smbd: Ignore twrp in chdir_below_conn()

[samba4-gss.git] / lib / util / util_file.c

/*
 * Unix SMB/CIFS implementation.
 * SMB parameters and setup
 * Copyright (C) Andrew Tridgell 1992-1998 Modified by Jeremy Allison 1995.
 *
 * Added afdgets() Jelmer Vernooij 2005
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 3 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "replace.h"
#include "system/shmem.h"
#include "system/filesys.h"
#include <talloc.h>
#include "lib/util/samba_util.h"
#include "lib/util/util_file.h"
#include "lib/util/sys_popen.h"
#include "lib/util/sys_rw.h"
#include "lib/util/debug.h"

/**
 * Read one line (data until next newline or eof) and allocate it
 */
_PUBLIC_ char *afdgets(int fd, TALLOC_CTX *mem_ctx, size_t hint)
{
        char *data = NULL;
        ssize_t alloc_size = 0, offset = 0, ret;
        int p;

        if (hint <= 0) hint = 0x100;

        do {
                alloc_size += hint;

                data = talloc_realloc(mem_ctx, data, char, alloc_size);

                if (!data)
                        return NULL;

                ret = read(fd, data + offset, hint);

                if (ret == 0) {
                        return NULL;
                }

                if (ret == -1) {
                        talloc_free(data);
                        return NULL;
                }

                /* Find newline */
                for (p = 0; p < ret; p++) {
                        if (data[offset + p] == '\n')
                                break;
                }

                if (p < ret) {
                        data[offset + p] = '\0';

                        /* Go back to position of newline */
                        lseek(fd, p - ret + 1, SEEK_CUR);
                        return data;
                }

                offset += ret;

        } while ((size_t)ret == hint);

        data[offset] = '\0';

        return data;
}

char *fgets_slash(TALLOC_CTX *mem_ctx, char *s2, size_t maxlen, FILE *f)
{
        char *s = s2;
        size_t len = 0;
        int c;
        bool start_of_line = true;

        if (feof(f)) {
                return NULL;
        }

        if (maxlen < 2) {
                return NULL;
        }

        if (s2 == NULL) {
                maxlen = MIN(maxlen,8);
                s = talloc_array(mem_ctx, char, maxlen);
        }

        if (s == NULL) {
                return NULL;
        }

        *s = 0;

        while (len < maxlen-1) {
                c = getc(f);
                switch (c)
                {
                    case '\r':
                            break;
                    case '\n':
                            while (len > 0 && s[len-1] == ' ') {
                                    s[--len] = 0;
                            }
                            if (len > 0 && s[len-1] == '\\') {
                                    s[--len] = 0;
                                    start_of_line = true;
                                    break;
                            }
                            return s;
                    case EOF:
                            if (len <= 0 && (s2 == NULL)) {
                                    TALLOC_FREE(s);
                            }
                            return (len>0) ? s : NULL;
                    case ' ':
                            if (start_of_line) {
                                    break;
                            }

                            FALL_THROUGH;
                    default:
                            start_of_line = false;
                            s[len++] = c;
                            s[len] = 0;
                }
                if ((s2 == NULL) && (len > maxlen-3)) {
                        size_t m;
                        char *t;

                        m = maxlen * 2;
                        if (m < maxlen) {
                                DBG_ERR("length overflow\n");
                                TALLOC_FREE(s);
                                return NULL;
                        }
                        maxlen = m;

                        t = talloc_realloc(mem_ctx, s, char, maxlen);
                        if (t == NULL) {
                                DBG_ERR("failed to expand buffer!\n");
                                TALLOC_FREE(s);
                                return NULL;
                        }

