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authorMattias Andrée <maandree@operamail.com>2015-10-11 02:57:00 +0200
committerMattias Andrée <maandree@operamail.com>2015-10-11 03:14:47 +0200
commitb844dc8037d30914ceef5b9e01d77662f462a299 (patch)
tree1da5cf7393ca90b334dc582e67068a5d4a4e68fe
parentfix m error (diff)
downloadslibc-b844dc8037d30914ceef5b9e01d77662f462a299.tar.gz
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add execat functions
Signed-off-by: Mattias Andrée <maandree@operamail.com>
-rw-r--r--include/unistd.h315
-rw-r--r--src/unistd/execat.c507
2 files changed, 818 insertions, 4 deletions
diff --git a/include/unistd.h b/include/unistd.h
index a783f57..33a3db0 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -190,7 +190,7 @@ int execlp(const char*, ... /*, NULL */)
* As a slibc extension, it can be empty.
* This list shall be terminated by a `NULL` sentinel.
* @param envp The list of environment variables the new program shall
- * have set. Each element shall be foramtted $name=$value.
+ * have set. Each element shall be formatted $name=$value.
* This list shall be `NULL`-terminated. The behaviour
* is system-dependant if this argument is `NULL`.
* @return This function does not return on success,
@@ -218,7 +218,7 @@ int execle(const char*, ... /*, NULL, char* const[] */)
* As a slibc extension, it can be empty.
* This list shall be terminated by a `NULL` sentinel.
* @param envp The list of environment variables the new program shall
- * have set. Each element shall be foramtted $name=$value.
+ * have set. Each element shall be formatted $name=$value.
* This list shall be `NULL`-terminated. The behaviour
* is system-dependant if this argument is `NULL`.
* @return This function does not return on success,
@@ -290,7 +290,7 @@ int execvp(const char*, char* const[])
* be `NULL`-terminated. The behaviour is
* system-dependant if this argument is `NULL`.
* @param envp The list of environment variables the new program shall
- * have set. Each element shall be foramtted $name=$value.
+ * have set. Each element shall be formatted $name=$value.
* This list shall be `NULL`-terminated. The behaviour
* is system-dependant if this argument is `NULL`.
* @return This function does not return on success,
@@ -322,7 +322,7 @@ int execve(const char*, char* const[], char* const[])
* be `NULL`-terminated. The behaviour is
* system-dependant if this argument is `NULL`.
* @param envp The list of environment variables the new program shall
- * have set. Each element shall be foramtted $name=$value.
+ * have set. Each element shall be formatted $name=$value.
* This list shall be `NULL`-terminated. The behaviour
* is system-dependant if this argument is `NULL`.
* @return This function does not return on success,
@@ -336,6 +336,313 @@ int execvpe(const char*, char* const[], char* const[])
#endif
+#if defined(_SLIBC_SOURCE) && !defined(__PORTABLE)
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param path The pathname of the file to execute.
+ * @param ... The arguments with which to execute the file.
+ * The arguments should have the type `const char*`.
+ * As a slibc extension, it can be empty.
+ * This list shall be terminated by a `NULL` sentinel.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `path` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `path` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execlat(int, const char*, ... /*, NULL, int */)
+ __GCC_ONLY(__attribute__((sentinel(1), nonnull(2))));
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param file The pathname of the file to execute,
+ * or the filename of a file in $PATH,
+ * to execute. If $PATH is not set, the current
+ * working directory (yes, you read that right,)
+ * and a default value for $PATH will be used.
+ * @param ... The arguments with which to execute the file.
+ * The arguments should have the type `const char*`.
+ * As a slibc extension, it can be empty.
+ * This list shall be terminated by a `NULL` sentinel.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `file` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `file` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execlpat(int, const char*, ... /*, NULL, int */)
+ __GCC_ONLY(__attribute__((sentinel(1), nonnull(2))));
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param path The pathname of the file to execute.
+ * @param ... The arguments with which to execute the file.
+ * The arguments should have the type `const char*`.
+ * As a slibc extension, it can be empty.
+ * This list shall be terminated by a `NULL` sentinel.
+ * @param envp The list of environment variables the new program shall
+ * have set. Each element shall be formatted $name=$value.
+ * This list shall be `NULL`-terminated. The behaviour
+ * is system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `path` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `path` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execleat(int, const char*, ... /*, NULL, char* const[], int */)
+ __GCC_ONLY(__attribute__((sentinel(2), nonnull(2))));
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param file The pathname of the file to execute,
+ * or the filename of a file in $PATH,
+ * to execute. If $PATH is not set, the current
+ * working directory (yes, you read that right,)
+ * and a default value for $PATH will be used.
