diff options
Diffstat (limited to 'libdwfl/linux-kernel-modules.c')
| -rw-r--r-- | libdwfl/linux-kernel-modules.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/libdwfl/linux-kernel-modules.c b/libdwfl/linux-kernel-modules.c new file mode 100644 index 00000000..65e5ca2d --- /dev/null +++ b/libdwfl/linux-kernel-modules.c @@ -0,0 +1,243 @@ +/* Standard libdwfl callbacks for debugging the running Linux kernel. + Copyright (C) 2005 Red Hat, Inc. + + This program is Open Source software; you can redistribute it and/or + modify it under the terms of the Open Software License version 1.0 as + published by the Open Source Initiative. + + You should have received a copy of the Open Software License along + with this program; if not, you may obtain a copy of the Open Software + License version 1.0 from http://www.opensource.org/licenses/osl.php or + by writing the Open Source Initiative c/o Lawrence Rosen, Esq., + 3001 King Ranch Road, Ukiah, CA 95482. */ + +#include <config.h> +#undef _FILE_OFFSET_BITS /* Doesn't jibe with fts. */ + +#include "libdwflP.h" +#include <inttypes.h> +#include <errno.h> +#include <stdio.h> +#include <stdio_ext.h> +#include <string.h> +#include <stdlib.h> +#include <sys/utsname.h> +#include <fcntl.h> +#include <unistd.h> +#include <fts.h> + + +#define MODULEDIRFMT "/lib/modules/%s" + +#define MODULELIST "/proc/modules" +#define SECADDRFMT "/sys/module/%s/sections/%s" + + +static inline const char * +kernel_release (void) +{ + /* Cache the `uname -r` string we'll use. */ + static struct utsname utsname; + if (utsname.release[0] == '\0' && uname (&utsname) != 0) + return NULL; + return utsname.release; +} + +/* Find the ELF file for the running kernel and dwfl_report_elf it. */ +int +dwfl_linux_kernel_report_kernel (Dwfl *dwfl) +{ + if (dwfl == NULL) + return -1; + + const char *release = kernel_release (); + if (release == NULL) + return errno; + + char *fname = NULL; + asprintf (&fname, "/boot/vmlinux-%s", release); + if (fname == NULL) + return -1; + int fd = open64 (fname, O_RDONLY); + if (fd < 0) + { + free (fname); + fname = NULL; + asprintf (&fname, "/usr/lib/debug" MODULEDIRFMT "/vmlinux", release); + if (fname == NULL) + return -1; + fd = open64 (fname, O_RDONLY); + } + + int result = 0; + if (fd < 0) + result = errno; + else if (INTUSE(dwfl_report_elf) (dwfl, "kernel", fname, fd, 0) == NULL) + { + close (fd); + result = -1; + } + + free (fname); + + return result; +} +INTDEF (dwfl_linux_kernel_report_kernel) + +/* Dwfl_Callbacks.find_elf for the running Linux kernel and its modules. */ + +int +dwfl_linux_kernel_find_elf (Dwfl_Module *mod __attribute__ ((unused)), + void **userdata __attribute__ ((unused)), + const char *module_name, + Dwarf_Addr base __attribute__ ((unused)), + char **file_name, + Elf **elfp __attribute__ ((unused))) +{ + const char *release = kernel_release (); + if (release == NULL) + return -1; + + /* Do "find /lib/modules/`uname -r` -name MODULE_NAME.ko". */ + + char *modulesdir[] = { NULL, NULL }; + asprintf (&modulesdir[0], MODULEDIRFMT "/kernel", release); + if (modulesdir[0] == NULL) + return -1; + + FTS *fts = fts_open (modulesdir, FTS_LOGICAL | FTS_NOSTAT, NULL); + if (fts == NULL) + { + free (modulesdir[0]); + return -1; + } + + size_t namelen = strlen (module_name); + FTSENT *f; + int error = ENOENT; + while ((f = fts_read (fts)) != NULL) + { + error = ENOENT; + switch (f->fts_info) + { + case FTS_F: + case FTS_NSOK: + /* See if this file name is "MODULE_NAME.ko". */ + if (f->fts_namelen == namelen + 3 + && !memcmp (f->fts_name, module_name, namelen) + && !memcmp (f->fts_name + namelen, ".ko", 4)) + { + int fd = open64 (f->fts_accpath, O_RDONLY); + *file_name = strdup (f->fts_path); + fts_close (fts); + if (fd < 0) + free (*file_name); + else if (*file_name == NULL) + { + close (fd); + fd = -1; + } + return fd; + } + break; + + case FTS_ERR: + case FTS_DNR: + case FTS_NS: + error = f->fts_errno; + break; + + default: + break; + } + } + + errno = error; + return -1; +} +INTDEF (dwfl_linux_kernel_find_elf) + +/* Dwfl_Callbacks.section_address for kernel modules in the running Linux. + We read the information from /sys/module directly. */ + +int +dwfl_linux_kernel_module_section_address +(Dwfl_Module *mod __attribute__ ((unused)), + void **userdata __attribute__ ((unused)), + const char *modname, Dwarf_Addr base __attribute__ ((unused)), + const char *secname, Dwarf_Addr *addr) +{ + char *sysfile = NULL; + asprintf (&sysfile, SECADDRFMT, modname, secname); + if (sysfile == NULL) + return ENOMEM; + + FILE *f = fopen (sysfile, "r"); + if (f == NULL) + { + if (errno == ENOENT) + { + /* The .modinfo and .data.percpu sections are never kept + loaded in the kernel. If the kernel was compiled without + CONFIG_MODULE_UNLOAD, the .exit.* sections are not + actually loaded at all. + + Just relocate these bogusly to zero. This part of the + debug information will not be of any use. */ + + if (!strcmp (secname, ".modinfo") + || !strcmp (secname, ".data.percpu") + || !strncmp (secname, ".exit", 5)) + { + *addr = 0; + return DWARF_CB_OK; + } + } + + return DWARF_CB_ABORT; + } + + (void) __fsetlocking (f, FSETLOCKING_BYCALLER); + + int result = (fscanf (f, "%" PRIi64 "\n", addr) == 1 ? 0 + : ferror_unlocked (f) ? errno : ENOEXEC); + fclose (f); + + if (result == 0) + return DWARF_CB_OK; + + errno = result; + return DWARF_CB_ABORT; +} +INTDEF (dwfl_linux_kernel_module_section_address) + +int +dwfl_linux_kernel_report_modules (Dwfl *dwfl) +{ + FILE *f = fopen (MODULELIST, "r"); + if (f == NULL) + return errno; + + (void) __fsetlocking (f, FSETLOCKING_BYCALLER); + + int result = 0; + Dwarf_Addr modaddr; + unsigned long int modsz; + char modname[128]; + while (fscanf (f, "%128s %lu %*s %*s %*s %" PRIi64 "\n", + modname, &modsz, &modaddr) == 3) + if (INTUSE(dwfl_report_module) (dwfl, modname, + modaddr, modaddr + modsz) == NULL) + { + result = -1; + break; + } + + if (result == 0) + result = ferror_unlocked (f) ? errno : feof_unlocked (f) ? 0 : ENOEXEC; + + fclose (f); + + return result; +} +INTDEF (dwfl_linux_kernel_report_modules) |