diff options
Diffstat (limited to 'mount/mntent.c')
| -rw-r--r-- | mount/mntent.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/mount/mntent.c b/mount/mntent.c new file mode 100644 index 000000000..0be20e8ca --- /dev/null +++ b/mount/mntent.c @@ -0,0 +1,214 @@ +/* Private version of the libc *mntent() routines. */ +/* Note slightly different prototypes. */ + +#include <stdio.h> +#include <string.h> /* for index */ +#include <ctype.h> /* for isdigit */ +#include "mntent.h" +#include "sundries.h" /* for xmalloc */ + +/* Unfortunately the classical Unix /etc/mtab and /etc/fstab + do not handle directory names containing spaces. + Here we mangle them, replacing a space by \040. + What do other Unices do? */ + +static unsigned char need_escaping[] = { ' ', '\t', '\n', '\\' }; + +static char * +mangle(unsigned char *s) { + char *ss, *sp; + int n; + + n = strlen(s); + ss = sp = xmalloc(4*n+1); + while(1) { + for (n = 0; n < sizeof(need_escaping); n++) { + if (*s == need_escaping[n]) { + *sp++ = '\\'; + *sp++ = '0' + ((*s & 0300) >> 6); + *sp++ = '0' + ((*s & 070) >> 3); + *sp++ = '0' + (*s & 07); + goto next; + } + } + *sp++ = *s; + if (*s == 0) + break; + next: + s++; + } + return ss; +} + +static int +is_space_or_tab (char c) { + return (c == ' ' || c == '\t'); +} + +static char * +skip_spaces(char *s) { + while (is_space_or_tab(*s)) + s++; + return s; +} + +static char * +skip_nonspaces(char *s) { + while (*s && !is_space_or_tab(*s)) + s++; + return s; +} + +#define isoctal(a) (((a) & ~7) == '0') + +/* returns malloced pointer - no more strdup required */ +static char * +unmangle(char *s) { + char *ret, *ss, *sp; + + ss = skip_nonspaces(s); + ret = sp = xmalloc(ss-s+1); + while(s != ss) { + if (*s == '\\' && isoctal(s[1]) && isoctal(s[2]) && isoctal(s[3])) { + *sp++ = 64*(s[1] & 7) + 8*(s[2] & 7) + (s[3] & 7); + s += 4; + } else + *sp++ = *s++; + } + *sp = 0; + return ret; +} + +/* + * fstat'ing the file and allocating a buffer holding all of it + * may be a bad idea: if the file is /proc/mounttab, the stat + * returns 0. + * (On the other hand, mangling and unmangling is meaningless + * for /proc/mounttab.) + */ + +mntFILE * +my_setmntent (const char *file, char *mode) { + mntFILE *mfp = xmalloc(sizeof(*mfp)); + + mfp->mntent_fp = fopen (file, mode); + mfp->mntent_file = xstrdup(file); + mfp->mntent_errs = (mfp->mntent_fp == NULL); + mfp->mntent_softerrs = 0; + mfp->mntent_lineno = 0; + return mfp; +} + +void +my_endmntent (mntFILE *mfp) { + if (mfp) { + if (mfp->mntent_fp) + fclose(mfp->mntent_fp); + if (mfp->mntent_file) + free(mfp->mntent_file); + free(mfp); + } +} + + +int +my_addmntent (mntFILE *mfp, struct mntent *mnt) { + char *m1, *m2, *m3, *m4; + int res; + + if (fseek (mfp->mntent_fp, 0, SEEK_END)) + return 1; /* failure */ + + m1 = mangle(mnt->mnt_fsname); + m2 = mangle(mnt->mnt_dir); + m3 = mangle(mnt->mnt_type); + m4 = mangle(mnt->mnt_opts); + + res = ((fprintf (mfp->mntent_fp, "%s %s %s %s %d %d\n", + m1, m2, m3, m4, mnt->mnt_freq, mnt->mnt_passno) + < 0) ? 1 : 0); + + free(m1); + free(m2); + free(m3); + free(m4); + return res; +} + +/* Read the next entry from the file fp. Stop reading at an incorrect entry. */ +struct mntent * +my_getmntent (mntFILE *mfp) { + static char buf[4096]; + static struct mntent me; + char *s; + + again: + if (mfp->mntent_errs || mfp->mntent_softerrs >= ERR_MAX) + return NULL; + + /* read the next non-blank non-comment line */ + do { + if (fgets (buf, sizeof(buf), mfp->mntent_fp) == NULL) + return NULL; + + mfp->mntent_lineno++; + s = index (buf, '\n'); + if (s == NULL) { + /* Missing final newline? Otherwise extremely */ + /* long line - assume file was corrupted */ + if (feof(mfp->mntent_fp)) { + fprintf(stderr, "[mntent]: warning: no final " + "newline at the end of %s\n", + mfp->mntent_file); + s = index (buf, 0); + } else { + mfp->mntent_errs = 1; + goto err; + } + } + *s = 0; + s = skip_spaces(buf); + } while (*s == '\0' || *s == '#'); + + me.mnt_fsname = unmangle(s); + s = skip_nonspaces(s); + s = skip_spaces(s); + me.mnt_dir = unmangle(s); + s = skip_nonspaces(s); + s = skip_spaces(s); + me.mnt_type = unmangle(s); + s = skip_nonspaces(s); + s = skip_spaces(s); + me.mnt_opts = unmangle(s); + s = skip_nonspaces(s); + s = skip_spaces(s); + + if(isdigit(*s)) { + me.mnt_freq = atoi(s); + while(isdigit(*s)) s++; + } else + me.mnt_freq = 0; + if(*s && !is_space_or_tab(*s)) + goto err; + + s = skip_spaces(s); + if(isdigit(*s)) { + me.mnt_passno = atoi(s); + while(isdigit(*s)) s++; + } else + me.mnt_passno = 0; + if(*s && !is_space_or_tab(*s)) + goto err; + + /* allow more stuff, e.g. comments, on this line */ + + return &me; + + err: + mfp->mntent_softerrs++; + fprintf(stderr, "[mntent]: line %d in %s is bad%s\n", + mfp->mntent_lineno, mfp->mntent_file, + (mfp->mntent_errs || mfp->mntent_softerrs >= ERR_MAX) ? + "; rest of file ignored" : ""); + goto again; +} |