📄 exec.c
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<!doctype html public "-//W3C//DTD HTML 3.2//EN"><html><head><title>Linux/fs/exec.c</title><meta http-equiv=Content-Type content="text/html; charset=gb2312"><base href="http://oldlinux.org/lxr/http/"></head><body bgcolor=white><div align=center> [<b><i>源代码浏览</i></b>] [<a href="diff/fs/exec.c">区别标定</a>] [<a href="ident">标识符搜索</a>] [<a href="search">文本搜索</a>] [<a href="find">文件搜索</a>]</div><h1 align=center> <a href="http:/"> OldLinux</a> <a href="http:blurb.html"> 交叉引用</a><br> <a href="source/">Linux</a>/<a href="source/fs/">fs</a>/<a href="source/fs/exec.c">exec.c</a></h1><div align=center> <b>版本:</b> [<a href="source/fs/exec.c?v=1.0">1.0</a>] [<a href="source/fs/exec.c?v=0.99.11">0.99.11</a>] [<a href="source/fs/exec.c?v=0.99">0.99</a>] [<a href="source/fs/exec.c?v=0.97">0.97</a>] [<a href="source/fs/exec.c?v=0.96a">0.96a</a>] [<a href="source/fs/exec.c?v=0.95">0.95</a>] [<a href="source/fs/exec.c?v=0.12">0.12</a>] [<b><i>0.11</i></b>] [<a href="source/fs/exec.c?v=0.01">0.01</a>] <br> <b>体系结构:</b> [<b><i>i386</i></b>] <br></div><hr><pre> <a name=L1 href="source/fs/exec.c#L1">1</a> <b><i>/*</i></b> <a name=L2 href="source/fs/exec.c#L2">2</a> <b><i> * linux/fs/exec.c</i></b> <a name=L3 href="source/fs/exec.c#L3">3</a> <b><i> *</i></b> <a name=L4 href="source/fs/exec.c#L4">4</a> <b><i> * (C) 1991 Linus Torvalds</i></b> <a name=L5 href="source/fs/exec.c#L5">5</a> <b><i> */</i></b> <a name=L6 href="source/fs/exec.c#L6">6</a> <a name=L7 href="source/fs/exec.c#L7">7</a> <b><i>/*</i></b> <a name=L8 href="source/fs/exec.c#L8">8</a> <b><i> * #!-checking implemented by tytso.</i></b> <a name=L9 href="source/fs/exec.c#L9">9</a> <b><i> */</i></b> <a name=L10 href="source/fs/exec.c#L10">10</a> <a name=L11 href="source/fs/exec.c#L11">11</a> <b><i>/*</i></b> <a name=L12 href="source/fs/exec.c#L12">12</a> <b><i> * Demand-loading implemented 01.12.91 - no need to read anything but</i></b> <a name=L13 href="source/fs/exec.c#L13">13</a> <b><i> * the header into memory. The inode of the executable is put into</i></b> <a name=L14 href="source/fs/exec.c#L14">14</a> <b><i> * "current->executable", and page faults do the actual loading. Clean.</i></b> <a name=L15 href="source/fs/exec.c#L15">15</a> <b><i> *</i></b> <a name=L16 href="source/fs/exec.c#L16">16</a> <b><i> * Once more I can proudly say that linux stood up to being changed: it</i></b> <a name=L17 href="source/fs/exec.c#L17">17</a> <b><i> * was less than 2 hours work to get demand-loading completely implemented.</i></b> <a name=L18 href="source/fs/exec.c#L18">18</a> <b><i> */</i></b> <a name=L19 href="source/fs/exec.c#L19">19</a> <a name=L20 href="source/fs/exec.c#L20">20</a> #include <errno.h> <a name=L21 href="source/fs/exec.c#L21">21</a> #include <string.h> <a name=L22 href="source/fs/exec.c#L22">22</a> #include <sys/stat.h> <a name=L23 href="source/fs/exec.c#L23">23</a> #include <a.out.h> <a name=L24 href="source/fs/exec.c#L24">24</a> <a name=L25 href="source/fs/exec.c#L25">25</a> #include <linux/fs.h> <a name=L26 href="source/fs/exec.c#L26">26</a> #include <linux/sched.h> <a name=L27 href="source/fs/exec.c#L27">27</a> #include <linux/kernel.h> <a name=L28 href="source/fs/exec.c#L28">28</a> #include <linux/mm.h> <a name=L29 