3;
  90   elf_header->e_ident[EI_CLASS] = ELF_TARG_CLASS;
  91   elf_header->e_ident[EI_DATA] = ELF_TARG_DATA;
  92   elf_header->e_ident[EI_VERSION] = EV_CURRENT;
  93   elf_header->e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
  94   elf_header->e_type = ET_CORE;
  95   elf_header->e_machine = ELF_TARG_MACH;
  96   elf_header->e_version = EV_CURRENT;
  97   elf_header->e_ehsize = sizeof(Elf_Ehdr);
  98   elf_header->e_phoff = sizeof(Elf_Ehdr);
  99   elf_header->e_phentsize = sizeof(Elf_Phdr);
 100   elf_header->e_phnum = phnum;
 101 }
 102
 103 /*===========================================================================*
 104  *                              fill_prog_header                             *
 105  *===========================================================================*/
 106 static void fill_prog_header (Elf_Phdr *prog_header, Elf_Word p_type,
 107         Elf_Off p_offset, Elf_Addr p_vaddr, Elf_Word p_flags,
 108         Elf_Word p_filesz, Elf_Word p_memsz)
 109 {
 110
 111   memset((void *) prog_header, 0, sizeof(Elf_Phdr));
 112
 113   prog_header->p_type = p_type;
 114   prog_header->p_offset = p_offset;
 115   prog_header->p_vaddr = p_vaddr;
 116   prog_header->p_flags = p_flags;
 117   prog_header->p_filesz = p_filesz;
 118   prog_header->p_memsz = p_memsz;
 119
 120 }
 121
 122 #define PADBYTES    4
 123 #define PAD_LEN(x)  ((x + (PADBYTES - 1)) & ~(PADBYTES - 1))
 124
 125 /*===========================================================================*
 126  *                      fill_note_segment_and_entries_hdrs                   *
 127  *===========================================================================*/
 128 static void fill_note_segment_and_entries_hdrs(Elf_Phdr phdrs[],
 129                                 Elf_Nhdr nhdrs[])
 130 {
 131   int filesize;
 132   const char *note_name = ELF_NOTE_MINIX_ELFCORE_NAME "\0";
 133   int name_len, mei_len, gregs_len;
 134
 135   /* Size of notes in the core file is rather fixed:
 136    * sizeof(minix_elfcore_info_t) +
 137    * 2 * sizeof(Elf_Nhdr) + the size of the padded name of the note
 138    * - i.e. "MINIX-CORE\0" padded to 4-byte alignment => 2 * 8 bytes
 139    */
 140
 141   name_len = strlen(note_name) + 1;
 142   mei_len = sizeof(minix_elfcore_info_t);
 143   gregs_len = sizeof(gregset_t);
 144
 145   /* Make sure to also count the padding bytes */
 146   filesize = PAD_LEN(mei_len) + PAD_LEN(gregs_len) +
 147         2 * sizeof(Elf_Nhdr) + 2 * PAD_LEN(name_len);
 148   fill_prog_header(&phdrs[0], PT_NOTE, 0, 0, PF_R, filesize, 0);
 149
 150   /* First note entry header */
 151   nhdrs[0].n_namesz = name_len;
 152   nhdrs[0].n_descsz = sizeof(minix_elfcore_info_t);
 153   nhdrs[0].n_type = NT_MINIX_ELFCORE_INFO;
 154
 155   /* Second note entry header */
 156   nhdrs[1].n_namesz = name_len;
 157   nhdrs[1].n_descsz = sizeof(gregset_t);
 158   nhdrs[1].n_type = NT_MINIX_ELFCORE_GREGS;
 159 }
 160
 161 /*===========================================================================*
 162  *                              adjust_offset                                *
 163  *===========================================================================*/
 164 static void adjust_offsets(Elf_Phdr phdrs[], int phnum)
 165 {
 166   int i;
 167   long offset = sizeof(Elf_Ehdr) + phnum * sizeof(Elf_Phdr);
 168
 169   for (i = 0; i < phnum; i++) {
 170         phdrs[i].p_offset = offset;
 171         offset += phdrs[i].p_filesz;
 172   }
 173 }
 174
 175 /*===========================================================================*
 176  *                              write_buf                                    *
 177  *===========================================================================*/
 178 static void write_buf(struct filp *f, char *buf, size_t size)
 179 {
 180   read_write(WRITING, f, buf, size, VFS_PROC_NR);
 181 }
 182
 183 /*===========================================================================*
 184  *                              get_memory_regions                           *
 185  *===========================================================================*/
 186 static int get_memory_regions(Elf_Phdr phdrs[])
 187 {
 188   /* Print the virtual memory regions of a process. */
 189
 190   /* The same as dump_regions from procfs/pid.c */
 191   struct vm_region_info vri[MAX_VRI_COUNT];
 192   vir_bytes next;
 193   int i, r, count;
 194   Elf_Word pflags;
 195
 196   count = 0;
 197   next = 0;
 198
 199   do {
 200         r = vm_info_region(fp->fp_endpoint, vri, MAX_VRI_COUNT, &next);
 201         if (r < 0) return r;
 202         if (r == 0) break;
 203
 204         for (i = 0; i < r; i++) {
 205                 pflags =  (vri[i].vri_prot & PROT_READ ? PF_R : 0)
 206                         | (vri[i].vri_prot & PROT_WRITE ? PF_W : 0)
