Why when I call method, execvp fails?
If you call store_commands() method anywhere in my code, execution of the command f开发者_JS百科ails for some reason.
such as my main method
int main (int argc, char * argv[]) {
char *command;
store_commands(); // problem
while ( (command = readline(" $ "))!= NULL ) { // scan stdin
rl_bind_key('\t',rl_complete);
splitCommands(&mainVars, command, argv);
}
return 0;
}
my store commands method
void store_commands() {
char *newEnv;
DIR * dir;
char *new ;
struct dirent * entry;
char *env = getenv("PATH");
do {
newEnv = strsep(&env, ":");
if(newEnv != NULL)
if(strlen(newEnv) > 0) {
dir = opendir(newEnv);
if( dir == NULL ) break;
if(flag == 1) {
flag = 0;
while((entry = readdir(dir)) != NULL) {
new = malloc(strlen(entry->d_name) + 1) ;
new = strcpy(new, entry->d_name);
commands[++count] = new; // add possible commands into an array
//printf("---%i %s\n", count ,commands[count]);
}
}
closedir(dir); // close directory
}
} while(newEnv);
}
test cases
without store_commands()
**ls**
comm[0]: 'ls' and comm[1]: '(null)' // command received here
Makefile
main.c
target
libedit.2.dylib
with store_commands()
**ls**
comm[0]: 'ls' and comm[1]: '(null)' // command received here again but....
Execution of the command is failed
: No such file or directory
You are corrupting the environment with strsep
. Call strdup
on your env
.
A minimal example:
#include <stdlib.h>
int main ()
{
char* z = getenv("PATH"); // <---- z points to the actual env, not a copy
*z = 0; // <---- corrupt the environment
system("ls"); // <---- fail
}
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