Linux内核架构读书笔记 - 2.4.3 启动新线程

            1 *
2  * sys_execve() executes a new program.
3  */
4int do_execve(char * filename,
5char __user *__user *argv,
6char __user *__user *envp,
7struct pt_regs * regs)

             1
            /*
             2
             * Fill the binprm structure from the inode. 

             3
             * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes

             4
            */
             5
            int prepare_binprm(struct linux_binprm *bprm)
 6{
 7int mode;
 8struct inode * inode = bprm->file->f_path.dentry->d_inode;
 9int retval;
1011     mode = inode->i_mode;
12if (bprm->file->f_op == NULL)
13return -EACCES;
1415     bprm->e_uid = current->euid;
16     bprm->e_gid = current->egid;
1718if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
19/* Set-uid? */20if (mode & S_ISUID) {
21             current->personality &= ~PER_CLEAR_ON_SETID;
22             bprm->e_uid = inode->i_uid;
23        }
2425/* Set-gid? */26/*27         * If setgid is set but no group execute bit then this
28         * is a candidate for mandatory locking, not a setgid
29         * executable.
30*/31if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
32             current->personality &= ~PER_CLEAR_ON_SETID;
33             bprm->e_gid = inode->i_gid;
34        }
35    }
3637/* fill in binprm security blob */38     retval = security_bprm_set(bprm);
39if (retval)
40return retval;
4142     memset(bprm->buf,0,BINPRM_BUF_SIZE);
43return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
44 }

             1
            /*
             2
             * This structure defines the functions that are used to load the binary formats that

             3
             * linux accepts.

             4
            */
             5
            struct
             linux_binfmt {

             6
            struct
             list_head lh;

             7
            struct module *module;
 8int (*load_binary)(struct linux_binprm *, struct  pt_regs * regs);
 9int (*load_shlib)(struct file *);
10int (*core_dump)(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
11     unsigned long min_coredump;    /* minimal dump size */12int hasvdso;
13 };