+ * @param ... The arguments with which to execute the file.
+ * The arguments should have the type `const char*`.
+ * As a slibc extension, it can be empty.
+ * This list shall be terminated by a `NULL` sentinel.
+ * @param envp The list of environment variables the new program shall
+ * have set. Each element shall be formatted $name=$value.
+ * This list shall be `NULL`-terminated. The behaviour
+ * is system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `file` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `file` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execlpeat(int, const char*, ... /*, NULL, char* const[], int */)
+ __GCC_ONLY(__attribute__((sentinel(2), nonnull(2))));
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param path The pathname of the file to execute.
+ * @param argv The arguments with which to execute the file.
+ * This parameter should really have the type
+ * `const char* const[]`, but that probably not
+ * so because compiles take issue with casts
+ * adding const to any pointer in the type
+ * except the outmost pointer. This list shall
+ * be `NULL`-terminated. The behaviour is
+ * system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `path` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `path` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execvat(int, const char*, char* const[], int)
+ __GCC_ONLY(__attribute__((nonnull(2))));
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param file The pathname of the file to execute,
+ * or the filename of a file in $PATH,
+ * to execute. If $PATH is not set, the current
+ * working directory (yes, you read that right,)
+ * and a default value for $PATH will be used.
+ * @param argv The arguments with which to execute the file.
+ * This parameter should really have the type
+ * `const char* const[]`, but that probably not
+ * so because compiles take issue with casts
+ * adding const to any pointer in the type
+ * except the outmost pointer. This list shall
+ * be `NULL`-terminated. The behaviour is
+ * system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `file` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `file` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execvpat(int, const char*, char* const[], int)
+ __GCC_ONLY(__attribute__((nonnull(2))));
+#endif
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param path The pathname of the file to execute.
+ * @param argv The arguments with which to execute the file.
+ * This parameter should really have the type
+ * `const char* const[]`, but that probably not
+ * so because compiles take issue with casts
+ * adding const to any pointer in the type
+ * except the outmost pointer. This list shall
+ * be `NULL`-terminated. The behaviour is
+ * system-dependant if this argument is `NULL`.
+ * @param envp The list of environment variables the new program shall
+ * have set. Each element shall be formatted $name=$value.
+ * This list shall be `NULL`-terminated. The behaviour
+ * is system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `path` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `path` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execveat(int, const char*, char* const[], char* const[], int)
+ __GCC_ONLY(__attribute__((nonnull(2))));
+
+#if defined(_SLIBC_SOURCE) && !defined(__PORTABLE)
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param file The pathname of the file to execute,
+ * or the filename of a file in $PATH,
+ * to execute. If $PATH is not set, the current
+ * working directory (yes, you read that right,)
+ * and a default value for $PATH will be used.
+ * @param argv The arguments with which to execute the file.
+ * This parameter should really have the type
+ * `const char* const[]`, but that probably not
+ * so because compiles take issue with casts
+ * adding const to any pointer in the type
+ * except the outmost pointer. This list shall
+ * be `NULL`-terminated. The behaviour is
+ * system-dependant if this argument is `NULL`.
+ * @param envp The list of environment variables the new program shall
+ * have set. Each element shall be formatted $name=$value.
+ * This list shall be `NULL`-terminated. The behaviour
+ * is system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `file` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `file` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execvpeat(int, const char*, char* const[], char* const[], int)
+ __GCC_ONLY(__attribute__((nonnull(2))));
+#endif
+
+
#endif
diff --git a/src/unistd/execat.c b/src/unistd/execat.c
new file mode 100644
index 0000000..d80d24b
--- /dev/null
+++ b/src/unistd/execat.c
@@ -0,0 +1,507 @@
+/**
+ * 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 <stdarg.h>
+#include <errno.h>
+#include <alloca.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+
+
+/**
+ * The current environment variables.
+ */
+extern char** environ;
+
+
+
+/**
+ * Common code for the `execl*at` functions.
+ *
+ * @param dirfd The first argument of said functions.
+ * @param file The second argument of said functions.
+ * @param argv The rest of the arguments of said functions;
+ * may conclude `envp`.
+ * @param fetch_envp Whether `argv` includes `envp`.
+ * @param use_path Whether $PATH may be used.
+ *
+ * @throws Any error specified for execve(2).
