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-/*
- ksym_mod.c - functions for building symbol lookup tables for klogd
- Copyright (c) 1995, 1996 Dr. G.W. Wettstein <greg@wind.rmcc.com>
- Copyright (c) 1996 Enjellic Systems Development
-
- This file is part of the sysklogd package, a kernel and system log daemon.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
-
-/*
- * This file implements functions which are useful for building
- * a symbol lookup table based on the in kernel symbol table
- * maintained by the Linux kernel.
- *
- * Proper logging of kernel panics generated by loadable modules
- * tends to be difficult. Since the modules are loaded dynamically
- * their addresses are not known at kernel load time. A general
- * protection fault (Oops) cannot be properly deciphered with
- * classic methods using the static symbol map produced at link time.
- *
- * One solution to this problem is to have klogd attempt to translate
- * addresses from module when the fault occurs. By referencing the
- * the kernel symbol table proper resolution of these symbols is made
- * possible.
- *
- * At least that is the plan.
- *
- * Wed Aug 21 09:20:09 CDT 1996: Dr. Wettstein
- * The situation where no module support has been compiled into a
- * kernel is now detected. An informative message is output indicating
- * that the kernel has no loadable module support whenever kernel
- * module symbols are loaded.
- *
- * An informative message is printed indicating the number of kernel
- * modules and the number of symbols loaded from these modules.
- *
- * Sun Jun 15 16:23:29 MET DST 1997: Michael Alan Dorman
- * Some more glibc patches made by <mdorman@debian.org>.
- *
- * Sat Jan 10 15:00:18 CET 1998: Martin Schulze <joey@infodrom.north.de>
- * Fixed problem with klogd not being able to be built on a kernel
- * newer than 2.1.18. It was caused by modified structures
- * inside the kernel that were included. I have worked in a
- * patch from Alessandro Suardi <asuardi@uninetcom.it>.
- *
- * Sun Jan 25 20:57:34 CET 1998: Martin Schulze <joey@infodrom.north.de>
- * Another patch for Linux/alpha by Christopher C Chimelis
- * <chris@classnet.med.miami.edu>.
- *
- * Thu Mar 19 23:39:29 CET 1998: Manuel Rodrigues <pmanuel@cindy.fe.up.pt>
- * Changed lseek() to llseek() in order to support > 2GB address
- * space which provided by kernels > 2.1.70.
- *
- * Mon Apr 13 18:18:45 CEST 1998: Martin Schulze <joey@infodrom.north.de>
- * Removed <sys/module.h> as it's no longer part of recent glibc
- * versions. Added prototyp for llseek() which has been
- * forgotton in <unistd.h> from glibc. Added more log
- * information if problems occurred while reading a system map
- * file, by submission from Mark Simon Phillips <M.S.Phillips@nortel.co.uk>.
- *
- * Sun Jan 3 18:38:03 CET 1999: Martin Schulze <joey@infodrom.north.de>
- * Corrected return value of AddModule if /dev/kmem can't be
- * loaded. This will prevent klogd from segfaulting if /dev/kmem
- * is not available. Patch from Topi Miettinen <tom@medialab.sonera.net>.
- *
- * Tue Sep 12 23:11:13 CEST 2000: Martin Schulze <joey@infodrom.ffis.de>
- * Changed llseek() to lseek64() in order to skip a libc warning.
- */
-
-
-/* Includes. */
-#include <stdlib.h>
-#include <malloc.h>
-#include <unistd.h>
-#include <signal.h>
-#include <errno.h>
-#include <sys/fcntl.h>
-#include <sys/stat.h>
-#if !defined(__GLIBC__)
-#include <linux/time.h>
-#include <linux/module.h>
-#else /* __GLIBC__ */
-#include <linux/module.h>
-extern __off64_t lseek64 __P ((int __fd, __off64_t __offset, int __whence));
-extern int get_kernel_syms __P ((struct kernel_sym *__table));
-#endif /* __GLIBC__ */
-#include <stdarg.h>
-#include <paths.h>
-#include <linux/version.h>
-
-#include "klogd.h"
-#include "ksyms.h"
-
-
-#if !defined(__GLIBC__)
-/*
- * The following bit uses some kernel/library magic to product what
- * looks like a function call to user level code. This function is
- * actually a system call in disguise. The purpose of the getsyms
- * call is to return a current copy of the in-kernel symbol table.
