#include "symbol.h"
#include "debug.h"
-#ifndef HAVE_ELF_GETPHDRNUM
+#ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
static int elf_getphdrnum(Elf *elf, size_t *dst)
{
GElf_Ehdr gehdr;
ek = elf_kind(elf);
if (ek != ELF_K_ELF)
- goto out_close;
+ goto out_elf_end;
if (gelf_getehdr(elf, &ehdr) == NULL) {
pr_err("%s: cannot get elf header.\n", __func__);
- goto out_close;
+ goto out_elf_end;
}
sec = elf_section_by_name(elf, &ehdr, &shdr,
".gnu_debuglink", NULL);
if (sec == NULL)
- goto out_close;
+ goto out_elf_end;
data = elf_getdata(sec, NULL);
if (data == NULL)
- goto out_close;
+ goto out_elf_end;
/* the start of this section is a zero-terminated string */
strncpy(debuglink, data->d_buf, size);
+out_elf_end:
elf_end(elf);
-
out_close:
close(fd);
out:
return err;
}
+static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
+{
+ ssize_t r;
+ size_t n;
+ int err = -1;
+ char *buf = malloc(page_size);
+
+ if (buf == NULL)
+ return -1;
+
+ if (lseek(to, to_offs, SEEK_SET) != to_offs)
+ goto out;
+
+ if (lseek(from, from_offs, SEEK_SET) != from_offs)
+ goto out;
+
+ while (len) {
+ n = page_size;
+ if (len < n)
+ n = len;
+ /* Use read because mmap won't work on proc files */
+ r = read(from, buf, n);
+ if (r < 0)
+ goto out;
+ if (!r)
+ break;
+ n = r;
+ r = write(to, buf, n);
+ if (r < 0)
+ goto out;
+ if ((size_t)r != n)
+ goto out;
+ len -= n;
+ }
+
+ err = 0;
+out:
+ free(buf);
+ return err;
+}
+
+struct kcore {
+ int fd;
+ int elfclass;
+ Elf *elf;
+ GElf_Ehdr ehdr;
+};
+
+static int kcore__open(struct kcore *kcore, const char *filename)
+{
+ GElf_Ehdr *ehdr;
+
+ kcore->fd = open(filename, O_RDONLY);
+ if (kcore->fd == -1)
+ return -1;
+
+ kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
+ if (!kcore->elf)
+ goto out_close;
+
+ kcore->elfclass = gelf_getclass(kcore->elf);
+ if (kcore->elfclass == ELFCLASSNONE)
+ goto out_end;
+
+ ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
+ if (!ehdr)
+ goto out_end;
+
+ return 0;
+
+out_end:
+ elf_end(kcore->elf);
+out_close:
+ close(kcore->fd);
+ return -1;
+}
+
+static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
+ bool temp)
+{
+ GElf_Ehdr *ehdr;
+
+ kcore->elfclass = elfclass;
+
+ if (temp)
+ kcore->fd = mkstemp(filename);
+ else
+ kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
+ if (kcore->fd == -1)
+ return -1;
+
+ kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
+ if (!kcore->elf)
+ goto out_close;
+
+ if (!gelf_newehdr(kcore->elf, elfclass))
+ goto out_end;
+
+ ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
+ if (!ehdr)
+ goto out_end;
+
+ return 0;
+
+out_end:
+ elf_end(kcore->elf);
+out_close:
+ close(kcore->fd);
+ unlink(filename);
+ return -1;
+}
+
+static void kcore__close(struct kcore *kcore)
+{
+ elf_end(kcore->elf);
+ close(kcore->fd);
+}
+
+static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
+{
+ GElf_Ehdr *ehdr = &to->ehdr;
+ GElf_Ehdr *kehdr = &from->ehdr;
+
+ memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
+ ehdr->e_type = kehdr->e_type;
+ ehdr->e_machine = kehdr->e_machine;
+ ehdr->e_version = kehdr->e_version;
+ ehdr->e_entry = 0;
+ ehdr->e_shoff = 0;
+ ehdr->e_flags = kehdr->e_flags;
+ ehdr->e_phnum = count;
+ ehdr->e_shentsize = 0;
+ ehdr->e_shnum = 0;
+ ehdr->e_shstrndx = 0;
+
+ if (from->elfclass == ELFCLASS32) {
+ ehdr->e_phoff = sizeof(Elf32_Ehdr);
+ ehdr->e_ehsize = sizeof(Elf32_Ehdr);
