| /**************************************************************************** |
| * apps/fsutils/passwd/passwd_delete.c |
| * |
| * Copyright (C) 2016 Gregory Nutt. All rights reserved. |
| * Author: Gregory Nutt <gnutt@nuttx.org> |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * 3. Neither the name NuttX nor the names of its contributors may be |
| * used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| * |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Included Files |
| ****************************************************************************/ |
| |
| #include <nuttx/config.h> |
| |
| #include <sys/types.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <assert.h> |
| #include <errno.h> |
| |
| #include "passwd.h" |
| |
| /**************************************************************************** |
| * Private Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: passwd_copyfile |
| * |
| * Description: |
| * Copy copysize from instream to outstream (or until an error or EOF is |
| * encountered) |
| * |
| * Input Parameters: |
| * |
| * Returned Value: |
| * Zero (OK) is returned on success; a negated errno value is returned on |
| * failure. |
| * |
| ****************************************************************************/ |
| |
| static int passwd_copyfile(FAR char *iobuffer, FILE *instream, |
| FILE *outstream, size_t copysize) |
| { |
| FAR char *buffer; |
| ssize_t nxfrd; |
| size_t nwritten; |
| size_t nread; |
| size_t nbytes; |
| size_t gulpsize; |
| size_t ncopied; |
| size_t remaining; |
| bool eof; |
| |
| /* Copy 'offset' bytes from the instream to the outstream */ |
| |
| for (ncopied = 0, remaining = copysize, eof = false; |
| ncopied < copysize && !eof; |
| ncopied += nwritten) |
| { |
| /* How big of a gulp can we take on this pass through the loop */ |
| |
| gulpsize = remaining; |
| if (gulpsize > CONFIG_FSUTILS_PASSWD_IOBUFFER_SIZE) |
| { |
| gulpsize = CONFIG_FSUTILS_PASSWD_IOBUFFER_SIZE; |
| } |
| |
| /* Read a buffer of data from the instream */ |
| |
| buffer = iobuffer; |
| nbytes = gulpsize; |
| nread = 0; |
| |
| do |
| { |
| nxfrd = fread(buffer, 1, nbytes, instream); |
| if (nxfrd == 0) |
| { |
| /* Zero is returned on either a read error or end-of-file */ |
| |
| if (ferror(instream)) |
| { |
| /* Read error */ |
| |
| int errcode = errno; |
| DEBUGASSERT(errcode > 0); |
| |
| if (errcode != EINTR) |
| { |
| return -errcode; |
| } |
| } |
| else |
| { |
| /* End of file encountered. |
| * |
| * This occurs normally when copying to the end-of-the file. |
| * In that case, the caller just sticks a huge number in for |
| * copysize and lets the end-of-file indication terminate the |
| * copy. |
| */ |
| |
| eof = true; |
| |
| /* Was anything buffered on this pass? */ |
| |
| if (nread == 0) |
| { |
| /* No.. then we can just return success now */ |
| |
| return OK; |
| } |
| } |
| } |
| else |
| { |
| DEBUGASSERT(nxfrd > 0); |
| |
| /* Update counters and pointers for successful read */ |
| |
| nread += nxfrd; |
| buffer += nxfrd; |
| nbytes -= nxfrd; |
| } |
| } |
| while (nread < gulpsize && !eof); |
| |
| /* Write the buffer of data to outstream */ |
| |
| buffer = iobuffer; |
| nbytes = nread; |
| nwritten = 0; |
| |
| do |
| { |
| nxfrd = fwrite(buffer, 1, nbytes, outstream); |