href="source/fs/exec.c#L29">29</a> #include <asm/segment.h> <a name=L30 href="source/fs/exec.c#L30">30</a> <a name=L31 href="source/fs/exec.c#L31">31</a> extern int <a href="ident?i=sys_exit">sys_exit</a>(int exit_code); <a name=L32 href="source/fs/exec.c#L32">32</a> extern int <a href="ident?i=sys_close">sys_close</a>(int fd); <a name=L33 href="source/fs/exec.c#L33">33</a> <a name=L34 href="source/fs/exec.c#L34">34</a> <b><i>/*</i></b> <a name=L35 href="source/fs/exec.c#L35">35</a> <b><i> * MAX_ARG_PAGES defines the number of pages allocated for arguments</i></b> <a name=L36 href="source/fs/exec.c#L36">36</a> <b><i> * and envelope for the new program. 32 should suffice, this gives</i></b> <a name=L37 href="source/fs/exec.c#L37">37</a> <b><i> * a maximum env+arg of 128kB !</i></b> <a name=L38 href="source/fs/exec.c#L38">38</a> <b><i> */</i></b> <a name=L39 href="source/fs/exec.c#L39">39</a> #define <a href="ident?i=MAX_ARG_PAGES">MAX_ARG_PAGES</a> 32 <a name=L40 href="source/fs/exec.c#L40">40</a> <a name=L41 href="source/fs/exec.c#L41">41</a> <b><i>/*</i></b> <a name=L42 href="source/fs/exec.c#L42">42</a> <b><i> * create_tables() parses the env- and arg-strings in new user</i></b> <a name=L43 href="source/fs/exec.c#L43">43</a> <b><i> * memory and creates the pointer tables from them, and puts their</i></b> <a name=L44 href="source/fs/exec.c#L44">44</a> <b><i> * addresses on the "stack", returning the new stack pointer value.</i></b> <a name=L45 href="source/fs/exec.c#L45">45</a> <b><i> */</i></b> <a name=L46 href="source/fs/exec.c#L46">46</a> static unsigned long * <a href="ident?i=create_tables">create_tables</a>(char * p,int argc,int envc) <a name=L47 href="source/fs/exec.c#L47">47</a> { <a name=L48 href="source/fs/exec.c#L48">48</a> unsigned long *<a href="ident?i=argv">argv</a>,*<a href="ident?i=envp">envp</a>; <a name=L49 href="source/fs/exec.c#L49">49</a> unsigned long * sp; <a name=L50 href="source/fs/exec.c#L50">50</a> <a name=L51 href="source/fs/exec.c#L51">51</a> sp = (unsigned long *) (0xfffffffc & (unsigned long) p); <a name=L52 href="source/fs/exec.c#L52">52</a> sp -= envc+1; <a name=L53 href="source/fs/exec.c#L53">53</a> <a href="ident?i=envp">envp</a> = sp; <a name=L54 href="source/fs/exec.c#L54">54</a> sp -= argc+1; <a name=L55 href="source/fs/exec.c#L55">55</a> <a href="ident?i=argv">argv</a> = sp; <a name=L56 href="source/fs/exec.c#L56">56</a> <a href="ident?i=put_fs_long">put_fs_long</a>((unsigned long)<a href="ident?i=envp">envp</a>,--sp); <a name=L57 href="source/fs/exec.c#L57">57</a> <a href="ident?i=put_fs_long">put_fs_long</a>((unsigned long)<a href="ident?i=argv">argv</a>,--sp); <a name=L58 href="source/fs/exec.c#L58">58</a> <a href="ident?i=put_fs_long">put_fs_long</a>((unsigned long)argc,--sp); <a name=L59 href="source/fs/exec.c#L59">59</a> while (argc-->0) { <a name=L60 href="source/fs/exec.c#L60">60</a> <a href="ident?i=put_fs_long">put_fs_long</a>((unsigned long) p,<a href="ident?i=argv">argv</a>++); <a name=L61 href="source/fs/exec.c#L61">61</a> while (<a href="ident?i=get_fs_byte">get_fs_byte</a>(p++)) <b><i>/* nothing */</i></b> ; <a name=L62 href="source/fs/exec.c#L62">62</a> } <a name=L63 href="source/fs/exec.c#L63">63</a> <a href="ident?i=put_fs_long">put_fs_long</a>(0,<a href="ident?i=argv">argv</a>); <a name=L64 