view lib/portability.c @ 1604:f057223498e4 draft

Remove more strncpy() calls. The semantics of strncat() and strncpy() are non-obvious, so let's not use 'em. Both zero all their remaining buffer space, and with strncat() the size is the space left at the _end_ of the string (not the size of the buffer) so it's way too easy to stomp memory you don't own. As long as we have to measure stuff ourselves to get it right, just use memcpy().
author Rob Landley <rob@landley.net>
date Sat, 13 Dec 2014 11:56:41 -0600
parents ce22ad7a26c1
children aafd2f28245a
line wrap: on
line source

/* portability.c - code to workaround the deficiencies of various platforms.
 *
 * Copyright 2012 Rob Landley <rob@landley.net>
 * Copyright 2012 Georgi Chorbadzhiyski <gf@unixsol.org>
 */

#include "toys.h"

#if !defined(__uClinux__)
pid_t xfork(void)
{
  pid_t pid = fork();

  if (pid < 0) perror_exit("fork");

  return pid;
}
#endif

#if defined(__APPLE__)
ssize_t getdelim(char **linep, size_t *np, int delim, FILE *stream)
{
  int ch;
  size_t new_len;
  ssize_t i = 0;
  char *line, *new_line;

  // Invalid input
  if (!linep || !np) {
    errno = EINVAL;
    return -1;
  }

  if (*linep == NULL || *np == 0) {
    *np = 1024;
    *linep = calloc(1, *np);
    if (*linep == NULL) return -1;
  }
  line = *linep;

  while ((ch = getc(stream)) != EOF) {
    if (i > *np) {
      // Need more space
      new_len = *np + 1024;
      new_line = realloc(*linep, new_len);
      if (!new_line) return -1;
      *np = new_len;
      *linep = new_line;
    }

    line[i] = ch;
    if (ch == delim) break;
    i += 1;
  }

  if (i > *np) {
    // Need more space
    new_len  = i + 2;
    new_line = realloc(*linep, new_len);
    if (!new_line) return -1;
    *np = new_len;
    *linep = new_line;
  }
  line[i + 1] = '\0';

  return i > 0 ? i : -1;
}

ssize_t getline(char **linep, size_t *np, FILE *stream)
{
  return getdelim(linep, np, '\n', stream);
}

extern char **environ;

int clearenv(void)
{
  *environ = NULL;
  return 0;
}
#endif