+ ehdr->e_phentsize = sizeof(Elf32_Phdr);
+ } else {
+ ehdr->e_phoff = sizeof(Elf64_Ehdr);
+ ehdr->e_ehsize = sizeof(Elf64_Ehdr);
+ ehdr->e_phentsize = sizeof(Elf64_Phdr);
+ }
+
+ if (!gelf_update_ehdr(to->elf, ehdr))
+ return -1;
+
+ if (!gelf_newphdr(to->elf, count))
+ return -1;
+
+ return 0;
+}
+
+static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
+ u64 addr, u64 len)
+{
+ GElf_Phdr gphdr;
+ GElf_Phdr *phdr;
+
+ phdr = gelf_getphdr(kcore->elf, idx, &gphdr);
+ if (!phdr)
+ return -1;
+
+ phdr->p_type = PT_LOAD;
+ phdr->p_flags = PF_R | PF_W | PF_X;
+ phdr->p_offset = offset;
+ phdr->p_vaddr = addr;
+ phdr->p_paddr = 0;
+ phdr->p_filesz = len;
+ phdr->p_memsz = len;
+ phdr->p_align = page_size;
+
+ if (!gelf_update_phdr(kcore->elf, idx, phdr))
+ return -1;
+
+ return 0;
+}
+
+static off_t kcore__write(struct kcore *kcore)
+{
+ return elf_update(kcore->elf, ELF_C_WRITE);
+}
+
+struct phdr_data {
+ off_t offset;
+ u64 addr;
+ u64 len;
+};
+
+struct kcore_copy_info {
+ u64 stext;
+ u64 etext;
+ u64 first_symbol;
+ u64 last_symbol;
+ u64 first_module;
+ u64 last_module_symbol;
+ struct phdr_data kernel_map;
+ struct phdr_data modules_map;
+};
+
+static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
+ u64 start)
+{
+ struct kcore_copy_info *kci = arg;
+
+ if (!symbol_type__is_a(type, MAP__FUNCTION))
+ return 0;
+
+ if (strchr(name, '[')) {
+ if (start > kci->last_module_symbol)
+ kci->last_module_symbol = start;
+ return 0;
+ }
+
+ if (!kci->first_symbol || start < kci->first_symbol)
+ kci->first_symbol = start;
+
+ if (!kci->last_symbol || start > kci->last_symbol)
+ kci->last_symbol = start;
+
+ if (!strcmp(name, "_stext")) {
+ kci->stext = start;
+ return 0;
+ }
+
+ if (!strcmp(name, "_etext")) {
+ kci->etext = start;
+ return 0;
+ }
+
+ return 0;
+}
+
+static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
+ const char *dir)
+{
+ char kallsyms_filename[PATH_MAX];
+
+ scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
+
+ if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
+ return -1;
+
+ if (kallsyms__parse(kallsyms_filename, kci,
+ kcore_copy__process_kallsyms) < 0)
+ return -1;
+
+ return 0;
+}
+
+static int kcore_copy__process_modules(void *arg,
+ const char *name __maybe_unused,
+ u64 start)
+{
+ struct kcore_copy_info *kci = arg;
+
+ if (!kci->first_module || start < kci->first_module)
+ kci->first_module = start;
+
+ return 0;
+}
+
+static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
+ const char *dir)
+{
+ char modules_filename[PATH_MAX];
+
+ scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
+
+ if (symbol__restricted_filename(modules_filename, "/proc/modules"))
+ return -1;
+
+ if (modules__parse(modules_filename, kci,
+ kcore_copy__process_modules) < 0)
+ return -1;
+
+ return 0;
+}
+
+static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
+ u64 s, u64 e)
+{
+ if (p->addr || s < start || s >= end)
+ return;
+
+ p->addr = s;
+ p->offset = (s - start) + pgoff;
+ p->len = e < end ? e - s : end - s;
+}
+
+static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
+{
+ struct kcore_copy_info *kci = data;
+ u64 end = start + len;
+
+ kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
+ kci->etext);
+
+ kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
+ kci->last_module_symbol);
+
+ return 0;
+}
+
+static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
+{
