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procps/proc/ksym.c

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16 KiB
C
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/*
* Copyright 1998-2002 by Albert Cahalan; all rights reserved.
* This file may be used subject to the terms and conditions of the
* GNU Library General Public License Version 2, or any later version
* at your option, as published by the Free Software Foundation.
* 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 Library General Public License for more details.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <stdarg.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/utsname.h>
#include "procps.h"
#include "version.h"
#include "sysinfo.h" /* smp_num_cpus */
#define KSYMS_FILENAME "/proc/ksyms"
#if 0
#undef KSYMS_FILENAME
#define KSYMS_FILENAME "/would/be/nice/to/have/this/file"
#define SYSMAP_FILENAME "/home/albert/ps/45621/System.map-hacked"
#define linux_version_code 131598 /* ? */
#define smp_num_cpus 2
#endif
#if 0
#undef KSYMS_FILENAME
#define KSYMS_FILENAME "/home/albert/ps/45621/ksyms-2.3.12"
#define SYSMAP_FILENAME "/home/albert/ps/45621/System.map-2.3.12"
#define linux_version_code 131852 /* 2.3.12 */
#define smp_num_cpus 2
#endif
#if 0
#undef KSYMS_FILENAME
#define KSYMS_FILENAME "/home/albert/ps/45621/ksyms-2.3.18ac8-MODVERS"
#define SYSMAP_FILENAME "/home/albert/ps/45621/System.map-2.3.18ac8-MODVERS"
#define linux_version_code 131858 /* 2.3.18ac8 */
#define smp_num_cpus 2
#endif
#if 0
#undef KSYMS_FILENAME
#define KSYMS_FILENAME "/home/albert/ps/45621/ksyms-2.3.18ac8-NOMODVERS"
#define SYSMAP_FILENAME "/home/albert/ps/45621/System.map-2.3.18ac8-NOMODVERS"
#define linux_version_code 131858 /* 2.3.18ac8 */
#define smp_num_cpus 2
#endif
/* These are the symbol types, with relative popularity:
* ? w machine type junk for Alpha -- odd syntax
* ? S not for i386
* 4 W not for i386
* 60 R
* 100 A
* 125 r
* 363 s not for i386
* 858 B
* 905 g generated by modutils?
* 929 G generated by modutils?
* 1301 b
* 2750 D
* 4481 d
* 11417 ?
* 13666 t
* 15442 T
*
* For i386, that is: "RArBbDd?tT"
*/
#define SYMBOL_TYPE_CHARS "Tt?dDbBrARGgsWS"
/*
* '?' is a symbol type
* '.' is part of a name (versioning?)
* "\t[]" are for the module name in /proc/ksyms
*/
#define LEGAL_SYSMAP_CHARS "0123456789_ ?.\n\t[]" \
"abcdefghijklmnopqrstuvwxyz" \
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
/* System.map lines look like:
* hex num, space, one of SYMBOL_TYPE_CHARS, space, LEGAL_SYSMAP_CHARS, \n
*
* Alpha systems can start with a few lines that have the address replaced
* by space padding and a 'w' for the type. For those lines, the last space
* is followed by something like: mikasa_primo_mv p2k_mv sable_gamma_mv
* (just one of those, always with a "_mv", then the newline)
*
* The /proc/ksyms lines are like System.map lines w/o the symbol type char.
* When odd features are used, the name part contains:
* "(.*)_R(smp_|smp2gig_|2gig_)?[0-9a-fA-F]{8,}"
* It is likely that more crap will be added...
*/
typedef struct symb {
const char *name;
unsigned long addr;
} symb;
static const symb fail = { "?", 0 };
static const char dash[] = "-";
/* These mostly rely on POSIX to make them zero. */
static symb hashtable[256];
static char *sysmap_data;
static unsigned sysmap_room;
static symb *sysmap_index;
static unsigned sysmap_count;
static char *ksyms_data;
static unsigned ksyms_room = 4096;
static symb *ksyms_index;
static unsigned ksyms_count;
static unsigned idx_room;
/*********************************/
/* Kill this: _R(smp_?|smp2gig_?|2gig_?)?[0-9a-f]{8,}$
* We kill: (_R[^A-Z]*[0-9a-f]{8,})+$
*
* The loop should almost never be taken, but it has to be there.
* It gets rid of anything that _looks_ like a version code, even
* if a real version code has already been found. This is because
* the inability to perfectly recognize a version code may lead to
* symbol mangling, which in turn leads to mismatches between the
* /proc/ksyms and System.map data files.