                        s = t;
                }
        }

        return s;
}

/**
load a file into memory from a fd.
**/
_PUBLIC_ char *fd_load(int fd, size_t *psize, size_t maxsize, TALLOC_CTX *mem_ctx)
{
        FILE *file;
        char *p = NULL;
        size_t size = 0;
        size_t chunk = 1024;
        int err;

        if (maxsize == 0) {
                maxsize = SIZE_MAX;
        }

        file = fdopen_keepfd(fd, "r");
        if (file == NULL) {
                return NULL;
        }

        while (size < maxsize) {
                size_t newbufsize;
                size_t nread;

                chunk = MIN(chunk, (maxsize - size));

                newbufsize = size + (chunk+1); /* chunk+1 can't overflow */
                if (newbufsize < size) {
                        goto fail; /* overflow */
                }

                p = talloc_realloc(mem_ctx, p, char, newbufsize);
                if (p == NULL) {
                        goto fail;
                }

                nread = fread(p+size, 1, chunk, file);
                size += nread;

                if (nread != chunk) {
                        break;
                }
        }

        err = ferror(file);
        if (err != 0) {
                goto fail;
        }

        p[size] = '\0';

        if (psize != NULL) {
                *psize = size;
        }

        fclose(file);
        return p;

fail:
        TALLOC_FREE(p);
        fclose(file);
        return NULL;
}

/**
load a file into memory
**/
_PUBLIC_ char *file_load(const char *fname, size_t *size, size_t maxsize, TALLOC_CTX *mem_ctx)
{
        int fd;
        char *p;

        if (!fname || !*fname) return NULL;

        fd = open(fname,O_RDONLY);
        if (fd == -1) return NULL;

        p = fd_load(fd, size, maxsize, mem_ctx);

        close(fd);

        return p;
}

/**
parse a buffer into lines
'p' will be freed on error, and otherwise will be made a child of the returned array
**/
static char **file_lines_parse_internal(char *p, size_t size, int *numlines, TALLOC_CTX *mem_ctx)
{
        unsigned int i;
        char *s, **ret;

        if (!p) return NULL;

        for (s = p, i=0; s < p+size; s++) {
                if (s[0] == '\n') i++;
        }

        ret = talloc_zero_array(mem_ctx, char *, i+2);
        if (!ret) {
                talloc_free(p);
                return NULL;
        }

        talloc_steal(ret, p);

        ret[0] = p;
        for (s = p, i=1; s < p+size; s++) {
                if (s[0] == '\n') {
                        s[0] = 0;
                        ret[i] = s+1;
                        i++;
                }
                if (s[0] == '\r') s[0] = 0;
        }

        /* remove any blank lines at the end */
        while (i > 0 && ret[i-1][0] == 0) {
                i--;
        }

        if (numlines) *numlines = i;

        return ret;
}


/**
load a file into memory and return an array of pointers to lines in the file
must be freed with talloc_free().
**/
_PUBLIC_ char **file_lines_load(const char *fname, int *numlines, size_t maxsize, TALLOC_CTX *mem_ctx)
{
        char *p;
        size_t size;

        p = file_load(fname, &size, maxsize, mem_ctx);
        if (!p) return NULL;

        return file_lines_parse_internal(p, size, numlines, mem_ctx);
}

/**
load a fd into memory and return an array of pointers to lines in the file
must be freed with talloc_free(). If convert is true calls unix_to_dos on
the list.
**/
_PUBLIC_ char **fd_lines_load(int fd, int *numlines, size_t maxsize, TALLOC_CTX *mem_ctx)
{
        char *p;
        size_t size;

        p = fd_load(fd, &size, maxsize, mem_ctx);
        if (!p) return NULL;

        return file_lines_parse_internal(p, size, numlines, mem_ctx);
}

_PUBLIC_ char **file_lines_parse(const char *p_in,
                        size_t size,
                        int *numlines,
                        TALLOC_CTX *mem_ctx)
{
        /*
         * Copy the incoming string so it can end up
         * being owned by the returned pointer and
         * freed when that is.
         */
        char *p = talloc_strdup(mem_ctx, p_in);
        if (p == NULL) {
                return NULL;
        }
        return file_lines_parse_internal(p, size, numlines, mem_ctx);
}

