Avoid stack munching stdio implementations.
-Erik
This commit is contained in:
Eric Andersen
parent
3b79370a7d
commit
c06391be0d
@ -9,13 +9,13 @@
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*/
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#include <sys/utsname.h>
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#include <stdio.h>
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#include <getopt.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <syslog.h>
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#include <string.h>
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#include <ctype.h>
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#include <fcntl.h>
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#include "busybox.h"
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@ -46,11 +46,11 @@ static int autoclean, show_only, quiet, do_syslog, verbose;
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static struct dep_t *build_dep ( void )
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{
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int fd, n;
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struct utsname un;
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FILE *f;
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struct dep_t *first = 0;
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struct dep_t *current = 0;
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char buffer [4096];
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char buffer[256];
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char *filename = buffer;
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int continuation_line = 0;
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@ -58,21 +58,35 @@ static struct dep_t *build_dep ( void )
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return 0;
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// check for buffer overflow in following code
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if ( xstrlen ( un. release ) > ( sizeof( buffer ) - 64 ))
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if ( xstrlen ( un.release ) > ( sizeof( buffer ) - 64 )) {
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return 0;
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}
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strcpy ( filename, "/lib/modules/" );
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strcat ( filename, un. release );
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strcat ( filename, un.release );
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strcat ( filename, "/modules.dep" );
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f = fopen ( filename, "r" );
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if ( !f )
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if ((fd = open ( filename, O_RDONLY )) < 0)
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return 0;
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while ( fgets ( buffer, sizeof( buffer), f )) {
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int l = xstrlen ( buffer );
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while ( (n = read(fd, buffer, 255)) > 0) {
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int l;
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char *p = 0;
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/* Jump through hoops to simulate how fgets() grabs just one line at a
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* time... Don't use any stdio since modprobe gets called from a kernel
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* thread and stdio junk can overflow the limited stack... */
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p = strchr ( buffer, '\n' );
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if (p) {
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off_t offset;
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/* Get the current file descriptor offset */
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offset = lseek(fd, 0L, SEEK_CUR);
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/* Set the file descriptor offset to right after the \n */
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lseek(fd, offset-n+p-buffer+1, SEEK_SET);
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*(p+1)='\0';
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}
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l = xstrlen ( buffer );
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while ( isspace ( buffer [l-1] )) {
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buffer [l-1] = 0;
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l--;
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@ -105,10 +119,10 @@ static struct dep_t *build_dep ( void )
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mod = xstrndup ( mods, col - mods - ext );
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if ( !current ) {
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first = current = (struct dep_t *) malloc ( sizeof ( struct dep_t ));
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first = current = (struct dep_t *) xmalloc ( sizeof ( struct dep_t ));
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}
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else {
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current-> m_next = (struct dep_t *) malloc ( sizeof ( struct dep_t ));
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current-> m_next = (struct dep_t *) xmalloc ( sizeof ( struct dep_t ));
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current = current-> m_next;
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}
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current-> m_module = mod;
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@ -164,79 +178,90 @@ static struct dep_t *build_dep ( void )
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else
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continuation_line = 0;
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}
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fclose ( f );
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close ( fd );
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// alias parsing is not 100% correct (no correct handling of continuation lines within an alias) !
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f = fopen ( "/etc/modules.conf", "r" );
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if ( !f )
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f = fopen ( "/etc/conf.modules", "r" );
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if ( f ) {
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continuation_line = 0;
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if ((fd = open ( "/etc/modules.conf", O_RDONLY )) < 0)
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if ((fd = open ( "/etc/conf.modules", O_RDONLY )) < 0)
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return first;
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while ( fgets ( buffer, sizeof( buffer), f )) {
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int l;
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char *p;
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p = strchr ( buffer, '#' );
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if ( p )
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*p = 0;
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l = xstrlen ( buffer );
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continuation_line = 0;
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while ( read(fd, buffer, 255) > 0) {
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int l;
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char *p;
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while ( l && isspace ( buffer [l-1] )) {
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buffer [l-1] = 0;
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l--;
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}
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if ( l == 0 ) {
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continuation_line = 0;
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continue;
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}
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if ( !continuation_line ) {
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if (( strncmp ( buffer, "alias", 5 ) == 0 ) && isspace ( buffer [5] )) {
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char *alias, *mod;
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alias = buffer + 6;
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while ( isspace ( *alias ))
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alias++;
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mod = alias;
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while ( !isspace ( *mod ))
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mod++;
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*mod = 0;
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mod++;
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while ( isspace ( *mod ))
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mod++;
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// fprintf ( stderr, "ALIAS: '%s' -> '%s'\n", alias, mod );
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if ( !current ) {
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first = current = (struct dep_t *) malloc ( sizeof ( struct dep_t ));
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}
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else {
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current-> m_next = (struct dep_t *) malloc ( sizeof ( struct dep_t ));
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current = current-> m_next;
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}
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current-> m_module = xstrdup ( alias );
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current-> m_isalias = 1;
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if (( strcmp ( alias, "off" ) == 0 ) || ( strcmp ( alias, "null" ) == 0 )) {
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current-> m_depcnt = 0;
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current-> m_deparr = 0;
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}
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else {
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current-> m_depcnt = 1;
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current-> m_deparr = xmalloc ( 1 * sizeof( char * ));
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current-> m_deparr[0] = xstrdup ( mod );
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}
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current-> m_next = 0;
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}
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}
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/* Jump through hoops to simulate how fgets() grabs just one line at a
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* time... Don't use any stdio since modprobe gets called from a kernel
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* thread and stdio junk can overflow the limited stack... */
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p = strchr ( buffer, '\n' );
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if (p) {
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off_t offset;
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/* Get the current file descriptor offset */
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offset = lseek(fd, 0L, SEEK_CUR);
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/* Set the file descriptor offset to right after the \n */
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lseek(fd, offset-n+p-buffer+1, SEEK_SET);
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*(p+1)='\0';
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}
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p = strchr ( buffer, '#' );
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if ( p )
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*p = 0;
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l = xstrlen ( buffer );
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while ( l && isspace ( buffer [l-1] )) {
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buffer [l-1] = 0;
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l--;
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}
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if ( l == 0 ) {
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continuation_line = 0;
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continue;
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}
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if ( !continuation_line ) {
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if (( strncmp ( buffer, "alias", 5 ) == 0 ) && isspace ( buffer [5] )) {
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char *alias, *mod;
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alias = buffer + 6;
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while ( isspace ( *alias ))
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alias++;
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mod = alias;
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while ( !isspace ( *mod ))
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mod++;
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*mod = 0;
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mod++;
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while ( isspace ( *mod ))
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mod++;
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// fprintf ( stderr, "ALIAS: '%s' -> '%s'\n", alias, mod );
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if ( !current ) {
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first = current = (struct dep_t *) xmalloc ( sizeof ( struct dep_t ));
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}
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else {
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current-> m_next = (struct dep_t *) xmalloc ( sizeof ( struct dep_t ));
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current = current-> m_next;
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}
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current-> m_module = xstrdup ( alias );
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current-> m_isalias = 1;
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if (( strcmp ( alias, "off" ) == 0 ) || ( strcmp ( alias, "null" ) == 0 )) {
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current-> m_depcnt = 0;
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current-> m_deparr = 0;
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}
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else {
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current-> m_depcnt = 1;
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current-> m_deparr = xmalloc ( 1 * sizeof( char * ));
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current-> m_deparr[0] = xstrdup ( mod );
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}
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current-> m_next = 0;
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}
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}
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fclose ( f );
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}
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close ( fd );
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return first;
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}
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