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Diffstat (limited to '')
| -rw-r--r-- | tilde.c | 493 |
1 files changed, 493 insertions, 0 deletions
@@ -0,0 +1,493 @@ +/* tilde.c -- Tilde expansion code (~/foo := $HOME/foo). */ + +/* Copyright (C) 1988-2020 Free Software Foundation, Inc. + + This file is part of the GNU Readline Library (Readline), a library + for reading lines of text with interactive input and history editing. + + Readline 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. + + Readline 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 Readline. If not, see <http://www.gnu.org/licenses/>. +*/ + +#if defined (HAVE_CONFIG_H) +# include <config.h> +#endif + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include <sys/types.h> +# endif +# include <unistd.h> +#endif + +#if defined (HAVE_STRING_H) +# include <string.h> +#else /* !HAVE_STRING_H */ +# include <strings.h> +#endif /* !HAVE_STRING_H */ + +#if defined (HAVE_STDLIB_H) +# include <stdlib.h> +#else +# include "ansi_stdlib.h" +#endif /* HAVE_STDLIB_H */ + +#include <sys/types.h> +#if defined (HAVE_PWD_H) +#include <pwd.h> +#endif + +#include "tilde.h" + +#if defined (TEST) || defined (STATIC_MALLOC) +static void *xmalloc (), *xrealloc (); +#else +# include "xmalloc.h" +#endif /* TEST || STATIC_MALLOC */ + +#if !defined (HAVE_GETPW_DECLS) +# if defined (HAVE_GETPWUID) +extern struct passwd *getpwuid (uid_t); +# endif +# if defined (HAVE_GETPWNAM) +extern struct passwd *getpwnam (const char *); +# endif +#endif /* !HAVE_GETPW_DECLS */ + +#if !defined (savestring) +#define savestring(x) strcpy ((char *)xmalloc (1 + strlen (x)), (x)) +#endif /* !savestring */ + +#if !defined (NULL) +# if defined (__STDC__) +# define NULL ((void *) 0) +# else +# define NULL 0x0 +# endif /* !__STDC__ */ +#endif /* !NULL */ + +/* If being compiled as part of bash, these will be satisfied from + variables.o. If being compiled as part of readline, they will + be satisfied from shell.o. */ +extern char *sh_get_home_dir (void); +extern char *sh_get_env_value (const char *); + +/* The default value of tilde_additional_prefixes. This is set to + whitespace preceding a tilde so that simple programs which do not + perform any word separation get desired behaviour. */ +static const char *default_prefixes[] = + { " ~", "\t~", (const char *)NULL }; + +/* The default value of tilde_additional_suffixes. This is set to + whitespace or newline so that simple programs which do not + perform any word separation get desired behaviour. */ +static const char *default_suffixes[] = + { " ", "\n", (const char *)NULL }; + +/* If non-null, this contains the address of a function that the application + wants called before trying the standard tilde expansions. The function + is called with the text sans tilde, and returns a malloc()'ed string + which is the expansion, or a NULL pointer if the expansion fails. */ +tilde_hook_func_t *tilde_expansion_preexpansion_hook = (tilde_hook_func_t *)NULL; + +/* If non-null, this contains the address of a function to call if the + standard meaning for expanding a tilde fails. The function is called + with the text (sans tilde, as in "foo"), and returns a malloc()'ed string + which is the expansion, or a NULL pointer if there is no expansion. */ +tilde_hook_func_t *tilde_expansion_failure_hook = (tilde_hook_func_t *)NULL; + +/* When non-null, this is a NULL terminated array of strings which + are duplicates for a tilde prefix. Bash uses this to expand + `=~' and `:~'. */ +char **tilde_additional_prefixes = (char **)default_prefixes; + +/* When non-null, this is a NULL terminated array of strings which match + the end of a username, instead of just "/". Bash sets this to + `:' and `=~'. */ +char **tilde_additional_suffixes = (char **)default_suffixes; + +static int tilde_find_prefix (const char *, int *); +static int tilde_find_suffix (const char *); +static char *isolate_tilde_prefix (const char *, int *); +static char *glue_prefix_and_suffix (char *, const char *, int); + +/* Find the start of a tilde expansion in STRING, and return the index of + the tilde which starts the expansion. Place the length of the text + which identified this tilde starter in LEN, excluding