mergerfs/libfuse/lib/fuse_opt.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU LGPLv2.
  See the file COPYING.LIB
*/

#include "fuse_opt.h"

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

struct fuse_opt_context
{
  void *data;
  const struct fuse_opt *opt;
  fuse_opt_proc_t proc;
  int argctr;
  int argc;
  char **argv;
  struct fuse_args outargs;
  char *opts;
  int nonopt;
};

void
fuse_opt_free_args(struct fuse_args *args)
{
  if (args) {
    if (args->argv && args->allocated) {
      int i;
      for (i = 0; i < args->argc; i++)
        free(args->argv[i]);
      free(args->argv);
    }
    args->argc = 0;
    args->argv = NULL;
    args->allocated = 0;
  }
}

static
int
alloc_failed(void)
{
  fprintf(stderr, "fuse: memory allocation failed\n");
  return -1;
}

int
fuse_opt_add_arg(struct fuse_args *args, const char *arg)
{
  char **newargv;
  char *newarg;

  assert(!args->argv || args->allocated);

  newarg = strdup(arg);
  if (!newarg)
    return alloc_failed();

  newargv = realloc(args->argv, (args->argc + 2) * sizeof(char *));
  if (!newargv) {
    free(newarg);
    return alloc_failed();
  }

  args->argv = newargv;
  args->allocated = 1;
  args->argv[args->argc++] = newarg;
  args->argv[args->argc] = NULL;
  return 0;
}

static int fuse_opt_insert_arg_common(struct fuse_args *args, int pos,
				      const char *arg)
{
  assert(pos <= args->argc);
  if (fuse_opt_add_arg(args, arg) == -1)
    return -1;

  if (pos != args->argc - 1) {
    char *newarg = args->argv[args->argc - 1];
    memmove(&args->argv[pos + 1], &args->argv[pos],
            sizeof(char *) * (args->argc - pos - 1));
    args->argv[pos] = newarg;
  }
  return 0;
}

int fuse_opt_insert_arg(struct fuse_args *args, int pos, const char *arg)
{
  return fuse_opt_insert_arg_common(args, pos, arg);
}

static int next_arg(struct fuse_opt_context *ctx, const char *opt)
{
  if (ctx->argctr + 1 >= ctx->argc) {
    fprintf(stderr, "fuse: missing argument after `%s'\n", opt);
    return -1;
  }
  ctx->argctr++;
  return 0;
}

static int add_arg(struct fuse_opt_context *ctx, const char *arg)
{
  return fuse_opt_add_arg(&ctx->outargs, arg);
}

static int add_opt_common(char **opts, const char *opt, int esc)
{
  unsigned oldlen = *opts ? strlen(*opts) : 0;
  char *d = realloc(*opts, oldlen + 1 + strlen(opt) * 2 + 1);

  if (!d)
    return alloc_failed();

  *opts = d;
  if (oldlen) {
    d += oldlen;
    *d++ = ',';
  }

  for (; *opt; opt++) {
    if (esc && (*opt == ',' || *opt == '\\'))
      *d++ = '\\';
    *d++ = *opt;
  }
  *d = '\0';

  return 0;
}

int fuse_opt_add_opt(char **opts, const char *opt)
{
  return add_opt_common(opts, opt, 0);
}

int fuse_opt_add_opt_escaped(char **opts, const char *opt)
{
  return add_opt_common(opts, opt, 1);
}

static int add_opt(struct fuse_opt_context *ctx, const char *opt)
{
  return add_opt_common(&ctx->opts, opt, 1);
}

static int call_proc(struct fuse_opt_context *ctx, const char *arg, int key,
		     int iso)
{
  if (key == FUSE_OPT_KEY_DISCARD)
    return 0;

  if (key != FUSE_OPT_KEY_KEEP && ctx->proc) {
    int res = ctx->proc(ctx->data, arg, key, &ctx->outargs);
    if (res == -1 || !res)
      return res;
  }
  if (iso)
    return add_opt(ctx, arg);
  else
    return add_arg(ctx, arg);
}

static int match_template(const char *t, const char *arg, unsigned *sepp)
{
  int arglen = strlen(arg);
  const char *sep = strchr(t, '=');
  sep = sep ? sep : strchr(t, ' ');
  if (sep && (!sep[1] || sep[1] == '%')) {
    int tlen = sep - t;
    if (sep[0] == '=')
      tlen ++;
    if (arglen >= tlen && strncmp(arg, t, tlen) == 0) {
      *sepp = sep - t;
      return 1;
    }
  }
  if (strcmp(t, arg) == 0) {
    *sepp = 0;
    return 1;
  }
  return 0;
}

static const struct fuse_opt *find_opt(const struct fuse_opt *opt,
				       const char *arg, unsigned *sepp)
{
  for (; opt && opt->templ; opt++)
    if (match_template(opt->templ, arg, sepp))
      return opt;
  return NULL;
}

int fuse_opt_match(const struct fuse_opt *opts, const char *opt)
{
  unsigned dummy;
  return find_opt(opts, opt, &dummy) ? 1 : 0;
}

static int process_opt_param(void *var, const char *format, const char *param,
			     const char *arg)
{
  assert(format[0] == '%');
  if (format[1] == 's') {
    char *copy = strdup(param);
    if (!copy)
      return alloc_failed();

