Help with getuid Post: 302893905

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Top Forums Programming Help with getuid Post 302893905 by Corona688 on Friday 21st of March 2014 02:35:06 PM

03-21-2014

Registered User

Do you want the program to be run before the C program, or from inside the C program?

From outside:

Code:

cat <<EOF >arg.c
#include <stdio.h>
int main(int argc, char *argv[])
{
        printf("argv[1]=%s\n", argv[1]);
        return(0);
}
EOF

gcc arg.c -o arg

./arg "$(command which prints something)"

From inside:

Code:

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

int main()
{
       char buf[512];
        FILE *fp=popen("ls", "r");
        while(fgets(buf, 512, fp)) printf("Got line '%s'\n", buf);

        pclose(fp);
}

Last edited by Corona688; 03-21-2014 at 03:43 PM..

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getuid32

GETUID(2)						     Linux Programmer's Manual							 GETUID(2)

NAME

       getuid, geteuid - get user identity

SYNOPSIS

       #include <unistd.h>
       #include <sys/types.h>

       uid_t getuid(void);
       uid_t geteuid(void);

DESCRIPTION

       getuid() returns the real user ID of the calling process.

       geteuid() returns the effective user ID of the calling process.

ERRORS

       These functions are always successful.

CONFORMING TO

       POSIX.1-2001, 4.3BSD.

NOTES

   History
       In UNIX V6 the getuid() call returned (euid << 8) + uid.  UNIX V7 introduced separate calls getuid() and geteuid().

       The  original  Linux  getuid()  and  geteuid()  system  calls supported only 16-bit user IDs.  Subsequently, Linux 2.4 added getuid32() and
       geteuid32(), supporting 32-bit IDs.  The glibc getuid() and geteuid() wrapper functions transparently deal with the variations across  ker-
       nel versions.

SEE ALSO

       getresuid(2), setreuid(2), setuid(2), credentials(7)

COLOPHON

       This  page is part of release 3.53 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2010-11-22								 GETUID(2)

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getuid32