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Diffstat (limited to 'arch/um/os-Linux/execvp.c')
| -rw-r--r-- | arch/um/os-Linux/execvp.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/arch/um/os-Linux/execvp.c b/arch/um/os-Linux/execvp.c new file mode 100644 index 00000000000..66e583a4031 --- /dev/null +++ b/arch/um/os-Linux/execvp.c @@ -0,0 +1,149 @@ +/* Copyright (C) 2006 by Paolo Giarrusso - modified from glibc' execvp.c. + Original copyright notice follows: + + Copyright (C) 1991,92,1995-99,2002,2004 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 <stdbool.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <limits.h> + +#ifndef TEST +#include "um_malloc.h" +#else +#include <stdio.h> +#define um_kmalloc malloc +#endif +#include "os.h" + +/* Execute FILE, searching in the `PATH' environment variable if it contains + no slashes, with arguments ARGV and environment from `environ'. */ +int execvp_noalloc(char *buf, const char *file, char *const argv[]) +{ + if (*file == '\0') { + return -ENOENT; + } + + if (strchr (file, '/') != NULL) { + /* Don't search when it contains a slash. */ + execv(file, argv); + } else { + int got_eacces; + size_t len, pathlen; + char *name, *p; + char *path = getenv("PATH"); + if (path == NULL) + path = ":/bin:/usr/bin"; + + len = strlen(file) + 1; + pathlen = strlen(path); + /* Copy the file name at the top. */ + name = memcpy(buf + pathlen + 1, file, len); + /* And add the slash. */ + *--name = '/'; + + got_eacces = 0; + p = path; + do { + char *startp; + + path = p; + //Let's avoid this GNU extension. + //p = strchrnul (path, ':'); + p = strchr(path, ':'); + if (!p) + p = strchr(path, '\0'); + + 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 = memcpy(name - (p - path), path, p - path); + + /* Try to execute this name. If it works, execv will not return. */ + execv(startp, argv); + + /* + if (errno == ENOEXEC) { + } + */ + + 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 = 1; + 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. */ + case ENOEXEC: + /* We won't go searching for the shell + * if it is not executable - the Linux + * kernel already handles this enough, + * for us. */ + break; + + default: + /* Some other error means we found an executable file, but + something went wrong executing it; return the error to our + caller. */ + return -errno; + } + } 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. */ + return -EACCES; + } + + /* Return the error from the last attempt (probably ENOENT). */ + return -errno; +} +#ifdef TEST +int main(int argc, char**argv) +{ + char buf[PATH_MAX]; + int ret; + argc--; + if (!argc) { + fprintf(stderr, "Not enough arguments\n"); + return 1; + } + argv++; + if (ret = execvp_noalloc(buf, argv[0], argv)) { + errno = -ret; + perror("execvp_noalloc"); + } + return 0; +} +#endif |