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
29 #include <sys/param.h>
30 #include <sys/procfs.h>
31 #include <machine/elf.h>
32 #include <vm/vm_param.h>
35 #include <vm/vm_map.h>
47 * Code for generating ELF core dumps.
50 typedef void (*segment_callback)(vm_map_entry_t, void *);
52 /* Closure for cb_put_phdr(). */
54 Elf_Phdr *phdr; /* Program header to fill in */
55 Elf_Off offset; /* Offset of segment in core file */
58 /* Closure for cb_size_segment(). */
60 int count; /* Count of writable segments. */
61 size_t size; /* Total size of all writable segments. */
64 static void cb_put_phdr(vm_map_entry_t, void *);
65 static void cb_size_segment(vm_map_entry_t, void *);
66 static void each_writable_segment(vm_map_entry_t, segment_callback,
68 static void elf_corehdr(int fd, pid_t, vm_map_entry_t, int numsegs,
69 void *hdr, size_t hdrsize);
70 static void elf_puthdr(vm_map_entry_t, void *, size_t *,
71 const prstatus_t *, const prfpregset_t *, const prpsinfo_t *, int numsegs);
72 static void elf_putnote(void *dst, size_t *off, const char *name, int type,
73 const void *desc, size_t descsz);
74 static void freemap(vm_map_entry_t);
75 static void readhdrinfo(pid_t, prstatus_t *, prfpregset_t *, prpsinfo_t *);
76 static vm_map_entry_t readmap(pid_t);
79 * Write an ELF coredump for the given pid to the given fd.
82 elf_coredump(int fd, pid_t pid)
85 struct sseg_closure seginfo;
93 /* Get the program's memory map. */
96 /* Size the program segments. */
99 each_writable_segment(map, cb_size_segment, &seginfo);
102 * Calculate the size of the core file header area by making
103 * a dry run of generating it. Nothing is written, but the
104 * size is calculated.
107 elf_puthdr(map, (void *)NULL, &hdrsize,
108 (const prstatus_t *)NULL, (const prfpregset_t *)NULL,
109 (const prpsinfo_t *)NULL, seginfo.count);
112 * Allocate memory for building the header, fill it up,
115 hdr = malloc(hdrsize);
116 if ((hdr = malloc(hdrsize)) == NULL)
117 errx(1, "out of memory");
118 elf_corehdr(fd, pid, map, seginfo.count, hdr, hdrsize);
120 /* Write the contents of all of the writable segments. */
121 snprintf(memname, sizeof memname, "/proc/%d/mem", pid);
122 if ((memfd = open(memname, O_RDONLY)) == -1)
123 err(1, "cannot open %s", memname);
125 php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1;
126 for (i = 0; i < seginfo.count; i++) {
127 int nleft = php->p_filesz;
129 lseek(memfd, (off_t)php->p_vaddr, SEEK_SET);
136 if (nwant > sizeof buf)
138 ngot = read(memfd, buf, nwant);
140 err(1, "read from %s", memname);
142 errx(1, "short read from %s:"
143 " wanted %d, got %d\n", memname,
145 ngot = write(fd, buf, nwant);
147 err(1, "write of segment %d failed", i);
149 errx(1, "short write");
160 * A callback for each_writable_segment() to write out the segment's
161 * program header entry.
164 cb_put_phdr(vm_map_entry_t entry, void *closure)
166 struct phdr_closure *phc = (struct phdr_closure *)closure;
167 Elf_Phdr *phdr = phc->phdr;
169 phc->offset = round_page(phc->offset);
171 phdr->p_type = PT_LOAD;
172 phdr->p_offset = phc->offset;
173 phdr->p_vaddr = entry->start;
175 phdr->p_filesz = phdr->p_memsz = entry->end - entry->start;
176 phdr->p_align = PAGE_SIZE;
178 if (entry->protection & VM_PROT_READ)
179 phdr->p_flags |= PF_R;
180 if (entry->protection & VM_PROT_WRITE)
181 phdr->p_flags |= PF_W;
182 if (entry->protection & VM_PROT_EXECUTE)
183 phdr->p_flags |= PF_X;
185 phc->offset += phdr->p_filesz;
190 * A callback for each_writable_segment() to gather information about
191 * the number of segments and their total size.
