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Diffstat (limited to 'libc/posix/execvp.c')
| -rw-r--r-- | libc/posix/execvp.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/libc/posix/execvp.c b/libc/posix/execvp.c new file mode 100644 index 000000000..8421bd048 --- /dev/null +++ b/libc/posix/execvp.c @@ -0,0 +1,198 @@ +/* Copyright (C) 1991,92,1995-99,2002,2004,2005 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <unistd.h> +#include <stdarg.h> +#include <stdbool.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <paths.h> + + +/* The file is accessible but it is not an executable file. Invoke + the shell to interpret it as a script. */ +static char ** +internal_function +allocate_scripts_argv (const char *file, char *const argv[]) +{ + /* Count the arguments. */ + int argc = 0; + while (argv[argc++]) + ; + + /* Construct an argument list for the shell. */ + char **new_argv = (char **) malloc ((argc + 1) * sizeof (char *)); + if (new_argv != NULL) + { + new_argv[0] = (char *) _PATH_BSHELL; + new_argv[1] = (char *) file; + while (argc > 1) + { + new_argv[argc] = argv[argc - 1]; + --argc; + } + } + + return new_argv; +} + + +/* Execute FILE, searching in the `PATH' environment variable if it contains + no slashes, with arguments ARGV and environment from `environ'. */ +int +execvp (file, argv) + const char *file; + char *const argv[]; +{ + if (*file == '\0') + { + /* We check the simple case first. */ + __set_errno (ENOENT); + return -1; + } + + char **script_argv = NULL; + + if (strchr (file, '/') != NULL) + { + /* Don't search when it contains a slash. */ + __execve (file, argv, __environ); + + if (errno == ENOEXEC) + { + script_argv = allocate_scripts_argv (file, argv); + if (script_argv != NULL) + { + __execve (script_argv[0], script_argv, __environ); + + free (script_argv); + } + } + } + else + { + char *path = getenv ("PATH"); + char *path_malloc = NULL; + if (path == NULL) + { + /* There is no `PATH' in the environment. + The default search path is the current directory + followed by the path `confstr' returns for `_CS_PATH'. */ + size_t len = confstr (_CS_PATH, (char *) NULL, 0); + path = (char *) malloc (1 + len); + if (path == NULL) + return -1; + path[0] = ':'; + (void) confstr (_CS_PATH, path + 1, len); + path_malloc = path; + } + + size_t len = strlen (file) + 1; + size_t pathlen = strlen (path); + char *name = malloc (pathlen + len + 1); + if (name == NULL) + { + free (path_malloc); + return -1; + } + /* Copy the file name at the top. */ + name = (char *) memcpy (name + pathlen + 1, file, len); + /* And add the slash. */ + *--name = '/'; + + bool got_eacces = false; + char *p = path; + do + { + char *startp; + + path = p; + p = __strchrnul (path, ':'); + + if (p == path) + /* Two adjacent colons, or a colon at the beginning or the end + of `PATH' means to search the current directory. */ + startp = name + 1; + else + startp = (char *) memcpy (name - (p - path), path, p - path); + + /* Try to execute this name. If it works, execve will not return. */ + __execve (startp, argv, __environ); + + if (errno == ENOEXEC) + { + if (script_argv == NULL) + { + script_argv = allocate_scripts_argv (startp, argv); + if (script_argv == NULL) + { + /* A possible EACCES error is not as important as + the ENOMEM. */ + got_eacces = false; + break; + } + } + + __execve (script_argv[0], script_argv, __environ); + } + + switch (errno) + { + case EACCES: + /* Record the we got a `Permission denied' error. If we end + up finding no executable we can use, we want to diagnose + that we did find one but were denied access. */ + got_eacces = true; + case ENOENT: + case ESTALE: + case ENOTDIR: + /* Those errors indicate the file is missing or not executable + by us, in which case we want to just try the next path + directory. */ + case ENODEV: + case ETIMEDOUT: + /* Some strange filesystems like AFS return even + stranger error numbers. They cannot reasonably mean + anything else so ignore those, too. */ + break; + + default: + /* Some other error means we found an executable file, but + something went wrong executing it; return the error to our + caller. */ + return -1; + } + } + while (*p++ != '\0'); + + /* We tried every element and none of them worked. */ + if (got_eacces) + /* At least one failure was due to permissions, so report that + error. */ + __set_errno (EACCES); + + free (script_argv); + free (name - pathlen); + free (path_malloc); + } + + /* Return the error from the last attempt (probably ENOENT). */ + return -1; +} +libc_hidden_def (execvp) |