2 * Copyright (c) 1998 John D. Polstra
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: src/usr.bin/gcore/elfcore.c,v 1.5.2.3 2001/07/11 23:59:11 obrien Exp $
29 #define _KERNEL_STRUCTURES
31 #include <sys/param.h>
33 #include <sys/procfs.h>
34 #include <machine/elf.h>
35 #include <vm/vm_param.h>
38 #include <vm/vm_map.h>
50 * Code for generating ELF core dumps.
53 typedef void (*segment_callback
)(vm_map_entry_t
, void *);
55 /* Closure for cb_put_phdr(). */
57 Elf_Phdr
*phdr
; /* Program header to fill in */
58 Elf_Off offset
; /* Offset of segment in core file */
61 /* Closure for cb_size_segment(). */
63 int count
; /* Count of writable segments. */
64 size_t size
; /* Total size of all writable segments. */
67 static void cb_put_phdr(vm_map_entry_t
, void *);
68 static void cb_size_segment(vm_map_entry_t
, void *);
69 static void each_writable_segment(vm_map_entry_t
, segment_callback
,
71 static void elf_corehdr(int fd
, pid_t
, vm_map_entry_t
, int numsegs
,
72 void *hdr
, size_t hdrsize
);
73 static void elf_puthdr(vm_map_entry_t
, void *, size_t *,
74 const prstatus_t
*, const prfpregset_t
*, const prpsinfo_t
*, int numsegs
);
75 static void elf_putnote(void *dst
, size_t *off
, const char *name
, int type
,
76 const void *desc
, size_t descsz
);
77 static void freemap(vm_map_entry_t
);
78 static void readhdrinfo(pid_t
, prstatus_t
*, prfpregset_t
*, prpsinfo_t
*);
79 static vm_map_entry_t
readmap(pid_t
);
82 * Write an ELF coredump for the given pid to the given fd.
85 elf_coredump(int fd
, pid_t pid
)
88 struct sseg_closure seginfo
;
96 /* Get the program's memory map. */
99 /* Size the program segments. */
102 each_writable_segment(map
, cb_size_segment
, &seginfo
);
105 * Calculate the size of the core file header area by making
106 * a dry run of generating it. Nothing is written, but the
107 * size is calculated.
110 elf_puthdr(map
, NULL
, &hdrsize
, NULL
, NULL
, NULL
, seginfo
.count
);
113 * Allocate memory for building the header, fill it up,
116 hdr
= malloc(hdrsize
);
117 if ((hdr
= malloc(hdrsize
)) == NULL
)
118 errx(1, "out of memory");
119 elf_corehdr(fd
, pid
, map
, seginfo
.count
, hdr
, hdrsize
);
121 /* Write the contents of all of the writable segments. */
122 snprintf(memname
, sizeof memname
, "/proc/%d/mem", pid
);
123 if ((memfd
= open(memname
, O_RDONLY
)) == -1)
124 err(1, "cannot open %s", memname
);
126 php
= (Elf_Phdr
*)((char *)hdr
+ sizeof(Elf_Ehdr
)) + 1;
127 for (i
= 0; i
< seginfo
.count
; i
++) {
128 int nleft
= php
->p_filesz
;
130 lseek(memfd
, (off_t
)php
->p_vaddr
, SEEK_SET
);
137 if (nwant
> sizeof buf
)
139 ngot
= read(memfd
, buf
, nwant
);
141 err(1, "read from %s", memname
);
143 errx(1, "short read from %s:"
144 " wanted %d, got %d\n", memname
,
146 ngot
= write(fd
, buf
, nwant
);
148 err(1, "write of segment %d failed", i
);
150 errx(1, "short write");
161 * A callback for each_writable_segment() to write out the segment's
162 * program header entry.
165 cb_put_phdr(vm_map_entry_t entry
, void *closure
)
167 struct phdr_closure
*phc
= (struct phdr_closure
*)closure
;
168 Elf_Phdr
*phdr
= phc
->phdr
;
170 phc
->offset
= round_page(phc
->offset
);
172 phdr
->p_type
= PT_LOAD
;
173 phdr
->p_offset
= phc
->offset
;
174 phdr
->p_vaddr
= entry
->start
;
176 phdr
->p_filesz
= phdr
->p_memsz
= entry
->end
- entry
->start
;
177 phdr
->p_align
= PAGE_SIZE
;
179 if (entry
->protection
& VM_PROT_READ
)
180 phdr
->p_flags
|= PF_R
;
181 if (entry
->protection
& VM_PROT_WRITE
)
182 phdr
->p_flags
|= PF_W
;
183 if (entry
->protection
& VM_PROT_EXECUTE
)
184 phdr
->p_flags
|= PF_X
;
186 phc
->offset
+= phdr
->p_filesz
;
191 * A callback for each_writable_segment() to gather information about
192 * the number of segments and their total size.
