cregit-Linux how code gets into the kernel

Release 4.14 arch/um/os-Linux/execvp.c

Directory: arch/um/os-Linux
/* 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; }

Contributors

PersonTokensPropCommitsCommitProp
Paolo 'Blaisorblade' Giarrusso282100.00%1100.00%
Total282100.00%1100.00%

#ifdef TEST
int main(int argc, char**argv) { char buf[PATH_MAX]; int ret; argc--; if (!argc) { os_warn("Not enough arguments\n"); return 1; } argv++; if (ret = execvp_noalloc(buf, argv[0], argv)) { errno = -ret; perror("execvp_noalloc"); } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Paolo 'Blaisorblade' Giarrusso7398.65%150.00%
Masami Hiramatsu11.35%150.00%
Total74100.00%2100.00%

#endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Paolo 'Blaisorblade' Giarrusso39899.25%133.33%
Al Viro20.50%133.33%
Masami Hiramatsu10.25%133.33%
Total401100.00%3100.00%
Directory: arch/um/os-Linux
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