- */
-#define __LIBRARY__
-#include <linux/unistd.h>
-#define __NR_getsyms __NR_get_kernel_syms
-_syscall1(int, getsyms, struct kernel_sym *, syms);
-#undef __LIBRARY__
-extern int getsyms(struct kernel_sym *);
-#else /* __GLIBC__ */
-#define getsyms get_kernel_syms
-#endif /* __GLIBC__ */
-
-/* Variables static to this module. */
-struct sym_table
-{
- unsigned long value;
- char *name;
-};
-
-struct Module
-{
- struct sym_table *sym_array;
- int num_syms;
-
- char *name;
- struct module module;
-#if LINUX_VERSION_CODE >= 0x20112
- struct module_info module_info;
-#endif
-};
-
-static int num_modules = 0;
-struct Module *sym_array_modules = (struct Module *) 0;
-
-static int have_modules = 0;
-
-#if defined(TEST)
-static int debugging = 1;
-#else
-extern int debugging;
-#endif
-
-
-/* Function prototypes. */
-static void FreeModules(void);
-static int AddSymbol(struct Module *mp, unsigned long, char *);
-static int AddModule(unsigned long, char *);
-static int symsort(const void *, const void *);
-
-
-/**************************************************************************
- * Function: InitMsyms
- *
- * Purpose: This function is responsible for building a symbol
- * table which can be used to resolve addresses for
- * loadable modules.
- *
- * Arguements: Void
- *
- * Return: A boolean return value is assumed.
- *
- * A false value indicates that something went wrong.
- *
- * True if loading is successful.
- **************************************************************************/
-
-extern int InitMsyms()
-
-{
- auto int rtn,
- tmp;
-
- auto struct kernel_sym *ksym_table,
- *p;
-
-
- /* Initialize the kernel module symbol table. */
- FreeModules();
-
-
- /*
- * The system call which returns the kernel symbol table has
- * essentialy two modes of operation. Called with a null pointer
- * the system call returns the number of symbols defined in the
- * the table.
- *
- * The second mode of operation is to pass a valid pointer to
- * the call which will then load the current symbol table into
- * the memory provided.
- *
- * Returning the symbol table is essentially an all or nothing
- * proposition so we need to pre-allocate enough memory for the
- * complete table regardless of how many symbols we need.
- *
- * Bummer.
- */
- if ( (rtn = getsyms((struct kernel_sym *) 0)) < 0 )
- {
- if ( errno == ENOSYS )
- Syslog(LOG_INFO, "No module symbols loaded - "
- "kernel modules not enabled.\n");
- else
- Syslog(LOG_ERR, "Error loading kernel symbols " \
- "- %s\n", strerror(errno));
- return(0);
- }
- if ( debugging )
- fprintf(stderr, "Loading kernel module symbols - "
- "Size of table: %d\n", rtn);
-
- ksym_table = (struct kernel_sym *) malloc(rtn * \
- sizeof(struct kernel_sym));
- if ( ksym_table == (struct kernel_sym *) 0 )
- {
- Syslog(LOG_WARNING, " Failed memory allocation for kernel " \
- "symbol table.\n");
- return(0);
- }
- if ( (rtn = getsyms(ksym_table)) < 0 )
- {
- Syslog(LOG_WARNING, "Error reading kernel symbols - %s\n", \
- strerror(errno));
- return(0);
- }
-
-
- /*
- * Build a symbol table compatible with the other one used by
- * klogd.