194 cb_size_segment(vm_map_entry_t entry, void *closure)
196 struct sseg_closure *ssc = (struct sseg_closure *)closure;
199 ssc->size += entry->end - entry->start;
203 * For each segment in the given memory map, call the given function
204 * with a pointer to the map entry and some arbitrary caller-supplied
208 each_writable_segment(vm_map_entry_t map, segment_callback func, void *closure)
210 vm_map_entry_t entry;
212 for (entry = map; entry != NULL; entry = entry->next)
213 (*func)(entry, closure);
217 * Write the core file header to the file, including padding up to
221 elf_corehdr(int fd, pid_t pid, vm_map_entry_t map, int numsegs, void *hdr,
226 prfpregset_t fpregset;
229 /* Gather the information for the header. */
230 readhdrinfo(pid, &status, &fpregset, &psinfo);
232 /* Fill in the header. */
233 memset(hdr, 0, hdrsize);
235 elf_puthdr(map, hdr, &off, &status, &fpregset, &psinfo, numsegs);
237 /* Write it to the core file. */
238 if (write(fd, hdr, hdrsize) == -1)
243 * Generate the ELF coredump header into the buffer at "dst". "dst" may
244 * be NULL, in which case the header is sized but not actually generated.
247 elf_puthdr(vm_map_entry_t map, void *dst, size_t *off, const prstatus_t *status,
248 const prfpregset_t *fpregset, const prpsinfo_t *psinfo, int numsegs)
256 *off += sizeof(Elf_Ehdr);
259 *off += (numsegs + 1) * sizeof(Elf_Phdr);
262 elf_putnote(dst, off, "FreeBSD", NT_PRSTATUS, status,
264 elf_putnote(dst, off, "FreeBSD", NT_FPREGSET, fpregset,
266 elf_putnote(dst, off, "FreeBSD", NT_PRPSINFO, psinfo,
268 notesz = *off - noteoff;
270 /* Align up to a page boundary for the program segments. */
271 *off = round_page(*off);
276 struct phdr_closure phc;
279 * Fill in the ELF header.
281 ehdr = (Elf_Ehdr *)((char *)dst + ehoff);
282 ehdr->e_ident[EI_MAG0] = ELFMAG0;
283 ehdr->e_ident[EI_MAG1] = ELFMAG1;
284 ehdr->e_ident[EI_MAG2] = ELFMAG2;
285 ehdr->e_ident[EI_MAG3] = ELFMAG3;
286 ehdr->e_ident[EI_CLASS] = ELF_CLASS;
287 ehdr->e_ident[EI_DATA] = ELF_DATA;
288 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
289 ehdr->e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
290 ehdr->e_ident[EI_ABIVERSION] = 0;
291 ehdr->e_ident[EI_PAD] = 0;
292 ehdr->e_type = ET_CORE;
293 ehdr->e_machine = ELF_ARCH;
294 ehdr->e_version = EV_CURRENT;
296 ehdr->e_phoff = phoff;
298 ehdr->e_ehsize = sizeof(Elf_Ehdr);
299 ehdr->e_phentsize = sizeof(Elf_Phdr);
300 ehdr->e_phnum = numsegs + 1;
301 ehdr->e_shentsize = sizeof(Elf_Shdr);
303 ehdr->e_shstrndx = SHN_UNDEF;
306 * Fill in the program header entries.
308 phdr = (Elf_Phdr *)((char *)dst + phoff);
310 /* The note segement. */
311 phdr->p_type = PT_NOTE;
312 phdr->p_offset = noteoff;
315 phdr->p_filesz = notesz;
321 /* All the writable segments from the program. */
324 each_writable_segment(map, cb_put_phdr, &phc);
329 * Emit one note section to "dst", or just size it if "dst" is NULL.
332 elf_putnote(void *dst, size_t *off, const char *name, int type,
333 const void *desc, size_t descsz)
337 note.n_namesz = strlen(name) + 1;
338 note.n_descsz = descsz;
341 bcopy(¬e, (char *)dst + *off, sizeof note);
344 bcopy(name, (char *)dst + *off, note.n_namesz);
345 *off += roundup2(note.n_namesz, sizeof(Elf_Size));
347 bcopy(desc, (char *)dst + *off, note.n_descsz);
348 *off += roundup2(note.n_descsz, sizeof(Elf_Size));
352 * Free the memory map.
355 freemap(vm_map_entry_t map)
357 while (map != NULL) {
358 vm_map_entry_t next = map->next;
365 * Read the process information necessary to fill in the core file's header.
