exec question

Hello,

How can I execute a program (without the full path, just the name) using exec's system calls within a C program? ej: buf[]={"uname",NULL};

Thanks for a brief example,

ework0

Quoting ework0 <[email protected]>:

The reason you can avoid a full path with system and popen is because they first spawn a shell and then have the shell execute the program.
The shell first looks for the program in the PATH env variable.

Also to use exec you probably want to fork() first.

But then again, what does that buff variable is for? if it's ARGV, then its right to have the name for the program only, but the filename argument still needs to include the full path

i.e.

execv("/bin/uname", buff);

would execute /bin/uname, and if it happened to read it's first parameter (argv[0]) it would find the string "uname"
there would also be no more parameters (argc == 1)

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I believe this is what you want, right?

In the future, you will get a much more expedient response by posting to the newsgroup, comp.unix.programmer. :) Just an FYI .. not trying to scare you away.

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

int
main(int argc, char *argv[])

{
	/* In using execlp you better be sure PATH is set properly and
	 * also in ceratin situations it might be a security risk.
	 */
	/* Uncomment below if you want an example with arguments */
        //if (execlp("cat", "cat", "/etc/hosts", (char *)0) < 0)
        if (execlp("df", "df", (char *)NULL) < 0)
                fprintf(stderr, "\nCannot exec!\n");

        exit(0);
}