- */
- tmp = rtn;
- p = ksym_table;
- while ( tmp-- )
- {
- if ( !AddModule(p->value, p->name) )
- {
- Syslog(LOG_WARNING, "Error adding kernel module table "
- "entry.\n");
- free(ksym_table);
- return(0);
- }
- ++p;
- }
-
- /* Sort the symbol tables in each module. */
- for (rtn = tmp= 0; tmp < num_modules; ++tmp)
- {
- rtn += sym_array_modules[tmp].num_syms;
- if ( sym_array_modules[tmp].num_syms < 2 )
- continue;
- qsort(sym_array_modules[tmp].sym_array, \
- sym_array_modules[tmp].num_syms, \
- sizeof(struct sym_table), symsort);
- }
-
- if ( rtn == 0 )
- Syslog(LOG_INFO, "No module symbols loaded.");
- else
- Syslog(LOG_INFO, "Loaded %d %s from %d module%s", rtn, \
- (rtn == 1) ? "symbol" : "symbols", \
- num_modules, (num_modules == 1) ? "." : "s.");
- free(ksym_table);
- return(1);
-}
-
-
-static int symsort(p1, p2)
-
- const void *p1;
-
- const void *p2;
-
-{
- auto const struct sym_table *sym1 = p1,
- *sym2 = p2;
-
- if ( sym1->value < sym2->value )
- return(-1);
- if ( sym1->value == sym2->value )
- return(0);
- return(1);
-}
-
-
-/**************************************************************************
- * Function: FreeModules
- *
- * Purpose: This function is used to free all memory which has been
- * allocated for the modules and their symbols.
- *
- * Arguements: None specified.
- *
- * Return: void
- **************************************************************************/
-
-static void FreeModules()
-
-{
- auto int nmods,
- nsyms;
-
- auto struct Module *mp;
-
-
- /* Check to see if the module symbol tables need to be cleared. */
- have_modules = 0;
- if ( num_modules == 0 )
- return;
-
-
- for (nmods= 0; nmods < num_modules; ++nmods)
- {
- mp = &sym_array_modules[nmods];
- if ( mp->num_syms == 0 )
- continue;
-
- for (nsyms= 0; nsyms < mp->num_syms; ++nsyms)
- free(mp->sym_array[nsyms].name);
- free(mp->sym_array);
- }
-
- free(sym_array_modules);
- sym_array_modules = (struct Module *) 0;
- num_modules = 0;
- return;
-}
-
-
-/**************************************************************************
- * Function: AddModule
- *
- * Purpose: This function is responsible for adding a module to
- * the list of currently loaded modules.
- *
- * Arguements: (unsigned long) address, (char *) symbol
- *
- * address:-> The address of the module.
- *
- * symbol:-> The name of the module.
- *
- * Return: int
- **************************************************************************/
-
-static int AddModule(address, symbol)
-
- unsigned long address;
-
- char *symbol;
-
-{
- auto int memfd;
-
- auto struct Module *mp;
-
-
- /* Return if we have loaded the modules. */
- if ( have_modules )
- return(1);
-
- /*
- * The following section of code is responsible for determining
- * whether or not we are done reading the list of modules.
- */
- if ( symbol[0] == '#' )
- {
-
- if ( symbol[1] == '\0' )
- {
- /*
- * A symbol which consists of a # sign only
- * signifies a a resident kernel segment. When we
- * hit one of these we are done reading the
- * module list.