href="source/fs/exec.c#L64">64</a> while (envc-->0) { <a name=L65 href="source/fs/exec.c#L65">65</a> <a href="ident?i=put_fs_long">put_fs_long</a>((unsigned long) p,<a href="ident?i=envp">envp</a>++); <a name=L66 href="source/fs/exec.c#L66">66</a> while (<a href="ident?i=get_fs_byte">get_fs_byte</a>(p++)) <b><i>/* nothing */</i></b> ; <a name=L67 href="source/fs/exec.c#L67">67</a> } <a name=L68 href="source/fs/exec.c#L68">68</a> <a href="ident?i=put_fs_long">put_fs_long</a>(0,<a href="ident?i=envp">envp</a>); <a name=L69 href="source/fs/exec.c#L69">69</a> return sp; <a name=L70 href="source/fs/exec.c#L70">70</a> } <a name=L71 href="source/fs/exec.c#L71">71</a> <a name=L72 href="source/fs/exec.c#L72">72</a> <b><i>/*</i></b> <a name=L73 href="source/fs/exec.c#L73">73</a> <b><i> * count() counts the number of arguments/envelopes</i></b> <a name=L74 href="source/fs/exec.c#L74">74</a> <b><i> */</i></b> <a name=L75 href="source/fs/exec.c#L75">75</a> static int <a href="ident?i=count">count</a>(char ** <a href="ident?i=argv">argv</a>) <a name=L76 href="source/fs/exec.c#L76">76</a> { <a name=L77 href="source/fs/exec.c#L77">77</a> int i=0; <a name=L78 href="source/fs/exec.c#L78">78</a> char ** tmp; <a name=L79 href="source/fs/exec.c#L79">79</a> <a name=L80 href="source/fs/exec.c#L80">80</a> if (tmp = <a href="ident?i=argv">argv</a>) <a name=L81 href="source/fs/exec.c#L81">81</a> while (<a href="ident?i=get_fs_long">get_fs_long</a>((unsigned long *) (tmp++))) <a name=L82 href="source/fs/exec.c#L82">82</a> i++; <a name=L83 href="source/fs/exec.c#L83">83</a> <a name=L84 href="source/fs/exec.c#L84">84</a> return i; <a name=L85 href="source/fs/exec.c#L85">85</a> } <a name=L86 href="source/fs/exec.c#L86">86</a> <a name=L87 href="source/fs/exec.c#L87">87</a> <b><i>/*</i></b> <a name=L88 href="source/fs/exec.c#L88">88</a> <b><i> * 'copy_string()' copies argument/envelope strings from user</i></b> <a name=L89 href="source/fs/exec.c#L89">89</a> <b><i> * memory to free pages in kernel mem. These are in a format ready</i></b> <a name=L90 href="source/fs/exec.c#L90">90</a> <b><i> * to be put directly into the top of new user memory.</i></b> <a name=L91 href="source/fs/exec.c#L91">91</a> <b><i> *</i></b> <a name=L92 href="source/fs/exec.c#L92">92</a> <b><i> * Modified by TYT, 11/24/91 to add the from_kmem argument, which specifies</i></b> <a name=L93 href="source/fs/exec.c#L93">93</a> <b><i> * whether the string and the string array are from user or kernel segments:</i></b> <a name=L94 href="source/fs/exec.c#L94">94</a> <b><i> * </i></b> <a name=L95 href="source/fs/exec.c#L95">95</a> <b><i> * from_kmem argv * argv **</i></b> <a name=L96 href="source/fs/exec.c#L96">96</a> <b><i> * 0 user space user space</i></b> <a name=L97 href="source/fs/exec.c#L97">97</a> <b><i> * 1 kernel space user space</i></b> <a name=L98 href="source/fs/exec.c#L98">98</a> <b><i> * 2 kernel space kernel space</i></b> <a name=L99 href="source/fs/exec.c#L99">99</a> <b><i> * </i></b><a name=L100 href="source/fs/exec.c#L100">100</a> <b><i> * We do this by playing games with the fs segment register. Since it</i></b><a name=L101 href="source/fs/exec.c#L101">101</a> <b><i> * it is expensive to load a segment register, we try to avoid calling</i></b>⌨️ 快捷键说明
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