+ if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
+ return -1;
+
+ return 0;
+}
+
+static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
+ Elf *elf)
+{
+ if (kcore_copy__parse_kallsyms(kci, dir))
+ return -1;
+
+ if (kcore_copy__parse_modules(kci, dir))
+ return -1;
+
+ if (kci->stext)
+ kci->stext = round_down(kci->stext, page_size);
+ else
+ kci->stext = round_down(kci->first_symbol, page_size);
+
+ if (kci->etext) {
+ kci->etext = round_up(kci->etext, page_size);
+ } else if (kci->last_symbol) {
+ kci->etext = round_up(kci->last_symbol, page_size);
+ kci->etext += page_size;
+ }
+
+ kci->first_module = round_down(kci->first_module, page_size);
+
+ if (kci->last_module_symbol) {
+ kci->last_module_symbol = round_up(kci->last_module_symbol,
+ page_size);
+ kci->last_module_symbol += page_size;
+ }
+
+ if (!kci->stext || !kci->etext)
+ return -1;
+
+ if (kci->first_module && !kci->last_module_symbol)
+ return -1;
+
+ return kcore_copy__read_maps(kci, elf);
+}
+
+static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
+ const char *name)
+{
+ char from_filename[PATH_MAX];
+ char to_filename[PATH_MAX];
+
+ scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
+ scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
+
+ return copyfile_mode(from_filename, to_filename, 0400);
+}
+
+static int kcore_copy__unlink(const char *dir, const char *name)
+{
+ char filename[PATH_MAX];
+
+ scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
+
+ return unlink(filename);
+}
+
+static int kcore_copy__compare_fds(int from, int to)
+{
+ char *buf_from;
+ char *buf_to;
+ ssize_t ret;
+ size_t len;
+ int err = -1;
+
+ buf_from = malloc(page_size);
+ buf_to = malloc(page_size);
+ if (!buf_from || !buf_to)
+ goto out;
+
+ while (1) {
+ /* Use read because mmap won't work on proc files */
+ ret = read(from, buf_from, page_size);
+ if (ret < 0)
+ goto out;
+
+ if (!ret)
+ break;
+
+ len = ret;
+
+ if (readn(to, buf_to, len) != (int)len)
+ goto out;
+
+ if (memcmp(buf_from, buf_to, len))
+ goto out;
+ }
+
+ err = 0;
+out:
+ free(buf_to);
+ free(buf_from);
+ return err;
+}
+
+static int kcore_copy__compare_files(const char *from_filename,
+ const char *to_filename)
+{
+ int from, to, err = -1;
+
+ from = open(from_filename, O_RDONLY);
+ if (from < 0)
+ return -1;
+
+ to = open(to_filename, O_RDONLY);
+ if (to < 0)
+ goto out_close_from;
+
+ err = kcore_copy__compare_fds(from, to);
+
+ close(to);
+out_close_from:
+ close(from);
+ return err;
+}
+
+static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
+ const char *name)
+{
+ char from_filename[PATH_MAX];
+ char to_filename[PATH_MAX];
+
+ scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
+ scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
+
+ return kcore_copy__compare_files(from_filename, to_filename);
+}
+
+/**
+ * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
+ * @from_dir: from directory
+ * @to_dir: to directory
+ *
+ * This function copies kallsyms, modules and kcore files from one directory to
+ * another. kallsyms and modules are copied entirely. Only code segments are
+ * copied from kcore. It is assumed that two segments suffice: one for the
+ * kernel proper and one for all the modules. The code segments are determined
+ * from kallsyms and modules files. The kernel map starts at _stext or the
+ * lowest function symbol, and ends at _etext or the highest function symbol.
