[redis-db] Confused about setproctitle

[v***@gmail.com]

In setproctitle.c

Function spt_init(int argc, char *argv[]) wrote like this

void spt_init(int argc, char *argv[]) {
char **envp = environ;
char *base, *end, *nul, *tmp;
int i, error;

if (!(base = argv[0]))
return;

nul = &base[strlen(base)];
end = nul + 1;

for (i = 0; i < argc || (i >= argc && argv[i]); i++) {
if (!argv[i] || argv[i] < end)
continue;

end = argv[i] + strlen(argv[i]) + 1;
}

for (i = 0; envp[i]; i++) {
if (envp[i] < end)
continue;

end = envp[i] + strlen(envp[i]) + 1;
}

Why there are "i >= argc && argv[i]"?
I think that if i>=argc, then the argv[i] will have index out of array
problem.

[v***@gmail.com]

I have wrote a test program to print the memory of argv and envrion.
And figured out the reason of the code.
The memory of argv and envrion are like this:
----------------------------------------------------------------------------------------------------------
| argv[0] | argv[1] | ...| argv[argc-1] | NULL | envrion[0] | ... |
envrion[last] | NULL |
----------------------------------------------------------------------------------------------------------
The argv[i] will not have index out of array problem,
and make SPT.base->argv[0], SPT.end->envrion[last].
So that setproctitle can work properly.