the tilde itself. */ +static int +tilde_find_prefix (const char *string, int *len) +{ + register int i, j, string_len; + register char **prefixes; + + prefixes = tilde_additional_prefixes; + + string_len = strlen (string); + *len = 0; + + if (*string == '\0' || *string == '~') + return (0); + + if (prefixes) + { + for (i = 0; i < string_len; i++) + { + for (j = 0; prefixes[j]; j++) + { + if (strncmp (string + i, prefixes[j], strlen (prefixes[j])) == 0) + { + *len = strlen (prefixes[j]) - 1; + return (i + *len); + } + } + } + } + return (string_len); +} + +/* Find the end of a tilde expansion in STRING, and return the index of + the character which ends the tilde definition. */ +static int +tilde_find_suffix (const char *string) +{ + register int i, j, string_len; + register char **suffixes; + + suffixes = tilde_additional_suffixes; + string_len = strlen (string); + + for (i = 0; i < string_len; i++) + { +#if defined (__MSDOS__) + if (string[i] == '/' || string[i] == '\\' /* || !string[i] */) +#else + if (string[i] == '/' /* || !string[i] */) +#endif + break; + + for (j = 0; suffixes && suffixes[j]; j++) + { + if (strncmp (string + i, suffixes[j], strlen (suffixes[j])) == 0) + return (i); + } + } + return (i); +} + +/* Return a new string which is the result of tilde expanding STRING. */ +char * +tilde_expand (const char *string) +{ + char *result; + int result_size, result_index; + + result_index = result_size = 0; + if (result = strchr (string, '~')) + result = (char *)xmalloc (result_size = (strlen (string) + 16)); + else + result = (char *)xmalloc (result_size = (strlen (string) + 1)); + + /* Scan through STRING expanding tildes as we come to them. */ + while (1) + { + register int start, end; + char *tilde_word, *expansion; + int len; + + /* Make START point to the tilde which starts the expansion. */ + start = tilde_find_prefix (string, &len); + + /* Copy the skipped text into the result. */ + if ((result_index + start + 1) > result_size) + result = (char *)xrealloc (result, 1 + (result_size += (start + 20))); + + strncpy (result + result_index, string, start); + result_index += start; + + /* Advance STRING to the starting tilde. */ + string += start; + + /* Make END be the index of one after the last character of the + username. */ + end = tilde_find_suffix (string); + + /* If both START and END are zero, we are all done. */ + if (!start && !end) + break; + + /* Expand the entire tilde word, and copy it into RESULT. */ + tilde_word = (char *)xmalloc (1 + end); + strncpy (tilde_word, string, end); + tilde_word[end] = '\0'; + string += end; + + expansion = tilde_expand_word (tilde_word); + + if (expansion == 0) + expansion = tilde_word; + else + xfree (tilde_word); + + len = strlen (expansion); +#ifdef __CYGWIN__ + /* Fix for Cygwin to prevent ~user/xxx from expanding to //xxx when + $HOME for `user' is /. On cygwin, // denotes a network drive. */ + if (len > 1 || *expansion != '/' || *string != '/') +#endif + { + if ((result_index + len + 1) > result_size) + result = (char *)xrealloc (result, 1 + (result_size += (len + 20))); + + strcpy (result + result_index, expansion); + result_index += len; + } + xfree (expansion); + } + + result[result_index] = '\0'; + + return (result); +} + +/* Take FNAME and return the tilde prefix we want expanded. If LENP is + non-null, the index of the end of the prefix into FNAME is returned in + the location it points to. */ +static char * +isolate_tilde_prefix (const char *fname, int *lenp) +{ + char *ret; + int i; + + ret = (char *)xmalloc (strlen (fname)); +#if defined (__MSDOS__) + for (i = 1; fname[i] && fname[i] != '/' && fname[i] != '\\'; i++) +#else + for (i = 1; fname[i] && fname[i] != '/'; i++) +#endif + ret[i - 1] = fname[i]; + ret[i - 1] = '\0'; + if (lenp) + *lenp = i; + return ret; +} + +#if 0 +/* Public function to scan a string (FNAME) beginning with a tilde and find + the portion of the string that should be passed to the tilde expansion + function. Right now, it just calls tilde_find_suffix and allocates new + memory, but it can be expanded to do different things later. */ +char * +tilde_find_word (const char *fname, int flags, int *lenp) +{ + int x; + char *r; + + x = tilde_find_suffix (fname); + if (x == 0) + { + r = savestring (fname); + if (lenp) + *lenp = 0; + } + else + { + r = (char *)xmalloc (1 + x); + strncpy (r, fname, x); + r[x] = '\0'; + if (lenp) + *lenp = x; + } + + return r; +} +#endif + +/* Return a string that is PREFIX concatenated with SUFFIX starting at + SUFFIND. */ +static char * +glue_prefix_and_suffix (char *prefix, const char *suffix, int suffind) +{ + char *ret; + int plen, slen; + + plen = (prefix && *prefix) ? strlen (prefix) : 0; + slen = strlen (suffix + suffind); + ret = (char *)xmalloc (plen + slen + 1); + if (plen) + strcpy (ret, prefix); + strcpy (ret + plen, suffix + suffind); + return ret; +} + +/* Do the work of tilde expansion on FILENAME. FILENAME starts with a + tilde. If there is no expansion, call tilde_expansion_failure_hook. + This always returns a newly-allocated string, never static storage. */ +char * +tilde_expand_word (const char *filename) +{ + char *dirname, *expansion, *username; + int user_len; + struct passwd *user_entry; + + if (filename == 0) + return ((char *)NULL); + + if (*filename != '~') + return (savestring (filename)); + + /* A leading `~/' or a bare `~' is *always* translated to the value of + $HOME or the home directory of the current user, regardless of any + preexpansion hook. */ + if (filename[1] == '\0' || filename[1] == '/') + { + /* Prefix $HOME to the rest of the string. */ + expansion = sh_get_env_value ("HOME"); +#if defined (_WIN32) + if (expansion == 0) + expansion = sh_get_env_value ("APPDATA"); +#endif + + /* If there is no HOME variable, look up the directory in + the password database. */ + if (expansion == 0) + expansion = sh_get_home_dir (); + + return (glue_prefix_and_suffix (expansion, filename, 1)); + } + + username = isolate_tilde_prefix (filename, &user_len); + + if (tilde_expansion_preexpansion_hook) + { + expansion = (*tilde_expansion_preexpansion_hook) (username); + if (expansion) + { + dirname = glue_prefix_and_suffix (expansion, filename, user_len); + xfree (username); + xfree (expansion); + return (dirname); + } + } + + /* No preexpansion hook, or the preexpansion hook failed. Look in the + password database. */ + dirname = (char *)NULL; +#if defined (HAVE_GETPWNAM) + user_entry = getpwnam (username); +#else + user_entry = 0; +#endif + if (user_entry == 0) + { + /* If the calling program has a special syntax for expanding tildes, + and we couldn't find a standard expansion, then let them try. */ + if (tilde_expansion_failure_hook) + { + expansion = (*tilde_expansion_failure_hook) (username); + if (expansion) + { + dirname = glue_prefix_and_suffix (expansion, filename, user_len); + xfree (expansion); + } + } + /* If we don't have a failure hook, or if the failure hook did not + expand the tilde, return a copy of what we were passed. */ + if (dirname == 0) + dirname = savestring (filename); + } +#if defined (HAVE_GETPWENT) + else + dirname = glue_prefix_and_suffix (user_entry->pw_dir, filename, user_len); +#endif + + xfree (username); +#if defined (HAVE_GETPWENT) + endpwent (); +#endif + return (dirname); +} + + +#if defined (TEST) +#undef NULL +#include <stdio.h> + +main (int argc, char **argv) +{ + char *result, line[512]; + int done = 0; + + while (!done) + { + printf ("~expand: "); + fflush (stdout); + + if (!gets (line)) + strcpy (line, "done"); + + if ((strcmp (line, "done") == 0) || + (strcmp (line, "quit") == 0) || + (strcmp (line, "exit") == 0)) + { + done = 1; + break; + } + + result = tilde_expand (line); + printf (" --> %s\n", result); + free (result); + } + exit (0); +} + +static void memory_error_and_abort (void); + +static void * +xmalloc (size_t bytes) +{ + void *temp = (char *)malloc (bytes); + + if (!temp) + memory_error_and_abort (); + return (temp); +} + +static void * +xrealloc (void *pointer, int bytes) +{ + void *temp; + + if (!pointer) + temp = malloc (bytes); + else + temp = realloc (pointer, bytes); + + if (!temp) + memory_error_and_abort (); + + return (temp); +} + +static void +memory_error_and_abort (void) +{ + fprintf (stderr, "readline: out of virtual memory\n"); + abort (); +} + +/* + * Local variables: + * compile-command: "gcc -g -DTEST -o tilde tilde.c" + * end: + */ +#endif /* TEST */ |