195 cb_size_segment(vm_map_entry_t entry
, void *closure
)
197 struct sseg_closure
*ssc
= (struct sseg_closure
*)closure
;
200 ssc
->size
+= entry
->end
- entry
->start
;
204 * For each segment in the given memory map, call the given function
205 * with a pointer to the map entry and some arbitrary caller-supplied
209 each_writable_segment(vm_map_entry_t map
, segment_callback func
, void *closure
)
211 vm_map_entry_t entry
;
213 for (entry
= map
; entry
!= NULL
; entry
= entry
->next
)
214 (*func
)(entry
, closure
);
218 * Write the core file header to the file, including padding up to
222 elf_corehdr(int fd
, pid_t pid
, vm_map_entry_t map
, int numsegs
, void *hdr
,
227 prfpregset_t fpregset
;
230 /* Gather the information for the header. */
231 readhdrinfo(pid
, &status
, &fpregset
, &psinfo
);
233 /* Fill in the header. */
234 memset(hdr
, 0, hdrsize
);
236 elf_puthdr(map
, hdr
, &off
, &status
, &fpregset
, &psinfo
, numsegs
);
238 /* Write it to the core file. */
239 if (write(fd
, hdr
, hdrsize
) == -1)
244 * Generate the ELF coredump header into the buffer at "dst". "dst" may
245 * be NULL, in which case the header is sized but not actually generated.
248 elf_puthdr(vm_map_entry_t map
, void *dst
, size_t *off
, const prstatus_t
*status
,
249 const prfpregset_t
*fpregset
, const prpsinfo_t
*psinfo
, int numsegs
)
257 *off
+= sizeof(Elf_Ehdr
);
260 *off
+= (numsegs
+ 1) * sizeof(Elf_Phdr
);
263 elf_putnote(dst
, off
, "FreeBSD", NT_PRSTATUS
, status
,
265 elf_putnote(dst
, off
, "FreeBSD", NT_FPREGSET
, fpregset
,
267 elf_putnote(dst
, off
, "FreeBSD", NT_PRPSINFO
, psinfo
,
269 notesz
= *off
- noteoff
;
271 /* Align up to a page boundary for the program segments. */
272 *off
= round_page(*off
);
277 struct phdr_closure phc
;
280 * Fill in the ELF header.
282 ehdr
= (Elf_Ehdr
*)((char *)dst
+ ehoff
);
283 ehdr
->e_ident
[EI_MAG0
] = ELFMAG0
;
284 ehdr
->e_ident
[EI_MAG1
] = ELFMAG1
;
285 ehdr
->e_ident
[EI_MAG2
] = ELFMAG2
;
286 ehdr
->e_ident
[EI_MAG3
] = ELFMAG3
;
287 ehdr
->e_ident
[EI_CLASS
] = ELF_CLASS
;
288 ehdr
->e_ident
[EI_DATA
] = ELF_DATA
;
289 ehdr
->e_ident
[EI_VERSION
] = EV_CURRENT
;
290 ehdr
->e_ident
[EI_OSABI
] = ELFOSABI_NONE
;
291 ehdr
->e_ident
[EI_ABIVERSION
] = 0;
292 ehdr
->e_ident
[EI_PAD
] = 0;
293 ehdr
->e_type
= ET_CORE
;
294 ehdr
->e_machine
= ELF_ARCH
;
295 ehdr
->e_version
= EV_CURRENT
;
297 ehdr
->e_phoff
= phoff
;
299 ehdr
->e_ehsize
= sizeof(Elf_Ehdr
);
300 ehdr
->e_phentsize
= sizeof(Elf_Phdr
);
301 ehdr
->e_phnum
= numsegs
+ 1;
302 ehdr
->e_shentsize
= sizeof(Elf_Shdr
);
304 ehdr
->e_shstrndx
= SHN_UNDEF
;
307 * Fill in the program header entries.
309 phdr
= (Elf_Phdr
*)((char *)dst
+ phoff
);
311 /* The note segement. */
312 phdr
->p_type
= PT_NOTE
;
313 phdr
->p_offset
= noteoff
;
316 phdr
->p_filesz
= notesz
;
322 /* All the writable segments from the program. */
325 each_writable_segment(map
, cb_put_phdr
, &phc
);
330 * Emit one note section to "dst", or just size it if "dst" is NULL.
333 elf_putnote(void *dst
, size_t *off
, const char *name
, int type
,
334 const void *desc
, size_t descsz
)
338 note
.n_namesz
= strlen(name
) + 1;
339 note
.n_descsz
= descsz
;
342 bcopy(¬e
, (char *)dst
+ *off
, sizeof note
);
345 bcopy(name
, (char *)dst
+ *off
, note
.n_namesz
);
346 *off
+= roundup2(note
.n_namesz
, sizeof(Elf_Size
));
348 bcopy(desc
, (char *)dst
+ *off
, note
.n_descsz
);
349 *off
+= roundup2(note
.n_descsz
, sizeof(Elf_Size
));
353 * Free the memory map.