| if (nxfrd == 0) |
| { |
| /* Write error */ |
| |
| int errcode = errno; |
| DEBUGASSERT(errcode > 0); |
| |
| if (errcode != EINTR) |
| { |
| return -errcode; |
| } |
| } |
| else |
| { |
| DEBUGASSERT(nxfrd > 0); |
| |
| /* Update counters and pointers for successful write */ |
| |
| nwritten += nxfrd; |
| buffer += nxfrd; |
| nbytes -= nxfrd; |
| } |
| } |
| while (nwritten < nread); |
| |
| remaining -= nwritten; |
| } |
| |
| return OK; |
| } |
| |
| /**************************************************************************** |
| * Public Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: passwd_delete |
| * |
| * Description: |
| * Delete on record from the password file at offset. |
| * |
| * Input Parameters: |
| * |
| * Returned Value: |
| * Zero (OK) is returned on success; a negated errno value is returned on |
| * failure. |
| * |
| ****************************************************************************/ |
| |
| int passwd_delete(off_t offset) |
| { |
| FAR char *iobuffer; |
| FILE *instream; |
| FILE *outstream; |
| int ret; |
| |
| /* Allocate an I/O buffer for the transfer */ |
| |
| iobuffer = (FAR char *)malloc(CONFIG_FSUTILS_PASSWD_IOBUFFER_SIZE); |
| if (iobuffer == NULL) |
| { |
| return -ENOMEM; |
| } |
| |
| /* Rename the /set/password file */ |
| |
| ret = rename(CONFIG_FSUTILS_PASSWD_PATH, |
| CONFIG_FSUTILS_PASSWD_PATH ".tmp"); |
| if (ret < 0) |
| { |
| ret = -errno; |
| DEBUGASSERT(ret < 0); |
| goto errout_with_iobuffer; |
| } |
| |
| /* Open the renamed file for reading; re-create the /etc/passwd file for |
| * writing. |
| */ |
| |
| instream = fopen(CONFIG_FSUTILS_PASSWD_PATH ".tmp", "r"); |
| if (instream == NULL) |
| { |
| ret = -errno; |
| DEBUGASSERT(ret < 0); |
| goto errout_with_tmpfile; |
| } |
| |
| outstream = fopen(CONFIG_FSUTILS_PASSWD_PATH, "w"); |
| if (outstream == NULL) |
| { |
| ret = -errno; |
| DEBUGASSERT(ret < 0); |
| goto errout_with_instream; |
| } |
| |
| /* Copy 'offset' bytes from the renamed file to the original file */ |
| |
| ret = passwd_copyfile(iobuffer, instream, outstream, offset); |
| if (ret < 0) |
| { |
| goto errout_with_outstream; |
| } |
| |
| /* Now read from the instream and discard the current line */ |
| |
| for (; ; ) |
| { |
| int ch = fgetc(instream); |
| if (ch == EOF) |
| { |
| if (feof(instream)) |
| { |
| /* Could this really happen without encountering the |
| * newline terminator? |
| */ |
| |
| break; |
| } |
| else |
| { |
| ret = -errno; |
| DEBUGASSERT(ret < 0); |
| goto errout_with_instream; |
| } |
| } |
| else if (ch == '\n') |
| { |
| break; |
| } |
| } |
| |
| /* Copy the rest of the file */ |
| |
| ret = passwd_copyfile(iobuffer, instream, outstream, SIZE_MAX); |
| |
| errout_with_outstream: |
| (void)fclose(outstream); |
| |
| errout_with_instream: |
| (void)fclose(instream); |
| |
| errout_with_tmpfile: |
| if (ret < 0) |
| { |
| /* Restore the previous /etc/passwd file */ |
| |
| (void)unlink(CONFIG_FSUTILS_PASSWD_PATH); |
| (void)rename(CONFIG_FSUTILS_PASSWD_PATH ".tmp", |
| CONFIG_FSUTILS_PASSWD_PATH); |
| } |
| else |
| { |
| /* Delete the previous /etc/passwd file */ |
| |
| (void)unlink(CONFIG_FSUTILS_PASSWD_PATH ".tmp"); |
| } |
| |
| errout_with_iobuffer: |
| free(iobuffer); |
| return ret; |
| } |