*/
#if 0
static void chop_version(char *arg){
char *cp;
cp = strchr(arg,'\t');
if(cp) *cp = '\0'; /* kill trailing module name first */
for(;;){
char *p;
int len = 0;
cp = strrchr(arg, 'R');
if(!cp || cp<=arg+1 || cp[-1]!='_') break;
for(p=cp; *++p; ){
switch(*p){
default:
return;
case '0' ... '9':
case 'a' ... 'f':
len++;
continue;
case 'g' ... 'z':
case '_':
len=0;
continue;
}
}
if(len<8) break;
cp[-1] = '\0';
}
}
#endif
static void chop_version(char *arg){
char *cp;
cp = strchr(arg,'\t');
if(cp) *cp = '\0'; /* kill trailing module name first */
for(;;){
int len;
cp = strrchr(arg, 'R');
if(!cp || cp<=arg+1 || cp[-1]!='_') break;
len=strlen(cp);
if(len<9) break;
if(strpbrk(cp+1,"ABCDEFGHIJKLMNOPQRSTUVWXYZ")) break;
if(strspn(cp+len-8,"0123456789abcdef")!=8) break;
cp[-1] = '\0';
}
}
/***********************************/
static const symb *search(unsigned long address, symb *idx, unsigned count){
unsigned left;
unsigned mid;
unsigned right;
if(!idx) return NULL; /* maybe not allocated */
if(address < idx[0].addr) return NULL;
if(address >= idx[count-1].addr) return idx+count-1;
left = 0;
right = count-1;
for(;;){
mid = (left + right) / 2;
if(address >= idx[mid].addr) left = mid;
if(address <= idx[mid].addr) right = mid;
if(right-left <= 1) break;
}
if(address == idx[right].addr) return idx+right;
return idx+left;
}
/*********************************/
/* allocate if needed, read, and return buffer size */
static void read_file(const char *restrict filename, char **bufp, unsigned *restrict roomp) {
int fd = 0;
ssize_t done;
char *buf = *bufp;
ssize_t total = 0;
unsigned room = *roomp;
if(!room) goto hell; /* failed before */
if(!buf) buf = malloc(room);
if(!buf) goto hell;
open_again:
fd = open(filename, O_RDONLY|O_NOCTTY|O_NONBLOCK);
if(fd<0){
switch(errno){
case EINTR: goto open_again;
default: _exit(101);
case EACCES: /* somebody screwing around? */
/* FIXME: set a flag to disable symbol lookup? */
case ENOENT:; /* no module support */
}
goto hell;
}
for(;;){
done = read(fd, buf+total, room-total-1);
if(done==0) break; /* nothing left */
if(done==-1){
if(errno==EINTR) continue; /* try again */
perror("");
goto hell;
}
if(done==(ssize_t)room-total-1){
char *tmp;
total += done;
/* more to go, but no room in buffer */
room *= 2;
tmp = realloc(buf, room);
if(!tmp) goto hell;
buf = tmp;
continue;
}
if(done>0 && done<(ssize_t)room-total-1){
total += done;
continue; /* OK, we read some. Go do more. */
}
fprintf(stderr,"%ld can't happen\n", (long)done);
/* FIXME: memory leak */
_exit(42);
}
*bufp = buf;
*roomp = room;
close(fd);
return;
hell:
if(buf) free(buf);
*bufp = NULL;
*roomp = 0; /* this function will never work again */
total = 0;
close(fd);
return;
}
/*********************************/
static int parse_ksyms(void) {
char *endp;
if(!ksyms_room || !ksyms_data) goto quiet_goodbye;
endp = ksyms_data;
ksyms_count = 0;
if(idx_room) goto bypass; /* some space already allocated */
idx_room = 512;
for(;;){
void *vp;
idx_room *= 2;
vp = realloc(ksyms_index, sizeof(symb)*idx_room);
if(!vp) goto bad_alloc;
ksyms_index = vp;
bypass:
for(;;){
char *saved;
if(!*endp) return 1;
saved = endp;
ksyms_index[ksyms_count].addr = strtoul(endp, &endp, 16);
if(endp==saved || *endp != ' ') goto bad_parse;
endp++;
ksyms_index[ksyms_count].name = endp;
saved = endp;
endp = strchr(endp,'\n');
if(!endp) goto bad_parse; /* no newline */
*endp = '\0';
chop_version(saved);
++endp;
if(++ksyms_count >= idx_room) break; /* need more space */
}
}
if(0){
bad_alloc:
fprintf(stderr, "Warning: not enough memory available\n");
}
if(0){
bad_parse:
fprintf(stderr, "Warning: "KSYMS_FILENAME" not normal\n");
}
quiet_goodbye:
idx_room = 0;
if(ksyms_data) free(ksyms_data) , ksyms_data = NULL;
