/**************************************************************************** * libs/libc/stdio/lib_fopen.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include "libc.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* Open mode flags */ #define MODE_R (1 << 0) /* Bit 0: "r{b|x|+}" open for reading */ #define MODE_W (1 << 1) /* Bit 1: "w{b|x|+}" open for writing, truncating, * or creating file */ #define MODE_A (1 << 2) /* Bit 2: "a{b|x|+}" open for writing, appending * the to file */ #define MODE_PLUS (1 << 3) /* Bit 3: "{r|w|a|b|x}+" open for update (reading * and writing) */ #define MODE_B (1 << 4) /* Bit 4: "{r|w|a|x|+}b" Binary mode */ #define MODE_X (1 << 5) /* Bit 5: "{r|w|a|b|+}x" Open exclusive mode */ #define MODE_T (1 << 6) /* Bit 6: "{r|w|a|+}t" Text mode */ #define MODE_NONE 0 /* No access mode determined */ #define MODE_MASK (MODE_R | MODE_W | MODE_A) /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: fdopen ****************************************************************************/ FAR FILE *fdopen(int fd, FAR const char *mode) { FAR FILE *filep = NULL; int oflags; int ret; /* Map the open mode string to open flags */ oflags = lib_mode2oflags(mode); if (oflags >= 0) { ret = fs_fdopen(fd, oflags, NULL, &filep); if (ret < 0) { set_errno(-ret); } } return filep; } /**************************************************************************** * Name: fopen ****************************************************************************/ FAR FILE *fopen(FAR const char *path, FAR const char *mode) { FAR FILE *filep = NULL; int oflags; int fd; int ret; /* Map the open mode string to open flags */ oflags = lib_mode2oflags(mode); if (oflags < 0) { return NULL; } /* Open the file */ fd = open(path, oflags, 0666); /* If the open was successful, then call fdopen() using the file * descriptor returned by open. If open failed, then just return the * NULL stream -- open() has already set the errno. */ if (fd >= 0) { ret = fs_fdopen(fd, oflags, NULL, &filep); if (ret < 0) { /* Don't forget to close the file descriptor if any other * failures are reported by fdopen(). */ close(fd); set_errno(-ret); filep = NULL; } } return filep; } /**************************************************************************** * Name: lib_mode2oflags ****************************************************************************/ int lib_mode2oflags(FAR const char *mode) { unsigned int state; int oflags; /* Verify that a mode string was provided. */ DEBUGASSERT(mode); /* Parse the mode string to determine the corresponding open flags */ state = MODE_NONE; oflags = 0; for (; *mode; mode++) { switch (*mode) { /* Open for read access ("r{b|x|+}") */ case 'r' : if (state == MODE_NONE) { /* Open for read access */ oflags = O_RDOK; state = MODE_R; } else { goto errout; } break; /* Open for write access ("w{b|x|+}") */ case 'w' : if (state == MODE_NONE) { /* Open for write access, truncating any existing file */ oflags = (O_WROK | O_CREAT | O_TRUNC); state = MODE_W; } else { goto errout; } break; /* Open for write/append access ("a{b|x|+}") */ case 'a' : if (state == MODE_NONE) { /* Write to the end of the file */ oflags = O_WROK | O_CREAT | O_APPEND; state = MODE_A; } else { goto errout; } break; /* Open for update access ("{r|w|a|b|x}+") */ case '+' : switch (state & MODE_MASK) { case MODE_R: { /* Retain any binary and exclusive mode selections */ oflags &= (O_BINARY | O_EXCL); /* Open for read/write access */ oflags |= O_RDWR; state |= MODE_PLUS; } break; case MODE_W: { /* Retain any binary and exclusive mode selections */ oflags &= (O_BINARY | O_EXCL); /* Open for write read/access, truncating any existing * file. */ oflags |= (O_RDWR | O_CREAT | O_TRUNC); state |= MODE_PLUS; } break; case MODE_A: { /* Retain any binary and exclusive mode selections */ oflags &= (O_BINARY | O_EXCL); /* Read from the beginning of the file; write to the * end, */ oflags |= (O_RDWR | O_CREAT | O_APPEND); state |= MODE_PLUS; } break; default: goto errout; break; } break; /* Open for binary access ("{r|w|a|x|+}b") */ case 'b' : if ((state & MODE_MASK) != MODE_NONE) { /* The file is opened in binary mode */ oflags |= O_BINARY; state |= MODE_B; } else { goto errout; } break; /* Open for exclusive access ("{r|w|a|b|+}x") */ case 'X' : if ((state & MODE_MASK) != MODE_NONE) { /* The file is opened in exclusive mode */ oflags |= O_EXCL; state |= MODE_X; } else { goto errout; } break; /* Open for text (translated) access ("{r|w|a|x|+}t") */ case 't' : if ((state & MODE_MASK) != MODE_NONE) { /* The file is opened in text mode */ oflags |= O_TEXT; state |= MODE_T; } else { goto errout; } break; /* Unrecognized or unsupported mode */ default: goto errout; break; } } return oflags; /* Both fopen and fdopen should fail with errno == EINVAL if the mode * string is invalid. */ errout: set_errno(EINVAL); return ERROR; }