[uClinux-dev] execve function of linux-2.4.x of uClinux-dist-20070130 misbehavior

[=?gb2312?B?y84gaHo=?=]

Hi everybody.

cpu:  S3C4510 
toolchain: arm-elf-tools-20030314
use uClibc

I run this version of uclinux in skyeye, and find that if parameters are 
passed from commandline the invoked command often output an error, 
especially busybox, it can't work at all.

And at last, I find the pointer passed to main function is offseted 
backward by 2.

I write two programs to test execve function:

#################
invoke.c:
#################
#include <sys/wait.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>

int main(int argc, char *argv[])
{
        pid_t cpid;
        int status;
        char *cargv[5];
        char *cenvp[1];

        printf("version 2\n");
        cpid = vfork();
        if(cpid == -1) { printf("fork failed!\n"); perror("fork"); 
exit(EXIT_FAILURE); }

        if(cpid == 0) { // child
                cargv[0] = "dispargv";
                cargv[1] = "argv1";
                cargv[2] = "argv2";
                cargv[3] = "argv3";
                cargv[4] = NULL;
                cenvp[0] = NULL;
                printf("Child PID is %ld\n", (long)getpid());
                execve("/bin/dispargv", cargv, cenvp);
        }

        wait(&status);
        return 0;
}


######################
dispargv.c
######################
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[], char *envp[])
{
        int tmp = 0;
        printf("argv is: \n");

        for(tmp = 0; tmp < argc; tmp++)
        {
                printf("%d: %s\n", tmp, argv[tmp]);
        }
        return 0;
}


###################
Makefile
###################
EXEC1 = invoke
OBJS1 = invoke.o

EXEC2 = dispargv
OBJS2 = dispargv.o

all: $(EXEC1) $(EXEC2)

$(EXEC1): $(OBJS1)
        $(CC) $(LDFLAGS) -o $@ $(OBJS1) 

$(EXEC2): $(OBJS2)
        $(CC) $(LDFLAGS) -o $@ $(OBJS2)


romfs:
        $(ROMFSINST) /bin/invoke
        $(ROMFSINST) /bin/dispargv

.PHONY:
clean:
        -rm -f $(EXEC1) $(EXEC2) *.elf *.gdb *.o

############################################################

After adding them to user/testexecve and making the romfs image, when 
running:
/bin> invoke
version 2
Child PID is 10
argv is: 
0: <
1: 
2: dispargv
3: argv1

/> dispargv haha xixi wuwu
argv is: 
0: ?
1: ?
2: dispargv
3: haha

It is obviously that the argv pointer is offseted backward by 2.

Is it a bug, or something I did wrong?

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