- */
- have_modules = 1;
- return(1);
- }
- /* Allocate space for the module. */
- sym_array_modules = (struct Module *) \
- realloc(sym_array_modules, \
- (num_modules+1) * sizeof(struct Module));
- if ( sym_array_modules == (struct Module *) 0 )
- {
- Syslog(LOG_WARNING, "Cannot allocate Module array.\n");
- return(0);
- }
- mp = &sym_array_modules[num_modules];
-
- if ( (memfd = open("/dev/kmem", O_RDONLY)) < 0 )
- {
- Syslog(LOG_WARNING, "Error opening /dev/kmem\n");
- return(0);
- }
- if ( lseek64(memfd, address, SEEK_SET) < 0 )
- {
- Syslog(LOG_WARNING, "Error seeking in /dev/kmem\n");
- Syslog(LOG_WARNING, "Symbol %s, value %08x\n", symbol, address);
- return(0);
- }
- if ( read(memfd, \
- (char *)&sym_array_modules[num_modules].module, \
- sizeof(struct module)) < 0 )
- {
- Syslog(LOG_WARNING, "Error reading module "
- "descriptor.\n");
- return(0);
- }
- close(memfd);
-
- /* Save the module name. */
- mp->name = (char *) malloc(strlen(&symbol[1]) + 1);
- if ( mp->name == (char *) 0 )
- return(0);
- strcpy(mp->name, &symbol[1]);
-
- mp->num_syms = 0;
- mp->sym_array = (struct sym_table *) 0;
- ++num_modules;
- return(1);
- }
- else
- {
- if (num_modules > 0)
- mp = &sym_array_modules[num_modules - 1];
- else
- mp = &sym_array_modules[0];
- AddSymbol(mp, address, symbol);
- }
-
-
- return(1);
-}
-
-
-/**************************************************************************
- * Function: AddSymbol
- *
- * Purpose: This function is responsible for adding a symbol name
- * and its address to the symbol table.
- *
- * Arguements: (struct Module *) mp, (unsigned long) address, (char *) symbol
- *
- * mp:-> A pointer to the module which the symbol is
- * to be added to.
- *
- * address:-> The address of the symbol.
- *
- * symbol:-> The name of the symbol.
- *
- * Return: int
- *
- * A boolean value is assumed. True if the addition is
- * successful. False if not.
- **************************************************************************/
-
-static int AddSymbol(mp, address, symbol)
-
- struct Module *mp;
-
- unsigned long address;
-
- char *symbol;
-
-{
- auto int tmp;
-
-
- /* Allocate space for the symbol table entry. */
- mp->sym_array = (struct sym_table *) realloc(mp->sym_array, \
- (mp->num_syms+1) * sizeof(struct sym_table));
- if ( mp->sym_array == (struct sym_table *) 0 )
- return(0);
-
- /* Then the space for the symbol. */
- tmp = strlen(symbol);
- tmp += (strlen(mp->name) + 1);
- mp->sym_array[mp->num_syms].name = (char *) malloc(tmp + 1);
- if ( mp->sym_array[mp->num_syms].name == (char *) 0 )
- return(0);
- memset(mp->sym_array[mp->num_syms].name, '\0', tmp + 1);
-
- /* Stuff interesting information into the module. */
- mp->sym_array[mp->num_syms].value = address;
- strcpy(mp->sym_array[mp->num_syms].name, mp->name);
- strcat(mp->sym_array[mp->num_syms].name, ":");
- strcat(mp->sym_array[mp->num_syms].name, symbol);
- ++mp->num_syms;
-
- return(1);
-}
-
-
-/**************************************************************************
- * Function: LookupModuleSymbol
- *
- * Purpose: Find the symbol which is related to the given address from
- * a kernel module.
- *
- * Arguements: (long int) value, (struct symbol *) sym
- *
- * value:-> The address to be located.
- *
- * sym:-> A pointer to a structure which will be
- * loaded with the symbol's parameters.
- *
- * Return: (char *)
- *
- * If a match cannot be found a diagnostic string is printed.
- * If a match is found the pointer to the symbolic name most
- * closely matching the address is returned.
- **************************************************************************/
-
-extern char * LookupModuleSymbol(value, sym)
-
- unsigned long value;
-
- struct symbol *sym;
-
-{
- auto int nmod,
- nsym;
-
- auto struct sym_table *last;
-
- auto struct Module *mp;
-
-
- sym->size = 0;
- sym->offset = 0;
- if ( num_modules == 0 )
- return((char *) 0);
-
- for(nmod= 0; nmod < num_modules; ++nmod)
- {
- mp = &sym_array_modules[nmod];
-
- /*
- * Run through the list of symbols in this module and
- * see if the address can be resolved.