+ */
+static void vexecat(int dirfd, const char* file, va_list argv, int fetch_envp, int use_path)
+{
+ char* const* envp = environ;
+ size_t n = 0, i;
+ va_list args;
+ char** argv_;
+ int flags;
+
+ va_copy(args, argv);
+ while (n++, va_arg(args, char*) != NULL)
+ break;
+
+ if (fetch_envp)
+ envp = va_arg(args, char* const*);
+ flags = va_arg(args, int);
+
+ argv_ = alloca(n * sizeof(char*));
+ for (i = 0; i < n; i++)
+ argv_[i] = va_arg(argv, char*);
+
+ (void)(use_path ? execvpeat : execveat)(dirfd, file, argv_, envp, flags);
+}
+
+
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param path The pathname of the file to execute.
+ * @param ... The arguments with which to execute the file.
+ * The arguments should have the type `const char*`.
+ * As a slibc extension, it can be empty.
+ * This list shall be terminated by a `NULL` sentinel.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `path` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `path` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execlat(int dirfd, const char* path, ... /*, NULL, int flags */)
+{
+ int saved_errno;
+ va_list argv;
+ va_start(argv, path);
+ vexecat(dirfd, path, argv, 0, 0);
+ saved_errno = errno;
+ va_end(argv);
+ return errno = saved_errno, -1;
+}
+
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param file The pathname of the file to execute,
+ * or the filename of a file in $PATH,
+ * to execute. If $PATH is not set, the current
+ * working directory (yes, you read that right,)
+ * and a default value for $PATH will be used.
+ * @param ... The arguments with which to execute the file.
+ * The arguments should have the type `const char*`.
+ * As a slibc extension, it can be empty.
+ * This list shall be terminated by a `NULL` sentinel.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `file` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `file` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execlpat(int dirfd, const char* file, ... /*, NULL, int flags */)
+{
+ int saved_errno;
+ va_list argv;
+ va_start(argv, path);
+ vexecat(dirfd, path, argv, 0, 1);
+ saved_errno = errno;
+ va_end(argv);
+ return errno = saved_errno, -1;
+}
+
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param path The pathname of the file to execute.
+ * @param ... The arguments with which to execute the file.
+ * The arguments should have the type `const char*`.
+ * As a slibc extension, it can be empty.
+ * This list shall be terminated by a `NULL` sentinel.
+ * @param envp The list of environment variables the new program shall
+ * have set. Each element shall be formatted $name=$value.
+ * This list shall be `NULL`-terminated. The behaviour
+ * is system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `path` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `path` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execleat(int dirfd, const char* path, ... /*, NULL, char* const[] envp, int flags */)
+{
+ int saved_errno;
+ va_list argv;
+ va_start(argv, path);
+ vexecat(dirfd, path, argv, 1, 0);
+ saved_errno = errno;
+ va_end(argv);
+ return errno = saved_errno, -1;
+}
+
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param file The pathname of the file to execute,
+ * or the filename of a file in $PATH,
+ * to execute. If $PATH is not set, the current
+ * working directory (yes, you read that right,)
+ * and a default value for $PATH will be used.
+ * @param ... The arguments with which to execute the file.
+ * The arguments should have the type `const char*`.
+ * As a slibc extension, it can be empty.
+ * This list shall be terminated by a `NULL` sentinel.
+ * @param envp The list of environment variables the new program shall
+ * have set. Each element shall be formatted $name=$value.
+ * This list shall be `NULL`-terminated. The behaviour
+ * is system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `file` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `file` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execlpeat(int dirfd, const char* file, ... /*, NULL, char* const[] envp, int flags */)
+{
+ int saved_errno;
+ va_list argv;
+ va_start(argv, path);
+ vexecat(dirfd, path, argv, 1, 1);
+ saved_errno = errno;
+ va_end(argv);
+ return errno = saved_errno, -1;
+}
+
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param path The pathname of the file to execute.
+ * @param argv The arguments with which to execute the file.
+ * This parameter should really have the type
+ * `const char* const[]`, but that probably not
+ * so because compiles take issue with casts
+ * adding const to any pointer in the type
+ * except the outmost pointer. This list shall
+ * be `NULL`-terminated. The behaviour is
+ * system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `path` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `path` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execvat(int dirfd, const char* path, char* const argv[], int flags)
+{
+ return execveat(dirfd, path, argv, environ, flags);
+}
+
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param file The pathname of the file to execute,
+ * or the filename of a file in $PATH,
+ * to execute. If $PATH is not set, the current
+ * working directory (yes, you read that right,)
+ * and a default value for $PATH will be used.
+ * @param argv The arguments with which to execute the file.
+ * This parameter should really have the type
+ * `const char* const[]`, but that probably not
+ * so because compiles take issue with casts
+ * adding const to any pointer in the type
+ * except the outmost pointer. This list shall
+ * be `NULL`-terminated. The behaviour is
+ * system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `file` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `file` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execvpat(int dirfd, const char* file, char* const argv[], int flags)
+{
+ return execvpe(dirfd, path, argv, environ, flags);
+}
+
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param path The pathname of the file to execute.
