My Project  debian-1:4.1.1-p2+ds-4build3
omFindExec.c
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1 /*******************************************************************
2  * File: omFindExec.c
3  * Purpose: routine which determines absolute pathname of executable
4  * Author: obachman (Olaf Bachmann)
5  * Created: 11/99
6  *******************************************************************/
7 
8 
9 #include "singular_resourcesconfig.h"
10 
11 
12 #if defined(HAVE_UNISTD_H) && defined(STDC_HEADERS)
13 
14 #ifdef HAVE_UNISTD_H
15 #include <unistd.h> /* always defiend */
16 #endif
17 
18 #include <stdlib.h>
19 #include <string.h>
20 
21 #include "omFindExec.h"
22 
23 #ifndef MAXPATHLEN
24 #define MAXPATHLEN 1024
25 #endif
26 
27 /* ABSOLUTE_FILENAME_P (fname): True if fname is an absolute filename */
28 #define ABSOLUTE_FILENAME_P(fname) (fname[0] == '/')
29 
30 /* Return the absolute name of the program named NAME. This function
31  searches the directories in the PATH environment variable if PROG
32  has no directory components. */
33 #ifndef HAVE_READLINK
34 char * omFindExec (const char *name, char* executable)
35 #else
36 static char * omFindExec_link (const char *name, char* executable)
37 #endif
38 {
39  char *search;
40  char *p;
41  char tbuf[MAXPATHLEN];
42 
43  if (ABSOLUTE_FILENAME_P(name))
44  {
45  /* If the named file exists then return it. */
46  if (! access (name, F_OK)) //think of libSingular.so as main binary
47  // r or x is required
48  {
49  strcpy(executable, name);
50  return executable;
51  }
52  }
53  else
54  {
55  if (((name[0] == '.') && (name[1] == '/')) ||
56  ((name[0] == '.') && (name[1] == '.') && (name[2] == '/')) ||
57  strchr(name, '/') != NULL)
58  {
59 
60 #ifdef HAVE_GETCWD
61  getcwd (tbuf, MAXPATHLEN);
62 #else
63 # ifdef HAVE_GETWD
64  getwd (tbuf);
65 # endif
66 #endif
67  strcat (tbuf, "/");
68  strcat (tbuf, name);
69  if (! access(tbuf, F_OK))
70  {
71  strcpy(executable, tbuf);
72  return executable;
73  }
74  }
75 
76 
77  search = getenv("PATH");
78 /* for winnt under msdos, cwd is implictly in the path */
79  p = search;
80 
81  if (p != NULL)
82  {
83  while (1)
84  {
85  char *next;
86  next = tbuf;
87 
88  /* Copy directory name into [tbuf]. */
89  /* This is somewhat tricky: empty names mean cwd, w.r.t. some
90  shell spec */
91  while (*p && *p != ':')
92  *next ++ = *p ++;
93  *next = '\0';
94 
95  if ((tbuf[0] == '.' && tbuf[1] == '\0') || tbuf[0] == '\0') {
96 #ifdef HAVE_GETCWD
97  getcwd (tbuf, MAXPATHLEN);
98 #else
99 # ifdef HAVE_GETWD
100  getwd (tbuf);
101 # endif
102 #endif
103  }
104 
105  if (tbuf[strlen(tbuf)-1] != '/') strcat(tbuf, "/");
106  strcat (tbuf, name);
107 
108  /* If the named file exists, then return it. */
109  if (! access (tbuf, F_OK))
110  {
111  strcpy(executable, tbuf);
112  return executable;
113  }
114 
115  if (*p != '\0')
116  {
117  p ++;
118  }
119  else
120  {
121  break;
122  }
123  }
124  }
125  }
126  return NULL;
127 }
128 
129 #ifdef HAVE_READLINK
130 /* similar to readlink, but dont' mess up absolute pathnames */
131 static int my_readlink(const char* name, char* buf, size_t bufsize)
132 {
133  char buf2[MAXPATHLEN];
134  int ret;
135 
136  if ((ret = readlink(name, buf2, bufsize)) > 0)
137  {
138  buf2[ret] = 0;
139  if (*name == '/' && *buf2 != '/')
140  {
141  char* last = strrchr(name, '/');
142  int i = 0;
143  while (&(name[i]) != last)
144  {
145  buf[i] = name[i];
146  i++;
147  }
148  buf[i] = '/';
149  i++;
150  strcpy(&(buf[i]), buf2);
151  return i + ret;
152  }
153  else
154  {
155  strcpy(buf, buf2);
156  }
157  }
158  return ret;
159 }
160 
161 #define MAX_LINK_LEVEL 10
162 /* similar to readlink (cf. man readlink), except that symbolic links are
163  followed up to MAX_LINK_LEVEL
164 */
165 static int full_readlink(const char* name, char* buf, size_t bufsize)
166 {
167  int ret;
168 
169  if ((ret=my_readlink(name, buf, bufsize)) > 0)
170  {
171  char buf2[MAXPATHLEN];
172  int ret2, i = 0;
173 
174  do
175  {
176  buf[ret] = '\0';
177  if ((ret2 = my_readlink(buf, buf2, MAXPATHLEN)) > 0)
178  {
179  i++;
180  buf2[ret2] = '\0';
181  strcpy(buf, buf2);
182  ret = ret2;
183  }
184  else
185  {
186  return ret;
187  }
188  }
189  while (i<MAX_LINK_LEVEL);
190  }
191  return -1;
192 }
193 
194 #ifdef __CYGWIN__
195 /* for windows, serch first for .exe */
196 char * _omFindExec (const char *name, char* exec);
197 char* omFindExec(const char *name, char* exec)
198 {
199 
200  if (strstr(name, ".exe") == NULL)
201  {
202  char buf[MAXPATHLEN];
203  char* ret;
204  strcpy(buf, name);
205  strcat(buf, ".exe");
206  ret = _omFindExec(buf, exec);
207  if (ret != NULL) return ret;
208  }
209  return _omFindExec(name, exec);
210 }
211 #else
212 #define _omFindExec omFindExec
213 #endif
214 
215 char * _omFindExec (const char *name, char* exec)
216 {
217  char * link = omFindExec_link(name, exec);
218  char buf[MAXPATHLEN];
219  int ret;
220 
221  if (link == NULL && (ret=full_readlink(name, buf, MAXPATHLEN)) > 0)
222  {
223  buf[ret] ='\0';
224  link = omFindExec_link(buf, exec);
225  }
226  if (link != NULL && (ret=full_readlink(link, buf, MAXPATHLEN)) > 0)
227  {
228  char *p = strrchr(link, '/');
229 
230 
231  if(p!=NULL) *(p+1)='\0';
232  buf[ret]='\0';
233 
234  if (buf[0] != '/')
235  {
236  strcpy(exec, link);
237  strcat(exec, buf);
238  }
239  else
240  {
241  strcpy(exec, buf);
242  }
243 
244  return exec;
245  }
246  return link;
247 }
248 #endif /* HAVE_READLINK */
249 
250 #else
251 
252 char* omFindExec (const char *name, char* exec)
253 {
254  return name;
255 }
256 
257 #endif /* defined(HAVE_UNISTD_H) && defined(STDC_HEADERS) */
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omFindExec.h
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omFindExec
char * omFindExec(const char *name, char *exec)
Definition: omFindExec.c:252
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