1 files changed, 601 insertions, 6 deletions

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index a9c829be5216..eed0b96302af 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -8,7 +8,7 @@
 #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;
@@ -487,27 +487,27 @@ int filename__read_debuglink(const char *filename, char *debuglink,
 
         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:
@@ -1018,6 +1018,601 @@ int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
         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);