- */
- for(nsym= 1, last = &mp->sym_array[0];
- nsym < mp->num_syms;
- ++nsym)
- {
- if ( mp->sym_array[nsym].value > value )
- {
- sym->offset = value - last->value;
- sym->size = mp->sym_array[nsym].value - \
- last->value;
- return(last->name);
- }
- last = &mp->sym_array[nsym];
- }
-
-
- /*
- * At this stage of the game we still cannot give up the
- * ghost. There is the possibility that the address is
- * from a module which has no symbols registered with
- * the kernel. The solution is to compare the address
- * against the starting address and extant of the module
- * If it is in this range we can at least return the
- * name of the module.
- */
-#if LINUX_VERSION_CODE < 0x20112
- if ( (void *) value >= mp->module.addr &&
- (void *) value <= (mp->module.addr + \
- mp->module.size * 4096) )
-#else
- if ( value >= mp->module_info.addr &&
- value <= (mp->module_info.addr + \
- mp->module.size * 4096) )
-#endif
- {
- /*
- * A special case needs to be checked for. The above
- * conditional tells us that we are within the
- * extant of this module but symbol lookup has
- * failed.
- *
- * We need to check to see if any symbols have
- * been defined in this module. If there have been
- * symbols defined the assumption must be made that
- * the faulting address lies somewhere beyond the
- * last symbol. About the only thing we can do
- * at this point is use an offset from this
- * symbol.
- */
- if ( mp->num_syms > 0 )
- {
- last = &mp->sym_array[mp->num_syms - 1];
-#if LINUX_VERSION_CODE < 0x20112
- sym->size = (int) mp->module.addr + \
- (mp->module.size * 4096) - value;
-#else
- sym->size = (int) mp->module_info.addr + \
- (mp->module.size * 4096) - value;
-#endif
- sym->offset = value - last->value;
- return(last->name);
- }
-
- /*
- * There were no symbols defined for this module.
- * Return the module name and the offset of the
- * faulting address in the module.
- */
- sym->size = mp->module.size * 4096;
-#if LINUX_VERSION_CODE < 0x20112
- sym->offset = (void *) value - mp->module.addr;
-#else
- sym->offset = value - mp->module_info.addr;
-#endif
- return(mp->name);
- }
- }
-
- /* It has been a hopeless exercise. */
- return((char *) 0);
-}
-
-
-/*
- * Setting the -DTEST define enables the following code fragment to
- * be compiled. This produces a small standalone program which will
- * dump the current kernel symbol table.
- */
-#if defined(TEST)
-
-#include <stdarg.h>
-
-
-extern int main(int, char **);
-
-
-int main(argc, argv)
-
- int argc;
-
- char *argv[];
-
-{
- auto int lp, syms;
-
-
- if ( !InitMsyms() )
- {
- fprintf(stderr, "Cannot load module symbols.\n");
- return(1);
- }
-
- printf("Number of modules: %d\n\n", num_modules);
-
- for(lp= 0; lp < num_modules; ++lp)
- {
- printf("Module #%d = %s, Number of symbols = %d\n", lp + 1, \
- sym_array_modules[lp].name, \
- sym_array_modules[lp].num_syms);
-
- for (syms= 0; syms < sym_array_modules[lp].num_syms; ++syms)
- {
- printf("\tSymbol #%d\n", syms + 1);
- printf("\tName: %s\n", \
- sym_array_modules[lp].sym_array[syms].name);
- printf("\tAddress: %lx\n\n", \
- sym_array_modules[lp].sym_array[syms].value);
- }
- }
-
- FreeModules();
- return(0);
-}
-
-extern void Syslog(int priority, char *fmt, ...)
-
-{
- va_list ap;
-
- va_start(ap, fmt);
- fprintf(stdout, "Pr: %d, ", priority);
- vfprintf(stdout, fmt, ap);
- va_end(ap);
- fputc('\n', stdout);
-
- return;
-}
-
-#endif