+ * @param argv The arguments with which to execute the file.
+ * This parameter should really have the type
+ * `const char* const[]`, but that probably not
+ * so because compiles take issue with casts
+ * adding const to any pointer in the type
+ * except the outmost pointer. This list shall
+ * be `NULL`-terminated. The behaviour is
+ * system-dependant if this argument is `NULL`.
+ * @param envp The list of environment variables the new program shall
+ * have set. Each element shall be formatted $name=$value.
+ * This list shall be `NULL`-terminated. The behaviour
+ * is system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `path` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `path` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execveat(int dirfd, const char* path, char* const argv[], char* const envp[], int flags)
+{
+/* TODO use linux system call if available */
+ struct stat attr;
+ char* pathname;
+
+ if (*path == '/')
+ return execve(path, argv, envp);
+
+ if ((dirfd == AT_FDCWD) && (flags & AT_EMPTY_PATH) && !*path)
+ return errno = EISDIR, -1;
+
+ if ((dirfd == AT_FDCWD) && (flags & AT_SYMLINK_NOFOLLOW))
+ {
+ if (lstat(path, &attr))
+ return -1;
+ if (S_IFLNK(attr.st_mode))
+ return errno = ELOOP, -1;
+ }
+
+ pathname = malloc(sizeof("/dev/fd//") + (3 * sizeof(int) + strlen(path)) * sizeof(char));
+ if (pathname == NULL)
+ return -1;
+
+ sprintf(pathname, "/dev/fd/%i%s%s", dirfd, *path ? "/" : "", path);
+ return execve(pathname, argv, envp);
+}
+
+
+/**
+ * Replace the current process image with a new process image.
+ *
+ * This is a slibc extension.
+ *
+ * @param dirfd File descriptor for a directory (opened with
+ * with the open(2) `O_PATH` flag,) that will
+ * act as the current working directory.
+ * If `AT_FDCWD`, the current working directory
+ * will be used.
+ * @param file The pathname of the file to execute,
+ * or the filename of a file in $PATH,
+ * to execute. If $PATH is not set, the current
+ * working directory (yes, you read that right,)
+ * and a default value for $PATH will be used.
+ * @param argv The arguments with which to execute the file.
+ * This parameter should really have the type
+ * `const char* const[]`, but that probably not
+ * so because compiles take issue with casts
+ * adding const to any pointer in the type
+ * except the outmost pointer. This list shall
+ * be `NULL`-terminated. The behaviour is
+ * system-dependant if this argument is `NULL`.
+ * @param envp The list of environment variables the new program shall
+ * have set. Each element shall be formatted $name=$value.
+ * This list shall be `NULL`-terminated. The behaviour
+ * is system-dependant if this argument is `NULL`.
+ * @param flags Bit mask that can include zero or more of the
+ * following flags:
+ * AT_EMPTY_PATH:
+ * If `file` is an empty string, operate on the
+ * file (not directory) referred to by `dirfd`.
+ * AT_SYMLINK_NOFOLLOW:
+ * If `file` is relative is a symbolic link,
+ * fail with `errno` set to `ELOOP`.
+ * @return This function does not return on success,
+ * on error, -1 is returned and `errno` is
+ * set to describe the error.
+ *
+ * @throws Any error specified for execveat(2).
+ */
+int execvpeat(int dirfd, const char* file, char* const argv[], char* const envp[], int flags)
+{
+ char* path = NULL;
+ char* pathname = NULL;
+ char* p;
+ char* q;
+ size_t len = 0;
+ int eacces = 0;
+ int saved_errno;
+
+ if (strchr(file, '/') || !*file)
+ return execveat(dirfd, file, argv, envp, flags);
+
+ if (!*file)
+ return errno = ENOENT, -1;
+
+ path = getenv(PATH);
+ if (path == NULL)
+ {
+ execveat(dirfd, file, argv, envp, flags);
+ if (errno == EACCES) eacces = 1;
+ else if (errno != ENOENT) goto fail;
+
+ if ((len = confstr(_CS_PATH, NULL, 0)))
+ {
+ path = malloc(len * sizeof(char));
+ if (path == NULL)
+ goto fail;
+ if (!confstr(_CS_PATH, 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));
+ 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;
+ }
+
+ free(path);
+ free(pathname);
+ return errno = (eaccess ? EACCES : ENOENT), -1;
+
+ fail:
+ saved_errno = errno;
+ free(path);
+ free(pathname);
+ errno = saved_errno;
+ return -1;
+}
+