ksyms_room = 0;
if(ksyms_index) free(ksyms_index) , ksyms_index = NULL;
ksyms_count = 0;
return 0;
}
/*********************************/
#define VCNT 16
static int sysmap_mmap(const char *restrict const filename, void (*message)(const char *restrict, ...)) {
struct stat sbuf;
char *endp;
int fd;
char Version[32];
fd = open(filename, O_RDONLY|O_NOCTTY|O_NONBLOCK);
if(fd<0) return 0;
if(fstat(fd, &sbuf) < 0) goto bad_open;
if(!S_ISREG(sbuf.st_mode)) goto bad_open;
if(sbuf.st_size < 5000) goto bad_open; /* if way too small */
/* Would be shared read-only, but we want '\0' after each name. */
endp = mmap(0, sbuf.st_size + 1, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
sysmap_data = endp;
while(*endp==' '){ /* damn Alpha machine types */
if(strncmp(endp," w ", 19)) goto bad_parse;
endp += 19;
endp = strchr(endp,'\n');
if(!endp) goto bad_parse; /* no newline */
if(strncmp(endp-3, "_mv\n", 4)) goto bad_parse;
endp++;
}
if(sysmap_data == (caddr_t) -1) goto bad_open;
close(fd);
fd = -1;
sprintf(Version, "Version_%d", linux_version_code);
sysmap_room = 512;
for(;;){
void *vp;
sysmap_room *= 2;
vp = realloc(sysmap_index, sizeof(symb)*sysmap_room);
if(!vp) goto bad_alloc;
sysmap_index = vp;
for(;;){
char *vstart;
if(endp - sysmap_data >= sbuf.st_size){ /* if we reached the end */
int i = VCNT; /* check VCNT times to verify this file */
if(*Version) goto bad_version;
if(!ksyms_index) return 1; /* if can not verify, assume success */
while(i--){
#if 1
const symb *findme;
const symb *map_symb;
/* Choose VCNT entries from /proc/ksyms to test */
findme = ksyms_index + (ksyms_count*i/VCNT);
/* Search for them in the System.map */
map_symb = search(findme->addr, sysmap_index, sysmap_count);
if(map_symb){
if(map_symb->addr != findme->addr) continue;
/* backup to first matching address */
while (map_symb != sysmap_index){
if (map_symb->addr != (map_symb-1)->addr) break;
map_symb--;
}
/* search for name in symbols with same address */
while (map_symb != (sysmap_index+sysmap_count)){
if (map_symb->addr != findme->addr) break;
if (!strcmp(map_symb->name,findme->name)) goto good_match;
map_symb++;
}
map_symb--; /* backup to last symbol with matching address */
message("{%s} {%s}\n",map_symb->name,findme->name);
goto bad_match;
}
good_match:;
#endif
}
return 1; /* success */
}
sysmap_index[sysmap_count].addr = strtoul(endp, &endp, 16);
if(*endp != ' ') goto bad_parse;
endp++;
if(!strchr(SYMBOL_TYPE_CHARS, *endp)) goto bad_parse;
endp++;
if(*endp != ' ') goto bad_parse;
endp++;
sysmap_index[sysmap_count].name = endp;
vstart = endp;
endp = strchr(endp,'\n');
if(!endp) goto bad_parse; /* no newline */
*endp = '\0';
++endp;
chop_version(vstart);
if(*vstart=='V' && *Version && !strcmp(Version,vstart)) *Version='\0';
if(++sysmap_count >= sysmap_room) break; /* need more space */
}
}
if(0){
bad_match:
message("Warning: %s does not match kernel data.\n", filename);
}
if(0){
bad_version:
message("Warning: %s has an incorrect kernel version.\n", filename);
}
if(0){
bad_alloc:
message("Warning: not enough memory available\n");
}
if(0){
bad_parse:
message("Warning: %s not parseable as a System.map\n", filename);
}
if(0){
bad_open:
message("Warning: %s could not be opened as a System.map\n", filename);
}
sysmap_room=0;
sysmap_count=0;
if(sysmap_index) free(sysmap_index);
sysmap_index = NULL;
if(fd>=0) close(fd);
if(sysmap_data) munmap(sysmap_data, sbuf.st_size + 1);
sysmap_data = NULL;
return 0;
}
/*********************************/
static void read_and_parse(void){
static time_t stamp; /* after data gets old, load /proc/ksyms again */
if(time(NULL) != stamp){
read_file(KSYMS_FILENAME, &ksyms_data, &ksyms_room);
parse_ksyms();
