diff options
Diffstat (limited to '')
| -rw-r--r-- | include/unistd.h | 74 | ||||
| -rw-r--r-- | src/unistd/exec.c | 50 | ||||
| -rw-r--r-- | src/unistd/searchpath.c | 55 | ||||
| -rw-r--r-- | src/unistd/searchpath2.c | 132 |
4 files changed, 264 insertions, 47 deletions
diff --git a/include/unistd.h b/include/unistd.h index 47db049..d27f342 100644 --- a/include/unistd.h +++ b/include/unistd.h @@ -800,6 +800,80 @@ int fexecv(int, char* const[]); */ int fexecve(int, char* const[], char* const[]); +#if defined(__PLAN9_SOURCE) || defined(__SLIBC_SOURCE) +/** + * Search the environment variable $PATH for an executable + * file whose name is the specified name. Slashes are ignored + * and treated as any other character. $PATH is searched + * for left to right, and ':' is used as the path-delimiter. + * + * $PATH is not inspected if `name` starts with './', '../', or '/'. + * + * This is a Plan 9 from Bell Labs compliant slibc extension. + * + * @etymology (Search) ($PATH) for an executable. + * + * @param name The name of the sought executable. Must not be `NULL`. + * @return The pathname of the sought file, `NULL` on error, + * or if not found. Files that are not executable + * are (almost) ignored. + * + * @throws ENOMEM The process cannot allocate enough memory. + * @throws ENOENT $PATH is not defined, there are no directories + * listed in $PATH, or the sought file is not + * exist inside $PATH. + * @throws EACCES None of the candidates (with at least one candidate) + * are executable by the current user. + * @throws Any exception defined for access(3), except for `EROFS`, + * these when encountered, the search is aborted, unless + * the error is `ENOENT` or `EACCES`. + * + * @since Always. + */ +char* searchpath(const char*); +#endif + +#if defined(__SLIBC_SOURCE) +/** + * Search the environment variable $PATH for an executable + * file whose name is the specified name. Slashes are ignored + * and treated as any other character. $PATH is searched + * for left to right, and ':' is used as the path-delimiter. + * If $PATH is not defined, a fallback value for $PATH will be + * used. + * + * $PATH is not inspected if `name` starts with './', '../', or '/'. + * + * This function was added because it was useful in implementing + * the `exec`-function family. + * + * This is a slibc extension. + * + * @etymology Variant of (searchpath) that takes (2) arguments. + * + * @param name The name of the sought executable. Must not be `NULL`. + * @param fallback Value to use instead of the value of $PATH, if + * path is not defined. If `NULL` the fall rules for + * the `exec`-functions are used: The current working + * directory, and the default value for $PATH. + * @return The pathname of the sought file, `NULL` on error, + * or if not found. Files that are not executable + * are (almost) ignored. + * + * @throws ENOMEM The process cannot allocate enough memory. + * @throws ENOENT There are no directories listed in $PATH, or + * the sought file is not exist inside $PATH. + * @throws EACCES None of the candidates (with at least one candidate) + * are executable by the current user. + * @throws Any exception defined for access(3), except for `EROFS`, + * these when encountered, the search is aborted, unless + * the error is `ENOENT` or `EACCES`. + * + * @since Always. + */ +char* searchpath2(const char*, const char*); +#endif + #endif diff --git a/src/unistd/exec.c b/src/unistd/exec.c index c6e4fca..9375baa 100644 --- a/src/unistd/exec.c +++ b/src/unistd/exec.c @@ -21,9 +21,6 @@ #include <alloca.h> #include <string.h> #include <stdlib.h> -/* TODO temporary contants from other headers { */ -#define _CS_PATH 1 -/* } */ @@ -323,12 +320,7 @@ int execve(const char* path, char* const argv[], char* const envp[]) */ int execvpe(const char* file, char* const argv[], char* const envp[]) { - char* path = NULL; char* pathname = NULL; - char* p; - char* q; - size_t len = 0; - int eacces = 0; int saved_errno; if (strchr(file, '/')) @@ -337,49 +329,13 @@ int execvpe(const char* file, char* const argv[], char* const envp[]) if (!*file) return errno = ENOENT, -1; - path = getenv("PATH"); - if (path == NULL) - { - if ((len = confstr(_CS_PATH, NULL, 0))) - { - path = malloc((2 + len) * sizeof(char)); - if (path == NULL) - goto fail; - if (!confstr(_CS_PATH, stpcpy(path, ".:"), len)) - free(path), path = NULL; - } - if (path == NULL) - path = strdup(".:/usr/local/bin:/bin:/usr/bin"); - } - else - path = strdup(path); - if (path == NULL) - goto fail; - - pathname = malloc((strlen(path) + strlen(file) + 2) * sizeof(char)); + pathname = searchpath2(file, NULL); if (pathname == NULL) - goto fail; - - for (p = path; *p; p = q + 1) - { - if (p == (q = strchr(p, ':'))) - continue; - *q = '\0'; - - stpcpy(stpcpy(stpcpy(pathname, p), "/"), file); - - execve(pathname, argv, envp); - if (errno == EACCES) eacces = 1; - else if (errno != ENOENT) goto fail; - } + return -1; - free(path); - free(pathname); - return errno = (eacces ? EACCES : ENOENT), -1; + execve(pathname, argv, envp); - fail: saved_errno = errno; - free(path); free(pathname); errno = saved_errno; return -1; diff --git a/src/unistd/searchpath.c b/src/unistd/searchpath.c new file mode 100644 index 0000000..84bc58e --- /dev/null +++ b/src/unistd/searchpath.c @@ -0,0 +1,55 @@ +/** + * slibc — Yet another C library + * Copyright © 2015 Mattias Andrée (maandree@member.fsf.org) + * + * 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 <unistd.h> + + + +/** + * Search the environment variable $PATH for an executable + * file whose name is the specified name. Slashes are ignored + * and treated as any other character. $PATH is searched + * for left to right, and ':' is used as the path-delimiter. + * + * $PATH is not inspected if `name` starts with './', '../', or '/'. + * + * This is a Plan 9 from Bell Labs compliant slibc extension. + * + * @etymology (Search) ($PATH) for an executable. + * + * @param name The name of the sought executable. + * @return The pathname of the sought file, `NULL` on error, + * or if not found. Files that are not executable + * are (almost) ignored. + * + * @throws ENOMEM The process cannot allocate enough memory. + * @throws ENOENT $PATH is not defined, there are no directories + * listed in $PATH, or the sought file is not + * exist inside $PATH. + * @throws EACCES None of the candidates (with at least one candidate) + * are executable by the current user. + * @throws Any exception defined for access(3), except for `EROFS`, + * these when encountered, the search is aborted, unless + * the error is `ENOENT` or `EACCES`. + * + * @since Always. + */ +char* searchpath(const char* name) +{ + return searchpath2(name, ""); +} + diff --git a/src/unistd/searchpath2.c b/src/unistd/searchpath2.c new file mode 100644 index 0000000..9921550 --- /dev/null +++ b/src/unistd/searchpath2.c @@ -0,0 +1,132 @@ +/** + * slibc — Yet another C library + * Copyright © 2015 Mattias Andrée (maandree@member.fsf.org) + * + * 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 <unistd.h> +#include <stdlib.h> +#include <string.h> +/* TODO temporary contants from other headers { */ +#define _CS_PATH 1 +/* } */ + + + +/** + * Search the environment variable $PATH for an executable + * file whose name is the specified name. Slashes are ignored + * and treated as any other character. $PATH is searched + * for left to right, and ':' is used as the path-delimiter. + * If $PATH is not defined, a fallback value for $PATH will be + * used. + * + * $PATH is not inspected if `name` starts with './', '../', or '/'. + * + * This function was added because it was useful in implementing + * the `exec`-function family. + * + * This is a slibc extension. + * + * @etymology Variant of (searchpath) that takes (2) arguments. + * + * @param name The name of the sought executable. Must not be `NULL`. + * @param fallback Value to use instead of the value of $PATH, if + * path is not defined. If `NULL` the fall rules for + * the `exec`-functions are used: The current working + * directory, and the default value for $PATH. + * @return The pathname of the sought file, `NULL` on error, + * or if not found. Files that are not executable + * are (almost) ignored. + * + * @throws ENOMEM The process cannot allocate enough memory. + * @throws ENOENT There are no directories listed in $PATH, or + * the sought file is not exist inside $PATH. + * @throws EACCES None of the candidates (with at least one candidate) + * are executable by the current user. + * @throws Any exception defined for access(3), except for `EROFS`, + * these when encountered, the search is aborted, unless + * the error is `ENOENT` or `EACCES`. + * + * @since Always. + */ +char* searchpath2(const char* name, const char* fallback) +{ + char* path; + size_t len = 0; + char* pathname = NULL; + char* p; + char* q; + int eacces = 0; + int saved_errno; + + if (strstarts(name, "./") || strstarts(name, "../") || strstarts(name, "/")) + { + if (access(name, X_OK) == 0) + return strdup(name); + return NULL; + } + + path = getenv("PATH"); + if ((path == NULL) && (fallback == NULL)) + { + if ((len = confstr(_CS_PATH, NULL, 0))) + { + path = malloc((2 + len) * sizeof(char)); + if (path == NULL) + goto fail; + if (!confstr(_CS_PATH, stpcpy(path, ".:"), len)) + free(path), path = NULL; + } + if (path == NULL) + path = strdup(".:/usr/local/bin:/bin:/usr/bin"); + } + else + path = strdup(path == NULL ? fallback : path); + if (path == NULL) + goto fail; + + pathname = malloc((strlen(path) + strlen(name) + 2) * sizeof(char)); + if (pathname == NULL) + goto fail; + + for (p = path; *p; p = q + 1) + { + if (p == (q = strchr(p, ':'))) + continue; + *q = '\0'; + + stpcpy(stpcpy(stpcpy(pathname, p), "/"), name); + + if (access(pathname, X_OK) == 0) + { + char* truncated = realloc(pathname, (strlen(pathname) + 1) * sizeof(char)); + return truncated == NULL ? pathname : truncated; + } + else if (errno == EACCES) eacces = 1; + else if (errno != ENOENT) goto fail; + } + + free(path); + free(pathname); + return errno = (eacces ? EACCES : ENOENT), -1; + + fail: + saved_errno = errno; + free(path); + free(pathname); + errno = saved_errno; + return -1; +} + |