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

enum { BUFFERSIZE = 512 };

void func(const char *input) {
  char cmdbuf[BUFFERSIZE];
  int len_wanted = snprintf(cmdbuf, BUFFERSIZE,
                            "any_cmd '%s'", input);
  if (len_wanted >= BUFFERSIZE) {
    /* Handle error */
  } else if (len_wanted < 0) {
    /* Handle error */
  } else if (system(cmdbuf) == -1) {
    /* Handle error */
  }
}

#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
 
void func(char *input) {
  pid_t pid;
  int status;
  pid_t ret;
  char *const args[3] = {"any_exe", input, NULL};
  char **env;
  extern char **environ;

  /* ... Sanitize arguments ... */

  pid = fork();
  if (pid == -1) {
    /* Handle error */
  } else if (pid != 0) {
    while ((ret = waitpid(pid, &status, 0)) == -1) {
      if (errno != EINTR) {
        /* Handle error */
        break;
      }
    }
    if ((ret != -1) &&
      (!WIFEXITED(status) || !WEXITSTATUS(status)) ) {
      /* Report unexpected child status */
    }
  } else {
    /* ... Initialize env as a sanitized copy of environ ... */
    if (execve("/usr/bin/any_cmd", args, env) == -1) {
      /* Handle error */
      _Exit(127);
    }
  }
}

#include <pwd.h>
#include <unistd.h>
#include <string.h>
 #include <stdlib.h>
#include <stdio.h>
void func(void) {
  const char *file_format = "%s/.config";
  size_t len;
  char *filepathname;
  struct passwd *pwd;

  /* Get /etc/passwd entry for current user */
  pwd = getpwuid(getuid());
  if (pwd == NULL) {
    /* Handle error */
  }

  /* Build full path name home dir from pw entry */

  len = strlen(pwd->pw_dir) + strlen(file_format) + 1;
  pathname = (char *)malloc(len);
  if (NULL == filepathname) {
    /* Handle error */
  }
  int r = snprintf(pathname, len, file_format, pwd->pw_dir);
  if (r < 0 || r >= len) {
    /* Handle error */
  }
  if (unlink(pathname) != 0) {
    /* Handle error */
  }

  free(pathname);
}