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f5bcab4b WJ |
1 | /* elvrec.c */ |
2 | ||
3 | /* This file contains the file recovery program */ | |
4 | ||
5 | /* Author: | |
6 | * Steve Kirkendall | |
7 | * 14407 SW Teal Blvd. #C | |
8 | * Beaverton, OR 97005 | |
9 | * kirkenda@cs.pdx.edu | |
10 | */ | |
11 | ||
12 | ||
13 | #include <stdio.h> | |
14 | #include "config.h" | |
15 | #include "vi.h" | |
16 | ||
17 | void recover(basename, outname) | |
18 | char *basename; /* the name of the file to recover */ | |
19 | char *outname; /* the name of the file to write to */ | |
20 | { | |
21 | char pathname[500]; /* full pathname of the file to recover */ | |
22 | char line[600]; /* a line from the /usr/preserve/Index file */ | |
23 | int ch; /* a character from the text being recovered */ | |
24 | FILE *from; /* the /usr/preserve file, or /usr/preserve/Index */ | |
25 | FILE *to; /* the user's text file */ | |
26 | char *ptr; | |
27 | #if OSK | |
28 | int uid; | |
29 | #endif | |
30 | ||
31 | /* convert basename to a full pathname */ | |
32 | if (basename) | |
33 | { | |
34 | #ifndef CRUNCH | |
35 | # if MSDOS || TOS | |
36 | if (!basename[0] || basename[1] != ':') | |
37 | # else | |
38 | if (basename[0] != SLASH) | |
39 | # endif | |
40 | { | |
41 | ptr = getcwd(pathname, sizeof pathname); | |
42 | if (ptr != pathname) | |
43 | { | |
44 | strcpy(pathname, ptr); | |
45 | } | |
46 | ptr = pathname + strlen(pathname); | |
47 | *ptr++ = SLASH; | |
48 | strcpy(ptr, basename); | |
49 | } | |
50 | else | |
51 | #endif | |
52 | { | |
53 | strcpy(pathname, basename); | |
54 | } | |
55 | } | |
56 | ||
57 | #if OSK | |
58 | uid = getuid(); | |
59 | if(setuid(0)) | |
60 | exit(_errmsg(errno, "Can't set uid\n")); | |
61 | #endif | |
62 | /* scan the /usr/preserve/Index file, for the *oldest* unrecovered | |
63 | * version of this file. | |
64 | */ | |
65 | from = fopen(PRSVINDEX, "r"); | |
66 | while (from && fgets(line, sizeof line, from)) | |
67 | { | |
68 | /* strip off the newline from the end of the string */ | |
69 | line[strlen(line) - 1] = '\0'; | |
70 | ||
71 | /* parse the line into a "preserve" name and a "text" name */ | |
72 | for (ptr = line; *ptr != ' '; ptr++) | |
73 | { | |
74 | } | |
75 | *ptr++ = '\0'; | |
76 | ||
77 | /* If the "preserve" file is missing, then ignore this line | |
78 | * because it describes a file that has already been recovered. | |
79 | */ | |
80 | if (access(line, 0) < 0) | |
81 | { | |
82 | continue; | |
83 | } | |
84 | ||
85 | /* are we looking for a specific file? */ | |
86 | if (basename) | |
87 | { | |
88 | /* quit if we found it */ | |
89 | if (!strcmp(ptr, pathname)) | |
90 | { | |
91 | break; | |
92 | } | |
93 | } | |
94 | else | |
95 | { | |
96 | /* list this file as "available for recovery" */ | |
97 | puts(ptr); | |
98 | } | |
99 | } | |
100 | ||
101 | /* file not found? */ | |
102 | if (!basename || !from || feof(from)) | |
103 | { | |
104 | if (from != NULL) fclose(from); | |
105 | if (basename) | |
106 | { | |
107 | fprintf(stderr, "%s: no recovered file has that exact name\n", pathname); | |
108 | } | |
109 | return; | |
110 | } | |
111 | if (from != NULL) fclose(from); | |
112 | ||
113 | /* copy the recovered text back into the user's file... */ | |
114 | ||
115 | /* open the /usr/preserve file for reading */ | |
116 | from = fopen(line, "r"); | |
117 | if (!from) | |
118 | { | |
119 | perror(line); | |
120 | exit(2); | |
121 | } | |
122 | ||
123 | #if ANY_UNIX | |
124 | /* Be careful about user-id. We want to be running under the user's | |
125 | * real id when we open/create the user's text file... but we want | |
126 | * to be superuser when we delete the /usr/preserve file. For UNIX, | |
127 | * we accomplish this by deleting the /usr/preserve file *now*, | |
128 | * when it is open but before we've read it. Then we revert to the | |
129 | * user's real id. | |
130 | */ | |
131 | unlink(line); | |
132 | setuid(getuid()); | |
133 | #endif | |
134 | #if OSK | |
135 | setuid(uid); | |
136 | #endif | |
137 | ||
138 | if (outname == NULL) return; | |
139 | ||
140 | /* open the user's file for writing */ | |
141 | to = fopen(outname, "w"); | |
142 | if (!to) | |
143 | { | |
144 | perror(ptr); | |
145 | exit(2); | |
146 | } | |
147 | ||
148 | /* copy the text */ | |
149 | while ((ch = getc(from)) != EOF) | |
150 | { | |
151 | putc(ch, to); | |
152 | } | |
153 | ||
154 | #if !ANY_UNIX | |
155 | #if OSK | |
156 | fclose(from); | |
157 | setuid(0); | |
158 | #endif | |
159 | /* delete the /usr/preserve file */ | |
160 | unlink(line); | |
161 | #if OSK | |
162 | setuid(uid); | |
163 | #endif | |
164 | #endif | |
165 | } | |
166 | ||
167 | main(argc, argv) | |
168 | int argc; | |
169 | char **argv; | |
170 | { | |
171 | /* check arguments */ | |
172 | if (argc > 3) | |
173 | { | |
174 | fprintf(stderr, "usage: %s [preserved_file [recovery_file]]\n", argv[0]); | |
175 | exit(1); | |
176 | } | |
177 | ||
178 | /* recover the requested file, or list recoverable files */ | |
179 | if (argc == 3) | |
180 | { | |
181 | /* recover the file, but write it to a different filename */ | |
182 | recover (argv[1], argv[2]); | |
183 | } | |
184 | else if (argc == 2) | |
185 | { | |
186 | /* recover the file */ | |
187 | recover(argv[1], argv[1]); | |
188 | } | |
189 | else | |
190 | { | |
191 | /* list the recoverable files */ | |
192 | recover((char *)0, (char *)0); | |
193 | } | |
194 | ||
195 | /* success! */ | |
196 | exit(0); | |
197 | } |