 207                         | (vri[i].vri_prot & PROT_EXEC ? PF_X : 0);
 208
 209                 fill_prog_header (&phdrs[count + 1], PT_LOAD,
 210                                 0, vri[i].vri_addr, pflags,
 211                                 vri[i].vri_length, vri[i].vri_length);
 212                 count++;
 213
 214                 if (count >= MAX_REGIONS) {
 215                         printf("VFS: get_memory_regions Warning: "
 216                                 "Program has too many regions\n");
 217                         return(count);
 218                 }
 219         }
 220   } while (r == MAX_VRI_COUNT);
 221
 222   return(count);
 223 }
 224
 225 /*===========================================================================*
 226  *                              dump_notes                                   *
 227  *===========================================================================*/
 228 static void dump_notes(struct filp *f, Elf_Nhdr nhdrs[], int csig,
 229                          char *proc_name)
 230 {
 231   char *note_name = ELF_NOTE_MINIX_ELFCORE_NAME "\0";
 232   char pad[4];
 233   minix_elfcore_info_t mei;
 234   int mei_len = sizeof(minix_elfcore_info_t);
 235   int gregs_len = sizeof(gregset_t);
 236   struct stackframe_s regs;
 237
 238   /* Dump first note entry */
 239   mei.mei_version = MINIX_ELFCORE_VERSION;
 240   mei.mei_meisize = mei_len;
 241   mei.mei_signo = csig;
 242   mei.mei_pid = fp->fp_pid;
 243   memcpy(mei.mei_command, proc_name, sizeof(mei.mei_command));
 244
 245   write_buf(f, (char *) &nhdrs[0], sizeof(Elf_Nhdr));
 246   write_buf(f, note_name, nhdrs[0].n_namesz);
 247   write_buf(f, pad, PAD_LEN(nhdrs[0].n_namesz) - nhdrs[0].n_namesz);
 248   write_buf(f, (char *) &mei, mei_len);
 249   write_buf(f, pad, PAD_LEN(mei_len) - mei_len);
 250
 251   /* Get registers */
 252   if (sys_getregs(&regs, fp->fp_endpoint) != OK)
 253         printf("VFS: Could not read registers\n");
 254
 255   if (sizeof(regs) != gregs_len)
 256         printf("VFS: Wrong core register structure size\n");
 257
 258   /* Dump second note entry - the general registers */
 259   write_buf(f, (char *) &nhdrs[1], sizeof(Elf_Nhdr));
 260
 261   write_buf(f, note_name, nhdrs[1].n_namesz);
 262   write_buf(f, pad, PAD_LEN(nhdrs[1].n_namesz) - nhdrs[1].n_namesz);
 263   write_buf(f, (char *) &regs, gregs_len);
 264   write_buf(f, pad, PAD_LEN(gregs_len) - gregs_len);
 265 }
 266
 267 /*===========================================================================*
 268  *                              dump_elf_header                              *
 269  *===========================================================================*/
 270 static void dump_elf_header(struct filp *f, Elf_Ehdr elf_header)
 271 {
 272   write_buf(f, (char *) &elf_header, sizeof(Elf_Ehdr));
 273 }
 274
 275 /*===========================================================================*
 276  *                        dump_program_headers                               *
 277  *===========================================================================*/
 278 static void dump_program_headers(struct filp *f, Elf_Phdr phdrs[], int phnum)
 279 {
 280   int i;
 281
 282   for (i = 0; i < phnum; i++)
 283         write_buf(f, (char *) &phdrs[i], sizeof(Elf_Phdr));
 284 }
 285
 286 /*===========================================================================*
 287  *                            dump_segments                                  *
 288  *===========================================================================*/
 289 static void dump_segments(struct filp *f, Elf_Phdr phdrs[], int phnum)
 290 {
 291   int i;
 292   vir_bytes len;
 293   off_t off, seg_off;
 294   int r;
 295   static u8_t buf[CLICK_SIZE];
 296
 297   for (i = 1; i < phnum; i++) {
 298         len = phdrs[i].p_memsz;
 299         seg_off = phdrs[i].p_vaddr;
 300
 301         if (len > LONG_MAX) {
 302                 printf("VFS: segment too large to dump, truncating\n");
 303                 len = LONG_MAX;
 304         }
 305
 306         for (off = 0; off < (off_t) len; off += CLICK_SIZE) {
 307                 vir_bytes p = (vir_bytes) (seg_off + off);
 308                 r = sys_vircopy(fp->fp_endpoint, p,
 309                         SELF, (vir_bytes) buf,
 310                         (phys_bytes) CLICK_SIZE);
 311
 312                 if(r != OK) {
 313                         printf("VFS: vircopy failed for %d @ 0x%lx during coredump\n",
 314                                 fp->fp_endpoint, p);
 315                         break;
 316                 }
 317
 318                 write_buf(f, (char *) buf, (off + CLICK_SIZE <= (off_t) len) ?
 319                                         CLICK_SIZE : (len - off));
 320         }
 321   }
 322 }