356 freemap(vm_map_entry_t map
)
358 while (map
!= NULL
) {
359 vm_map_entry_t next
= map
->next
;
366 * Read the process information necessary to fill in the core file's header.
369 readhdrinfo(pid_t pid
, prstatus_t
*status
, prfpregset_t
*fpregset
,
378 memset(status
, 0, sizeof *status
);
379 status
->pr_version
= PRSTATUS_VERSION
;
380 status
->pr_statussz
= sizeof(prstatus_t
);
381 status
->pr_gregsetsz
= sizeof(gregset_t
);
382 status
->pr_fpregsetsz
= sizeof(fpregset_t
);
383 status
->pr_osreldate
= __DragonFly_version
;
384 status
->pr_pid
= pid
;
386 memset(fpregset
, 0, sizeof *fpregset
);
388 memset(psinfo
, 0, sizeof *psinfo
);
389 psinfo
->pr_version
= PRPSINFO_VERSION
;
390 psinfo
->pr_psinfosz
= sizeof(prpsinfo_t
);
392 /* Read the general registers. */
393 snprintf(name
, sizeof name
, "/proc/%d/regs", pid
);
394 if ((fd
= open(name
, O_RDONLY
)) == -1)
395 err(1, "cannot open %s", name
);
396 if ((n
= read(fd
, &status
->pr_reg
, sizeof status
->pr_reg
)) == -1)
397 err(1, "read error from %s", name
);
398 if (n
< sizeof status
->pr_reg
)
399 errx(1, "short read from %s: wanted %zu, got %d",
400 name
, sizeof(status
->pr_reg
), n
);
403 /* Read the floating point registers. */
404 snprintf(name
, sizeof name
, "/proc/%d/fpregs", pid
);
405 if ((fd
= open(name
, O_RDONLY
)) == -1)
406 err(1, "cannot open %s", name
);
407 if ((n
= read(fd
, fpregset
, sizeof *fpregset
)) == -1)
408 err(1, "read error from %s", name
);
409 if (n
< sizeof *fpregset
)
410 errx(1, "short read from %s: wanted %zu, got %d",
411 name
, sizeof(*fpregset
), n
);
414 /* Read and parse the process status. */
415 snprintf(name
, sizeof name
, "/proc/%d/status", pid
);
416 if ((fd
= open(name
, O_RDONLY
)) == -1)
417 err(1, "cannot open %s", name
);
418 if ((n
= read(fd
, line
, sizeof line
- 1)) == -1)
419 err(1, "read error from %s", name
);
422 for (i
= 0; i
< n
&& line
[i
] != ' '; i
++)
423 psinfo
->pr_fname
[i
] = line
[i
];
424 strncpy(psinfo
->pr_psargs
, psinfo
->pr_fname
, PRARGSZ
);
429 * Read the process's memory map using procfs, and return a list of
430 * VM map entries. Only the non-device read/writable segments are
431 * returned. The map entries in the list aren't fully filled in; only
432 * the items we need are present.
434 static vm_map_entry_t
444 vm_map_entry_t
*linkp
;
446 snprintf(mapname
, sizeof mapname
, "/proc/%d/map", pid
);
447 if ((mapfd
= open(mapname
, O_RDONLY
)) == -1)
448 err(1, "cannot open %s", mapname
);
451 * Procfs requires (for consistency) that the entire memory map
452 * be read with a single read() call. Start with a reasonbly sized
453 * buffer, and double it until it is big enough.
458 if ((mapbuf
= realloc(mapbuf
, bufsize
+ 1)) == NULL
)
459 errx(1, "out of memory");
460 mapsize
= read(mapfd
, mapbuf
, bufsize
);
461 if (mapsize
!= -1 || errno
!= EFBIG
)
464 /* This lseek shouldn't be necessary, but it is. */
465 lseek(mapfd
, (off_t
)0, SEEK_SET
);
468 err(1, "read error from %s", mapname
);
470 errx(1, "empty map file %s", mapname
);
477 while (pos
< mapsize
) {
487 n
= sscanf(mapbuf
+ pos
, "%lx %lx %*d %*d %*x %3[-rwx]"
488 " %*d %*d %*x %*s %*s %15s %*s%*[\n]%n",
489 &start
, &end
, prot
, type
, &len
);
491 errx(1, "ill-formed line in %s", mapname
);
494 /* Ignore segments of the wrong kind, and unwritable ones */
495 if (strncmp(prot
, "rw", 2) != 0 ||
496 (strcmp(type
, "default") != 0 &&
497 strcmp(type
, "vnode") != 0 &&
498 strcmp(type
, "swap") != 0))
501 if ((ent
= (vm_map_entry_t
)calloc(1, sizeof *ent
)) == NULL
)
502 errx(1, "out of memory");
505 ent
->protection
= VM_PROT_READ
| VM_PROT_WRITE
;
507 ent
->protection
|= VM_PROT_EXECUTE
;