    *(char **) var = copy;
  } else {
    if (sscanf(param, format, var) != 1) {
      fprintf(stderr, "fuse: invalid parameter in option `%s'\n", arg);
      return -1;
    }
  }
  return 0;
}

static int process_opt(struct fuse_opt_context *ctx,
		       const struct fuse_opt *opt, unsigned sep,
		       const char *arg, int iso)
{
  if (opt->offset == -1U) {
    if (call_proc(ctx, arg, opt->value, iso) == -1)
      return -1;
  } else {
    void *var = ctx->data + opt->offset;
    if (sep && opt->templ[sep + 1]) {
      const char *param = arg + sep;
      if (opt->templ[sep] == '=')
        param ++;
      if (process_opt_param(var, opt->templ + sep + 1,
                            param, arg) == -1)
        return -1;
    } else
      *(int *)var = opt->value;
  }
  return 0;
}

static int process_opt_sep_arg(struct fuse_opt_context *ctx,
			       const struct fuse_opt *opt, unsigned sep,
			       const char *arg, int iso)
{
  int res;
  char *newarg;
  char *param;

  if (next_arg(ctx, arg) == -1)
    return -1;

  param = ctx->argv[ctx->argctr];
  newarg = malloc(sep + strlen(param) + 1);
  if (!newarg)
    return alloc_failed();

  memcpy(newarg, arg, sep);
  strcpy(newarg + sep, param);
  res = process_opt(ctx, opt, sep, newarg, iso);
  free(newarg);

  return res;
}

static int process_gopt(struct fuse_opt_context *ctx, const char *arg, int iso)
{
  unsigned sep;
  const struct fuse_opt *opt = find_opt(ctx->opt, arg, &sep);
  if (opt) {
    for (; opt; opt = find_opt(opt + 1, arg, &sep)) {
      int res;
      if (sep && opt->templ[sep] == ' ' && !arg[sep])
        res = process_opt_sep_arg(ctx, opt, sep, arg,
                                  iso);
      else
        res = process_opt(ctx, opt, sep, arg, iso);
      if (res == -1)
        return -1;
    }
    return 0;
  } else
    return call_proc(ctx, arg, FUSE_OPT_KEY_OPT, iso);
}

static int process_real_option_group(struct fuse_opt_context *ctx, char *opts)
{
  char *s = opts;
  char *d = s;
  int end = 0;

  while (!end) {
    if (*s == '\0')
      end = 1;
    if (*s == ',' || end) {
      int res;

      *d = '\0';
      res = process_gopt(ctx, opts, 1);
      if (res == -1)
        return -1;
      d = opts;
    } else {
      if (s[0] == '\\' && s[1] != '\0') {
        s++;
        if (s[0] >= '0' && s[0] <= '3' &&
            s[1] >= '0' && s[1] <= '7' &&
            s[2] >= '0' && s[2] <= '7') {
          *d++ = (s[0] - '0') * 0100 +
            (s[1] - '0') * 0010 +
            (s[2] - '0');
          s += 2;
        } else {
          *d++ = *s;
        }
      } else {
        *d++ = *s;
      }
    }
    s++;
  }

  return 0;
}

static int process_option_group(struct fuse_opt_context *ctx, const char *opts)
{
  int res;
  char *copy = strdup(opts);

  if (!copy) {
    fprintf(stderr, "fuse: memory allocation failed\n");
    return -1;
  }
  res = process_real_option_group(ctx, copy);
  free(copy);
  return res;
}

static int process_one(struct fuse_opt_context *ctx, const char *arg)
{
  if (ctx->nonopt || arg[0] != '-')
    return call_proc(ctx, arg, FUSE_OPT_KEY_NONOPT, 0);
  else if (arg[1] == 'o') {
    if (arg[2])
      return process_option_group(ctx, arg + 2);
    else {
      if (next_arg(ctx, arg) == -1)
        return -1;

      return process_option_group(ctx,
                                  ctx->argv[ctx->argctr]);
    }
  } else if (arg[1] == '-' && !arg[2]) {
    if (add_arg(ctx, arg) == -1)
      return -1;
    ctx->nonopt = ctx->outargs.argc;
    return 0;
  } else
    return process_gopt(ctx, arg, 0);
}

static int opt_parse(struct fuse_opt_context *ctx)
{
  if (ctx->argc) {
    if (add_arg(ctx, ctx->argv[0]) == -1)
      return -1;
  }

  for (ctx->argctr = 1; ctx->argctr < ctx->argc; ctx->argctr++)
    if (process_one(ctx, ctx->argv[ctx->argctr]) == -1)
      return -1;

  if (ctx->opts) {
    if (fuse_opt_insert_arg(&ctx->outargs, 1, "-o") == -1 ||
        fuse_opt_insert_arg(&ctx->outargs, 2, ctx->opts) == -1)
      return -1;
  }

  /* If option separator ("--") is the last argument, remove it */
  if (ctx->nonopt && ctx->nonopt == ctx->outargs.argc &&
      strcmp(ctx->outargs.argv[ctx->outargs.argc - 1], "--") == 0) {
    free(ctx->outargs.argv[ctx->outargs.argc - 1]);
    ctx->outargs.argv[--ctx->outargs.argc] = NULL;
  }

  return 0;
}

int fuse_opt_parse(struct fuse_args *args, void *data,
		   const struct fuse_opt opts[], fuse_opt_proc_t proc)
{
  int res;
  struct fuse_opt_context ctx = {
    .data = data,
    .opt = opts,
    .proc = proc,
  };

  if (!args || !args->argv || !args->argc)
    return 0;

  ctx.argc = args->argc;
  ctx.argv = args->argv;

  res = opt_parse(&ctx);
  if (res != -1) {
    struct fuse_args tmp = *args;
    *args = ctx.outargs;
    ctx.outargs = tmp;
  }
  free(ctx.opts);
  fuse_opt_free_args(&ctx.outargs);
  return res;
}