+ * The module map starts at the lowest module address and ends at the highest
+ * module symbol. Start addresses are rounded down to the nearest page. End
+ * addresses are rounded up to the nearest page. An extra page is added to the
+ * highest kernel symbol and highest module symbol to, hopefully, encompass that
+ * symbol too. Because it contains only code sections, the resulting kcore is
+ * unusual. One significant peculiarity is that the mapping (start -> pgoff)
+ * is not the same for the kernel map and the modules map. That happens because
+ * the data is copied adjacently whereas the original kcore has gaps. Finally,
+ * kallsyms and modules files are compared with their copies to check that
+ * modules have not been loaded or unloaded while the copies were taking place.
+ *
+ * Return: %0 on success, %-1 on failure.
+ */
+int kcore_copy(const char *from_dir, const char *to_dir)
+{
+ struct kcore kcore;
+ struct kcore extract;
+ size_t count = 2;
+ int idx = 0, err = -1;
+ off_t offset = page_size, sz, modules_offset = 0;
+ struct kcore_copy_info kci = { .stext = 0, };
+ char kcore_filename[PATH_MAX];
+ char extract_filename[PATH_MAX];
+
+ if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
+ return -1;
+
+ if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
+ goto out_unlink_kallsyms;
+
+ scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
+ scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
+
+ if (kcore__open(&kcore, kcore_filename))
+ goto out_unlink_modules;
+
+ if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
+ goto out_kcore_close;
+
+ if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
+ goto out_kcore_close;
+
+ if (!kci.modules_map.addr)
+ count -= 1;
+
+ if (kcore__copy_hdr(&kcore, &extract, count))
+ goto out_extract_close;
+
+ if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
+ kci.kernel_map.len))
+ goto out_extract_close;
+
+ if (kci.modules_map.addr) {
+ modules_offset = offset + kci.kernel_map.len;
+ if (kcore__add_phdr(&extract, idx, modules_offset,
+ kci.modules_map.addr, kci.modules_map.len))
+ goto out_extract_close;
+ }
+
+ sz = kcore__write(&extract);
+ if (sz < 0 || sz > offset)
+ goto out_extract_close;
+
+ if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
+ kci.kernel_map.len))
+ goto out_extract_close;
+
+ if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
+ extract.fd, modules_offset,
+ kci.modules_map.len))
+ goto out_extract_close;
+
+ if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
+ goto out_extract_close;
+
+ if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
+ goto out_extract_close;
+
+ err = 0;
+
+out_extract_close:
+ kcore__close(&extract);
+ if (err)
+ unlink(extract_filename);
+out_kcore_close:
+ kcore__close(&kcore);
+out_unlink_modules:
+ if (err)
+ kcore_copy__unlink(to_dir, "modules");
+out_unlink_kallsyms:
+ if (err)
+ kcore_copy__unlink(to_dir, "kallsyms");
+
+ return err;
+}
+
+int kcore_extract__create(struct kcore_extract *kce)
+{
+ struct kcore kcore;
+ struct kcore extract;
+ size_t count = 1;
+ int idx = 0, err = -1;
+ off_t offset = page_size, sz;
+
+ if (kcore__open(&kcore, kce->kcore_filename))
+ return -1;
+
+ strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
+ if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
+ goto out_kcore_close;
+
+ if (kcore__copy_hdr(&kcore, &extract, count))
+ goto out_extract_close;
+
+ if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
+ goto out_extract_close;
+
+ sz = kcore__write(&extract);
+ if (sz < 0 || sz > offset)
+ goto out_extract_close;
+
+ if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
+ goto out_extract_close;
+
+ err = 0;
+
+out_extract_close:
+ kcore__close(&extract);
+ if (err)
+ unlink(kce->extract_filename);
+out_kcore_close:
+ kcore__close(&kcore);
+
+ return err;
+}
+
+void kcore_extract__delete(struct kcore_extract *kce)
+{
+ unlink(kce->extract_filename);
+}
+
void symbol__elf_init(void)
{
elf_version(EV_CURRENT);
projects / ~andy / linux / blobdiff