diff options
Diffstat (limited to 'src/path.c')
| -rw-r--r-- | src/path.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/src/path.c b/src/path.c new file mode 100644 index 0000000..278200b --- /dev/null +++ b/src/path.c @@ -0,0 +1,205 @@ +/* GNU m4 -- A simple macro processor + + Copyright (C) 1989-1993, 2004, 2006-2013 Free Software Foundation, + Inc. + + This file is part of GNU M4. + + GNU M4 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. + + GNU M4 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/>. +*/ + +/* Handling of path search of included files via the builtins "include" + and "sinclude". */ + +#include "m4.h" + +struct includes +{ + struct includes *next; /* next directory to search */ + const char *dir; /* directory */ + int len; +}; + +typedef struct includes includes; + +static includes *dir_list; /* the list of path directories */ +static includes *dir_list_end; /* the end of same */ +static int dir_max_length; /* length of longest directory name */ + + +void +include_init (void) +{ + dir_list = NULL; + dir_list_end = NULL; + dir_max_length = 0; +} + +void +include_env_init (void) +{ + char *path; + char *path_end; + char *env_path; + + if (no_gnu_extensions) + return; + + env_path = getenv ("M4PATH"); + if (env_path == NULL) + return; + + env_path = xstrdup (env_path); + path = env_path; + + do + { + path_end = strchr (path, ':'); + if (path_end) + *path_end = '\0'; + add_include_directory (path); + path = path_end + 1; + } + while (path_end); + free (env_path); +} + +void +add_include_directory (const char *dir) +{ + includes *incl; + + if (no_gnu_extensions) + return; + + if (*dir == '\0') + dir = "."; + + incl = (includes *) xmalloc (sizeof (struct includes)); + incl->next = NULL; + incl->len = strlen (dir); + incl->dir = xstrdup (dir); + + if (incl->len > dir_max_length) /* remember len of longest directory */ + dir_max_length = incl->len; + + if (dir_list_end == NULL) + dir_list = incl; + else + dir_list_end->next = incl; + dir_list_end = incl; + +#ifdef DEBUG_INCL + xfprintf (stderr, "add_include_directory (%s);\n", dir); +#endif +} + +/* Attempt to open FILE; if it opens, verify that it is not a + directory, and ensure it does not leak across execs. */ +static FILE * +m4_fopen (const char *file) +{ + FILE *fp = fopen (file, "r"); + if (fp) + { + struct stat st; + int fd = fileno (fp); + if (fstat (fd, &st) == 0 && S_ISDIR (st.st_mode)) + { + fclose (fp); + errno = EISDIR; + return NULL; + } + if (set_cloexec_flag (fd, true) != 0) + M4ERROR ((warning_status, errno, + "Warning: cannot protect input file across forks")); + } + return fp; +} + +/* Search for FILE, first in `.', then according to -I options. If + successful, return the open file, and if RESULT is not NULL, set + *RESULT to a malloc'd string that represents the file found with + respect to the current working directory. */ + +FILE * +m4_path_search (const char *file, char **result) +{ + FILE *fp; + includes *incl; + char *name; /* buffer for constructed name */ + int e; + + if (result) + *result = NULL; + + /* Reject empty file. */ + if (!*file) + { + errno = ENOENT; + return NULL; + } + + /* Look in current working directory first. */ + fp = m4_fopen (file); + if (fp != NULL) + { + if (result) + *result = xstrdup (file); + return fp; + } + + /* If file not found, and filename absolute, fail. */ + if (IS_ABSOLUTE_FILE_NAME (file) || no_gnu_extensions) + return NULL; + e = errno; + + for (incl = dir_list; incl != NULL; incl = incl->next) + { + name = file_name_concat (incl->dir, file, NULL); + +#ifdef DEBUG_INCL + xfprintf (stderr, "m4_path_search (%s) -- trying %s\n", file, name); +#endif + + fp = m4_fopen (name); + if (fp != NULL) + { + if (debug_level & DEBUG_TRACE_PATH) + DEBUG_MESSAGE2 ("path search for `%s' found `%s'", file, name); + if (result) + *result = name; + else + free (name); + return fp; + } + free (name); + } + errno = e; + return fp; +} + +#ifdef DEBUG_INCL + +static void M4_GNUC_UNUSED +include_dump (void) +{ + includes *incl; + + xfprintf (stderr, "include_dump:\n"); + for (incl = dir_list; incl != NULL; incl = incl->next) + xfprintf (stderr, "\t%s\n", incl->dir); +} + +#endif /* DEBUG_INCL */ |