memset((void*)hashtable,0,sizeof(hashtable)); /* invalidate cache */
stamp = time(NULL);
}
}
/*********************************/
static void default_message(const char *restrict format, ...) {
va_list arg;
va_start (arg, format);
vfprintf (stderr, format, arg);
va_end (arg);
}
/*********************************/
static int use_wchan_file;
int open_psdb_message(const char *restrict override, void (*message)(const char *, ...)) {
static const char *sysmap_paths[] = {
"/boot/System.map-%s",
"/boot/System.map",
"/lib/modules/%s/System.map",
"/usr/src/linux/System.map",
"/System.map",
NULL
};
struct stat sbuf;
struct utsname uts;
char path[64];
const char **fmt = sysmap_paths;
const char *sm;
#ifdef SYSMAP_FILENAME /* debug feature */
override = SYSMAP_FILENAME;
#endif
// first allow for a user-selected System.map file
if(
(sm=override)
||
(sm=getenv("PS_SYSMAP"))
||
(sm=getenv("PS_SYSTEM_MAP"))
){
read_and_parse();
if(sysmap_mmap(sm, message)) return 0;
/* failure is better than ignoring the user & using bad data */
return -1; /* ought to return "Namelist not found." */
}
// next try the Linux 2.5.xx method
if(!stat("/proc/self/wchan", &sbuf)){
use_wchan_file = 1; // hack
return 0;
}
// finally, search for the System.map file
uname(&uts);
do{
int did_ksyms = 0;
snprintf(path, sizeof path, *fmt, uts.release);
if(!stat(path, &sbuf)){
if (did_ksyms++) read_and_parse();
if (sysmap_mmap(path, message)) return 0;
}
}while(*++fmt);
/* TODO: Without System.map, no need to keep ksyms loaded. */
return -1;
}
/***************************************/
int open_psdb(const char *restrict override) {
return open_psdb_message(override, default_message);
}
/***************************************/
const char * read_wchan_file(unsigned pid){
static char buf[64];
const char *ret = buf;
ssize_t num;
int fd;
snprintf(buf, sizeof buf, "/proc/%d/wchan", pid);
fd = open(buf, O_RDONLY);
if(fd==-1) return "?";
num = read(fd, buf, sizeof buf - 1);
close(fd);
if(num<1) return "?"; // allow for "0"
buf[num] = '\0';
if(buf[0]=='0' && buf[1]=='\0') return "-";
// would skip over numbers if they existed -- but no
switch(*ret){
case 's': if(!strncmp(ret, "sys_", 4)) ret += 4; break;
case 'd': if(!strncmp(ret, "do_", 3)) ret += 3; break;
case '_': while(*ret=='_') ret++; break;
}
return ret;
}
/***************************************/
#define MAX_OFFSET (0x1000*sizeof(long)) /* past this is generally junk */
/* return pointer to temporary static buffer with function name */
const char * wchan(unsigned long address, unsigned pid) {
const symb *mod_symb;
const symb *map_symb;
const symb *good_symb;
const char *ret;
unsigned hash;
// can't cache it due to a race condition :-(
if(use_wchan_file) return read_wchan_file(pid);
if(!address) return dash;
read_and_parse();
hash = (address >> 4) & 0xff; /* got 56/63 hits & 7/63 misses */
if(hashtable[hash].addr == address) return hashtable[hash].name;
mod_symb = search(address, ksyms_index, ksyms_count);
if(!mod_symb) mod_symb = &fail;
map_symb = search(address, sysmap_index, sysmap_count);
if(!map_symb) map_symb = &fail;
/* which result is closest? */
good_symb = (mod_symb->addr > map_symb->addr)
? mod_symb
: map_symb
;
if(address > good_symb->addr + MAX_OFFSET) good_symb = &fail;
/* good_symb->name has the data, but needs to be trimmed */
ret = good_symb->name;
switch(*ret){
case 's': if(!strncmp(ret, "sys_", 4)) ret += 4; break;
case 'd': if(!strncmp(ret, "do_", 3)) ret += 3; break;
case '_': while(*ret=='_') ret++; break;
}
/* if(!*ret) ret = fail.name; */ /* not likely (name was "sys_", etc.) */
/* cache name after abbreviation */
hashtable[hash].addr = address;
hashtable[hash].name = ret;
return ret;
}
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