_PUBLIC_ bool file_save_mode(const char *fname, const void *packet,
                             size_t length, mode_t mode)
{
        ssize_t num_written;
        int fd;
        fd = open(fname, O_WRONLY|O_CREAT|O_EXCL, mode);
        if (fd == -1) {
                return false;
        }
        num_written = write(fd, packet, length);
        if (num_written == -1 || (size_t)num_written != length) {
                close(fd);
                return false;
        }
        close(fd);
        return true;
}

/**
  save a lump of data into a file. Mostly used for debugging
*/
_PUBLIC_ bool file_save(const char *fname, const void *packet, size_t length)
{
        return file_save_mode(fname, packet, length, 0644);
}

_PUBLIC_ int vfdprintf(int fd, const char *format, va_list ap)
{
        char *p;
        int len, ret;
        va_list ap2;

        va_copy(ap2, ap);
        len = vasprintf(&p, format, ap2);
        va_end(ap2);
        if (len <= 0) return len;
        ret = write(fd, p, len);
        SAFE_FREE(p);
        return ret;
}

_PUBLIC_ int fdprintf(int fd, const char *format, ...)
{
        va_list ap;
        int ret;

        va_start(ap, format);
        ret = vfdprintf(fd, format, ap);
        va_end(ap);
        return ret;
}


/*
  compare two files, return true if the two files have the same content
 */
bool file_compare(const char *path1, const char *path2)
{
        FILE *f1 = NULL, *f2 = NULL;
        uint8_t buf1[1024], buf2[1024];
        bool ret = false;

        f1 = fopen(path1, "r");
        if (f1 == NULL) {
                goto done;
        }
        f2 = fopen(path2, "r");
        if (f2 == NULL) {
                goto done;
        }

        while (!feof(f1)) {
                size_t n1 = fread(buf1, 1, sizeof(buf1), f1);
                size_t n2 = fread(buf2, 1, sizeof(buf2), f2);

                if (n1 != n2) {
                        goto done;
                }
                if (n1 == 0) {
                        ret = (feof(f1) && feof(f2));
                        goto done;
                }
                if (memcmp(buf1, buf2, n1) != 0) {
                        goto done;
                }
                if (n1 < sizeof(buf1)) {
                        bool has_error = (ferror(f1) || ferror(f2));
                        if (has_error) {
                                goto done;
                        }
                }
        }
        ret = true;
done:
        if (f2 != NULL) {
                fclose(f2);
        }
        if (f1 != NULL) {
                fclose(f1);
        }
        return ret;
}

/**
 Load from a pipe into memory.
**/
char *file_ploadv(char * const argl[], size_t *size)
{
        int fd, n;
        char *p = NULL;
        char buf[1024];
        size_t total;

        fd = sys_popenv(argl);
        if (fd == -1) {
                return NULL;
        }

        total = 0;

        while ((n = sys_read(fd, buf, sizeof(buf))) > 0) {
                p = talloc_realloc(NULL, p, char, total + n + 1);
                if (p == NULL) {
                        DBG_ERR("failed to expand buffer!\n");
                        close(fd);
                        return NULL;
                }
                memcpy(p+total, buf, n);
                total += n;
        }

        if (p != NULL) {
                p[total] = 0;
        }

        /*
         * FIXME: Perhaps ought to check that the command completed
         * successfully (returned 0); if not the data may be
         * truncated.
         */
        sys_pclose(fd);

        if (size) {
                *size = total;
        }

        return p;
}

/*
 * fopen a dup'ed fd. Prevent fclose to close the fd passed in.
 *
 * Don't use on fd's that have fcntl locks, on error it will close the
 * dup'ed fd, thus killing your fcntl locks.
 */
FILE *fdopen_keepfd(int fd, const char *mode)
{
        FILE *f = NULL;
        int dup_fd;

        dup_fd = dup(fd);
        if (dup_fd == -1) {
                return NULL;
        }

        f = fdopen(dup_fd, mode);
        if (f == NULL) {
                int err = errno;
                close(dup_fd);
                errno = err;
                return NULL;
        }

        return f;
}