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glibc  2.9
Functions | Variables
start.c File Reference
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/exec.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <link.h>
#include <syscall.h>
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Functions

void __libc_init (int argc, char **argv, char **envp) __THROW
int main (int argc, char **argv, char **envp) __THROW
register long int sp asm ("%sp")
register long int sp fp asm ("%fp")
static void init_shlib (void _start() asm("start") void)
int syscall (int sysno,...) asm("init_syscall")
 asm ("init_syscall:\n"" clr %g1\n"" ta 0\n"" bcc 1f\n"" sethi %hi(_errno), %g1\n"" st %o0, [%g1 + %lo(_errno)]\n"" sub %g0, 1, %o0\n""1:retl\n"" nop")
static void init_shlib ()

Variables

int __data_start = 0

Function Documentation

void __libc_init ( int  argc,
char **  argv,
char **  envp 
)
register long int sp fp asm ( "%fp"  )
register long int sp asm ( "%sp"  )
asm ( "init_syscall:\n"" clr %g1\n"" ta 0\n"" bcc 1f\n"" sethi %  hi_errno,
%g1\n""st%  o0,
[%g1 + %lo(_errno)] \n""sub%  g0,
,
%o0\n""1:retl\n""nop  
)
static void init_shlib ( void _start () asm ("start")  void) [static]

Definition at line 65 of file start.c.

{
  /* It is important that these be declared `register'.
     Otherwise, when compiled without optimization, they are put on the
     stack, which loses completely after we zero the FP.  */
  register int argc;
  register char **argv, **envp;

  /* Unwind the frame built when we entered the function.  */
  asm("restore");

  /* And clear the frame pointer.  */
  fp = 0;

  /* The argument info starts after one register
     window (64 bytes) past the SP.  */
  argc = ((int *) sp)[16];
  argv = (char **) &((int *) sp)[17];
  envp = &argv[argc + 1];
  __environ = envp;

#ifndef NO_SHLIB
  init_shlib ();
#endif

  /* Allocate 24 bytes of stack space for the register save area.  */
  sp -= 24;
  __libc_init (argc, argv, envp);

  exit (main (argc, argv, envp));
}

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static void init_shlib ( ) [static]

Definition at line 125 of file start.c.

{
  extern struct link_dynamic _DYNAMIC;
  int so, zf;
  caddr_t somap;
  caddr_t sodmap;
  caddr_t sobssmap;
  void (*ldstart) (int, int);
  struct exec soexec;
  struct
    {
      caddr_t crt_ba;
      int crt_dzfd;
      int crt_ldfd;
      struct link_dynamic *crt_dp;
      char **crt_ep;
      caddr_t crt_bp;
    } soarg;

  /* If not dynamically linked, do nothing.  */
  if (&_DYNAMIC == 0)
    return;

  /* Map in the dynamic linker.  */
  so = syscall (SYS_open, "/usr/lib/ld.so", O_RDONLY);
  if (syscall (SYS_read, so, &soexec, sizeof (soexec)) != sizeof (soexec)
      || soexec.a_magic != ZMAGIC)
    {
      static const char emsg[] = "crt0: no /usr/lib/ld.so\n";

      syscall (SYS_write, 2, emsg, sizeof (emsg) - 1);
      syscall (SYS_exit, 127);
    }
  somap = (caddr_t) syscall (SYS_mmap, 0,
                          soexec.a_text + soexec.a_data + soexec.a_bss,
                          PROT_READ | PROT_EXEC, _MAP_NEW | MAP_PRIVATE,
                          so, 0);
  sodmap = (caddr_t) syscall (SYS_mmap, somap + soexec.a_text, soexec.a_data,
                           PROT_READ | PROT_WRITE | PROT_EXEC,
                           _MAP_NEW | MAP_FIXED | MAP_PRIVATE,
                           so, soexec.a_text);
  zf = syscall (SYS_open, "/dev/zero", O_RDONLY);
  if (soexec.a_bss != 0)
    sobssmap = (caddr_t) syscall (SYS_mmap,
                              somap + soexec.a_text + soexec.a_data,
                              soexec.a_bss,
                              PROT_READ | PROT_WRITE | PROT_EXEC,
                              _MAP_NEW | MAP_FIXED | MAP_PRIVATE,
                              zf, 0);

  /* Call the entry point of the dynamic linker.  */
  soarg.crt_ba = somap;
  soarg.crt_dzfd = zf;
  soarg.crt_ldfd = so;
  soarg.crt_dp = &_DYNAMIC;
  soarg.crt_ep = __environ;
  soarg.crt_bp = (caddr_t) &&retaddr;

  ldstart = (__typeof (ldstart)) (somap + soexec.a_entry);
  (*ldstart) (1, (char *) &soarg - (char *) sp);

 retaddr:
}

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int main ( int  argc,
char **  argv,
char **  envp 
)
int syscall ( int  sysno,
  ... 
)

Variable Documentation

Definition at line 54 of file start.c.