368 readhdrinfo(pid_t pid, prstatus_t *status, prfpregset_t *fpregset,
377 memset(status, 0, sizeof *status);
378 status->pr_version = PRSTATUS_VERSION;
379 status->pr_statussz = sizeof(prstatus_t);
380 status->pr_gregsetsz = sizeof(gregset_t);
381 status->pr_fpregsetsz = sizeof(fpregset_t);
382 status->pr_osreldate = __FreeBSD_version;
383 status->pr_pid = pid;
385 memset(fpregset, 0, sizeof *fpregset);
387 memset(psinfo, 0, sizeof *psinfo);
388 psinfo->pr_version = PRPSINFO_VERSION;
389 psinfo->pr_psinfosz = sizeof(prpsinfo_t);
391 /* Read the general registers. */
392 snprintf(name, sizeof name, "/proc/%d/regs", pid);
393 if ((fd = open(name, O_RDONLY)) == -1)
394 err(1, "cannot open %s", name);
395 if ((n = read(fd, &status->pr_reg, sizeof status->pr_reg)) == -1)
396 err(1, "read error from %s", name);
397 if (n < sizeof status->pr_reg)
398 errx(1, "short read from %s: wanted %u, got %d", name,
399 sizeof status->pr_reg, n);
402 /* Read the floating point registers. */
403 snprintf(name, sizeof name, "/proc/%d/fpregs", pid);
404 if ((fd = open(name, O_RDONLY)) == -1)
405 err(1, "cannot open %s", name);
406 if ((n = read(fd, fpregset, sizeof *fpregset)) == -1)
407 err(1, "read error from %s", name);
408 if (n < sizeof *fpregset)
409 errx(1, "short read from %s: wanted %u, got %d", name,
410 sizeof *fpregset, n);
413 /* Read and parse the process status. */
414 snprintf(name, sizeof name, "/proc/%d/status", pid);
415 if ((fd = open(name, O_RDONLY)) == -1)
416 err(1, "cannot open %s", name);
417 if ((n = read(fd, line, sizeof line - 1)) == -1)
418 err(1, "read error from %s", name);
421 for (i = 0; i < n && line[i] != ' '; i++)
422 psinfo->pr_fname[i] = line[i];
423 strncpy(psinfo->pr_psargs, psinfo->pr_fname, PRARGSZ);
428 * Read the process's memory map using procfs, and return a list of
429 * VM map entries. Only the non-device read/writable segments are
430 * returned. The map entries in the list aren't fully filled in; only
431 * the items we need are present.
433 static vm_map_entry_t
443 vm_map_entry_t *linkp;
445 snprintf(mapname, sizeof mapname, "/proc/%d/map", pid);
446 if ((mapfd = open(mapname, O_RDONLY)) == -1)
447 err(1, "cannot open %s", mapname);
450 * Procfs requires (for consistency) that the entire memory map
451 * be read with a single read() call. Start with a reasonbly sized
452 * buffer, and double it until it is big enough.
457 if ((mapbuf = realloc(mapbuf, bufsize + 1)) == NULL)
458 errx(1, "out of memory");
459 mapsize = read(mapfd, mapbuf, bufsize);
460 if (mapsize != -1 || errno != EFBIG)
463 /* This lseek shouldn't be necessary, but it is. */
464 lseek(mapfd, (off_t)0, SEEK_SET);
467 err(1, "read error from %s", mapname);
469 errx(1, "empty map file %s", mapname);
476 while (pos < mapsize) {
486 n = sscanf(mapbuf + pos, "%x %x %*d %*d %*x %3[-rwx]"
487 " %*d %*d %*x %*s %*s %16s%*[\n]%n",
488 &start, &end, prot, type, &len);
490 errx(1, "ill-formed line in %s", mapname);
493 /* Ignore segments of the wrong kind, and unwritable ones */
494 if (strncmp(prot, "rw", 2) != 0 ||
495 (strcmp(type, "default") != 0 &&
496 strcmp(type, "vnode") != 0 &&
497 strcmp(type, "swap") != 0))
500 if ((ent = (vm_map_entry_t)calloc(1, sizeof *ent)) == NULL)
501 errx(1, "out of memory");
504 ent->protection = VM_PROT_READ | VM_PROT_WRITE;
506 ent->protection |= VM_PROT_EXECUTE;